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1

Accelerated Clearance of Polyethylene Glycol-Modified Proteins by Anti-Polyethylene Glycol IgM  

Microsoft Academic Search

Tumor therapy by the preferential activation of a prodrug at tumor cells targeted with an antibody- enzyme conjugate may allow improved treatment efficacy with reduced side effects. We examined antibody-mediated clearance of poly(ethylene glycol)-modified ‚-glucuronidase (‚G-sPEG) as a method to reduce serum concentrations of enzyme and minimize systemic prodrug activation. Enzyme-linked immunosorbent assay and immunoblot analysis of two monoclonal antibodies

Tian-Lu Cheng; Pin-Yi Wu; Ming-Fang Wu; Ji-Wang Chern; Steve R. Roffler

1999-01-01

2

Surface forces and protein adsorption on dextran- and polyethylene glycol-modified polydimethylsiloxane.  

PubMed

Dextran and polyethylene glycol (PEG) are often covalently bound to the surface of polydimethylsiloxane (PDMS) for the purpose of modifying its hydrophilicity and biocompatibility. In this work, the effects of the dextran and PEG on the morphology, wetting, and surface charge of the resulting surfaces were quantified and correlated with changes in the amount of fibrinogen and albumin adsorbed from aqueous solution. PDMS films were functionalized in a microwave oxygen plasma to create surface hydroxyl groups that were subsequently aminated by incubation in a (3-aminopropyl)trimethoxysilane (APTES) solution. Oxidized dextran and PEG-aldehyde were linked to the surface amines via reductive amination. This process resulted in low surface coverage of immobilized PEG in the end-on conformation and a more uniform and dense distribution of side-on immobilized dextran. The immobilized dextran reduced the contact angle of the PDMS film from 109° to 80° and neutralized the zeta potential over the pH range from 3 to 11. An atomic force microscope was used to measure the interaction force between the modified PDMS and a model hydrophobic surface (polystyrene latex) and a model hydrophilic surface (silica) in aqueous solution to show that van der Waals and hydrophobic attractive forces are the dominant forces for protein adsorption in this system. The PEG- and dextran-modified PDMS were exposed to BSA and fibrinogen to test their resistance to protein adsorption. The coatings were ineffective at reducing the adsorption of either molecule, and the dextran-modification of the PDMS caused more BSA to adsorb than in the case of the unmodified PDMS. PMID:20801620

Farrell, Megan; Beaudoin, Stephen

2010-12-01

3

Antitumor Effect of Poly(Ethylene Glycol)Modified Fullerene  

Microsoft Academic Search

Water-insoluble fullerene (C60) was chemically modified with poly(ethylene glycol) (PEG) to solubilize it in water. The C60-PEG conjugates, upon injecting intravenously, were accumulated in the tumor to a greater extent than in the normal tissue and exhibited prolonged C60 retention at the tumor tissue. Conjugate injection followed by light irradiation significantly suppressed the volume increase of tumor. We conclude that

Yasuhiko Tabata; Yoshiyuki Murakami; Yoshito Ikada

1997-01-01

4

Effect of supercritical carbon dioxide as an exfoliation aid on bio-based polyethylene terephthalate glycol-modified/clay nanocomposites  

NASA Astrophysics Data System (ADS)

Bio-based PETG (bio-based glycol modified polyethylene terephthalate, Ecozen T95) / clay (organo-modified montmorillonite, OMMT, C10A) nanocomposites were prepared by co-rotating twin screw extruder attached with supercritical carbon dioxide (scCO2) injection system. The effects of nano-clay and scCO2 on the properties of PETG/clay nanocomposites were investigated by measuring thermal, rheological, tensile, impact, and barrier properties. The thermal and mechanical properties decreased with increasing nano-clay content, but they recovered or even exceeded the properties of neat PETG as scCO2 was added. It was verified due to a good dispersion of the nano-clay in PETG matrix for PETG/clay nanocomposites by XRD, SEM, and TEM. It was thought that scCO2 could be an effective exfoliation agent for many nanocomposites systems as well as for bio-based PET/clay nanocomposites.

Jang, Kwangho; Lee, Jae Wook; Hong, In-Kwon; Lee, Sangmook

2013-08-01

5

Transport and functional behaviour of poly(ethylene glycol)-modified nanoporous alumina membranes  

NASA Astrophysics Data System (ADS)

The development of hybrid organic-inorganic membranes with a low propensity for protein adsorption and highly uniform nanometre size pores is described. Poly(ethylene glycol) (PEG) monolayers were grafted to nanoporous alumina membranes using covalent silane and physical adsorption poly(ethyleneimine) (PEI) immobilization chemistries. X-ray photoelectron spectroscopy (XPS) and electron microscopy were used to investigate the chemical and physical surface properties of the membranes. The adsorption behaviour of a serum albumin on the membranes was characterized with fluorescence spectroscopy and it was determined that the PEG coating reduced nonspecific protein adsorption to a level too small to be measured. The gas and liquid permeabilities of membranes were measured to determine if the surface chemistries changed the functional behaviour of the membranes. Surprisingly, the silane chemistry produced little change in the permeabilities while polymer adsorption resulted in a total loss of water permeability. The diffusion of ovalbumin through the membranes was also measured and compared with a theoretical value. Diffusion of ovalbumin through the silane-PEG-modified membranes was found to be 50% slower than the unmodified membranes, which suggests that the pores are coated with a dense film of PEG. These results suggest that hybrid organic-inorganic membranes can provide significantly improved functional behaviour over existing organic or inorganic membranes.

Lee, Sang Won; Shang, Hao; Haasch, Richard T.; Petrova, Vania; Lee, Gil U.

