Patterns of efficiency and degradation of composite polymer solar cells

NARCIS (Netherlands)

Jeranko, T; Tributsch, H; Sariciftci, NS; Hummelen, JC

2004-01-01

Bulk-heterojunction plastic solar cells (PSC) produced from a conjugated polymer, poly(2-methoxy-5-(3',7'-dimethyloctyl-oxy)-1,4-phenylenevinylene) (MDMO-PPV), and a methanofullerene [6,6]-phenyl C-61-butyric acid methyl ester (PCBM) were investigated using photocurrent imaging techniques to

Electroluminescent Characteristics of DBPPV–ZnO Nanocomposite Polymer Light Emitting Devices

Directory of Open Access Journals (Sweden)

Madhava Rao MV

2009-01-01

Full Text Available Abstract We have demonstrated that fabrication and characterization of nanocomposite polymer light emitting devices with metal Zinc Oxide (ZnO nanoparticles and 2,3-dibutoxy-1,4-poly(phenylenevinylene (DBPPV. The current and luminance characteristics of devices with ZnO nanoparticles are much better than those of device with pure DBPPV. Optimized maximum luminance efficiencies of DBPPV–ZnO (3:1 wt% before annealing (1.78 cd/A and after annealing (2.45 cd/A having a brightness 643 and 776 cd/m2at a current density of 36.16 and 31.67 mA/cm2are observed, respectively. Current density–voltage and brightness–voltage characteristics indicate that addition of ZnO nanoparticles can facilitate electrical injection and charge transport. The thermal annealing is thought to result in the formation of an interfacial layer between emissive polymer film and cathode.

Effect of the polymer emission on the electroluminescence characteristics of n-ZnO nanorods/p-polymer hybrid light emitting diode

Science.gov (United States)

Zaman, S.; Zainelabdin, A.; Amin, G.; Nur, O.; Willander, M.

2011-09-01

Hybrid light emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods and polymers (single and blended) were fabricated and characterized. The ZnO nanorods were grown by the chemical bath deposition method at 50°C. Three different LEDs, with blue emitting, orange-red emitting or their blended polymer together with ZnO nanorods, were fabricated and studied. The current-voltage characteristics show good diode behavior with an ideality factor in the range of 2.1 to 2.27 for all three devices. The electroluminescence spectrum (EL) of the blended device has an emission range from 450 nm to 750 nm, due to the intermixing of the blue emission generated by poly(9,9-dioctylfluorene) denoted as PFO with orange-red emission produced by poly(2-methoxy-5(20-ethyl-hexyloxy)-1,4-phenylenevinylene) 1,4-phenylenevinylene) symbolized as MEH PPV combined with the deep-band emission (DBE) of the ZnO nanorods, i.e. it covers the whole visible region and is manifested as white light. The CIE color coordinates showed bluish, orange-red and white emission from the PFO, MEH PPV and blended LEDs with ZnO nanorods, respectively. These results indicate that the choice of the polymer with proper concentration is critical to the emitted color in ZnO nanorods/p-organic polymer LEDs and careful design should be considered to obtain intrinsic white light sources.

Polymer filtration: A new technology for selective metals recovery

Energy Technology Data Exchange (ETDEWEB)

Smith, B.F.; Robison, T.W.; Cournoyer, M.E.; Wilson, K.V.; Sauer, N.N.; Mullen, K.I.; Lu, M.T.; Jarvinen, J.J.

1995-04-01

Polymer Filtration (PF) was evaluated for the recovery of electroplating metal ions (zinc and nickel) from rinse waters. Polymer Filtration combines the use of water-soluble metal-binding polymers and ultrafiltration to concentrate metal ions from dilute rinse water solutions. The metal ions are retained by the polymers; the smaller, unbound species freely pass through the ultrafiltration membrane. By using this process the ultrafiltered permeate more than meets EPA discharge limits. The metal ions are recovered from the concentrated polymer solution by pH adjustment using diafiltration and can be recycled to the original electroplating baths with no deleterious effects on the test panels. Metal-ion recovery is accomplished without producing sludge.

21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer/metal semi-constrained... Devices § 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis. (a) Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a device...

Hybrid zinc oxide conjugated polymer bulk heterojunction solar cells

NARCIS (Netherlands)

Beek, W.J.E.; Wienk, M.M.; Kemerink, M.; Yang, X.N.; Janssen, R.A.J.

2005-01-01

Bulk heterojunction photovoltaic devices based on blends of a conjugated polymer poly[2-methoxy-5-(3‘,7‘-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) as electron donor and crystalline ZnO nanoparticles (nc-ZnO) as electron acceptor have been studied. Composite nc-ZnO:MDMO-PPV films were cast

Hydrogen bonding as the origin of the switching behavior in dithiolated phenylene-vinylene oligomers

KAUST Repository

Obodo, Tobechukwu Joshua; Gkionis, Konstantinos; Rungger, Ivan; Sanvito, Stefano; Schwingenschlö gl, Udo

2013-01-01

We investigate theoretically the switching behavior of a dithiolated phenylene-vinylene oligomer sandwiched between Au(111) electrodes using self-interaction corrected density-functional theory combined with the nonequilibrium Green

Deformation limits of polymer coated metal sheets

NARCIS (Netherlands)

Van Den Bosch, M.J.W.J.P.; Schreurs, P.J.G; Geers, M.G.D.

2005-01-01

Polymer coated metals are increasingly used by the packaging and automotive industry. During industrial deformation processes (drawing, roll-forming, bending etc.) the polymer-metal laminate is highly deformed at high deformation rates. These forming conditions can affect the mechanical integrity

Inflammatory myoglandular polyp--a rare but distinct type of colorectal polyps.

Science.gov (United States)

Becheanu, Gabriel; Stamm, Bernhard

2003-01-01

The aim of this paper was to report another example of a rare type of colorectal polyps, the inflammatory myoglandular polyp, and to reaffirm this type of polyp as a distinct entity. This solitary pedunculated polyp was detected after a single episode of rectal bleeding. It was situated in the sigmoid colon, measured 2.5 cm in greatest diameter, and was composed almost exclusively of smooth muscles and hyperplastic glands. The patient had neither chronic colitis nor diverticula. Clinical presentation, localization, and histology give this type of polyp a unique appearance and justify its designation as a separate entity.

Graphene-Reinforced Metal and Polymer Matrix Composites

Science.gov (United States)

Kasar, Ashish K.; Xiong, Guoping; Menezes, Pradeep L.

2018-06-01

Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. Graphene is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. This article reviews the fabrication followed by mechanical and tribological properties of metal and polymer matrix composites filled with different kinds of graphene, including single-layer, multilayer, and functionalized graphene. Results reported to date in literature indicate that functionalized graphene or graphene oxide-polymer composites are promising materials offering significantly improved strength and frictional properties. A similar trend of improved properties has been observed in case of graphene-metal matrix composites. However, achieving higher graphene loading with uniform dispersion in metal matrix composites remains a challenge. Although graphene-reinforced composites face some challenges, such as understanding the graphene-matrix interaction or fabrication techniques, graphene-reinforced polymer and metal matrix composites have great potential for application in various fields due to their outstanding properties.

Fluid Structure Interaction Analysis in Manufacturing Metal/Polymer Macro-Composites

International Nuclear Information System (INIS)

Baesso, R.; Lucchetta, G.

2007-01-01

Polymer Injection Forming (PIF) is a new manufacturing technology for sheet metal-polymer macro-composites, which results from the combination of injection moulding and sheet metal forming. This process consists on forming the sheet metal according to the boundary of the mould cavity by means of the injected polymer. After cooling, the polymer bonds permanently to the metal resulting in a sheet metal-polymer macro-composite product. Comparing this process to traditional ones (where the polymeric and metal parts are joined together after separate forming) the main advantages are both reduction of production costs and increase of part quality. This paper presents a multi-physics numerical simulation of the process performed in the Ansys/CFX environment

Polymer-supported metals and metal oxide nanoparticles: synthesis, characterization, and applications

International Nuclear Information System (INIS)

Sarkar, Sudipta; Guibal, E.; Quignard, F.; SenGupta, A. K.

2012-01-01

Metal and metal oxide nanoparticles exhibit unique properties in regard to sorption behaviors, magnetic activity, chemical reduction, ligand sequestration among others. To this end, attempts are being continuously made to take advantage of them in multitude of applications including separation, catalysis, environmental remediation, sensing, biomedical applications and others. However, metal and metal oxide nanoparticles lack chemical stability and mechanical strength. They exhibit extremely high pressure drop or head loss in fixed-bed column operation and are not suitable for any flow-through systems. Also, nanoparticles tend to aggregate; this phenomenon reduces their high surface area to volume ratio and subsequently reduces effectiveness. By appropriately dispersing metal and metal oxide nanoparticles into synthetic and naturally occurring polymers, many of the shortcomings can be overcome without compromising the parent properties of the nanoparticles. Furthermore, the appropriate choice of the polymer host with specific functional groups may even lead to the enhancement of the properties of nanoparticles. The synthesis of hybrid materials involves two broad pathways: dispersing the nanoparticles (i) within pre-formed or commercially available polymers; and (ii) during the polymerization process. This review presents a broad coverage of nanoparticles and polymeric/biopolymeric host materials and the resulting properties of the hybrid composites. In addition, the review discusses the role of the Donnan membrane effect exerted by the host functionalized polymer in harnessing the desirable properties of metal and metal oxide nanoparticles for intended applications.

PREPARATION OF A POLYMER ARTICLE FOR SELECTIVE METALLIZATION

DEFF Research Database (Denmark)

2008-01-01

The present invention relates to the field of selective metallization, and in particular to preparing a polymer article for selective metallization by submerging the article in a first liquid, and while submergedirradiate the article by a laser beam the area of the article on which the metal...... is to be deposited. An activation step, prior to the selective metallization, comprises submerging the article in an activation liquid for depositing seedparticles in the selected area. The irradiation of the selected area is proportionate so as to cause a temporary meltingof the polymer in the surface...... of the selected area of the polymer article. The invention is advantageous in that the preparation may be performed with a relatively high scan rate across the polymer article, and in that a quite limited use of toxic chemicals....

Ion conducting polymers and polymer blends for alkali metal ion batteries

Science.gov (United States)

DeSimone, Joseph M.; Pandya, Ashish; Wong, Dominica; Vitale, Alessandra

2017-08-29

Electrolyte compositions for batteries such as lithium ion and lithium air batteries are described. In some embodiments the compositions are liquid compositions comprising (a) a homogeneous solvent system, said solvent system comprising a perfluropolyether (PFPE) and polyethylene oxide (PEO); and (b) an alkali metal salt dissolved in said solvent system. In other embodiments the compositions are solid electrolyte compositions comprising: (a) a solid polymer, said polymer comprising a crosslinked product of a crosslinkable perfluropolyether (PFPE) and a crosslinkable polyethylene oxide (PEO); and (b) an alkali metal ion salt dissolved in said polymer. Batteries containing such compositions as electrolytes are also described.

Stomach Polyps

Science.gov (United States)

... pylori) bacteria are a common cause of the gastritis that contributes to hyperplastic polyps and adenomas. Familial adenomatous polyposis. This rare, inherited syndrome increases the risk of colon cancer and other conditions, including stomach polyps. Certain medications. ...

Gas-phase synthesis of magnetic metal/polymer nanocomposites

Science.gov (United States)

Starsich, Fabian H. L.; Hirt, Ann M.; Stark, Wendelin J.; Grass, Robert N.

2014-12-01

Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

Metallization of Various Polymers by Cold Spray

Science.gov (United States)

Che, Hanqing; Chu, Xin; Vo, Phuong; Yue, Stephen

2018-01-01

Previous results have shown that metallic coatings can be successfully cold sprayed onto polymeric substrates. This paper studies the cold sprayability of various metal powders on different polymeric substrates. Five different substrates were used, including carbon fiber reinforced polymer (CFRP), acrylonitrile butadiene styrene (ABS), polyether ether ketone (PEEK), polyethylenimine (PEI); mild steel was also used as a benchmark substrate. The CFRP used in this work has a thermosetting matrix, and the ABS, PEEK and PEI are all thermoplastic polymers, with different glass transition temperatures as well as a number of distinct mechanical properties. Three metal powders, tin, copper and iron, were cold sprayed with both a low-pressure system and a high-pressure system at various conditions. In general, cold spray on the thermoplastic polymers rendered more positive results than the thermosetting polymers, due to the local thermal softening mechanism in the thermoplastics. Thick copper coatings were successfully deposited on PEEK and PEI. Based on the results, a method is proposed to determine the feasibility and deposition window of cold spraying specific metal powder/polymeric substrate combinations.

Metal-containing radiation-sensitive polymers

International Nuclear Information System (INIS)

Lee, A.Y.

1986-01-01

The copolymers of methyl methacrylate with alkali metal salts (Na, K, and Cs) of methacrylic acid have been prepared by saponification K, and Cs) of methylacrylic acid have been prepared by saponification of the homopolymer poly(methyl methacrylate), PMMA. Low degrees of hydrolysis have been achieved by a heterogeneous system, and from the infrared spectra it has been confirmed that the ester groups of the methyl methacrylates are directly converted to the metal salts of methacrylic acid. These ionomers exhibit pseudo high molecular weights in gel permeation chromatogram, but no appreciable increase in intrinsic viscosities is observed in comparison to PMMA. The coordinated inorganic polymers poly[(dithio-2,2'-diacetato)bis(dimethylsulfoxide)dioxouranium(VI)] and poly[{methylenebis(thio)-2,2'-bis(acetato)}bis(dimethylsulfoxide)dioxouranium(VI)]have been synthesized in dimethyl sulfoxide solution with about 90% yield. The degree of polymerization and the number of average molecular weights of these polymers have been assessed by high resolution nuclear magnetic resonance, with which the acetato end group to the bridging ligand group ratios have been determined. The polymers bridging ligand group ratios have been determined. The polymers have been characterized by employing various techniques: infrared spectra, thermal gravimetric analysis, 13 C solid state nuclear magnetic resonance, and gel permeation chromatography. The prepared polymer samples have been subjected to various doses of 137 Cs gamma radiation under which the polymers predominantly undergo chain scission. The radiation sensitivities of the polymers are assessed by G values which are obtained from gel permeation chromatograms. These uranyl polymers exhibit unusually high G values

SPHENOCHOANAL POLYP: A CASE STUDY

Directory of Open Access Journals (Sweden)

Gaurav

2015-09-01

Full Text Available Sphenochoanal polyp is a rare clinical occurrence as compared to the much common antro - choanal polyp. It originates from the sphenoid sinus and extends into the choana via the sphenoid ostium. We present a case of spheno - choanal polyp and its clinical features and surgical management is discussed. Our aim in this case was to properly d elineate the origin of the polyp and differentiate it from other lesions such as the antro - choanal polyp and meningocele, followed by meticulous endoscopic excision of the polyp

Combined use of polymer composites and metals in engineering structures

International Nuclear Information System (INIS)

Hoa, S.V.

2002-01-01

Polymer matrix composites have found many applications in the construction of light weight structures such as those in aircrafts, automobiles, sports equipment etc. This is because these materials possess high stiffness, high strength and low densities. In applications of polymer matrix composites in the light weight structures, the polymer composites are however, not used by themselves alone in most cases. Usually the polymer composites are used in conjunction with some metal components. The metal components are used either to provide means for joining the composite components or the composites are used to repair the cracked metal structures. The synergistic effect of both metals and composites can provide excellent performance with good economy. This paper presents a few applications where polymer composites are used in conjunction with metals in engineering structures. (author)

Supramolecular organisation of oligo(p-phenylenevinylene) at the air-water interface and in water

NARCIS (Netherlands)

Jonkheijm, P.; Fransen, M.; Schenning, A.P.H.J.; Meijer, E.W.

2001-01-01

Two novel chiral (bola)amphiphilic oligo(p-phenylenevinylene)s (OPVs) have been synthesised and fully characterised. Decoration of the hydrophobic OPV backbone with a hydrophilic tris[tetra(ethylene oxide)]benzene wedge on one side and a hydrophobic tris(alkoxy)benzene wedge on the other side,

Synthesis of biocidal polymers containing metal NPs using an electron beam

International Nuclear Information System (INIS)

Choi, Kwonyong; Kim, Seong-Eun; Kim, Hee-Yeon; Yoon, Jeyong; Lee, Jong-Chan

2012-01-01

Metal containing antibacterial polymers were prepared by the polymerization of methylmethacrylate and methacrylic acid with copper or zinc. When the thin film of the polymers coated on a glass was irradiated with an electron beam, nanoparticles were obtained. It was found that these polymers exhibited a potent antibacterial activity against the Gram-negative bacteria, Escherichia coli. The metal containing polymers showed a 99.999% (5.0 logs) reduction in E. coli at a contact time of 12 h. In addition, polymers had a good antifouling effect against marine organisms. - Graphical abstract: Biocidal activity of Cu nanoparticle/polymer composite film against Gram-negative bacteria. Highlights: ► Metal containing antibacterial polymers were prepared with copper. ► Using the electron beam, nanoparticles were obtained. ► It was found that these polymers exhibited potent biocidal activity against E. coli. ► The metal containing polymers showed a 99.999% reduction of E. coli.

Effect of CoFe magnetic nanoparticles on the hole transport in poly(2-methoxy, 5-(2-ethylhexiloxy) 1,4-phenylenevinylene)

International Nuclear Information System (INIS)

Kumar, Pankaj; Kumar, Hemant; Chand, Suresh; Jain, S C; Kumar, Vikram; Kumar, Vinod; Pant, R P; Tandon, R P

2008-01-01

The effect of doping of CoFe magnetic nanoparticles (MNPs) on the hole transport in poly(2-methoxy,5-(2-ethylhexyloxy)-1,4-phenylenevinylene)(MEH-PPV) thin films has been investigated in the temperature range 280-120 K. Hole transport in MEH-PPV is found to be governed by space-charge-limited-conduction (SCLC) with exponential distribution of traps in energy space. Doping of CoFe MNPs in MEH-PPV reduces the hole mobility from 1 x 10 -5 to 6 x 10 -6 cm 2 V -1 s -1 by introducing new trap sites causing their net density increase from 1 x 10 18 to 2.1 x 10 18 cm -3 , which is likely to result in balanced injection and efficient recombination of charge carriers to improve the performance of polymer light emitting diodes

Selective removal of heavy metal ions by disulfide linked polymer networks

Energy Technology Data Exchange (ETDEWEB)

Ko, Dongah [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark); Lee, Joo Sung [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 (Korea, Republic of); Patel, Hasmukh A. [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Jakobsen, Mogens H. [Department of Micro and Nano technology, Technical University of Denmark, Ørsteds Plads, 345B, 2800 Kgs. Lyngby (Denmark); Hwang, Yuhoon [Department of Environmental Engineering, Seoul National University of Science and Technology, 232 Gongreung-ro, Nowon-gu, Seoul 01811 (Korea, Republic of); Yavuz, Cafer T. [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 (Korea, Republic of); Hansen, Hans Chr. Bruun [Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Andersen, Henrik R., E-mail: henrik@ndersen.net [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark)

2017-06-15

Highlights: • Disulfide/thiol polymer networks are promising as sorbent for heavy metals. • Rapid sorption and high Langmuir affinity constant (a{sub L}) for stormwater treatment. • Selective sorption for copper, cadmium, and zinc in the presence of calcium. • Reusability likely due to structure stability of disulfide linked polymer networks. - Abstract: Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions–copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water.

Selective removal of heavy metal ions by disulfide linked polymer networks

DEFF Research Database (Denmark)

Ko, Dongah; Sung Lee, Joo; Patel, Hasmukh A.

2017-01-01

Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has...... a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal...... sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions―copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water....

Non-radiative recombination losses in polymer light-emitting diodes

NARCIS (Netherlands)

Kuik, M.; Koster, L. J. A.; Dijkstra, A. G.; Wetzelaer, G. A. H.; Blom, P. W. M.

We present a quantitative analysis of the loss of electroluminescence in light-emitting diodes (LEDs) based on poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) due to the combination of non-radiative trap-assisted recombination and exciton quenching at the metallic cathode. It is

Angiomatous nasal polyp: Clinical diagnostic dilemma

Directory of Open Access Journals (Sweden)

Sunder Goyal

2015-03-01

Full Text Available Angiomatous polyp (Angiectatic nasal polyps is rare and its incidence is 4-5% of all nasal polyps. As it occurs with variable clinical features and there is no confirmatory preoperative investigation, clinical diagnosis can be a dilemma. Clinical picture of angiofibroma, simple antrochoanal polyp and inverted papilloma may resemble with each other. As polyps invade surrounding bone, these should be distinguished from a malignant mass. We present an interesting case of an infarcted angiectatic nasal polyp with extensive surrounding bony destruction. Correct preoperative radiological diagnosis is important to avoid unnecessary extensive surgery. Histopathological evaluation of polyps is mandatory since they require different treatment due to difference in the prognosis.

Highly oriented thin films of a substituted oligo(para-phenylenevinylene) on friction-transferred PTFE substrates

NARCIS (Netherlands)

Gill, R.E; Hadziioannou, G; Lang, P.; Garnier, F.; Wittmann, J.C.

Communication: Highly oriented thin films of oligo(p-phenylenevinylene)s, oligoPPVs, provide information about the structure of polyPPV and structure-property relationships. It is shown that deposition of a substituted oligoPPV onto highly preoriented PTFE substrates leads to highly oriented thin

Nanostructural self-organization and dynamic adaptation of metal-polymer tribosystems

Science.gov (United States)

Mashkov, Yu. K.

2017-02-01

The results of investigating the effect of nanosize modifiers of a polymer matrix on the nanostructural self-organization of polymer composites and dynamic adaptation of metal-polymer tribosystems, which considerably affect the wear resistance of polymer composite materials, have been analyzed. It has been shown that the physicochemical nanostructural self-organization processes are developed in metal-polymer tribosystems with the formation of thermotropic liquid-crystal structures of the polymer matrix, followed by the transition of the system to the stationary state with a negative feedback that ensures dynamic adaptation of the tribosystem to given operating conditions.

Photoacoustic imaging for differential diagnosis of benign polyps versus malignant polyps of the gallbladder: A preliminary study

Energy Technology Data Exchange (ETDEWEB)

Chae, Hee Dong; Lee, Jae Young; Han, Joon Koo [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul National University Hospital, Seoul (Korea, Republic of); Jang, Jin Young; Kang, Mee Joo [Div. of Hepatobiliary-Pancreatic Surgery, Department of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Chang, Jin Ho; Kang, Jeeun [Sogang University, Seoul (Korea, Republic of)

2017-09-15

To investigate the feasibility of ex vivo multispectral photoacoustic (PA) imaging in differentiating cholesterol versus neoplastic polyps, and benign versus malignant polyps, of the gallbladder. A total of 38 surgically confirmed gallbladder polyps (24 cholesterol polyps, 4 adenomas, and 10 adenocarcinomas) from 38 patients were prospectively included in this study. The surgical specimens were set on a gel pad immersed in a saline-filled container. The PA intensities of polyps were then measured, using two separate wavelength intervals (421–647 nm and 692–917 nm). Mann-Whitney U test was performed for the comparison of normalized PA intensities between the cholesterol and neoplastic polyps, and between the benign and malignant polyps. Kruskal-Wallis test was conducted for the comparison of normalized PA intensities among the cholesterol polyps, adenomas, and adenocarcinomas. A significant difference was observed in the normalized PA intensities between the cholesterol and neoplastic polyps at 459 nm (median, 1.00 vs. 0.73; p = 0.032). Comparing the benign and malignant polyps, there were significant differences in the normalized PA intensities at 765 nm (median, 0.67 vs. 0.78; p = 0.013), 787 nm (median, 0.65 vs. 0.77; p = 0.034), and 853 nm (median, 0.59 vs. 0.85; p = 0.028). The comparison of the normalized PA intensities among cholesterol polyps, adenomas, and adenocarcinomas demonstrated marginally significant differences at 765 nm (median, 0.67 vs. 0.66 vs. 0.78, respectively; p = 0.049). These preliminary results indicate that benign versus malignant gallbladder polyps might exhibit different spectral patterns on multispectral PA imaging.

Photoacoustic imaging for differential diagnosis of benign polyps versus malignant polyps of the gallbladder: A preliminary study

International Nuclear Information System (INIS)

Chae, Hee Dong; Lee, Jae Young; Han, Joon Koo; Jang, Jin Young; Kang, Mee Joo; Chang, Jin Ho; Kang, Jeeun

2017-01-01

To investigate the feasibility of ex vivo multispectral photoacoustic (PA) imaging in differentiating cholesterol versus neoplastic polyps, and benign versus malignant polyps, of the gallbladder. A total of 38 surgically confirmed gallbladder polyps (24 cholesterol polyps, 4 adenomas, and 10 adenocarcinomas) from 38 patients were prospectively included in this study. The surgical specimens were set on a gel pad immersed in a saline-filled container. The PA intensities of polyps were then measured, using two separate wavelength intervals (421–647 nm and 692–917 nm). Mann-Whitney U test was performed for the comparison of normalized PA intensities between the cholesterol and neoplastic polyps, and between the benign and malignant polyps. Kruskal-Wallis test was conducted for the comparison of normalized PA intensities among the cholesterol polyps, adenomas, and adenocarcinomas. A significant difference was observed in the normalized PA intensities between the cholesterol and neoplastic polyps at 459 nm (median, 1.00 vs. 0.73; p = 0.032). Comparing the benign and malignant polyps, there were significant differences in the normalized PA intensities at 765 nm (median, 0.67 vs. 0.78; p = 0.013), 787 nm (median, 0.65 vs. 0.77; p = 0.034), and 853 nm (median, 0.59 vs. 0.85; p = 0.028). The comparison of the normalized PA intensities among cholesterol polyps, adenomas, and adenocarcinomas demonstrated marginally significant differences at 765 nm (median, 0.67 vs. 0.66 vs. 0.78, respectively; p = 0.049). These preliminary results indicate that benign versus malignant gallbladder polyps might exhibit different spectral patterns on multispectral PA imaging

21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer semi-constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3350 Hip joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/polymer non-constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3120 Ankle joint metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non...

21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

Physical masking process for integrating micro metallic structures on polymer substrate

DEFF Research Database (Denmark)

Islam, Mohammad Aminul; Hansen, Hans Nørgaard

2009-01-01

plasmon devices need micro metallic structures on a polymer substrate with an uniform metal layer thickness in the nanometer range. A well known fabrication process to achieve such metallic surface pattern on polymer substrate is photolithography which involves an expensive mask and toxic chemicals......Integration of micro metallic structures in polymer devices is a broad multi-disciplinary research field, consisting of various combinations of mechanical, chemical and physical fabrication methods. Each of the methods has its specific advantages and disadvantages. Some applications like surface....... The current study shows a novel approach for fabricating thin micro metallic structures on polymer substrates using a simple physical mask and a PVD equipment. The new process involves fewer process steps, it is cost effective and suitable for high volume industrial production. Current study suggests...

Bicolor Light-Emitting Diode Based on Zinc Oxide Nanorod Arrays and Poly(2-methoxy,5-octoxy)-1,4-phenylenevinylene

Science.gov (United States)

Song, Jizhong; He, Ying; Chen, Jie; Zhu, Di; Pan, Zhaodong; Zhang, Yaofei; Wang, Jun-An

2012-03-01

The current study reports a novel inorganic/organic light-emitting diode (LED), consisting of zinc oxide (ZnO) nanorod arrays and poly(2-methoxy, 5-octoxy)-1,4-phenylenevinylene (MOPPV). ZnO nanorod arrays passivated using polyacrylamide (PAM) with 70 nm diameter were successfully prepared by a simple polymer-assisted chemical method. Enhancement of the ZnO defect emission is caused by PAM passivation, as observed in photoluminescence spectra. Infrared absorption spectra reveal that PAM is chemically or physically adsorbed on the surfaces of ZnO nanorod arrays. The electroluminescence (EL) spectrum shows bluish light at 406 nm from ZnO transition emission, and light emission with center at 600 nm from exciton emission in MOPPV. The potential EL mechanism is electron transition to zinc vacancy in PAM/ZnO nanorod arrays, and exciton radiation luminescence in MOPPV film. This novel PAM/ZnO-MOPPV device may be helpful to promote development of multicolor LEDs.

Corrosion at the Polymer-Metal Interface in Artificial Seawater Solutions

Directory of Open Access Journals (Sweden)

Amelia M. Anderson-Wile

2012-01-01

Full Text Available Polymer components for liquid sealing applications are employed in a variety of potentially corrosive environments, such as seawater. Frequently, corrosion of the metal is found at or adjacent to the rubber-metal interface rather than at a noncontact area. The corrosion of different metal alloys (titanium, bronze, nickel, aluminum, 316 stainless steel, and 4130 steel in combination with rubber O-rings (Buna-N and EPDM of varying internal diameters and cross-sectional shapes in seawater over a period of four years is described herein. The corrosion of some metals (i.e., 4130 stainless steel was found to be accelerated through interaction with Buna-N rubber O-rings. Theories to account for corrosion at the polymer-metal interface, especially with respect to polymer composition and O-ring size and shape, are discussed.

Synthesis by plasma of polymer-metal materials

International Nuclear Information System (INIS)

Fernandez R, G.

2004-01-01

The objective of this work is the design of an experimental set-up to synthesize polymer- metal composites by plasma with versatility in the conditions of synthesis. The main components are a vacuum system capable to reach up to 10 -2 mbar and valves and accessories to control the pressure in the system. In order to generate the electrical discharges and the plasma, an electrical circuit with an inductive connection at 13.56 MHz of frequency was constructed. The electric field partially ionizes the reactor atmosphere where the polymer-metal composites were synthesized. The reactor has two metallic electrodes, one in front of the other, where the particles electrically charged collide against the electrodes producing ablation on them. The polymer-metal composites were synthesized by means of an inductive connection at 13.56 MHz. Aniline, 3-chlorine-ethylene and electrodes of silver (Ag) and copper (Cu) were used in a cylindrical reactor coupled with an external coil to generate glow discharges. The average pressures were 6.15 X 10 -1 and 5.2 X 10 -1 mbar for the synthesis of Poly aniline (P An) and Poly chloroethylene (PE-CI), respectively. The synthesis was performed during 60 and 180 minutes for P An and PE-CI, respectively. The polymers were formed, as films, with an average thickness of 6.42 μm for P An and, in the case of PE-CI, with an approximately growing rate of 14 ηm/W. The power in the syntheses was 30, 50, 70 and 90 W for P An and 50, 100, 120, 140 170, and 200 W for PE-CI. The characterization of the polymer-metal composites was done by energy dispersive spectroscopy to study the composition and the relation of the elements involved in the synthesis. The morphology of the films was studied by means of scanning electron microscopy. The infrared analysis (IR) was done to study the chemicals bonds and the structure of these polymers. Another important study in these materials was the behavior of the electrical conductivity (σ), which was complemented

Interfacial delamination in polymer coated metal sheet : a numerical-experimental study

NARCIS (Netherlands)

van den Bosch, M.

2007-01-01

An increasing amount of products are nowadays made of polymer coated metal sheet. Polymer coated metal has several advantages compared to traditionally Sn (tin) coated metal, such as costs savings and a more environmental friendly production process. Beverage and food cans are formed by draw-redraw

Sensitization of nano-porous ZnO photo-anode by a conjugated conducting polymer

Energy Technology Data Exchange (ETDEWEB)

Sirimanne, P.M. [Nano-Science Laboratory, Institute of Fundamental Studies, Hantana Road, Kandy (Sri Lanka); Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Premalal, E.V.A. [Nano-Science Laboratory, Institute of Fundamental Studies, Hantana Road, Kandy (Sri Lanka); Minoura, H. [Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan)

2011-01-15

Hybrid ZnO films are prepared via one-step electrochemical process. Extraction of organic component from hybrid films results tiny wires like ZnO columns perpendicular to the substrate. Visible light sensitive-conjugated polymer poly(2-methoxy-5-[2 ethylhexyloxy]-1-4-phenylenevinylene, MEH-PPV) was embedded in highly porous ZnO ceramic by a solvent vaporization technique. An attempt was made to fabricate polymer sensitized photovoltaic cell by coupling polymer embedded ZnO electrodes with an electrolyte. Maximum photovoltage of 490 mV is observed for the cell with the configuration of ZnO vertical stroke MEH-PPV vertical stroke I{sup -}/I{sub 3}{sup -} cell. (author)

21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

Influence of electron-donating polymer addition on the performance of polymer solar cells

International Nuclear Information System (INIS)

Kim, Youngkyoo; Shin, Minjung; Kim, Hwajeong; Ha, Youri; Ha, Chang-Sik

2008-01-01

Here we report the influence of electron-donating polymer addition on the performance of poly(3-hexylthiophene) (P3HT) : 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C 61 (PCBM) solar cells. Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) was chosen as the electron-donating polymer to improve the open circuit voltage (V OC ) due to its higher level of the highest occupied molecular orbital energy compared with P3HT. Results showed that the MDMO-PPV addition led to an improved V OC for ternary blend (P3HT : MDMO-PPV : PCBM) solar cells. In particular, after thermal annealing at 110 deg. C, the short circuit current density of ternary blend solar cells was greatly improved, close to that of comparative binary blend (P3HT : PCBM) solar cells.

21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended...

21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a two-part...

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

Subgap Absorption in Conjugated Polymers

Science.gov (United States)

Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

1991-01-01

Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

Sporadic colorectal polyps and mismatch repair proteins

Directory of Open Access Journals (Sweden)

Mahsa Molaei

2011-01-01

Full Text Available Background: Colorectal cancers often arise from benign polyps. Adenomatous polyps and serrated polyps progress step by step to adenocarcinoma and change into malignant cancers. Genetic and epigenetic changes have correlation with specific stages of polyp-adenocarcinoma progression and colorectal cancer histopathological changes. Aims: In this study we used immunohistochemistry (IHC staining in sporadic colorectal polyps to assay functional status of MLH1, MSH2, MSH6, and PMS2 proteins, to track genetic/epigenetic roles of this issue in our patients. Materials and Methods: In this cross-sectional study we assessed all patients who were admitted with sporadic colorectal polyps and underwent polypectomy in endoscopy department during 2004-2008. Result: IHC results were abnormal in 6.8% cases for MLH1, in 4.5% cases for MSH2, in 3% for MSH6, and in 4.8% for PMS2. In all cases with abnormal PMS2, MLH1 was also reported as abnormal. Same results were reported for abnormal MSH2, which is accompanied with abnormal MSH6 in all cases (P values < 0.001. There is no significant difference between IHC staining results, gender, dysplasia grade, adenomatous type, and invasion. On the other hand, there was significant difference between IHC staining results, polyp location, and mean age of patients. The same significant difference was between adenomatous polyps and serrated adenoma polyps by MLH1 and PMS2 (P values < 0.05. Conclusion: According to our findings, maybe MMR dysfunction is the cause of sporadic colorectal polyps in younger age and its increasing risk of dysplasia progression and malignancy progression is only in serrated adenoma. Sporadic polyps in left colon had a higher risk to progress to malignancies, and abnormal IHC staining for MLH1 and PMS2 in serrated polyps is much more than in other adenomatous polyps.

Giant fibrovascular polyp of esophagus

Directory of Open Access Journals (Sweden)

Ramakanth Sannidi

2016-01-01

Full Text Available Benign tumors of esophagus are uncommon and account for only 3% of all esophageal neoplasms. Fibrovascular polyps (FVP are rare intraluminal tumors of esophagus. They are composed of fibrous tissue, vascular structures and covered with normal Squamous epithelium. Here we present a case of a 45 yr old gentleman with progressive dysphagia since 3 months. UGI endoscopy showed a long, linear, compressible mass extending from cricoid area to gastro-esophageal junction (GEJ. Patient was operated, through cervical incision esophgectomy done and polyp of size 16 × 7 cm was removed. Histopathology of polyp was suggestive of fibrovascular polyp. Post surgery patient was asymptomatic and doing well.

Fluorescence and confocal imaging of mammalian cells using conjugated oligoelectrolytes with phenylenevinylene core

Energy Technology Data Exchange (ETDEWEB)

Milczarek, Justyna; Pawlowska, Roza; Zurawinski, Remigiusz; Lukasik, Beata; Garner, Logan E.; Chworos, Arkadiusz

2017-05-01

Over the last few years, considerable efforts are taken, in order to find a molecular fluorescent probe fulfilling their applicability requirements. Due to a good optical properties and affinity to biological structures conjugated oligoelectrolytes (COEs) can be considered as a promising dyes for application in fluorescence-based bioimaging. In this work, we synthetized COEs with phenylenevinylene core (PV-COEs) and applied as fluorescent membranous-specific probes. Cytotoxicity effects of each COE were probed on cancerous and non-cancerous cell types and little to no toxicity effects were observed at the high range of concentrations. The intensity of cell fluorescence following the COE staining was determined by the photoluminescence analysis and fluorescence activated cell sorting method (FACS). Intercalation of tested COEs into mammalian cell membranes was revealed by fluorescent and confocal microscopy colocalization with commercial dyes specific for cellular structures including mitochondria, Golgi apparatus and endoplasmic reticulum. The phenylenevinylene conjugated oligoelectrolytes have been found to be suitable for fluorescent bioimaging of mammalian cells and membrane-rich organelles. Due to their water solubility coupled with spontaneous intercalation into cells, favorable photophysical features, ease of cell staining, low cytotoxicity and selectivity for membranous structures, PV-COEs can be applied as markers for fluorescence imaging of a variety of cell types.

Photoactive Blends of Poly(para-phenylenevinylene) (PPV) with Methanofullerenes from a Novel Precursor : Photophysics and Device Performance

NARCIS (Netherlands)

Brabec, C.J.; Cravino, A.; Zerza, G.; Sariciftci, N.S.; Kiebooms, R.; Vanderzande, D.; Hummelen, J.C.

2001-01-01

Homogeneous blends of a processable methanofullerene, [6,6]-phenyl C61-butyric acid methyl ester (PCBM), with poly(para-phenylenevinylene) (PPV) synthesized using a novel nonionic precursor route were produced. These photoactive blends have been investigated by excited-state spectroscopy and by

Solid polymer electrolyte composite membrane comprising a porous support and a solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide

Science.gov (United States)

Liu, Han; Mittelsteadt, Cortney K; Norman, Timothy J; Griffith, Arthur E; LaConti, Anthony B

2015-02-24

A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a thin, rigid, dimensionally-stable, non-electrically-conducting support, the support having a plurality of cylindrical, straight-through pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores are unevenly distributed, with some or no pores located along the periphery and more pores located centrally. The pores are completely filled with a solid polymer electrolyte, the solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide. The solid polymer electrolyte may also be deposited over the top and/or bottom surfaces of the support.

Polymer-noble metal nanocomposites: Review

CSIR Research Space (South Africa)

Folarin, OM

2011-09-01

Full Text Available because of their multi-functionality, ease of process-ability, potential for large-scale manufacturing, significantly lighter than metals, ease of synthesis when compared to the oxide/noble metal multi-layers (Gass et al., 2006; Lee et al., 2003.... their easy aggregation arising from their high surface free energy (Lee et al., 2006). In the design of nanocomposites, one must consider the properties of the polymer matrix as well as the stability of the nanoparticles and more importantly...

Evaluation of patients with gastric polyps.

Science.gov (United States)

Olmez, Sehmus; Sayar, Suleyman; Saritas, Bunyamin; Savas, Ayla Yildiz; Avcioglu, Ufuk; Tenlik, Ilyas; Ozaslan, Ersan; Koseoglu, Hasan Tankut; Altiparmak, Emin

2018-01-01

The incidence of gastric polyps (GPs) greatly differs according to study populations and was found to be 0.33%-6.7% in various studies. The majority of GPs are composed of hyperplastic polyps (HPs), fundic gland polyps (FGPs), and adenomatous polyps (APs). Although APs have a high risk of malignant potential, sporadic FGPs have no malignant potential. Conversely, HPs have a low risk of malignant potential. It is not sufficient to perform a biopsy to identify the polyp type and the presence of dysplasia; thus, some polyps may require multiple biopsies or total excision. This retrospective study included patients with GPs or polypoid lesions found on esophagogastroscopy with polyp or malignant histology on biopsy at Ankara Numune Training and Research Hospital Endoscopy Unit between 2005 and 2011. In a series of 56.300 upper endoscopies, 192 patients (0.34%) were found to have GPs. Among the patients, 51 (26.6%) were men and 151 (73.4%) were women. The average age of the patients was 61.9±13.3 (14-90) years. The frequency of HPs, APs, and FGPs were 88%, 2.6%, and 1.6%, respectively. The size of the polyps was ≤1 cm in 137 (70%) patients. One polyp was determined in 141 (73.4%) patients. The most common localizations of polyps were the antrum and corpus. Endoscopic snare polypectomy was performed in 64 patients. One bleeding episode was observed, which required endoscopic treatment after ESP. In our study, the GP frequency was low (0.34%), whereas the frequency of HP maybe high due to the high frequency of Helicobacter pylori (HPy) infection in our country. The frequency of FGP is probably low due to the high frequency of HPy infection and the short-term use of proton-pump inhibitors.

Automatic polyp detection in colonoscopy videos

Science.gov (United States)

Yuan, Zijie; IzadyYazdanabadi, Mohammadhassan; Mokkapati, Divya; Panvalkar, Rujuta; Shin, Jae Y.; Tajbakhsh, Nima; Gurudu, Suryakanth; Liang, Jianming

2017-02-01

Colon cancer is the second cancer killer in the US [1]. Colonoscopy is the primary method for screening and prevention of colon cancer, but during colonoscopy, a significant number (25% [2]) of polyps (precancerous abnormal growths inside of the colon) are missed; therefore, the goal of our research is to reduce the polyp miss-rate of colonoscopy. This paper presents a method to detect polyp automatically in a colonoscopy video. Our system has two stages: Candidate generation and candidate classification. In candidate generation (stage 1), we chose 3,463 frames (including 1,718 with-polyp frames) from real-time colonoscopy video database. We first applied processing procedures, namely intensity adjustment, edge detection and morphology operations, as pre-preparation. We extracted each connected component (edge contour) as one candidate patch from the pre-processed image. With the help of ground truth (GT) images, 2 constraints were implemented on each candidate patch, dividing and saving them into polyp group and non-polyp group. In candidate classification (stage 2), we trained and tested convolutional neural networks (CNNs) with AlexNet architecture [3] to classify each candidate into with-polyp or non-polyp class. Each with-polyp patch was processed by rotation, translation and scaling for invariant to get a much robust CNNs system. We applied leave-2-patients-out cross-validation on this model (4 of 6 cases were chosen as training set and the rest 2 were as testing set). The system accuracy and sensitivity are 91.47% and 91.76%, respectively.

Growing perovskite into polymers for easy-processable optoelectronic devices

Science.gov (United States)

Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

2015-01-01

Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH3NH3PbI3 (MAPbI3) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition.

Inappropriate colonoscopic surveillance of hyperplastic polyps.

LENUS (Irish Health Repository)

Keane, R A

2011-11-15

Colonoscopic surveillance of hyperplastic polyps alone is controversial and may be inappropriate. The colonoscopy surveillance register at a university teaching hospital was audited to determine the extent of such hyperplastic polyp surveillance. The surveillance endoscopy records were reviewed, those patients with hyperplastic polyps were identified, their clinical records were examined and contact was made with each patient. Of the 483 patients undergoing surveillance for colonic polyps 113 (23%) had hyperplastic polyps alone on last colonoscopy. 104 patients remained after exclusion of those under appropriate surveillance. 87 of the 104 patients (84%) were successfully contacted. 37 patients (8%) were under appropriate colonoscopic surveillance for a significant family history of colorectal carcinoma. 50 (10%) patients with hyperplastic polyps alone and no other clinical indication for colonoscopic surveillance were booked for follow up colonoscopy. This represents not only a budgetary but more importantly a clinical opportunity cost the removal of which could liberate valuable colonoscopy time for more appropriate indications.

Metal-polymer composites comprising nanostructures and applications thereof

Science.gov (United States)

Wang, Hsing-Lin [Los Alamos, NM; Jeon, Sea Ho [Dracut, MA; Mack, Nathan H [Los Alamos, NM

2011-08-02

Metal-polymer composites, and methods of making and use thereof, said composites comprising a thermally-cured dense polyaniline substrate; an acid dopant; and, metal nanostructure deposits wherein the deposits have a morphology dependent upon the acid dopant.

Copper tolerance mediated by polyphosphate degradation and low-affinity inorganic phosphate transport system in Escherichia coli

OpenAIRE

Grillo-Puertas, Mariana; Schurig-Briccio, Lici Ariane; Rodríguez-Montelongo, Luisa; Rintoul, María Regina; Rapisarda, Viviana Andrea

2014-01-01

Background Metal tolerance in bacteria has been related to polyP in a model in which heavy metals stimulate the polymer hydrolysis, forming metal-phosphate complexes that are exported. As previously described in our laboratory, Escherichia coli cells grown in media containing a phosphate concentration >37 mM maintained an unusually high polyphosphate (polyP) level in stationary phase. The aim of the present work was to evaluate the influence of polyP levels as the involvement of low-affinity ...

Determinants of polyp Size in patients undergoing screening colonoscopy

Directory of Open Access Journals (Sweden)

Maisonneuve Patrick

2011-09-01

Full Text Available Abstract Background Pre-existing polyps, especially large polyps, are known to be the major source for colorectal cancer, but there is limited available information about factors that are associated with polyp size and polyp growth. We aim to determine factors associated with polyp size in different age groups. Methods Colonoscopy data were prospectively collected from 67 adult gastrointestinal practice sites in the United States between 2002 and 2007 using a computer-generated endoscopic report form. Data were transmitted to and stored in a central data repository, where all asymptomatic white (n = 78352 and black (n = 4289 patients who had a polyp finding on screening colonoscopy were identified. Univariate and multivariate analysis of age, gender, performance site, race, polyp location, number of polyps, and family history as risk factors associated with the size of the largest polyp detected at colonoscopy. Results In both genders, size of the largest polyp increased progressively with age in all age groups (P P Conclusions In both genders there is a significant increase in polyp size detected during screening colonoscopy with increasing age. Important additional risk factors associated with increasing polyp size are gender, race, polyp location, and number of polyps, with polyp multiplicity being the strongest risk factor. Previous family history of bowel cancer was not a risk factor.

Inflammatory fibroid polyp of sigmoid colon.

Science.gov (United States)

Lifschitz, O; Lew, S; Witz, M; Reiss, R; Griffel, B

1979-01-01

A case of inflammatory fibroid polyp of the sigmoid colon is presented. This is the eight case of this type of polyp in the colon and, to the best of our knowledge, the first one involving the sigmoid and producing intussusception. Symptomatology of the inflamed fibroid polyp in this part of the gut closely simulates gastrointestinal malignancy. The treatment is surgical excision of the polyp, or colonoscopic resection when it is possible. Intraoperative colonoscopy helps the surgeon to localize the lesion and to role out the existence of other lesions.

Adhesion along metal-polymer interfaces during plastic deformation

NARCIS (Netherlands)

van Tijum, R.; Vellinga, W. P.; De Hosson, J. Th. M.

In this paper a numerical study is presented that concentrates on the influence of the interface roughness that develops during plastic deformation of a metal, on the work of adhesion and on the change of interface energy upon contact with a glassy polymer. The polymer coating is described with a

Estimation of strength parameters of small-bore metal-polymer pipes

Science.gov (United States)

Shaydakov, V. V.; Chernova, K. V.; Penzin, A. V.

2018-03-01

The paper presents results from a set of laboratory studies of strength parameters of small-bore metal-polymer pipes of type TG-5/15. A wave method was used to estimate the provisional modulus of elasticity of the metal-polymer material of the pipes. Longitudinal deformation, transverse deformation and leak-off pressure were determined experimentally, with considerations for mechanical damage and pipe bend.

The Polyp Manager: a new tool for optimal polyp documentation during colonoscopy. A pilot study.

Science.gov (United States)

van de Meeberg, Maartje M.; Ouwendijk, Rob J. Th.; ter Borg, Pieter C. J.; van den Hazel, Sven J.; van de Meeberg, Paul C.

2016-01-01

Background and study aims: Conventional reporting of polyps is often incomplete. We tested the Polyp Manager (PM), a new software application permitting the endoscopist to document polyps in real time during colonoscopy. We studied completeness of polyp descriptions, user-friendliness and the potential time benefit. Patients and methods: In two Dutch hospitals colonoscopies were performed with PM (as a touchscreen endoscopist-operated device or nurse-operated desktop application). Completeness of polyp descriptions was compared to a historical group with conventional reporting (CRH). Prospectively, we compared user-friendliness (VAS-scores) and time benefit of the endoscopist-operated PM to conventional reporting (CR) in one hospital. Duration of colonoscopy and time needed to report polyps and provide a pathology request were measured. Provided that using PM does not prolong colonoscopy, the sum of the latter two was considered as a potential time-benefit if the PM were fully integrated into a digital reporting system. Results: A total of 144 regular colonoscopies were included in the study. Both groups were comparable with regard to patient characteristics, duration of colonoscopy and number of polyps. Using the PM did reduce incomplete documentation of the following items in CRH-reports: location (96 % vs 82 %, P = 0.01), size (95 % vs 89 %, P = 0.03), aspect (71 % vs 36 %, P < 0.001) and completeness of removal (61 % vs 37 %, P < 0.001). In the prospective study 23 PM-colonoscopies where compared to 28 CR-colonoscopies. VAS-scores were significantly higher in the endoscopist-operated PM group. Time to report was 01:27 ± 01:43 minutes (median + interquartile range) in the entire group (PM as CR), reflecting potential time benefit per colonoscopy. Conclusions: The PM is a user-friendly tool that seems to improve completeness of polyp reporting. Once integrated with digital reporting systems, it is probably time saving as

Sonographic diagnosis of juvenile polyps in children.

Science.gov (United States)

Zhang, Yao; Li, Shi-Xing; Xie, Li-Mei; Shi, Bo; Ju, Hao; Bai, Yu-Zuo; Zhang, Shu-Cheng

2012-09-01

The aim of this study was to assess the diagnostic value of ultrasonography for juvenile polyps in children and their sonographic characteristics. A retrospective analysis was performed of the ultrasound findings in 27 children who were diagnosed preoperatively with juvenile polyp within the intestinal tract by ultrasonography and then confirmed by colonoscopy, laparotomy and histopathology. The ultrasonic finding common to all polyps was an isolated intraluminal nodular or massive protrusion, associated with multiple mesh-like fluid areas of different sizes. In 25 children, surrounding pedicle-like low echoes of varying lengths were seen connecting with the polyps to form "mushroom" sign. The color Doppler showed abundant blood flow signals within all polyps and pedicles in a shape of a branch or an umbrella. For seven children with an intussusception, the polyp shadow was detected in the cervical part or interior of the intussusception. Ultrasonography is, thus, considered to be a feasible method for diagnosing intestinal juvenile polyp. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Energy-level alignment at metal-organic and organic-organic interfaces

NARCIS (Netherlands)

Veenstra, Sjoerd; Jonkman, H.T.

2003-01-01

This article reports on the electronic structure at interfaces found in organic semiconductor devices. The studied organic materials are C-60 and poly (para-phenylenevinylene) (PPV)-like oligomers, and the metals are polycrystalline Au and Ag. To measure the energy levels at these interfaces,

Metal-free, single-polymer device exhibits resistive memory effect

KAUST Repository

Bhansali, Unnat Sampatraj; Khan, Yasser; Cha, Dong Kyu; Almadhoun, Mahmoud N.; Li, Ruipeng; Chen, Long; Amassian, Aram; Odeh, Ihab N.; Alshareef, Husam N.

2013-01-01

All-polymer, write-once-read-many times resistive memory devices have been fabricated on flexible substrates using a single polymer, poly(3,4- ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). Spin-cast or inkjet-printed films of solvent-modified PEDOT:PSS are used as electrodes, while the unmodified or as-is PEDOT:PSS is used as the semiconducting active layer. The all-polymer devices exhibit an irreversible but stable transition from a low resistance state (ON) to a high resistance state (OFF) at low voltages caused by an electric-field-induced morphological rearrangement of PEDOT and PSS at the electrode interface. However, in the metal-PEDOT:PSS-metal devices, we have shown a metal filament formation switching the device from an initial high resistance state (OFF) to the low resistance state (ON). The all-PEDOT:PSS memory device has low write voltages (<3 V), high ON/OFF ratio (>10 3), good retention characteristics (>10 000 s), and stability in ambient storage (>3 months). © 2013 American Chemical Society.

Metal-free, single-polymer device exhibits resistive memory effect

KAUST Repository

Bhansali, Unnat Sampatraj

2013-12-23

All-polymer, write-once-read-many times resistive memory devices have been fabricated on flexible substrates using a single polymer, poly(3,4- ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). Spin-cast or inkjet-printed films of solvent-modified PEDOT:PSS are used as electrodes, while the unmodified or as-is PEDOT:PSS is used as the semiconducting active layer. The all-polymer devices exhibit an irreversible but stable transition from a low resistance state (ON) to a high resistance state (OFF) at low voltages caused by an electric-field-induced morphological rearrangement of PEDOT and PSS at the electrode interface. However, in the metal-PEDOT:PSS-metal devices, we have shown a metal filament formation switching the device from an initial high resistance state (OFF) to the low resistance state (ON). The all-PEDOT:PSS memory device has low write voltages (<3 V), high ON/OFF ratio (>10 3), good retention characteristics (>10 000 s), and stability in ambient storage (>3 months). © 2013 American Chemical Society.

Subgap absorption in conjugated polymers

Energy Technology Data Exchange (ETDEWEB)

Sinclair, M.; Seager, C.H. (Sandia National Labs., Albuquerque, NM (USA)); McBranch, D.; Heeger, A.J. (California Univ., Santa Barbara, CA (USA)); Baker, G.L. (Bell Communications Research, Inc., Red Bank, NJ (USA))

1991-01-01

Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination. 11 refs., 4 figs.

Use of Hydrophilic Insoluble Polymers in the Restoration of Metal-Contaminated Soils

Directory of Open Access Journals (Sweden)

Guiwei Qu

2009-01-01

Full Text Available To develop cost-effective techniques that contribute to phytostabilization of severely metal-contaminated soils is a necessary task in environmental research. Hydrophilic insoluble polymers have been used for some time in diapers and other hygienic products and to increase the water-holding capacity of coarse-textured soils. These polymers contain groups, such as carboxyl groups, that are capable of forming bonds with metallic cations, thereby decreasing their bioavailability in soils. The use of polyacrylate polymers as soil amendments to restore metal-contaminated soils has been investigated in the Technical University of Lisbon since the late nineties. Plant growth and plant nutrients concentrations, extractable levels of metals in soil, and soil enzyme activities were used to monitor the improvement in soil quality following the application of these polymers. In contaminated soils, hydrophilic insoluble polymers can create microcosms that are rich in water and nutrients (counterions but only contain small concentrations of toxic elements; the conditions of these microenvironments are favorable to roots and microorganisms. In this paper we described the most relevant information available about this topic.

Use of Hydrophilic Insoluble Polymers in the Restoration of Metal-Contaminated Soils

International Nuclear Information System (INIS)

Qu, G.; De Varennes, A.; Qu, G.

2010-01-01

To develop cost-effective techniques that contribute to phyto stabilization of severely metal-contaminated soils is a necessary task in environmental research. Hydrophilic insoluble polymers have been used for some time in diapers and other hygienic products and to increase the water-holding capacity of coarse-textured soils. These polymers contain groups, such as carboxyl groups, that are capable of forming bonds with metallic cations, thereby decreasing their bioavailability in soils. The use of polyacrylate polymers as soil amendments to restore metal-contaminated soils has been investigated in the Technical University of Lisbon since the late nineties. Plant growth and plant nutrients concentrations, extractable levels of metals in soil, and soil enzyme activities were used to monitor the improvement in soil quality following the application of these polymers. In contaminated soils, hydrophilic insoluble polymers can create microcosms that are rich in water and nutrients (counterions) but only contain small concentrations of toxic elements; the conditions of these micro environments are favorable to roots and microorganisms. In this paper we described the most relevant information available about this topic.

Removal and recovery of metal ions from process and waste streams using polymer filtration

International Nuclear Information System (INIS)

Jarvinen, G.D.; Smith, B.F.; Robison, T.W.; Kraus, K.M.; Thompson, J.A.