2005-08-01

6

Sorption of adamantanes on polyethylene glycol-modified graphitized thermal soot  

NASA Astrophysics Data System (ADS)

The thermodynamic characteristics of sorption of adamantane and its functional derivatives on graphitized thermal soot (GTS) modified with polyethylene glycol Carbowax 20M were determined by equilibrium gas chromatography. The resulting thermodynamic characteristics were analyzed and compared with the data measured for adamantanes on the surface of nonmodified GTS and polyethylene glycol deposited on an inert substrate. The solid carbon substrate was shown to affect the character of intermolecular interactions in the GTS-modifier system and the retention of framework compounds under the conditions of gas, liquid, and solid-state chromatography.

Yashkin, S. N.; Ageeva, Yu. A.

2014-04-01

7

Non-Fouling Character of Poly[2-(methacryloyloxy)ethyl Phosphorylcholine]-Modified Gold Surfaces Fabricated by the 'Grafting to' Method: Comparison of its Protein Resistance with Poly(ethylene glycol)-Modified Gold Surfaces.  

PubMed

Poly[2-(methacryloyloxy)ethyl phosphorylcholine] -modified gold surfaces, which have been newly prepared by a 'grafting to' method using a series of monosulfanyl-terminated PMPC, are characterized by protein adsorption experiments based on surface plasmon resonance spectroscopy and ellipsometry measurements. The extent of BSA adsorption on PMPC-modified surfaces was systematically reduced for thicker PMPC layers, thus the number of MPC units on the gold surface appears to be an important factor for the excellent protein resistance offered by PMPC-modified gold surfaces fabricated by the 'grafting to' method, which is sharp contrast to that of PEG tethered chains. PMID:21638507

Yoshimoto, Keitaro; Hirase, Takumi; Madsen, Jeppe; Armes, Steven P; Nagasaki, Yukio

2009-12-16

8

Poly(ethylene glycol)-modified ligninase enhances pentachlorophenol biodegradation in water-solvent mixtures  

Microsoft Academic Search

Polychlorinated hydrocarbons are prevalent environmental contaminants whose rates of biodegradation are limited by their minimal solubilities in aqueous solutions where the biological reactions take place. In this study, ligninase (LiP) from Phanerochaete chrysosporium was modified by poly(ethylene glycol) to enhance its activity and stability for the biodegradation of pentachlorophenol (PCP) in the presence of acetonitrile (MeCN), a water-miscible solvent. The

Ping Wang; Charlene A. Woodward; Eric N. Kaufman

1999-01-01

9

Comparative studies of polyethylene glycol-modified liposomes prepared using different PEG-modification methods.  

PubMed

To address the issue of excess polyethylene glycol (PEG)-lipid degradation observed when PEG-modified liposomes are prepared using the pH-gradient method, a concept using a novel PEG-modification method, called the post-modification method, was proposed and evaluated. To assess the proof concept, a preservation-stability study and a pharmacokinetic study were performed that compared the conventional PEG-modification method, called the pre-modification method, with the post-modification method. The results show that PEG-lipid degradation could be markedly inhibited in the post-modification method. Furthermore, the post-modification method could be used without any manufacturing process difficulties, especially with high PEG-lipid content. In addition, a higher blood circulation capability was observed in the post-modification method. Through comparative studies, it was found that the post-modification method was advantageous compared to the pre-modification method. In conclusion, the post-modification method has the potential to be a novel PEG-modification method that can achieve a higher preservation stability of PEG-lipid, a greater ease of manufacturing, and a higher blood circulation capability, especially in the manufacturing of pH-gradient liposomal products. PMID:22766474

Nakamura, Koji; Yamashita, Keiko; Itoh, Yuki; Yoshino, Keisuke; Nozawa, Shigenori; Kasukawa, Hiroaki

2012-11-01

10

Polyethylene Glycol Modified, Cross-Linked Starch Coated Iron Oxide Nanoparticles for Enhanced Magnetic Tumor Targeting  

PubMed Central

While successful magnetic tumor targeting of iron oxide nanoparticles has been achieved in a number of models, the rapid blood clearance of magnetically suitable particles by the reticuloendothelial system (RES) limits their availability for targeting. This work aimed to develop a long-circulating magnetic iron oxide nanoparticle (MNP) platform capable of sustained tumor exposure via the circulation and, thus, enhanced magnetic tumor targeting. Aminated, cross-linked starch (DN) and aminosilane (A) coated MNPs were successfully modified with 5 kDa (A5, D5) or 20 kDa (A20, D20) polyethylene glycol (PEG) chains using simple N-Hydroxysuccinimide (NHS) chemistry and characterized. Identical PEG-weight analogues between platforms (A5 & D5, A20 & D20) were similar in size (140–190 nm) and relative PEG labeling (1.5% of surface amines – A5/D5, 0.4% – A20/D20), with all PEG-MNPs possessing magnetization properties suitable for magnetic targeting. Candidate PEG-MNPs were studied in RES simulations in vitro to predict long-circulating character. D5 and D20 performed best showing sustained size stability in cell culture medium at 37°C and 7 (D20) to 10 (D5) fold less uptake in RAW264.7 macrophages when compared to previously targeted, unmodified starch MNPs (D). Observations in vitro were validated in vivo, with D5 (7.29 hr) and D20 (11.75 hr) showing much longer half-lives than D (0.12 hr). Improved plasma stability enhanced tumor MNP exposure 100 (D5) to 150 (D20) fold as measured by plasma AUC0-? Sustained tumor exposure over 24 hours was visually confirmed in a 9L-glioma rat model (12 mg Fe/kg) using magnetic resonance imaging (MRI). Findings indicate that both D5 and D20 are promising MNP platforms for enhanced magnetic tumor targeting, warranting further study in tumor models.

Cole, Adam J.; David, Allan E.; Wang, Jianxin; Galban, Craig J.; Hill, Hannah L.; Yang, Victor C.

2010-01-01

11

Polyethylene glycol modified magnetic carbon nanotubes as nanosorbents for the determination of methylprednisolone in rat plasma by high performance liquid chromatography.  

PubMed

In this paper, polyethylene glycol modified (PEGylated) magnetic carbon nanotubes were developed as solid-phase extraction nanosorbents for the determination of methylprednisolone in rat plasma. The procedure mainly involved two steps including preparation of PEGylated magnetic nanosorbents and bioanalysis. Monodisperse magnetites (Fe3O4) anchored onto multi-walled carbon nanotubes (MWCNTs) were synthesized by a facile solvothermal synthesis method. The obtained MWCNTs-Fe3O4 nanomaterials were further non-covalently functionalized by a surfactant phospholipids-polyethylene glycol (DSPE-PEG). Owing to dispersibility and high enrichment ability, water-soluble PEGylated MWCNTs-Fe3O4 nanomaterials can provide more efficient way for the extraction of methylprednisolone than only MWCNTs-Fe3O4 used. The methylprednisolone could be easily extracted via ?-? stacking interactions with PEGylated MWCNTs-Fe3O4. The captured methylprednisolone/nanosorbents were isolated from the matrix by placing a magnet, and desorbed by the elution solvent composed of acetonitrile. Extraction conditions such as amount of nanosorbents added, adsorption time, desorption solvent, and desorption time were investigated and optimized. The method recoveries were obtained from 88.2% to 92.9%. Limits of quantification and limits of detection of 0.01 and 0.005?g/mL were acquired, respectively. The precision ranged from 4.2% to 7.8% for within-day measurement, and for between-day variation was in the range of 5.5-9.0%. Moreover, the analytical performance obtained by PEGylated magnetic MWCNTs was compared with that of magnetic MWCNTs. The results indicated that the approach based on PEGylated magnetic MWCNTs was useful for the analysis of methylprednisolone in the complex plasma. PMID:24837418

Yu, Panfeng; Ma, Hongwei; Shang, Yong; Wu, Ji; Shen, Shun

2014-06-27

12

Poly(ethylene glycol) modified [60]fullerene as electron buffer layer for high-performance polymer solar cells  

NASA Astrophysics Data System (ADS)

A poly(ethylene glycol) end caped fullerene derivative, PEGN-C60, is used as electron buffer layer (EBL) in polymer solar cells (PSCs). Three donor:acceptor blends, namely P3HT:PCBM, PBDTTT-C:PC70BM, and PBDTTT-C-T:PC70BM, are employed to test the behavior of PEGN-C60 as EBL. The optimized power conversion efficiencies of the three systems reach 3.84%, 6.22%, 7.45%, respectively, which are slightly higher than that of their corresponding devices with metal Ca as EBL and much higher than that of their devices without any EBLs. Our results indicate that exploring EBLs based on fullerene derivatives might be an efficient way in finding functional solution-processable EBLs for high-performance PSCs.

Zhang, Zhi-Guo; Li, Hui; Qi, Zhe; Jin, Zhiwen; Liu, Guo; Hou, Jianhui; Li, Yongfang; Wang, Jizheng

2013-04-01

13

Comparative studies of irinotecan-loaded polyethylene glycol-modified liposomes prepared using different PEG-modification methods.  

PubMed

Recently, a polyethylene glycol (PEG)-modification method for liposomes prepared using pH-gradient method has been proposed. The differences in the pharmacokinetics and the impact on the antitumor effect were examined; however the impact of PEG-lipid molar weight has not been investigated yet. The main purpose of this study is to evaluate the impact of PEG-lipid molar weight against the differences in the pharmacokinetics, the drug-release profile, and the antitumor effect between the proposed PEG-modification method, called the post-modification method, and the conventional PEG-modification method, called the pre-modification method. Various comparative studies were performed using irinotecan as a general model drug. The results showed that PEG-lipid degradation could be markedly inhibited in the post-modification method. Furthermore, prolonged circulation time was observed in the post-modification method. The sustained drug-release was observed in the post-modification method by the results of the drug-releasing test in plasma. Moreover, a higher antitumor effect was observed in the post-modification method. It was also confirmed that the same behaviors were observed in all comparative studies even though the PEG molecular weight was lower. In conclusion, the post-modification method has the potential to be a valuable PEG-modification method that can achieve higher preservation stability of PEG-lipid, prolonged circulation time, and higher antitumor effect with only half the amount of PEG-lipid as compared to the pre-modification method. Furthermore, it was demonstrated that PEG(5000)-lipid would be more desirable than PEG(2000)-lipid since it requires much smaller amount of PEG-lipid to demonstrate the same performances. PMID:22828450

Yoshino, Keisuke; Nakamura, Koji; Terajima, Yoko; Kurita, Akinobu; Matsuzaki, Takeshi; Yamashita, Keiko; Isozaki, Masashi; Kasukawa, Hiroaki

2012-11-01

14

Locoregional therapy with polyethylene-glycol-modified interleukin-2 of an intradermally growing hepatocellular carcinoma in the guinea pig induces T-cell-mediated antitumor activity  

Microsoft Academic Search

Therapy with repeated intratumoral and perilymphatic administration of relatively low doses of polyethylene-glycol(PEG)-modified interleukin-2 (IL-2) in the syngeneic guinea pig line 10 (L10) hepatocarcinoma results in significant local tumor growth inhibition and a delay in development of regional lymph node metastases of more than 3 weeks when compared to controls. Occasionally animals are cured of tumor. The mechanism of this

L. T. M. Balemansl; V. Mattijssen; P. A. Steerenberg; B. E. M. Van Driel; P. H. M. De Mulder; W. Den Otter

1993-01-01

15

Polyethylene glycol modified-albumin enhances the cold preservation properties of University of Wisconsin solution in rat liver and a hepatocyte cell line.  