1999-01-01

Polymer Filtration (PF) is an innovative, selective metal removal technology. Chelating, water-soluble polymers are used to selectively bind the desired metal ions and ultrafiltration is used to concentrate the polymer-metal complex producing a permeate with low levels of the targeted metal ion. When applied to the treatment of industrial metal-bearing aqueous process streams, the permeate water can often be reused within the process and the metal ions reclaimed. This technology is applicable to many types of industrial aqueous streams with widely varying chemistries. Application of PF to aqueous streams from nuclear materials processing and electroplating operations will be described

Synthesis of new water-soluble metal-binding polymers: Combinatorial chemistry approach. 1997 mid-year progress report

International Nuclear Information System (INIS)

Smith, B.F.

1997-01-01

'The first objective of this research is to develop rapid discovery and optimization approaches to new water-soluble chelating polymers. A byproduct of the development approach will be the new, selective, and efficient metal-binding agents. The second objective is to evaluate the concept of using water and organic soluble polymers as new solid supports for combinatorial synthesis. The technology under development, Polymer Filtration (PF), is a technique to selectively remove or recover hazardous and valuable metal ions and radionuclides from various dilute aqueous streams. Not only can this technology be used to remediate contaminated soils and solid surfaces and treat aqueous wastes, it can also be incorporated into facilities as a pollution prevention and waste minimization technology. Polymer Filtration uses water-soluble metal-binding polymers to sequester metal ions in dilute solution. The water-soluble polymers have a sufficiently large molecular size that they can be separated and concentrated using commercial ultrafiltration technology. Water, small organic molecules, and unbound metals pass freely through the ultrafiltration membrane while concentrating the metal-binding polymer. The polymers can then be reused by changing the solution conditions to release the metal ions. The metal-ions are recovered in concentrated form for recycle or disposal using a diafiltration process. The water-soluble polymer can be recycled for further aqueous-stream processing. To advance Polymer Filtration technology to the selectivity levels required for DOE needs. fixture directions in Polymer Filtration must include rapid development, testing, and characterization of new metal-binding polymers. The development of new chelating molecules can be equated to the process of new drugs or new materials discovery. Thus, the authors want to build upon and adapt the combinatorial chemistry approaches developed for rapid molecule generation for the drug industry to the rapid

Synthesis of new water-soluble metal-binding polymers: Combinatorial chemistry approach. 1998 annual progress report

International Nuclear Information System (INIS)

Kurth, M.J.; Miller, R.B.; Sawan, S.; Smith, B.F.

1998-01-01

'(1) Develop rapid discovery and optimization approaches to new water-soluble chelating polymers for use in Polymer Filtration (PF) systems, and (2) evaluate the concept of using water and organic soluble polymers as new solid supports for combinatorial synthesis. Polymer Filtration (PF), which uses water-soluble metal-binding polymers to sequester metal ions in dilute solution with ultrafiltration (UF) to separate the polymers, is a new technology to selectively remove or recover hazardous and valuable metal ions. Future directions in PF must include rapid development, testing, and characterization of new metal-binding polymers. Thus, the authors are building upon and adapting the combinatorial chemistry approach developed for rapid molecule generation for the drug industry to the rapid development of new chelating polymers. The authors have focused on four areas including the development of: (1) synthetic procedures, (2) small ultrafiltration equipment compatible with organic- and aqueous-based combinatorial synthesis, (3) rapid assay techniques, and (4) polymer characterization techniques.'

New trends in the optical and electronic applications of polymers containing transition-metal complexes.

Science.gov (United States)

Liu, Shu-Juan; Chen, Yang; Xu, Wen-Juan; Zhao, Qiang; Huang, Wei

2012-04-13

Polymers containing transition-metal complexes exhibit excellent optical and electronic properties, which are different from those of polymers with a pure organic skeleton and combine the advantages of both polymers and metal complexes. Hence, research about this class of polymers has attracted more and more interest in recent years. Up to now, a number of novel polymers containing transition-metal complexes have been exploited, and significant advances in their optical and electronic applications have been achieved. In this article, we summarize some new research trends in the applications of this important class of optoelectronic polymers, such as chemo/biosensors, electronic memory devices and photovoltaic devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polymer-supported reagents with enhanced metal ion recognition: Application to separations science

International Nuclear Information System (INIS)

Alexandratos, S.D.

1993-01-01

The design and development of polymer-supported reagents with ever-increasing specificities for targeted metal ions remains an important areas of research. The need for efficient separation schemes for both ions and molecules has been outlined in a report by the National Research Council (King) and will gain increased emphasis as environmental restoration is pursued. Polymer-supported reagents are unique in their ability to be applied in an environmentally benign manner to a host of challenges. Such reagents, in the form of beads, can be applied to continuous separation processes ranging from the removal of metal ions in water to the recovery of medicinal drugs produced through biotechnological means. The application of polymer-supported reagents to metal ion separations still requires developing a fundamental understanding of ligand-metal interactions, the role of the polymer in those interactions, and the methods of synthesizing such polymeric reagents in a readily applicable form. Ion exchange resins with sulfonic acid ligands are the prototypical polymer-supported reagents, and their properties have been exhaustively studied (Helfferich). The high acidity of the sulfonic acid group, however, precludes much selectivity, and it displays a very limited range of reaction free energy values with different metal ions (Boyd et al.). The carboxylic acid ligand, present in the acrylate resins, is more selective, though its weak acidity requires relatively high pH solutions for it to be effective. Research has thus been focused on the preparation of polymer-supported reagents with high levels of specificity for targeted metal ions

Frequency of Thyroid Nodules among Patients with Colonic Polyps

Directory of Open Access Journals (Sweden)

Cevdet Duran

2012-01-01

Full Text Available Aim. Colonic polyps and thyroid nodules are common diseases and their frequency increases with age. In the literature, there is no study investigating the coexistence of colonic polyps and thyroid nodules. Therefore, this study was designed to investigate thyroid nodule prevalence in patients with colonic polyps. Material and Methods. Sixty-six patients with colonic polyps and 146 patients without colonic polyps enrolled into the study. Age and sex matched control group was composed from patients without colonic polyps. Colonoscopic examinations, thyroid ultrasonographies were performed in all patients, and TSH were measured. Results. Male/female ratio in polyp and control groups were 40/26 versus 68/78, respectively (P=0.058. Mean ages were similar in both groups (53.3±11.4 versus, 51.8±11.4, P=0.373. Thyroid nodule was detected in 44 (66.7% patients with polyps and in 61 (41.8% controls (P=0.001. Patients with adenomatous polyps had 5 or more thyroid nodules compared to patients with hyperplastic polyps (P=0.03. Thyroid nodules were more prevalent among patients aged 50 or older compared to 50 years or less (P=0.023. Conclusion. Thyroid nodules were detected more common in patients with colonic polyps. Further studies are needed to clarify this coexistence.

Positron beam analysis of polymer/metal interfaces under stress

NARCIS (Netherlands)

Escobar Galindo, R.; van Veen, A.; Garcia, A.A.; Schut, H.; de Hosson, J.T.M.; Triftshauser, W; Kogel, G; Sperr, P

2001-01-01

The polymers Epoxy and Poly(Methyl MethAcrylate) spin coated on Interstitial Free (IF) steel were subjected to external stresses and studied using the Delft Variable Energy Positron (VEP) beam facility. The polymer/metal interface was identified using an S-W map. After tensile experiments vacancy

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a two-part...

Chemical metallization of KMPR photoresist polymer in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Zeb, Gul [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Mining & Materials Engineering, McGill University, 3610,University Street, Montreal, QC, H3A 0C5 (Canada); Duong, Xuan Truong [Department of Mechanical Engineering, Ecole polytechnique de Montréal, Montréal, QC, H3C 3T5 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh [Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Salimy, Siamak [ePeer Review LLC, 145 Pine Haven Shores Rd, Suite 1000-X, Shelburne, VT 05482 (United States); Le, Xuan Tuan, E-mail: xuantuan.le@teledyne.com [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam)

2017-06-15

Highlights: • Electroless deposition of Ni-B film on KMPR photoresist polymer insulator with excellent adhesion has been achieved. • This metallization has been carried out in aqueous solutions at low temperature. • Polyamine palladium complexes grafts serve as seeds for the electroless plating on KMPR. • This electroless metallization process is simple, industrially feasible, chromium-free and environment-friendly. - Abstract: While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

Charge Injection and Transport in Metal/Polymer Chains/Metal Sandwich Structure

International Nuclear Information System (INIS)

Hai-Hong, Li; Dong-Mei, Li; Yuan, Li; Kun, Gao; De-Sheng, Liu; Shi-Jie, Xie

2008-01-01

Using the tight-binding Su–Schrieffer–Heeger model and a nonadiabatic dynamic evolution method, we study the dynamic processes of the charge injection and transport in a metal/two coupled conjugated polymer chains/metal structure. It is found that the charge interchain transport is determined by the strength of the electric field and the magnitude of the voltage bias applied on the metal electrode. The stronger electric field and the larger voltage bias are both in favour of the charge interchain transport. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Enhanced Nanotribology and Optimal Self-lubrication in Novel Polymer-Metal Composites

Science.gov (United States)

Seam, Alisha; Brostow, Witold; Olea-Mejia, Oscar

2006-10-01

Cheaper to produce, light-weight polymeric materials with improved micro and nano-scale tribological characteristics ar gradually replacing the heavier metals in gears, cams, ball-bearings, chains, and other critical machine components which operate under high stress, experience substantial sliding friction and wear, and require external lubrication regimes. Application of such high-performance synthetic materials in a whole range of machinery, manufacturing, aerospace and transportation industries would produce far reaching economic, energy conservation and environmental benefits. This paper devises and investigates a novel and previously untested method of developing self-lubricating and wear-resistant polymer based materials (PBMs) by blending a polymer with small proportions of a metallic additive. Tribological experiments establish that as increasing proportions of the metallic additive Iron (Fe) are added to the polymeric base polyethylene (PE), the friction and wear of the resulting composite (PE-Fe) experiences significant decline until an optimal value of 3 to 5 % Iron and then stabilize. Theoretical analysis reveals this phenomenon to likely be a result of the nano-structural formation of a lubricating oxide layer on surface of the polymer-metal composite. Furthermore, the oxide layer prevented significant degradation of the viscoelastic scratch-recovery of the base polymer, even with 10 percent metal additive (Fe) in the composite samples.

Application of β-cyclodextrin polymers in separation of metal ions

International Nuclear Information System (INIS)

Kozlowski, C.A.; Kozlowska, J.

2006-01-01

In the present work the competitive transport of Cu(II), Co(II), Ni(II) and Zn(II) ions through the plasticized immobilized membranes was studied. β-cyclodextrin (β-CD) polymers have been used as macrocyclic ligands for separation of metal ions from dilute aqueous solutions by ion exchange methods, i.e. transport across polymer inclusion membranes and ion flotation process. β-CD polymers were prepared by cross-linking β-CD with alkenyl (nonenyl) succinic anhydride derivatives, phtalic and 3-nitrophtalic anhydride in anhydrous N,N-dimethylformamide (DMF) resulting in formation of Polymer A, B or C, respectively. In he case of cooper(II) flotation results obtained with the use of nonylphenol polyoxyethyl glycol ether as an non-anionic surfactant and β-CD polymers as complexation agent, show that the removal of metal decreases with higher molecular mass of β-CD polymers linked by phtalic or 3-nitrophtalic anhydrides. For both derivatives with pH increase the copper(II) removed increase. The highest flotation removal, i.e. 93% is observed for β-CD polymers synthesized at 100 o C with molar ratio CD : NaH : 3-nitrophtalic anhydride equal to 1 : 7 : 7

POLYMER COMPOSITE FILMS WITH SIZE-SELECTED METAL NANOPARTICLES FABRICATED BY CLUSTER BEAM TECHNIQUE

DEFF Research Database (Denmark)

Ceynowa, F. A.; Chirumamilla, Manohar; Popok, Vladimir

2017-01-01

Formation of polymer films with size-selected silver and copper nanoparticles (NPs) is studied. Polymers are prepared by spin coating while NPs are fabricated and deposited utilizing a magnetron sputtering cluster apparatus. The particle embedding into the films is provided by thermal annealing...... after the deposition. The degree of immersion can be controlled by the annealing temperature and time. Together with control of cluster coverage the described approach represents an efficient method for the synthesis of thin polymer composite layers with either partially or fully embedded metal NPs....... Combining electron beam lithography, cluster beam deposition and thermal annealing allows to form ordered arrays of metal NPs on polymer films. Plasticity and flexibility of polymer host and specific properties added by coinage metal NPs open a way for different applications of such composite materials...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint... of a knee joint. The device limits translation or rotation in one or more planes and has components...

Photoluminescence studies on porous silicon/polymer heterostructure

International Nuclear Information System (INIS)

Mishra, J.K.; Bhunia, S.; Banerjee, S.; Banerji, P.

2008-01-01

Hybrid devices formed by filling porous silicon with MEH-PPV or poly [2-methoxy-5(2-ethylhexyloxy-p-phenylenevinylene)] have been investigated in this work. Analyses of the structures by scanning electron microscopy (SEM) demonstrated that the porous silicon layer was filled by the polymer with no significant change of the structures except that the polymer was infiltrated in the pores. The photoluminescence (PL) of the structures at 300 K showed that the emission intensity was very high as compared with that of the MEH-PPV films on different substrates such as crystalline silicon (c-Si) and indium tin oxide (ITO). The PL peak in the MEH-PPV/porous silicon composite structure is found to be shifted towards higher energy in comparison with porous silicon PL. A number of possibilities are discussed to explain the observations

Welding of a metal-polymer laminate

NARCIS (Netherlands)

Gower, H.L.

2007-01-01

The purpose of this work is to investigate the weldability of a metal polymer sandwich structure. The welding of the sandwich material proceeds first by welding of the skin layer. The material selected for this research is Steelite, a sandwich structure developed by Corus, with 0.12 mm thick mild

A Hierarchically Porous Hypercrosslinked and Novel Quinone based Stable Organic Polymer Electrode for Lithium-Ion Batteries

International Nuclear Information System (INIS)

Ahmad, Aziz; Meng, Qinghai; Melhi, Saad; Mao, Lijuan; Zhang, Miao; Han, Bao-Hang; Lu, Kun; Wei, Zhixiang

2017-01-01

Highlights: •A novel hypercrosslinked Poly-Pillar[5]quinone (Poly-P5Q) polymer has been prepared and applied as electrode material in Li-ion batteries. •The novel synthetic route of Poly-P5Q was introduced by the oxidation of Poly-Dimethoxypillar[5]arene. •A Friedel-Crafts reaction was employed to prepare a novel Poly-P5Q as organic cathode material for lithium-ion batteries. -- Abstract: In the recent years, organic electrode materials have attracted tremendous attention and becoming promising electrode candidates for the green and sustainable lithium-ion batteries. A novel hypercrosslinked Poly-Pillar[5]quinone (Poly-P5Q) polymer was prepared and applied as electrode material in Li-ion batteries. Poly-P5Q is the oxidized form of Poly-Dimethoxypillar[5]arene (Poly-DMP5A) which was obtained from the condensation of dimethoxypillar[5]arene and formaldehyde dimethyl acetal using Friedel-Crafts reaction. The prepared materials were characterized by 13 C solid state NMR, FTIR, SEM, EDX and TGA analysis. The Poly-P5Q cathode showed an initial discharge capacity up to 105 mAh g −1 whereas it retained 82.3% of its initial discharge capacity after 100 charge-discharge cycles at a current speed of 100 mA g −1 in the potential window between 1.75 to 3.25 V. In future, research in this direction will provide great insight for the development of novel polymers from various small organic molecules as a stable and high performance electrode materials for green lithium-ion batteries.

Chemical and structural changes at the ABS polymer-copper metal interface

NARCIS (Netherlands)

Kisin, S.; Scaltro, F.; Malanowski, P.; Varst, van der P.G.T.; With, de G.

2007-01-01

Creating oxygen containing moieties (hydroxyl or carbonyl) on polymer substrate surfaces is known to increase the adhesion strength of polymers to metals. However, we noticed adhesion increase with time even though no pre- or post-treatment of the polymer substrate was done. In the case of sputtered

Conductance enhancement of InAs/InP heterostructure nanowires by surface assembly of oligo-phenylenevinylene molecular wires

Energy Technology Data Exchange (ETDEWEB)

Schukfeh, Muhammed Ihab; Szwajca, Anna; Hansen, Allan; Tornow, Marc [Institut fuer Halbleitertechnik, TU Braunschweig (Germany); Storm, Kristian; Thelander, Claes; Samuelson, Lars [Lund University, Solid State Physics (Sweden); Soendergaard, Roar; Krebs, Frederik C. [Risoe DTU, Technical University of Denmark (Denmark); Hinze, Peter; Weimann, Thomas [PTB, Braunschweig (Germany)

2011-07-01

The direct combination of organic molecules with semiconductor nanostructures provides an appealing approach towards possible future nanoelectronic systems. In this context, indium-arsenide is a material of particular interest due to the presence of an electron inversion layer at the surface. We have prepared 50 nm diameter InAs nanowires comprising a 5 nm long InP segment, and contacted them by Ti/Au metallic leads on a planar Si/Si-oxide substrate. Electronic transport measurements at 77 K confirmed the presence of the potential barrier of the InP segment. After investigation of the assembly of 12 nm long, dithiolated oligo-phenylenevinylene (OPV) derivative molecules from solution onto planar InAs surfaces the same recipe was applied to the InAs/InP nanowires, which led to a pronounced, non-linear I-V characteristic, with significantly increased currents of up to 1 {mu}A at 1 V bias, for a back-gate voltage of 3 V. We attribute this effect to the OPV molecules tethered to the nanowire surface, thereby increasing the surface conductance across the InP barrier.

A combined theoretical and experimental study of the polymer inter-chain structure in poly(phenylene vinylene) derivatives

International Nuclear Information System (INIS)

Sumpter, B G; Drummond, M L; Shelton, W A; Valeev, E F; Barnes, M D

2008-01-01

The structures and photophysical properties of single molecule MEH-PPV (2-methoxy-5-(2'-ethyl-hexyloxy)-p-phenylenevinylene) and CN-PPV (2,5,2' ,5'-tetrahexyloxy-7,8'-dicyano-p-phenylenevinylene) nanoparticles are investigated using electronic structure theory and high resolution fluorescence experiments. It is shown that electron withdrawing substituents, such as CN, on the vinyl group of the PPV polymer backbone cause substantial change in the π electronic structure which subsequently decreases the inter-chain distance. Not only does CN-PPV have a smaller inter-chain separation compared to MEH-PPV, but also an increased binding energy and more efficient charge transport (carrier mobility) due to larger electronic coupling (charge transfer integrals). These changes help explain the enhanced luminescence quantum yield, photo-stability, and lifetime for CN-PPV versus MEH-PPV observed in experimental high resolution fluorescence imaging of individual single molecule nanoparticles

Adaptive neuro-fuzzy control of ionic polymer metal composite actuators

International Nuclear Information System (INIS)

Thinh, Nguyen Truong; Yang, Young-Soo; Oh, Il-Kwon

2009-01-01

An adaptive neuro-fuzzy controller was newly designed to overcome the degradation of the actuation performance of ionic polymer metal composite actuators that show highly nonlinear responses such as a straightening-back problem under a step excitation. An adaptive control algorithm with the merits of fuzzy logic and neural networks was applied for controlling the tip displacement of the ionic polymer metal composite actuators. The reference and actual displacements and the change of the error with the electrical inputs were recorded to generate the training data. These data were used for training the adaptive neuro-fuzzy controller to find the membership functions in the fuzzy control algorithm. Software simulation and real-time experiments were conducted by using the Simulink and dSPACE environments. Present results show that the current adaptive neuro-fuzzy controller can be successfully applied to the reliable control of the ionic polymer metal composite actuator for which the performance degrades under long-time actuation

Nasal polyps

Science.gov (United States)

... shrink polyps, and can reduce swelling and nasal congestion. The effect lasts a few months in most ... this procedure, your doctor uses a thin, lighted tube with instruments at the end. The tube is ...

Liquid metals as electrodes in polymer light emitting diodes

NARCIS (Netherlands)

Andersson, G.G.; Gommans, H.H.P.; Denier van der Gon, A.W.; Brongersma, H.H.

2003-01-01

We demonstrate that liquid metals can be used as cathodes in light emitting diodes (pLEDs). The main difference between the use of liquid cathodes and evaporated cathodes is the sharpness of the metal–polymer interface. Liquid metal cathodes result in significantly sharper metal–organic interfaces

Synthesis by plasma of polymer-metal materials; Sintesis por plasma de materiales polimero-metal

Energy Technology Data Exchange (ETDEWEB)

Fernandez R, G

2004-07-01

The objective of this work is the design of an experimental set-up to synthesize polymer- metal composites by plasma with versatility in the conditions of synthesis. The main components are a vacuum system capable to reach up to 10{sup -2} mbar and valves and accessories to control the pressure in the system. In order to generate the electrical discharges and the plasma, an electrical circuit with an inductive connection at 13.56 MHz of frequency was constructed. The electric field partially ionizes the reactor atmosphere where the polymer-metal composites were synthesized. The reactor has two metallic electrodes, one in front of the other, where the particles electrically charged collide against the electrodes producing ablation on them. The polymer-metal composites were synthesized by means of an inductive connection at 13.56 MHz. Aniline, 3-chlorine-ethylene and electrodes of silver (Ag) and copper (Cu) were used in a cylindrical reactor coupled with an external coil to generate glow discharges. The average pressures were 6.15 X 10{sup -1} and 5.2 X 10{sup -1} mbar for the synthesis of Poly aniline (P An) and Poly chloroethylene (PE-CI), respectively. The synthesis was performed during 60 and 180 minutes for P An and PE-CI, respectively. The polymers were formed, as films, with an average thickness of 6.42 {mu}m for P An and, in the case of PE-CI, with an approximately growing rate of 14 {eta}m/W. The power in the syntheses was 30, 50, 70 and 90 W for P An and 50, 100, 120, 140 170, and 200 W for PE-CI. The characterization of the polymer-metal composites was done by energy dispersive spectroscopy to study the composition and the relation of the elements involved in the synthesis. The morphology of the films was studied by means of scanning electron microscopy. The infrared analysis (IR) was done to study the chemicals bonds and the structure of these polymers. Another important study in these materials was the behavior of the electrical conductivity ({sigma

Radioisotope albedo method for measuring thickness of polymers coatings on metal basis

International Nuclear Information System (INIS)

Kapranov, B.I.; Myakin'kova, L.V.; Shaverin, V.A.

1986-01-01

Theoretical analysis of albedo thickness measuring of polymer coating-metal composite has been made and experimental studies of the range of tested thicknesses of polymer coating when different metal bases and radiation sources are used have been conducted. It is shown that the thickness of polymer coating on metal can be measured using backscattered γ-radiation in the energy range of 20-120 keV at the error 0.15-0.8 mm, at that, for thickness up to 23 mm the use of 147 Pm isotope can be defined as the optimum one; for thicknesses up to 40 mm 241 Am should be used; at thicknesses up to 60 mm - 57 Co. The AGAT-1 albedo gamma thickness gage, designed for measuring thickness of fiber glass coating up to 20 mm on metal base, is described

A Rare Complication of Hyperplastic Gastric Polyp

Directory of Open Access Journals (Sweden)

Suresh Kumar Nayudu

2013-01-01

Full Text Available Hyperplastic gastric polyps are incidentally diagnosed during upper gastrointestinal endoscopy. They are known to cause gastric outlet obstruction and chronic blood loss leading to iron deficiency anemia. However, hyperplastic gastric polyp presenting as acute severe upper gastrointestinal bleeding is very rare. To the best of our knowledge, there have been two cases of hyperplastic gastric polyps presenting as acute gastrointestinal bleeding in the medical literature. We present a case of a 56-year-old African American woman who was admitted to our hospital with symptomatic anemia and sepsis. The patient developed acute upper gastrointestinal bleeding during her hospital stay. She underwent emergent endoscopy, but bleeding could not be controlled. She underwent emergent laparotomy and wedge resection to control the bleeding. Biopsy of surgical specimen was reported as hyperplastic gastric polyp. We recommend that physicians should be aware of this rare serious complication of hyperplastic gastric polyps as endoscopic polypectomy has diagnostic and therapeutic benefits in preventing future complications including bleeding.

ETIOLOGICAL FACTORS FOR VOCAL FOLD POLYP FORMATION

Directory of Open Access Journals (Sweden)

DAŠA GLUVAJIĆ

2016-05-01

Full Text Available Background: Vocal fold polyp is one of the most common causes for hoarseness. Many different etiological factors contribute to vocal fold polyp formation. The aim of the study was to find out whether the etiological factors for polyp formation have changed in the last 30 years.Methods: Eighty-one patients with unilateral vocal fold polyp were included in the study. A control group was composed of 50 volunteers without voice problems who matched the patients by age and gender. The data about etiological factors and the findings of phoniatric examination were obtained from the patients' medical documentation and from the questionnaires for the control group. The incidence of etiological factors was compared between the two groups. The program SPSS, Version 18 was used for statistical analysis.Results: The most frequent etiological factors were occupational voice load, GER, allergy and smoking. In 79% of patients 2 – 6 contemporary acting risk factors were found. Occupational voice load (p=0,018 and GER (p=0,004 were significantly more frequent in the patients than in the controls. The other factors did not significantly influence the polyp formation.Conclusions: There are several factors involved simultaneously in the formation of vocal fold polyps both nowadays and 30 years ago. Some of the most common factors remain the same (voice load, smoking, others are new (GER, allergy, which is probably due to the different lifestyle and working conditions than 30 years ago. Occupational voice load and GER were significantly more frequently present in the patients with polyp than in the control group. Regarding the given results it is important to instruct workers with professional vocal load about etiological factors for vocal fold polyp formation.

Epidemiology of goblet cell and microvesicular hyperplastic polyps.

Science.gov (United States)

Qazi, Taha M; O'Brien, Michael J; Farraye, Francis A; Gould, Ryan W; Chen, Clara A; Schroy, Paul C

2014-12-01

Serrated polyps compromise both typical hyperplastic polyps as well as sessile serrated adenomas and dysplastic serrated polyps. Hyperplastic polyps exhibit two histological patterns: microvesicular hyperplastic polyps (MVHPs) and goblet cell hyperplastic polyps (GCHPs). MVHPs and GCHPs differ in their molecular signature. MVHPs have been frequently found to have the BRAF(V600E) mutation as well as aberrant methylation. In contrast, GCHPs have been associated with the KRAS mutation (KRAS-mut), which are infrequently seen in dysplastic serrated sessile adenomas. The particular risk factors that are associated with development of the types of hyperplastic polyps have not been previously studied. The purpose of this study is to characterize the associations between particular risk factors and the development of goblet cell or microvesicular hyperplastic polyps. We conducted a cross-sectional analysis of 3,543 asymptomatic, mostly average risk patients 50 and 79 years of age undergoing open-access screening colonoscopy between March 2005 and January 2012. Each patient was given a survey regarding 25 reputed risk factors for colorectal neoplasia and the responses were correlated with findings at colonoscopy. Associations between putative risk factors for colorectal neoplasia and MVHPs and GSHPs were examined using multiple logistic regression. MVHPS and GCHPs were identified in 5.3% and 8.7% of patients, respectively. The results of the statistical analysis indicate that a history of smoking greater than 20 years is associated with an increased risk of MVHPs (P30 kg/m(2) was also associated with the presence of MVHP at colonoscopy (PGCHP at colonoscopy in blacks. The study suggests that the development of the distinct histological types of hyperplastic polyps are associated with distinct modifiable and non-modifiable lifestyle factors.

Immobilization of metals in contaminated soils using natural polymer-based stabilizers.

Science.gov (United States)

Tao, Xue; Li, Aimin; Yang, Hu

2017-03-01

Three low-cost natural polymer materials, namely, lignin (Ln), carboxymethyl cellulose, and sodium alginate, were used for soil amendment to immobilize lead and cadmium in two contaminated soil samples collected from a mining area in Nanjing, China. The remediation effects of the aforementioned natural polymers were evaluated by toxicity characteristic leaching procedure (TCLP) and sequential extractions. The stabilizers could lower the bioavailability of Pb and Cd in the contaminated soils, and the amount of the exchangeable forms of the aforementioned two metals were reduced evidently. TCLP results showed that the leaching concentrations of Pb and Cd were decreased by 5.46%-71.1% and 4.25%-49.6%, respectively, in the treated soils. The contents of the organic forms of the two metals both increased with the increase in stabilizer dose on the basis of the redistribution of metal forms by sequential extractions. These findings were due to the fact that the abundant oxygen-containing groups on the polymeric amendments were effective in chelating and immobilizing Pb and Cd, which have been further confirmed from the metal adsorptions in aqueous solutions. Moreover, Ln achieved the greatest effect among the three polymers under study because of the former's distinct three-dimensional molecular structure, showing the preferential immobilization of Pb over Cd in soils also. Thus, the above-mentioned natural polymers hold great application potentials for reducing metal ion entry into the food chain at a field scale. Copyright © 2016 Elsevier Ltd. All rights reserved.

“High-Throughput” Evaluation of Polymer-Supported Triazolic Appendages for Metallic Cations Extraction

Directory of Open Access Journals (Sweden)

Riadh Slimi

2015-03-01

Full Text Available The aim of this work was to find and use a low-cost high-throughput method for a quick primary evaluation of several metal extraction by substituted piperazines appendages as chelatants grafted onto Merrifield polymer using click-chemistry by the copper (I-catalyzed Huisgen’s reaction (CuAAC The polymers were tested for their efficiency to remove various metal ions from neutral aqueous solutions (13 cations studied: Li+, Na+, K+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Cd2+, Ba2+, Ce3+, Hg+ and Pb2+ using the simple conductimetric measurement method. The polymers were found to extract all metals with low efficiencies ≤40%, except for Fe3+ and Hg+, and sometimes Pb2+. Some polymers exhibited a selectively for K+, Cd2+ and Ba2+, with good efficiencies. The values obtained here using less polymer, and a faster method, are in fair correspondence (average difference ±16% with another published evaluation by atomic absorption spectroscopy (AAS.

21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial (uni-compartmental) metal... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer porous-coated...

Insight into the Broad Field of Polymer Nanocomposites: From Carbon Nanotubes to Clay Nanoplatelets, via Metal Nanoparticles

Directory of Open Access Journals (Sweden)

Cristina Stefanescu

2009-11-01

Full Text Available Highly ordered polymer nanocomposites are complex materials that display a rich morphological behavior owing to variations in composition, structure, and properties on a nanometer length scale. Metal-polymer nanocomposite materials are becoming more popular for applications requiring low cost, high metal surface areas. Catalytic systems seem to be the most prevalent application for a wide range of metals used in polymer nanocomposites, particularly for metals like Pt, Ni, Co, and Au, with known catalytic activities. On the other hand, among the most frequently utilized techniques to prepare polymer/CNT and/or polymer/clay nanocomposites are approaches like melt mixing, solution casting, electrospinning and solid-state shear pulverization. Additionally, some of the current and potential applications of polymer/CNT and/or polymer/clay nanocomposites include photovoltaic devices, optical switches, electromagnetic interference (EMI shielding, aerospace and automotive materials, packaging, adhesives and coatings. This extensive review covers a broad range of articles, typically from high impact-factor journals, on most of the polymer-nanocomposites known to date: polymer/carbon nanotubes, polymer/metal nanospheres, and polymer/clay nanoplatelets composites. The various types of nanocomposites are described form the preparation stages to performance and applications. Comparisons of the various types of nanocomposites are conducted and conclusions are formulated.

Polymer-metal hybrid transparent electrodes for flexible electronics

Science.gov (United States)

Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

2015-03-01

Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of ‘polymer-metal hybrid electrodes’ with high-performance properties, including a bending radius 95% and a sheet resistance solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides.

Inverse gold photonic crystals and conjugated polymer coated opals for functional materials

Energy Technology Data Exchange (ETDEWEB)

Landon, P.B.; Gutierrez, Jose; Ferraris, John P.; Martinez, I.L.; Giridharagopal, Rajiv; Wu, Y.-C.; Lee, Sergey; Parikh, Kunjal; Gillespie, Jessica; Ussery, Geoffrey; Karimi, Behzad; Baughman, Ray; Zakhidov, Anvar; Glosser, R

2003-10-01

Inverse gold photonic crystals templated from synthetic opals with a face centered cubic (FCC) crystal lattice were constructed by heat converting gold chloride to metallic gold. Tetrahedral formations constructed of alternating large and small octahedrons oriented in the zinc sulfide structure were created by controlling the infiltration of gold chloride. Silica spheres were coated with polyanilinesulfonic acid, polypyrrole, poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and 5 nm colloidal gold. Ordinary yeast cells were coated with polyanilinesulfonic acid, polypyrrole and 5 nm colloidal gold. Spheres coated with MEH-PPV were dispersed in H{sub 2}O and coated with polyelectrolytes which recharged and sterically stabilized the colloidal surfaces. The recharged spheres self-assembled by sedimentation with a FCC crystalline lattice possessing 500 {mu}m wide and 1 mm long crystallites. Silica spheres with diameters as large as 1500 {mu}m were self-assembled along the [1 0 0] direction of the FCC crystal lattice. Opals infiltrated with gold and opals constructed from polymer coated spheres were co-infiltrated with polypropylene yielding inverse polypropylene composite photonic crystals.

21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint... replace a hip joint. The device prevents dislocation in more than one anatomic plane and has components...

Disulfide polymer grafted porous carbon composites for heavy metal removal from stormwater runoff

DEFF Research Database (Denmark)

Ko, Dongah; Mines, Paul D.; Jakobsen, Mogens Havsteen

2018-01-01

The emerging concern of heavy metal pollution derived from stormwater runoff has triggered a demand for effective heavy metal sorbents. To be an effective sorbent, high affinity along with rapid sorption kinetics for environmental relevant concentrations of heavy metals is important. Herein, we...... have introduced a new composite suitable for trace metal concentration removal, which consists of cheap and common granular activated carbon covered with polymers containing soft bases, thiols, through acyl chlorination (DiS-AC). Material characterization demonstrated that the polymer was successfully...

Strategies for incorporation of polymer photovoltaics into garments and textiles

DEFF Research Database (Denmark)

Krebs, Frederik C; Biancardo, M.; Winther-Jensen, B.

2006-01-01

device as a structural element. The total area of the device on PET was typically much smaller than the active area due to the decorative design of the aluminium electrode. Elaborate integration of the photovoltaic device into the textile material involved the lamination of a polyethylene (PE) film onto......The incorporation of polymer photovoltaics into textiles was demonstrated following two different strategies. Simple incorporation of a polyethyleneterphthalate (PET) substrate carrying the polymer photovoltaic device prepared by a doctor blade technique necessitated the use of the photovoltaic...... a suitably transparent textile material that was used as substrate. Plasma treatment of the PE-surface allowed the application of a PEDOT electrode that exhibited good adherence. Screen printing of a designed pattern of poly 1,4(2-methoxy-5-(2-ethylhexyloxy))phenylenevinylene (MEH-PPV) from chlorobenzene...

Association between colonic polyps and diverticular disease

Institute of Scientific and Technical Information of China (English)

Tetsuo Hirata; Yuko Kawakami; Nagisa Kinjo; Susumu Arakald; Tetsu Arakaki; Akira Hokama; Fukunori Kinjo; Jim Fujita

2008-01-01

AIM: TO evaluate the association between colonic polyps and diverticular disease in Japan.METHODS: We retrospectively reviewed the medical records of 672 consecutive patients who underwent total colonoscopy between August 2006 and April 2007 at Nishinjo Hospital, Okinawa, Japan. Patients with ahistory of any of the following were excluded from the study: previous polypectomy, colonic resection, and inflammatory bowel diseases. The association between colonic polyps and diverticular disease was analyzed by logistic regression analysis, adjusted for age and sex.RESULTS: Prevalence of colonic polyps in all patients with diverticular disease was significantly higher than that in those without diverticular disease (adjusted odds ratio 1.7).CONCLUSION: Our data showed that patients with diverticular disease have a higher risk of colonic polyps compared to those without.

Recurrent giant fibrovascular polyp of the esophagus

OpenAIRE

Lee, Ser Yee; Chan, Weng Hoong; Sivanandan, Ranjiv; Lim, Dennis Teck Hock; Wong, Wai Keong

2009-01-01

Giant fibrovascular polyps of the esophagus and hypopharynx are rare benign esophageal tumors. They arise most commonly in the upper esophagus and may, rarely, originate in the hypopharynx. They can vary significantly in size. Even though they are benign, they may be lethal due to either bleeding or, rarely, asphyxiation if a large polyp is regurgitated. Patients commonly present with dysphagia or hematemesis. The polyps may not be well visualized on endoscopy and imaging plays a vital role i...

Conductive polymer/metal composites for interconnect of flexible devices

Science.gov (United States)

Kawakita, Jin; Hashimoto Shinoda, Yasuo; Shuto, Takanori; Chikyow, Toyohiro

2015-06-01

An interconnect of flexible and foldable devices based on advanced electronics requires high electrical conductivity, flexibility, adhesiveness on a plastic substrate, and efficient productivity. In this study, we investigated the applicability of a conductive polymer/metal composite to the interconnect of flexible devices. By combining an inkjet process and a photochemical reaction, micropatterns of a polypyrrole/silver composite were formed on flexible plastic substrates with an average linewidth of approximately 70 µm within 10 min. The conductivity of the composite was improved to 6.0 × 102 Ω-1·cm-1. From these results, it is expected that the conducting polymer/metal composite can be applied to the microwiring of flexible electronic devices.

Inorganic Metal Oxide/Organic Polymer Nanocomposites And Method Thereof

Science.gov (United States)

Gash, Alexander E.; Satcher, Joe H.; Simpson, Randy

2004-11-16

A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal in organic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophilic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N.sub.2 adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the material, providing superb mixing of the component phases in the energetic nanocomposite.

Plasma coatings of nitrogen polymers on metal prostheses of the circulatory system

International Nuclear Information System (INIS)

Gomez J, L. M.

2016-01-01

This work has a study about the synthesis of poly aniline, poly allylamine and poly pyrrole doped with iodine onto metallic surfaces similar to stents for the circulatory system. Ar, water and hydrogen peroxide plasmas were used for eroding, conditioning and synthesizing polymers that potentially reduce some rejection reactions when stents are implanted in the human body. Stents are small metallic meshes that applied inside collapsed arteries or veins enlarge the diameter and restore the blood flow, however the metallic surfaces usually cause rejection reactions that obstruct the veins again. To give solutions to this problem, in this work is studied the synthesis of biocompatible polymer coatings on the stents that resist the blood flow forming a biocompatible interface between metal and blood. The metallic substrates were eroded and chemically prepared with Ar, H_2O and/or H_2O_2 glow discharges on which the polymers were synthesized by plasma. The coatings were morphologically characterized by optical, scanning electron and atomic force microscopy, the chemical structure was studied by infrared and photoelectron X-ray spectroscopy. The hydrophilicity was studied measuring the advance static contact angle and the adhesion was evaluated indirectly with scanning electron microscopy after two months submerged in buffered phosphate solutions. The results indicate that the polymers grew following the superficial morphology; that the conditioning with Ar ions erode the substrates and that the conditioning with H_2O or H_2O_2 erodes and activates the surface generating oxygen bridges which help in the polymer-metal adhesion. The chemical structure of the polymeric coatings contain crosslinked structures that correspond to links between monomers with the participation of all atoms, states that suggest monomer fragmentation and oxidation and states that indicate oxygen bridges in the polymers. The coatings had contact angles close to 90 degrees where is located the line

Hamartomatous polyps - a clinical and molecular genetic study

DEFF Research Database (Denmark)

Jelsig, Anne Marie

2016-01-01

the knowledge on clinical course and molecular genetics in patients with HPs and HPS, and to investigate research participants' attitude towards the results of extensive genetic testing. Paper I: In the first paper we investigated the occurrence, anatomic distribution, and other demographics of juvenile polyps...... appearance. Patients with one or a few juvenile polyps are usually not offered clinical follow-up as the polyp(s) are considered not to harbour any malignant potential. Nevertheless, it is important to note that juvenile polyps and HPs are also found in patients with hereditary hamartomatous polyposis......-Jeghers syndrome, and the PTEN hamartoma tumour syndrome. Currently, the HPS diagnoses are based on clinical criteria and are often assisted with genetic testing as candidate genes have been described for each syndrome. This thesis is based on six scientific papers. The overall aim of the studies was to expand...

Chemical metallization of KMPR photoresist polymer in aqueous solutions

Science.gov (United States)

Zeb, Gul; Duong, Xuan Truong; Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh; Salimy, Siamak; Le, Xuan Tuan

2017-06-01

While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

Molecular features of colorectal hyperplastic polyps and sessile serrated adenoma/polyps from Korea.

Science.gov (United States)

Kim, Kyoung-Mee; Lee, Eui Jin; Ha, Sangyun; Kang, So Young; Jang, Kee-Taek; Park, Cheol Keun; Kim, Jin Yong; Kim, Young Ho; Chang, Dong Kyung; Odze, Robert Daniel

2011-09-01

Abundant recent data suggest that sessile serrated adenoma/polyp (SSA/P) is an early precursor lesion in the serrated pathway of carcinogenesis. It is believed that SSA/Ps develop cancer by an SSA/P-dysplasia-carcinoma sequence. Hyperplastic polyps (HPs) share some histologic and molecular characteristics with SSA/P, but it is unclear whether SSA/Ps are derived from HPs or whether they develop by a different pathogenetic pathway. Previous studies have shown that serrated polyps from Korean patients show different prevalence rates of certain molecular abnormalities compared with similar lesions from American patients, and this suggests that lifestyle and dietary factors may influence the serrated neoplasia pathway. The purpose of this study was to evaluate the molecular features of HPs and SSA/Ps, the latter both with and without dysplasia, from Korean patients and to compare the findings with similar lesions from American patients. One hundred and eleven serrated polyps, consisting of 45 HPs (30 microvesicular, 11 goblet cell, 4 mucin depleted) and 56 SSA/Ps (36 with dysplasia, 20 without dysplasia), were retrieved from the pathology files of a large medical center in Korea and 38 SSA/P from American patients were evaluated for BRAF and KRAS mutations, microsatellite instability, and hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT), hMLH1, adenomatous polyposis coli (APC), p16, methylated in tumor-1 (MINT-1), MINT2, and MINT31. Methylation of hMLH1 was performed using 2 different sets of primers. Twenty-three conventional adenomas from Korean patients were included as controls. The data were compared between polyp subtypes and between polyps in the right versus the left colon. With regard to HP, KRAS mutations were present in 31.1% of polyps and BRAF mutations in 46.7% of polyps. KRAS mutations were significantly more common in goblet cell HP and BRAF in microvesicular HP (MVHP). Methylation of MGMT, hMLH1, APC, p16, MINT1, MINT2, and MINT31 were

Giant fibroepithelial polyp of the vulva

Directory of Open Access Journals (Sweden)

Selma Korkmaz

2014-12-01

Full Text Available Fibroepithelial polyps are among common benign skin lesions. They are usually small and skin-colored lesions and are located frequently in the axilla and neck. They are rarely seen in the vulva. There is a small number of cases that reach the giant sizes in this area in the literature. A 20-year-old female patient presented with a pedunculated mass measuring 25 cm in diameter, localized to the right labium majus. The lesion was excised and the histopathological diagnosis was fibroepithelial polyp. We present this case because of it is the largest reported fibroepithelial polyp of the vulva in the literature.

Association between colonic polyps and diverticular disease

Science.gov (United States)

Hirata, Tetsuo; Kawakami, Yuko; Kinjo, Nagisa; Arakaki, Susumu; Arakaki, Tetsu; Hokama, Akira; Kinjo, Fukunori; Fujita, Jiro

2008-01-01

AIM: To evaluate the association between colonic polyps and diverticular disease in Japan. METHODS: We retrospectively reviewed the medical records of 672 consecutive patients who underwent total colonoscopy between August 2006 and April 2007 at Nishinjo Hospital, Okinawa, Japan. Patients with a history of any of the following were excluded from the study: previous polypectomy, colonic resection, and inflammatory bowel diseases. The association between colonic polyps and diverticular disease was analyzed by logistic regression analysis, adjusted for age and sex. RESULTS: Prevalence of colonic polyps in all patients with diverticular disease was significantly higher than that in those without diverticular disease (adjusted odds ratio 1.7). CONCLUSION: Our data showed that patients with diverticular disease have a higher risk of colonic polyps compared to those without. PMID:18416471

Cyclooxygenase-2 overexpression is common in serrated and non-serrated colorectal adenoma, but uncommon in hyperplastic polyp and sessile serrated polyp/adenoma

Directory of Open Access Journals (Sweden)

Kirkner Gregory J

2008-01-01

Full Text Available Abstract Background Cyclooxygenase-2 (COX-2, PTGS2 plays an important role in colorectal carcinogenesis. COX-2 overexpression in colorectal cancer is inversely associated with microsatellite instability (MSI and the CpG island methylator phenotype (CIMP. Evidence suggests that MSI/CIMP+ colorectal cancer may arise through the serrated tumorigenic pathway through various forms of serrated neoplasias. Therefore, we hypothesized that COX-2 may play a less important role in the serrated pathway. Methods By immunohistochemistry, we assessed COX-2 expression in 24 hyperplastic polyps, 7 sessile serrated polyp/adenomas (SSA, 5 mixed polyps with SSA and adenoma, 27 traditional serrated adenomas, 515 non-serrated adenomas (tubular adenoma, tubulovillous adenoma and villous adenoma, 33 adenomas with intramucosal carcinomas, 96 adenocarcinomas with serration (corkscrew gland and 111 adenocarcinomas without serration. Results Strong (2+ COX-2 overexpression was more common in non-serrated adenomas (28% = 143/515 than in hyperplastic polyps (4.2% = 1/24, p = 0.008 and serrated polyps (7 SSAs and 5 mixed polyps (0% = 0/12, p = 0.04. Furthermore, any (1+/2+ COX-2 overexpression was more frequent in non-serrated adenomas (60% = 307/515 than in hyperplastic polyps (13% = 3/24, p Conclusion COX-2 overexpression is infrequent in hyperplastic polyp, SSA and mixed polyp with SSA and adenoma, compared to non-serrated and serrated adenoma. COX-2 overexpression becomes more frequent as tumors progress to higher grade neoplasias. Our observations suggest that COX-2 may play a less significant role in the serrated pathway of tumorigenesis; however, COX-2 may still play a role in later stage of the serrated pathway.

Synthesis and characterization of metal ion-imprinted polymers

Indian Academy of Sciences (India)

2018-03-29

Mar 29, 2018 ... polymers (CPs) were synthesized through the same method without using metal ion. Characterization of the ... tizanidine obtained from MMIP-NPs showed that signifi- .... C=C vari- able alkene stretching band at 1636 cm. −1.

Prevalence and risk factors of the gallbladder polyps diagnosed by ultrasound

International Nuclear Information System (INIS)

Lee, Mi Hwa; Cho, Pyong Kon; Kwon, Duck Moon

2015-01-01

This study was designed to determine the prevalence of gallstones in the last three years and evaluate the associated risk factors in the population who underwent health screening. Although there are many studies reporting the prevalence and risk factors of GB polyp, the results varied among each report. The aims of this study were to evaluate the prevalence rate and risk factors of GB polyp, colon polyp and fatty liver in the population who underwent health screening. The study population consisted of 4,877 visited the health promotion center in Dalseogu, Daegu in Korea from January 2011 to December 2013. Each participant in the study had their biliary system gallbladder examined using ultrasonography. The prevalence of GB polyp was evaluated along with age, gender, metabolic syndrom, body mass index (BMI), Fatty liver, Colon polyp. A showed of total 383 (7.9%) people were found to have GB polyps. The prevalence of sex among 256 (9.8%) patients men and 127 (5.6%) women which showed significantly higher in male than in female subjects(p=0.001). The mean size of the GB polyps 4.92 mm (1.6-17 mm). The sizes of most GB polyps (73.6%) were less than 10 mm in diameter. 122 subjects (31.28%) had multiple GB polyps which 2 or more polyps and 261 subjects (68.2%) had single polyp. Independent risk factors related with GB polyp were male gender (OR 0.551, p<0.001), overweight that BMI above 23 kg/m"2 (OR 0.713, p=0.002) triglyceride (OR 0.571, p<0.001), metabolic syndrome (OR 0.049, p=0.033) and colon polyp (OR 1.409, p=0.002). In spite of the conclusion, the prevalence GB polyp was higher than previous Korea and other country reports. The GB polyp in a healthy population was results as 7.9%. The risk factors of GB polyps were found to be male, being overweight, triglyceride, metabolic syndrome and colon polyp. Not only the subject of a health examination is needed but, a further study of the general public when possible

Prevalence and risk factors of the gallbladder polyps diagnosed by ultrasound

Energy Technology Data Exchange (ETDEWEB)

Lee, Mi Hwa; Cho, Pyong Kon [Dept. of Radiological science, Catholic University of Daegu, Daegu (Korea, Republic of); Kwon, Duck Moon [Dept. of Diagnostic Radiology, Daegu Health College, Daegu (Korea, Republic of)

2015-06-15

This study was designed to determine the prevalence of gallstones in the last three years and evaluate the associated risk factors in the population who underwent health screening. Although there are many studies reporting the prevalence and risk factors of GB polyp, the results varied among each report. The aims of this study were to evaluate the prevalence rate and risk factors of GB polyp, colon polyp and fatty liver in the population who underwent health screening. The study population consisted of 4,877 visited the health promotion center in Dalseogu, Daegu in Korea from January 2011 to December 2013. Each participant in the study had their biliary system gallbladder examined using ultrasonography. The prevalence of GB polyp was evaluated along with age, gender, metabolic syndrom, body mass index (BMI), Fatty liver, Colon polyp. A showed of total 383 (7.9%) people were found to have GB polyps. The prevalence of sex among 256 (9.8%) patients men and 127 (5.6%) women which showed significantly higher in male than in female subjects(p=0.001). The mean size of the GB polyps 4.92 mm (1.6-17 mm). The sizes of most GB polyps (73.6%) were less than 10 mm in diameter. 122 subjects (31.28%) had multiple GB polyps which 2 or more polyps and 261 subjects (68.2%) had single polyp. Independent risk factors related with GB polyp were male gender (OR 0.551, p<0.001), overweight that BMI above 23 kg/m{sup 2} (OR 0.713, p=0.002) triglyceride (OR 0.571, p<0.001), metabolic syndrome (OR 0.049, p=0.033) and colon polyp (OR 1.409, p=0.002). In spite of the conclusion, the prevalence GB polyp was higher than previous Korea and other country reports. The GB polyp in a healthy population was results as 7.9%. The risk factors of GB polyps were found to be male, being overweight, triglyceride, metabolic syndrome and colon polyp. Not only the subject of a health examination is needed but, a further study of the general public when possible.

Evaluating success of curettage in the surgical treatment of endometrial polyps.

Science.gov (United States)

Hafizi, Leili; Mousavifar, Nezhat; Zirak, Nahid; Khadem, Nayereh; Davarpanah, Sousan; Akhondi, Mohsen

2015-02-01

To determine treatment efficacy of curettage on endometrial polyp. The quasi-experimental pre-and-post study was conducted in 2011-12 at the gynaecology department of Imam Reza Hospital, Mashhad, Iran, and comprised patients who underwent hysteroscopy for endometrial polyp. Location, size, number and base condition of the polyps were recorded before the patient underwent curettage. Hysteroscopy was then performed and the condition of the remaining polyps was compared with initial findings. Also, the remaining polyps were resected. SPSS 13 was used for statistical analysis. There were 51 patients in the study with a mean age of 33.14 ± 8.19 years (range: 23-59 years)Besides, there were 82 polyps; 38(46.3%) having a narrow base, and 44(53.7%) having a wide base. The mean polyp size was 2.39 ± 2.63cm.After performing curettage, 23 (28.0%) polyps were removed completely, 39(47.6%) had size reduction, and 20(24.4%) had no change in size. Curettage could not significantly remove polyps (p < 0.001). Polyps smaller than 2cm were more likely to have been removed compared to the bigger ones (p = 0.003).Polyps with wide base were more significantly removed than those with narrow base (p < 0.001).Further, those with wide base and also smaller than 2 cm were removed more significantly than others (p < 0.001).The location of polyps had no effect on removal probability by curettage (p = 0.114). Curettage was not found to be a reliable method for endometrial polyp removal. If hysteroscopy is not accessible, the size of the polyp should be determined by vaginal sonograghy to estimate the probability of its removal by curettage.

Electrochemistry of conductive polymers 39. Contacts between conducting polymers and noble metal nanoparticles studied by current-sensing atomic force microscopy.

Science.gov (United States)

Cho, Shin Hyo; Park, Su-Moon

2006-12-28

Electrical properties of contacts formed between conducting polymers and noble metal nanoparticles have been examined using current-sensing atomic force microscopy (CS-AFM). Contacts formed between electrochemically prepared pi-conjugated polymer films such as polypyrrole (PPy), poly(3-methylthiophene) (P3MeT), as well as poly(3,4-ethylenedioxythiophene) (PEDOT) and noble metal nanoparticles including platinum (Pt), gold (Au), and silver (Ag) have been examined. The Pt nanoparticles were electrochemically deposited on a pre-coated PPy film surface by reducing a platinum precursor (PtCl62-) at a constant potential. Both current and scanning electron microscopic images of the film showed the presence of Pt islands. The Au and Ag nanoparticles were dispersed on the P3MeT and PEDOT film surfaces simply by dipping the polymer films into colloid solutions containing Au or Ag particles for specified periods (5 to approximately 10 min). The deposition of Au or Ag particles resulted from either their physical adsorption or chemical bonding between particles and the polymer surface depending on the polymer. When compared with PPy, P3MeT and PEDOT showed a stronger binding to Au or Ag nanoparticles when dipped in their colloidal solutions for the same period. This indicates that Au and Ag particles are predominantly linked with the sulfur atoms via chemical bonding. Of the two, PEDOT was more conductive at the sites where the particles are connected to the polymer. It appears that PEDOT has better aligned sulfur atoms on the surface and is strongly bonded to Au and Ag nanoparticles due to their strong affinity to gold and silver. The current-voltage curves obtained at the metal islands demonstrate that the contacts between these metal islands and polymers are ohmic.

The Marine Sponge-Derived Inorganic Polymers, Biosilica and Polyphosphate, as Morphogenetically Active Matrices/Scaffolds for the Differentiation of Human Multipotent Stromal Cells: Potential Application in 3D Printing and Distraction Osteogenesis

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Xiaohong Wang

2014-02-01

Full Text Available The two marine inorganic polymers, biosilica (BS, enzymatically synthesized from ortho-silicate, and polyphosphate (polyP, a likewise enzymatically synthesized polymer consisting of 10 to >100 phosphate residues linked by high-energy phosphoanhydride bonds, have previously been shown to display a morphogenetic effect on osteoblasts. In the present study, the effect of these polymers on the differential differentiation of human multipotent stromal cells (hMSC, mesenchymal stem cells, that had been encapsulated into beads of the biocompatible plant polymer alginate, was studied. The differentiation of the hMSCs in the alginate beads was directed either to the osteogenic cell lineage by exposure to an osteogenic medium (mineralization activation cocktail; differentiation into osteoblasts or to the chondrogenic cell lineage by incubating in chondrocyte differentiation medium (triggering chondrocyte maturation. Both biosilica and polyP, applied as Ca2+ salts, were found to induce an increased mineralization in osteogenic cells; these inorganic polymers display also morphogenetic potential. The effects were substantiated by gene expression studies, which revealed that biosilica and polyP strongly and significantly increase the expression of bone morphogenetic protein 2 (BMP-2 and alkaline phosphatase (ALP in osteogenic cells, which was significantly more pronounced in osteogenic versus chondrogenic cells. A differential effect of the two polymers was seen on the expression of the two collagen types, I and II. While collagen Type I is highly expressed in osteogenic cells, but not in chondrogenic cells after exposure to biosilica or polyP, the upregulation of the steady-state level of collagen Type II transcripts in chondrogenic cells is comparably stronger than in osteogenic cells. It is concluded that the two polymers, biosilica and polyP, are morphogenetically active additives for the otherwise biologically inert alginate polymer. It is proposed that

The marine sponge-derived inorganic polymers, biosilica and polyphosphate, as morphogenetically active matrices/scaffolds for the differentiation of human multipotent stromal cells: potential application in 3D printing and distraction osteogenesis.