PubMed

Liver grafts preserved in cold storage undergo changes mainly manifested by morphological modifications of the sinusoidal endothelium that result in poor graft function upon reperfusion. The present studies aimed to determine if the addition of polyethylene glycol-albumin to University of Wisconsin (Peg-AlbUW) solution ameliorates the cold preservation injuries of liver grafts. Rat livers were preserved cold with various preservation solutions and evaluated for weight changes and endothelial morphology. Solutions that preserved graft weight and endothelial morphology were tested in the isolated perfused rat liver model to assess graft function. A rat hepatocyte cell line was evaluated for both viability and glutathione concentrations emulating cold preservation and reperfusion conditions. Liver grafts preserved with Peg-AlbUW maintained their initial weight and showed a conserved endothelial morphology compared with liver grafts preserved in UW for 30 h (P<0.05). Liver grafts preserved with Peg-AlbUW had improved portal blood flow and bile secretion compared with liver grafts preserved in UW for 30 h (P<0.05). In vitro we noted comparable hepatocyte viability when cells were preserved in Peg-AlbUW versus UW under similar preservation conditions (P>0.05); glutathione concentrations (reduced and total) were significantly increased in hepatocytes preserved in 3% Peg-AlbUW compared with other preservation solutions (P<0.05). The addition of Peg-Alb to UW preservation solution ameliorated the cold preservation injuries of rat liver grafts as shown by stable liver graft weight, a better preservation of the endothelial morphology, improved portal vein blood flow, and increased bile secretion. Peg-Alb-UW solution improved the integrity of the glutathione redox buffer system of a hepatocyte cell line after cold storage and reperfusion. PMID:19577257

Abbas, Rime; Kombu, Rajan S; Dignam, David; Gunning, William; Stulberg, Jonah J; Brunengraber, Henri; Sanabria, Juan R

2010-11-01

16

Multidentate polyethylene glycol modified gold nanorods for in vivo near-infrared photothermal cancer therapy.  

PubMed

Gold nanorods (AuNRs), because of their strong absorption of near-infrared (NIR) light, are very suitable for in vivo photothermal therapy of cancer. However, appropriate surface modification must be performed on AuNRs before their in vivo application because of the high toxicity of their original stabilizer cetyltrimethylammonium bromide. Multidentate ligands have attracted a lot of attention for modification of inorganic nanoparticles (NPs) because of their high ligand affinity and multifunctionality, while the therapeutic effect of multidentate ligands modified NPs in vivo remains unexplored. Here, we modified AuNRs with a polythiol PEG-based copolymer. The multidentate PEG coated AuNRs (AuNR-PTPEGm950) showed good stabilities in high saline condition and wide pH range. And they had much stronger resistance to ligand competition of dithiothreitol (DTT) than AuNRs coated by monothiol-anchored PEG. The AuNR-PTPEGm950 had very low cytotoxicity and showed high efficacy for the ablation of cancer cells in vitro. Moreover, the AuNR-PTPEGm950 showed good stability in serum, and they had a long circulation time in blood that led to a high accumulation in tumors after intravenous injection. In vivo photothermal therapy showed that tumors were completely cured without reoccurrence by one-time irradiation of NIR laser after a single injection of these multidentate PEG modified AuNRs. PMID:24673744

Liu, Xiangsheng; Huang, Nan; Li, Huan; Wang, Haibo; Jin, Qiao; Ji, Jian

2014-04-23

17

Polyethylene Glycol on Stability of Chitosan Microparticulate Carrier for Protein  

Microsoft Academic Search

Stability enhancement of protein-loaded chitosan microparticles under storage was investigated. Chitosan glutamate at 35 kDa\\u000a and bovine serum albumin as model protein drug were used in this study. The chitosan microparticles were prepared by ionotropic\\u000a gelation, and polyethylene glycol 200 (PEG 200) was applied after the formation of the particles. All chitosan microparticles\\u000a were kept at 25°C for 28 days. A comparison

Manee Luangtana-anan; Sontaya Limmatvapirat; Jurairat Nunthanid; Rapeepun Chalongsuk; Keiji Yamamoto

2010-01-01

18

Protein adsorption on various plasma-treated polyethylene terephthalate substrates.  

PubMed

Protein adhesion and cell response to plasma-treated polymer surfaces were studied. The polymer polyethylene terephthalate (PET) was treated in either an oxygen plasma to make the surface hydrophilic, or a tetrafluoromethane CF(4) plasma to make the surface hydrophobic. The plasma source was radiofrequency (RF) discharge. The adsorption of albumin and other proteins from a cell-culture medium onto these surfaces was studied using a quartz crystal microbalance (QCM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The cellular response to plasma-treated surfaces was studied as well using an MTT assay and scanning electron microscopy (SEM). The fastest adsorption rate was found on the hydrophilic oxygen plasma-treated sample, and the lowest was found on the pristine untreated sample. Additionally, the amount of adsorbed proteins was higher for the oxygen-plasma-treated surface, and the adsorbed layer was more viscoelastic. In addition, cell adhesion studies support this finding because the best cell adhesion was observed on oxygen-plasma-treated substrates. PMID:24152668

Recek, Nina; Jaganjac, Morana; Kolar, Metod; Milkovic, Lidija; Mozeti?, Miran; Stana-Kleinschek, Karin; Vesel, Alenka

2013-01-01

19

Amperometric glucose-sensing electrode based on carbon paste containing poly (ethylene glycol)-modified glucose oxidase and cobalt octaethoxyphthalocyanine  

Microsoft Academic Search

An amperometric enzyme electrode for glucose was prepared by incorporating poly (ethylene glycol)-modified glucose oxidase and cobalt octaethoxyphthalocyanine [CoPc(OEt)8], a new mediator, into a carbon paste matrix. The polymer-modified enzyme exhibited a higher activity than the native enzyme in the hydrophobic carbon paste medium. CoPc(OEt)8 could oxidize the enzyme at more negative potentials than unsubstituted cobalt phthalocyanine (CoPc). Further, the

Fumio Mizutani; Soichi Yabuki; Seiichiro Iijima

1995-01-01

20

Protein immobilization to polystyrene via long poly(ethylene lycol) chains.  

PubMed

Human albumin has been attached to 24-hole polystyrene plates via branched poly(ethylene lycol) (PEG) spacer arms. A tetraepoxude of PEG of molecular weight (1.4-1.5) x 10(4) g/mol was reacted with the protein in solution allowing approximately one-third of the oxirane rings to react. The protein conjugate was then coupled to the long, cationic polymer poly(ethylene imine) (PEI), and the protein-PEG-PEI adduct was subsequently adsorption to unmodified polystyrene. Since the protein is linked to the surface via long, hydrophilic and nonchargedchains, interactions between the biomolecule and the surface is minimized. PMID:18600852

Bergström, K; Holmberg, K

1991-10-20

21

Effect of Chain Density on Inhibition of Protein Adsorption by Poly(ethylene glycol) Based Coatings  

Microsoft Academic Search

The effect of interfacial chain density of poly(ethylene glycol) (PEG) on the adsorption of serum proteins was investigated byin situellipsometry. For terminal covalently grafted PEG of molecular weight 5000 an increased grafting density results in decreased serum protein adsorption. At high interfacial chain density (?0.1 chain\\/nm2), efficient protein rejection was observed, irrespective of the coupling chemistry used. Strongly adsorbed PEG-containing

Martin Malmsten; Ken Emoto; James M. Van Alstine

1998-01-01

22

Protein carboxyl amidation increases the potential extent of protein polyethylene glycol conjugation.  

PubMed

Chemical coupling of polyethylene glycol (PEG) to therapeutic proteins reduces their immunogenicity and prolongs their circulating half-life. The limitation of this approach is the number and distribution of sites on proteins available for PEGylation (the N terminus and the -amino group of lysines). To increase the extent of PEGylation, we have developed a method to increase the number of PEGylation sites in a model protein, recombinant methionine alpha,gamma-lyase (recombinant methioninase; rMETase), an enzyme cancer therapeutic cloned from Pseudomonas putida. rMETase was first PEGylated with methoxypolyethylene glycol succinimidyl glutarate-5000 with a molar ratio of PEG:rMETase of 15:1. The carboxyl groups of the initially PEGylated protein were then conjugated with diaminobutane, resulting in carboxyl amidation. This reaction was catalyzed by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, a water-soluble carbodiimide. The steric hindrance provided by the PEG chains already coupled to the protein prevented cross-linking between rMETase molecules during the carboxyl amidation reaction. The carboxyl-amidated PEGylated rMETase was hyper-PEGylated at a molar ratio of PEG to PEG-rMETase of 60:1. Biochemical analysis indicated that 13 PEG chains were coupled to each subunit of rMETase after hyper-PEGylation compared with 6-8 PEG chains attached to the non-carboxyl-amidated PEG-rMETase. Approximately 15-20% of the non-PEGylated rMETase activity was retained in the hyper-PEGylated molecule. Immunogenicity of the hyper-PEG-rMETase was significantly reduced relative to PEG-rMETase and rMETase. Initial results suggest that hyper-PEGylation may become a new strategy for PEGylation of protein biologics. PMID:15203332

Li, Shukuan; Yang, Zhijian; Sun, Xinghua; Tan, Yuying; Yagi, Shigeo; Hoffman, Robert M

2004-07-15

23

New Insight into the Role of Polyethylene Glycol Acting as Protein Release Modifier in Lipidic Implants  

Microsoft Academic Search

Purpose  It has recently been shown that the addition of polyethylene glycol 6000 (PEG) to lipidic implants fundamentally affects the\\u000a resulting protein release kinetics and moreover, the underlying mass transport mechanisms (Herrmann, Winter, Mohl, F. Siepmann,\\u000a & J. Siepmann, J. Control. Release, 2007). However, it is yet unclear in which way PEG acts. It was the aim of this study to

Sandra Herrmann; Silke Mohl; Florence Siepmann; Juergen Siepmann; Gerhard Winter

2007-01-01

24

Poly(ethylene glycol)Protein, Peptide, and Enzyme Conjugates  

Microsoft Academic Search

\\u000a Recently many bioactive peptides and proteins, in particular enzymes, have found successful pharmacological applications for\\u000a anticancer therapy due not only to a direct antiproliferative action but also when used as adjuvant therapeutics either to\\u000a control some side effects or to enhance the activity of anticancer drugs. However, to be effectively adopted in a suitable\\u000a therapeutic protocol they need to be

F. M. Veronese; G. Pasut; S. Drioli; G. M. Bonora

25

Recombinant Ganoderma lucidum immunomodulatory protein modified with polyethylene glycol.  