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Wang, Xiaohong; Schröder, Heinz C; Grebenjuk, Vladislav; Diehl-Seifert, Bärbel; Mailänder, Volker; Steffen, Renate; Schloßmacher, Ute; Müller, Werner E G

2014-02-21

The two marine inorganic polymers, biosilica (BS), enzymatically synthesized from ortho-silicate, and polyphosphate (polyP), a likewise enzymatically synthesized polymer consisting of 10 to >100 phosphate residues linked by high-energy phosphoanhydride bonds, have previously been shown to display a morphogenetic effect on osteoblasts. In the present study, the effect of these polymers on the differential differentiation of human multipotent stromal cells (hMSC), mesenchymal stem cells, that had been encapsulated into beads of the biocompatible plant polymer alginate, was studied. The differentiation of the hMSCs in the alginate beads was directed either to the osteogenic cell lineage by exposure to an osteogenic medium (mineralization activation cocktail; differentiation into osteoblasts) or to the chondrogenic cell lineage by incubating in chondrocyte differentiation medium (triggering chondrocyte maturation). Both biosilica and polyP, applied as Ca²⁺ salts, were found to induce an increased mineralization in osteogenic cells; these inorganic polymers display also morphogenetic potential. The effects were substantiated by gene expression studies, which revealed that biosilica and polyP strongly and significantly increase the expression of bone morphogenetic protein 2 (BMP-2) and alkaline phosphatase (ALP) in osteogenic cells, which was significantly more pronounced in osteogenic versus chondrogenic cells. A differential effect of the two polymers was seen on the expression of the two collagen types, I and II. While collagen Type I is highly expressed in osteogenic cells, but not in chondrogenic cells after exposure to biosilica or polyP, the upregulation of the steady-state level of collagen Type II transcripts in chondrogenic cells is comparably stronger than in osteogenic cells. It is concluded that the two polymers, biosilica and polyP, are morphogenetically active additives for the otherwise biologically inert alginate polymer. It is proposed that alginate

Three-Dimensional (3D) Printing of Polymer-Metal Hybrid Materials by Fused Deposition Modeling.

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Fafenrot, Susanna; Grimmelsmann, Nils; Wortmann, Martin; Ehrmann, Andrea

2017-10-19

Fused deposition modeling (FDM) is a three-dimensional (3D) printing technology that is usually performed with polymers that are molten in a printer nozzle and placed line by line on the printing bed or the previous layer, respectively. Nowadays, hybrid materials combining polymers with functional materials are also commercially available. Especially combinations of polymers with metal particles result in printed objects with interesting optical and mechanical properties. The mechanical properties of objects printed with two of these metal-polymer blends were compared to common poly (lactide acid) (PLA) printed objects. Tensile tests and bending tests show that hybrid materials mostly containing bronze have significantly reduced mechanical properties. Tensile strengths of the 3D-printed objects were unexpectedly nearly identical with those of the original filaments, indicating sufficient quality of the printing process. Our investigations show that while FDM printing allows for producing objects with mechanical properties similar to the original materials, metal-polymer blends cannot be used for the rapid manufacturing of objects necessitating mechanical strength.

Factors Influencing the Recurrence Potential of Benign Endometrial Polyps after Hysteroscopic Polypectomy.

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Jehn-Hsiahn Yang

Full Text Available An endometrial polyp is a frequently encountered gynecologic disease with abnormal uterine bleeding and infertility being the two common presenting problems, and hysteroscopic polypectomy is an effective method to remove them. The postoperative polyp recurrence might result in reappearance of abnormal uterine bleeding or infertility, whereas factors influencing the postoperative recurrence potential have limited data.This case-series report included 168 premenopausal women who suffered from endometrial polyps and underwent hysteroscopic polypectomy. All of them were awaiting a future pregnancy. Office hysteroscopy was done before and after hysteroscopic polypectomy, in which preoperative hysteroscopy examined the number, type, and location of endometrial polyps, and postoperative hysteroscopy checked the polyp recurrence. Surgical indications, either infertility or the presentation of abnormal uterine bleeding, and follow-up duration were recorded.Seventy-three out of 168 (43% women had polyp recurrence after hysteroscopic polypectomy. Multivariate logistic regression analysis revealed that more endometrial polyps (P = 0.015 and longer duration of follow-up (P = 0.004 were significantly associated with an increased risk of postoperative polyp recurrence. The type of endometrial polyps was not correlated with polyp recurrence potential, whereas pedunculated type endometrial polyps were closely related to the presentation of abnormal uterine bleeding (P = 0.001.A higher number of endometrial polyps and longer follow-up duration are associated with a greater potential of polyp recurrence after hysteroscopic polypectomy.

Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing.

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Chen, Chen; Tang, Yongan; Vlahovic, Branislav; Yan, Fei

2017-12-01

The integration of different noble metal nanostructures, which exhibit desirable plasmonic and/or electrocatalytic properties, with electrospun polymer nanofibers, which display unique mechanical and thermodynamic properties, yields novel hybrid nanoscale systems of synergistic properties and functions. This review summarizes recent advances on how to incorporate noble metal nanoparticles into electrospun polymer nanofibers and illustrates how such integration paves the way towards chemical sensing applications with improved sensitivity, stability, flexibility, compatibility, and selectivity. It is expected that further development of this field will eventually make a wide impact on many areas of research.

Metal{Polymer Hybrid Materials For Flexible Transparent Conductors

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Narayanan, Sudarshan

The field of organic electronics, till recently a mere research topic, is currently making rapid strides and tremendous progress into entering the mainstream electronics industry with several applications and products such as OLED televisions, curved displays, wearable devices, flexible solar cells, etc. already having been commercialized. A major component in these devices, especially for photovoltaic applications, is a transparent conductor used as one of the electrodes, which in most commercial applications are highly doped wide bandgap semiconducting oxides also called Transparent Conducting Oxides (TCOs). However, TCOs exhibit inherent disadvantages such as limited supply, brittle mechanical properties, expensive processing that present major barriers for the more widespread economic use in applications such as exible transparent conductors, owing to which suitable alternative materials are being sought. In this context we present two approaches in realizing alternative TCs using metal-polymer hybrid materials, with high figures of merit that are easily processable, reasonably inexpensive and mechanically robust as well. In this context, our first approach employs laminated metal-polymer photonic bandgap structures to effectively tune optical and electrical properties by an appropriate design of the material stack, factoring in the effect of the materials involved, the number of layers and layer properties. We have found that in the case of a four-bilayer Au/polystyrene (AujPS) laminate structure, an enhancement in optical transmittance of ˜ 500% in comparison to a monolithic A film of equivalent thickness, can be achieved. The high conductivity (˜ 106 O--1cm--1) of the metallic component, Au in this case, also ensures planar conductivity; metallic inclusions in the dielectric polymer layer can in principle give rise to out-of-plane conductivity as well enabling a fully functional TC. Such materials also have immense potential for several other applications

Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes

International Nuclear Information System (INIS)

Ogihara, Wataru; Sun Jiazeng; Forsyth, Maria; MacFarlane, Douglas R.; Yoshizawa, Masahiro; Ohno, Hiroyuki

2004-01-01

We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10 -4 to 10 -3 S cm -1 at room temperature. Gelation was found to cause little change in the 7 Li diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids

Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

International Nuclear Information System (INIS)

Fish, D.

1996-01-01

The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished

Endometrial Intraepithelial Neoplasia (EIN In An Endometrial Polyp

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Devic Ana

2015-12-01

Full Text Available Endometrial intraepithelial neoplasia (EIN is a monoclonal neoplastic cell proliferation of the endometrium associated with a significantly increased risk of endometrioid endometrial adenocarcinoma. We herein present the case of a 58-year-old female patient who underwent a hysterectomy with bilateral salpingo-oophorectomy because of the existence of endometrial intraepithelial neoplasia in an endometrial polyp. The patient had irregular uterine bleeding, which lasted 10 days. An endometrial polyp was diagnosed by ultrasound examination. The polyp was located in the isthmus of the uterus, on the back wall, and measured 32 mm × 25 mm. The patient underwent fractional dilation and curettage, and the specimens were subjected to a histopathological examination. The histopathological findings were EIN, endometrioid type, a focus of which was found within the endometrial polyps, as well as the endometrial polyp and proliferative endometrium. The endocervical tissue was normal. Given the age of the patient and the histopathological findings, she underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy. The final histopathological findings were EIN, endometrioid type with a focus found within the endometrial polyp; endometrial polyp; simple hyperplasia; chronic inflammation of the uterine cervix; hyperkeratosis of the cervical squamous epithelium; and cervicitis chronica. There was also hydrosalpinx of the left fallopian tube, and cystic follicles in the left ovary. There was no significant morphological change in the right ovary or fallopian tube. The surgical and postoperative course were normal. The patient was sent home on the fifth postoperative day in good general condition. A check-up performed one month after surgery showed normal findings.

Prolapsing Gastric Polyp Causing Intermittent Gastric Outlet Obstruction.

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Kosai, Nik Ritza; Gendeh, Hardip Singh; Norfaezan, Abdul Rashid; Razman, Jamin; Sutton, Paul Anthony; Das, Srijit

2015-06-01

Gastric polyps are often an incidental finding on upper gastrointestinal endoscopy, with an incidence up to 5%. The majority of gastric polyps are asymptomatic, occurring secondary to inflammation. Prior reviews discussed Helicobacter pylori (H pylori)-associated singular gastric polyposis; however, we present a rare and unusual case of recurrent multiple benign gastric polyposis post H pylori eradication resulting in intermittent gastric outlet obstruction. A 70-year-old independent male, Chinese in ethnicity, with a background of diabetes mellitus, hypertension, and a simple renal cyst presented with a combination of melena, anemia, and intermittent vomiting of partially digested food after meals. Initial gastroscopy was positive for H pylori; thus he was treated with H pylori eradication and proton pump inhibitors. Serial gastroscopy demonstrated multiple sessile gastric antral polyps, the largest measuring 4 cm. Histopathologic examination confirmed a benign hyperplastic lesion. Computed tomography identified a pyloric mass with absent surrounding infiltration or metastasis. A distal gastrectomy was performed, whereby multiple small pyloric polyps were found, the largest prolapsing into the pyloric opening, thus explaining the intermittent nature of gastric outlet obstruction. Such polyps often develop from gastric ulcers and, if left untreated, may undergo neoplasia to form malignant cells. A distal gastrectomy was an effective choice of treatment, taking into account the polyp size, quantity, and potential for malignancy as opposed to an endoscopic approach, which may not guarantee a complete removal of safer margins and depth. Therefore, surgical excision is favorable for multiple large gastric polyps with risk of malignancy.

Natural history of diminutive colorectal polyps: long-term prospective observation by colonoscopy.

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Mizuno, Ken-Ichi; Suzuki, Yutaka; Takeuchi, Manabu; Kobayashi, Masaaki; Aoyagi, Yutaka

2014-04-01

Endoscopic removal of colorectal adenomatous polyps effectively prevents cancer. However, the treatment strategy for diminutive polyps (diameter ≤ 5 mm) remains controversial. Understanding the natural history of diminutive polyps is a prerequisite to their effective management. We prospectively examined the natural history of diminutive polyps by long-term surveillance colonoscopy. A total of 207 polyps detected in 112 patients from December 1991 through March 2002 were studied. To avoid potential effects on size and morphological characteristics, all polyps were selected randomly and were followed without biopsy. Polyp size was estimated by comparing the lesion with the diameter of a biopsy forceps. Mean follow up was 7.8 years (SD, 4.8; range, 1.0-18.6; median, 7.5; interquartile range 3.4-11.2). Twenty-four polyps were resected endoscopically, and the histopathological diagnosis was mucosal high-grade neoplasia (Category 4) for one polyp, and mucosal low-grade neoplasia (Category 3) for 23 polyps. Mean linear size of the polyps was 3.2 mm (SD, 1.0; range, 1.3-5.0) at initial colonoscopy and 3.8 mm (SD 1.6; range 1.3-10.0) at final colonoscopy (Ppit pattern was associated with a lower growth rate than a type IIIL1 pattern. We clarified the natural history of diminutive polyps by long-term follow-up colonoscopy. The benign course of diminutive polyps should be considered in the design of treatment strategies. © 2014 The Authors. Digestive Endoscopy © 2014 Japan Gastroenterological Endoscopy Society.

Diagnostic Performance of CT Colonography for the Detection of Colorectal Polyps

International Nuclear Information System (INIS)

Yun, Ji Young; Ro, Hee Jeong; Choi, Jung Bin; Chung, Ji Eun; Kim, Yong Jin; Suh, Won Hyuck; Lee, Jong Kyun; Park, Jong Beom

2007-01-01

To investigate the diagnostic value of CT colonography for the detection of colorectal polyps. From December 2004 to December 2005, 399 patients underwent CT colonography and follow-up conventional colonoscopy. We excluded cases of advanced colorectal cancer. We retrospectively analyzed the CT colonography findings and follow-up conventional colonoscopy findings of 113 patients who had polyps more than 6 mm in diameter. Radiologists using 3D and 2D computer generated displays interpreted the CT colonography images. The colonoscopists were aware of the CT colonography findings before the procedure. CT colonography detected 132 polyps in 107 of the 113 patients and conventional colonoscopy detected 114 colorectal polyps more than 6 mm in diameter in 87 of the 113 patients. The sensitivity of CT colonography analyzed per polyp was 91% (41/45) for polyps more than 10 mm in diameter and 89% (101/114) for polyps more than 6 mm in diameter. Thirteen polyps were missed by CT colonography and were detected on follow-up conventional colonoscopy. CT colonography is a sensitive diagnostic tool for the detection of colorectal polyps and adequate bowel preparation, optimal bowel distention and clinical experience are needed to reduce the rate of missing appropriate lesions

The use of polymer gel dosimetry to measure dose distribution around metallic implants

International Nuclear Information System (INIS)

Nagahata, Tomomasa; Yamaguchi, Hajime; Monzen, Hajime; Nishimura, Yasumasa

2014-01-01

A semi-solid polymer dosimetry system using agar was developed to measure the dose distribution close to metallic implants. Dosimetry of heterogeneous fields where electron density markedly varies is often problematic. This prompted us to develop a polymer gel dosimetry technique using agar to measure the dose distribution near substance boundaries. Varying the concentration of an oxygen scavenger (tetra-hydroxymethyl phosphonium chloride) showed the absorbed dose and transverse relaxation rate of the magnetic resonance signal to be linear between 3 and 12 Gy. Although a change in the dosimeter due to oxidization was observed in room air after 24 hours, no such effects were observed in the first 4 hours. The dose distribution around the metal implants was measured using agar dosimetry. The metals tested were a lead rod, a titanium hip joint, and a metallic stent. A maximum 30% dose increase was observed near the lead rod, but only a 3% increase in the absorbed dose was noted near the surface of the titanium hip joint and metallic stent. Semi-solid polymer dosimetry using agar thus appears to be a useful method for dosimetry around metallic substances. (author)

[The use of polymer gel dosimetry to measure dose distribution around metallic implants].

Science.gov (United States)

Nagahata, Tomomasa; Yamaguchi, Hajime; Monzen, Hajime; Nishimura, Yasumasa

2014-10-01

A semi-solid polymer dosimetry system using agar was developed to measure the dose distribution close to metallic implants. Dosimetry of heterogeneous fields where electron density markedly varies is often problematic. This prompted us to develop a polymer gel dosimetry technique using agar to measure the dose distribution near substance boundaries. Varying the concentration of an oxygen scavenger (tetra-hydroxymethyl phosphonium chloride) showed the absorbed dose and transverse relaxation rate of the magnetic resonance signal to be linear between 3 and 12 Gy. Although a change in the dosimeter due to oxidization was observed in room air after 24 hours, no such effects were observed in the first 4 hours. The dose distribution around the metal implants was measured using agar dosimetry. The metals tested were a lead rod, a titanium hip joint, and a metallic stent. A maximum 30% dose increase was observed near the lead rod, but only a 3% increase in the absorbed dose was noted near the surface of the titanium hip joint and metallic stent. Semi-solid polymer dosimetry using agar thus appears to be a useful method for dosimetry around metallic substances.

Antral hyperplastic polyp: A rare cause of gastric outlet obstruction.

Science.gov (United States)

Aydin, Ibrahim; Ozer, Ender; Rakici, Halil; Sehitoglu, Ibrahim; Yucel, Ahmet Fikret; Pergel, Ahmet; Sahin, Dursun Ali

2014-01-01

Gastric polyps are usually found incidentally during upper gastrointestinal endoscopic examinations. These polyps are generally benign, with hyperplasia being the most common. While gastric polyps are often asymptomatic, they can cause gastric outlet obstruction. A 64 years-old female patient presented to our polyclinic with a history of approximately 2 months of weakness, occasional early nausea, vomiting after meals and epigastric pain. A polypoid lesion of approximately 25mm in diameter was detected in the antral area of the stomach, which prolapsed through the pylorus into the duodenal bulbus, and subsequently caused gastric outlet obstruction, as revealed by upper gastrointestinal endoscopy of the patient. The polyp was retrieved from the pyloric canal into the stomach with the aid of a tripod, and snare polypectomy was performed. Currently, widespread use of endoscopy has led to an increase in the frequency of detecting hyperplastic polyps. While most gastric polyps are asymptomatic, they can cause iron deficiency anemia, acute pancreatitis and more commonly, gastric outlet obstruction because of their antral location. Although there are no precise principles in the treatment of asymptomatic polyps, polyps >5mm should be removed due to the possibility of malignant transformation. According to the medical evidence, polypectomy is required for gastric hyperplastic polyps because of the risks of complication and malignancy. These cases can be successfully treated endoscopically. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Relation between obesity and adenomatous polyps of the large bowel.

Science.gov (United States)

Sato, Yumi; Nozaki, Ryoichi; Yamada, Kazutaka; Takano, Masahiro; Haruma, Ken

2009-07-01

We compared the prevalence of colorectal adenoma (polyps) in men and women and examined the role of body mass index (BMI) on polyp risk according to patient age and gender. The risk of developing colorectal polyps was studied in 15 380 subjects (7155 men and 8225 women) who underwent colonoscopy for the first time from April 1998 to March 2006 at our 'Human Dry Dock', which is the check-up service provided in Japan. Eligible subjects were 20-86 years old (mean age +/- SD, 47.3 +/- 8.5) and were free of invasive cancer, hyperplastic polyps and familial polyposis. Polyps were found in 1590 subjects (1062 men and 528 women). The odds ratio (OR) of detection of polyps in relation to obesity was determined in all cases by multivariate logistic regression analysis after making an adjustment for gender and age. The OR of polyp detection in obese subjects (BMI >or= 25) versus non-obese subjects (BMI women. As the BMI increased in increments of one, the OR in men increased significantly to 1.01 (P women was unchanged at 1.00 (P = 0.23), which was without significance. We conclude that obesity in men is a risk factor for the development of polyps. These results must be confirmed by additional epidemiological studies.

Metal removal from aqueous media by polymer-assisted ultrafiltration with chitosan

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Grégorio Crini

2017-05-01

Full Text Available Polymer assisted ultrafiltration (PAUF is a relatively new process in water and wastewater treatment and the subject of an increasing number of papers in the field of membrane science. Among the commercial polymers used, poly(ethyleneimine and poly(acrylic acid are the most popular to complex numerous metal ions. Recently, there is an increasing interest in the use of chitosan, a natural linear polymer, as chelating agent for complexing metals. Chitosan has a high potential in wastewater treatment mainly due to its polyelectrolyte properties at acidic pH. The objectives of this review are to present the PAUF process and to highlight the advantages gained from the use of chitosan in the process of complexation–ultrafiltration. For this, a PAUF-based literature survey has been compiled and is discussed. From these data, chitosan, a biopolymer that is non-toxic to humans and the environment, is found to be effective in removing metal ions and exhibits high selectivity. It might be a promising polyelectrolyte for PAUF purposes.

Copper tolerance mediated by polyphosphate degradation and low-affinity inorganic phosphate transport system in Escherichia coli.

Science.gov (United States)

Grillo-Puertas, Mariana; Schurig-Briccio, Lici Ariane; Rodríguez-Montelongo, Luisa; Rintoul, María Regina; Rapisarda, Viviana Andrea

2014-03-19

Metal tolerance in bacteria has been related to polyP in a model in which heavy metals stimulate the polymer hydrolysis, forming metal-phosphate complexes that are exported. As previously described in our laboratory, Escherichia coli cells grown in media containing a phosphate concentration >37 mM maintained an unusually high polyphosphate (polyP) level in stationary phase. The aim of the present work was to evaluate the influence of polyP levels as the involvement of low-affinity inorganic phosphate transport (Pit) system in E. coli copper tolerance. PolyP levels were modulated by the media phosphate concentration and/or using mutants in polyP metabolism. Stationary phase wild-type cells grown in high phosphate medium were significantly more tolerant to copper than those grown in sufficient phosphate medium. Copper addition to tolerant cells induced polyP degradation by PPX (an exopolyphosphatase), phosphate efflux and membrane polarization. ppk-ppx- (unable to synthesize/degrade polyP), ppx- (unable to degrade polyP) and Pit system mutants were highly sensitive to metal even in high phosphate media. In exponential phase, CopA and polyP-Pit system would act simultaneously to detoxify the metal or one could be sufficient to safeguard the absence of the other. Our results support a mechanism for copper detoxification in exponential and stationary phases of E. coli, involving Pit system and degradation of polyP. Data reflect the importance of the environmental phosphate concentration in the regulation of the microbial physiological state.

New method for preparing a liquid crystal polymer that exhibits linearly polarized white fluorescence

International Nuclear Information System (INIS)

Zheng Shijun; Kun, Wang; Kobayashi, Takaomi

2011-01-01

With the aim of developing a single-chain white-light-emitting polymer, liquid crystal (LC) polymers with a shish-kebab-type moiety on their cross-conjugated (p-phenylene)s-poly(p-phenylenevinylene)s main chain were synthesized by Gilch polymerization. They were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarizing optical microscopy (POM). 1 H-NMR indicated that the polymers had a shish-kebab structure, which strongly suppressed the formation of structural defects in the polymers. DSC revealed that the polymers had thermotropic LC properties, indicating that the LC polymers were enantiotropic. XRD showed that the polymers had a mesophase, which implies that they were in a smectic LC phase. A polymer with 'kebabs' of 2,5-bis(4'-alkoxyphenyl)benzene was combined with an aligned polyimide film with orientated microgrooves. The polymer main chain was aligned due to the orientation of the 'kebabs' of the uniform cross-conjugated structure. It lay between the kebabs and the 'shish' of the polymer main chains. The aligned polymer main chain emitted yellow light while and the oriented LC side chains emitted blue light emission. These two emissions resulted in linearly polarized white fluorescence.

Salt-Driven Deposition of Thermoresponsive Polymer-Coated Metal Nanoparticles on Solid Substrates.

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Zhang, Zhiyue; Maji, Samarendra; da Fonseca Antunes, André B; De Rycke, Riet; Hoogenboom, Richard; De Geest, Bruno G

2016-06-13

Here we report on a simple, generally applicable method for depositing metal nanoparticles on a wide variety of solid surfaces under all aqueous conditions. Noble-metal nanoparticles obtained by citrate reduction followed by coating with thermoresponsive polymers spontaneously form a monolayer-like structure on a wide variety of substrates in presence of sodium chloride whereas this phenomenon does not occur in salt-free medium. Interestingly, this phenomenon occurs below the cloud point temperature of the polymers and we hypothesize that salt ion-induced screening of electrostatic charges on the nanoparticle surface entropically favors hydrophobic association between the polymer-coated nanoparticles and a hydrophobic substrate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermoluminescence and photoluminescence analyses of MEH-PPV, MDMO-PPV and RU(bpy)3 gamma-irradiated polymer thin films

International Nuclear Information System (INIS)

Ortiz-Morales, A.; Ortiz-Lopez, J.; Cruz-Zaragoza, E.; Gómez-Aguilar, R.

2015-01-01

Effects of irradiation with 60 Co gamma photons on poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(3′,7′ dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) and tris(2,2′-bipyridyl)dichlororuthenium(II) hexahydrate (Ru(bpy) 3 ) thin films were analyzed regarding their thermoluminescence (TL) and photoluminescence (PL) properties. A linear TL dose response was obtained from the MEH-PPV and MDMO-PPV polymer films in dose ranges of approximately 0.170–4.08 kGy and 0.170–0.850 kGy, respectively, followed by a supralinear behavior. A dependence on the conjugation length of the polymer chains which was favored by heating of the film, was observed, and irradiation generated a blue-shift in MEH-PPV and Ru(bpy) 3 . Furthermore, the PL structure was not modified. The most likely effect involved in the TL emission was trapping. The high activation energy values of the traps in the TL may be attributed in part to the binding energy of the exciton. A deconvolution process was carried out to obtain the kinetic parameters from the TL glow curves and PL spectra. - Highlights: • Irradiation effects on MEH-PPV, MDMO-PPV and Ru(bpy) 3 were analyzed by TL and PL. • The dose response of PPV derivatives was linear at higher doses (0.170–4.08 kGy). • Activation energy, was larger than 2 eV, suggest a possible good stability of traps. • PL spectra for non-irradiated and gamma irradiated polymer are almost identical

Water-soluble metal-binding polymers with ultrafiltration: A technology for the removal, concentration, and recovery of metal ions from aqueous streams

International Nuclear Information System (INIS)

Smith, B.F.; Robison, T.W.; Jarvinen, G.D.

1997-01-01

The use of water-soluble metal-binding polymers coupled with ultrafiltration (UF) is a technology under development to selectively concentrate and recover valuable or regulated metal-ions from dilute process or waste waters. The polymers have a sufficiently large molecular size that they can be separated and concentrated using commercially available UF technology. The polymers can then be reused by changing the solution conditions to release the metal-ions, which are recovered in a concentrated form for recycle or disposal. Pilot-scale demonstrations have been completed for a variety of waste streams containing low concentrations of metal ions including electroplating wastes (zinc and nickel) and nuclear waste streams (plutonium and americium). Many other potential commercial applications exist including remediation of contaminated solids. An overview of both the pilot-scale demonstrated applications and small scale testing of this technology are presented

Water-soluble metal-binding polymers with ultrafiltration: A technology for the removal, concentration, and recovery of metal ions from aqueous streams

Energy Technology Data Exchange (ETDEWEB)

Smith, B.F.; Robison, T.W.; Jarvinen, G.D.

1997-12-31

The use of water-soluble metal-binding polymers coupled with ultrafiltration (UF) is a technology under development to selectively concentrate and recover valuable or regulated metal-ions from dilute process or waste waters. The polymers have a sufficiently large molecular size that they can be separated and concentrated using commercially available UF technology. The polymers can then be reused by changing the solution conditions to release the metal-ions, which are recovered in a concentrated form for recycle or disposal. Pilot-scale demonstrations have been completed for a variety of waste streams containing low concentrations of metal ions including electroplating wastes (zinc and nickel) and nuclear waste streams (plutonium and americium). Many other potential commercial applications exist including remediation of contaminated solids. An overview of both the pilot-scale demonstrated applications and small scale testing of this technology are presented.

Association between Obesity, Serum Lipids, and Colorectal Polyps in Old Chinese People

Directory of Open Access Journals (Sweden)

Wen Yang

2013-01-01

Full Text Available Background. Colorectal cancer mostly arises from the polyps of colon. The aim of our study was to examine the association of body mass index (BMI and serum lipids with the colorectal polyps in old Chinese people. Methods. The risk of developing colorectal polyps was studied in 244 subjects (212 men and 32 women, 74.63 ± 11.63 years old who underwent colonoscopy for the first time from January 2008 to July 2012 at the Navy General Hospital, Beijing, China. According to the results of colonoscopy, all the subjects were divided into 112 normal control, 38 right colorectal polyps, 53 left colorectal polyps, and 41 both right and left colorectal polyps groups. The total plasma cholesterol, plasma triglyceride, plasma creatinine concentration, blood urinary nitrogen, and fasting glucose were determined using a multichannel analyzer. Results. There were significant differences among normal control, right colorectal polyps, left colorectal polyps, and both right and left polyps groups, which were the BMI, total cholesterol, triglycerides, creatinine, and urinary nitrogen. In binary logistic regression analysis, there were two risk factors associated with the occurrence of colorectal polyps, which included BMI and systolic blood pressure. Conclusions. Colorectal polyps were significantly associated with increased BMI, total cholesterol, and triglycerides levels.

Understanding the origins of metal-organic framework/polymer compatibility.

Science.gov (United States)

Semino, R; Moreton, J C; Ramsahye, N A; Cohen, S M; Maurin, G

2018-01-14

The microscopic interfacial structures for a series of metal-organic framework/polymer composites consisting of the Zr-based UiO-66 coupled with different polymers are systematically explored by applying a computational methodology that integrates density functional theory calculations and force field-based molecular dynamics simulations. These predictions are correlated with experimental findings to unravel the structure-compatibility relationship of the MOF/polymer pairs. The relative contributions of the intermolecular MOF/polymer interactions and the flexibility/rigidity of the polymer with respect to the microscopic structure of the interface are rationalized, and their impact on the compatibility of the two components in the resulting composite is discussed. The most compatible pairs among those investigated involve more flexible polymers, i.e. polyvinylidene fluoride (PVDF) and polyethylene glycol (PEG). These polymers exhibit an enhanced contact surface, due to a better adaptation of their configuration to the MOF surface. In these cases, the irregularities at the MOF surface are filled by the polymer, and even some penetration of the terminal groups of the polymer into the pores of the MOF can be observed. As a result, the affinity between the MOF and the polymer is very high; however, the pores of the MOF may be sterically blocked due to the strong MOF/polymer interactions, as evidenced by UiO-66/PEG composites. In contrast, composites involving polymers that exhibit higher rigidity, such as the polymer of intrinsic microporosity-1 (PIM-1) or polystyrene (PS), present interfacial microvoids that contribute to a decrease in the contact surface between the two components, thus reducing the MOF/polymer affinity.

The patient with multiple intestinal polyps.

Science.gov (United States)

Schulmann, Karsten; Pox, Christian; Tannapfel, Andrea; Schmiegel, Wolff

2007-01-01

The management of patients with multiple intestinal polyps may be difficult and greatly depends on the correct classification. Polyposis syndromes account for less than 1% of newly diagnosed colorectal cancers. In addition the risk for extracolonic cancer is increased in most syndromes. Here we report the case of a difficult patient with severe gastric polyposis and we present a review of polyposis syndromes such as classical and attenuated familial adenomatous polyposis (FAP), MYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis as well as rare polyposis syndromes. The most practical approach for the diagnostic workup in patients with newly diagnosed gastrointestinal polyposis is based on the histological typing of polyps. In addition, a detailed family history regarding cancer, polyps and congenital abnormalities should be obtained from every polyposis patient. Patients with multiple adenomas are most likely to suffer from FAP, AFAP or MAP. Of these, younger age and higher polyp count are most likely a diagnosis of typical FAP. Older age and fewer polyps favour a diagnosis of AFAP or MAP. Germline testing of the APC gene is suggested, and if negative, MYH gene testing should be done. In patients with hamartomas, extraintestinal features should be evaluated and reference histology should be initiated. In addition panintestinal imaging should be performed with EGD, colonoscopy and small bowel imaging (PE, CE, and MR) enteroclysis. For diagnostic and therapeutic problems a familial colorectal cancer center should be consulted. Using this algorithm, correct classification and adequate treatment should be possible for every polyposis patient.

Intravenous contrast enhanced computed tomography colonoscopy in children with suspected colonic polyps

International Nuclear Information System (INIS)

Bhatia, Anmol; Saxena, Akshay K.; Kalra, Naveen; Sodhi, Kushaljit S.; Thapa, Babu R.; Rao, Katragadda L.N.; Khandelwal, Niranjan

2013-01-01

Objective: The purpose of this study was to evaluate the diagnostic performance of intravenous contrast enhanced computed tomographic colonoscopy (IVCTC) in the diagnosis of clinically suspected colorectal polyps in children, using conventional colonoscopy (CC) as the gold standard. Methods: This was a prospective study conducted between July 2008 and June 2010. 30 pediatric patients with history of rectal bleeding and clinically suspected to have colorectal polyps were enrolled. All of the patients underwent IVCTC followed by CC. 30 IVCTC and 31 CC were performed in 30 patients. The findings of IVCTC were compared with those of CC. Statistical analysis was performed to obtain diagnostic performance values of IVCTC on per polyp (sensitivity and positive predictive value) and per patient (sensitivity, specificity, positive predictive value and negative predictive value) basis. Results: By IVCTC, 63 polyps were detected in 28 patients of which 53 polyps were eligible for inclusion in the statistical analysis. 60 polyps were detected by CC in 28 patients of which 50 polyps were eligible for inclusion in the statistical analysis. The per polyp sensitivity and positive predictive values were 94% and 88.6% respectively. The per patient sensitivity, specificity, positive predictive value, and negative predictive values were 96.4, 50, 96.4, and 50% respectively. Twenty polyps, in 10 patients, were visualized only after intravenous contrast administration of which 5 polyps, in 5 patients, were likely to have been missed in the absence of the intravenous contrast injection as these polyps were submerged in fluid. Four patients would have had a false negative CTC examination if the intravenous contrast had not been injected; while in another patient, the number of polyps would have been underestimated. Conclusion: CTC is capable of serving as a safe and efficient non-invasive tool for evaluating children with clinically suspected colorectal polyps. Administration of

Three-Dimensional (3D Printing of Polymer-Metal Hybrid Materials by Fused Deposition Modeling

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Susanna Fafenrot

2017-10-01

Full Text Available Fused deposition modeling (FDM is a three-dimensional (3D printing technology that is usually performed with polymers that are molten in a printer nozzle and placed line by line on the printing bed or the previous layer, respectively. Nowadays, hybrid materials combining polymers with functional materials are also commercially available. Especially combinations of polymers with metal particles result in printed objects with interesting optical and mechanical properties. The mechanical properties of objects printed with two of these metal-polymer blends were compared to common poly (lactide acid (PLA printed objects. Tensile tests and bending tests show that hybrid materials mostly containing bronze have significantly reduced mechanical properties. Tensile strengths of the 3D-printed objects were unexpectedly nearly identical with those of the original filaments, indicating sufficient quality of the printing process. Our investigations show that while FDM printing allows for producing objects with mechanical properties similar to the original materials, metal-polymer blends cannot be used for the rapid manufacturing of objects necessitating mechanical strength.

Metal-polymer nanocomposites for functional applications

Energy Technology Data Exchange (ETDEWEB)

Faupel, Franz; Zaporojtchenko, Vladimir; Strunskus, Thomas [Christian-Albrechts-Universitaet zu Kiel (Germany). Institut fuer Materialwissenschaft - Materialverbunde; Elbahri, Mady [Christian-Albrechts-Universitaet zu Kiel (Germany). Institut fuer Materialwissenschaft - Nanochemistry and Engineering

2010-12-15

Nanocomposites combine favorable features of the constituents on the nanoscale to obtain new functionalities. The present paper is concerned with the preparation of polymer-based nanocomposites consisting of metal nanoparticles in a polymer matrix and the resulting functional properties. Emphasis is placed on vapor phase deposition which inter alia allows the incorporation of alloy clusters with well defined composition and tailored filling factor profiles. Examples discussed here include optical composites with tuned particle surface plasmon resonances for plasmonic applications, magnetic high frequency materials with cut-off frequencies well above 1 GHz, sensors that are based on the dramatic change in the electronic properties near the percolation threshold, and antibacterial coatings which benefit from the large effective surface of nanoparticles and the increased chemical potential which both strongly enhance ion release. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Polymer waveguide couplers based on metal nanoparticle–polymer nanocomposites

International Nuclear Information System (INIS)

Signoretto, M; Suárez, I; Chirvony, V S; Martínez-Pastor, J; Abargues, R; Rodríguez-Cantó, P J

2015-01-01

In this work Au nanoparticles (AuNPs) are incorporated into poly(methyl methacrylate) (PMMA) waveguides to develop optical couplers that are compatible with planar organic polymer photonics. A method for growing AuNPs (of 10 to 100 nm in size) inside the commercially available Novolak resist is proposed with the intention of tuning the plasmon resonance and the absorption/scattering efficiencies inside the patterned structures. The refractive index of the MNP–Novolak nanocomposite (MNPs: noble metal nanoparticles) is carefully analysed both experimentally and numerically in order to find the appropriate fabrication conditions (filling factor and growth time) to optimize the scattering cross section at a desired wavelength. Then the nanocomposite is patterned inside a PMMA waveguide to exploit its scattering properties to couple and guide a normal incident laser light beam along the polymer. In this way, light coupling is experimentally demonstrated in a broad wavelength range (404–780 nm). Due to the elliptical shape of the MNPs the nanocomposite demonstrates a birefringence, which enhances the coupling to the TE mode up to efficiencies of around 1%. (paper)

Diffuse benign gastric inflammatory hyperplastic polyps presenting ...

African Journals Online (AJOL)

Benign gastric inflammatory hyperplasic polyps are benign lesions that rarely occur in young age. We report a case of diffuse benign gastric inflammatory hyperplastic polyps in a 19 year old boy who presented with cough, nausea, and hematamesis. In the presented case symptoms such as nausea and vomiting are non ...

A high-spin and durable polyradical: poly(4-diphenylaminium-1,2-phenylenevinylene).

Science.gov (United States)

Murata, Hidenori; Takahashi, Masahiro; Namba, Kazuaki; Takahashi, Naoki; Nishide, Hiroyuki

2004-02-06

A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekulé- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-N,N-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyrene 5 were synthesized and polymerized with a palladium-phosphine catalyst to afford the head-to-tail-linked polyradical precursors (1). Oxidation of 1 with the nitrosonium ion solubilized with a crown ether gave the aminium polyradicals (1(+)()) which were durable (half-life > 1 month) at room temperature in air. A high-spin ground state with an average S = (4.5)/2 for 1a(+) was proved even at room temperature by magnetic susceptibility, magnetization, ESR, and NMR measurements.

Polyp Detection and Segmentation from Video Capsule Endoscopy: A Review

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V. B. Surya Prasath

2016-12-01

Full Text Available Video capsule endoscopy (VCE is used widely nowadays for visualizing the gastrointestinal (GI tract. Capsule endoscopy exams are prescribed usually as an additional monitoring mechanism and can help in identifying polyps, bleeding, etc. To analyze the large scale video data produced by VCE exams, automatic image processing, computer vision, and learning algorithms are required. Recently, automatic polyp detection algorithms have been proposed with various degrees of success. Though polyp detection in colonoscopy and other traditional endoscopy procedure based images is becoming a mature field, due to its unique imaging characteristics, detecting polyps automatically in VCE is a hard problem. We review different polyp detection approaches for VCE imagery and provide systematic analysis with challenges faced by standard image processing and computer vision methods.

Investigation of over-moulded hybrid metal/polymer devices

DEFF Research Database (Denmark)

Tosello, Guido; Hansen, Hans Nørgaard; Tang, Peter Torben

2006-01-01

principles, in-process manufacturing technologies, as well as testing methodologies have to be established in order to be able to develop such integrated devices. In this paper an investigation of the bonding between miniaturized metal insert and a polymer matrix is presented. A special demonstrator...... was designed and manufactured by over-moulding and hot-embossing. The bonding strength between the insert and the plastic part was tested by means of a tensile test. A variety of parameters was studied in order to investigate their influence on the bonding: different polymeric and metallic materials, insert...

Lymphangiomatous Polyp of Tonsil: A Case Report.

Science.gov (United States)

Sayar, Hamide; Sayar, Çağdaş; Adamhasan, Fulya; Uğuz, Aysun

2016-01-01

Lymphangiomatous polyps of the palatine tonsils are uncommon hamartomatous proliferations that could be clinically misdiagnosed as malignant neoplasms. These polyps consist of dilated lymphatic vessels located inside fibrous and/or adipose tissue. In this paper, a 27-year-old man who presented to the outpatient clinic with a complaint of dysphagia is presented. On physical examination, the patient had a smooth, polypoid mass extending from the posterior section of the right palatine tonsil into the oropharynx. The patient underwent right tonsillectomy. Histopathological examination of the specimen showed typical features of a lymphangiomatous polyp of the tonsil. The case is reported with the accompanying literature to avoid the possibility of misdiagnosing it as a malignant lesion clinically.

Gallbladder stones and gallbladder polyps associated with increased risk of colorectal adenoma in men.

Science.gov (United States)

Liu, Yen-Ling; Wu, Jin-Shang; Yang, Yi-Ching; Lu, Feng-Hwa; Lee, Chih-Ting; Lin, Wan-Ju; Chang, Chih-Jen

2018-04-01

Most cases of colorectal cancer develop via an adenoma to carcinoma sequence. Gallbladder polyps share some risk factors with colorectal polyps. Little is known about the relationship between gallbladder diseases and different status of colorectal polyps by gender. This study was to investigate the association of gallbladder stones and polyps with colorectal adenomas by gender in a Taiwanese population. A total of 7066 eligible subjects who underwent a total colonoscopy as a part of health check-up between January 2001 and August 2009 were recruited. Colonoscopic findings were classified into polyp-free, non-neoplastic polyps and colorectal adenomas. Gallbladder stones and gallbladder polyps were diagnosed based on ultrasonographic findings. There was a significant difference in the status of colon polyps between subjects with and without gallbladder polyps. However, the status of colon polyps was not significantly different between subjects with or without gallbladder stones. After adjusting obesity, fasting plasma glucose, and other variables, there was a positive relationship between gallbladder polyps and colorectal adenomas (odds ratio [OR]: 1.396, 95% confidence interval [CI]: 1.115-1.747) but not non-neoplastic polyps in all subjects. In men, gallbladder polyps (OR: 1.560, 95% CI: 1.204-2.019) and gallbladder stones (OR: 1.465, 95% CI 1.081-1.984) were positively associated with colorectal adenomas. In women, neither gallbladder polyps nor gallbladder stones were significantly related to colon polyps. Both gallbladder polyps and gallbladder stones were associated with an increased risk of colorectal adenomas in men but not in women. Gender difference was significant for the association between gallbladder lesions and colorectal polyps. © 2017 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

The Colonoscopist's Expertise Affects the Characteristics of Detected Polyps

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Da Kyoung Jung

2016-01-01

Full Text Available Background/Aims: The influence of the endoscopist on the polyp detection rate (PDR is underappreciated in clinical practice. Moreover, flat lesions or lesions of the proximal colon are more difficult to detect. Here, we evaluated the differences in the PDR and the characteristics of detected polyps according to the experience of the colonoscopist. Methods: We collected data on 2,549 patients who underwent screening colonoscopy performed by three fellows. The PDR was calculated according to the percentage of patients who had at least one polyp (method A and according to the percentage of detected lesions (method B. The primary outcome included the change in the PDR, and the secondary outcome included the change in the characteristics of the detected polyps with increasing experience of the colonoscopist. Results: No proportional correlation was found between the PDR and increasing experience in colonoscopy with method A; however, with method B, the PDR increased after 400 colonoscopies (p=0.0209. With method B, the detection rates of small polyps (<5 mm (p=0.0015 and polyps in proximal sites (p=0.0050 increased after 300 colonoscopies. Conclusions: Our study demonstrated that the quality of a colonoscopy, measured by using the PDR, may increase when performed by experienced fellows.

A novel fabrication method for surface integration of metal structures into polymers (SIMSIP)

Science.gov (United States)

Carrion-Gonzalez, Hector

Recently developed flexible electronics applications require that the thin metal films embedded on elastomer substrates also be flexible. These electronic systems are radically different in terms of performance and functionality than conventional silicon-based devices. A key question is whether the metal deposited on flexible films can survive large strains without rupture. Cumbersome macro-fabrication methods have been developed for functional and bendable electronics (e.g., interconnects) encapsulated between layers of polymer films. However, future electronic applications may require electronic flexible devices to be in intimate contact with curved surfaces (e.g., retinal implants) and to be robust enough to withstand large and repeated mechanical deformations. In this research, a novel technique for surface integration of metal structures into polymers (SIMSIP) was developed. Surface embedding, as opposed to placing metal on polymers, provides better adherence while leaving the surface accessible for contacts. This was accomplished by first fabricating the micro-scale metal patterns on a quartz or Teflon mother substrate, and then embedding them to a flexible polyimide thin film. The technique was successfully used to embed micro-metal structures of gold (Au), silver (Ag), and copper (Cu) into polyimide films without affecting the functional properties of the either the metals or the polymers. Experimental results confirm the successful surface-embedding of metal structures as narrow as 0.6 microm wide for different geometries commonly used in circuit design. Although similar approaches exist in literature, the proposed methodology provides a simpler and more reliable way of producing flexible circuits/electronics that is also suitable for high volume manufacturing. In order to demonstrate the flexibility of metal interconnects fabricated using the SIMSIP technique, multiple Au electrodes (5 microm and 2.5 microm wide) were tested using the X-theta bending

Automated polyp measurement based on colon structure decomposition for CT colonography

Science.gov (United States)

Wang, Huafeng; Li, Lihong C.; Han, Hao; Peng, Hao; Song, Bowen; Wei, Xinzhou; Liang, Zhengrong

2014-03-01

Accurate assessment of colorectal polyp size is of great significance for early diagnosis and management of colorectal cancers. Due to the complexity of colon structure, polyps with diverse geometric characteristics grow from different landform surfaces. In this paper, we present a new colon decomposition approach for polyp measurement. We first apply an efficient maximum a posteriori expectation-maximization (MAP-EM) partial volume segmentation algorithm to achieve an effective electronic cleansing on colon. The global colon structure is then decomposed into different kinds of morphological shapes, e.g. haustral folds or haustral wall. Meanwhile, the polyp location is identified by an automatic computer aided detection algorithm. By integrating the colon structure decomposition with the computer aided detection system, a patch volume of colon polyps is extracted. Thus, polyp size assessment can be achieved by finding abnormal protrusion on a relative uniform morphological surface from the decomposed colon landform. We evaluated our method via physical phantom and clinical datasets. Experiment results demonstrate the feasibility of our method in consistently quantifying the size of polyp volume and, therefore, facilitating characterizing for clinical management.

Diagnostics of transparent polymer coatings of metal items

Science.gov (United States)

Varepo, L. G.; Ermakova, I. N.; Nagornova, I. V.; Kondratov, A. P.

2017-08-01

The methods of visual and instrumental express diagnostics of safety critical defects and non-uniform thickness of transparent mono- and multilayer polyolefin surface coating of metal items are analyzed in the paper. The instrumental diagnostics method relates to colorimetric measuring based on effects, which appear in the polarized light for extrusion polymer coatings. A color coordinates dependence (in the color system CIE La*b*) on both HDPE / PVC coating thickness fluctuation values (from average ones) and coating interlayer or adhesion layer delaminating is shown. A variation of color characteristics in the polarized light at a liquid penetration into delaminated polymer layers is found. Measuring parameters and critical uncertainties are defined.

Porous polymer networks and ion-exchange media and metal-polymer composites made therefrom

Energy Technology Data Exchange (ETDEWEB)

Kanatzidis, Mercouri G.; Katsoulidis, Alexandros

2016-10-18

Porous polymeric networks and composite materials comprising metal nanoparticles distributed in the polymeric networks are provided. Also provided are methods for using the polymeric networks and the composite materials in liquid- and vapor-phase waste remediation applications. The porous polymeric networks, are highly porous, three-dimensional structures characterized by high surface areas. The polymeric networks comprise polymers polymerized from aldehydes and phenolic molecules.

New transparent conductive metal based on polymer composite

Energy Technology Data Exchange (ETDEWEB)

Keshavarz Hedayati, Mehdi; Jamali, Mohammad [Nanochemistry and Nanoengineering, Institute for Materials Science, Faculty of Engineering, Christian-Albrechts-University, Kiel (Germany); Strunkus, Thomas; Zaporochentko, Vladimir; Faupel, Franz [Multicomponent Materials, Institute for Materials Science, Faculty of Engineering, Christian-Albrechts-University, Kiel (Germany); Elbahri, Mady [Nanochemistry and Nanoengineering, Institute for Materials Science, Faculty of Engineering, Christian-Albrechts-University, Kiel (Germany); Helmholtz-Zentrum Geesthacht GmbH, Institute of Polymer Research, Nanochemistry and Nanoengineering (Germany)

2011-07-01

Currently great efforts are made to develop new kind of transparent conductors (TCs) to replace ITO. In this regard different materials and composites have been proposed and studied including conductive polymers, carbon nanotubes (CNTs), metal grids, and random networks of metallic nanowires. But so far none of them could be used as a replacing material, since either they are either fragile and brittle or their electrical conductivity is below the typical ITO. Thin metallic films due to their high electrical conductivity could be one of the best replacing materials for ITO, however their poor transparency makes their application as TCs limited. Here we design and fabricate a new polymeric composite coating which enhances the transparency of the thin metal film up to 100% relative to the initial value while having a high electrical conductivity of typical metals. Therefore our proposed device has a great potential to be used as new transparent conductor.

Analysis of mtDNA sequence variants in colorectal adenomatous polyps

Directory of Open Access Journals (Sweden)

Grizzle William

2010-10-01

Full Text Available Abstract Colorectal tumors mostly arise from sporadic adenomatous polyps. Polyps are defined as a mass of cells that protrudes into the lumen of the colon. Adenomatous polyps are benign neoplasms that, by definition display some characteristics of dysplasia. It has been shown that polyps were benign tumors which may undergo malignant transformation. Adenomatous polyps have been classified into three histologic types; tubular, tubulovillous, and villous with increasing malignant potential. The ability to differentially diagnose these colorectal adenomatous polyps is important for therapeutic intervention. To date, little efforts have been directed to identifying genetic changes involved in adenomatous polyps. This study was designed to examine the relevance of mitochondrial genome alterations in the three adenomatous polyps. Using high resolution restriction endonucleases and PCR-based sequencing, fifty-seven primary fresh frozen tissues of adenomatous polyps (37 tumors and 20 matched surrounding normal tissues obtained from the southern regional Cooperative Human Tissue Network (CHTN and Grady Memorial Hospital at Atlanta were screened with three mtDNA regional primer pairs that spanned 5.9 kbp. Results from our data analyses revealed the presence of forty-four variants in some of these mitochondrial genes that the primers spanned; COX I, II, III, ATP 6, 8, CYT b, ND 5, 6 and tRNAs. Based on the MITODAT database as a sequence reference, 25 of the 44 (57% variants observed were unreported. Notably, a heteroplasmic variant C8515G/T in the MT-ATP 8 gene and a germline variant 8327delA in the tRNAlys was observed in all the tissue samples of the three adenomatous polyps in comparison to the referenced database sequence. A germline variant G9055A in the MT-ATP 6 gene had a frequency of 100% (17/17 in tubular and 57% (13/23 in villous adenomas; no corresponding variant was in tubulovillous adenomas. Furthermore, A9006G variant at MT-ATP 6 gene was

Endometrial polyps and associated factors in Danish women aged 36-74 years

DEFF Research Database (Denmark)

Dreisler, Eva; Sorensen, Soren Stampe; Lose, Gunnar

2008-01-01

, the following was positively associated with endometrial polyps: current use of hormone therapy (odds ratio, 2.81; 95% CI, 1.29-6.13) and being overweight (body mass index > 25 kg/m(2)) (odds ratio, 2.06; 95% CI, 1.12-3.79) (postmenopausal women). Negatively associated was use of oral contraceptive pills (odds...... women were positively associated, whereas the use of oral contraceptive pills was negatively associated with endometrial polyps. Hypertension and cervical polyps were not associated with endometrial polyps. Endometrial polyps were infrequently related to premalignant and malignant disease....

Facile construction of terpridine-based metallo-polymers in hydrogels, crystals and solutions directed by metal ions.

Science.gov (United States)

Li, Yajuan; Guo, Jiangbo; Dai, Bo; Geng, Lijun; Shen, Fengjuan; Zhang, Yajun; Yu, Xudong

2018-07-01

Driven by tunable metal-ligand interactions, a polydentate ligand TC containing terpyridine and carboxylic acid units was developed to construct metallo-polymers that showed multiple aggregation modes with controlled macroscopic properties. In the presence of different kind of Zn 2+ ions or NaOH, TC could form metallo-polymers via π-π stacking and metal-ligand interaction that further trapped water molecules, resulting in hydrogels and crystals. Moreover, these TC/Zn 2+ hydrogels could transform to soluble and fluorescent aggregates in the presence of NaOH due to the formation of binuclear metallo-polymers with enhanced ICT emission. The metal-ligand interactions tuned by different metal salts in gels, crystals, and sols were also studied and illustrated in detail, it was also proved that water was an essential linker for constructing Na + -based metallo-polymers from the TC/NaOH crystal data. This work demonstrated the engineered coordination pathways in generating controllable hydrogels and metallo-polymers for the first time, which led to novel approach for facilely constructing a number of hydrogels with tailorable macroscopic properties. Copyright © 2018 Elsevier Inc. All rights reserved.

Correlation of morphology and barrier properties of thin microwave plasma polymer films on metal substrate

International Nuclear Information System (INIS)

Barranco, V.; Carpentier, J.; Grundmeier, G.

2004-01-01

The barrier properties of thin model organosilicon plasma polymers layers on iron are characterised by means of electrochemical impedance spectroscopy (EIS). Tailored thin plasma polymers of controlled morphology and chemical composition were deposited from a microwave discharge. By the analysis of the obtained impedance diagrams, the evolution of the water uptake φ, coating resistance and polymer capacitance with immersion time were monitored and the diffusion coefficients of the water through the films were calculated. The impedance data correlated well with the chemical structure and morphology of the plasma polymer films with a thickness of less than 100 nm. The composition of the films were determined by means of infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The morphology of the plasma polymer surface and the interface between the plasma polymer and the metal were characterised using atomic force microscopy (AFM). It could be shown that, at higher pressure, the film roughness increases which is probably due to the adsorption of plasma polymer nanoparticles formed in the plasma bulk and the faster film growth. This leads to voids with a size of a few tens of nanometers at the polymer/metal interface. The film roughness increases from the interface to the outer surface of the film. By lowering the pressure and thereby slowing the deposition rate, the plasma polymers perfectly imitate the substrate topography and lead to an excellent blocking of the metal surface. Moreover, the ratio of siloxane bonds to methyl-silyl groups increases which implies that the crosslink density is higher at lower deposition rate. The EIS data consistently showed higher coating resistance as well as lower interfacial capacitance values and a better stability over time for the film deposited at slower pressure. The diffusion coefficient of water in thin and ultra-thin plasma

An umbilical polyp in an infant.

Science.gov (United States)

Swanson, David L; Pakzad, Betty

2005-10-01

The persistence at birth of the omphalomesenteric (vitelline) duct may result in life-threatening consequences. Early identification of this congenital anomaly is essential for prompt surgical treatment to eliminate the risk of prolapse and herniation. A neonatal umbilical polyp may indicate the presence of an omphalomesenteric duct remnant. We describe the diagnosis and surgical treatment of an infant with an umbilical polyp. We also present an overview of the diagnosis and treatment of vitelline duct remnants and their associated anomalies.

Role of β-hydroxybutyrate, its polymer poly-β-hydroxybutyrate and inorganic polyphosphate in mammalian health and disease

Directory of Open Access Journals (Sweden)

Elena N. Dedkova

2014-07-01

Full Text Available We provide a comprehensive review of the role of β-hydroxybutyrate (β-OHB, its linear polymer poly-β-hydroxybutyrate (PHB and inorganic polyphosphate (polyP in mammalian health and disease. β-OHB is a metabolic intermediate that constitutes 70% of ketone bodies produced during ketosis. Although ketosis has been generally considered as an unfavorable pathological state (e.g. diabetic ketoacidosis in type-1 diabetes mellitus, it has been suggested that induction of mild hyperketonemia may have certain therapeutic benefits. β-OHB is synthesized in the liver from acetyl-CoA by β-hydroxybutyrate dehydrogenase and can be used as alternative energy source. Elevated levels of PHB are associated with pathological states. In humans, short-chain, complexed PHB (cPHB is found in a wide variety of tissues and in atherosclerotic plaques. Plasma cPHB concentrations correlate strongly with atherogenic lipid profiles, and PHB tissue levels are elevated in type-1 diabetic animals. However, little is known about mechanisms of PHB action especially in the heart. In contrast to β-OHB, PHB is a water-insoluble, amphiphilic polymer that has high intrinsic viscosity and salt-solvating properties. cPHB can form non-specific ion channels in planar lipid bilayers and liposomes. PHB can form complexes with polyP and Ca2+ which increases membrane permeability. The biological roles played by polyP, a ubiquitous phosphate polymer with ATP-like bonds, have been most extensively studied in prokaryotes, however polyP has recently been linked to a variety of functions in mammalian cells, including blood coagulation, regulation of enzyme activity in cancer cells, cell proliferation, apoptosis and mitochondrial ion transport and energy metabolism. Recent evidence suggests that polyP is a potent activator of the mitochondrial permeability transition pore in cardiomyocytes and may represent a hitherto unrecognized key structural and functional component of the mitochondrial

Computer-assisted polyp matching between optical colonoscopy and CT colonography: a phantom study

Science.gov (United States)

Roth, Holger R.; Hampshire, Thomas E.; Helbren, Emma; Hu, Mingxing; Vega, Roser; Halligan, Steve; Hawkes, David J.

2014-03-01

Potentially precancerous polyps detected with CT colonography (CTC) need to be removed subsequently, using an optical colonoscope (OC). Due to large colonic deformations induced by the colonoscope, even very experienced colonoscopists find it difficult to pinpoint the exact location of the colonoscope tip in relation to polyps reported on CTC. This can cause unduly prolonged OC examinations that are stressful for the patient, colonoscopist and supporting staff. We developed a method, based on monocular 3D reconstruction from OC images, that automatically matches polyps observed in OC with polyps reported on prior CTC. A matching cost is computed, using rigid point-based registration between surface point clouds extracted from both modalities. A 3D printed and painted phantom of a 25 cm long transverse colon segment was used to validate the method on two medium sized polyps. Results indicate that the matching cost is smaller at the correct corresponding polyp between OC and CTC: the value is 3.9 times higher at the incorrect polyp, comparing the correct match between polyps to the incorrect match. Furthermore, we evaluate the matching of the reconstructed polyp from OC with other colonic endoluminal surface structures such as haustral folds and show that there is a minimum at the correct polyp from CTC. Automated matching between polyps observed at OC and prior CTC would facilitate the biopsy or removal of true-positive pathology or exclusion of false-positive CTC findings, and would reduce colonoscopy false-negative (missed) polyps. Ultimately, such a method might reduce healthcare costs, patient inconvenience and discomfort.

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

Science.gov (United States)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

Method and apparatus for selective capture of gas phase analytes using metal .beta.-diketonate polymers

Science.gov (United States)

Harvey, Scott D [Kennewick, WA

2011-06-21

A process and sensor device are disclosed that employ metal .beta.-diketonate polymers to selectively capture gas-phase explosives and weaponized chemical agents in a sampling area or volume. The metal .beta.-diketonate polymers can be applied to surfaces in various analytical formats for detection of: improvised explosive devices, unexploded ordinance, munitions hidden in cargo holds, explosives, and chemical weapons in public areas.

Heterobimetallic coordination polymers involving 3d metal complexes and heavier transition metals cyanometallates

Energy Technology Data Exchange (ETDEWEB)

Peresypkina, Eugenia V. [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Samsonenko, Denis G. [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Vostrikova, Kira E., E-mail: vosk@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); LMI, Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France)

2015-04-15

The results of the first steps in the design of coordination polymers based on penta- and heptacyanometallates of heavier d transitions metals are presented. The 2D structure of the coordination polymers: [(Mn(acacen)){sub 2}Ru(NO)(CN){sub 5}]{sub n} and two complexes composed of different cyanorhenates, [Ni(cyclam)]{sub 2}[ReO(OH)(CN){sub 4}](ClO{sub 4}){sub 2}(H{sub 2}O){sub 1.25} and [Cu(cyclam)]{sub 2}[Re(CN){sub 7}](H{sub 2}O){sub 12}, was confirmed by single crystal XRD study, the rhenium oxidation state having been proved by the magnetic measurements. An amorphism of [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2} (M=Ni, Cu) polymers does not allow to define strictly their dimensionality and to model anisotropic magnetic behavior of the compounds. However, with high probability a honey-comb like layer structure could be expected for [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2} complexes, studied in this work, because such an arrangement is the most common among the bimetallic assemblies of hexa- and octacyanometallates with a ratio [M(cyclam)]/[M(CN){sub n}]=3/2. For the first time was prepared and fully characterized a precursor (n-Bu{sub 4}N){sub 2}[Ru(NO)(CN){sub 5}], soluble in organic media. - Graphical abstract: The very first results in the design of 2D coordination polymers based on penta- and heptacyanometallates of 4d and5d transitions metals are presented. - Highlights: • Design of coordination polymers based on penta- and heptacyanometallates. • New Ru and Re cyanide based heterobimetallic coordination complexes. • Hydrolysis and ox/red processes involving [Re(CN){sub 7}]{sup 3+} during crystallization. • High magnetic anisotropy of [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2}(H{sub 2}O){sub n}, M=Cu, Ni, complexes.

Spontaneous resolution of hemorrhagic polyps of the true vocal fold.

Science.gov (United States)

Klein, Adam M; Lehmann, Marcus; Hapner, Edie R; Johns, Michael M

2009-01-01

Hemorrhagic polyps are the most common benign lesions surgically removed from the vocal folds. Although this modality does offer satisfactory results in most of the cases, there is a subset of polyps that seems to resolve with conservative therapy. This study was performed to examine this subset of polyps. Thirty-four consecutive subjects diagnosed with hemorrhagic polyps of the true vocal fold were retrospectively reviewed to determine the incidence of spontaneous resolution of the lesions with nonsurgical therapy. Sixteen subjects began conservative therapy, consisting of voice therapy and proper vocal hygiene, often while awaiting an optimal personal time for surgical intervention. Of these subjects, nine (56.3%) experienced a resolution of their lesion and symptoms without undergoing surgical therapy. Surgical removal of hemorrhagic polyps is often considered the standard of treatment for these benign lesions. However, these observations support a regimen of voice therapy and observation in select cases.

Congenital urethral polyps: a report of two cases

International Nuclear Information System (INIS)

Cano, D.; Vivas, I.; Torres, E.; Garcia, L.; Fernandez-Villa, T.

1999-01-01

Congenital urethral polyps are uncommon lesions, very few cases of which have been previously reported in the literature. We present two cases of congenital urethral polyps in children, describing the clinical and radiological features and the diagnostic method employed, as well as reviewing the literature. (Author) 6 refs

Polymer powder adhesion to metallic surface improvement with plasma

International Nuclear Information System (INIS)

Hladik, J.; Pichal, J.; Spatenka, P.; Pichal, J.; Spatenka, P.

2008-01-01

Useful method for corrosion prevention is coating of a base material with a suitable substance. It performs a barrier between the base material and its environment. Great attractions in this field have found polymers, among them polyethylenes (PE). Due to the low adhesion grade of unmodified polymer powder or granules the application of any modification process increasing the adhesion grade is crucial. At present there is no universal approach to polymer adhesion improvement and there have been employed various quite different techniques. Our research employed the PE adhesion improvement by plasma modification. There were used two plasma reactors - the microwave low pressure reactor and the atmospheric reactor employing dielectric barrier discharge (DBD). The adhesion of the powder was determined by measurement of strength force demanded for displacement of the PE-metal joint

An evidence-based treatment algorithm for colorectal polyp cancers: results from the Scottish Screen-detected Polyp Cancer Study (SSPoCS).

Science.gov (United States)

Richards, C H; Ventham, N T; Mansouri, D; Wilson, M; Ramsay, G; Mackay, C D; Parnaby, C N; Smith, D; On, J; Speake, D; McFarlane, G; Neo, Y N; Aitken, E; Forrest, C; Knight, K; McKay, A; Nair, H; Mulholland, C; Robertson, J H; Carey, F A; Steele, Rjc

2018-02-01

Colorectal polyp cancers present clinicians with a treatment dilemma. Decisions regarding whether to offer segmental resection or endoscopic surveillance are often taken without reference to good quality evidence. The aim of this study was to develop a treatment algorithm for patients with screen-detected polyp cancers. This national cohort study included all patients with a polyp cancer identified through the Scottish Bowel Screening Programme between 2000 and 2012. Multivariate regression analysis was used to assess the impact of clinical, endoscopic and pathological variables on the rate of adverse events (residual tumour in patients undergoing segmental resection or cancer-related death or disease recurrence in any patient). These data were used to develop a clinically relevant treatment algorithm. 485 patients with polyp cancers were included. 186/485 (38%) underwent segmental resection and residual tumour was identified in 41/186 (22%). The only factor associated with an increased risk of residual tumour in the bowel wall was incomplete excision of the original polyp (OR 5.61, p=0.001), while only lymphovascular invasion was associated with an increased risk of lymph node metastases (OR 5.95, p=0.002). When patients undergoing segmental resection or endoscopic surveillance were considered together, the risk of adverse events was significantly higher in patients with incomplete excision (OR 10.23, p<0.001) or lymphovascular invasion (OR 2.65, p=0.023). A policy of surveillance is adequate for the majority of patients with screen-detected colorectal polyp cancers. Consideration of segmental resection should be reserved for those with incomplete excision or evidence of lymphovascular invasion. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Posterior urethral polyps and review of literature

Directory of Open Access Journals (Sweden)

Prashant Jain

2007-01-01

Full Text Available Urethral polyp is a rare finding in young children. Fibroepithelial polyps of the urethra are usually diagnosed during the first decade of life. They present with obstruction, voiding dysfunction and hematuria. They can be associated with other congenital urinary tract anomalies. They are usually benign fibroepithelial lesions with no tendency to recur and are treated by surgical ablation, fulguration or laser therapy.

Adhesion and adhesion changes at the copper metal-(acrylonitrile-butadiene-styrene) polymer interface

NARCIS (Netherlands)

Kisin, S.; Varst, van der P.G.T.; With, de G.

2007-01-01

It is known that the adhesive strength of metallic films on polymer substrates often changes in the course of time. To study this effect in more detail, the adhesion energy of sputtered and galvanically strengthened copper coatings on acrylonitrile–butadiene–styrene polymer substrate was determined

Appendiceal Adenocarcinoma Presenting as a Rectal Polyp

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Erin Fitzgerald

2016-02-01

Full Text Available Appendiceal adenocarcinoma typically presents as an incidentally noted appendiceal mass, or with symptoms of right lower quadrant pain that can mimic appendicitis, but local involvement of adjacent organs is uncommon, particularly as the presenting sign. We report on a case of a primary appendiceal cancer initially diagnosed as a rectal polyp based on its appearance in the rectal lumen. The management of the patient was in keeping with standard practice for a rectal polyp, and the diagnosis of appendiceal adenocarcinoma was made intraoperatively. The operative strategy had to be adjusted due to this unexpected finding. Although there are published cases of appendiceal adenocarcinoma inducing intussusception and thus mimicking a cecal polyp, there are no reports in the literature describing invasion of the appendix through the rectal wall and thus mimicking a rectal polyp. The patient is a 75-year-old female who presented with spontaneous hematochezia and, on colonoscopy, was noted to have a rectal polyp that appeared to be located within a diverticulum. When endoscopic mucosal resection was not successful, she was referred to colorectal surgery for a low anterior resection. Preoperative imaging was notable for an enlarged appendix adjacent to the rectum. Intraoperatively, the appendix was found to be densely adherent to the right lateral rectal wall. An en bloc resection of the distal sigmoid colon, proximal rectum and appendix was performed, with pathology demonstrating appendiceal adenocarcinoma that invaded through the rectal wall. The prognosis in this type of malignancy weighs heavily on whether or not perforation and spread throughout the peritoneal cavity have occurred. In this unusual presentation, an en bloc resection is required for a complete resection and to minimize the risk of peritoneal spread. Unusual appearing polyps do not always originate from the bowel wall. Abnormal radiographic findings adjacent to an area of

Radiation crosslinking of polymers with segregated metallic particles. Final report, June 1, 1971--September 30, 1973

International Nuclear Information System (INIS)

Corneliussen, R.D.; Kamel, I.; Kusy, R.P.

1973-01-01

Through the past four years of research, a new approach to fabricating conductive polymer/metal composites has been developed. This approach consists of compacting mixtures of polymer and metal powders and then stabilizing the composite through radiation-induced crosslinking. The result is a mechanically strong, conductive materials consisting of two intertwining networks. One is a massive network consisting of fused crosslinked, large (greater than 100 μ) polymer particles while the other is a fine network of small, metallic particles (greater than 10 μ). Nine different systems including crystalline, amorphous, and rubbery polymers were studied. Processing at this time is limited to compression molding in a closed die because of network stability problems. Costs for processing were estimated at about $6.00/lb compared to $50.00 and up for commercial material based on random networks. (U.S.)

Use of X-ray fluorescence for metal determination in polymers

International Nuclear Information System (INIS)

Guidorizzi, Lorenza

1996-01-01

X-Ray fluorescence spectrometry was used to determine metals and non-metals in polyester polymers. The greatest advantage of this technique over others like Atomic Absorption or Plasma Emission is that no sample previous treatment (like calcination or acid digestion) is required. Other advantage of this method is its fastness allowing a complete analysis in just few minutes. On the other hand, this method requires metals higher than 15 ppm. Below those values there is a loss of the analysis' precision. Another advantage of this technique is the possibility of making qualitative metal analysis, scanning unknown samples and identifying the found peaks automatically. (author)

Clinical and pathological characteristics of colorectal polyps in ...

African Journals Online (AJOL)

Background & Aim: Colon polyps are important lesions and a concern because of the potential for colorectal cancer. Colorectal carcinoma is one of the most common causes of cancer-related deaths in Iranian population. The distribution of polyps in the colon may affect the efficacy of a screening modality. The aim of this ...

Determination of the optical constants of polymer light-emitting diode films from single reflection measurements

International Nuclear Information System (INIS)

Zhu Dexi; Shen Weidong; Ye Hui; Liu Xu; Zhen Hongyu

2008-01-01

We present a simple and fast method to determine the optical constant and physical thickness of polymer films from a single reflectivity measurement. A self-consistent dispersion formula of the Forouhi-Bloomer model was introduced to fit the measured spectral curves by a modified 'Downhill' simplex algorithm. Four widely used polymer light-emitting diodes materials: poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene], poly(9,9-dioctylfluoreny-2,7-diyl) (PFO), poly(N-vinyl carbazole) and poly(3,4-ethylene dioxythiophene) : poly(styrenesulfonate) were investigated by this technique. The refractive indices over the whole visible region as well as the optical band gap extracted by this method agree well with those reported in the literature. The determined physical thicknesses present a deviation less than 4% compared with the experimental values measured by the stylus profiler. The influence of scattering loss on the fitted results is discussed to demonstrate the applicability of this technology for polymer films.

Recovery of metals from simulant spent lithium-ion battery as organophosphonate coordination polymers in aqueous media

Energy Technology Data Exchange (ETDEWEB)

Perez, Emilie; Andre, Marie-Laure; Navarro Amador, Ricardo [ICSM, Institut de Chimie Séparative de Marcoule, UMR 5257, CEA/CNRS/ENSCM/UM, Bât 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France); Hyvrard, François; Borrini, Julien [SARPI VEOLIA, Direction Technique et Innovations, Zone portuaire de Limay-Porcheville, 427 route du Hazay, 78520 Limay (France); Carboni, Michaël, E-mail: michael.carboni@cea.fr [ICSM, Institut de Chimie Séparative de Marcoule, UMR 5257, CEA/CNRS/ENSCM/UM, Bât 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France); Meyer, Daniel [ICSM, Institut de Chimie Séparative de Marcoule, UMR 5257, CEA/CNRS/ENSCM/UM, Bât 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France)

2016-11-05

Highlights: • Original waste disposal strategies for battery. • Precipitation of metals as coordination polymers. • Organo-phosphonate coordination polymers. • Selective extraction of manganese or co-precipitation of manganese/cobalt. • The recycling process give a promising application on any waste solution. - Abstract: An innovative approach is proposed for the recycling of metals from a simulant lithium-ion battery (LIBs) waste aqueous solution. Phosphonate organic linkers are introduced as precipitating agents to selectively react with the metals to form coordination polymers from an aqueous solution containing Ni, Mn and Co in a hydrothermal process. The supernatant is analyzed by ICP-AES to quantify the efficiency and the selectivity of the precipitation and the materials are characterized by Scanning Electron Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Thermogravimetric Analyses (TGA) and nitrogen gas sorption (BET). Conditions have been achieved to selectively precipitate Manganese or Manganese/Cobalt from this solution with a high efficiency. This work describes a novel method to obtain potentially valuable coordination polymers from a waste metal solution that can be generalized on any waste solution.

Determination of the trap-assisted recombination strength in polymer light emitting diodes

NARCIS (Netherlands)

Kuik, M.; Nicolai, H.T.; Lenes, M.; Wetzelaer, G.-J.A.H.; Lu, M.; Blom, P.W.M.

2011-01-01

The recombination processes in poly(p -phenylene vinylene) based polymer light-emitting diodes (PLEDs) are investigated. Photogenerated current measurements on PLED device structures reveal that next to the known Langevin recombination also trap-assisted recombination is an important recombination

Association between Laryngeal Pepsin Levels and the Presence of Vocal Fold Polyps.

Science.gov (United States)

Wang, Lu; Tan, Jia-Jie; Wu, Ting; Zhang, Rui; Wu, Jia-Nuan; Zeng, Fang-Fang; Liu, You-Li; Han, Xiao-Yan; Li, Yan-Fei; Li, Xiang-Ping

2017-01-01

Objective To determine whether pepsin, the main component of refluxed gastric contents, is significantly associated with vocal fold polyps and to evaluate the diagnostic value of pepsin in vocal fold polyps' tissues. Study Design Cross-sectional study. Setting Nanfang Hospital of Southern Medical University. Subjects and Methods The study included 32 patients with vocal fold polyps and 16 healthy controls between 2011 and 2012. Reflux symptom index and reflux finding score assessments, 24-hour combined multichannel intraluminal impedance and pH monitoring, and biopsy of the vocal fold polyp tissues or posterior laryngeal mucosa (healthy controls) for immunohistochemical pepsin staining were performed. Results The expression of pepsin was significantly higher in patients with vocal fold polyps than in controls (28/32, 75% vs 5/16, 31.25%; P vocal fold polyps formation. In addition, pepsin immunohistochemical analysis of polyp biopsy samples appears to be a more sensitive and effective test for diagnosing laryngopharyngeal reflux than the reflux symptom index, the reflux finding score, and 24-hour pH monitoring in a clinical setting.

Antral hyperplastic polyp causing intermittent gastric outlet obstruction: Case report

Directory of Open Access Journals (Sweden)

Kurtkaya-Yapicier Ozlem

2003-06-01

Full Text Available Abstract Background Hyperplastic polyps are the most common polypoid lesions of the stomach. Rarely, they cause gastric outlet obstruction by prolapsing through the pyloric channel, when they arise in the prepyloric antrum. Case presentation A 62-year-old woman presented with intermittent nausea and vomiting of 4 months duration. Upper gastrointestinal endoscopy revealed a 30 mm prepyloric sessile polyp causing intermittent gastric outlet obstruction. Following submucosal injection of diluted adrenaline solution, the polyp was removed with a snare. Multiple biopsies were taken from the greater curvature of the antrum and the corpus. Rapid urease test for Helicobacter pylori yielded a negative result. Histopathologic examination showed a hyperplastic polyp without any evidence of malignancy. Biopsies of the antrum and the corpus revealed gastritis with neither atrophic changes nor Helicobacter pylori infection. Follow-up endoscopy after a 12-week course of proton pomp inhibitor therapy showed a complete healing without any remnant tissue at the polypectomy site. The patient has been symptom-free during 8 months of follow-up. Conclusions Symptomatic gastric polyps should be removed preferentially when they are detected at the initial diagnostic endoscopy. Polypectomy not only provides tissue to determine the exact histopathologic type of the polyp, but also achieves radical treatment.

Water-Induced Degradation of Polymer Solar Cells Studied by (H2O)-O-18 Labeling

DEFF Research Database (Denmark)

Norrman, Kion; Gevorgyan, Suren; Krebs, Frederik C

2009-01-01

Water-induced degradation of polymer photovoltaics based on the active materials poly(3-hexylthiophene) (P3HT) or poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) was studied. The solar cell devices comprised a bulk heterojunction formed by the active material and [6,6]-phenyl......-C61-butyric acid methyl ester (PCBM) in a standard device geometry. The use of H218O in conjunction with time-of-flight secondary ion mass spectrometry enabled mapping of the parts of the device that were induced by water. A comparison was made between the two active materials and between devices...

Seasonality in polyps of a tropical cubozoan: A latina nr mordens.

Directory of Open Access Journals (Sweden)

Robert Courtney

Full Text Available A latina nr mordens have been located in large predictable spawning aggregations near Osprey Reef in the Coral Sea eight to ten days after a full moon; however, polyps have never been located in-situ. The polyp stage contributes to the abundance of medusae through asexual reproduction and metamorphosis, and may influence the periodicity of medusae by metamorphosis of the polyp. To elucidate the relationship between medusae periodicity and polyp ecology, polyps were exposed to thermal and osmotic treatments in order to determine the theoretical environmental limits to their distribution. Maximum fecundity occurred in thermal treatments of 21 to 25ºC and the theoretical minimum thermal requirement for population stability was approximately 17ºC. Polyps were also exposed to five feeding regimes and fecundity was found to be positively correlated with feeding frequency. Thermal and osmotic variations did not induce metamorphosis in this species, however, reduced food did. The implications of asexual reproduction and cues for metamorphosis in relation to population dynamics of this species are discussed.

A supramolecular miktoarm star polymer based on porphyrin metal complexation in water.

Science.gov (United States)

Hou, Zhanyao; Dehaen, Wim; Lyskawa, Joël; Woisel, Patrice; Hoogenboom, Richard

2017-07-25

A novel supramolecular miktoarm star polymer was successfully constructed in water from a pyridine end-decorated polymer (Py-PmDEGA) and a metalloporphyrin based star polymer (ZnTPP-(PEG) 4 ) via metal-ligand coordination. The Py-PmDEGA moiety was prepared via a combination of reversible addition-fragmentation chain transfer polymerization (RAFT) and subsequent aminolysis and Michael addition reactions to introduce the pyridine end-group. The ZnTPP(PEG) 4 star-polymer was synthesized by the reaction between tetrakis(p-hydroxyphenyl)porphyrin and toluenesulfonyl-PEG, followed by insertion of a zinc ion into the porphyrin core. The formation of a well-defined supramolecular AB 4 -type miktoarm star polymer was unambiguously demonstrated via UV-Vis spectroscopic titration, isothermal titration calorimetry (ITC) and diffusion ordered NMR spectroscopy (DOSY).

Selective micro metallization of polymers for biomedical and medical application

DEFF Research Database (Denmark)

Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

Integration of micro/nano metallic structures in polymer devices is a broad multi-disciplinary research field, consisting of various combinations of mechanical, chemical and physical fabrication methods. Some of these combinations have been known for years and other combinations or methods are ve...

Ion induced modification of polymers at energies between 100 keV and 1 GeV applied for optical waveguides and improved metal adhesion

International Nuclear Information System (INIS)

Rueck, D.M.

2000-01-01

Polymers are a class of materials widely used for a broad field of applications. Ion irradiation ranging from several eV to GeV is a quite efficient tool to modify the properties of polymers like wettability, optical properties, adhesion between metal and polymer surfaces. In this paper ion induced chemical changes of polymers will be discussed in relation to the modified macroscopic properties. In the field of optical telecommunication, polymers are discussed as a new class of materials for the fabrication of passive optical devices. Ion irradiation is a promising method to generate structures with a modified index of refraction, which is necessary for the guidance of light with different wavelengths in optical devices. Modified optical properties of different polymers under ion irradiation will be discussed. Analytical investigations like infrared measurements and measurement of the outgassing reaction products during irradiation will be discussed to interpret the chemical changes of the polymers. Metallization of polymers is of interest in several fields of application like for multilayer systems in microtechnology or casings for radiation shielding for example. Ion beam mixing at low energies is a promising method to improve the metal/polymer adhesion. Also ion irradiation at high energies applied to a metal/polymer multilayer can improve the adhesion of a metal layer to a polymer surface, if not sufficient. Different metal/polymer systems will be presented as well as specific applications

Structure and signaling at hydroid polyp-stolon junctions, revisited

Directory of Open Access Journals (Sweden)

Katherine L. Harmata

2015-09-01

Full Text Available The gastrovascular system of colonial hydroids is central to homeostasis, yet its functional biology remains poorly understood. A probe (2′,7′-dichlorodihydrofluorescein diacetate for reactive oxygen species (ROS identified fluorescent objects at polyp-stolon junctions that emit high levels of ROS. A nuclear probe (Hoechst 33342 does not co-localize with these objects, while a mitochondrial probe (rhodamine 123 does. We interpret these objects as mitochondrion-rich cells. Confocal microscopy showed that this fluorescence is situated in large columnar cells. Treatment with an uncoupler (2,4-dinitrophenol diminished the ROS levels of these cells relative to background fluorescence, as did removing the stolons connecting to a polyp-stolon junction. These observations support the hypothesis that the ROS emanate from mitochondrion-rich cells, which function by pulling open a valve at the base of the polyp. The open valve allows gastrovascular fluid from the polyp to enter the stolons and vice versa. The uncoupler shifts the mitochondrial redox state in the direction of oxidation, lowering ROS levels. By removing the stolons, the valve is not pulled open, metabolic demand is lowered, and the mitochondrion-rich cells slowly regress. Transmission electron microscopy identified mitochondrion-rich cells adjacent to a thick layer of mesoglea at polyp-stolon junctions. The myonemes of these myoepithelial cells extend from the thickened mesoglea to the rigid perisarc on the outside of the colony. The perisarc thus anchors the myoepithelial cells and allows them to pull against the mesoglea and open the lumen of the polyp-stolon junction, while relaxation of these cells closes the lumen.

Inverted Lymphoglandular Polyp in Descending Colon

Directory of Open Access Journals (Sweden)

Shengmei Zhou

2015-01-01

Full Text Available A 47-year-old male with a history of left colon cancer, status post left colon resection for 12 years, presented with rectal bleeding. Colonoscopic examination revealed an 8 mm sessile polyp in the proximal descending colon. Microscopic examination showed that the surface of this polyp was covered with a layer of normal colonic mucosa with focal surface erosion. In the submucosal layer, an intimate admixture of multiple cystically dilated glands and prominent lymphoid aggregates with germinal centers was seen. The glands were lined by columnar epithelium. Immunohistochemical staining showed the glands were positive for CK20 and CDX2 and negative for CK7, with a low proliferative index, mostly consistent with reactive colonic glands. The patient remained asymptomatic after one-year follow-up. A review of the literature shows very rare descriptions of similar lesions, but none fits exactly this pattern. We would designate this inverted lymphoglandular polyp and present this case to raise the awareness of recognizing this unusual histological entity.

Transanal endoscopic microsurgery for giant polyps of the rectum

DEFF Research Database (Denmark)

Levic, K; Bulut, O; Hesselfeldt, P

2014-01-01

in the rectum. We present our results with TEM in the removal of giant polyps equal or greater than 4 cm in diameter. METHODS: In the period between 1998 and 2012, TEM was performed in 39 patients with rectal polyps measuring at least 4 cm in diameter. Transrectal ultrasound and/or magnetic resonance imaging......, these recurrences were treated with endoscopic removal or re-TEM. The remaining 5 underwent total mesorectal excision and/or chemotherapy. CONCLUSIONS: Full-thickness TEM provides a safe and efficient treatment for excision of giant polyps. In case of unexpected cancer, TEM can be curative. Local recurrence can...

Polymer Surface Engineering for Efficient Printing of Highly Conductive Metal Nanoparticle Inks.

Science.gov (United States)

Agina, Elena V; Sizov, Alexey S; Yablokov, Mikhail Yu; Borshchev, Oleg V; Bessonov, Alexander A; Kirikova, Marina N; Bailey, Marc J A; Ponomarenko, Sergei A

2015-06-10

An approach to polymer surface modification using self-assembled layers (SALs) of functional alkoxysilanes has been developed in order to improve the printability of silver nanoparticle inks and enhance adhesion between the metal conducting layer and the flexible polymer substrate. The SALs have been fully characterized by AFM, XPS, and WCA, and the resulting printability, adhesion, and electrical conductivity of the screen-printed metal contacts have been estimated by cross-cut tape test and 4-point probe measurements. It was shown that (3-mercaptopropyl)trimethoxysilane SALs enable significant adhesion improvements for both aqueous- and organic-based silver inks, approaching nearly 100% for PEN and PDMS substrates while exhibiting relatively low sheet resistance up to 0.1 Ω/sq. It was demonstrated that SALs containing functional -SH or -NH2 end groups offer the opportunity to increase the affinity of the polymer substrates to silver inks and thus to achieve efficient patterning of highly conductive structures on flexible and stretchable substrates.

Prevalence of colonic polyp and its predictors in patients with acromegaly

Directory of Open Access Journals (Sweden)

Purnima Agarwal

2016-01-01

Full Text Available Background: There are conflicting data regarding the prevalence of colorectal polyp in patients with acromegaly. Subjects and Methods: Consecutive forty-seven acromegalic patients (21 men, 26 women, with a mean age of (40 ± 12 years attending endocrinology outpatient department underwent full colonoscopy. All the patients underwent clinical and biochemical evaluation (glucose suppressed growth hormone (GH, Insulin-like growth factor-1 [IGF-1], fasting insulin, and glucose. The control group (n = 120 for colonoscopy was adult subjects undergoing evaluation for symptoms of irritable bowel syndrome. Clinical and biochemical parameters in acromegalic patients with colonic polyp were compared to those without a polyp. Results: Patients with acromegaly had significantly higher prevalence of colonic polyp as compared to control subjects (10.6% vs. 0.8%. None of the patients with polyp had skin tags. There was no significant difference between subjects with and without colonic polyp in duration of illness, basal, and glucose-suppressed GH and most recent IGF-1. Fasting blood sugar was significantly higher (P < 0.05 in adenoma group after adjusting for age, body mass index (BMI, and insulin levels. Patients in adenoma group showed a trend toward male gender and younger age as compared to those without adenoma. Conclusions: Subjects with acromegaly as compared to control have a higher prevalence of colonic polyps. There was no association of polyps seen with age, BMI, skin tags, homeostasis model assessment of insulin resistance index, duration of disease, and basal and glucose-suppressed GH and IGF-1 levels. There were no specific predictive factors detected. Screening full colonoscopy is recommended in all cases with acromegaly.

Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

Directory of Open Access Journals (Sweden)

Hyung Kwon Byeon

2015-01-01

Full Text Available Objective. Conventional surgical techniques of laryngomicrosurgery (LMS on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL, which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73, and there were 20 males and 19 females (17 professional voice users. In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps.

Dysphagia caused by a fibrovascular polyp: a case report.

NARCIS (Netherlands)

Blacha, M.M.; Sloots, C.E.J.; Munster, I.P. van; Wobbes, T.

2008-01-01

ABSTRACT: A 73-year old man presented with dysphagia for liquid and solid food. Barium contrast study of the esophagus and esophagoscopy demonstrated a fibrovascular polyp. This, almost 10 cm benign esophageal tumor, was removed surgically by a cervical esophagotomy. A fibrovascular polyp is a rare

Deep learning of contrast-coated serrated polyps for computer-aided detection in CT colonography

Science.gov (United States)

Näppi, Janne J.; Pickhardt, Perry; Kim, David H.; Hironaka, Toru; Yoshida, Hiroyuki

2017-03-01

Serrated polyps were previously believed to be benign lesions with no cancer potential. However, recent studies have revealed a novel molecular pathway where also serrated polyps can develop into colorectal cancer. CT colonography (CTC) can detect serrated polyps using the radiomic biomarker of contrast coating, but this requires expertise from the reader and current computer-aided detection (CADe) systems have not been designed to detect the contrast coating. The purpose of this study was to develop a novel CADe method that makes use of deep learning to detect serrated polyps based on their contrast-coating biomarker in CTC. In the method, volumetric shape-based features are used to detect polyp sites over soft-tissue and fecal-tagging surfaces of the colon. The detected sites are imaged using multi-angular 2D image patches. A deep convolutional neural network (DCNN) is used to review the image patches for the presence of polyps. The DCNN-based polyp-likelihood estimates are merged into an aggregate likelihood index where highest values indicate the presence of a polyp. For pilot evaluation, the proposed DCNN-CADe method was evaluated with a 10-fold cross-validation scheme using 101 colonoscopy-confirmed cases with 144 biopsy-confirmed serrated polyps from a CTC screening program, where the patients had been prepared for CTC with saline laxative and fecal tagging by barium and iodine-based diatrizoate. The average per-polyp sensitivity for serrated polyps >=6 mm in size was 93+/-7% at 0:8+/-1:8 false positives per patient on average. The detection accuracy was substantially higher that of a conventional CADe system. Our results indicate that serrated polyps can be detected automatically at high accuracy in CTC.

Syndromic Gastric Polyps : At the Crossroads of Genetic and Environmental Cancer Predisposition

NARCIS (Netherlands)

Brosens, Lodewijk A A; Giardiello, Francis M; Offerhaus, G Johan; Montgomery, Elizabeth A

2016-01-01

Gastric polyps occur in 1-4 % of patients undergoing gastroscopy. Although most are sporadic, some gastric polyps are part of an underlying hereditary syndrome. Gastric polyps can be seen in each of the well-known gastrointestinal polyposis syndromes, but also in Lynch syndrome and in several rare

Ultrafast Transient Absorption Spectroscopy of Polymer-Based Organophotoredox Catalysts Mimicking Transition-Metal Complexes

Science.gov (United States)

Jamhawi, Abdelqader; Paul, Anam C.; Smith, Justin D.; Handa, Sachin; Liu, Jinjun

2017-06-01

Transition-metal complexes of rare earth metals including ruthenium and iridium are most commonly employed as visible-light photocatalysts. Despite their highly important and broad applications, they have many disadvantages including high cost associated with low abundance in earth crust, potential toxicity, requirement of specialized ligands for desired activity, and difficulty in recycling of metal contents as well as associated ligands. Polymer-based organophotoredox catalysts are promising alternatives and possess unique advantages such as easier synthesis from inexpensive starting material, longer excited state life time, broad range of activity, sustainability, and recyclability. In this research talk, time-resolved photoluminescence and femtosecond transient absorption (TA) spectroscopy measurements of three novel polymer-based organophotoredox catalysts will be presented. By our synthetic team, their catalytic activity has been proven in some highly valuable chemical transformations, that otherwise require transition metal complexes. Time-resolved spectroscopic investigations have demonstrated that photoinduced processes in these catalysts are similar to the transition metal complexes. Especially, intramolecular vibrational relaxation, internal conversion, and intersystem crossing from the S1 state to the T1 state all occur on a sub-picosecond timescale. The long lifetime of the T1 state ( 2-3 microsecond) renders these polymers potent oxidizing and reducing agents. A spectroscopic and kinetic model has been developed for global fitting of TA spectra in both the frequency and time domains. Implication of the current ultrafast spectroscopy studies of these novel molecules to their roles in photocatalysis will be discussed.

Theoretical and Experimental Studies of New Polymer-Metal High-Dielectric Constant Nanocomposites

Science.gov (United States)

Ginzburg, Valeriy; Elwell, Michael; Myers, Kyle; Cieslinski, Robert; Malowinski, Sarah; Bernius, Mark

2006-03-01

High-dielectric-constant (high-K) gate materials are important for the needs of electronics industry. Most polymers have dielectric constant in the range 2 materials with K > 10 it is necessary to combine polymers with ceramic or metal nanoparticles. Several formulations based on functionalized Au-nanoparticles (R ˜ 5 -— 10 nm) and PMMA matrix polymer are prepared. Nanocomposite films are subsequently cast from solution. We study the morphology of those nanocomposites using theoretical (Self-Consistent Mean-Field Theory [SCMFT]) and experimental (Transmission Electron Microscopy [TEM]) techniques. Good qualitative agreement between theory and experiment is found. The study validates the utility of SCMFT as screening tool for the preparation of stable (or at least metastable) polymer/nanoparticle mixtures.

Polyp Removal of a Bloom Forming Jellyfish, Aurelia coerulea, in Korean Waters and Its Value Evaluation

Science.gov (United States)

Yoon, Wonduk; Chae, Jinho; Koh, Byoung-Seol; Han, Changhoon

2018-04-01

Aurelia coerulea is a bloom forming jellyfish that first appeared before 1980 in the western and southern Korean seas and which has been blamed for huge economical losses in all fields of marine activities. As a preventive measure to reduce economical losses, polyp removal was undertaken at Lake Shihwa, Lake Saemangeum, and Masan Bay, Korea. In the course of efforts during 2 years to remove polyps, polyps were surveyed, quantified, and removed. In these areas, the initial total polyp abundance was 5.04 × 109 and 46.25% of them were removed; Lake Shihwa the highest rates of removal and Lake Saemangeum the lowest. These efforts to remove polyps prevented the appearance of 1.20 × 109 medusae, corresponding to 78.28 × 106 kg. The cost of polyp removal was evaluated and compared with that of medusae removal. The ratio between the cost of polyp removal and that of medusae removal ranged between 0.78-3.14%, indicating large cost savings for polyp removal undertakings. However, the effect of polyp removal varied from positive to none, and we assumed that the cleared surface for polyp removal, quantity of removed polyp, and existence of polyps' hotspots in neighboring areas were the causes of the non-effectiveness of polyp removal undertakings.

Selective suppression of in situ proliferation of scyphozoan polyps by biofouling

International Nuclear Information System (INIS)

Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

2017-01-01

An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7–8 months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. - Highlights: • Biofouling selectively controls in situ proliferation of scyphozoan polyps • The contribution

The Effects of Size and Type of Vocal Fold Polyp on Some Acoustic Voice Parameters

Directory of Open Access Journals (Sweden)

Elaheh Akbari

2018-03-01

Full Text Available Background: Vocal abuse and misuse would result in vocal fold polyp. Certain features define the extent of vocal folds polyp effects on voice acoustic parameters. The present study aimed to define the effects of polyp size on acoustic voice parameters, and compare these parameters in hemorrhagic and non-hemorrhagic polyps. Methods: In the present retrospective study, 28 individuals with hemorrhagic or non-hemorrhagic polyps of the true vocal folds were recruited to investigate acoustic voice parameters of vowel/ æ/ computed by the Praat software. The data were analyzed using the SPSS software, version 17.0. According to the type and size of polyps, mean acoustic differences and correlations were analyzed by the statistical t test and Pearson correlation test, respectively; with significance level below 0.05. Results: The results indicated that jitter and the harmonics-to-noise ratio had a significant positive and negative correlation with the polyp size (P=0.01, respectively. In addition, both mentioned parameters were significantly different between the two types of the investigated polyps. Conclusion: Both the type and size of polyps have effects on acoustic voice characteristics. In the present study, a novel method to measure polyp size was introduced. Further confirmation of this method as a tool to compare polyp sizes requires additional investigations.

Localization by immunoperoxidase and estimation by radioimmunoassay of carcinoembryonic antigen on colonic polyp

International Nuclear Information System (INIS)

Sharkey, R.M.; Hagihara, P.F.; Goldenberg, D.M.

1977-01-01

A 3-layer immunoperoxidase technique was used to demonstrate carcinoembryonic antigen (CEA) in colonic polyps from patients with or without previous or concurrent malignancy. CEA was demonstrated in a higher percentage of the polyps received as fresh specimens that were rapidly frozen and fixed in ethanol, than in formalin-fixed, paraffin-embedded sections. Tissue CEA content of both colonic carcinomas and polyps was determined by radioimmunoassay, and it was found that benign colonic tumours had levels of tissue CEA comparable to colonic cancer, indicating that CEA concentration in a tumour does not reflect its grade of malignancy. In fact, in one case in which both colonic cancer and polyps were removed, the polyps has the higher quantities of tissue CEA. Further, tissue CEA concentration of a polyp was not dependent on its size or location. Studying the titres of circulating CEA in these patients revealed an elevation of plasma CEA in one-third of the patients with only colonic polyps, whilst the patients with cancer all had increased titres. (author)

Selective suppression of in situ proliferation of scyphozoan polyps by biofouling.

Science.gov (United States)

Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

2017-01-30

An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tridimensional ionic polymer metal composites: optimization of the manufacturing techniques

International Nuclear Information System (INIS)

Bonomo, C; Brunetto, P; Fortuna, L; Graziani, S; Bottino, M; Di Pasquale, G; Pollicino, A

2010-01-01

Ionic polymer metal composites (IPMCs) belong to electroactive polymers (EAPs) and have been suggested for various applications due to their light weight and to the fact that they react mechanically when stimulated by an electrical signal and vice versa. Thick IPMCs (3D-IPMCs) have been fabricated by hot pressing several Nafion ® 117 films. Additional post-processes (more cycles of Pt electroless plating and dispersing agents) have been applied to improve the 3D-IPMC performance. The electromechanical response of 3D-IPMCs has been examined by applying electrical signals and measuring the displacement and blocking force produced

Synthesis of Thin Film Composite Metal-Organic Frameworks Membranes on Polymer Supports

KAUST Repository

Barankova, Eva

2017-06-01

Since the discovery of size-selective metal-organic frameworks (MOF) researchers have tried to manufacture them into gas separation membranes. ZIF-8 became the most studied MOF for membrane applications mainly because of its simple synthesis, good chemical and thermal stability, recent commercial availability and attractive pore size. The aim of this work is to develop convenient methods for growing ZIF thin layers on polymer supports to obtain defect-free ZIF membranes with good gas separation properties. We present new approaches for ZIF membranes preparation on polymers. We introduce zinc oxide nanoparticles in the support as a secondary metal source for ZIF-8 growth. Initially the ZnO particles were incorporated into the polymer matrix and later on the surface of the polymer by magnetron sputtering. In both cases, the ZnO facilitated to create more nucleation opportunities and improved the ZIF-8 growth compared to the synthesis without using ZnO. By employing the secondary seeded growth method, we were able to obtain thin (900 nm) ZIF-8 layer with good gas separation performance. Next, we propose a metal-chelating polymer as a suitable support for growing ZIF layers. Defect-free ZIF-8 films with a thickness of 600 nm could be obtained by a contra-diffusion method. ZIF-8 membranes were tested for permeation of hydrogen and hydrocarbons, and one of the highest selectivities reported so far for hydrogen/propane, and propylene/propane was obtained. Another promising method to facilitate the growth of MOFs on polymeric supports is the chemical functionalization of the support surface with functional groups, which can complex metal ions and which can covalently bond the MOF crystals. We functionalized the surface of a common porous polymeric membrane with amine groups, which took part in the reaction to form ZIF-8 nanocrystals. We observed an enhancement in adhesion between the ZIF layer and the support. The effect of parameters of the contra-diffusion experiment

Improving Polyp Detection Algorithms for CT Colonography: Pareto Front Approach.

Science.gov (United States)

Huang, Adam; Li, Jiang; Summers, Ronald M; Petrick, Nicholas; Hara, Amy K

2010-03-21

We investigated a Pareto front approach to improving polyp detection algorithms for CT colonography (CTC). A dataset of 56 CTC colon surfaces with 87 proven positive detections of 53 polyps sized 4 to 60 mm was used to evaluate the performance of a one-step and a two-step curvature-based region growing algorithm. The algorithmic performance was statistically evaluated and compared based on the Pareto optimal solutions from 20 experiments by evolutionary algorithms. The false positive rate was lower (pPareto optimization process can effectively help in fine-tuning and redesigning polyp detection algorithms.

Demonstration of Thermally Sprayed Metal and Polymer Coatings for Steel Structures at Fort Bragg, NC

Science.gov (United States)

2017-09-01

ER D C/ CE RL T R- 17 -3 0 DoD Corrosion Prevention and Control Program Demonstration of Thermally Sprayed Metal and Polymer Coatings...and Polymer Coatings for Steel Structures at Fort Bragg, NC Final Report on Project F07-AR10 Larry D. Stephenson, Alfred D. Beitelman, Richard G...5 2.1.2 Thermoplastic polymer coating (flame spray

Polymer-Derived In- Situ Metal Matrix Composites Created by Direct Injection of a Liquid Polymer into Molten Magnesium

Science.gov (United States)

Sudarshan; Terauds, Kalvis; Anilchandra, A. R.; Raj, Rishi

2014-02-01

We show that a liquid organic precursor can be injected directly into molten magnesium to produce nanoscale ceramic dispersions within the melt. The castings made in this way possess good resistance to tensile deformation at 673 K (400 °C), confirming the non-coarsening nature of these dispersions. Direct liquid injection into molten metals is a significant step toward inserting different chemistries of liquid precursors to generate a variety of polymer-derived metal matrix composites.

Reaction factors for photo-electrochemical deposition of metal silver on polypyrrole as conducting polymer

International Nuclear Information System (INIS)

Kawakita, Jin; Boter, Jelmer M.; Shova, Neupane; Fujihira, Hiroshi; Chikyow, Toyohiro

2015-01-01

Composite of metal and conducting polymer is expected for electrical application by the use of their advantages. For improvement of the composite’s characteristics, it is important to control formation rate and structure of the composites obtained by simultaneous metal deposition and polymerization under photo irradiation. The purpose of this research was to reveal the effects of UV irradiation and dopant type for conducting polymer on photo-electrochemical deposition of metal. Cathodic polarization curves for silver deposition on polypyrrole doped with different types of anion at different intensity of the UV light were compared. Deposited particles were evaluated by the statistical analysis. The experimental results showed that silver deposition on polypyrrole was enhanced by UV introduction and depended on the dopant type.

Structural characterisation of 1- and 2-dimensional transition metal polymers using powder neutron diffraction

International Nuclear Information System (INIS)

James, M.

1999-01-01

Powder neutron diffraction provides an alternate technique for the structural study of transition metal polymers and finds utility over standard X-ray methods in two significant ways. Firstly, due to a different instrument geometry, preferred orientation effects are removed from the system. The second advantage gained by utilising neutrons is that H atoms in the sample contribute much more to the nuclear scattering of the diffraction profile - allowing their atomic position to be accurately determined. In X-ray diffraction studies, where H atoms typically account for only ∼3-5% of the scattering from the sample, it is essentially impossible to refine their position in the molecular structure. The structures of several transition metal polymers have been determined using neutrons from the HIFAR reactor at ANSTO and the Powder Diffractometers HRPD and MRPD, along with Rietveld refinement methods. The 1-dimensional polymer dibromobis(thiazole)nickel(II) illustrated in the paper is characteristic of these types of systems which are comprised of transition metal centres bridged by halogen atoms with pendant amine side groups

Giant fibrovascular polyp of the esophagus: a case report

International Nuclear Information System (INIS)

Ryoo, Jae Wook; Kim, Jeung Sook; Lee, Kyung Soo; Lim, Jae Hoon; Shim, Young Mog; Han, Joung Ho

1995-01-01

Fibrovascular polyp of the esophagus is a rare and benign pedunculated intraluminal tumor. The tumor consists of varying amount of vascular fibrous and adipose tissue that arises in the submucosa and is covered by squamous epithelium. We report the typical radiographic, CT and MR findings of a case of giant fibrovascular polyp of the esophagus

Increased Prevalence of Colorectal Polyp in Acromegaly Patients: A Case-Control Study

Directory of Open Access Journals (Sweden)

Ali Riza Koksal

2014-01-01

Full Text Available An increase in the prevalence of colorectal polyps and cancer is reported in patients with acromegaly. This trial is designed to determine whether there is an increase in the prevalence of colorectal polyps/cancer in Turkish acromegaly patients. Sixty-six patients, who were under follow-up with the diagnosis of acromegaly and underwent total colonoscopic examination, were enrolled in the study. Sixty-five age- and gender-matched patients with nonspecific complaints were selected as control. The mean age of acromegalic patients was 51.5±12.8 years of whom 27 (40.9% were females. In 20 (30.3% of the patients with acromegaly a total of 65 colorectal polyps were detected. Forty-seven (72.3% of the polyps were detected at the rectosigmoid region. In 8 (12.3% of the 65 control patients a total of 17 polyps were found. There was a statistically significant difference between the groups (P=0.018. At the logistic regression analysis we found that the risk for colon polyps increased 3.2-fold in the presence of acromegaly, irrespective of age and gender (OR: 3.191, 95% CI: 1.25–8.13. In conclusion, patients who were followed up with the diagnosis of acromegaly should be taken to the colonoscopic surveillance program and all polyps detected should be excised in order to protect them from colorectal cancer.

Measurement of smaller colon polyp in CT colonography images using morphological image processing.

Science.gov (United States)

Manjunath, K N; Siddalingaswamy, P C; Prabhu, G K

2017-11-01

Automated measurement of the size and shape of colon polyps is one of the challenges in Computed tomography colonography (CTC). The objective of this retrospective study was to improve the sensitivity and specificity of smaller polyp measurement in CTC using image processing techniques. A domain knowledge-based method has been implemented with hybrid method of colon segmentation, morphological image processing operators for detecting the colonic structures, and the decision-making system for delineating the smaller polyp-based on a priori knowledge. The method was applied on 45 CTC dataset. The key finding was that the smaller polyps were accurately measured. In addition to 6-9 mm range, polyps of even processing. It takes [Formula: see text] min for measuring the smaller polyp in a dataset of 500 CTC images. With this method, [Formula: see text] and [Formula: see text] were achieved. The domain-based approach with morphological image processing has given good results. The smaller polyps were measured accurately which helps in making right clinical decisions. Qualitatively and quantitatively the results were acceptable when compared to the ground truth at [Formula: see text].

Real-time detection of metal ions using conjugated polymer composite papers.

Science.gov (United States)

Lee, Ji Eun; Shim, Hyeon Woo; Kwon, Oh Seok; Huh, Yang-Il; Yoon, Hyeonseok

2014-09-21

Cellulose, a natural polymeric material, has widespread technical applications because of its inherent structural rigidity and high surface area. As a conjugated polymer, polypyrrole shows practical potential for a diverse and promising range of future technologies. Here, we demonstrate a strategy for the real-time detection and removal of metal ions with polypyrrole/cellulose (PPCL) composite papers in solution. Simply, the conjugated polymer papers had different chemical/physical properties by applying different potentials to them, which resulted in differentiable response patterns and adsorption efficiencies for individual metal ions. First, large-area PPCL papers with a diameter of 5 cm were readily obtained via vapor deposition polymerization. The papers exhibited both mechanical flexibility and robustness, in which polypyrrole retained its redox property perfectly. The ability of the PPCL papers to recognize metal ions was examined in static and flow cells, in which real-time current change was monitored at five different applied potentials (+1, +0.5, 0, -0.5, and -1 V vs. Ag/AgCl). Distinguishable signals in the PPCL paper responses were observed for individual metal ions through principal component analysis. Particularly, the PPCL papers yielded unique signatures for three metal ions, Hg(ii), Ag(i), and Cr(iii), even in a real sample, groundwater. The sorption of metal ions by PPCL papers was examined in the flow system. The PPCL papers had a greatly superior adsorption efficiency for Hg(ii) compared to that of the other metal ions. With the strong demand for the development of inexpensive, flexible, light-weight, and environmentally friendly devices, the fascinating characteristics of these PPCL papers are likely to provide good opportunities for low-cost paper-based flexible or wearable devices.

Glycoprotein expression by adenomatous polyps of the colon

Science.gov (United States)

Roney, Celeste A.; Xie, Jianwu; Xu, Biying; Jabour, Paul; Griffiths, Gary; Summers, Ronald M.

2008-03-01

Colon cancer is the second leading cause of cancer related deaths in the United States. Specificity in diagnostic imaging for detecting colorectal adenomas, which have a propensity towards malignancy, is desired. Adenomatous polyp specimens of the colon were obtained from the mouse model of colorectal cancer called adenomatous polyposis coli-multiple intestinal neoplasia (APC Min). Histological evaluation, by the legume protein Ulex europaeus agglutinin I (UEA-1), determined expression of the glycoprotein α-L-fucose. FITC-labelled UEA-1 confirmed overexpression of the glycoprotein by the polyps on fluorescence microscopy in 17/17 cases, of which 13/17 included paraffin-fixed mouse polyp specimens. In addition, FITC-UEA-1 ex vivo multispectral optical imaging of 4/17 colonic specimens displayed over-expression of the glycoprotein by the polyps, as compared to non-neoplastic mucosa. Here, we report the surface expression of α-L-fucosyl terminal residues by neoplastic mucosal cells of APC specimens of the mouse. Glycoprotein expression was validated by the carbohydrate binding protein UEA-1. Future applications of this method are the development of agents used to diagnose cancers by biomedical imaging modalities, including computed tomographic colonography (CTC). UEA-1 targeting to colonic adenomas may provide a new avenue for the diagnosis of colorectal carcinoma by CT imaging.

Charge Transport in Carbon Nanotubes-Polymer Composite Photovoltaic Cells

Science.gov (United States)

Ltaief, Adnen; Bouazizi, Abdelaziz; Davenas, Joel

2009-01-01

We investigate the dark and illuminated current density-voltage (J/V) characteristics of poly(2-methoxy-5-(2’-ethylhexyloxy)1-4-phenylenevinylene) (MEH-PPV)/single-walled carbon nanotubes (SWNTs) composite photovoltaic cells. Using an exponential band tail model, the conduction mechanism has been analysed for polymer only devices and composite devices, in terms of space charge limited current (SCLC) conduction mechanism, where we determine the power parameters and the threshold voltages. Elaborated devices for MEH-PPV:SWNTs (1:1) composites showed a photoresponse with an open-circuit voltage Voc of 0.4 V, a short-circuit current density JSC of 1 µA/cm² and a fill factor FF of 43%. We have modelised the organic photovoltaic devices with an equivalent circuit, where we calculated the series and shunt resistances.

Fused filament 3D printing of ionic polymer-metal composites (IPMCs)

International Nuclear Information System (INIS)

Carrico, James D; Traeden, Nicklaus W; Leang, Kam K; Aureli, Matteo

2015-01-01

This paper describes a new three-dimensional (3D) fused filament additive manufacturing (AM) technique in which electroactive polymer filament material is used to build soft active 3D structures, layer by layer. Specifically, the unique actuation and sensing properties of ionic polymer-metal composites (IPMCs) are exploited in 3D printing to create electroactive polymer structures for application in soft robotics and bio-inspired systems. The process begins with extruding a precursor material (non-acid Nafion precursor resin) into a thermoplastic filament for 3D printing. The filament is then used by a custom-designed 3D printer to manufacture the desired soft polymer structures, layer by layer. Since at this stage the 3D-printed samples are not yet electroactive, a chemical functionalization process follows, consisting in hydrolyzing the precursor samples in an aqueous solution of potassium hydroxide and dimethyl sulfoxide. Upon functionalization, metal electrodes are applied on the samples through an electroless plating process, which enables the 3D-printed IPMC structures to be controlled by voltage signals for actuation (or to act as sensors). This innovative AM process is described in detail and the performance of 3D printed IPMC actuators is compared to an IPMC actuator fabricated from commercially available Nafion sheet material. The experimental results show comparable performance between the two types of actuators, demonstrating the potential and feasibility of creating functional 3D-printed IPMCs. (paper)

Fused filament 3D printing of ionic polymer-metal composites (IPMCs)

Science.gov (United States)

Carrico, James D.; Traeden, Nicklaus W.; Aureli, Matteo; Leang, Kam K.