PubMed

Recombinant Ganoderma lucidum immunomodu-latory protein (rLZ-8) expressed using the Pichia yeast eukaryotic expression system is a potential new drug for cancer therapy; however, it has a short half-life in the body. In order to optimize the potency and stability of rLZ-8, we modified the recombinant protein chemically using methoxy-PEG-succinimidyl propionate (mPEG-SPA). The results indicated that several parameters, including pH, the molar ratio of rLZ-8 to mPEG-SPA and time, played crucial roles in the modification process. In particular, when the molar ratio of rLZ-8 to mPEG-SPA was 1:1, rLZ-8 was modified by a single mPEG-SPA moiety. In addition, MALDI-TOF/TOF and ESI Q-Trap results revealed that the difference in molecular weight (MW) between the peptide-linked mPEG-SPA and the mPEG-SPA closely matched the MW of a methionine amino acid. Taken together, these data suggest that modification of mPEG-SPA occurred on the N-terminal helix of rLZ-8. This modification method has laid a foundation for the development of long-acting formulations of rLZ-8. PMID:23338950

Zhang, Xiping; Sun, Fei; Liu, Zhiyi; Zhang, Shuqin; Liang, Chongyang

2013-03-01

26

Effect of chain density on inhibition of protein adsorption by poly(ethylene glycol) based coatings  

SciTech Connect

The effect of interfacial chain density of poly(ethylene glycol) (PEG) on the adsorption of serum proteins was investigated by in situ ellipsometry. For terminal covalently grafted PEG of molecular weight 5,000 an increased grafting density results in decreased serum protein adsorption. At high interfacial chain density ({approx}0.1 chain/nm{sup 2}), efficient protein injection was observed, irrespective of the coupling chemistry used. Strongly adsorbed PEG-containing polymers behaved similarly to covalently attached PEG regarding inhibition of protein adsorption, independent of the nature of the underlying surface. The results are discussed in relation to the importance of the protein size in protein rejection by PEG coatings.

Malmsten, M. [Inst. for Surface Chemistry, Stockholm (Sweden)] [Inst. for Surface Chemistry, Stockholm (Sweden); Emoto, K. [Univ. of Alabama, Huntsville, AL (United States). Dept. of Chemistry] [Univ. of Alabama, Huntsville, AL (United States). Dept. of Chemistry; Van Alstine, J.M. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering and Technology] [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering and Technology

1998-06-15

27

Sustained release of protein from poly(ethylene glycol) incorporated amphiphilic comb like polymers.  

PubMed

Amphiphilic comb like macromonomer containing hydrophilic poly(ethylene glycol) groups covalently linked to poly(hydromethyl siloxane) (PHMS) were prepared by hydrosilylation reaction. The epoxy reacting sites were introduced to this amphiphilic system by the reaction with allyl epoxy propyl ether (AEPE). Bovine serum albumin (BSA), a model protein drug was loaded to the PEG-PDMS system and very thin membranes were made from this macromonomer adopting solution casting technique. The in vitro protein release studies at various pH conditions showed a controlled release profile without exhibiting any initial burst. The control of the initial burst might be due to the strong linkages of the protein with the membrane and the aggregation of the protein at the surface. The morphology of the membrane before and after the protein release, and the mechanical strength were evaluated. The surface properties of the membrane were studied using the contact angle measurements. PMID:16930885

Srividhya, M; Preethi, S; Gnanamani, A; Reddy, B S R

2006-12-01

28

Interaction Forces and Morphology of a Protein-Resistant Poly(ethylene glycol) Layer  

PubMed Central

The molecular interactions on a protein-resistant surface coated with low-molecular-weight poly(ethylene glycol) (PEG) copolymer brushes are investigated using the extended surface forces apparatus. The observed interaction force is predominantly repulsive and nearly elastic. The chains are extended with respect to the Flory radius, which is in agreement with qualitative predictions of scaling theory. Comparison with theory allows the determination of relevant quantities such as brush length and adsorbed mass. Based on these results, we propose a molecular model for the adsorbed copolymer morphology. Surface-force isotherms measured at high resolution allow distinctive structural forces to be detected, suggesting the existence of a weak equilibrium network between poly(ethylene glycol) and water—a finding in accordance with the remarkable solution properties of PEG. The occurrence of a fine structure is interpreted as a water-induced restriction of the polymer's conformational space. This restriction is highly relevant for the phenomenon of PEG protein resistance. Protein adsorption requires conformational transitions, both in the protein as well as in the PEG layer, which are energetically and kinetically unfavorable.

Heuberger, M.; Drobek, T.; Spencer, N. D.

2005-01-01

29

Formation of protein complex with the aid of polyethylene glycol for deproteinized natural rubber latex  

NASA Astrophysics Data System (ADS)

The effect of polyethylene glycol (PEG) as a deproteinizing agent in commercial natural rubber latex (NRL) onto the physicochemical properties of the NRL was investigated. Three types of PEG were used namely PEG200, PEG4000 and PEG20000 (molecular weight of 200, 4000 and 20000 g/mol respectively). The optimum amount of PEG in NRL was determined from viscosity changes, protein content and Fourier Transform Infrared spectroscopy. Level of protein reduction was affected by molecular weight of PEG. The addition of PEG in NRL reduced the protein content of NRL (3.30 %) to the lowest (2.01 %) at 0.40 phr of PEG200 due to more attractive hydrophobic interactions between short chains PEG compared to PEG4000 (2.24%) and PEG20000 (2.15%). This was verified through FTIR spectroscopy analysis by observing the primary and secondary amide peak where PEG4000 has lesser absorption at the region compared to with PEG20000.

Wei, Lim Keuw; Ing, Wong Kwee; Badri, Khairiah Haji; Ban, Wong Chong

2013-11-01

30

A simple soft lithographic route to fabrication of poly(ethylene glycol) microstructures for protein and cell patterning  

Microsoft Academic Search

We present a simple, direct soft lithographic method to fabricate poly(ethylene glycol) (PEG) microstructures for protein and cell patterning. This lithographic method involves a molding process in which a uniform PEG film is molded with a patterned polydimethylsiloxane stamp by means of capillary force. The patterned surfaces created by this method provide excellent resistance towards non-specific protein and cell adsorption.