2015-12-01

This paper describes a new three-dimensional (3D) fused filament additive manufacturing (AM) technique in which electroactive polymer filament material is used to build soft active 3D structures, layer by layer. Specifically, the unique actuation and sensing properties of ionic polymer-metal composites (IPMCs) are exploited in 3D printing to create electroactive polymer structures for application in soft robotics and bio-inspired systems. The process begins with extruding a precursor material (non-acid Nafion precursor resin) into a thermoplastic filament for 3D printing. The filament is then used by a custom-designed 3D printer to manufacture the desired soft polymer structures, layer by layer. Since at this stage the 3D-printed samples are not yet electroactive, a chemical functionalization process follows, consisting in hydrolyzing the precursor samples in an aqueous solution of potassium hydroxide and dimethyl sulfoxide. Upon functionalization, metal electrodes are applied on the samples through an electroless plating process, which enables the 3D-printed IPMC structures to be controlled by voltage signals for actuation (or to act as sensors). This innovative AM process is described in detail and the performance of 3D printed IPMC actuators is compared to an IPMC actuator fabricated from commercially available Nafion sheet material. The experimental results show comparable performance between the two types of actuators, demonstrating the potential and feasibility of creating functional 3D-printed IPMCs.

Further refinements of the polyp snare for interuterine surgery--a new modality for treatment of myomas and polyps.

Science.gov (United States)

McLucas, B

1995-01-01

Hysteroscopic treatment of 30 patients suffering from menorrhagia or post-partum complications was accomplished using an electrosurgical polyp snare. Using this method, 18 polyps and 12 myomas were successfully removed in less than twenty minutes without complications. Local anaesthesia was used in 12 patients. Three patients have presented with recurrence of menorrhagia, with a minimum of six months follow-up. Benefits of this technique compared to uterine resectoscopy include shorter operative time, decreased risk of fluid overload, and less risk of uterine perforation. The snare is difficult to use and a learning curve exists. Higher currents than that used for resection are required.

Thin HTSC films produced by a polymer metal precursor technique

Science.gov (United States)

Lampe, L. v.; Zygalsky, F.; Hinrichsen, G.

In precursors the metal ions are combined with acid groups of polymethacrylic acid (PMAA), polyacrylic acid (PAA) or novolac. Compared to thermal degradation temperature of pure polymers those of precursors are low. Precursors films were patterned by UV lithography. Diffractometric investigations showed that the c-axis oriented epitaxial films of YBa 2Cu 3O x and Bi 2Sr 2CaCu 2O x originated from amorphous metal oxide films, which were received after thermal degradation of the precursor. Transition temperatures and current densities were determined by electric resistivity measurements.

Metal oxide targets produced by the polymer-assisted deposition method

Energy Technology Data Exchange (ETDEWEB)

Garcia, Mitch A., E-mail: mitch@berkeley.ed [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, T. [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ashby, Paul D. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gates, Jacklyn M. [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Stavsetra, Liv [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gregorich, Kenneth E.; Nitsche, Heino [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2010-02-11

The polymer-assisted deposition (PAD) method was used to create crack-free homogenous metal oxide films for use as targets in nuclear science applications. Metal oxide films of europium, thulium, and hafnium were prepared as models for actinide oxides. Films produced by a single application of PAD were homogenous and uniform and ranged in thickness from 30 to 320 nm. Reapplication of the PAD method (six times) with a 10% by weight hafnium(IV) solution resulted in an equally homogeneous and uniform film with a total thickness of 600 nm.

Metal oxide targets produced by the polymer-assisted deposition method

International Nuclear Information System (INIS)

Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, T.; Ashby, Paul D.; Gates, Jacklyn M.; Stavsetra, Liv; Gregorich, Kenneth E.; Nitsche, Heino

2010-01-01

The polymer-assisted deposition (PAD) method was used to create crack-free homogenous metal oxide films for use as targets in nuclear science applications. Metal oxide films of europium, thulium, and hafnium were prepared as models for actinide oxides. Films produced by a single application of PAD were homogenous and uniform and ranged in thickness from 30 to 320 nm. Reapplication of the PAD method (six times) with a 10% by weight hafnium(IV) solution resulted in an equally homogeneous and uniform film with a total thickness of 600 nm.

Nanostructured Block Polymer Membranes as High Capacity Adsorbers for the Capture of Metal Ions from Water

Science.gov (United States)

Boudouris, Bryan; Weidman, Jacob; Mulvenna, Ryan; Phillip, William

The efficient removal of metal ions from aqueous streams is of significant import in applications ranging from industrial waste treatment to the purification of drinking water. An emerging paradigm associated with this separation is one that utilizes membrane adsorbers as a means by which to bind metal salt contaminants. Here, we demonstrate that the casting of an A-B-C triblock polymer using the self-assembly and non-solvent induced phase separation (SNIPS) methodology results in a nanoporous membrane geometry. The nature of the triblock polymer affords an extremely high density of binding sites within the membrane. As such, we demonstrate that the membranes with binding capacities equal to that of state-of-the-art packed bed columns. Moreover, because the affinity of the C moiety can be tuned, highly selective binding events can occur based solely on the chemistry of the block polymer and the metal ions in solution (i.e., in a manner that is independent of the size of the metal ions). Due to these combined facts, these membranes efficiently remove heavy metal (e.g., lead- and cadmium-based) salts from contaminated water streams with greater than 95% efficiency. Finally, we show that the membranes can be regenerated through a simple treatment in order to provide long-lasting adsorber systems as well. Thus, it is anticipated that these nanostructured triblock polymer membranes are a platform by which to obtain next-generation water purification processes.

A Giant Pedunculated Urothelial Polyp Mimicking Bladder Mass in a Child: A Rare Case

Directory of Open Access Journals (Sweden)

Mehmet Kaba

2014-01-01

Full Text Available Ureteral fibroepithelial polyps are rarely seen benign tumors with mesodermal origin. These polyps can involve kidney, pelvis, ureter, bladder, and urethra. The most common symptoms are hematuria and flank pain. The choice of treatment is either endoscopic or surgical resection of polyp by sparing kidney. Here, we presented a pediatric case with giant, fibroepithelial polyp that mimics bladder tumor, originating from middle segment of the ureter.

Male and female stem cells and sex reversal in Hydra polyps

OpenAIRE

Bosch, Thomas C. G.; David, Charles N.

1986-01-01

Single interstitial stem cells of male polyps of Hydra magnipapillata give rise to clones that differentiate either male or female gametes. To test the sexual stability of these clones, stem cells were recloned. The results indicate that stem cells from female clones are stable in their sexual differentiation capacity; male stem cells, by comparison, switch sexual phenotype at the rate of 10-2 per cell per generation. As a result, female polyps contain only female stem cells; male polyps cont...

Photoinduced charge and energy transfer in dye-doped conjugated polymers

International Nuclear Information System (INIS)

Veldman, Dirk; Bastiaansen, Jolanda J.A.M.; Langeveld-Voss, Bea M.W.; Sweelssen, Joergen; Koetse, Marc M.; Meskers, Stefan C.J.; Janssen, Rene A.J.

2006-01-01

Conjugated polymer-molecular dye blends of MDMO-PPV (poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene]) and PF1CVTP (poly[9,9-dioctylfluorene-2,7-diyl-alt-2,5-bis(2-thienyl-1-cyanovinyl) -1-(3',7= '-dimethyloctyloxy)-4-methoxybenzene-5'',5''-diyl]) with three dipyrrometheneboron difluoride (bodipy) dyes were studied by (time-resolved) fluorescence and photoinduced absorption spectroscopy to determine quantitatively the relation between the electronic HOMO and LUMO levels and the occurrence of energy or charge transfer after optical excitation. We find that for MDMO-PPV photoinduced charge transfer to the dyes occurs, while photoexcitation of PF1CVTP exclusively results in energy transfer. The differences can be rationalized by assuming that the energy of the charge separated state is 0.33-0.45 eV higher than the energy determined from oxidation and reduction potentials of donor and acceptor, respectively. This provides an important design rule to identify appropriate materials for polymer solar cells that can have a high open-circuit voltage

Application of hybrid organic/inorganic polymers as coatings on metallic substrates

Science.gov (United States)

Augustinho, T. R.; Motz, G.; Ihlow, S.; Machado, R. A. F.

2016-09-01

Acrylic polymers, particularly poly (methyl methacrylate) (PMMA), have certain specific properties, such as good film formation, transparency, and good mechanical properties, which have been widely used in paints, coatings and adhesives. However, the limited chemical and physical stability of these pure polymers limits their applications when exposed to hostile conditions, as in ship hulls, for example. A suitable way to enhance PMMA properties is the addition of silicon polymers with very good protective characteristics. In this study, a PMMA and HTT 1800 (commercial silazane) copolymer were applied on metallic substrate and compared to pure PMMA and HTT 1800. All the materials were applied as coatings. They were applied on stainless steel via dip-coating to investigate the coating properties. Thermal cycling was employed to analyze coating durability at high temperatures (50 °C to 600 °C). Optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the coated surfaces, and the adhesion of pure PMMA, pure HTT 1800 and PMMA/HTT 1800 coatings on metallic substrate was investigated by Cross-Cut-Test (ASTM D 3359). The sessile drop method was used to determine the contact angle. PMMA coatings presented complete degradation from 250 °C, while hybrid coatings of PMMA and HTT 1800 have good protection until 400 °C. The adherence of the coating on metallic substrate showed improvement in all synthesized materials when compared to pure PMMA, obtaining the best adherence possible. The contact angle test showed that the hydrophobicity of the hybrid coatings is higher than that of the pure coatings.

Coupling Metallic Nanostructures to Thermally Responsive Polymers Allows the Development of Intelligent Responsive Membranes

Directory of Open Access Journals (Sweden)

J. Rubén Morones-Ramírez

2014-01-01

Full Text Available Development of porous membranes capable of controlling flow or changing their permeability to specific chemical entities, in response to small changes in environmental stimuli, is an area of appealing research, since these membranes present a wide variety of applications. The synthesis of these membranes has been mainly approached through grafting of environmentally responsive polymers to the surface walls of polymeric porous membranes. This synergizes the chemical stability and mechanical strength of the polymer membrane with the fast response times of the bonded polymer chains. Therefore, different composite membranes capable of changing their effective pore size with environmental triggers have been developed. A recent interest has been the development of porous membranes responsive to light, since these can achieve rapid, remote, noninvasive, and localized flow control. This work describes the synthesis pathway to construct intelligent optothermally responsive membranes. The method followed involved the grafting of optothermally responsive polymer-metal nanoparticle nanocomposites to polycarbonate track-etched porous membranes (PCTEPMs. The nanoparticles coupled to the polymer grafts serve as the optothermal energy converters to achieve optical switching of the pores. The results of the paper show that grafting of the polymer and in situ synthesis of the metallic particles can be easily achieved. In addition, the composite membranes allow fast and reversible switching of the pores using both light and heat permitting control of fluid flow.

Giant fibrovascular esophageal polyp misdiagnosed as achalasia.

Science.gov (United States)

Cordoş, I; Istrate, A; Codreşi, M; Bolca, C

2012-01-01

A 59 years old woman was admitted in our unit accusing longtime dysphagia and regurgitation. On admission, the patient was wearing a 3 month old definitive feeding gastrostomy tube. The contrast swallow, endoscopy and esophageal manometry established the diagnostic--achalasia. We removed the gastrostomy tube and we performed an open Heller myotomy. The postoperative period was uneventful and the patient was discharged one week later with affirmatively unimpaired deglutition. One month later, the patient was admitted via emergency with a giant fibrous tumor arising from her mouth after an episode of strong coughing and vomiting. The repeated endoscopy showed a giant esophageal polyp that was missed by the previous investigations, originating from pharingoesophageal junction. The esophageal polyp was resected by cervical approach with good postoperative outcome. The polyp's particular extreme dimensions (27 cm) prevented the acute asphyxia by blockage at the laryngeal level, possibly provoked by smaller tumors. As postoperative one month barium swallow showed a normal esophageal aspect, a final question remains--was achalasia real or an erroneous diagnosis was established the second time too?

Clinical Significance of Colonoscopy in Patients with Upper Gastrointestinal Polyps and Neoplasms: A Meta-Analysis

Science.gov (United States)

Wu, Zhen-Jie; Lin, Yuan; Xiao, Jun; Wu, Liu-Cheng; Liu, Jun-Gang

2014-01-01

Background Some authors have studied the relationship between the presence of polyps, adenomas and cancers of upper gastrointestinal tract (stomach and duodenum) and risk of colorectal polyps and neoplasms; however, the results are controversial, which may be due to study sample size, populations, design, clinical features, and so on. No meta-analysis, which can be generalized to a larger population and could provide a quantitative pooled risk estimate of the relationship, of this issue existed so far. Methods We performed a meta-analysis to evaluate risk of colorectal polyps or neoplasms in patients with polyps, adenomas or cancers in upper gastrointestinal tract comparing with controls. A search was conducted through PubMed, EMBASE, reference lists of potentially relevant papers, and practice guidelines up to 27 November 2013 without languages restriction. Odd ratios (ORs) were pooled using random-effects models. Results The search yielded 3 prospective and 21 retrospective case-control studies (n = 37152 participants). The principal findings included: (1) OR for colorectal polyps was 1.15 (95% CI, 1.04–1.26) in the gastric polyps group comparing with control groups; (2) Patients with gastric polyps and neoplasms have higher risk (OR, 1.31 [95% CI, 1.06–1.62], and 1.72 [95% CI, 1.42–2.09], respectively) of colorectal neoplasms comparing with their controls; and (3) Positive association was found between the presence of colorectal neoplasms and sporadic duodenal neoplasms (OR, 2.59; 95% CI, 1.64–4.11). Conclusions Findings from present meta-analysis of 24 case-control studies suggest that the prevalence of colorectal polyps was higher in patients with gastric polyps than in those without gastric polyps, and the risk of colorectal neoplasms increases significantly in patients with gastric polyps, neoplasms, and duodenal neoplasms. Therefore, screening colonoscopy should be considered for patients with upper gastrointestinal polyps and neoplasms. PMID

Sulfur polymer cement encapsulation of RCRA toxic metals and metal oxides

International Nuclear Information System (INIS)

Calhoun, C.L. Jr.; Nulf, L.E.; Gorin, A.H.

1995-06-01

A study was conducted to determine the suitability of Sulfur Polymer Cement (SPC) encapsulation technology for the stabilization of RCRA toxic metal and metal oxide wastes. In a series of bench-scale experiments, the effects of sodium sulfide additions to the waste mixture, residence time, and temperature profile were evaluated. In addition, an effort was made to ascertain the degree to which SPC affords chemical stabilization as opposed to physical encapsulation. Experimental results have demonstrated that at the 25 wt % loading level, SPC can effectively immobilize Cr, Cr 2 O 3 , Hg, Pb, and Se to levels below regulatory limits. SPC encapsulation also has been shown to significantly reduce the leachability of other toxic compounds including PbO, PbO 2 , As 2 O 3 , BaO, and CdO. In addition, data has confirmed sulfide conversion of Hg, Pb, PbO, PbO 2 , and BaO as the product of their reaction with SPC

Detection of helicobacter pylori in nasal polyps using rapid urease test and ELISA

Directory of Open Access Journals (Sweden)

Masood Kaviani

2009-01-01

Full Text Available Introduction: Nasal polyposis is an inflammatory condition of unknown etiology. Recently concerns regarding gastroesophageal reflux or helicobacter pylori as a possible pathologic cause of nasal polyps have been increasing. The present study was planned to investigate the presence of helicobacter pylori in nasal polyps. Materials and Methods: This case-control study was undertaken enrolling 37 patients with nasal polyps who had undergone nasal endoscopic sinus surgery and 38 control subjects. Biopsy specimens of nasal polyps and inferior turbinates were assessed by rapid urease test. Blood samples of both study and control subjects were evaluated for anti H.pylori IgG by ELISA. H. pylori status was regarded positive, if both tests were positive. Results: Seropositivity was more common in the patients with nasal polyps (66.2% than control subjects (36.8% (P

Associations between dietary fiber and colorectal polyp risk differ by polyp type and smoking status.

Science.gov (United States)

Fu, Zhenming; Shrubsole, Martha J; Smalley, Walter E; Ness, Reid M; Zheng, Wei

2014-05-01

The association of dietary fiber intake with colorectal cancer risk is established. However, the association may differ between cigarette smokers and nonsmokers. We evaluated this hypothesis in a large colonoscopy-based case-control study. Dietary fiber intakes were estimated by self-administered food frequency questionnaire. Unconditional logistic regression analysis was used to estimate ORs and 95% CIs with adjustment for potential confounders. Analysis also was stratified by cigarette smoking and sex. High dietary fiber intake was associated with reduced risk of colorectal polyps (P-trend = 0.003). This association was found to be stronger among cigarette smokers (P-trend = 0.006) than nonsmokers (P-trend = 0.21), although the test for multiplicative interaction was not statistically significant (P = 0.11). This pattern of association was more evident for high-risk adenomatous polyps (ADs), defined as advanced or multiple ADs (P-interaction smoking and dietary fiber intake = 0.09). Among cigarette smokers who smoked ≥23 y, a 38% reduced risk of high-risk ADs was found to be associated with high intake of dietary fiber compared with those in the lowest quartile fiber intake group (P-trend = 0.004). No inverse association with dietary fiber intake was observed for low-risk ADs, defined as single nonadvanced ADs. Cigarette smoking may modify the association of dietary fiber intake with the risk of colorectal polyps, especially high-risk ADs, a well-established precursor of colorectal cancer.

Fibroepithelial ureteral polyps presenting as ureteropelvic obstruction

Science.gov (United States)

Cusano, Antonio; Abarzua-Cabezas, Fernando; Kesler, Stuart

2014-01-01

A 57-year-old woman presented with bilateral abdominal pain and flank discomfort. Imaging studies, consisting of CT scan, diethylene triamine pentaacetic acid renal scan with Lasix and a retrograde pyelogram, indicated an obstruction at the uteropelvic junction (UPJ), possibly due to fibroepithelial polyps within the ureter. A robotic pyeloplasty revealed a ureteral diverticulum and a thin, still-attached fibroepithelial polyp of approximately 2 cm in length. The patient tolerated the procedure well and was discharged one day postpyeloplasty with no reported complications. This rare clinical scenario should be considered when formulating a diagnosis for a UPJ obstruction. PMID:24759168

Predictors of Colorectal Polyp Recurrence after the First Polypectomy in Private Practice Settings: A Cohort Study

Science.gov (United States)

Viel, Jean-François; Studer, Jean-Marie; Ottignon, Yves; Hirsch, Jean-Pierre

2012-01-01

Background Supplementary observational data in the community setting are required to better assess the predictors of colorectal polyp recurrence and the effectiveness of colonoscopy surveillance under real circumstances. Aim The goal of this study was to identify patient characteristics and polyp features at baseline colonoscopy that are associated with the recurrence of colorectal polyps (including hyperplastic polyps) among patients consulting private practice physicians. Patients and Methods This cohort study was conducted from March 2004 to December 2010 in 26 private gastroenterology practices (France). It included 1023 patients with a first-time diagnosis of histologically confirmed polyp removed during a diagnostic or screening colonoscopy. At enrollment, interviews were conducted to obtain data on socio-demographic variables and risk factors. Pathology reports were reviewed to abstract data on polyp features at baseline colonoscopy. Colorectal polyps diagnosed at the surveillance colonoscopy were considered as end points. The time to event was analyzed with an accelerated failure time model assuming a Weibull distribution. Results Among the 1023 patients with colorectal polyp at baseline, 553 underwent a surveillance colonoscopy. The mean time interval from baseline colonoscopy to first surveillance examination was 3.42 (standard deviation, 1.45) years. The recurrence rates were 50.5% and 32.9% for all polyps and adenomas, respectively. In multivariate models, the number of polyps at baseline was the only significant predictor for both polyp recurrence (hazard ratio [HR] 1.19, 95% CI 1.06 to 1.33), and adenoma recurrence (HR 1.17, 95% CI 1.03 to 1.34). Conclusion The efficacy of surveillance colonoscopy in community gastroenterology practice compared favorably with academic settings. This study provides further evidence that the number of initial colorectal polyps is useful for predicting the risk of polyp recurrence, even in the community setting. PMID

Charge and energy dynamics in photo-excited poly(para-phenylenevinylene) systems

International Nuclear Information System (INIS)

Gisslen, L.; Johansson, A.; Stafstroem, S.

2004-01-01

We report results from simulations of charge and energy dynamics in poly(para-phenylenevinylene) (PPV) and PPV interacting with C 60 . The simulations were performed by solving the time-dependent Schroedinger equation and the lattice equation of motion simultaneously and nonadiabatically. The electronic system and the coupling of the electrons to the lattice were described by an extended three-dimensional version of the Su-Schrieffer-Heeger model, which also included an external electric field. Electron and lattice dynamics following electronic excitations at different energies have been simulated. The effect of additional lattice energy was also included in the simulations. Our results show that both exciton diffusion and transitions from high to lower lying excitations are stimulated by increasing the lattice energy. Also field induced charge separation occurs faster if the lattice energy is increased. This separation process is highly nonadiabatic and involves a significant rearrangement of the electron distribution. In the case of PPV coupled to C 60 , we observe a spontaneous charge separation. The separation time is in this case limited by the local concentration of C 60 molecules close to the PPV chain

Prevalence of colon polyps detected by colonoscopy screening in asymptomatic black and white patients

Science.gov (United States)

Lieberman, David; Holub, Jennifer; Moravec, Matthew; Eisen, Glenn; Peters, Dawn; Morris, Cynthia

2013-01-01

Context Compared to whites, Black men and women have a higher incidence and mortality from colorectal cancer and may develop cancer at a younger age. Colorectal cancer screening might be less effective in Blacks, if there are racial differences in the age-adjusted prevalence and location of cancer precursor lesions. Objectives To determine and compare the prevalence rates and location of polyp(s) >9mm in asymptomatic Blacks and whites who receive colonoscopy screening. Design, Setting, and Patients Colonoscopy data were prospectively collected from 67 practice sites in the United States using a computerized endoscopic report generator from 2004–2005. Data were transmitted to a central data repository, where all asymptomatic whites (n = 80,061) and Blacks (n = 5464) who received screening colonoscopy were identified. Main outcome measures Prevalence and location of polyp(s) >9mm, adjusted for age, gender, and family history of colorectal cancer in a multivariate analysis. Results Both Black men and women had a higher prevalence of polyp(s) >9mm (7.7 versus 6.2%; p 9mm (OR 1.133; 95% CI 0.93,1.38). However, in a sub-analysis of patients over age 60 years, proximal polyps >9mm were more likely in Black men (p = 0.026) and women (p9mm, and Black over age 60 years are more likely to proximal polyps >9mm. PMID:18812532

Polymer-assisted metal deposition (PAMD): a full-solution strategy for flexible, stretchable, compressible, and wearable metal conductors.

Science.gov (United States)

Yu, You; Yan, Casey; Zheng, Zijian

2014-08-20

Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlling Film Morphology in Conjugated Polymer

Science.gov (United States)

Park, Lee Y.; Munro, Andrea M.; Ginger, David S.

2009-01-01

We study the effects of patterned surface chemistry on the microscale and nanoscale morphology of solution-processed donor/acceptor polymer-blend films. Focusing on combinations of interest in polymer solar cells, we demonstrate that patterned surface chemistry can be used to tailor the film morphology of blends of semiconducting polymers such as poly-[2-(3,7-dimethyloctyloxy)-5-methoxy-p-phenylenevinylene] (MDMO-PPV), poly-3-hexylthiophene (P3HT), poly[(9,9-dioctylflorenyl-2,7-diyl)-co-benzothiadiazole)] (F8BT), and poly(9,9-dioctylfluorene-co-bis-N,N’-(4-butylphenyl)-bis-N,N’-phenyl-1,4-phenylendiamine) (PFB) with the fullerene derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We present a method for generating patterned, fullerene-terminated monolayers on gold surfaces, and use microcontact printing and Dip-Pen Nanolithography (DPN) to pattern alkanethiols with both micro- and nanoscale features. After patterning with fullerenes and other functional groups, we backfill the rest of the surface with a variety of thiols to prepare substrates with periodic variations in surface chemistry. Spin coating polymer:PCBM films onto these substrates, followed by thermal annealing under nitrogen, leads to the formation of structured polymer films. We characterize these films with Atomic Force Microscopy (AFM), Raman spectroscopy, and fluorescence microscopy. The surface patterns are effective in guiding phase separation in all of the polymer:PCBM systems investigated, and lead to a rich variety of film morphologies that are inaccessible with unpatterned substrates. We demonstrate our ability to guide pattern formation in films thick enough of be of interest for actual device applications (up to 200 nm in thickness) using feature sizes as small as 100 nm. Finally, we show that the surface chemistry can lead to variations in film morphology on length scales significantly smaller than those used in generating the original surface patterns. The variety of

Clinical and radiographic characteristics of ureteral polyps in children

International Nuclear Information System (INIS)

Niu Zhibing; Wang Changlin; Yang Qi; Hou Ying

2007-01-01

Objective: To analyze the clinical and radiographic characterstics of ureteral polyps with hydronephrosis in children. Methods: Thirteen patients with ureteral polyps and hydronephrosis were studied retrospectively. All patients underwent abdominal plain film, intravenous pyelogram (IVP) and ultrasound (US) examinations,contrast-enhanced CT scan was performed in 10 cases. Results: Intermittent or recurrent abdominal pain with painless hematuria was presented in most cases. Hydronephrosis was demonstrated in radiographic images. IVP delineated the dilatation of the ureter and filling defects within the ureteral lumen in 5 cases. Computed tomography (CT) showed all abnormal changes of ureter and irregular intraluminal soft tissue masses in 6 cases. Moderate and low echoic structures were showed in ureters by US in 2 cases. Conclusion: US and CT, as an important imaging modalities, can improve the diagnostic accuracy for ureteral polyps. (authors)

Mass production of polymer nano-wires filled with metal nano-particles.

Science.gov (United States)

Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

2017-08-17

Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

Semi-metallic, strong and stretchable wet-spun conjugated polymer microfibers

KAUST Repository

Zhou, Jian

2015-01-21

A dramatic improvement in electrical conductivity is necessary to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators. In this study, high-performance poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet-spinning followed by hot-drawing. Due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), we achieved a record electrical conductivity of 2804 S cm−1. This is, to the best of our knowledge, a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S cm−1) and a two-fold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S cm−1). Moreover, we found that these highly conductive fibers experience a semiconductor–metal transition at 313 K. They also have superior mechanical properties with a Young\\'s modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers described here could make them available for conductive smart electronics.

Comparison of polyp size and volume at CT colonography: implications for follow-up CT colonography.

Science.gov (United States)

Bethea, Emily; Nwawka, Ogonna K; Dachman, Abraham H

2009-12-01

The purpose of this study was to evaluate the reliability of polyp measurements at CT colonography and the factors that affect the measurements. Fifty colonoscopically proven cases of polyps 6 mm in diameter or larger were analyzed by two observers who measured each polyp in supine and prone views. Manual measurements of 2D volume by summation of areas, 2D maximum diameter, and 3D maximum diameter and automated measurements of 3D maximum diameter and volume were recorded for each observer and were repeated for one of the observers. Intraobserver and interobserver agreement was calculated. Analysis was performed to determine the measurement parameter that correlated most with summation-of-areas volume. Supine and prone measurements as a surrogate for tracking change in polyp size over time were analyzed to determine the measurement parameter with the least variation. Maximum diameter measured manually on 3D images had the highest correlation with summation-of-areas volume. Manual summation-of-areas volume was found to have the least variation between supine and prone measurements. Linear polyp measurement in the 3D endoluminal view appears to be the most reliable parameter for use in the decision to excise a polyp according to current guidelines. In our study, manual calculation of volume with summation of areas was found to be the most reliable measurement parameter for observing polyp growth over serial examinations. High reliability of polyp measurements is essential for adequate assessment of change in polyp size over serial examinations because many patients with intermediate-size polyps are expected to choose surveillance.

Design and characterization of metal-thiocyanate coordination polymers

OpenAIRE

Savard, Didier

2018-01-01

This thesis focuses on exploring the synthesis and chemical reactivity of thiocyanate-based building blocks of the type [M(SCN)x]y- for the synthesis of coordination polymers. A series of potassium, ammonium, and tetraalkylammonium metal isothiocyanate salts of the type Qy[M(SCN)x] were synthesized and structurally characterized. Most of the salts were revealed to be isostructural and classic Werner complexes, but for (Et4N)3[Fe(NCS)6] and (n-Bu4N)3[Fe(NCS)6], a solid-state size-dependent cha...

Inflammatory myoglandular colorectal polyps: a series of seven cases and review of literature.

Science.gov (United States)

Becheanu, G; Gheorghe, C; Dumbravă, M; Serban-Barbu, V; Diculescu, M

2011-01-01

Inflammatory myoglandular polyp is an unusual but distinct, non-neoplastic type of colorectal polyp, commonly with a distal localization at the recto-sigmoidian level. It was first described in 1992 by Nakamura and his colleagues and it is considered to have few particular histological features. We report a series of seven cases (two male and five female patients) of myoglandular polyps with different localization from 15 to 40 cm from anus. Only four out of seven cases presented with rectal bleeding, the others polyps we incidentally discovered. The polyps varied between 4 and 30 mm in the maximum diameter. Grossly, they had firm consistency and smooth reddish surface. Histological examination of the specimens revealed hyperplastic glands with occasional cystic dilatation, proliferation of smooth muscle with no regular distribution, a variable amount of granulation tissue (usually minimal) and no evidence of epithelial dysplasia. All the lesions were removed endoscopically without any complications. Inflammatory myoglandular polyps are distinct histopathological entities, with insufficiently investigated pathogenesis that can include local trauma, mucosal prolapse or ischemia. Being benign they can be removed endoscopically, surgical treatment being reserved in selected cases.

Low lymphatic vessel density associates with chronic rhinosinusitis with nasal polyps.

Science.gov (United States)

Luukkainen, A; Seppälä, M; Renkonen, J; Renkonen, R; Hagstrő M, J; Huhtala, H; Rautiainen, M; Myller, J; Paavonen, T; Ranta, A; Torkkeli, T; Toppila-Salmi, S

2017-06-01

Chronic rhinosinusitis with and without nasal polyps (CRSwNP and CRSsNP) and antrochoanal polyps (ACP) are different upper airway inflammation phenotypes with different pathomechanisms. In order to understand the development of tissue edema, the present study aimed to evaluate lymphatic vessel density in CRSsNP, CRSwNP and ACP. 120 retrospective nasal and maxillary sinus specimens were stained immunohistochemically with a von Willebrand factor polyclonal antibody recognizing vascular and lymphatic endothelium, and with a podoplanin monoclonal antibody recognizing lymphatic endothelium. Vessels were studied by microscopy in a blinded fashion, and the vessel density and the relative density of lymphatic vessels were calculated. Patient characteristic factors and follow-up data of in average 9 years were collected from patient records. In the nasal cavity, the low absolute and relative density of vessels and of lymphatic vessels was associated with CRSwNP and ACP tissues compared to control inferior turbinate. This was observed also in the inflammatory hotspot area. In the maxillary sinus, lower absolute and relative density of lymphatic vessels associated with the CRSwNP phenotype. High lymphatic vessel density in polyp tissue associated with the need for revision CRS-surgery. As a conclusion, low density of lymphatic vessels distinguished patients with CRSwNP not only in the hotspot area of polyp tissue, but also in maxillary sinus mucosa. Yet, higher lymphatic vessel density seems to associate with polyp recurrence. Further studies are still needed to explore if formation of nasal polyps could be diminished by intranasal therapeutics affecting lymphangiogenesis.

Needle knife-assisted polypectomy in hot snare-resistant fibrotic inflammatory polyps

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Xian-rui Wu

2014-01-01

Full Text Available Background: Inflammatory polyps are common sequelae in patients with inflammatory bowel diseases (IBD. Those polyps can usually be removed with snare polypectomy. There were limited data evaluating the management of hot snare-resistant inflammatory polyps. Methods: We reported on two cases with hot snare-resistant inflammatory polyps, one was a Crohn's disease (CD patient with the polyp at the ileo-colonic anastomosis (ICA and the other one was an ulcerative colitis (UC patient with polyp at the pouch inlet. Results: Sedated endoscopy was performed, which showed a large 2.5 cm pedunculated polyp at the ICA in the first patient and a large 5 cm pedunculated polyp at the pouch inlet in the second patient. Hot snare polypectomy was initially attempted, but failed in both pa- tients. Then endoscopic needle knife polypectomy was performed, which helped complete polypectomy. Both procedures took approximately 25 minutes each. The patients tolerated the procedure well and continued to do well after the procedure. The final pathological diagnoses for both patients were inflammatory polyps with extensive fibrosis. Conclusions: Endoscopic needle knife-assisted polypectomy appeared to be an effective technique for the management of hot snare-resistant inflammatory polyps. Resumo: Experiência: Pólipos inflamatórios são sequelas comuns em pacientes com doença intestinal inflamatória (DII. Geralmente esses pólipos podem ser removidos pela polipectomia por cauterização com laço. São limitados os dados que avaliam o tratamento de pólipos infla- matórios resistentes à cauterização por laço. Métodos: Descrevemos dois casos com pólipos inflamatórios resistentes à cauterização por laço; um deles se tratava de paciente com doença de Crohn (DC com o pólipo na anas-tomose íleo-colônica (AIC, e o outro era paciente de colite ulcerativa (CU com pólipo na entrada da bolsa. Resultados: Foi efetuada uma endoscopia com o paciente sedado

Controlled growth of Au nanoparticles in co-evaporated metal/polymer composite films and their optical and electrical properties

Science.gov (United States)

Takele, H.; Schürmann, U.; Greve, H.; Paretkar, D.; Zaporojtchenko, V.; Faupel, F.

2006-02-01

Nanocomposite films containing Au nanoparticles embedded in a polymer matrix were prepared by vapour phase co-deposition of Au and polymers (Teflon AF and Poly(α -methylstyrene)) in high vacuum. The microstructure of the composite materials as well as metal content strongly depend on the condensation coefficient of the Au atoms, the deposition rates of the components, the substrate temperature, and the type of polymer matrix. The condensation coefficient, which varies between 0.03 and 1, was determined from energy dispersive X-ray spectrometer (EDX) and surface profilometry. It is shown that the microstructure of nanocomposites (size, size distribution, and interparticle separation of metal clusters), which was determined by transmission electron microscopy, can be controlled by the deposition parameters and the choice of polymer matrix. The optical absorption in the visible region due to the particle plasmon resonance has a strong dependence on the metal filling factor. The correlation between the microstructure of nanocomposites and optical properties, studied using UV-Vis spectroscopy, was also established. Further more, the electrical properties of the composites were studied as a function of the metal volume fraction. It was observed that the nanocomposite films exhibit a percolation threshold at a metal volume fraction of 0.43 and 0.20 for gold nanoclusters in Teflon AF and Poly(α-methylstyrene), respectively.

Development of air stable polymer solar cells using an inverted gold on top anode structure

International Nuclear Information System (INIS)

Sahin, Yuecel; Alem, Salima; Bettignies, Remi de; Nunzi, Jean-Michel

2005-01-01

We developed indium-tin-oxide/perylene diimide (or bathocuproine (BCP))/poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) and [6,6]-phenyl C 60 butyric acid methyl ester (PCBM) blend/copper phthalocyanine (CuPc)/Au interpenetrated network polymer solar cells in order to improve air stability. The stability properties of the cells were characterized by current-voltage measurements under the influence of light and air. We achieved long lifetime solar cells which work at least 2 weeks under ambient air conditions without encapsulation. Solar energy conversion efficiency of the cells decrease 30% of the first day value at the end of 2 weeks. Photocurrent absorption properties of the devices were also investigated

A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides

Science.gov (United States)

Rao, B. Narasimha; Suvarna, R. Padma

2016-05-01

Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc.

[Colonic polyps diagnosis by conventional video colonoscopes and chromoscopy with indigo carmine dye solution].

Science.gov (United States)

Nakao, Frank Shigueo; Araújo, Isabella Saraiva; Ornellas, Laura Cotta; Cury, Marcelo de Sousa; Ferrari, Angelo Paulo

2002-01-01

Magnification colonoscopy and contrast chromoscopy with indigo carmine dye solution have been used to differentiate neoplastic polyps (adenomas and adenocarcinomas) from non-neoplastic (hyperplastic, inflammatory, juvenile) in an attempt to obviate endoscopic polypectomy. On the other hand, little published information exists concerning conventional video colonoscopes and chromoscopy for polyp histology prediction. Aim - To assess usefullness of conventional video colonoscopes and contrast chromoscopy with indigo carmine solution for differential diagnosis of colon polyps. In a routine colonoscopy series, we performed chromoscopy with conventional video colonoscopes before endoscopic excision of detected polyps. If a sulcus pattern was observed on the surface of the lesion, it was classified as neoplastic. Polyps were classified as non-neoplastic if no sulcus was detected on its surface. These observations were then compared with histology. In the study period (18 months), we detected 133 polyps in 53 patients. We were able to compare results of histology and chromoscopy in 126 lesions. The sensitivity, specificity, diagnostic accuracy, negative predictive value, and positive predictive value were 56,4%, 79,2%, 65,1%, 52,8%, and 81,5%, respectively. On the base of the presented data, we concluded that conventional video colonoscopes and contrast chromoscopy with indigo carmine solution is not a good technique for differential diagnosis of colon polyps.

Endoscopic mucosal resection for middle and large colorectal polyps with a double-loop snare.

Science.gov (United States)

Yoshida, Naohisa; Saito, Yutaka; Hirose, Ryohei; Ogiso, Kiyoshi; Inada, Yutaka; Yagi, Nobuaki; Naito, Yuji; Otake, Yosuke; Nakajima, Takeshi; Matsuda, Takahisa; Yanagisawa, Akio; Itoh, Yoshito

2014-01-01

This study aimed to analyze the endoscopic mucosal resection (EMR) with a novel uniquely shaped, double-loop snare (Dualoop, Medico's Hirata Inc., Tokyo, Japan) for colorectal polyps. This was a clinical trial conducted in two referral centers, Kyoto Prefectural University of Medicine and National Cancer Center Hospital in Japan. First, the firmness of various snares including 'Dualoop' was experimentally analyzed with a pressure gauge. Five hundred and eighty nine consecutive polyps that underwent EMR with 'Dualoop' were compared to 339 polyps with the standard round snare. Lesion characteristics, en bloc resection, and complications were analyzed. 'Dualoop' had the most firmness among the various snares. The average tumor size was 9.3 mm (5-30), and en bloc resection was achieved in 95.4%. The rate of en bloc resection for middle polyps 15-19 mm in diameter was significantly higher with the 'Dualoop' than that with the round snare (97.9 vs. 80.0%, p < 0.05). The rate of en bloc resection was 64.7% for large polyps ≥20 mm in diameter using 'Dualoop'. Higher age, larger tumor size, and superficial polyps were associated with the failure of en bloc resection. EMR with 'Dualoop' was effective for resecting both middle and large polyps en-bloc. © 2014 S. Karger AG, Basel.

Risk and protective factors for development of colorectal polyps and cancer (Bulgarian experience).

Science.gov (United States)

Kotzev, I; Mirchev, M; Manevska, B; Ivanova, I; Kaneva, M

2008-01-01

Colorectal cancer takes third place among all malignancies in the Varna region. The present study aims to determine the typical and distinguishing risk and protective factors for colorectal polyps and cancer formation. 166 patients with large bowel polyps and 107 patients with colorectal cancer were questioned, examined endoscopically and histologically. Logistic regression analysis was used to find a possible correlation between alimentary habits, way of life, and risk for colorectal polyps and cancer formation. The latter have been used to define a strategy for their prevention. Our results showed that fried, preserved, and grilled meat, consumption of animal fats, sugar, and being overweight are positively associated with colorectal polyps. In contrast, consumption of fruit, vegetables, rye- and brown bread, green tea, vegetable food, yoghourt, vegetarian food, fish, lamb, hare, garlic, boiled food, and mineral water, have strong protective effect against large bowel polyps. We have confirmed the role of the well-known risk factors for colorectal cancer, and discovered an association between H. pylori infection, age, villous component in the adenomatous polyps, and family history for any neoplasia and large bowel carcinoma. We suggest the following protective factors for CRC: vegetarian food, plant oil, rural life, aspirin intake, legumes, fish, fruit and vegetable consumption. We observe a similarity between the risk factors for colorectal polyps and cancer formation. They act simultaneously and depend on genetic predisposition. A combination of endoscopic treatment and correction of the alimentary factors could be used as a means of cancer prevention.

Nilotinib Induced Recurrent Gastric Polyps: Case Report and Review of Literature.

Science.gov (United States)

Kassem, Nancy; Ismail, Omar M; Elomri, Halima; Yassin, Mohamad A

2017-07-14

BACKGROUND Tyrosine kinase inhibitors (TKIs) are currently an important targeted drug class in the treatment of chronic myeloid leukemia (CML). Imatinib was the first approved TKI for CML in 2001. Nilotinib is a second-generation TKI, approved in 2007; it inhibits BCR-ABL, PDGFR, and c-KIT, and is 30 times more potent than imatinib. Tyrosine kinase enzymes are expressed in multiple tissues and are involved in several signaling pathways; they have been shown to have several off-target side effects. CASE REPORT We report a case of an elderly male with CML and no history of gastrointestinal diseases, treated with nilotinib, and developed recurrent gastric polyps after three years of treatment. We excluded common causes of gastric polyps and therefore considered nilotinib as a probable cause of recurrent gastric polyps. CONCLUSIONS Recurrent gastric polyps could be a potential side effect of nilotinib treatment. Careful long-term monitoring of patients on TKI therapy is necessary and further long-term studies of TKI side effects are needed.

How does the serrated polyp pathway alter CRC screening and surveillance?

Science.gov (United States)

Kahi, Charles J

2015-03-01

Screening and surveillance for colorectal cancer (CRC) reduces mortality through the detection of early-stage adenocarcinoma, and more importantly the detection and removal of premalignant polyps. While adenomas have historically been considered the most common and screening-relevant precursor lesions, there is accumulating evidence showing that the serrated pathway is an important contributor to CRC, and a disproportionate contributor to interval or postcolonoscopy CRC, particularly in the proximal colon. The serrated pathway is characterized by mutations in the BRAF gene, high levels of methylation of promoter CpG islands (CIMP-high), and the sessile serrated adenoma/polyp (SSA/P) is the most important precursor lesion. The study of serrated polyps has been complicated by evolving nomenclature, substantial variation among pathologists in the identification of SSA/Ps, high variability in endoscopic detection rates, and uncertainty regarding the relation to synchronous and metachronous colonic neoplasia. This paper presents an overview of the serrated polyp pathway and discusses its clinical implications including its impact on CRC screening.

A large hymenal polyp in a 21-year-old virgin:

OpenAIRE

Borko, Elko; Došen, Marko; Kavalar, Rajko; Pivec, Gregor; Žebeljan, Ivan

2009-01-01

Pathological conditions of the hymen are rare in everyday medical practice. They are usually encountered in the pediatric patient population and are sometimes a matter of forensic interest. We report an interesting case of a large hymenal polyp in an adolescent virgin that presented only a cosmetic problem. The polyp was excised, the hymenal ring was preserved, and the sample was histologically verified.

Influence of intensive light exposure on the complex impedance of polymer light-emitting diodes

Directory of Open Access Journals (Sweden)

Fábio Rogério Cury

2008-06-01

Full Text Available In this work we investigated the effect of visible radiation on the electrical properties of poly[(2-methoxy-5-hexyloxy-p-phenylenevinylene]- MH-PPV films and light emitting diodes. Complex impedance measurements of (Au or ITO/MH-PPV/(Au or Al samples were carried out at room temperature and exposed to white light. Over the frequency range from 100 mHz to 2 MHz, the electrical results of Au/MH-PPV/Au was dominated by the Cole-Cole approach, where the electrode influence is negligible. However, some additional influence of the interface was observed to occur when Al was used as electrode. These effects were observed under both dark and visible-light illumination conditions. A simple model based on resistor-capacitor parallel circuits was developed to represent the complex impedance of the samples, thereby separating bulk and interface contributions. We observed that the polymer electrical resistivity decreased while the dielectric constant of the polymer and the thickness of the Al/MH-PPV layer were almost constant with increasing light intensity. The decrease of the polymer layer resistance comes from a better charge injection due to a light induced dissociation of positive charge carriers at the electrode.

Molecularly Imprinted Polymer/Metal Organic Framework Based Chemical Sensors

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Zhenzhong Guo

2016-10-01

Full Text Available The present review describes recent advances in the concept of molecular imprinting using metal organic frameworks (MOF for development of chemical sensors. Two main strategies regarding the fabrication, performance and applications of recent sensors based on molecularly imprinted polymers associated with MOF are presented: molecularly imprinted MOF films and molecularly imprinted core-shell nanoparticles using MOF as core. The associated transduction modes are also discussed. A brief conclusion and future expectations are described herein.

Semi-Interpenetrating Polymer Networks with Predefined Architecture for Metal Ion Fluorescence Monitoring

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Kyriakos Christodoulou

2016-11-01

Full Text Available The development of new synthetic approaches for the preparation of efficient 3D luminescent chemosensors for transition metal ions receives considerable attention nowadays, owing to the key role of the latter as elements in biological systems and their harmful environmental effects when present in aquatic media. In this work, we describe an easy and versatile synthetic methodology that leads to the generation of nonconjugated 3D luminescent semi-interpenetrating amphiphilic networks (semi-IPN with structure-defined characteristics. More precisely, the synthesis involves the encapsulation of well-defined poly(9-anthrylmethyl methacrylate (pAnMMA (hydrophobic, luminescent linear polymer chains within a covalent poly(2-(dimethylaminoethyl methacrylate (pDMAEMA hydrophilic polymer network, derived via the 1,2-bis-(2-iodoethoxyethane (BIEE-induced crosslinking process of well-defined pDMAEMA linear chains. Characterization of their fluorescence properties demonstrated that these materials act as strong blue emitters when exposed to UV irradiation. This, combined with the presence of the metal-binding tertiary amino functionalities of the pDMAEMA segments, allowed for their applicability as sorbents and fluorescence chemosensors for transition metal ions (Fe3+, Cu2+ in solution via a chelation-enhanced fluorescence-quenching effect promoted within the semi-IPN network architecture. Ethylenediaminetetraacetic acid (EDTA-induced metal ion desorption and thus material recyclability has been also demonstrated.

Polymer quenched prealloyed metal powder

Science.gov (United States)

Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

2001-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Nasal polyps. A clinical radiological histopathological and mycological study

Energy Technology Data Exchange (ETDEWEB)

Babiker, Babiker Eltayeb [Faculty of Medicine, University of Khartoum, Khartoum (Sudan)

1997-12-01

Forty patients with nasal polyposis were studied. This study included clinical, haematological and mycological aspects. There were 24 females (60% of patients) and 16 males (40%). We found that all patients presented with nasal obstruction and nasal tone and the majority of them had allergic nasal symptoms such as sneezing and watery discharge. Thirty five percent of the patients were recurrent cases, being operated before for nasal polyps. Radiological investigations showed high of sinusitis and that 10% of the patients had complicated disease with orbital or intracranial extensions. Mycological studies revealed the presence of fungal infection in 4 patient (10%) and it was caused by Aspergillus flavus. Histological studies identified the allergic nature of the polyps in all patients. Surgical treatment was carried out in all patients and operations varied from simple intranasal polypectomy, intranasal ethmiodectomy, external ethmoidectomy to Caldwell-Luc operation for patients with antrochanal polyps.(Author)

Thermal and Osmotic Tolerance of 'Irukandji' Polyps: Cubozoa; Carukia barnesi.

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Robert Courtney

Full Text Available This research explores the thermal and osmotic tolerance of the polyp stage of the Irukandji jellyfish Carukia barnesi, which provides new insights into potential polyp habitat suitability. The research also targets temperature, salinity, feeding frequency, and combinations thereof, as cues for synchronous medusae production. Primary findings revealed 100% survivorship in osmotic treatments between 19 and 46‰, with the highest proliferation at 26‰. As salinity levels of 26‰ do not occur within the waters of the Great Barrier Reef or Coral Sea, we conclude that the polyp stage of C. barnesi is probably found in estuarine environments, where these lower salinity conditions commonly occur, in comparison to the medusa stage, which is oceanic. Population stability was achieved at temperatures between 18 and 31°C, with an optimum temperature of 22.9°C. We surmise that C. barnesi polyps may be restricted to warmer estuarine areas where water temperatures do not drop below 18°C. Asexual reproduction was also positively correlated with feeding frequency. Temperature, salinity, feeding frequency, and combinations thereof did not induce medusae production, suggesting that this species may use a different cue, possibly photoperiod, to initiate medusae production.

Production of large-area polymer solar cells by industrial silk screen printing, lifetime considerations and lamination with polyethyleneterephthalate

DEFF Research Database (Denmark)

Krebs, Frederik C; Alstrup, J.; Spanggaard, H.

2004-01-01

The possibility of making large area (100 cm(2)) polymer solar cells based on the conjugated polymer poly 1,4-(2-methoxy-5-ethylhexyloxy)phenylenevinylene (MEH-PPV) was demonstrated. Devices were prepared by etching an electrode pattern on ITO covered polyethyleneterephthalate (PET) substrates....... A pattern of conducting silver epoxy allowing for electrical contacts to the device was silk screen printed and hardened. Subsequently a pattern of MEH-PPV was silk screen printed in registry with the ITO electrode pattern on top of the substrate. Final evaporation of an aluminum electrode or sublimation......). The half-life based on I-sc in air for the devices were 63 h. The cells were laminated in a 125 mum PET encasement. Lamination had a negative effect on the lifetime. We demonstrate the feasibility of industrial production of large area solar cells (1 m(2)) by silk screen printing and envisage...

Computer-aided diagnosis of colonic polyp by CT colonography

International Nuclear Information System (INIS)

Yoshida, Hiroyuki

2007-01-01

The outcome of National CT Colonography Trial, by American College of Radiology Imaging Network, 2006 (www.acrin.org/6664 protocol), possibly leads to the introduction of colorectal cancer screening in the US because CT colonography (CTCG) has been approved in the health insurance system. This paper describes the outline of computer-aided diagnosis (CAD) of colonic polyp by CTCG, its polyp detectability and future aspects. CTCG essentially derives from the virtual, abdominal 3D CT images and gives as many as about 500 images/patient, in the reading of which CAD support the expert. CAD technology in CTCG is said to have been essentially established in the first half of 2000s, which involves the cleansing of fecal tagging effect, extraction of the colonal wall from the image, detection of suspicious polyp, reduction of false-positive findings and displaying of the detected polyp. The detectability is thought to be at comparable level to expert's. The last displaying is done on the user-interface like Colon CAD Workstation. More efficient expert's reading with CAD, imaging without previous gut cleansing, detection of the flat lesion and further reduction of false-positive are the forthcoming tasks in clinical practice. Significance of CTCG is becoming in realization and its usage with CAD is thought to be more popular in Japan. (R.T.)

Double-contrast gastrography and gastroscopy in the diagnosis of gastric polyps. Personal experience

Energy Technology Data Exchange (ETDEWEB)

Biscarini, R; Giorgi, G; Lazzari, G and others

1986-01-01

Gastric polyps are benign tumors which have been less uncommonly detected in recent years, due to the refinement of both radiologic and endoscopic investigations. From 1981 through 1985 gastric polyps were detected in 102 patients (1,9%) out of 5368 radiologic examination. In the same period, 98 cases (3,3%) were detected out of 2942 endoscopic examination. The comparison of data in these two series shows a superimposition. Despite an increased percentage of endoscopic findings (to some extent due to previous radiologic reports), the authors assert the diagnostic efficacy of double contrast radiologic investigation as a first approach to benign polypous lesions of the stomach. As far as histology is concerned, a clear prevalence is shown of hyperplastic versus adenomatous polyps (90 and 8 cases repectively).

Arrays of hollow out-of-plane microneedles made by metal electrodeposition onto solvent cast conductive polymer structures

International Nuclear Information System (INIS)

Mansoor, I; Liu, Y; Stoeber, B; Häfeli, U O

2013-01-01

Transdermal drug delivery using microneedles is a technique to potentially replace hypodermic needles for injection of many vaccines and drugs. Fabrication of hollow metallic microneedles so far has been associated with time-consuming steps that restrict batch production of these devices. Here, we are presenting a novel method for making metallic microneedles with any desired height, spacing, and lumen size. In our process, we use solvent casting to coat a mold, which contains an array of pillars, with a conductive polymer composite layer. The conductive layer is then used as a seed layer in a metal electrodeposition process. To characterize the process, the conductivity of the polymer composite with respect to different filler concentrations was investigated. In addition, plasma etching of the polymer was characterized. The electroplating process was also studied further to control the thickness of the microneedle array plate. The strength of the microneedle devices was evaluated through a series of compression tests, while their performance for transdermal drug delivery was tested by injection of 2.28 µm fluorescent microspheres into animal skin. The fabricated metallic microneedles seem appropriate for subcutaneous delivery of drugs and microspheres. (paper)

Polyp bailout in Pocillopora damicornis following thermal stress [version 2; referees: 2 approved

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Alexander J Fordyce

2017-08-01

Full Text Available Polyp bailout is an established but understudied coral stress response that involves the detachment of individual polyps from the colonial form as a means of escaping unfavourable conditions. This may influence both the mortality and asexual recruitment of coral genotypes across a range of species. It has been observed in response to numerous stressors including high salinity and low pH. Polyp expulsion in association with thermal stress has once been described in a geographically restricted, temperate species. We therefore cannot reliably apply this observation to tropical coral reefs around the world, which are increasingly under threat from thermal stress events. We present the first qualitative observation of polyp bailout following acute temperature shock  in a near-natural mesocosm experiment. Detached polyps show similar characteristics to those described in previous studies, including the retention of endosymbiotic zooxanthellae and the ability to disperse across short distances. This finding strongly suggests that polyp bailout occurs in tropical coral reef environments and warrants further detailed research into the implication of this response in terms of individual survival, rapid migration into cooler micro-habitats and local recruitment within the reef environment and its coral community.

Computer-aided polyp detection on CT colonography: Comparison of three systems in a high-risk human population

International Nuclear Information System (INIS)

Park, Hee Sun; Kim, Se Hyung; Kim, Jong Hyo; Lee, June-Goo; Kim, Sang Gyun; Lee, Jeong Min; Lee, Jae Young; Han, Joon Koo; Choi, Byung Ihn

2010-01-01

Purpose: To compare the detection performances of two commercial and one academic computer-aided diagnosis (CAD) systems for polyp detection on CT colonography (CTC) in a high-risk human population and to assess their detection characteristics. Materials and methods: This retrospective study had institutional review board approval, but informed consent was waived. Sixty-eight patients who were suspected of having colonic polyps and scheduled for colonoscopic polyp removal were included. After CTC was performed using a 64-row MDCT, two commercial (PEV, CAR) and one academic (Hessian matrix-based) CAD systems were applied to each CTC dataset. Colonoscopy using the segmental unblinded technique was performed as a standard of reference. Per-polyp and per-patient sensitivities were calculated and compared for each CAD system. The mean number of false-positives (FPs) and false-negatives (FNs) was computed and the causes of all FPs and FNs were analyzed. Results: A total of 151 polyps in 61 patients were detected (77 polyps <6 mm, 48 6-9.9 mm, 26 ≥ 10 mm). Per-polyp sensitivity for PEV, CAR, and Hessian matrix-based CAD were: 71.6%, 78.4%, and 83.8% for polyps ≥6 mm, and 88.5%, 96.2%, and 96.2% for polyps ≥10 mm. Per-patient sensitivity for polyps ≥6 mm was 80.4%, 89.1%, and 93.5%, and 87%, 95.7%, and 95.7% for polyps ≥10 mm, respectively. Per-polyp and per-patient sensitivities were not significantly different among the three CAD systems regardless of size threshold. Mean number of FPs was 6.9 for PEV, 7.3 for CAR, and 14 for Hessian matrix-based CAD. The most common cause of FPs were feces, followed by extracolonic findings, prominent folds and ileocecal valve, and rectal tube. The distribution of the causes of FPs was significantly different among the three systems. Conclusion: Sensitivity of the three CAD systems for polyp detection was comparable regardless of the polyp size threshold; however, the number of FPs was higher in the Hessian matrix-based CAD

Transformation of metal-organic framework to polymer gel by cross-linking the organic ligands preorganized in metal-organic framework.

Science.gov (United States)

Ishiwata, Takumi; Furukawa, Yuki; Sugikawa, Kouta; Kokado, Kenta; Sada, Kazuki

2013-04-10

Until now, seamless fusion of metal-organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now.