Kahp Y. Suh; Jiehyun Seong; Ali Khademhosseini; Paul E. Laibinis; Robert Langer

2004-01-01

31

Controlling microencapsulation and release of micronized proteins using poly(ethylene glycol) and electrospraying.  

PubMed

The fabrication of tailored microparticles for delivery of therapeutics is a challenge relying upon a complex interplay between processing parameters and materials properties. The emerging use of electrospraying allows better tailoring of particle morphologies and sizes than current techniques, critical to reproducible release profiles. While dry encapsulation of proteins is essential for the release of active therapeutics from microparticles, it is currently uncharacterized in electrospraying. To this end, poly(ethylene glycol) (PEG) was assessed as a micronizing and solubilizing agent for dry protein encapsulation and release from electrosprayed particles made from polycaprolactone (PCL). The physical effect of PEG in protein-loaded poly(lactic-co-glycolic acid) (PLGA) particles was also studied, for comparison. The addition of 5-15wt% PEG 6kDa or 35kDa resulted in reduced PCL particle sizes and broadened distributions, which could be improved by tailoring the electrospraying processing parameters, namely by reducing polymer concentration and increasing flow rate. Upon micronization, protein particle size was reduced to the micrometer domain, resulting in homogenous encapsulation in electrosprayed PCL microparticles. Microparticle size distributions were shown to be the most determinant factor for protein release by diffusion and allowed specific control of release patterns. PMID:24657821

Bock, Nathalie; Dargaville, Tim R; Woodruff, Maria A

2014-07-01

32

Measurements of Attractive Forces between Proteins and End-Grafted Poly(Ethylene Glycol) Chains  

NASA Astrophysics Data System (ADS)

The surface force apparatus was used to measure directly the molecular forces between streptavidin and lipid bilayers displaying grafted Mr 2,000 poly(ethylene glycol) (PEG). These measurements provide direct evidence for the formation of relatively strong attractive forces between PEG and protein. At low compressive loads, the forces were repulsive, but they became attractive when the proteins were pressed into the polymer layer at higher loads. The adhesion was sufficiently robust that separation of the streptavidin and PEG uprooted anchored polymer from the supporting membrane. These interactions altered the properties of the grafted chains. After the onset of the attraction, the polymer continued to bind protein for several hours. The changes were not due to protein denaturation. These data demonstrate directly that the biological activity of PEG is not due solely to properties of simple polymers such as the excluded volume. It is also coupled to the competitive interactions between solvent and other materials such as proteins for the chain segments and to the ability of this material to adopt higher order intrachain structures.

Sheth, S. R.; Leckband, D.

1997-08-01

33

Adhesive protein expression on endothelial cells after contact in vitro with polyethylene terephthalate coated with pyrolytic carbon  

Microsoft Academic Search

This research aims at evaluating the expression of some adhesive proteins on endothelial cell surface after contact with polyethylene terephthalate coated with pyrolytic carbon (PET + PC). Twenty-two different cultures of human umbilical vein endothelial cells (HUVECs) were put in contact with PET + PC. Both HUVECs grown without the biomaterial and HUVECs incubated with endotoxin were used as control.

E. Cenni; D. Granchi; C. R. Arciola; G. Ciapetti; L. Savarino; S. Stea; D. Cavedagna; A. Di Leo; A. Pizzoferrato

1995-01-01

34

Characterizing the modification of surface proteins with poly(ethylene glycol) to interrupt platelet adhesion  

PubMed Central

Surface protein modification with poly(ethylene glycol) (PEG) can inhibit acute thrombosis on damaged vascular and biomaterial surfaces by blocking surface protein–platelet interactions. However, the feasibility of employing protein reactive PEGs to limit intravascular and biomaterial thrombosis in vivo is contingent upon rapid and extensive surface protein modification. To characterize the factors controlling this potential therapeutic approach, the model protein bovine serum albumin was adsorbed onto polyurethane surfaces and modified with PEG-carboxymethyl succinimidyl ester (PEG-NHS), PEG-isocyanate (PEG-ISO), or PEG-diisocyanate (PEG-DISO) in aqueous buffer at varying concentrations and contact times. It was found that up to 5 PEGs could be attached per albumin molecule within one min and that adsorbed albumin PEGylation approached maximal levels by 6 min. The lability of reactive PEGs in aqueous buffer reduced total protein modification by 50% when the PEG solution was incubated for 7 min prior to application. For fibrinogen PEGylation (performed in the solution phase), PEG-NHS was more reactive than PEG-ISO or PEG-DISO. The ? peptide of fibrinogen, which contains several key platelet-binding motifs, was highly modified. A marked reduction in platelet adhesion was observed on fibrinogen-adsorbed polyurethane treated with PEG-NHS or PEG-DISO. Relative differences in platelet adhesion on PEG-NHS and PEG-DISO modified surfaces could be attributed to differences in reactivity towards fibrinogen and the size of the polymer backbone. Taken together, these findings provide insight and guidance for applying protein reactive PEGs for the interruption of acute thrombotic deposition.

Xu, Haiyan; Kaar, Joel L.; Russell, Alan J.; Wagner, William R.

2010-01-01

35

Effect of polyethylene glycol on the thermal stability of green fluorescent protein.  