Cytogenetic comparisons of synchronous carcinomas and polyps in patients with colorectal cancer

DEFF Research Database (Denmark)

Bardi, G; Parada, L A; Bomme, L

1997-01-01

Thirty tumorous lesions from seven patients with colorectal cancer were short-term cultured and cytogenetically analysed: 16 non-adenomatous polyps, six adenomas, seven carcinomas, including one in polyp, and one lymph node metastasis. Clonal chromosome aberrations were found in 20 samples in 100...

Placental polyp: a rare cause of iron deficiency anemia

Directory of Open Access Journals (Sweden)

Fernando Peixoto Ferraz de Campos

2011-12-01

Full Text Available Placental polyps are defined as pedunculated or polypoid fragments of placentaor ovular membranes retained for an indefinite period of time into the uterus afterabortion or child birth. An important cause of retention is placental accretism, anabnormal adherence of the placenta into the uterine wall. Chronic cases are rarelyreported in the literature. In these cases, the placental retention in the immediatepostpartum is not followed by heavy bleeding what makes the diagnosischallenging. We report a rare case of iron-deficiency anemia in a multiparous29-year-old female patient two years after the last delivery. She sought medicalcare with clinical symptoms of anemia and recent menses alterations. Therewas no history of abortion. On gynecological examination, there was a twofoldenlarged uterus, and the pelvic ultrasound revealed an image compatible with anendometrial polyp. She underwent open hysterectomy because of uncontrollablebleeding followed by hypotension after curettage. The histolopathologicexamination revealed a partially hyalinized and necrotic placental polyp.

[Fibroepithelial polyp of the ureter. Report of one case].

Science.gov (United States)

Morales, Raúl; Manrique, Eduardo; Casanova, Rubén; Molina, Pedro; Falcón, Ramón

2004-05-01

To report the rare case of a patient with a ureteral polyp. We describe the case of a 55-year-old female patient receiving care at the Celia Sanchez Manduley University Hospital in Manzanillo, Cuba, who was fortuitously diagnosed of a fibroepithelial polyp of the right ureter during the work up and treatment of an ovarian tumor. This case is the first of its kind in this hospital after 22 years, which confirms the rarity of ureteral tumors, specifically those of benign etiology. The absence of symptoms, specifically hematuria and pain, does not correspond to the reviewed articles. The chosen treatment was exeresis of the polyp at its base and frozen biopsy, followed by re-establishment of the urinary passage, as various authors recommend. Currently the endoscopical approach is recommended for its multiple advantages. We conclude that this disease is very rare, may have a symptomatic course and the treatment of choice is surgery with very good results.

Hybrid device based on GaN nanoneedles and MEH-PPV/PEDOT:PSS polymer

International Nuclear Information System (INIS)

Shin, Min Jeong; Gwon, Dong-Oh; Lee, Chan-Mi; Lee, Gang Seok; Jeon, In-Jun; Ahn, Hyung Soo; Yi, Sam Nyung; Ha, Dong Han

2015-01-01

Highlights: • A hybrid device was demonstrated by using MEH-PPV, PEDOT:PSS, and GaN nanoneedles. • I–V curve of the hybrid device showed its rectification behaviour, similar to a diode. • EL peak originated by the different potential barriers at MEH-PPV and GaN interface. - Abstract: A hybrid device that combines the properties of organic and inorganic semiconductors was fabricated and studied. It incorporated poly[2-methoxy-5-(2-ethylhexyloxy)- 1,4-phenylenevinylene] (MEH-PPV) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as organic polymers and GaN nanoneedles as an inorganic semiconductor. Layers of the two polymers were spin coated on to the GaN nanoneedles. The one peak in the electroluminescence spectrum originated from the MEH-PPV layer owing to the different potential barriers of electrons and holes at its interface with the GaN nanoneedles. However, the photoluminescence spectrum showed peaks due to both GaN nanoneedles and MEH-PPV. Such hybrid structures, suitably developed, might be able to improve the efficiency of optoelectronic devices

Hybrid device based on GaN nanoneedles and MEH-PPV/PEDOT:PSS polymer

Energy Technology Data Exchange (ETDEWEB)

Shin, Min Jeong; Gwon, Dong-Oh; Lee, Chan-Mi; Lee, Gang Seok [Department of Applied Science, Korea Maritime and Ocean University, Busan 606-791 (Korea, Republic of); Jeon, In-Jun [Department of Nano-semiconductor Engineering, Korea Maritime and Ocean University, Busan 606-791 (Korea, Republic of); Ahn, Hyung Soo [Department of Applied Science, Korea Maritime and Ocean University, Busan 606-791 (Korea, Republic of); Department of Nano-semiconductor Engineering, Korea Maritime and Ocean University, Busan 606-791 (Korea, Republic of); Yi, Sam Nyung, E-mail: snyi@kmou.ac.kr [Department of Applied Science, Korea Maritime and Ocean University, Busan 606-791 (Korea, Republic of); Department of Nano-semiconductor Engineering, Korea Maritime and Ocean University, Busan 606-791 (Korea, Republic of); Ha, Dong Han [Division of Convergence Technology, Korea Research Institute of Standards and Science, Daejeon 305-340 (Korea, Republic of)

2015-08-15

Highlights: • A hybrid device was demonstrated by using MEH-PPV, PEDOT:PSS, and GaN nanoneedles. • I–V curve of the hybrid device showed its rectification behaviour, similar to a diode. • EL peak originated by the different potential barriers at MEH-PPV and GaN interface. - Abstract: A hybrid device that combines the properties of organic and inorganic semiconductors was fabricated and studied. It incorporated poly[2-methoxy-5-(2-ethylhexyloxy)- 1,4-phenylenevinylene] (MEH-PPV) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as organic polymers and GaN nanoneedles as an inorganic semiconductor. Layers of the two polymers were spin coated on to the GaN nanoneedles. The one peak in the electroluminescence spectrum originated from the MEH-PPV layer owing to the different potential barriers of electrons and holes at its interface with the GaN nanoneedles. However, the photoluminescence spectrum showed peaks due to both GaN nanoneedles and MEH-PPV. Such hybrid structures, suitably developed, might be able to improve the efficiency of optoelectronic devices.

Respiratory response to temperature of three populations of Aurelia aurita polyps in northern Europe.

Directory of Open Access Journals (Sweden)

Danja P Höhn

Full Text Available The benthic life stage (polyp or scyphistoma of the bloom-forming jellyfish, Aurelia aurita (Linnaeus, 1759, also known as the moon jellyfish, contributes to the seasonal occurrence and abundance of medusa blooms via asexual reproduction. A. aurita is widely distributed in coastal areas in northern Europe, and one of the most studied jellyfish species. While the physiology of the visible medusa is largely understood, understanding of the physiology of the perennial benthic life-stage is scarce. To measure the physiological tolerance of A. aurita, the scyphistoma's temperature sensitivity across its distributional range was investigated. Respiration rates of polyps from three northern European locations exposed to 11 temperatures between 2 and 22°C were measured. There was a significant difference in respiration rate among the three polyp populations, which may reflect on differences in their thermal tolerance window. A critical temperature was reached at 14°C with the metabolic rate decreasing below and above that temperature. This pattern was less pronounced in the Norwegian population but polyps were able to survive, at least temporarily, those temperatures exceeding their natural range. While polyps collected from northern Norway, with a narrow environmental thermal window, displayed a low baseline metabolism with a Q10 value of 1.2, polyps from southern England and Scotland had Q10 values of 1.6 and 2.5, respectively. Differences in polyps' respiration rates across their distributional range suggest that populations have evolved adaptations to local environmental thermal conditions.

Chemical potential pinning due to equilibrium electron transfer at metal/C60-doped polymer interfaces

Science.gov (United States)

Heller, C. M.; Campbell, I. H.; Smith, D. L.; Barashkov, N. N.; Ferraris, J. P.

1997-04-01

We report electroabsorption measurements of the built-in electrostatic potential in metal/C60-doped polymer/metal structures to investigate chemical potential pinning due to equilibrium electron transfer from a metal contact to the electron acceptor energy level of C60 molecules in the polymer film. The built-in potentials of a series of structures employing thin films of both undoped and C60-doped poly[2-methoxy, 5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were measured. For undoped MEH-PPV, which has an energy gap of about 2.4 eV, the maximum built-in potential is about 2.1 eV, whereas for C60-doped MEH-PPV the maximum built-in potential decreases to 1.5 eV. Electron transfer to the C60 molecules close to the metal interface pins the chemical potential of the metal contact near the electron acceptor energy level of C60 and decreases the built-in potential of the structure. From the systematic dependence of the built-in potential on the metal work function we find that the electron acceptor energy level of C60 in MEH-PPV is about 1.7 eV above the hole polaron energy level of MEH-PPV.

Conjugated Polymer Chains Confined in Vertical Nanocylinders of a Block-Copolymer Film: Preparation, Characterization, and Optoelectronic Function

KAUST Repository

Dong, Ban Xuan; Honmou, Yoshihiro; Komiyama, Hideaki; Furumaki, Shu; Iyoda, Tomokazu; Vacha, Martin

2013-01-01

Hybrid materials composed of phase-separated block copolymer films and conjugated polymers of the phenylenevinylene family (PPV) are prepared. The PPV chains are embedded in vertical cylinders of nanometer diameter in the block-copolymer films. The cylinders span continuously the whole film thickness of 70 nm. Incorporation of the PPV chains into the one-dimensional cylinders leads to modified photoluminescence spectra and to large absorption anisotropy. The hybrid films show electroluminescence from the PPV chains in a simple light-emitting device at minute doping concentrations, and also exhibit a factor of 19 increase in electron transport efficiency along the single PPV chains. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conjugated Polymer Chains Confined in Vertical Nanocylinders of a Block-Copolymer Film: Preparation, Characterization, and Optoelectronic Function

KAUST Repository

Dong, Ban Xuan

2013-01-15

Hybrid materials composed of phase-separated block copolymer films and conjugated polymers of the phenylenevinylene family (PPV) are prepared. The PPV chains are embedded in vertical cylinders of nanometer diameter in the block-copolymer films. The cylinders span continuously the whole film thickness of 70 nm. Incorporation of the PPV chains into the one-dimensional cylinders leads to modified photoluminescence spectra and to large absorption anisotropy. The hybrid films show electroluminescence from the PPV chains in a simple light-emitting device at minute doping concentrations, and also exhibit a factor of 19 increase in electron transport efficiency along the single PPV chains. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-dimensional laryngeal flow fields induced by a model vocal fold polyp

Energy Technology Data Exchange (ETDEWEB)

Erath, Byron D., E-mail: erath@gwu.edu [Department of Mechanical and Aerospace Engineering, George Washington University, 801 22nd Street NW, 739 Phillips Hall, Washington, DC 20052 (United States); Plesniak, Michael W., E-mail: plesniak@gwu.edu [Department of Mechanical and Aerospace Engineering, George Washington University, 801 22nd Street NW, 739 Phillips Hall, Washington, DC 20052 (United States)

2012-06-15

Highlights: Black-Right-Pointing-Pointer Pathological speech with a unilateral polyp is modeled in a scaled-up flow facility. Black-Right-Pointing-Pointer Vortex shedding from the polyp disrupts normal flow behavior. Black-Right-Pointing-Pointer Hairpin vortices create spatial velocity asymmetries in the glottal flow. - Abstract: Pathological laryngeal flow fields are investigated in a dynamically-driven, scaled-up model of the vocal folds. Disruption of the flow field due to the presence of a geometric protuberance, representative of a sessile unilateral polyp, is investigated in both the streamwise and transverse flow directions using phase-averaged particle image velocimetry. It is shown that the protuberance disrupts the normal flow behavior of the glottal jet throughout the phonatory cycle. During the divergent portions of the glottal cycle, the flow is characterized by the formation of hairpin vortices downstream of the protuberance. The protuberance also introduces significant velocity gradients in the anterior-posterior direction, which cover {approx}30 - 40% of the vocal fold length. It is proposed that the disruption of the normal velocity behavior owing to the presence of a polyp will adversely impact the aerodynamic loadings that drive vocal fold motion, contributing to the temporal and spatial vocal fold asymmetries that are clinically-observed in patients with unilateral polyps.

Three-dimensional laryngeal flow fields induced by a model vocal fold polyp

International Nuclear Information System (INIS)

Erath, Byron D.; Plesniak, Michael W.

2012-01-01

Highlights: ► Pathological speech with a unilateral polyp is modeled in a scaled-up flow facility. ► Vortex shedding from the polyp disrupts normal flow behavior. ► Hairpin vortices create spatial velocity asymmetries in the glottal flow. - Abstract: Pathological laryngeal flow fields are investigated in a dynamically-driven, scaled-up model of the vocal folds. Disruption of the flow field due to the presence of a geometric protuberance, representative of a sessile unilateral polyp, is investigated in both the streamwise and transverse flow directions using phase-averaged particle image velocimetry. It is shown that the protuberance disrupts the normal flow behavior of the glottal jet throughout the phonatory cycle. During the divergent portions of the glottal cycle, the flow is characterized by the formation of hairpin vortices downstream of the protuberance. The protuberance also introduces significant velocity gradients in the anterior-posterior direction, which cover ∼30 − 40% of the vocal fold length. It is proposed that the disruption of the normal velocity behavior owing to the presence of a polyp will adversely impact the aerodynamic loadings that drive vocal fold motion, contributing to the temporal and spatial vocal fold asymmetries that are clinically-observed in patients with unilateral polyps.

Modeling and control of a self-sensing polymer metal composite actuator

International Nuclear Information System (INIS)

Nam, Doan Ngoc Chi; Ahn, Kyoung Kwan

2014-01-01

An ion polymer metal composite (IPMC) is an electro-active polymer (EAP) that bends in response to a small applied electrical field as a result of mobility of cations in the polymer network and vice versa. One drawback in the use of an IPMC is the sensing problem for such a small size actuator. The aim of this paper is to develop a physical model for a self-sensing IPMC actuator and to verify its applicability for practical position control. Firstly, ion dynamics inside a polymer membrane is investigated with an asymmetric solution in the presence of distributed surface resistance. Based on this analysis, a modified equivalent circuit and a simple configuration to realize the self-sensing IPMC actuator are proposed. Mathematical modelling and experimental evaluation indicate that the bending curvature can be obtained accurately using several feedback voltage signals along with the IPMC length. Finally, the controllability of the developed self-sensing IPMC actuator is investigated using a robust position control. Experimental results prove that the self-sensing characteristics can be applied in engineering control problems to provide a more convenient sensing method for IPMC actuating systems. (paper)

THE PREVALENCE OF COLONIC POLYPS IN PATIENTS WITH ACROMEGALY: A CASE-CONTROL, NESTED IN A COHORT COLONOSCOPIC STUDY.

Science.gov (United States)

Gonzalez, Baldomero; Vargas, Guadalupe; Mendoza, Victoria; Nava, Mariana; Rojas, Moisés; Mercado, Moisés

2017-05-01

Acromegaly is associated with an increased risk of colonic polyps. The magnitude of such risk is controversial, and the characteristics that distinguish patients who develop polyps from those who do not are not well established. This study was performed to determine the prevalence of colonic polyps upon the diagnosis of acromegaly and to compare the clinical and biochemical features of patients with and without polyps. Out of 165 patients who underwent a full colonoscopy upon diagnosis of acromegaly, 53 were found to harbor colonic lesions (cases), whereas the remaining 112 were used as controls. Demographic, clinical, and biochemical characteristics were compared between the 2 groups. The prevalence of colonic polyps was 32%, with an estimated relative risk of 6.21 (95% confidence interval [CI] 4.08-9.48). Adenomatous and nonadenomatous polyps were found in 22 and 31 patients, respectively. The most common location was the descending colon. Compared to patients without polyps, subjects with polyps were somewhat older and had significantly higher insulin-like growth factor-1 (IGF-1) levels and a higher prevalence of diabetes. Upon multivariate analysis, only IGF-1 level at diagnosis remained significantly associated with colonic polyps in general and with hyperplastic polyps in particular. Acromegaly is associated with an elevated risk of developing colonic polyps, particularly, distally located hyperplastic lesions. Except for a higher IGF-1 level at diagnosis, no distinctive clinical or biochemical features can be found among those who develop polyps compared to those who do not. CI = confidence interval GH = growth hormone IGF-1 = insulin-like growth factor 1 IQR = inter-quartile range RR = relative risk ULN = upper limit of normal.

Implantable polymer/metal thin film structures for the localized treatment of cancer by Joule heating

Science.gov (United States)

Kan-Dapaah, Kwabena; Rahbar, Nima; Theriault, Christian; Soboyejo, Wole

2015-04-01

This paper presents an implantable polymer/metal alloy thin film structure for localized post-operative treatment of breast cancer. A combination of experiments and models is used to study the temperature changes due to Joule heating by patterned metallic thin films embedded in poly-dimethylsiloxane. The heat conduction within the device and the surrounding normal/cancerous breast tissue is modeled with three-dimensional finite element method (FEM). The FEM simulations are used to explore the potential effects of device geometry and Joule heating on the temperature distribution and lesion (thermal dose). The FEM model is validated using a gel model that mimics biological media. The predictions are also compared to prior results from in vitro studies and relevant in vivo studies in the literature. The implications of the results are discussed for the potential application of polymer/metal thin film structures in hyperthermic treatment of cancer.

PET/CT colonography in patients with colorectal polyps: a feasibility study

International Nuclear Information System (INIS)

Mainenti, Pier P.; Pace, Leonardo; Salvatore, Marco; Salvatore, Barbara; D'Antonio, Dario; Bucci, Luigi; De Falco, Teresa; De Palma, Giovanni D.; D'Armiento, Francesco P.

2007-01-01

To examine: (1) the feasibility of PET/CT colonography (PET/CTc) in patients with colorectal polyps; (2) the impact of metabolic information on CTc interpretation and, conversely, the impact of morphological information on PET characterisation of focal colorectal uptake. Ten patients with colorectal polyps underwent PET/CTc, followed within 3 h by therapeutic conventional colonoscopy (CC). A radiologist and a nuclear medicine physician analysed the PET/CTc images. The agreement of morphological and metabolic information in the colon and rectum was evaluated. The sensitivity and specificity of PET, CT and PET/CT were calculated for colorectal polyps. Seventeen polypoid lesions were identified at CC: six≤5 mm, six between 6 and 9 mm, and five ≥10 mm (four hyperplastic polyps, 11 tubular adenomas, one adenocarcinoma and one submucosal lipoma). A total of 20 scans (supine and prone) were performed in the ten patients: the agreement of morphological and metabolic information was excellent in 17 scans, good in two and moderate in one. PET/CTc showed a sensitivity of 91% for lesions ≥6 mm and a specificity of 100%. The metabolic information did not disclose any further polyps missed on CTc. The morphological information permitted correct classification of all eight instances of focal radiotracer uptake. PET/CTc is a feasible study. Adding a colonographic protocol to PET/CT images seems to allow correct characterisation of all cases of colorectal focal radiotracer uptake. The metabolic information does not seem to increase the accuracy of CTc. (orig.)

Metal-catalyzed living radical polymerization and radical polyaddition for precision polymer synthesis

Energy Technology Data Exchange (ETDEWEB)

Mizutani, M; Satoh, K [Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Kamigaito, M, E-mail: kamigait@apchem.nagoya-u.ac.j

2009-08-01

The metal-catalyzed radical addition reaction can be evolved into two different polymerization mechanisms, i.e.; chain- and step-growth polymerizations, while both the polymerizations are based on the same metal-catalyzed radical formation reaction. The former is a widely employed metal-catalyzed living radical polymerization or atom transfer radical polymerization of common vinyl monomers, and the latter is a novel metal-catalyzed radical polyaddition of designed monomer with an unconjugated C=C double bond and a reactive C-Cl bond in one molecule. The simultaneous ruthenium-catalyzed living radical polymerization of methyl acrylate and radical polyaddition of 3-butenyl 2-chloropropionate was achieved with Ru(Cp*)Cl(PPh{sub 3}){sub 2} to afford the controlled polymers, in which the homopolymer segments with the controlled chain length were connected by the ester linkage.

Aragonite precipitation by "proto-polyps" in coral cell cultures.

Directory of Open Access Journals (Sweden)

Tali Mass

Full Text Available The mechanisms of coral calcification at the molecular, cellular and tissue levels are poorly understood. In this study, we examine calcium carbonate precipitation using novel coral tissue cultures that aggregate to form "proto-polyps". Our goal is to establish an experimental system in which calcification is facilitated at the cellular level, while simultaneously allowing in vitro manipulations of the calcifying fluid. This novel coral culturing technique enables us to study the mechanisms of biomineralization and their implications for geochemical proxies. Viable cell cultures of the hermatypic, zooxanthellate coral, Stylophora pistillata, have been maintained for 6 to 8 weeks. Using an enriched seawater medium with aragonite saturation state similar to open ocean surface waters (Ω(arag~4, the primary cell cultures assemble into "proto-polyps" which form an extracellular organic matrix (ECM and precipitate aragonite crystals. These extracellular aragonite crystals, about 10 µm in length, are formed on the external face of the proto-polyps and are identified by their distinctive elongated crystallography and X-ray diffraction pattern. The precipitation of aragonite is independent of photosynthesis by the zooxanthellae, and does not occur in control experiments lacking coral cells or when the coral cells are poisoned with sodium azide. Our results demonstrate that proto-polyps, aggregated from primary coral tissue culture, function (from a biomineralization perspective similarly to whole corals. This approach provides a novel tool for investigating the biophysical mechanism of calcification in these organisms.

Polymer Catalysts Imprinted with Metal Ions as Biomimics of Metalloenzymes

Directory of Open Access Journals (Sweden)

Joanna Czulak

2013-01-01

Full Text Available This work presents the preparation and properties of molecularly imprinted polymers (MIPs with catalytic centers that mimic the active sites of metalloenzymes. The MIP synthesis was based on suspension polymerization of functional monomers (4-vinylpyridine and acrylonitrile with trimethylolpropane trimethacrylate as a crosslinker in the presence of transition metal ions and 4-methoxybenzyl alcohol as a template. Four metal ions have been chosen for imprinting from among the microelements that are the most essential in the native enzymes: Cu2+, Co2+, Mn2+, and Zn2+. To prepare catalysts, the required loading of metal ions was obtained during sorption process. The catalysts imprinted with Cu2+, Co2+, and Zn2+ were successfully used for hydroquinone oxidation in the presence of hydrogen peroxide. The Mn2+-imprinted catalyst showed no activity due to the insufficient metal loading. Cu2+ MIP showed the highest efficiency. In case of Cu- and Co-MIP catalysts, their activity was additionally increased by the use of surface imprinting technique.

Germline variants in Hamartomatous Polyposis Syndrome-associated genes from patients with one or few hamartomatous polyps

DEFF Research Database (Denmark)

Jelsig, Anne Marie; Brusgaard, Klaus; Hansen, Tine Plato

2016-01-01

OBJECTIVE: A subgroup of patients with hamartomatous polyps in the GI tract has a hereditary Hamartomatous Polyposis Syndrome with an increased risk of cancer. The distinction between patients with one or few polyps and patients with a syndrome can be difficult. A pathogenic germline mutation can...... significance of genetic variants can be difficult to interpret. A family history of polyps, cancer, or extraintestinal findings or a minimum of 3-5 polyps seems to be relevant information to include before genetic testing....

Reversible light-controlled conductance switching of azobenzene-based metal/polymer nanocomposites

International Nuclear Information System (INIS)

Pakula, Christina; Zaporojtchenko, Vladimir; Strunskus, Thomas; Faupel, Franz; Zargarani, Dordaneh; Herges, Rainer

2010-01-01

We present a new concept of light-controlled conductance switching based on metal/polymer nanocomposites with dissolved chromophores that do not have intrinsic current switching ability. Photoswitchable metal/PMMA nanocomposites were prepared by physical vapor deposition of Au and Pt clusters, respectively, onto spin-coated thin poly(methylmethacrylate) films doped with azo-dye molecules. High dye concentrations were achieved by functionalizing the azo groups with tails and branches, thus enhancing solubility. The composites show completely reversible optical switching of the absorption bands upon alternating irradiation with UV and blue light. We also demonstrate reversible light-controlled conductance switching. This is attributed to changes in the metal cluster separation upon isomerization based on model experiments where analogous conductance changes were induced by swelling of the composite films in organic vapors and by tensile stress.

Metallic microwires obtained as replicas of etched ion tracks in polymer matrixes: Microscopy and emission properties

International Nuclear Information System (INIS)

Zagorski, D.L.; Bedin, S.A.; Oleinikov, V.A.; Polyakov, N.B.; Rybalko, O.G.; Mchedlishvili, B.V.

2009-01-01

Specially prepared porous matrixes (with through and dead-end pores of cylindrical or conical forms) were used as the templates for making ensembles of microwires. The process of electrodeposition of metal (Cu) into these pores was investigated. AFM technique was used for studying the 'composite material' (metal microwires embedded into the polymer matrix). It was shown that the combination of different modes of AFM (tapping with phase-contrast mode, contact with lateral force mode) makes it possible to detect metal in the polymer matrix. Additional spread resistance mode in the contact regime allowed to measure the electrical conductivity of a single wire. The ensembles of free-standing microwires (metallic replicas of the pores obtained after removing of the polymer matrix) were used as the substrates (for deposition of the probe) for ion emission in the mass-spectrometer. It was shown that the intensity of formed ion beam increases with increasing of power of the laser pulse and with increasing of the mass of the probe. The intensity of mass-spectra signal on the power of laser pulse has a threshold character with saturation accompanied with the appearance of dimer ions. At the same time this intensity decreases with the increasing of the surface density of wires. The effect of degradation of wires during the laser pulse irradiation was found.

CT findings of the angiomatous polyp in the nasal cavity and paranasal sinus

Energy Technology Data Exchange (ETDEWEB)

Jang, Young Sim; Youm, Dong Ho; Lee, Myeong Sub; Kang, In Goo; Lee, Jun Ha; Sung, Ki Joon; Cho, Mee Yon; Yang, Suk Woo [Yonsei Univ. College of Medicine, Wonju (Korea, Republic of)

1999-06-01

To assess the characteristic CT findings of the angiomatous polyp. Five cases of pathologically-proven angiomatous polyp were retrospectively evaluated. All underwent CT scanning, but in only four cases were postcontrast CT scans obtained. In analysing CT findings we focused on adjacent bony change, and the extent and enhancement pattern of the mass. All but one case involved the maxillary sinus, showing thickening of the posterolateral wall and erosion or destruction of the medial wall. As for involvement of the anterior wall of this sinus, bony destruction was seen in one case, and thickening in three. In four cases the tumor involved the maxillary sinus and nasal cavity, and two cases showed nasopharyngeal extension. No case involved the pterygopalatine fossa, however. On contrast enhanced CT scans(n=4), all cases showed enhancement as strong as blood vessels, and a multiple focal punctate or tubular pattern. Angiomatous polyp tends to show bone thickening rather than bone destruction, not to involve the pterygopalatine fossa, and to reveal a strong punctate or tubular enhancement pattern. These findings may be helpful in the differential diagnosis of angiomatous polyp from other tumors such as maxillary cancer, angiofibroma and nasal polyp.

CT colonography: Diagnostic role of contrast enhancement of benign polyps and colorectal carcinoma

International Nuclear Information System (INIS)

Stoinova, V.; Nedevska, M.

2006-01-01

Full text: The aim of this study was to compare pre- and postcontrast CT attenuation values of benign colorectal polyps and carcinoma lesions detected by CT colonography, and to investigate whether contrast enhancement of these lesions can be potentially used for differentiation from residual fluid and feces. We retrospectively reviewed CT colonographic dataset of 120 patients. 35 benign polyps and 22 colorectal carcinomas were included in our study. All lesions were confirmed by colonoscopic biopsy or surgery. The difference in attenuation value between precontrast and postcontrast studies of polyps was statistically significant; the same was true for colorectal cancers. In the precontrast phase no statistically significant difference was observed between stool, polyps and cancers. The mean attenuation value of solid fecal residuals was 37 HU before and after contrast enhancement. Residual fluid do not take up contrast and the density does not change in the contrast-enhanced phase. The difference between postcontrast density of polyps and cancers with respect to density of stools and residual fluid was significant. The use of contrast medium could be helpful in CT colonography for discriminating polypoid benign lesions and colorectal cancer from fecal and fluid residuals

Two cases of benign polyps of the posterior urethra (ectopic prostatic tissue)

OpenAIRE

多田, 晃司; 山羽, 正義; 田村, 公一; 藤広, 茂; 河田, 幸道

1990-01-01

We report two cases of benign polyps of the posterior urethra. Their first symptoms were gross hematuria and urinary frequency. Both specimens obtained by transurethral resection were histologically identified as prostatic tissue. Discussion on benign polyps of the posterior urethra as ectopic prostatic tissue was done with review of literature.

Electroless formation of conductive polymer-metal nanostructured composites at boundary of two immiscible solvents. Morphology and properties

International Nuclear Information System (INIS)

Gniadek, Marianna; Donten, Mikolaj; Stojek, Zbigniew

2010-01-01

Formation of polypyrrole (PPy) with metallic inclusions was carried out at the interface between the aqueous phase containing an oxidizer and an organic solution of the monomer. A variety of the polymer-metal composites were obtained in the system. When the oxidizers were silver- and gold salts the obtained material contained from 4 to 9 at.% of metal. In the case of Ag + oxidant the structure of the metallic silver objects varied and included beads and ultra thin wires covered by polymer film, nanocrystals, micrometer cuboid monocrystals and microplates. Metallic gold practically appeared only in one structure-granules. The granules of Au incorporated into PPy were porous and made of very fine flat crystals of thickness in the nanometer range. The use of copper salts never led to the formation of metallic species in the composite. The influence of selected process parameters such as temperature and concentration of the reactants on the polymerization reaction was investigated. The composites with metallic nanoobjects were found to be better catalysts for the electrooxidation of ascorbic acids compared to pure polypyrrole. SEM, X-ray diffractometry, Raman spectroscopy and voltammetry were used in the investigation.

Electroless formation of conductive polymer-metal nanostructured composites at boundary of two immiscible solvents. Morphology and properties

Energy Technology Data Exchange (ETDEWEB)

Gniadek, Marianna [Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw (Poland); Donten, Mikolaj, E-mail: donten@chem.uw.edu.p [Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw (Poland); Stojek, Zbigniew, E-mail: stojek@chem.uw.edu.p [Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw (Poland)

2010-11-01

Formation of polypyrrole (PPy) with metallic inclusions was carried out at the interface between the aqueous phase containing an oxidizer and an organic solution of the monomer. A variety of the polymer-metal composites were obtained in the system. When the oxidizers were silver- and gold salts the obtained material contained from 4 to 9 at.% of metal. In the case of Ag{sup +} oxidant the structure of the metallic silver objects varied and included beads and ultra thin wires covered by polymer film, nanocrystals, micrometer cuboid monocrystals and microplates. Metallic gold practically appeared only in one structure-granules. The granules of Au incorporated into PPy were porous and made of very fine flat crystals of thickness in the nanometer range. The use of copper salts never led to the formation of metallic species in the composite. The influence of selected process parameters such as temperature and concentration of the reactants on the polymerization reaction was investigated. The composites with metallic nanoobjects were found to be better catalysts for the electrooxidation of ascorbic acids compared to pure polypyrrole. SEM, X-ray diffractometry, Raman spectroscopy and voltammetry were used in the investigation.

Reactivity of Cu with poly(tetrafluoroethylene) and poly(vinyl chloride): Effect of pre- and post-metallization modification on the metal/polymer interface

International Nuclear Information System (INIS)

Perry, C.C.; Torres, J.; Carlo, S.R.; Fairbrother, D. Howard

2002-01-01

The reactivity of Cu with poly(tetrafluoroethylene) (PTFE) and poly(vinylchloride) (PVC) during thermal evaporation, as well as the effect of pre- and post-metallization Ar + ion and x-ray mediated surface modification treatments on the metal/polymer interface, have been studied using in situ x-ray photoelectron spectroscopy (XPS) and ex situ atomic force microscopy (AFM). During thermal evaporation, copper was unreactive on PTFE but reacted with PVC to form CuCl. Pretreatment of PTFE or PVC surfaces by Ar + ion or x-ray irradiation did not modify the chemical reactivity of the polymer surface during subsequent Cu deposition, although significant morphological changes were observed on PTFE by AFM. In contrast, post-metallization modification of the Cu/PTFE interface by Ar + ion or x-ray irradiation lead to the production of CuF 2 , and increased the yield of CuCl in the Cu/PVC system. In either the Cu/PTFE or Cu/PVC systems, the maximum concentration of copper halide formed and dependence upon treatment time was found to be similar for either Ar + ion or x-ray irradiation post-metallization treatment strategies, suggesting a common reaction mechanism

Colonic polyp detection method from 3D abdominal CT images based on local intensity analysis

International Nuclear Information System (INIS)

Oda, M.; Nakada, Y.; Kitasaka, T.; Mori, K.; Suenaga, Y.; Takayama, T.; Takabatake, H.; Mori, M.; Natori, H.; Nawano, S.

2007-01-01

This paper presents a detection method of colonic polyps from 3D abdominal CT images based on local intensity analysis. Recently, virtual colonoscopy (VC) has widely received attention as a new colon diagnostic method. VC is considered as a less-invasive inspection method which reduces patient load. However, since the colon has many haustra and its shape is long and convoluted, a physician has to change the viewpoint and the viewing direction of the virtual camera of VC many times while diagnosis. Additionally, there is a risk to overlook lesions existing in blinded areas caused by haustra. This paper proposes an automated colonic polyp detection method from 3D abdominal CT images. Colonic polyps are located on the colonic wall. Their CT values are higher than those of colonic lumen regions and lower than those of fecal materials tagged by an X-ray opaque contrast agent. CT values inside polyps which exist outside the tagged fecal materials tend to gradually increase from outward to inward (blob-like structure). CT values inside polyps that exist inside the tagged fecal materials tend to gradually decrease from outward to inward (inv-blob-like structure). We employ the blob and the inv-blob structure enhancement filters based on the eigenvalues of the Hessian matrix to detect polyps using intensity characteristic of polyps. Connected components with low output values of the enhancement filter are eliminated in false positive reduction process. Small connected components are also eliminated. We applied the proposed method to 44 cases of abdominal CT images. Sensitivity for polyps of 6 mm or larger was 80% with 4.7 false positives per case. (orig.)

Prevalence of advanced adenomas in small and diminutive colon polyps using direct measurement of size.

Science.gov (United States)

Tsai, Franklin C; Strum, Williamson B

2011-08-01

Most studies reporting polyp size use visual estimates. Determining the prevalence of advanced histology based on direct measurement of polyp size may help guide the management of polyps found at optical colonoscopy (OC) and CT colonography (CTC). We designed a large, prospective study to assess the prevalence of advanced adenomas based on direct measurement of polyp size by a certified pathologists' assistant as reported in the pathology report. Patients between 40 and 89 years of age who presented for screening colonoscopy were included in our study. Advanced adenomas were defined as ≥10 mm or ≥25% villous features, high grade dysplasia or cancer. Polyps were divided by size into three groups: diminutive (≤5 mm), small (6-9 mm) and large (≥10 mm). If more than one adenoma was present, the most advanced was used for analysis. We evaluated 6,905 consecutive patients referred for colonoscopy between January 2005 and December 2006. Of the 4,967 who met the inclusion criteria, the mean age was 58.8 and consisted of 59% women. Overall, 930 (18.7%) had an adenoma; 248 (5%) were advanced adenomas including 8 (0.16%) cancers. Of 89 polyps≥10 mm, 76 (85%) had advanced histology; of 247 polyps 6-9 mm, 67 (27%) were advanced; of 1,025 polyps ≤5 mm, 105 (10%) were advanced. Thus, 172 of 248 (69%) patients with advanced adenomas had small or diminutive adenomas. Our data indicate the majority (69%) of advanced adenomas are advanced adenomas (10%). These findings may help guide the management of sub-centimeter colon polyps found by OC or CTC.

Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

Science.gov (United States)

Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

2016-01-01

In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

Metallic-like Wilson ratio in the polyaniline hydrochloride conducting polymer

International Nuclear Information System (INIS)

Limelette, P.; Schmaltz, B.; Tran Van, F.; Brault, D.

2015-01-01

We report on the calorimetric and magnetic properties of the polyaniline hydrochloride in order to discuss its metallicity. Both the specific heat and the magnetic susceptibility χ have been investigated as a function of temperature from 300 K down to 2 K. The measurements of the specific heat have allowed us to determine the electronic Sommerfeld coefficient γ and the temperature dependence of the susceptibility has revealed a Pauli-like component. By combining χ and γ, the dimensionless Wilson ratio R W ∝χ/γ demonstrates that the universal free electrons limit is reached above 100 K as a strong check of the metallicity of this conducting polymer. By removing the Pauli component from the measured susceptibility, the resulting contribution displays below 100 K a well-defined Curie-like component in agreement with a few percents of spins localized by disorder at low temperatures. These results are therefore consistent with an electronic itinerancy, namely, a metallic state even in the presence of disorder

Electromechanical characterization of individual micron-sized metal coated polymer particles

Energy Technology Data Exchange (ETDEWEB)

Bazilchuk, Molly; Kristiansen, Helge [Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim 7491 (Norway); Conpart AS, Skjetten 2013 (Norway); Pettersen, Sigurd Rolland; Zhang, Zhiliang; He, Jianying, E-mail: jianying.he@ntnu.no [Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim 7491 (Norway)

2016-06-28

Micron-sized polymer particles with nanoscale metal coatings are essential in conductive adhesives for electronics assembly. The particles function in a compressed state in the adhesives. The link between mechanical properties and electrical conductivity is thus of the utmost importance in the formation of good electrical contact. A custom flat punch set-up based on nanoindentation has been developed to simultaneously deform and electrically probe individual particles. The set-up has a sufficiently low internal resistance to allow the measurement of sub-Ohm contact resistances. Additionally, the set-up can capture mechanical failure of the particles. Combining this data yields a fundamental understanding of contact behavior. We demonstrate that this method can clearly distinguish between particles of different sizes, with different thicknesses of metal coating, and different metallization schemes. The technique provides good repeatability and physical insight into the behavior of these particles that can guide adhesive design and the optimization of bonding processes.

Electromechanical characterization of individual micron-sized metal coated polymer particles

International Nuclear Information System (INIS)

Bazilchuk, Molly; Kristiansen, Helge; Pettersen, Sigurd Rolland; Zhang, Zhiliang; He, Jianying

2016-01-01

Micron-sized polymer particles with nanoscale metal coatings are essential in conductive adhesives for electronics assembly. The particles function in a compressed state in the adhesives. The link between mechanical properties and electrical conductivity is thus of the utmost importance in the formation of good electrical contact. A custom flat punch set-up based on nanoindentation has been developed to simultaneously deform and electrically probe individual particles. The set-up has a sufficiently low internal resistance to allow the measurement of sub-Ohm contact resistances. Additionally, the set-up can capture mechanical failure of the particles. Combining this data yields a fundamental understanding of contact behavior. We demonstrate that this method can clearly distinguish between particles of different sizes, with different thicknesses of metal coating, and different metallization schemes. The technique provides good repeatability and physical insight into the behavior of these particles that can guide adhesive design and the optimization of bonding processes.

Prevalence of endometrial polyps and abnormal uterine bleeding in a Danish population aged 20-74 years

DEFF Research Database (Denmark)

Dreisler, E; Stampe Sorensen, S; Ibsen, P H

2009-01-01

OBJECTIVE: To estimate the prevalence of endometrial polyps and to investigate associated abnormal uterine bleeding in a Danish population aged 20-74 years. METHODS: This was a study of a random selection of women from the Danish Civil Registration System: 1660 women were invited of whom 686 were...... verified polyps were asymptomatic. In asymptomatic premenopausal women the prevalence of polyps was 7.6%, while it was 13% in asymptomatic postmenopausal women. AUB, in particular intermenstrual bleeding, was more frequent among women without polyps (38%). By ultrasound examination, submucosal myomas were...

Rectifying effect of heterojunctions between metals and doped conducting polymer nanostructure pellets

International Nuclear Information System (INIS)

Long Yunze; Yin Zhihua; Hui Wen; Chen Zhaojia; Wan Meixiang

2008-01-01

This paper reports that the Schottky junctions between low work function metals (e.g. Al and In) and doped semiconducting polymer pellets (e.g. polyaniline (PANI) microsphere pellet and polypyrrole (PPy) nanotube pellet) have been prepared and studied. Since Ag is a high work function metal which can make an ohmic contact with polymer, silver paste was used to fabricate the electrodes. The Al/PANI/Ag heterojunction shows an obvious rectifying effect as shown in I – V characteristic curves (rectifying ratio γ = 5 at ±6 V bias at room temperature). As compared to the Al/PANI/Ag, the heterojunction between In and PANI (In/PANI/Ag) exhibits a lower rectifying ratio γ = 1.6 at ±2 V bias at room temperature. In addition, rectifying effect was also observed in the heterojunctions Al/PPy/Ag (γ = 3.2 at ±1.6 V bias) and In/PPy/Ag (γ = 1.2 at ±3.0 V bias). The results were discussed in terms of thermoionic emission theory. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Metachronous colon polyps in younger versus older adults: a case-control study.

Science.gov (United States)

Nagpal, Sajan Jiv Singh; Mukhija, Dhruvika; Sanaka, Madhusudhan; Lopez, Rocio; Burke, Carol A

2018-03-01

The incidence of colorectal cancer in the United States has decreased substantially in individuals aged 50 and older. In contrast, it is increasing in young adults. The polyp characteristics on baseline and follow-up colonoscopy in young adults are not well characterized. We describe the polyp characteristics on baseline and follow-up colonoscopy in adults 1 polyp removed on colonoscopy followed by a postpolypectomy colonoscopy were eligible. The primary outcome was the occurrence of advanced neoplasia or HR polyp features on follow-up colonoscopy. Secondary endpoints included factors associated with metachronous advanced neoplasia in young adults. The occurrence of metachronous advanced neoplasia in young adults was compared with a cohort of patients aged 50 years and older. Included were 128 patients with a mean age of 34.9 years; 124 patients (97%) had adenomas and 7% had sessile serrated polyps (SSPs). Advanced neoplasia was seen in 35% of patients at baseline. The median follow-up time was 33.6 months. Metachronous advanced neoplasia was identified in 7% of patients on follow-up colonoscopy. Baseline factors associated with metachronous advanced neoplasia included the presence of an SSP (hazard ratio, 7.8; 95% CI, 1.09-56.3; P = .041) with a trend in those with advanced neoplasia (hazard ratio, 3.4; 95% confidence interval, .89-12.8; P = .072). The occurrence of metachronous advanced neoplasia did not differ between the young and older cohorts (7% vs 12.2%, P = .58); however, young adults were less likely to have HR polyp features on follow-up (8.6% vs 20.3%, P = .008). More than 1 in 3 adults <40 years old undergoing colonoscopy had advanced neoplasia on baseline colonoscopy. The occurrence of metachronous advanced neoplasia in young adults is similar to older adults and appears to be associated with the size, pathology, and number of baseline polyps. Our data suggest young polyp-bearing adults may undergo postpolypectomy colonoscopy at intervals

Hybrid nanocomposites based on conducting polymer and silicon nanowires for photovoltaic application

International Nuclear Information System (INIS)

Chehata, Nadia; Ltaief, Adnen; Ilahi, Bouraoui; Salem, Bassem; Bouazizi, Abdelaziz; Maaref, Hassen; Baron, Thierry

2014-01-01

Hybrid nanocomposites based on a nanoscale combination of organic and inorganic semiconductors are a promising way to enhance the performance of solar cells through a higher aspect ratio of the interface and the good processability of polymers. Nanocomposites are based on a heterojunction network between poly (2-methoxy-5-(2-ethyhexyl-oxy)-p-phenylenevinylene) (MEH-PPV) as an organic electron donor and silicon nanowires (SiNWs) as an inorganic electron acceptor. Nanowires (NWs) seem to be a promising material for this purpose, as they provide a large surface area for contact with the polymer and a designated conducting pathway whilst their volume is low. In this paper, silicon nanowires are introduced by mixing them into the polymer matrix. Hybrid nanocomposites films were deposited onto ITO substrate by spin coating method. Optical properties and photocurrent response were investigated. Charge transfer between the polymer and SiNWs has been demonstrated through photoluminescence measurements. The photocurrent density of ITO/MEH-PPV:SiNWs/Al structures have been obtained by J–V characteristics. The J sc value is about 0.39 µA/cm 2 . - Highlights: • SiNWs synthesis by Vapor–Liquid–Solid (VLS) mechanism. • SiNWs contribution to absorption spectra enhancement of MEH-PPV:SiNWs nanocomposites. • Decrease of PL intensity of MEH-PPV by addition of SiNWs. • Charge transfer process was taken place. • ITO/MEH-PPV:SiNWs/Al structure shows a photovoltaic effect, with a FF of 0.32

Printed metal back electrodes for R2R fabricated polymer solar cells studied using the LBIC technique

DEFF Research Database (Denmark)

Krebs, Frederik C; Søndergaard, Roar; Jørgensen, Mikkel

2011-01-01

The performance of printable metal back electrodes for polymer solar cells were investigated using light beam induced current (LBIC) mapping of the final solar cell device after preparation to identify the causes of poor performance. Three different types of silver based printable metal inks were...

Automatic Polyp Detection via A Novel Unified Bottom-up and Top-down Saliency Approach.

Science.gov (United States)

Yuan, Yixuan; Li, Dengwang; Meng, Max Q-H

2017-07-31

In this paper, we propose a novel automatic computer-aided method to detect polyps for colonoscopy videos. To find the perceptually and semantically meaningful salient polyp regions, we first segment images into multilevel superpixels. Each level corresponds to different sizes of superpixels. Rather than adopting hand-designed features to describe these superpixels in images, we employ sparse autoencoder (SAE) to learn discriminative features in an unsupervised way. Then a novel unified bottom-up and top-down saliency method is proposed to detect polyps. In the first stage, we propose a weak bottom-up (WBU) saliency map by fusing the contrast based saliency and object-center based saliency together. The contrast based saliency map highlights image parts that show different appearances compared with surrounding areas while the object-center based saliency map emphasizes the center of the salient object. In the second stage, a strong classifier with Multiple Kernel Boosting (MKB) is learned to calculate the strong top-down (STD) saliency map based on samples directly from the obtained multi-level WBU saliency maps. We finally integrate these two stage saliency maps from all levels together to highlight polyps. Experiment results achieve 0.818 recall for saliency calculation, validating the effectiveness of our method. Extensive experiments on public polyp datasets demonstrate that the proposed saliency algorithm performs favorably against state-of-the-art saliency methods to detect polyps.

Combining heterogeneous features for colonic polyp detection in CTC based on semi-definite programming

Science.gov (United States)

Wang, Shijun; Yao, Jianhua; Petrick, Nicholas A.; Summers, Ronald M.

2009-02-01

Colon cancer is the second leading cause of cancer-related deaths in the United States. Computed tomographic colonography (CTC) combined with a computer aided detection system provides a feasible combination for improving colonic polyps detection and increasing the use of CTC for colon cancer screening. To distinguish true polyps from false positives, various features extracted from polyp candidates have been proposed. Most of these features try to capture the shape information of polyp candidates or neighborhood knowledge about the surrounding structures (fold, colon wall, etc.). In this paper, we propose a new set of shape descriptors for polyp candidates based on statistical curvature information. These features, called histogram of curvature features, are rotation, translation and scale invariant and can be treated as complementing our existing feature set. Then in order to make full use of the traditional features (defined as group A) and the new features (group B) which are highly heterogeneous, we employed a multiple kernel learning method based on semi-definite programming to identify an optimized classification kernel based on the combined set of features. We did leave-one-patient-out test on a CTC dataset which contained scans from 50 patients (with 90 6-9mm polyp detections). Experimental results show that a support vector machine (SVM) based on the combined feature set and the semi-definite optimization kernel achieved higher FROC performance compared to SVMs using the two groups of features separately. At a false positive per patient rate of 7, the sensitivity on 6-9mm polyps using the combined features improved from 0.78 (Group A) and 0.73 (Group B) to 0.82 (p<=0.01).

Schottky diodes between Bi2S3 nanorods and metal nanoparticles in a polymer matrix as hybrid bulk-heterojunction solar cells

International Nuclear Information System (INIS)

Saha, Sudip K.; Pal, Amlan J.

2015-01-01

We report the use of metal-semiconductor Schottky junctions in a conjugated polymer matrix as solar cells. The Schottky diodes, which were formed between Bi 2 S 3 nanorods and gold nanoparticles, efficiently dissociated photogenerated excitons. The bulk-heterojunction (BHJ) devices based on such metal-semiconductor Schottky diodes in a polymer matrix therefore acted as an efficient solar cell as compared to the devices based on only the semiconductor nanorods in the polymer matrix or when gold nanoparticles were added separately to the BHJs. In the latter device, gold nanoparticles offered plasmonic enhancement due to an increased cross-section of optical absorption. We report growth and characteristics of the Schottky junctions formed through an intimate contact between Bi 2 S 3 nanorods and gold nanoparticles. We also report fabrication and characterization of BHJ solar cells based on such heterojunctions. We highlight the benefit of using metal-semiconductor Schottky diodes over only inorganic semiconductor nanorods or quantum dots in a polymer matrix in forming hybrid BHJ solar cells

CLINICAL, EPIDEMIOLOGIC, AND ENDOSCOPIC PROFILE IN CHILDREN AND ADOLESCENTS WITH COLONIC POLYPS IN TWO REFERENCE CENTERS

Directory of Open Access Journals (Sweden)

Denise O ANDRADE

2015-12-01

Full Text Available Background - The main goal of this paper is to investigate the frequency, clinical profile, and endoscopic findings of children and teenagers submitted to colonoscopies. Methods - Patients of below 18 years of age, diagnosed with polyps by means of colonoscopies at two reference centers of pediatric endoscopy were followed-up between 2002 and 2012. The clinical variables evaluated in this study included: gender, recommendation of colonoscopy, associated signs and symptoms, age of onset of symptoms, age at identification of the polyp, interval of time between the onset of symptoms and the endoscopic diagnosis of colonic polyps, and family history of intestinal polyposis and/or colorectal cancer. The characteristics of the polyps also included: number, morphological type, histology, and distribution. Polyposis syndromes were also investigated. Results - From the 233 patients submitted to colonoscopies, polyps were found in 74 (31.7% patients, with a median age of 6.6 years, of which 61% were male. Juvenile polyps were identified in 55 (74% patients, with 7 (9% characterized within the criteria for juvenile polyposis. Patients with intestinal polyposis syndromes were diagnosed in 35% of the patients. The most frequent clinical presentation was hematochezia. Abdominal pain with acute episodes of intestinal partial obstruction or intussusception with emergency laparotomy was observed in the majority of Peutz-Jeghers syndrome patients leading to an increased morbidity. Conclusions - Even though juvenile colonic polyps are the most frequent type of diagnosed polyps, the present study identified a significant level of children with polyposis syndromes (35%, associated with a higher morbidity of these individuals.

Preparation, characterization, magnetic and thermal studies of some chelate polymers of first series transition metal ions

International Nuclear Information System (INIS)

Ukey, Vaishali V.; Juneja, H.D.; Borkar, S.D.; Ghubde, R.S.; Naz, S.

2006-01-01

Azelaoyl-bis-hydroxamic acid used as bis ligand for the preparation of chelate polymers of Mn(II), Co(II), Ni(II) and Zn(II). These chelate polymers have been synthesized by refluxing the metal acetate and bis ligand as 1:1 stoichiometry. In the present work, structural determination of these newly synthesized chelate polymers has been studied on the basis of elemental analyses, infrared and reflectance spectral, magnetic and thermal studies. The decomposition temperature and the order of reaction have been determined by TGA analysis. On the basis of these studies, the Zn(II) chelate polymer has tetrahedral geometry, whereas Mn(II), Co(II) and Ni(II) chelate polymers have octahedral geometry and have the thermal stability in the order Ni(II) > Mn(II) > Zn(II) > Co(II)

Omalizumab is effective in allergic and nonallergic patients with nasal polyps and asthma

NARCIS (Netherlands)

Gevaert, Philippe; Calus, Lien; van Zele, Thibaut; Blomme, Katrien; de Ruyck, Natalie; Bauters, Wouter; Hellings, Peter; Brusselle, Guy; de Bacquer, Dirk; van Cauwenberge, Paul; Bachert, Claus

2013-01-01

Background: Adult patients with nasal polyps often have comorbid asthma, adding to the serious effect on the quality of life of these patients. Nasal polyps and asthma might represent a therapeutic challenge; inflammation in both diseases shares many features, such as airway eosinophilia, local IgE

Knife-assisted snare resection: a novel technique for resection of scarred polyps in the colon.

Science.gov (United States)

Chedgy, Fergus J Q; Bhattacharyya, Rupam; Kandiah, Kesavan; Longcroft-Wheaton, Gaius; Bhandari, Pradeep

2016-03-01

There have been significant advances in the management of complex colorectal polyps. Previous failed resection or polyp recurrence is associated with significant fibrosis, making endoscopic resection extremely challenging; the traditional approach to these lesions is surgery. The aim of this study was to evaluate the efficacy of a novel, knife-assisted snare resection (KAR) technique in the resection of scarred colonic polyps. This was a prospective cohort study of patients, in whom the KAR technique was used to resect scarred colonic polyps > 2  cm in size. Patients had previously undergone endoscopic mucosal resection (EMR) and developed recurrence, or EMR had been attempted but was aborted as a result of technical difficulty. A total of 42 patients underwent KAR of large (median 40  mm) scarred polyps. Surgery for benign disease was avoided in 38 of 41 patients (93 %). No life-threatening complications occurred. Recurrence was seen in six patients (16 %), five of whom underwent further endoscopic resection. The overall cure rate for KAR in complex scarred colonic polyps was 90 %. KAR of scarred colonic polyps by an expert endoscopist was an effective and safe technique with low recurrence rates. © Georg Thieme Verlag KG Stuttgart · New York.

Evaluation of synthetic water-soluble metal-binding polymers with ultrafiltration for selective concentration of americium and plutonium

International Nuclear Information System (INIS)

Smith, B.F.; Gibson, R.R.; Jarvinen, G.D.; Jones, M.M.; Lu, M.T.; Robison, T.W.; Schroeder, N.C.; Stalnaker, N.

1997-01-01

Routine counting methods and ICP-MS are unable to directly measure the new US Department of Energy (DOE) regulatory level for discharge waters containing alpha-emitting radionuclides of 30 pCi/L total alpha or the 0.05 pCi/L regulatory level for Pu or Am activity required for surface waters at the Rocky Flats site by the State of Colorado. This inability indicates the need to develop rapid, reliable, and robust analytical techniques for measuring actinide metal ions, particularly americium and plutonium. Selective separation or preconcentration techniques would aid in this effort. Water-soluble metal-binding polymers in combination with ultrafiltration are shown to be an effective method for selectively removing dilute actinide ions from acidic solutions of high ionic strength. The actinide-binding properties of commercially available water-soluble polymers and several polymers which have been reported in the literature were evaluated. The functional groups incorporated in the polymers were pyrrolidone, amine, oxime, and carboxylic, phosphonic, or sulfonic acid. The polymer containing phosphonic acid groups gave the best results with high distribution coefficients and concentration factors for 241 Am(III) and 238 Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4

Site-selective metallization of polymeric substrates by the hyperbranched polymer templates

International Nuclear Information System (INIS)

Li, Peiyuan; Yang, Fang; Li, Xiangcheng; He, Chunling; Su, Wei; Chen, Jinhao; Huo, Lini; Chen, Rui; Lu, Chensheng; Liang, Lifang

2013-01-01

We demonstrate a simple, cost-effective and universal technique for the fabrication of copper circuit pattern on flexible polymeric substrate. This method relies on a ternary polyethylenimine-poly(acrylic acid)-substrate film incorporating palladium catalysts, which are used as adhesive interlayers for the copper metallization of flexible polymeric substrates. We demonstrated the fabrication of patterned copper films on a variety of flexible polymers with minimum feature sizes of 200 μm. And the resulting copper circuit showed strong adhesion with underlying flexible polymeric substrates. The films were characterized by ATR FT-IR, contact angle, XPS, XRD, TEM and SEM. The direct patterning of metallic circuit on flexible polymeric substrate indicates great potential for the use in electronics industry.

Site-selective metallization of polymeric substrates by the hyperbranched polymer templates

Energy Technology Data Exchange (ETDEWEB)

Li, Peiyuan, E-mail: lipearpear@163.com [College of Pharmacy, Guangxi University of Chinese Medicine, Nanning 530001 (China); Yang, Fang [College of Chemistry and Life Science, Guangxi Teachers Education University, Nanning 530001 (China); Li, Xiangcheng [School of Computer, Electronics and Information, Guangxi University, Nanning 530001 (China); He, Chunling [College of Pharmacy, Guangxi University of Chinese Medicine, Nanning 530001 (China); Su, Wei, E-mail: suwmail@163.com [College of Chemistry and Life Science, Guangxi Teachers Education University, Nanning 530001 (China); Chen, Jinhao [College of Chemistry and Life Science, Guangxi Teachers Education University, Nanning 530001 (China); Huo, Lini; Chen, Rui; Lu, Chensheng [College of Pharmacy, Guangxi University of Chinese Medicine, Nanning 530001 (China); Liang, Lifang [College of Chemistry and Life Science, Guangxi Teachers Education University, Nanning 530001 (China)

2013-09-01

We demonstrate a simple, cost-effective and universal technique for the fabrication of copper circuit pattern on flexible polymeric substrate. This method relies on a ternary polyethylenimine-poly(acrylic acid)-substrate film incorporating palladium catalysts, which are used as adhesive interlayers for the copper metallization of flexible polymeric substrates. We demonstrated the fabrication of patterned copper films on a variety of flexible polymers with minimum feature sizes of 200 μm. And the resulting copper circuit showed strong adhesion with underlying flexible polymeric substrates. The films were characterized by ATR FT-IR, contact angle, XPS, XRD, TEM and SEM. The direct patterning of metallic circuit on flexible polymeric substrate indicates great potential for the use in electronics industry.

Role of Interchain Coupling in the Metallic State of Conducting Polymers

Science.gov (United States)

Kim, Nara; Lee, Byoung Hoon; Choi, Doowhan; Kim, Geunjin; Kim, Heejoo; Kim, Jae-Ryoung; Lee, Jongjin; Kahng, Yung Ho; Lee, Kwanghee

2012-09-01

We investigated the charge dynamics of the conductivity enhancement from 2 to 1000S/cm in poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) as induced by structural changes through the addition of a polar solvent and the following solvent bath treatment. Our results indicate that the addition of a polar solvent selectively enhanced the π-π coupling of the polymer chains, resulting in the reduction of disorder and tremendously increasing the charge carrier mobility, which yielded an insulator-to-metal transition. In contrast, the following solvent bath treatment selectively enhanced the intergrain coupling, which did not affect the disorder or the mobility but increased the charge carrier density. Therefore, we demonstrate that the conduction-character defining disorder in this conducting polymer system is determined by the extent of interchain coupling.

Next-generation narrow band imaging system for colonic polyp detection: a prospective multicenter randomized trial.

Science.gov (United States)

Horimatsu, Takahiro; Sano, Yasushi; Tanaka, Shinji; Kawamura, Takuji; Saito, Shoichi; Iwatate, Mineo; Oka, Shiro; Uno, Koji; Yoshimura, Kenichi; Ishikawa, Hideki; Muto, Manabu; Tajiri, Hisao

2015-07-01

Previous studies have yielded conflicting results on the colonic polyp detection rate with narrow-band imaging (NBI) compared with white-light imaging (WLI). We compared the mean number of colonic polyps detected per patient for NBI versus WLI using a next-generation NBI system (EVIS LUCERA ELITE; Olympus Medical Systems) used with standard-definition (SD) colonoscopy and wide-angle (WA) colonoscopy. this study is a 2 × 2 factorial, prospective, multicenter randomized controlled trial. this study was conducted at five academic centers in Japan. patients were allocated to one of four groups: (1) WLI with SD colonoscopy (H260AZI), (2) NBI with SD colonoscopy (H260AZI), (3) WLI with WA colonoscopy (CF-HQ290), and (4) NBI with WA colonoscopy (CF-HQ290). the mean numbers of polyps detected per patient were compared between the four groups: WLI with/without WA colonoscopy and NBI with/without WA colonoscopy. Of the 454 patients recruited, 431 patients were enrolled. The total numbers of polyps detected by WLI with SD, NBI with SD, WLI with WA, and NBI with WA were 164, 176, 188, and 241, respectively. The mean number of polyps detected per patient was significantly higher in the NBI group than in the WLI group (2.01 vs 1.56; P = 0.032). The rate was not higher in the WA group than in the SD group (1.97 vs 1.61; P = 0.089). Although WA colonoscopy did not improve the polyp detection, next-generation NBI colonoscopy represents a significant improvement in the detection of colonic polyps.

Nattokinase, profibrinolytic enzyme, effectively shrinks the nasal polyp tissue and decreases viscosity of mucus.

Science.gov (United States)

Takabayashi, Tetsuji; Imoto, Yoshimasa; Sakashita, Masafumi; Kato, Yukinori; Tokunaga, Takahiro; Yoshida, Kanako; Narita, Norihiko; Ishizuka, Tamotsu; Fujieda, Shigeharu

2017-10-01

Chronic rhinosinusitis with nasal polyps (CRSwNP) is often comorbid with asthma and resistant to therapeutic interventions. We recently reported that excessive fibrin deposition caused by impairment of fibrinolysis might play pivotal role in forming nasal polyp. Nattokinase (NK), a serine protease produced by Bacillus subtilis, has been reported to be a strong fibrinolytic enzyme. NK could be a promising drug candidate for use in the treatment of both CRSwNP and asthma. The objective of this study was to investigate the effects of NK on nasal polyp tissues from patients with CRSwNP. The nasal discharge from patients with CRSwNP and sputum from subjects with asthma were also used to investigate whether NK influences the viscosity of mucus. To examine the effects on NK on nasal polyp tissues, pieces of nasal polyps were incubated either with saline or NK (10-1000 FU/ml) at 37 °C for 24 h. We assessed the presence of fibrin in nasal polyp tissue incubated with NK by means of immunohistochemistry. To examine the effects of NK on nasal discharge and sputum from patients with CRSwNP and asthma, respectively, were incubated with NK solution at 37 °C for 1 h. NK effectively shrinks the nasal polyp tissue through fibrin degradation. We also found that the viscosity of the nasal discharge and sputum from patients with CRSwNP and asthma, respectively, was significantly reduced by incubation with NK solution. NK may be an effective alternative therapeutic option in patients with CRSwNP and comorbid asthma by causing fibrin degradation. Copyright © 2017 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

Specialist Endoscopists Are Associated with a Decreased Risk of Incomplete Polyp Resection During Endoscopic Mucosal Resection in the Colon.

Science.gov (United States)

Tavakkoli, Anna; Law, Ryan J; Bedi, Aarti O; Prabhu, Anoop; Hiatt, Tadd; Anderson, Michelle A; Wamsteker, Erik J; Elmunzer, B Joseph; Piraka, Cyrus R; Scheiman, James M; Elta, Grace H; Kwon, Richard S

2017-09-01

Endoscopic experience is known to correlate with outcomes of endoscopic mucosal resection (EMR), particularly complete resection of the polyp tissue. Whether specialist endoscopists can protect against incomplete polypectomy in the setting of known risk factors for incomplete resection (IR) is unknown. We aimed to characterize how specialist endoscopists may help to mitigate the risk of IR of large sessile polyps. This is a retrospective cohort study of patients who underwent EMR at the University of Michigan from January 1, 2006, to November 15, 2015. The primary outcome was endoscopist-reported polyp tissue remaining at the end of the initial EMR attempt. Specialist endoscopists were defined as endoscopists who receive tertiary referrals for difficult colonoscopy cases and completed at least 20 EMR colonic polyp resections over the study period. A total of 257 patients with 269 polyps were included in the study. IR occurred in 40 (16%) cases. IR was associated with polyp size ≥ 40 mm [adjusted odds ratio (aOR) 3.31, 95% confidence interval (CI) 1.38-7.93], flat/laterally spreading polyps (aOR 2.61, 95% CI 1.24-5.48), and difficulty lifting the polyp (aOR 11.0, 95% CI 2.66-45.3). A specialist endoscopist performing the initial EMR was protective against IR, even in the setting of risk factors for IR (aOR 0.13, 95% CI 0.04-0.41). IR is associated with polyp size ≥ 40 mm, flat and/or laterally spreading polyps, and difficulty lifting the polyp. A specialist endoscopist initiating the EMR was protective of IR.

Porphyrin coordination polymer nanospheres and nanorods

Science.gov (United States)

Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

2012-12-04

A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

Colonoscopic Polypectomy of Colorectal Polyps in Children Under General Anesthesia

Directory of Open Access Journals (Sweden)

Chien-Heng Lin

2009-02-01

Full Text Available In many countries, general anesthesia is not routinely used for colonoscopic polypectomy in children because of either feasibility or cost-effectiveness issues. However, we have been using general anesthesia for colonoscopic polypectomy in pediatric patients in our hospital for the past 5 years. The aim of this study was to evaluate the safety of the procedure and the degree of satisfaction that the patients' parents and endoscopists had with the use of general anesthesia. We retrospectively analyzed the results of colonoscopic polypectomies under general anesthesia in 18 patients performed between January 2001 and December 2005. The removed polyps were examined histologically and the patients were observed to assess complications during the first 24-hour postoperative period. The patients' parents' and endoscopists' satisfaction with the use of general anesthesia was surveyed after the procedure. In our patient group, there were 10 boys and eight girls. The mean age was 5.5 ± 3.4 years (range, 2–15 years. Seventeen of the 18 patients had rectal bleeding (mean duration, 3.7 months as the main symptom. There were 12 patients with juvenile polyps, four with hyperplastic polyps, one with juvenile polyposis and one with Peutz-Jeghers syndrome. The majority (70.6% of the polyps were located in the rectosigmoid colon. No significant complications related to colonoscopic polypectomy or anesthesia were observed. Satisfaction among parents and endoscopists ranged from good to excellent. General anesthesia is recommended for pediatric patients undergoing colonoscopic polypectomy.

Selective metallization of polymers using laser induced surface activation (LISA)—characterization and optimization of porous surface topography

DEFF Research Database (Denmark)

Zhang, Yang; Hansen, Hans Nørgaard; De Grave, Arnaud

2011-01-01

Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was perfor...

Urethral polyp in a 1-month-old child

Energy Technology Data Exchange (ETDEWEB)

Beluffi, Giampiero [Department of Radiodiagnosis, IRCCS Policlinico S. Matteo, Section of Paediatric Radiology, Piazzale Golgi, 2, I-27100, Pavia PV (Italy); Berton, Francesca; Gola, Giada [University of Pavia, IRCCS Policlinico S. Matteo, Institute of Radiology, Pavia (Italy); Chiari, Giorgio; Romano, Piero; Cassani, Ferdinando [IRCCS Policlinico S. Matteo, Division of Paediatric Surgery, Pavia (Italy)

2005-07-01

Urethral polyps are a rare finding in children, particularly in the very young. They are suspected by the presence of various clinical signs such as obstruction, voiding dysfunction and haematuria. There is an association with other urinary tract congenital anomalies. They are usually benign fibro-epithelial lesions with no tendency to recur and are treated by surgical ablation, fulguration or laser therapy. We report a 1-month-old boy with an antenatally diagnosed left ectopic pelvic kidney, postnatal urinary tract infection and no clinical signs of obstruction. Voiding cystourethrography to exclude vesico-ureteric reflux showed a trabeculated bladder and a mobile filling defect in the posterior urethra. Owing to its large size, cystotomy was necessary to remove the polyp successfully. (orig.)

Urethral polyp in a 1-month-old child

International Nuclear Information System (INIS)

Beluffi, Giampiero; Berton, Francesca; Gola, Giada; Chiari, Giorgio; Romano, Piero; Cassani, Ferdinando

2005-01-01

Urethral polyps are a rare finding in children, particularly in the very young. They are suspected by the presence of various clinical signs such as obstruction, voiding dysfunction and haematuria. There is an association with other urinary tract congenital anomalies. They are usually benign fibro-epithelial lesions with no tendency to recur and are treated by surgical ablation, fulguration or laser therapy. We report a 1-month-old boy with an antenatally diagnosed left ectopic pelvic kidney, postnatal urinary tract infection and no clinical signs of obstruction. Voiding cystourethrography to exclude vesico-ureteric reflux showed a trabeculated bladder and a mobile filling defect in the posterior urethra. Owing to its large size, cystotomy was necessary to remove the polyp successfully. (orig.)

Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

International Nuclear Information System (INIS)

Resta, V.; Quarta, G.; Farella, I.; Maruccio, L.; Cola, A.; Calcagnile, L.

2014-01-01

The implantation of 1 MeV metal ( 63 Cu + , 107 Ag + , 197 Au + ) and non-metal ( 4 He + , 12 C + ) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10 13 ions cm −2 , the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10 17 ions cm −2 , the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C 0x clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C 0x cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10 7 Ω/sq has been measured for implantation with metals at doses higher than 5 × 10 16 ions cm −2 , being 10 17 Ω/sq the corresponding sheet resistance for pristine PC

Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Resta, V., E-mail: vincenzo.resta@le.infn.it [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Quarta, G. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Farella, I. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Maruccio, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Cola, A. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Calcagnile, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy)

2014-07-15

The implantation of 1 MeV metal ({sup 63}Cu{sup +}, {sup 107}Ag{sup +}, {sup 197}Au{sup +}) and non-metal ({sup 4}He{sup +}, {sup 12}C{sup +}) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10{sup 13} ions cm{sup −2}, the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10{sup 17} ions cm{sup −2}, the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C{sub 0x} clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C{sub 0x} cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10{sup 7} Ω/sq has been measured for implantation with metals at doses higher than 5 × 10{sup 16} ions cm{sup −2}, being 10{sup 17} Ω/sq the corresponding sheet resistance for pristine PC.

Development of Silicate Polymers

DEFF Research Database (Denmark)

Søgaard, Erik Gydesen; Simonsen, Morten Enggrob

  The development of inorganic polymers is a new promising technology that may be used in many applications. The syntheses of inorganic polymers are normally carried out either by mixing an amorphous material for example silicium dioxide with a mineral base or dissolving metal oxids or metal...... hydroxide in acid and increase pH to saturation of the metal hydroxide. It is assumed that the syntheses of the inorganic polymer are carried out through polymerisation of oligomers (dimer, trimer) which provide the actual unit structures of the three dimensional macromolecular structure. In this work...

Fused filament 3D printing of ionic polymer-metal composites for soft robotics

Science.gov (United States)

Carrico, James D.; Leang, Kam K.

2017-04-01

Additive manufacturing techniques are used to create three-dimensional structures with complex shapes and features from polymer and/or metal materials. For example, fused filament three-dimensional (3D) printing utilizes non-electroactive polymers, such as acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), to build structures and components in a layer-by-layer fashion for a wide variety of applications. Presented here is a summary of recent work on a fused filament 3D-printing technique to create 3D ionic polymer-metal composite (IPMC) structures for applications in soft robotics. The 3D printing technique overcomes some of the limitations of existing manufacturing processes for creating IPMCs, such as limited shapes and sizes and time-consuming manufacturing steps. In the process described, first a precursor material (non-acid Nafion precursor resin) is extruded into a thermoplastic filament for 3D printing. Then, a custom-designed 3D printer is described that utilizes the precursor filament to manufacture custom-shaped structures. Finally, the 3D-printed samples are functionalized by hydrolyzing them in an aqueous solution of potassium hydroxide and dimethyl sulfoxide, followed by application of platinum electrodes. Presented are example 3D-printed single and multi-degree-of-freedom IPMC actuators and characterization results, as well as example soft-robotic devices to demonstrate the potential of this process.

Demographic And Histopathological Characteristics Of Colorectal Polyps: A Descriptive Study Based On Samples Obtained From Symptomatic Patients

Directory of Open Access Journals (Sweden)

Cekodhima Genta

2016-06-01

Full Text Available Colorectal polyps (CP are common among individuals older than 50 years. Some polyp types can precede colorectal cancer (CRC. This study aimed at describing histopathological characteristics of colorectal polyps in relation to age and gender among symptomatic patients referred for a colonoscopy examination during 2011-2014 in Tirana, Albania.

Management and diagnosis of gallbladder polyps: a systematic review.

Science.gov (United States)

Babu, Benoy I; Dennison, Ashley R; Garcea, Giuseppe

2015-05-01

Recommendation for management of gallbladder polyps (GBPs) >1 cm is cholecystectomy. No consensus exists on management of GBPs extraction was used to retrieve specified end points. Literature search yielded 43 manuscripts with a dataset of 11,685 patients with GBPs. M:F ratio was 1.3:1. Average age (range) was 49 years (32-83). Patients with malignant GBPs had an average (range) age of 58 (50-66) years with M:F ratio of 0.78:1. Cholesterol polyps constituted 60.5% of GBPs followed by adenomas (15.2%) and cancer (11.6%). Malignant GBPs ≥1 cm, 1 cm is appropriate. For GBPs 10 mm.

Anomalous temperature dependence of the current in a metal-oxide-polymer resistive switching diode

NARCIS (Netherlands)

Gomes, H.L.; Rocha, P.R.F.; Kiazadeh, A.; Leeuw, de D.M.; Meskers, S.C.J.

2011-01-01

Metal-oxide polymer diodes exhibit non-volatile resistive switching. The current–voltage characteristics have been studied as a function of temperature. The low-conductance state follows a thermally activated behaviour. The high-conductance state shows a multistep-like behaviour and below 300 K an

Chemical potential pinning due to equilibrium electron transfer at metal/C{sub 60}-doped polymer interfaces

Energy Technology Data Exchange (ETDEWEB)

Heller, C.M.; Campbell, I.H.; Smith, D.L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Barashkov, N.N.; Ferraris, J.P. [The University of Texas at Dallas, Richardson, Texas 75080 (United States)

1997-04-01

We report electroabsorption measurements of the built-in electrostatic potential in metal/C{sub 60}-doped polymer/metal structures to investigate chemical potential pinning due to equilibrium electron transfer from a metal contact to the electron acceptor energy level of C{sub 60} molecules in the polymer film. The built-in potentials of a series of structures employing thin films of both undoped and C{sub 60}-doped poly[2-methoxy, 5-(2{sup {prime}}-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were measured. For undoped MEH-PPV, which has an energy gap of about 2.4 eV, the maximum built-in potential is about 2.1 eV, whereas for C{sub 60}-doped MEH-PPV the maximum built-in potential decreases to 1.5 eV. Electron transfer to the C{sub 60} molecules close to the metal interface pins the chemical potential of the metal contact near the electron acceptor energy level of C{sub 60} and decreases the built-in potential of the structure. From the systematic dependence of the built-in potential on the metal work function we find that the electron acceptor energy level of C{sub 60} in MEH-PPV is about 1.7 eV above the hole polaron energy level of MEH-PPV. {copyright} {ital 1997 American Institute of Physics.}

Increased polyp detection using narrow band imaging compared with high resolution endoscopy in patients with hyperplastic polyposis syndrome

NARCIS (Netherlands)

Boparai, K. S.; van den Broek, F. J. C.; van Eeden, S.; Fockens, P.; Dekker, E.

2011-01-01

Hyperplastic polyposis syndrome (HPS) is associated with colorectal cancer and is characterized by multiple hyperplastic polyps, sessile serrated adenomas (SSAs) and adenomas. Narrow band imaging (NBI) may improve the detection of polyps in HPS. We aimed to compare polyp miss rates with NBI with

Study of Plant Cell Wall Polymers Affected by Metal Accumulation Using Stimulated Raman Scattering Microscopy

Energy Technology Data Exchange (ETDEWEB)

Ding, Shi-You [Harvard Univ., Cambridge, MA (United States)

2015-03-02

This project aims to employ newly-developed chemical imaging techniques to measure, in real-time, the concentration, dynamics and spatial distribution of plant cell wall polymers during biomass growth with inoculation of transgenic symbiotic fungi, and to explore a new pathway of delivering detoxified metal to plant apoplast using transgenic symbiotic fungi, which will enhance metal accumulation from soil, and potentially these metals may in turn be used as catalysts to improve the efficiency of biomass conversion to biofuels. The proposed new pathway of biomass production will: 1) benefit metal and radionuclide contaminant mobility in subsurface environments, and 2) potentially improve biomass production and process for bioenergy

Metal chloride-treated graphene oxide to produce high-performance polymer solar cells

Energy Technology Data Exchange (ETDEWEB)

Choi, Eun-Su; Noh, Yong-Jin; Kwon, Sung-Nam; Na, Seok-In, E-mail: nsi12@jbnu.ac.kr [Professional Graduate School of Flexible and Printable Electronics and Polymer Materials Fusion Research Center, Chonbuk National University, 664-14, Deokjin-dong, Deokjin-gu, Jeonju-si, Jeollabuk-do 561-756 (Korea, Republic of); Jeon, Ye-Jin [School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Kim, Seok-Soon, E-mail: sskim@kunsan.ac.kr [Department of Nano and Chemical Engineering, Kunsan National University, Kunsan, Jeollabuk-do 753-701 (Korea, Republic of); Kim, Tae-Wook [Soft Innovative Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, San 101, Eunha-ri, Bongdong-eup, Wanju-gun, Jeollabuk-do 565-905 (Korea, Republic of)

2015-07-13

We introduce a simple but effective graphene oxide (GO) modification with metal chloride treatments to produce high-performance polymer solar cells (PSCs). The role of various metal chlorides on GO and their effects on device performances of PSCs was investigated. X-ray photoelectron spectroscopy, ultraviolet photoemission spectroscopy, and current-voltage measurement studies demonstrated that metal chloride can induce a p-doping effect and increase the GO work-function, thus resulting in an improved built-in potential and interfacial resistance in PSCs. The resultant PSCs with metal chloride exhibited improved device efficiency than those with the neat GO. Furthermore, with the metal chloride-doped GO, we finally achieved an excellent PSC-efficiency of 6.58% and a very desirable device stability, which constitute a highly similar efficiency but much better PSC life-time to conventional device with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). This study could be a valuable way to produce various PEDOT:PSS alternatives and beneficial for producing high-performance and cost-efficient polymeric devices.

Prevalence of colorectal adenomatous polyps in patients with chronic obstructive pulmonary disease

Directory of Open Access Journals (Sweden)

Chun EM

2015-05-01

Full Text Available Eun Mi Chun, Seo Woo Kim, So Yeon Lim Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Republic of Korea Background: Colorectal adenomatous polyps are precancerous lesions of colorectal cancer. The aim of this study was to assess the prevalence of colorectal adenomatous polyps in chronic obstructive pulmonary disease (COPD patients and determine whether COPD is associated with colorectal malignant potential.Methods: Subjects who had undergone post-bronchodilator spirometry and colonoscopy and were 40 years or older were selected from the hospital database. COPD was defined as a spirometry in which the ratio of forced expiratory volume in 1 second (FEV1 and forced vital capacity (FVC is <0.7 in post-bronchodilator spirometry. The non-COPD group was matched for both age and sex, and were defined as having an FEV1, FVC, and FEV1/FVC ≥0.7 in spirometry. Finally, 333 patients were retrospectively reviewed; of this group, 82 patients had COPD.Results: Among the subjects, 201 patients (60% were nonsmokers, while 78 (23% were current smokers. The prevalence of colorectal adenomatous polyps was 39% (98/251 in the non-COPD group and 66% (54/82 in the COPD group. Among 54 patients with adenomatous polyps in the COPD group, 47 had tubular adenoma and seven had villous adenoma. Multiple logistic regression analyses revealed that only COPD patients whom matched to the criteria of COPD by pulmonary function test (odds ratio 2.1, 95% confidence interval: 1.1–3.8; P=0.019 were independently associated with colorectal malignant potential.Conclusion: The risk of colorectal malignant potential in the COPD group was higher than in the non-COPD group. We may suggest that COPD patients should consider regular colonoscopic evaluation to screen for premalignant colon polyps regardless of smoking. Keywords: COPD, colorectal adenomatous polyp, smoking, chronic obstructive pulmonary

Polymer-encapsulated metal nanoparticles: optical, structural, micro-analytical and hydrogenation studies of a composite material

International Nuclear Information System (INIS)

Scalzullo, Stefania; Mondal, Kartick; Deshmukh, Amit; Scurrell, Mike; Mallick, Kaushik; Witcomb, Mike

2008-01-01

A single-step synthesis route is described for the preparation of a metal-polymer composite in which palladium acetate and meta-amino benzoic acid were used as the precursors for palladium nanoparticles and poly(meta-amino benzoic acid) (PABA). The palladium nanoparticles were found to be uniformly dispersed and highly stabilized throughout the macromolecule matrix. The resultant composite material was characterized by means of different techniques, such as IR and Raman spectroscopy, which provided information regarding the chemical structure of the polymer, whereas electron microscopy images yielded information regarding the morphology of the composite material and the distribution of the metal particles in the composite material. The composite material was used as a catalyst for the ethylene hydrogenation reaction and showed catalytic activity at higher temperatures. TEM studies confirmed the changed environment of the nanoparticles at these temperatures

Confocal Endomicroscopy of Colorectal Polyps

Directory of Open Access Journals (Sweden)

Vivian M. Ussui

2012-01-01

Full Text Available Confocal laser endomicroscopy (CLE is one of several novel methods that provide real-time, high-resolution imaging at a micron scale via endoscopes. CLE has the potential to be a disruptive technology in that it can change the current algorithms that depend on biopsy to perform surveillance of high-risk conditions. Furthermore, it allows on-table decision making that has the potential to guide therapy in real time and reduce the need for repeated procedures. CLE and related technologies are often termed “virtual biopsy” as they simulate the images seen in traditional histology. However, the imaging of living tissue allows more than just pragmatic convenience; it also allows imaging of living tissue such as active capillary circulation, cellular death, and vascular and endothelial translocation, thus extending beyond what is capable in traditional biopsy. Immediate potential applications of CLE are to guide biopsy sampling in Barrett's esophagus and inflammatory bowel disease surveillance, evaluation of colorectal polyps, and intraductal imaging of the pancreas and bile duct. Data on these applications is rapidly emerging, and more is needed to clearly demonstrate the optimal applications of CLE. In this paper, we will focus on the role of CLE as applied to colorectal polyps detected during colonoscopy.

The Impact of Template Types on Polyeugenol to the Adsorption Selectivity of Ionic Imprinted Polymer (IIP) Fe Metal Ion

Science.gov (United States)

Djunaidi, M. C.; Haris, A.; Pardoyo; Rosdiana, K.

2018-04-01

The synthesis of IIP was carried out by variation of Fe(III) ion templates from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 compounds which then tested IIP selectivity to the Fe metal ions through adsorption process. Ionic Imprinted Polymer (IIP) is a method of printing metal ions bound in a polymer, subsequently released from the polymer matrix to produce a suitable imprint for the target ion. The purposes of this study were to produce IIP from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates, to know the effect of templates on adsorption selectivity of IIP involving imprint cavity, and to know the impact of metal competitor on the selectivity adsorption of IIP to the Fe metals. The results obtained showed that IIP synthesized by variations of Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates were successfully synthesized. The adsorption selectivity of Fe (III) metal ion in the Fe(NO3)3 template was greater than that of in the K3[Fe(CN)6] and NH4Fe(SO4)2 templates. The adsorption selectivity of Fe was greater on Fe-Cr compared to on Fe-Cd and Fe-Pb.

Nanocomposite metal/plasma polymer films prepared by means of gas aggregation cluster source

Energy Technology Data Exchange (ETDEWEB)

Polonskyi, O.; Solar, P.; Kylian, O.; Drabik, M.; Artemenko, A.; Kousal, J.; Hanus, J.; Pesicka, J.; Matolinova, I. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Kolibalova, E. [Tescan, Libusina trida 21, 632 00 Brno (Czech Republic); Slavinska, D. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Biederman, H., E-mail: bieder@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic)

2012-04-02

Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture.

One pot electrochemical synthesis of polymer/CNT/metal nanoparticles for fuel cell applications

Science.gov (United States)

Ventrapragada, Lakshman; Zhu, Jingyi; Karakaya, Mehmet; Podila, Ramakrishna; Rao, Apparao; Clemson Nanomaterials center Team

Carbon nanotubes (CNTs) have become a key player in the design of materials for energy applications. They gained their popularity in industrial and scientific research due to their unique properties like excellent conductivity, high surface area, etc. Here we used chemical vapor deposition (CVD) to synthesize two types of CNTs namely, helically coiled CNTs and vertically aligned CNTs. These CNTs were subsequently used to make composites with conducting polymers and metal nanoparticles. One pot electrochemical synthesis was designed to electropolymerize aniline, pyrrole etc. on the surface of the electrode with simultaneous deposition of platinum and gold metal nanoparticles, and CNTs in the polymer matrix. The as synthesized composite materials were characterized with scanning electron microscope for surface morphology and spectroscopic techniques like Raman, UV-Vis for functionality. These were used to study electrocatalytic oxidation of methanol and ethanol for alkaline fuel cell applications. Electrodes fabricated from these composites not only showed good kinetics but also exhibited excellent stability. Uniqueness of this composite lies in its simple two step synthesis and it doesn't involve any surfactants unlike conventional chemical synthesis routes.

Detection of colonic polyps in the elderly: Optimization of the single-contrast barium enema examination

International Nuclear Information System (INIS)

Gelfand, D.W.; Chen, Y.M.; Ott, D.J.; Munitz, H.A.

1986-01-01

Single-contrast studies account for 75% of barium enema examinations and are often performed in the elderly. By optimizing all factors, the following results were obtained: for polyps of less than 1 cm, 40 of 57 were detected (sensitivity, 70.2%); for polyps of 1 cm or larger, 33 of 35 were detected (sensitivity, 94%). Overall, 73 of 92 polyps were detected (sensitivity, 79.3%). These sensitivities result from meticulous preparation and the use of compression filming, low-density barium, moderate kilovoltages, high-resolution screens, remote control apparatus, and high-bandpass TV fluoroscopy. The authors conclude that an optimal single-contrast barium enema examination detects colonic polyps with a sensitivity approaching that of the double-contrast study and may be employed in elderly patients who cannot undergo the double-contrast study

The interfacial chemistry of metallized, oxide coated, and nanocomposite coated polymer films

Energy Technology Data Exchange (ETDEWEB)

Barker, C.P. [Durham Univ. (United Kingdom). Dept. of Chemistry; Kochem, K.H. [HOECHST Aktiengesellschaft, Werk Kalle/Albert, Geschaftsbereich H, Rheingaustrasse 190-196, D-65174 Wiesbaden (Germany); Revell, K.M. [CAMVAC (Europe) Ltd., Burrell Way, Thetford, Norfolk IP24 3QY (United Kingdom); Kelly, R.S.A. [CAMVAC (Europe) Ltd., Burrell Way, Thetford, Norfolk IP24 3QY (United Kingdom); Badyal, J.P.S. [Durham Univ. (United Kingdom). Dept. of Chemistry

1995-02-15

Aluminium, aluminium oxide, and aluminium/aluminium oxide nanocomposite coated polymer substrates have been characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, argon ion sputter depth profiling, and gas permeation measurements. A comparison of the similarities and differences between these coatings has provided a detailed insight into the physicochemical origins of gas barrier associated with metallized plastics. Keywords: Aluminium; Aluminium oxide; Coatings; X-ray photoelectron spectroscopy ((orig.))

The Fibroepithelial Polyp of the Urethra: A Rare Cause of Urinary Terention In Children

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Nihat Uluocak

2012-10-01

Full Text Available Benign fibroepithelial polyp of the prostatic urethra is a rare congenital lesion. It is most commonly diagnosed in the pediatric population and causes various urinary symptoms. In this case report, we presented a thirteen months old boy with a posterior urethral polyp who admitted to our clinic with complaints of obstructive urinary symptoms. An obstructing mass extending from bladder neck to prostatic urethra was seen in endoscopy. The lesion was completely removed by transure-thral resection. Pathological evaluation of the specimen revealed fibroepithelial polyp of the urethra. At postoperative follow up periods no complications of mic-turition at control examinations.

Characterisation of polymers, 1

CERN Document Server

Crompton, Roy

2008-01-01

This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

Impedance study of tea with added taste compounds using conducting polymer and metal electrodes.

Science.gov (United States)

Dhiman, Mopsy; Kapur, Pawan; Ganguli, Abhijit; Singla, Madan Lal

2012-09-01

In this study the sensing capabilities of a combination of metals and conducting polymer sensing/working electrodes for tea liquor prepared by addition of different compounds using an impedance mode in frequency range 1 Hz-100 KHz at 0.1 V potential has been carried out. Classification of six different tea liquor samples made by dissolving various compounds (black tea liquor + raw milk from milkman), (black tea liquor + sweetened clove syrup), (black tea liquor + sweetened ginger syrup), (black tea liquor + sweetened cardamom syrup), (black tea liquor + sweet chocolate syrup) and (black tea liquor + vanilla flavoured milk without sugar) using six different working electrodes in a multi electrode setup has been studied using impedance and further its PCA has been carried out. Working electrodes of Platinum (Pt), Gold (Au), Silver (Ag), Glassy Carbon (GC) and conducting polymer electrodes of Polyaniline (PANI) and Polypyrrole (PPY) grown on an ITO surface potentiostatically have been deployed in a three electrode set up. The impedance response of these tea liquor samples using number of working electrodes shows a decrease in the real and imaginary impedance values presented on nyquist plots depending upon the nature of the electrode and amount of dissolved salts present in compounds added to tea liquor/solution. The different sensing surfaces allowed a high cross-selectivity in response to the same analyte. From Principal Component Analysis (PCA) plots it was possible to classify tea liquor in 3-4 classes using conducting polymer electrodes; however tea liquors were well separated from the PCA plots employing the impedance data of both conducting polymer and metal electrodes.

Profluorescent PPV-Based Micellar System as a Versatile Probe for Bioimaging and Drug Delivery.

Science.gov (United States)

Zaquen, Neomy; Lu, Hongxu; Chang, Teddy; Mamdooh, Russel; Lutsen, Laurence; Vanderzande, Dirk; Stenzel, Martina; Junkers, Thomas

2016-12-12

Although micelles are commonly used for drug delivery purposes, their long-term fate is often unknown due to photobleaching of the fluorescent labels or the use of toxic materials. Here, we present a metal-free, nontoxic, nonbleaching, fluorescent micelle that can address these shortcomings. A simple, yet versatile, profluorescent micellar system, built from amphiphilic poly(p-phenylenevinylene) (PPV) block copolymers, for use in drug delivery applications is introduced. Polymer micelles made from PPV show excellent stability for up to 1 year and are successfully loaded with anticancer drugs (curcumin or doxorubicin) without requiring introduction of physical or chemical cross-links. The micelles are taken up efficiently by the cells, which triggers disassembly, releasing the encapsulated material. Disassembly of the micelles and drug release is conveniently monitored as fluorescence of the single polymer chains appear, which enables not only to monitor the release of the payload, but in principle also the fate of the polymer over longer periods of time.

Microfabrication of air core power inductors with metal-encapsulated polymer vias

International Nuclear Information System (INIS)

Kim, Jungkwun; Herrault, Florian; Yu, Xuehong; Kim, Minsoo; Shafer, Richard H; Allen, Mark G

2013-01-01

This paper reports three-dimensional (3-D) microfabricated toroidal inductors intended for power electronics applications. A key fabrication advance is the exploitation of thick metal encapsulation of polymer pillars to form a vertical via interconnections. The radial conductors of the toroidal inductor are formed by conventional plating-through-mold techniques, while the vertical windings (up to 650 µm in height) are formed by polymer cores with metal plated on their external surfaces. This encapsulated polymer approach not only significantly reduces the required plating time but also exploits the relative ease of fabricating high-aspect-ratio SU-8 pillars. To form the top radial conductors, non-photopatternable SU-8 is introduced as a thick sacrificial layer. Two toroidal inductor geometries were fabricated and tested. The first inductor had an inner diameter of 2 mm, an outer diameter of 6 mm, 25 turns and a vertical via height of 650 µm. The second inductor had an inner diameter of 4 mm, an outer diameter of 8 mm, 50 turns and a vertical via height of 650 µm. Both inductor geometries were successfully fabricated and characterized in the frequency range of 0.1−100 MHz. Characterization results of the 25- and 50-turn inductors showed an average inductance of 76 and 200 nH, a low frequency (0.1 MHz) resistance of 0.2 and 1 Ω and a quality factor of 35 and 24 at 100 MHz, respectively. Finite-element simulations of the inductors were performed and agreed with the measured results to within 8%. The turn-to-turn breakdown voltage was measured to be in excess of 800 V and currents as high as 0.5 A could be successfully carried by the inductor windings. (paper)

Single-step generation of metal-plasma polymer multicore@shell nanoparticles from the gas phase.

Science.gov (United States)

Solař, Pavel; Polonskyi, Oleksandr; Olbricht, Ansgar; Hinz, Alexander; Shelemin, Artem; Kylián, Ondřej; Choukourov, Andrei; Faupel, Franz; Biederman, Hynek

2017-08-17

Nanoparticles composed of multiple silver cores and a plasma polymer shell (multicore@shell) were prepared in a single step with a gas aggregation cluster source operating with Ar/hexamethyldisiloxane mixtures and optionally oxygen. The size distribution of the metal inclusions as well as the chemical composition and the thickness of the shells were found to be controlled by the composition of the working gas mixture. Shell matrices ranging from organosilicon plasma polymer to nearly stoichiometric SiO 2 were obtained. The method allows facile fabrication of multicore@shell nanoparticles with tailored functional properties, as demonstrated here with the optical response.

Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

LENUS (Irish Health Repository)

Keeling, Aoife N

2012-02-01

PURPOSE: To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS: IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS: Twenty-four polyps were detected in eighteen patients with CC (5 polyps >\\/=10mm, 4 polyps 6-9mm, 15 polyps <\\/=5mm). MRC was 66.7% (12\\/18) sensitive and 96.4% (27\\/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5\\/5) and 100% (19\\/19), respectively, for lesions greater than 10mm, 100% (4\\/4) and 100% (20\\/20) for lesions 6-9mm, and sensitivity of 20% (3\\/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9\\/9) and 100% (15\\/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION: MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps >\\/=6mm in size. Further studies are warranted.

Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

LENUS (Irish Health Repository)

Keeling, Aoife N

2010-12-03

PURPOSE: To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS: IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS: Twenty-four polyps were detected in eighteen patients with CC (5 polyps ≥10mm, 4 polyps 6-9mm, 15 polyps ≤5mm). MRC was 66.7% (12\\/18) sensitive and 96.4% (27\\/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5\\/5) and 100% (19\\/19), respectively, for lesions greater than 10mm, 100% (4\\/4) and 100% (20\\/20) for lesions 6-9mm, and sensitivity of 20% (3\\/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9\\/9) and 100% (15\\/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION: MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps ≥6mm in size. Further studies are warranted.

Detection of flat colorectal polyps at screening CT colonography in comparison with conventional polypoid lesions

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Sakamoto, Takashi; Urata, Joji [Diagnostic Imaging Center, Saiseikai Kumamoto Hospital, Kumamoto (Japan); Mitsuzaki, Katsuhiko; Matsuda, Katsuhiko; Kawakami, Megumi [Medical Examination Center, Saiseikai Kumamoto Hospital, Kumamoto (Japan); Utsunomiya, Daisuke; Yamamura, Sadahiro; Yamashita, Yasuyuki [Diagnostic Radiology, Faculty of Life Sciences, Kumamoto Univ., Kumamoto (Japan)], e-mail: utsunomi@kumamoto-u.ac.jp

2012-09-15

Background: Although the screening of small, flat polyps is clinically important, the role of CT colonography (CTC) screening in their detection has not been thoroughly investigated. Purpose: To evaluate the detection capability and usefulness of CTC in the screening of flat and polypoid lesions by comparing CTC with optic colonoscopy findings as the gold standard. Material and Methods: We evaluated the CTC detection capability for flat colorectal polyps with a flat surface and a height not exceeding 3 mm (n = 42) by comparing to conventional polypoid lesions (n = 418) according to the polyp diameter. Four types of reconstruction images including multiplanar reconstruction, volume rendering, virtual gross pathology, and virtual endoscopic images were used for visual analysis. We compared the abilities of the four reconstructions for polyp visualization. Results: Detection sensitivity for flat polyps was 31.3 %, 44.4 %, and 87.5 % for lesions measuring 2-3 mm, 4-5 mm, and {>=}6 mm, respectively; the corresponding sensitivity for polypoid lesions was 47.6 %, 79.0 %, and 91.7 %. The overall sensitivity for flat lesions (47.6%) was significantly lower than polypoid lesions (64.1%). Virtual endoscopic imaging showed best visualization among the four reconstructions. Colon cancers were detected in eight patients by optic colonoscopy, and CTC detected colon cancers in all eight patients. Conclusion: CTC using 64-row multidetector CT is useful for colon cancer screening to detect colorectal polyps while the detection of small, flat lesions is still challenging.

Foods and food groups associated with the incidence of colorectal polyps: the Adventist Health Study.

Science.gov (United States)

Tantamango, Yessenia M; Knutsen, Synnove F; Beeson, W Lawrence; Fraser, Gary; Sabate, Joan

2011-01-01

Colorectal cancer (CRC) is a leading cause of cancer death in the United States. The majority of CRC arise in adenomatous polyps and 25-35% of colon adenoma risk could be avoidable by modifying diet and lifestyle habits. We assessed the association between diet and the risk of self-reported physician-diagnosed colorectal polyps among 2,818 subjects who had undergone colonoscopy. Subjects participated in 2 cohort studies: the AHS-1 in 1976 and the AHS-2 from 2002-2005. Multivariate logistic regression analysis was used to estimate the period risk of incident cases of polyps; 441 cases of colorectal polyps were identified. Multivariate analysis adjusted by age, sex, body mass index, and education showed a protective association with higher frequency of consumption of cooked green vegetables (OR 1 time/d vs. Consumption of legumes at least 3 times/wk reduced the risk by 33% after adjusting for meat intake. Consumption of brown rice at least 1 time/wk reduced the risk by 40%. These associations showed a dose-response effect. High frequency of consumption of cooked green vegetables, dried fruit, legumes, and brown rice was associated with a decreased risk of colorectal polyps.

Polyp morphology: an interobserver evaluation for the Paris classification among international experts.

Science.gov (United States)

van Doorn, Sascha C; Hazewinkel, Y; East, James E; van Leerdam, Monique E; Rastogi, Amit; Pellisé, Maria; Sanduleanu-Dascalescu, Silvia; Bastiaansen, Barbara A J; Fockens, Paul; Dekker, Evelien

2015-01-01

The Paris classification is an international classification system for describing polyp morphology. Thus far, the validity and reproducibility of this classification have not been assessed. We aimed to determine the interobserver agreement for the Paris classification among seven Western expert endoscopists. A total of 85 short endoscopic video clips depicting polyps were created and assessed by seven expert endoscopists according to the Paris classification. After a digital training module, the same 85 polyps were assessed again. We calculated the interobserver agreement with a Fleiss kappa and as the proportion of pairwise agreement. The interobserver agreement of the Paris classification among seven experts was moderate with a Fleiss kappa of 0.42 and a mean pairwise agreement of 67%. The proportion of lesions assessed as "flat" by the experts ranged between 13 and 40% (Pagreement did not change (kappa 0.38, pairwise agreement 60%). Our study is the first to validate the Paris classification for polyp morphology. We demonstrated only a moderate interobserver agreement among international Western experts for this classification system. Our data suggest that, in its current version, the use of this classification system in daily practice is questionable and it is unsuitable for comparative endoscopic research. We therefore suggest introduction of a simplification of the classification system.

Polyp Detection, Characterization, and Management Using Narrow-Band Imaging with/without Magnification

Directory of Open Access Journals (Sweden)

Takahiro Utsumi

2015-11-01

Full Text Available Narrow-band imaging (NBI is a new imaging technology that was developed in 2006 and has since spread worldwide. Because of its convenience, NBI has been replacing the role of chromoendoscopy. Here we review the efficacy of NBI with/without magnification for detection, characterization, and management of colorectal polyps, and future perspectives for the technology, including education. Recent studies have shown that the next-generation NBI system can detect significantly more colonic polyps than white light imaging, suggesting that NBI may become the modality of choice from the beginning of screening. The capillary pattern revealed by NBI, and the NBI International Colorectal Endoscopic classification are helpful for prediction of histology and for estimating the depth of invasion of colorectal cancer. However, NBI with magnifying colonoscopy is not superior to magnifying chromoendoscopy for estimation of invasion depth. Currently, therefore, chromoendoscopy should also be performed additionally if deep submucosal invasive cancer is suspected. If endoscopists become able to accurately estimate colorectal polyp pathology using NBI, this will allow adenomatous polyps to be resected and discarded; thus, reducing both the risk of polypectomy and costs. In order to achieve this goal, a suitable system for education and training in in vivo diagnostics will be necessary.

Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen.

Science.gov (United States)

Taylor, Stuart A; Halligan, Steve; Bartram, Clive I; Morgan, Paul R; Talbot, Ian C; Fry, Nicola; Saunders, Brian P; Khosraviani, Kirosh; Atkin, Wendy

2003-10-01

To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon. Copyright RSNA, 2003

Clinical evaluation of endoscopic trimodal imaging for the detection and differentiation of colonic polyps.

Science.gov (United States)

van den Broek, Frank J C; Fockens, Paul; Van Eeden, Susanne; Kara, Mohammed A; Hardwick, James C H; Reitsma, Johannes B; Dekker, Evelien

2009-03-01

Endoscopic trimodal imaging (ETMI) incorporates high-resolution endoscopy (HRE) and autofluorescence imaging (AFI) for adenoma detection, and narrow-band imaging (NBI) for differentiation of adenomas from nonneoplastic polyps. The aim of this study was to compare AFI with HRE for adenoma detection and to assess the diagnostic accuracy of NBI for differentiation of polyps. This was a randomized trial of tandem colonoscopies. The study was performed at the Academic Medical Center in Amsterdam. One hundred patients underwent colonoscopy with ETMI. Each colonic segment was examined twice for polyps, once with HRE and once with AFI, in random order per patient. All detected polyps were assessed with NBI for pit pattern and with AFI for color, and subsequently removed. Histopathology served as the gold standard for diagnosis. The main outcome measures of this study were adenoma miss-rates of AFI and HRE, and diagnostic accuracy of NBI and AFI for differentiating adenomas from nonneoplastic polyps. Among 50 patients examined with AFI first, 32 adenomas were detected initially. Subsequent inspection with HRE identified 8 additional adenomas. Among 50 patients examined with HRE first, 35 adenomas were detected initially. Successive AFI yielded 14 additional adenomas. The adenoma miss-rates of AFI and HRE therefore were 20% and 29%, respectively (P = .351). The sensitivity, specificity, and overall accuracy of NBI for differentiation were 90%, 70%, and 79%, respectively; corresponding figures for AFI were 99%, 35%, and 63%, respectively. The overall adenoma miss-rate was 25%; AFI did not significantly reduce the adenoma miss-rate compared with HRE. Both NBI and AFI had a disappointing diagnostic accuracy for polyp differentiation, although AFI had a high sensitivity.

Hydrogen bonding as the origin of the switching behavior in dithiolated phenylene-vinylene oligomers

KAUST Repository

Obodo, Tobechukwu Joshua

2013-08-29

We investigate theoretically the switching behavior of a dithiolated phenylene-vinylene oligomer sandwiched between Au(111) electrodes using self-interaction corrected density-functional theory combined with the nonequilibrium Green\\'s-function method for quantum transport. The molecule presents a configurational bistability, which can be exploited in constructing molecular memories, switches, and sensors. We find that protonation of the terminating thiol groups is at the origin of the change in conductance. H bonding at the thiol group weakens the S-Au bond and reduces by about one order of magnitude the transmission coefficient at the Fermi level, and thus the linear response conductance. Furthermore, protonation downshifts in energy the position of the highest occupied molecular orbital, so that the current of the protonated species is lower than that of the unprotonated one along the entire bias range investigated, from −1.5 to 1.5 V. A second protonation at the opposite thiol group has only minor effects and no further drastic reduction in transmission takes place. Our results allow us to re-interpret the experimental data originally attributing the conductance reduction to H dissociation.

Charge transport through conducting organic poly(2-methoxy-5- (2-ethylhexyloxy)-1, 4-phenylenevinylene)

International Nuclear Information System (INIS)

Kumar, Pankaj; Misra, Aparna; Kamalasanan, M N; Jain, S C; Kumar, Vikram

2007-01-01

Current-voltage (J-V) characteristics of poly(2-methoxy-5- (2-ethyhexyloxy)-1, 4-phenylenevinylene)(MEH-PPV) have been studied in the hole-only devices ITO/PEDOT : PSS/MEH-PPV/Au, as a function of temperature from 300 to 98 K. Hole conduction in MEH-PPV has been well explained by an exponential trap-controlled drift model. In a considerable range of applied voltages, current obeys the power law J ∼ V l+1 , where l = T c /T and T c is the characteristic temperature of the exponential trap distribution. Assuming the effective density of states N ν = 2.7 x 10 18 cm -3 , the holes trap density (H b ) and characteristic temperature (T c ) have been calculated to be 1 x 10 18 cm -3 and 550 K, respectively. As the voltage further increases current deviates and becomes smaller than J ∼ V l+1 . At low temperatures and sufficiently high-applied voltages, current follows the V 2 law. At higher temperatures slopes less than 2 of the log J-log V plots have been observed. The possible reasons for this behaviour are mentioned

Registration of central paths and colonic polyps between supine and prone scans in computed tomography colonography: Pilot study

International Nuclear Information System (INIS)

Li Ping; Napel, Sandy; Acar, Burak; Paik, David S.; Jeffrey, R. Brooke Jr.; Beaulieu, Christopher F.

2004-01-01

Computed tomography colonography (CTC) is a minimally invasive method that allows the evaluation of the colon wall from CT sections of the abdomen/pelvis. The primary goal of CTC is to detect colonic polyps, precursors to colorectal cancer. Because imperfect cleansing and distension can cause portions of the colon wall to be collapsed, covered with water, and/or covered with retained stool, patients are scanned in both prone and supine positions. We believe that both reading efficiency and computer aided detection (CAD) of CTC images can be improved by accurate registration of data from the supine and prone positions. We developed a two-stage approach that first registers the colonic central paths using a heuristic and automated algorithm and then matches polyps or polyp candidates (CAD hits) by a statistical approach. We evaluated the registration algorithm on 24 patient cases. After path registration, the mean misalignment distance between prone and supine identical anatomic landmarks was reduced from 47.08 to 12.66 mm, a 73% improvement. The polyp registration algorithm was specifically evaluated using eight patient cases for which radiologists identified polyps separately for both supine and prone data sets, and then manually registered corresponding pairs. The algorithm correctly matched 78% of these pairs without user input. The algorithm was also applied to the 30 highest-scoring CAD hits in the prone and supine scans and showed a success rate of 50% in automatically registering corresponding polyp pairs. Finally, we computed the average number of CAD hits that need to be manually compared in order to find the correct matches among the top 30 CAD hits. With polyp registration, the average number of comparisons was 1.78 per polyp, as opposed to 4.28 comparisons without polyp registration

Metastatic Carcinoma Occurring in a Gastric Hyperplastic Polyp Mimicking Primary Gastric Cancer: The First Reported Case

Directory of Open Access Journals (Sweden)

Gabriel M. Groisman

2014-01-01

Full Text Available Hyperplastic polyps of the stomach are regarded as benign. However, in rare cases they may contain incipient primary carcinomas. To our knowledge, breast carcinoma metastatic to a gastric hyperplastic polyp has not yet been reported. We describe the case of a 69-year-old woman to whom a gastric polyp was endoscopically excised. The patient had previously undergone a right mastectomy for mixed, invasive ductal and lobular carcinoma 5 years earlier. Histological sections from the gastric lesion showed typical features of hyperplastic polyp with foci of poorly differentiated adenocarcinoma including signet ring cells infiltrating the lamina propria. The histologic findings were consistent with a primary gastric cancer. However, the carcinoma cells were immunopositive for estrogen and progesterone receptors and GATA3 and negative for CDX2, Hep Par 1, and MUC5AC. E-cadherin showed membranous reactivity in some of the carcinoma cells while in others it was negative. Accordingly, metastatic mixed, lobular and ductal breast carcinoma was diagnosed. We conclude that metastatic adenocarcinoma mimicking primary gastric cancer can be rarely encountered in hyperplastic gastric polyps.

Computer-assisted detection of colonic polyps with CT colonography using neural networks and binary classification trees

International Nuclear Information System (INIS)

Jerebko, Anna K.; Summers, Ronald M.; Malley, James D.; Franaszek, Marek; Johnson, C. Daniel

2003-01-01

Detection of colonic polyps in CT colonography is problematic due to complexities of polyp shape and the surface of the normal colon. Published results indicate the feasibility of computer-aided detection of polyps but better classifiers are needed to improve specificity. In this paper we compare the classification results of two approaches: neural networks and recursive binary trees. As our starting point we collect surface geometry information from three-dimensional reconstruction of the colon, followed by a filter based on selected variables such as region density, Gaussian and average curvature and sphericity. The filter returns sites that are candidate polyps, based on earlier work using detection thresholds, to which the neural nets or the binary trees are applied. A data set of 39 polyps from 3 to 25 mm in size was used in our investigation. For both neural net and binary trees we use tenfold cross-validation to better estimate the true error rates. The backpropagation neural net with one hidden layer trained with Levenberg-Marquardt algorithm achieved the best results: sensitivity 90% and specificity 95% with 16 false positives per study

Effects of Surgery on the Phonation Threshold Pressure in Patients With Vocal Fold Polyps

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Tyng-Guey Wang

2010-01-01

Conclusion: Laryngomicrosurgery can lower PTP in patients with vocal fold polyps and improve the ease of phonation. PTP is one of the objective measurements for assessing the effects of surgery in patients with vocal fold polyps. Use of an accelerometer to detect vocal fold vibration improved the measurement of PTP.

A General Model of Sensitized Luminescence in Lanthanide-Based Coordination Polymers and Metal-Organic Framework Materials.

Science.gov (United States)

Einkauf, Jeffrey D; Clark, Jessica M; Paulive, Alec; Tanner, Garrett P; de Lill, Daniel T

2017-05-15

Luminescent lanthanides containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed on these compounds, the lack of a meaningful understanding of the luminescence in lanthanide coordination polymers remains a significant challenge toward functional design. Currently, the study of these compounds is based on the antenna effect as derived from molecular systems, where organic antennae are used to facilitate lanthanide-centered luminescence. This molecular-based approach does not take into account the unique features of extended network solids, particularly the formation of band structure. While guidelines for the antenna effect are well established, they require modification before being applied to coordination polymers. A series of nine coordination polymers with varying topologies and organic linkers were studied to investigate the accuracy of the antenna effect in coordination polymer systems. By comparing a molecular-based approach to a band-based one, it was determined that the band structure that occurs in aggregated organic solids needs to be considered when evaluating the luminescence of lanthanide coordination polymers.

The CIMP Phenotype in BRAF Mutant Serrated Polyps from a Prospective Colonoscopy Patient Cohort

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Winnie C. Fernando

2014-01-01

Full Text Available Colorectal cancers arising via the serrated pathway are often associated with BRAF V600E mutation, CpG island methylator phenotype (CIMP, and microsatellite instability. Previous studies have shown a strong association between BRAF V600E mutation and serrated polyps. This study aims to evaluate CIMP status of all the serrated polyp subtypes and its association with functionally important genes such as MLH1, p16, and IGFBP7. CIMP status and methylation were evaluated using the real-time based MethyLight assay in 154 serrated polyps and 63 conventional adenomas. Results showed that CIMP-high serrated polyps were strongly associated with BRAF mutation and proximal colon. CIMP-high was uncommon in conventional adenomas (1.59%, occurred in 8.25% of hyperplastic polyps (HPs, and became common in sessile serrated adenomas (SSAs (51.43%. MLH1 methylation was mainly observed in the proximal colon and was significantly associated with BRAF mutation and CIMP-high. The number of samples methylated for p16 and IGFBP7 was the highest in SSAs. The methylation panel we used to detect CIMP is highly specific for CIMP-high cancers. With this panel, we demonstrate that CIMP-high is much more common in SSAs than HPs. This suggests that CIMP-high correlates with increased risk of malignant transformation which was also observed in methylation of functionally important genes.

The CIMP Phenotype in BRAF Mutant Serrated Polyps from a Prospective Colonoscopy Patient Cohort.

Science.gov (United States)

Fernando, Winnie C; Miranda, Mariska S; Worthley, Daniel L; Togashi, Kazutomo; Watters, Dianne J; Leggett, Barbara A; Spring, Kevin J

2014-01-01

Colorectal cancers arising via the serrated pathway are often associated with BRAF V600E mutation, CpG island methylator phenotype (CIMP), and microsatellite instability. Previous studies have shown a strong association between BRAF V600E mutation and serrated polyps. This study aims to evaluate CIMP status of all the serrated polyp subtypes and its association with functionally important genes such as MLH1, p16, and IGFBP7. CIMP status and methylation were evaluated using the real-time based MethyLight assay in 154 serrated polyps and 63 conventional adenomas. Results showed that CIMP-high serrated polyps were strongly associated with BRAF mutation and proximal colon. CIMP-high was uncommon in conventional adenomas (1.59%), occurred in 8.25% of hyperplastic polyps (HPs), and became common in sessile serrated adenomas (SSAs) (51.43%). MLH1 methylation was mainly observed in the proximal colon and was significantly associated with BRAF mutation and CIMP-high. The number of samples methylated for p16 and IGFBP7 was the highest in SSAs. The methylation panel we used to detect CIMP is highly specific for CIMP-high cancers. With this panel, we demonstrate that CIMP-high is much more common in SSAs than HPs. This suggests that CIMP-high correlates with increased risk of malignant transformation which was also observed in methylation of functionally important genes.

Poly-P storage by natural biofilms in streams with varying biogeochemistry

Science.gov (United States)

Carrick, H. J.

2015-12-01

Anthropogenic inputs of nitrogen (N) and phosphorus (P) have increased in many watersheds throughout the world; these inputs have been linked to the eutrophication of inland and coastal waters worldwide. We selected and surveyed 20, third-order streams that supported a range of water column biogeochemical conditions (conductivity, nutrient concentrations) located in the mid-Atlantic region, USA. Biofilm biomass, algal taxonomic composition, and nutrient stoichiometry (C, N, P, and poly-P) were measured at all stream sites. Pulse-amplitude modulation fluorometry (PAM) was used to estimate photosynthetic parameters for stream biofilms (e.g., alpha, Pmax), while microbiology techniques were used to verify poly-P storage by pro- and eukaryotic components of the biofilm (e.g., epi-fluorescent staining). As anticipated, chlorophyll ranged over 2 orders of magnitude among the streams (range 10-1,000 mg/m2). Biofilm chlorophyll and algal biovolume levels increased with water column nutrient contents, while the C:P ratio within the biofilm decreased. Both pro and eukaryotic organisms were present in resident biofilms and actively stored intracellular poly-P. Finally, the rate of photosynthetic within the biofilms appeared to be driven the nutritional condition of the biofilms; pmax and alpha values increased with significantly with stream biofilm poly-P content (r2 = 0.35 and 0.44, respectively). These results indicated that where nutrients are plentiful, biofilms P storage is favored, and this is likely a key regulator of stream biofilm biomass and productivity.

Tailoring of the morphology and chemical composition of thin organosilane microwave plasma polymer layers on metal substrates

Energy Technology Data Exchange (ETDEWEB)

Grundmeier, G.; Thiemann, P.; Carpentier, J.; Shirtcliffe, N.; Stratmann, M

2004-01-01

The growth of thin microwave organosilicon plasma polymers on model zinc surfaces was investigated as a function of the film thickness and the oxygen partial pressure during film deposition. The evolution of the topology of the film was studied by atomic force microscopy (AFM). The nano- and micro-roughness was investigated at the inner and the outer surfaces of the plasma polymers. A special etching procedure was developed to reveal the underside of the plasma polymer and thereby its inner surface. Rough films contained voids at the interface, which reduced the polymer/metal contact area. The increase in oxygen partial pressure led to a smoother film growth with a perfect imitation of the substrate topography at the interface. The chemical structure of the films was determined by infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). ToF-SIMS at the outer and the inner surface of the plasma polymers showed that the density of methylsilyl groups increases in the outer surface layer of the plasma polymer and depends on the oxygen partial pressure. The chemical composition of the films could be altered to pure SiO{sub 2} without changing the morphology by using oxygen-plasma post-treatment. This was proved by means of IRRAS and AFM. Chemistry and topology of the films were correlated with the apparent water contact angle. It was found that a linear relationship exists between the nanoscopic roughness of the plasma polymer and the static contact angle of water. Superposition of a nanoscopic roughness of the metal surface and the nanoscopic roughness of methylsilyl-rich films led to ultra-hydrophobic films with water contact angles up to 160 deg.

Gallbladder Polyps: An Ambiguous Cause of Biliary Colic

African Journals Online (AJOL)

However, ultrasonography revealed multiple hyperechoic mass lesions protruding in the gallbladder lumen suggestive of gallbladder polyps [Figure 1], largest one measured 8.2 mm [Figure 2]. Subsequently, the patient underwent conventional 4-port laparoscopic cholecystectomy. Histopathology revealed the benign ...

The prevalence of high dysplastic colonic adenomatous polyps in a 3 year endoscopic retrospective study from a single clinical center

Directory of Open Access Journals (Sweden)

Alexandru C. Septimiu

2017-04-01

Full Text Available Introduction: Many colon neoplastic tumors come from the malignancy of adenomatous polyps (70%-90% that were not timely diagnosed in order to be resected. Materials and Methods: We conducted a retrospective study regarding the incidence of adenomatous polyps during 1.000 consecutive colonoscopies performed in our Upper and Lower Digestive Endoscopy Laboratory during a three-year period. Results: During these colonoscopies, some targeted polyps were biopsied or completely removed and the samples had been sent to a complete anatomopathological examination. Taking into consideration the results, the polyps were classified after the histological type and the form of dysplasia, in order to determine the polyp forms that present a high risk of malignancy. Conclusion: Given the rather high frequency of malignant polyps discovered during our study, we highly recommend colonoscopy as a method of choice for routine monitoring of selected cases.

The Assessment of the Colo-rectal Polyps in Order to the New Diagnostic and Therapeutic Strategies

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Raluca Diac Andreea

2015-09-01

Full Text Available Objective. Assessment of the histological and endoscopic features of the colo-rectal polyps is requered for the application of the new diagnostic and therapeutical strategies in the managment of the diminutive polyps.

Drug Combo Decreases Colorectal Polyps in People with FAP

Science.gov (United States)

In people with familial adenomatous polyposis, or FAP, a combination treatment of erlotinib (Tarceva) and sulindac (Aflodac) decreased the number of precancerous colorectal polyps, according to recently published clinical trial results.

Automated image-based colon cleansing for laxative-free CT colonography computer-aided polyp detection

International Nuclear Information System (INIS)

Linguraru, Marius George; Panjwani, Neil; Fletcher, Joel G.; Summer, Ronald M.

2011-01-01

Purpose: To evaluate the performance of a computer-aided detection (CAD) system for detecting colonic polyps at noncathartic computed tomography colonography (CTC) in conjunction with an automated image-based colon cleansing algorithm. Methods: An automated colon cleansing algorithm was designed to detect and subtract tagged-stool, accounting for heterogeneity and poor tagging, to be used in conjunction with a colon CAD system. The method is locally adaptive and combines intensity, shape, and texture analysis with probabilistic optimization. CTC data from cathartic-free bowel preparation were acquired for testing and training the parameters. Patients underwent various colonic preparations with barium or Gastroview in divided doses over 48 h before scanning. No laxatives were administered and no dietary modifications were required. Cases were selected from a polyp-enriched cohort and included scans in which at least 90% of the solid stool was visually estimated to be tagged and each colonic segment was distended in either the prone or supine view. The CAD system was run comparatively with and without the stool subtraction algorithm. Results: The dataset comprised 38 CTC scans from prone and/or supine scans of 19 patients containing 44 polyps larger than 10 mm (22 unique polyps, if matched between prone and supine scans). The results are robust on fine details around folds, thin-stool linings on the colonic wall, near polyps and in large fluid/stool pools. The sensitivity of the CAD system is 70.5% per polyp at a rate of 5.75 false positives/scan without using the stool subtraction module. This detection improved significantly (p = 0.009) after automated colon cleansing on cathartic-free data to 86.4% true positive rate at 5.75 false positives/scan. Conclusions: An automated image-based colon cleansing algorithm designed to overcome the challenges of the noncathartic colon significantly improves the sensitivity of colon CAD by approximately 15%.

Most bowel cancer symptoms do not indicate colorectal cancer and polyps: a systematic review

Directory of Open Access Journals (Sweden)

Chan Siew F

2011-05-01

Full Text Available Abstract Background Bowel symptoms are often considered an indication to perform colonoscopy to identify or rule out colorectal cancer or precancerous polyps. Investigation of bowel symptoms for this purpose is recommended by numerous clinical guidelines. However, the evidence for this practice is unclear. The objective of this study is to systematically review the evidence about the association between bowel symptoms and colorectal cancer or polyps. Methods We searched the literature extensively up to December 2008, using MEDLINE and EMBASE and following references. For inclusion in the review, papers from cross sectional, case control and cohort studies had to provide a 2×2 table of symptoms by diagnosis (colorectal cancer or polyps or sufficient data from which that table could be constructed. The search procedure, quality appraisal, and data extraction was done twice, with disagreements resolved with another reviewer. Summary ROC analysis was used to assess the diagnostic performance of symptoms to detect colorectal cancer and polyps. Results Colorectal cancer was associated with rectal bleeding (AUC 0.66; LR+ 1.9; LR- 0.7 and weight loss (AUC 0.67, LR+ 2.5, LR- 0.9. Neither of these symptoms was associated with the presence of polyps. There was no significant association of colorectal cancer or polyps with change in bowel habit, constipation, diarrhoea or abdominal pain. Neither the clinical setting (primary or specialist care nor study type was associated with accuracy. Most studies had methodological flaws. There was no consistency in the way symptoms were elicited or interpreted in the studies. Conclusions Current evidence suggests that the common practice of performing colonoscopies to identify cancers in people with bowel symptoms is warranted only for rectal bleeding and the general symptom of weight loss. Bodies preparing guidelines for clinicians and consumers to improve early detection of colorectal cancer need to take into

A direct metal transfer method for cross-bar type polymer non-volatile memory applications

International Nuclear Information System (INIS)

Kim, Tae-Wook; Lee, Kyeongmi; Oh, Seung-Hwan; Wang, Gunuk; Kim, Dong-Yu; Jung, Gun-Young; Lee, Takhee

2008-01-01

Polymer non-volatile memory devices in 8 x 8 array cross-bar architecture were fabricated by a non-aqueous direct metal transfer (DMT) method using a two-step thermal treatment. Top electrodes with a linewidth of 2 μm were transferred onto the polymer layer by the DMT method. The switching behaviour of memory devices fabricated by the DMT method was very similar to that of devices fabricated by the conventional shadow mask method. The devices fabricated using the DMT method showed three orders of magnitude of on/off ratio with stable resistance switching, demonstrating that the DMT method can be a simple process to fabricate organic memory array devices

Specific features of laser selective sintering of loose powder layers of metal-polymer type

International Nuclear Information System (INIS)

Tolochko, N.K.; Sobolenko, N.V.; Mozzharov, S.E.; Yadrojtsev, I.A.

1996-01-01

Experimental study was carried out into laser sintering of metal and polymer powder mixtures containing 75 vol.% of nickel base alloy (spherical particles 60-70 μm in diameter) and 25 vol.% of PEP-219 polymer (angular isometric particles 50-100 μm in size). The powder mixture was deposited on a stainless steel substrate and heated by continuous laser beam directed normally to powder layer. Geometrical and structural parameters of single and multilayer sintered products are shown to depend on both laser processing conditions and heat transfer. Some recommendations are given aimed at manufacturing articles of required shape, surface properties and material strength. 6 refs.; 4 figs

Invasive adenocarcinoma arising from a mixed hyperplastic/adenomatous polyp and synchronous transverse colon cancer.

Science.gov (United States)

Chen, Chuang-Wei; Hsiao, Koung-Hong; Yue, Chung-Tai; Wang, Chia-Chi

2013-08-28

An admixture of hyperplastic and adenomatous components within the same polyp is unusual. Adenocarcinoma arising from a mixed hyperplastic/adenomatous polyp (MHAP) occurs even more rarely. We report the first case of a 59-year-old male who presented with invasive adenocarcinoma originating from a MHAP at a sigmoid colon and synchronous transverse colon cancer.

Invasive adenocarcinoma arising from a mixed hyperplastic/adenomatous polyp and synchronous transverse colon cancer

OpenAIRE

Chen, Chuang-Wei; Hsiao, Koung-Hong; Yue, Chung-Tai; Wang, Chia-Chi

2013-01-01

An admixture of hyperplastic and adenomatous components within the same polyp is unusual. Adenocarcinoma arising from a mixed hyperplastic/adenomatous polyp (MHAP) occurs even more rarely. We report the first case of a 59-year-old male who presented with invasive adenocarcinoma originating from a MHAP at a sigmoid colon and synchronous transverse colon cancer.

Deformation Recording Process In Polymer-Metal Bilayers And Its Use For Optical Storage

Science.gov (United States)

Cornet, Jean A.

1983-11-01

A non-antireflective polymer-metal bilayer structure, encapsulated inside a closed cons-truction/is used for digital data storage in the Thomson-CSF Gigadisc. In this paper, a simple model is presented for microdeformation recording in the medium. This model enables a good understanding of the readout signal as a function of the recording power and leads to some practical consequences. Useful polymers and metallic layers are identified and the disc performance is reported. It is shown that recording using laser diodes can be performed at bit rate up to 14 Mbits.s-1 with a laser power of 7 mW at the disc entry face, in case of a 1200 rpm disc speed. Moreover a working range of 4 mW, as defined by a 3 dB attenuation, is demonstrated. Discs from pilot production exhibit raw bit error rates at the level of 2.10-5. For usual environmental conditions, the disc behaviour is compatible with shelf-and archival life at scale of 10 years. Finally, the processes for both layers deposition and disc construction are easy and cost effective. It is concluded that Giaadisc can successfully enter today the market place.

Coordination Polymers and Metal Organic Frameworks Derived from 1,2,4-Triazole Amino Acid Linkers

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Yann Garcia

2011-10-01

Full Text Available The perceptible appearance of biomolecules as prospective building blocks in the architecture of coordination polymers (CPs and metal-organic frameworks (MOFs are redolent of their inclusion in the synthon/tecton library of reticular chemistry. In this frame, for the first time a synthetic strategy has been established for amine derivatization in amino acids into 1,2,4-triazoles. A set of novel 1,2,4-triazole derivatized amino acids were introduced as superlative precursors in the design of 1D coordination polymers, 2D chiral helicates and 3D metal-organic frameworks. Applications associated with these compounds are diverse and include gas adsorption-porosity partitioning, soft sacrificial matrix for morphology and phase selective cadmium oxide synthesis, FeII spin crossover materials, zinc-b-lactamases inhibitors, logistics for generation of chiral/non-centrosymmetric networks; and thus led to a foundation of a new family of functional CPs and MOFs that are reviewed in this invited contribution.

Polyp prevalence at colonoscopy among Nigerians: A prospective ...

African Journals Online (AJOL)

Polyp prevalence at colonoscopy among Nigerians: A prospective observational study. ... Materials and Methods: This is a prospective study of all colonoscopy examinations performed at the endoscopy unit of our hospital from January, 2007 to December 2013. The patient demographics, indications for colonoscopy, ...

Micromechanics of Amorphous Metal/Polymer Hybrid Structures with 3D Cellular Architectures: Size Effects, Buckling Behavior, and Energy Absorption Capability.

Science.gov (United States)

Mieszala, Maxime; Hasegawa, Madoka; Guillonneau, Gaylord; Bauer, Jens; Raghavan, Rejin; Frantz, Cédric; Kraft, Oliver; Mischler, Stefano; Michler, Johann; Philippe, Laetitia

2017-02-01

By designing advantageous cellular geometries and combining the material size effects at the nanometer scale, lightweight hybrid microarchitectured materials with tailored structural properties are achieved. Prior studies reported the mechanical properties of high strength cellular ceramic composites, obtained by atomic layer deposition. However, few studies have examined the properties of similar structures with metal coatings. To determine the mechanical performance of polymer cellular structures reinforced with a metal coating, 3D laser lithography and electroless deposition of an amorphous layer of nickel-boron (NiB) is used for the first time to produce metal/polymer hybrid structures. In this work, the mechanical response of microarchitectured structures is investigated with an emphasis on the effects of the architecture and the amorphous NiB thickness on their deformation mechanisms and energy absorption capability. Microcompression experiments show an enhancement of the mechanical properties with the NiB thickness, suggesting that the deformation mechanism and the buckling behavior are controlled by the brittle-to-ductile transition in the NiB layer. In addition, the energy absorption properties demonstrate the possibility of tuning the energy absorption efficiency with adequate designs. These findings suggest that microarchitectured metal/polymer hybrid structures are effective in producing materials with unique property combinations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Association of meat intake and meat-derived mutagen exposure with the risk of colorectal polyps by histologic type

Science.gov (United States)

Fu, Zhenming; Shrubsole, Martha J.; Smalley, Walter E.; Wu, Huiyun; Chen, Zhi; Shyr, Yu; Ness, Reid M.; Zheng, Wei

2011-01-01

Background The association of meat intake and meat-derived mutagens with colorectal tumor risk remains unclear. We evaluated this hypothesis in a large colonoscopy-based case-control study. Methods Included in the study were 2,543 polyp patients [(1,881 with adenomas, and 622 with hyperplastic polyp (HPP)] and 3,764 polyp-free controls. Surveys obtained information about meat intake by cooking methods and doneness levels plus other suspected or known risk factors for colorectal tumors. Unconditional logistic regression was used to derive odds ratios (ORs) after adjusting for potential confounders. Results High intake of red meat and processed meat (P-trend meat cooked using high-temperature cooking methods (P-trend ≤ 0.01), was associated with an elevated risk for colorectal polyps. A significant positive association between exposures to meat-derived heterocyclic amines and risk of polyps was found for both adenomas and hyperplastic polyps. Furthermore, the positive association with red-meat intake and heterocyclic amine exposure was stronger for multiple adenomas than single adenoma and serrated than non-serrated adenomas. Conclusion This study supports a role for red meat and meat-derived mutagen exposure in the development of colorectal tumor. PMID:21803984

Diagnostic accuracy of transabdominal high-resolution US for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with EUS.

Science.gov (United States)

Lee, Jeong Sub; Kim, Jung Hoon; Kim, Yong Jae; Ryu, Ji Kon; Kim, Yong-Tae; Lee, Jae Young; Han, Joon Koo

2017-07-01

To compare the diagnostic accuracy of transabdominal high-resolution ultrasound (HRUS) for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with endoscopic ultrasound (EUS) and pathology. Among 125 patients who underwent both HRUS and EUS, we included 29 pathologically proven cancers (T1 = 7, T2 = 19, T3 = 3) including 15 polypoid cancers and 50 surgically proven polyps (neoplastic = 30, non-neoplastic = 20). We reviewed formal reports and assessed the accuracy of HRUS and EUS for diagnosing cancer as well as the differential diagnosis of neoplastic polyps. Statistical analyses were performed using chi-square tests. The sensitivity, specificity, PPV, and NPV for gallbladder cancer were 82.7 %, 44.4 %, 82.7 %, and 44 % using HRUS and 86.2 %, 22.2 %, 78.1 %, and 33.3 % using EUS. HRUS and EUS correctly diagnosed the stage in 13 and 12 patients. The sensitivity, specificity, PPV, and NPV for neoplastic polyps were 80 %, 80 %, 86 %, and 73 % using HRUS and 73 %, 85 %, 88 %, and 69 % using EUS. Single polyps (8/20 vs. 21/30), larger (1.0 ± 0.28 cm vs. 1.9 ± 0.85 cm) polyps, and older age (52.5 ± 13.2 vs. 66.1 ± 10.3 years) were common in neoplastic polyps (p diagnostic accuracy for GB cancer compared with EUS. • HRUS and EUS showed similar diagnostic accuracy for differentiating neoplastic polyps. • Single, larger polyps and older age were common in neoplastic polyps. • HRUS is less invasive compared with EUS.

A role for the epidermal growth factor receptor signaling in development of intestinal serrated polyps in mice and humans.

Science.gov (United States)

Bongers, Gerold; Muniz, Luciana R; Pacer, Michelle E; Iuga, Alina C; Thirunarayanan, Nanthakumar; Slinger, Erik; Smit, Martine J; Reddy, E Premkumar; Mayer, Lloyd; Furtado, Glaucia C; Harpaz, Noam; Lira, Sergio A

2012-09-01

Epithelial cancers can be initiated by activating mutations in components of the mitogen-activated protein kinase signaling pathway such as v-raf murine sarcoma viral oncogene homolog B1 (BRAF), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), or epidermal growth factor receptor (EGFR). Human intestinal serrated polyps are a heterogeneous group of benign lesions, but some progress to colorectal cancer. Tumors that arise from these polyps frequently contain activating mutations in BRAF or KRAS, but little is known about the role of EGFR activation in their development. Polyp samples were obtained from adults during screening colonoscopies at Mount Sinai Hospital in New York. We measured levels of EGFR protein and phosphorylation in human serrated polyps by immunohistochemical and immunoblot analyses. We generated transgenic mice that express the ligand for EGFR, Heparin-binding EGF-like growth factor (HB-EGF), in the intestine. EGFR and the extracellular-regulated kinases (ERK)1/2 were phosphorylated in serrated areas of human hyperplastic polyps (HPPs), sessile serrated adenomas, and traditional serrated adenomas. EGFR and ERK1/2 were phosphorylated in the absence of KRAS or BRAF activating mutations in a subset of HPP. Transgenic expression of the EGFR ligand HB-EGF in the intestines of mice promoted development of small cecal serrated polyps. Mice that expressed a combination of HB-EGF and US28 (a constitutively active, G-protein-coupled receptor that increases processing of HB-EGF from the membrane) rapidly developed large cecal serrated polyps. These polyps were similar to HPPs and had increased phosphorylation of EGFR and ERK1/2 within the serrated epithelium. Administration of pharmacologic inhibitors of EGFR or MAPK to these transgenic mice significantly reduced polyp development. Activation of EGFR signaling in the intestine of mice promotes development of serrated polyps. EGFR signaling also is activated in human HPPs, sessile serrated adenomas

Computer-aided detection of colorectal polyps: can it improve sensitivity of less-experienced readers? Preliminary findings.

Science.gov (United States)

Baker, Mark E; Bogoni, Luca; Obuchowski, Nancy A; Dass, Chandra; Kendzierski, Renee M; Remer, Erick M; Einstein, David M; Cathier, Pascal; Jerebko, Anna; Lakare, Sarang; Blum, Andrew; Caroline, Dina F; Macari, Michael

2007-10-01

To determine whether computer-aided detection (CAD) applied to computed tomographic (CT) colonography can help improve sensitivity of polyp detection by less-experienced radiologist readers, with colonoscopy or consensus used as the reference standard. The release of the CT colonographic studies was approved by the individual institutional review boards of each institution. Institutions from the United States were HIPAA compliant. Written informed consent was waived at all institutions. The CT colonographic studies in 30 patients from six institutions were collected; 24 images depicted at least one confirmed polyp 6 mm or larger (39 total polyps) and six depicted no polyps. By using an investigational software package, seven less-experienced readers from two institutions evaluated the CT colonographic images and marked or scored polyps by using a five-point scale before and after CAD. The time needed to interpret the CT colonographic findings without CAD and then to re-evaluate them with CAD was recorded. For each reader, the McNemar test, adjusted for clustered data, was used to compare sensitivities for readers without and with CAD; a Wilcoxon signed-rank test was used to analyze the number of false-positive results per patient. The average sensitivity of the seven readers for polyp detection was significantly improved with CAD-from 0.810 to 0.908 (P=.0152). The number of false-positive results per patient without and with CAD increased from 0.70 to 0.96 (95% confidence interval for the increase: -0.39, 0.91). The mean total time for the readings was 17 minutes 54 seconds; for interpretation of CT colonographic findings alone, the mean time was 14 minutes 16 seconds; and for review of CAD findings, the mean time was 3 minutes 38 seconds. Results of this feasibility study suggest that CAD for CT colonography significantly improves per-polyp detection for less-experienced readers. Copyright (c) RSNA, 2007.

Ectopic lymphoid tissues support local immunoglobulin production in patients with chronic rhinosinusitis with nasal polyps.

Science.gov (United States)

Song, Jia; Wang, Hai; Zhang, Ya-Na; Cao, Ping-Ping; Liao, Bo; Wang, Zhe-Zheng; Shi, Li-Li; Yao, Yin; Zhai, Guan-Ting; Wang, Zhi-Chao; Liu, Li-Meng; Zeng, Ming; Lu, Xiang; Wang, Heng; Yang, Xiang-Ping; Yu, Di; Bachert, Claus; Liu, Zheng

2018-03-01

The contribution of ectopic lymphoid tissues (eLTs) to local immunoglobulin hyperproduction in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) is unclear. We sought to explore the cellular basis, formation mechanisms, and function of eLTs in patients with CRSwNP. We graded lymphoid aggregations in sinonasal mucosa and histologically studied their structures. The expression of lymphorganogenic factors and molecules required for immunoglobulin production was measured by using real-time PCR, and their localization was analyzed by means of immunohistochemistry and immunofluorescence. The phenotype of follicular helper T cells was analyzed by performing flow cytometry. Immunoglobulin levels were quantified by using the Bio-Plex assay or ImmunoCAP system. Nasal tissue explants were challenged ex vivo with Dermatophagoides pteronyssinus group 1 (Der p 1), and the expression of Iε-Cμ and Iε-Cγ circle transcripts was detected by using seminested PCR. Increased formation of eLTs with germinal center-like structures was discovered in patients with eosinophilic (20.69%) and noneosinophilic (17.31%) CRSwNP compared with that in patients with chronic rhinosinusitis without nasal polyps (5.66%) and control subjects (3.70%). The presence of eLTs was associated with increased expression of lymphorganogenic and inflammatory chemokines and cytokines, as well as their receptors. The expression of molecules required for immunoglobulin production, generation of follicular helper T cells, and production of IgE in eosinophilic polyps and IgG and IgA in both eosinophilic and noneosinophilic polyps were predominantly upregulated in patients with eLTs. After Der p 1 challenge ex vivo, Iε-Cμ transcript was detected only in eosinophilic polyps with eLTs but not in polyps without eLTs and noneosinophilic polyps. eLTs might support local immunoglobulin production and therefore significantly contribute to the development of CRSwNP. Copyright © 2017 American Academy of

Development of artificial muscles based on electroactive ionomeric polymer-metal composites.

Science.gov (United States)

Hirano, Laos A; Escote, Márcia T; Martins-Filho, Luiz S; Mantovani, Gerson L; Scuracchio, Carlos H

2011-05-01

This work contextualizes the research of materials that can be applied as artificial muscles. The main motivation of this research is the importance of the development of mechatronic systems for the replacement of traditional devices of actuation and motion based on rotational electrical motors by other devices that reproduce biological muscle movements. Electroactive polymers (EAPs) are materials that respond to electric stimuli with shape and/or dimension changes, and accomplish movements that are smooth enough to mimic biological muscles. Among EAPs, the ionomeric polymer-metal composites (IPMCs) are an interesting alternative to biomimetic devices due to large displacements when submitted to low applied voltage. This article presents a brief review of IPMCs, a sample preparation procedure, and some electromechanical experimental results. We also discuss the applicability of this technology in medical devices and as artificial muscles. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Scaling from single molecule to macroscopic adhesion at polymer/metal interfaces.

Science.gov (United States)

Utzig, Thomas; Raman, Sangeetha; Valtiner, Markus

2015-03-10

Understanding the evolution of macroscopic adhesion based on fundamental molecular interactions is crucial to designing strong and smart polymer/metal interfaces that play an important role in many industrial and biomedical applications. Here we show how macroscopic adhesion can be predicted on the basis of single molecular interactions. In particular, we carry out dynamic single molecule-force spectroscopy (SM-AFM) in the framework of Bell-Evans' theory to gain information about the energy barrier between the bound and unbound states of an amine/gold junction. Furthermore, we use Jarzynski's equality to obtain the equilibrium ground-state energy difference of the amine/gold bond from these nonequilibrium force measurements. In addition, we perform surface forces apparatus (SFA) experiments to measure macroscopic adhesion forces at contacts where approximately 10(7) amine/gold bonds are formed simultaneously. The SFA approach provides an amine/gold interaction energy (normalized by the number of interacting molecules) of (36 ± 1)k(B)T, which is in excellent agreement with the interaction free energy of (35 ± 3)k(B)T calculated using Jarzynski's equality and single-molecule AFM experiments. Our results validate Jarzynski's equality for the field of polymer/metal interactions by measuring both sides of the equation. Furthermore, the comparison of SFA and AFM shows how macroscopic interaction energies can be predicted on the basis of single molecular interactions, providing a new strategy to potentially predict adhesive properties of novel glues or coatings as well as bio- and wet adhesion.

The differentiation and prognostic implication of the solitary colonic polyp and the polyposis syndromes: A radiologic, histologic, and pathologic approach

International Nuclear Information System (INIS)

Olmsted, W.W.; Lichtenstein, J.E.

1987-01-01

The differential diagnosis of the solitary colonic polyp and the implications and prognostic significance of the solitary colonic polyp and the polyposis syndromes are frequently confusing because of imprecise and overlapping terminology. Such confusion may lead to misdiagnosis or overdiagnosis and improper patient treatment and surveillance. In the first part of this course, basic terms are defined to acquaint all participants with current common ground. The most frequently occurring solitary polyps (e.g., the colonic adenoma, hyperplastic polyp, Peutz-Jeghers hamartoma, juvenile hamartoma, and inflammatory polyp) are illustrated in detail with radiologic-histologic-pathologic correlation. The prognostic significance of each type of lesion and a scheme for proper colonic surveillance is discussed. In the second part of the session, there is a thorough discussion of multiple colonic polyps and the polyposis syndromes. Radiologic-pathologic correlation are used to illustrate these entities, and therapeutic and diagnostic implications are thoroughly covered. The differential diagnosis of the polyposis syndromes, including lymphoid abnormalities, pneumatosis intestinalis, and colitis cystica profunda, are mentioned. The participant should expect to gain a full understanding of the solitary and multiple colonic polyp states and algorithms for prognosis and treatment

Polymer functionalized nanocomposites for metals removal from water and wastewater: An overview.

Science.gov (United States)

Lofrano, Giusy; Carotenuto, Maurizio; Libralato, Giovanni; Domingos, Rute F; Markus, Arjen; Dini, Luciana; Gautam, Ravindra Kumar; Baldantoni, Daniela; Rossi, Marco; Sharma, Sanjay K; Chattopadhyaya, Mahesh Chandra; Giugni, Maurizio; Meric, Sureyya

2016-04-01

Pollution by metal and metalloid ions is one of the most widespread environmental concerns. They are non-biodegradable, and, generally, present high water solubility facilitating their environmental mobilisation interacting with abiotic and biotic components such as adsorption onto natural colloids or even accumulation by living organisms, thus, threatening human health and ecosystems. Therefore, there is a high demand for effective removal treatments of heavy metals, making the application of adsorption materials such as polymer-functionalized nanocomposites (PFNCs), increasingly attractive. PFNCs retain the inherent remarkable surface properties of nanoparticles, while the polymeric support materials provide high stability and processability. These nanoparticle-matrix materials are of great interest for metals and metalloids removal thanks to the functional groups of the polymeric matrixes that provide specific bindings to target pollutants. This review discusses PFNCs synthesis, characterization and performance in adsorption processes as well as the potential environmental risks and perspectives. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rh-I-UEA-1 Polymerized Liposomes Target and Image Adenomatous Polyps in the APCMin/+ Mouse Using Optical Colonography

Directory of Open Access Journals (Sweden)

Celeste A. Roney

2011-07-01

Full Text Available Mutated adenomatous polyposis coli (APC genes predispose transformations to neoplasia, progressing to colorectal carcinoma. Early detection facilitates clinical management and therapy. Novel lectin-mediated polymerized targeted liposomes (Rh-I-UEA-1, with polyp specificity and incorporated imaging agents were fabricated to locate and image adenomatous polyps in APCMin/+ mice. The biomarker α-l-fucose covalently joins the liposomal conjugated lectin Ulex europaeus agglutinin (UEA-1, via glycosidic linkage to the polyp mucin layer. Multispectral optical imaging (MSI corroborated a global perspective of specific binding (rhodamine B 532 nm emission, 590–620 nm excitation of targeted Rh-I-UEA-1 polymerized liposomes to polyps with 1.4-fold labeling efficiency. High-resolution coregistered optical coherence tomography (OCT and fluorescence molecular imaging (FMI reveal the spatial correlation of contrast distribution and tissue morphology. Freshly excised APCMin bowels were incubated with targeted liposomes (UEA-1 lectin, control liposomes (no lectin, or iohexol (Omnipaque and imaged by the three techniques. Computed tomographic quantitative analyses did not confirm that targeted liposomes more strongly bound polyps than nontargeted liposomes or iohexol (Omnipaque alone. OCT, with anatomic depth capabilities, along with the coregistered FMI, substantiated Rh-I-UEA-1 liposome binding along the mucinous polyp surface. UEA-1 lectin denotes α-l-fucose biomarker carbohydrate expression at the mucin glycoprotein layer; Rh-I-UEA-1 polymerized liposomes target and image adenomatous polyps in APCMin mice.

The comparison of CT virtual colonoscopy with video colonoscopy (the detection of simulated polyps in pig colon)

International Nuclear Information System (INIS)

Tang Wen; Gong Jianping; Gao Zhixin; Lu Zhian

2000-01-01

Objective: To assess the value of CT virtual colonoscopy for the detection of simulated polyps in pig colon. Methods: Injecting the smelted wax under the mucosa to simulate the polyps in pig colon, then detected by video colonoscopy and scanned by helical CT. The images were obtained with collimation 3 mm, 5 mm, 10 mm and with the table pitch 1 and 2. All images were reconstructed at 1 mm intervals. Results: The shapes were depicted as follows: those greater than 10 mm in diameter polyps were clearly depicted. 5-9 mm in diameter polyps were faintly depicted. Those smaller than 5 mm in diameter were depicted difficulty. The details depicted: polyps larger than 10 mm in diameter and 5-9 mm in diameter were clearly depicted and that smaller than 5 mm in diameter were depicted difficulty. The images quality lowered with the increasing collimation and pitch. Conclusion: CT virtual colonoscopy is a non-invasive diagnostic technique. It can show the inner wall of colon as same as video colonoscopy does, and is a good alternative in clinical application

A study of TiN-coated metal-on-polymer bearing materials for hip prosthesis

Science.gov (United States)

Lee, Sung Bai; Choi, Jin Young; Park, Won Woong; Jeon, Jun Hong; Won, Sung Ok; Byun, Ji Young; Lim, Sang Ho; Han, Seung Hee

2010-08-01

The TiN-coated metal-on-polymer hip prosthetic pair has the potential to reduce wear debris of UHMWPE (ultra-high molecular weight polyethylene) and to prevent metallic-ion-induced cytotoxicity. However, high quality and adherent film is a key to the clinical success of hip prostheses. In this study, titanium nitride (TiN) films were deposited on stainless steel using plasma immersion ion implantation & deposition (PIII&D) technique to create high-quality film and an adherent interface. The chemical state and composition were analyzed by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and energy dispersive spectroscopy (EDS). The mechanical properties of the films were characterized using a micro-hardness tester and a pin-on-disk wear tester, and an x-ray diffractometer (XRD) was used for a crystallographic analysis. The PIII&D-treated TiN films showed a stoichiometric and (200) preferred orientation and micro-hardness up to 150 % higher than untreated film. A TiN-coated specimen using the PIII&D process also showed less UHMWPE wear compared to untreated specimens. The volumetric wear rate of UHMWPE could be reduced by as much as 42 % compared to when Co-Cr alloy was used. The results of this study show that advanced TiN-coating via the PIII&D process is a viable means of reducing UHMWPE wear in the metal-on-polymer bearing couple.

Plasma coatings of nitrogen polymers on metal prostheses of the circulatory system; Recubrimientos por plasma de polimeros nitrogenados sobre protesis metalicas del sistema circulatorio

Energy Technology Data Exchange (ETDEWEB)

Gomez J, L. M.

2016-07-01

This work has a study about the synthesis of poly aniline, poly allylamine and poly pyrrole doped with iodine onto metallic surfaces similar to stents for the circulatory system. Ar, water and hydrogen peroxide plasmas were used for eroding, conditioning and synthesizing polymers that potentially reduce some rejection reactions when stents are implanted in the human body. Stents are small metallic meshes that applied inside collapsed arteries or veins enlarge the diameter and restore the blood flow, however the metallic surfaces usually cause rejection reactions that obstruct the veins again. To give solutions to this problem, in this work is studied the synthesis of biocompatible polymer coatings on the stents that resist the blood flow forming a biocompatible interface between metal and blood. The metallic substrates were eroded and chemically prepared with Ar, H{sub 2}O and/or H{sub 2}O{sub 2} glow discharges on which the polymers were synthesized by plasma. The coatings were morphologically characterized by optical, scanning electron and atomic force microscopy, the chemical structure was studied by infrared and photoelectron X-ray spectroscopy. The hydrophilicity was studied measuring the advance static contact angle and the adhesion was evaluated indirectly with scanning electron microscopy after two months submerged in buffered phosphate solutions. The results indicate that the polymers grew following the superficial morphology; that the conditioning with Ar ions erode the substrates and that the conditioning with H{sub 2}O or H{sub 2}O{sub 2} erodes and activates the surface generating oxygen bridges which help in the polymer-metal adhesion. The chemical structure of the polymeric coatings contain crosslinked structures that correspond to links between monomers with the participation of all atoms, states that suggest monomer fragmentation and oxidation and states that indicate oxygen bridges in the polymers. The coatings had contact angles close to 90

Importance of X-ray diagnosis of colorectal polyps as compared to the endoscopic method

International Nuclear Information System (INIS)

Lass, B.

1980-01-01

The importance of X-ray diagnosis of colorectal polyps as compared with endoscopy is assessed on the basis of the literature and the authoress's own investigations. These make clean that the double contrast method attains a degree of accuracy approaching that of endoscopy. Some investigations by the authoress in 98 patients show that the procedure permits to recognize 72% of polyps under 1 cm of length and 81% above if the patients are well prepared. 4 out of 129 polyps were not detected by endoscopy. Coloscopy is not an infallible method. Both methods should not be viewed as rivalling but as complementary ones. Knowledge of the limitations and methods, and contant endeavour to combine all methods will entail the best diagnostic results. (orig.) [de

Ion Implantation of Polymers

DEFF Research Database (Denmark)

Popok, Vladimir

2012-01-01

The current paper presents a state-of-the-art review in the field of ion implantation of polymers. Numerous published studies of polymers modified by ion beams are analysed. General aspects of ion stopping, latent track formation and changes of structure and composition of organic materials...... are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...... is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed....

Formation of TiC/Al{sub 2}O{sub 3} composites from metal-polymer-precursors

Energy Technology Data Exchange (ETDEWEB)

Jost, H.; Braun, M.; Staedler, C. [Technische Univ. Berlin (Germany). Inst. fuer Nichtmetallische Werkstoffe

2002-07-01

A new synthesis route for TiC/Al{sub 2}O{sub 3} materials was developed starting from a mixed metal-polymer precursor. The Precursor was prepared from aluminium nitrate, titantetrachloride and polymethacrylic acid dissolved in a solvent in order to achieve a high homogeneity of the precursor reactants. (orig.)

A case of bilateral vocal fold mucosal bridges, bilateral trans-vocal fold type III sulci vocales, and an intracordal polyp.

Science.gov (United States)

Tan, Melin; Pitman, Michael J

2011-07-01

We present a patient with a novel finding of bilateral mucosal bridges, bilateral type III trans-vocal fold sulci vocales, and a vocal fold polyp. Although sulci and mucosal bridges occur in the vocal folds, it is rare to find multiples of these lesions in a single patient, and it is even more uncommon when they occur in conjunction with a vocal fold polyp. To our knowledge, this is the first description of a vocal fold polyp in combination with multiple vocal fold bridges and multiple type III sulci vocales in a single patient. To describe and visually present the diagnosis and treatment of a patient with an intracordal polyp, bilateral mucosal bridges, as well as bilateral type III trans-vocal fold sulci vocales. Presentation of a set of high definition intraoperative photos displaying the extent of the vocal fold lesions and the resection of the intracordal polyp. This patient presented with only 6 months of significant dysphonia. It was felt that the recent change in voice was because of the polyp and not the bridges or sulci vocales. Considering the patient's presentation and the possible morbidity of resection of mucosal bridges and sulci, only the polyp was excised. Postoperatively, the patient's voice returned to his acceptable mild baseline dysphonia, and the benefit has persisted 6 months postoperatively. The combination of bilateral mucosal bridges, bilateral type III sulcus vocalis, and an intracordal polyp in one patient is rare if not novel. Treatment of the polyp alone returned the patient's voice to his lifelong baseline of mild dysphonia. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

A combined semiempirical-DFT study of oligomers within the finite-chain approximation, evolution from oligomers to polymers.

Science.gov (United States)

Derosa, Pedro A

2009-06-01

A computationally cheap approach combining time-independent density functional theory (TIDFT) and semiempirical methods with an appropriate extrapolation procedure is proposed to accurately estimate geometrical and electronic properties of conjugated polymers using just a small set of oligomers. The highest occupied molecular orbital-lowest unoccupied molecular orbital gap (HLG) obtained at a TIDFT level (B3PW91) for two polymers, trans-polyacetylene--the simplest conjugated polymer, and a much larger poly(2-methoxy-5-(2,9-ethyl-hexyloxy)-1,4-phenylenevinylene (MEH-PPV) polymer converge to virtually the same asymptotic value than the excitation energy obtained with time-dependent DFT (TDDFT) calculations using the same functional. For TIDFT geometries, the HLG is found to converge to a value within the experimentally accepted range for the band gap of these polymers, when an exponential extrapolation is used; however if semiempirical geometries are used, a linear fit of the HLG versus 1/n is found to produce the best results. Geometrical parameters are observed to reach a saturation value in good agreement with experimental information, within the length of oligomers calculated here and no extrapolation was considered necessary. Finally, the performance of three different semiempirical methods (AM1, PM3, and MNDO) and for the TIDFT calculations, the performance of 7 different full electron basis sets (6-311+G**, 6-31+ +G**, 6-311+ +G**, 6-31+G**, 6-31G**, 6-31+G*, and 6-31G) is compared and it is determined that the choice of semiempirical method or the basis set does not significantly affect the results. 2008 Wiley Periodicals, Inc.

Polymer based tunneling sensor

Science.gov (United States)

Cui, Tianhong (Inventor); Wang, Jing (Inventor); Zhao, Yongjun (Inventor)

2006-01-01

A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer.

Ionic polymer metal composites with polypyrrole-silver electrodes

Science.gov (United States)

Cellini, F.; Grillo, A.; Porfiri, M.

2015-03-01

Ionic polymer metal composites (IPMCs) are a class of soft active materials that are finding increasing application in robotics, environmental sensing, and energy harvesting. In this letter, we demonstrate the fabrication of IPMCs via in-situ photoinduced polymerization of polypyrrole-silver electrodes on an ionomeric membrane. The composition, morphology, and sheet resistance of the electrodes are extensively characterized through a range of experimental techniques. We experimentally investigate IPMC electrochemistry through electrochemical impedance spectroscopy, and we propose a modified Randle's model to interpret the impedance spectrum. Finally, we demonstrate in-air dynamic actuation and sensing and assess IPMC performance against more established fabrication methods. Given the simplicity of the process and the short time required for the formation of the electrodes, we envision the application of our technique in the development of a rapid prototyping technology for IPMCs.

Flexible ITO-Free Polymer Solar Cells

DEFF Research Database (Denmark)

Angmo, Dechan; Krebs, Frederik C

2013-01-01

Indium tin oxide (ITO) is the material-of-choice for transparent conductors in any optoelectronic application. However, scarce resources of indium and high market demand of ITO have created large price fluctuations and future supply concerns. In polymer solar cells (PSCs), ITO is the single......-cost alternatives to ITO suitable for use in PSCs. These alternatives belong to four material groups: polymers; metal and polymer composites; metal nanowires and ultra-thin metal films; and carbon nanotubes and graphene. We further present the progress of employing these alternatives in PSCs and identify future...

Evidence-based investigation of the influence of computer-aided detection of polyps on screening of colon cancer with CT colonography

International Nuclear Information System (INIS)

Yoshida, Hiroyuki

2008-01-01

Computed tomographic colonography (CTC), also known as virtual colonoscopy, is a CT examination of the colon for colorectal neoplasms. Recent large-scale clinical trials have demonstrated that CTC yields sensitivity comparable to optical colonoscopy in the detection of clinically significant polyps in a screening population, making CTC a promising technique for screening of colon cancer. For CTC to be a clinically practical means of screening, it must reliably and consistently detect polyps with high accuracy. However, high-level expertise is required to interpret the resulting CT images to find polyps, resulting in variable diagnostic accuracy among radiologists in the detection of polyps. A key technology to overcome this problem and to bring CTC to prime time for screening of colorectal cancer is computer-aided detection (CAD) of polyps. CAD automatically detects the locations of suspicious polyps in CTC images and presents them to radiologists. CAD has the potential to increase diagnostic performance in the detection of polyps as well as to reduce variability of the diagnostic accuracy among radiologists. This paper presents an evidence-based investigation of the influence of CAD on screening of colon cancer with CTC by describing the benefits of using CAD in the diagnosis of CTC, the fundamental CAD scheme for the detection of polyps in CTC, its detection performance, the effect on the improvement of detection performance, as well as the current and future challenges in CAD. (author)

Interobserver agreement in the histologic diagnosis of colorectal polyps. the experience of the multicenter adenoma colorectal study (SMAC).

Science.gov (United States)

Costantini, Massimo; Sciallero, Stefania; Giannini, Augusto; Gatteschi, Beatrice; Rinaldi, Paolo; Lanzanova, Giuseppe; Bonelli, Luigina; Casetti, Tino; Bertinelli, Elisabetta; Giuliani, Orietta; Castiglione, Guido; Mantellini, Paola; Naldoni, Carlo; Bruzzi, Paolo

2003-03-01

Current clinical practice guidelines for patients with colorectal polyps are mainly based on the histologic characteristics of their lesions. However, interobserver variability in the assessment of specific polyp characteristics was evaluated in very few studies. The purpose of this study was to evaluate the interobserver agreement of four pathologists in the diagnosis of histologic type of colorectal polyps and in the degree of dysplasia and of infiltrating carcinoma in adenomas. A stratified random sample of 100 polyps was obtained from the 4,889 polyps resected within the Multicentre Adenoma Colorectal Study (SMAC), and the slides were blindly reviewed by the four pathologists. Agreement was analyzed using kappa statistics. A median kappa of 0.89 (range 0.79-1.0) was estimated for the interobserver agreement for the diagnosis of hyperplastic polyp vs. adenoma. The agreement in the diagnosis of tubular, tubulovillous, and villous type, was given by median kappa values of 0.50, 0.15, and 0.36, respectively. The median kappa for the diagnosis of infiltrating carcinoma was 0.78 (range 0.73-0.84). Agreement on diagnosis of adenoma histologic subtypes, degrees of dysplasia, or infiltrating carcinoma in adenoma was moderate. A simpler classifications might help to better identify patients at different risk of colorectal cancer.

Joining of polymer-metal lightweight structures using self-piercing riveting (SPR) technique: Numerical approach and simulation results

Science.gov (United States)

Amro, Elias; Kouadri-Henni, Afia

2018-05-01

Restrictions in pollutant emissions dictated at the European Commission level in the past few years have urged mass production car manufacturers to engage rapidly several strategies in order to reduce significantly the energy consumption of their vehicles. One of the most relevant taken action is light-weighting of body in white (BIW) structures, concretely visible with the increased introduction of polymer-based composite materials reinforced by carbon/glass fibers. However, the design and manufacturing of such "hybrid" structures is limiting the use of conventional assembly techniques like resistance spot welding (RSW) which are not transferable as they are for polymer-metal joining. This research aims at developing a joining technique that would eventually enable the assembly of a sheet molding compound (SMC) polyester thermoset-made component on a structure composed of several high strength steel grades. The state of the art of polymer-metal joining techniques highlighted the few ones potentially able to respond to the industrial challenge, which are: structural bonding, self-piercing riveting (SPR), direct laser joining and friction spot welding (FSpW). In this study, the promising SPR technique is investigated. Modelling of SPR process in the case of polymer-metal joining was performed through the building of a 2D axisymmetric FE model using the commercial code Abaqus CAE 6.10-1. Details of the numerical approach are presented with a particular attention to the composite sheet for which Mori-Tanaka's homogenization method is used in order to estimate overall mechanical properties. Large deformations induced by the riveting process are enabled with the use of a mixed finite element formulation ALE (arbitrary Lagrangian-Eulerian). FE model predictions are compared with experimental data followed by a discussion.

New polymer-supported ion-complexing agents: Design, preparation and metal ion affinities of immobilized ligands

International Nuclear Information System (INIS)

Alexandratos, Spiro D.

2007-01-01

Polymer-supported reagents are comprised of crosslinked polymer networks that have been modified with ligands capable of selective metal ion complexation. Applications of these polymers are in environmental remediation, ion chromatography, sensor technology, and hydrometallurgy. Bifunctional polymers with diphosphonate/sulfonate ligands have a high selectivity for actinide ions. The distribution coefficient for the uranyl ion from 1 M nitric acid is 70,000, compared to 900 for the monophosphonate/sulfonate polymer and 200 for the sulfonic acid ion-exchange resin. A bifunctional trihexyl/triethylammonium polymer has a high affinity and selectivity for pertechnetate and perchlorate anions from groundwater. In one example, its distribution coefficient for perchlorate ions in the presence of competing anions is 3,300,000, compared to 203,180 for a commercially available anion-exchange resin. Polystyrene modified with N-methyl-D-glucamine ligands is capable of selectively complexing arsenate from groundwater. It complexes 99% of the arsenate present in a solution of 100 mg/L arsenate with 560 mg/L sulfate ions. Its selectivity is retained even in the presence of 400 mg/L phosphate. There is no affinity for arsenate above pH 9, allowing for the polymer to be regenerated with moderate alkali solution. In studies aimed at developing a Hg(II)-selective resin, simple amine resins were found to have a high Hg(II) affinity and that affinity is dependent upon the solution pH and the counterion

Pre-exposure to simultaneous, but not individual, climate change stressors limits acclimation capacity of Irukandji jellyfish polyps to predicted climate scenarios

Science.gov (United States)

Klein, Shannon G.; Pitt, Kylie A.; Carroll, Anthony R.

2017-09-01

Researchers have investigated the immediate effects of end-of-century climate change scenarios on many marine species, yet it remains unclear whether we can reliably predict how marine species may respond to future conditions because biota may become either more or less resistant over time. Here, we examined the role of pre-exposure to elevated temperature and reduced pH in mitigating the potential negative effects of future ocean conditions on polyps of a dangerous Irukandji jellyfish Alatina alata. We pre-exposed polyps to elevated temperature (28 °C) and reduced pH (7.6), in a full factorial experiment that ran for 14 d. We secondarily exposed original polyps and their daughter polyps to either current (pH 8.0, 25 °C) or future conditions (pH 7.6, 28 °C) for a further 34 d to assess potential phenotypic plastic responses and whether asexual offspring could benefit from parental pre-exposure. Polyp fitness was characterised as asexual reproduction, respiration, feeding, and protein concentrations. Pre-exposure to elevated temperature alone partially mitigated the negative effects of future conditions on polyp fitness, while pre-exposure to reduced pH in isolation completely mitigated the negative effects of future conditions on polyp fitness. Pre-exposure to the dual stressors, however, reduced fitness under future conditions relative to those in the control treatment. Under future conditions, polyps had higher respiration rates regardless of the conditions they were pre-exposed to, suggesting that metabolic rates will be higher under future conditions. Parent and daughter polyps responded similarly to the various treatments tested, demonstrating that parental pre-exposure did not confer any benefit to asexual offspring under future conditions. Importantly, we demonstrate that while pre-exposure to the stressors individually may allow Irukandji polyps to acclimate over short timescales, the stressors are unlikely to occur in isolation in the long term, and

Pre-exposure to simultaneous, but not individual, climate change stressors limits acclimation capacity of Irukandji jellyfish polyps to predicted climate scenarios

KAUST Repository

Klein, Shannon G.; Pitt, Kylie A.; Carroll, Anthony R.

2017-01-01

Researchers have investigated the immediate effects of end-of-century climate change scenarios on many marine species, yet it remains unclear whether we can reliably predict how marine species may respond to future conditions because biota may become either more or less resistant over time. Here, we examined the role of pre-exposure to elevated temperature and reduced pH in mitigating the potential negative effects of future ocean conditions on polyps of a dangerous Irukandji jellyfish Alatina alata. We pre-exposed polyps to elevated temperature (28 °C) and reduced pH (7.6), in a full factorial experiment that ran for 14 d. We secondarily exposed original polyps and their daughter polyps to either current (pH 8.0, 25 °C) or future conditions (pH 7.6, 28 °C) for a further 34 d to assess potential phenotypic plastic responses and whether asexual offspring could benefit from parental pre-exposure. Polyp fitness was characterised as asexual reproduction, respiration, feeding, and protein concentrations. Pre-exposure to elevated temperature alone partially mitigated the negative effects of future conditions on polyp fitness, while pre-exposure to reduced pH in isolation completely mitigated the negative effects of future conditions on polyp fitness. Pre-exposure to the dual stressors, however, reduced fitness under future conditions relative to those in the control treatment. Under future conditions, polyps had higher respiration rates regardless of the conditions they were pre-exposed to, suggesting that metabolic rates will be higher under future conditions. Parent and daughter polyps responded similarly to the various treatments tested, demonstrating that parental pre-exposure did not confer any benefit to asexual offspring under future conditions. Importantly, we demonstrate that while pre-exposure to the stressors individually may allow Irukandji polyps to acclimate over short timescales, the stressors are unlikely to occur in isolation in the long term, and

Pre-exposure to simultaneous, but not individual, climate change stressors limits acclimation capacity of Irukandji jellyfish polyps to predicted climate scenarios

KAUST Repository

Klein, Shannon G.

2017-05-20

Researchers have investigated the immediate effects of end-of-century climate change scenarios on many marine species, yet it remains unclear whether we can reliably predict how marine species may respond to future conditions because biota may become either more or less resistant over time. Here, we examined the role of pre-exposure to elevated temperature and reduced pH in mitigating the potential negative effects of future ocean conditions on polyps of a dangerous Irukandji jellyfish Alatina alata. We pre-exposed polyps to elevated temperature (28 °C) and reduced pH (7.6), in a full factorial experiment that ran for 14 d. We secondarily exposed original polyps and their daughter polyps to either current (pH 8.0, 25 °C) or future conditions (pH 7.6, 28 °C) for a further 34 d to assess potential phenotypic plastic responses and whether asexual offspring could benefit from parental pre-exposure. Polyp fitness was characterised as asexual reproduction, respiration, feeding, and protein concentrations. Pre-exposure to elevated temperature alone partially mitigated the negative effects of future conditions on polyp fitness, while pre-exposure to reduced pH in isolation completely mitigated the negative effects of future conditions on polyp fitness. Pre-exposure to the dual stressors, however, reduced fitness under future conditions relative to those in the control treatment. Under future conditions, polyps had higher respiration rates regardless of the conditions they were pre-exposed to, suggesting that metabolic rates will be higher under future conditions. Parent and daughter polyps responded similarly to the various treatments tested, demonstrating that parental pre-exposure did not confer any benefit to asexual offspring under future conditions. Importantly, we demonstrate that while pre-exposure to the stressors individually may allow Irukandji polyps to acclimate over short timescales, the stressors are unlikely to occur in isolation in the long term, and