PubMed

Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Some polymers, such as polyethylene glycol, are often used as modifiers of characteristics of biological macromolecules, to improve the biochemical activity and stability of proteins or drug bioavailability. The aim of this study was to evaluate the thermal stability of GFP in the presence of different PEG molar weights at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were almost constant for temperatures of 85, 90, and 95 degrees C, despite the PEG concentration or molar weight studied. Even though PEG can stabilize proteins, only at 75 degrees C, PEG 600 and 4,000 g/mol stabilized GFP. PMID:19856402

de Lencastre Novaes, Letícia C; Mazzola, Priscila G; Pessoa, Adalberto; Penna, Thereza C Vessoni

2010-01-01

36

Modification of poly(glycidyl methacrylate–divinylbenzene) porous microspheres with polyethylene glycol and their adsorption property of protein  

Microsoft Academic Search

Rigid porous poly(glycidyl methacrylate–divinylbenzene) (P(GMA–DVB)) microspheres were synthesized through suspension polymerization with a mixture of isooctane and 4-methyl-2-pentonal as the porogen. The microspheres were intended to use as column packing materials for protein separation. However, irreversible adsorption of protein was found on the polymer microsphere. To circumvent the problem, polyethylene glycol (PEG) was coupled to the microspheres. The coupling reaction

Renwei Wang; Ying Zhang; Guanghui Ma; Zhiguo Su

2006-01-01

37

Preparation and properties of electrospun soy protein isolate/polyethylene oxide nanofiber membranes.  

PubMed

Soy protein isolate (SPI) and polyethylene oxide (PEO) were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and nonwoven nanofiber membranes were prepared from the solution by electrospinning. PEO functioned as a cospinning polymer in the process to improve the spinnability of SPI. The ratio of SPI to PEO was varied and the rest spinning conditions remained unchanged. The morphology of the nanofiber membranes, SPI and PEO distribution and phase structure in the fiber, crystallization and interaction between SPI and PEO, thermal properties and wettability of the membranes were studied. The results showed that the diameter of most of the nanofibers was in the range of 200-300 nm. SPI and PEO showed high compatibility in the fiber and SPI was homogeneously dispersed at nanoscale. Crystallization of SPI and PEO in the fiber was significantly different from that of their pure forms. All the nanofiber membranes showed superhydrophilicity. These nanofiber membranes can find importance in filtration and biomedical applications. PMID:22839659

Xu, Xuezhu; Jiang, Long; Zhou, Zhengping; Wu, Xiangfa; Wang, Yechun

2012-08-01

38

Poly(ethylene glycol) hydrogels formed by conjugate addition with controllable swelling, degradation, and release of pharmaceutically active proteins  

Microsoft Academic Search

Hydrogels were formed by conjugate addition of polyethylene glycol (PEG) multiacrylates and dithiothreitol (DTT) for encapsulation and sustained release of protein drugs; human growth hormone (hGH) was considered as an example. Prior to encapsulation, the hGH was precipitated either by Zn2+ ions or by linear PEG, to protect the hGH from reaction with the gel precursors during gelation. Precipitation by

Petra van de Wetering; Andrew T. Metters; Ronald G. Schoenmakers; Jeffrey A. Hubbell

2005-01-01

39

Monoliths from poly(ethylene glycol) diacrylate and dimethacrylate for capillary hydrophobic interaction chromatography of proteins  

Microsoft Academic Search

Rigid monoliths were synthesized solely from poly(ethylene glycol) diacrylates (PEGDA) or poly(ethylene glycol) dimethacrylates (PEGDMA) containing different ethylene glycol chain lengths by one-step UV-initiated polymerization. Methanol\\/ethyl ether and cyclohexanol\\/decanol were used as bi-porogen mixtures for the PEGDA and PEGDMA monoliths, respectively. Effects of PEG chain length, bi-porogen ratio and reaction temperature on monolith morphology and back pressure were investigated. For

Yuanyuan Li; H. Dennis Tolley; Milton L. Lee

2010-01-01

40

Effect of salt additives on protein partition in polyethylene glycol-sodium sulfate aqueous two-phase systems.  

PubMed

Partitioning of 15 proteins in polyethylene glycol (PEG)-sodium sulfate aqueous two-phase systems (ATPS) formed by PEG of two different molecular weights, PEG-600 and PEG-8000 in the presence of different buffers at pH7.4 was studied. The effect of two salt additives (NaCl and NaSCN) on the protein partition behavior was examined. The salt effects on protein partitioning were analyzed by using the Collander solvent regression relationship between the proteins partition coefficients in ATPS with and without salt additives. The results obtained show that the concentration of buffer as well as the presence and concentration of salt additives affects the protein partition behavior. Analysis of ATPS in terms of the differences between the relative hydrophobicity and electrostatic properties of the phases does not explain the protein partition behavior. The differences between protein partitioning in PEG-600-salt and PEG-8000-salt ATPS cannot be explained by the protein size or polymer excluded volume effect. It is suggested that the protein-ion and protein-solvent interactions in the phases of ATPS are primarily important for protein partitioning. PMID:23920121

Ferreira, Luisa; Madeira, Pedro P; Mikheeva, Larissa; Uversky, Vladimir N; Zaslavsky, Boris

2013-12-01

41

Protein repellent polyurethane-urea surfaces by chemical grafting of hydroxyl-terminated poly(ethylene oxide): effects of protein size and charge  

Microsoft Academic Search

The objective of this work was to elucidate the mechanism of protein repellency by surfaces grafted with poly(ethylene oxide) (PEO). Surfaces were prepared by chemical grafting to polyurethane-urea films. Free isocyanate groups were first introduced into the surface and then reacted with hydroxyl-terminated PEO. The chain length of the grafted PEO was varied from 3 to 113 ethylene oxide units.

Jacques G Archambault; John L Brash

2004-01-01

42

Novel monolithic materials using poly(ethylene glycol) as porogen for protein separation  

Microsoft Academic Search

Several recipes are described for the preparation of porous polymeric monoliths in the capillary format, using poly(ethylene glycol) (PEG) as porogen as well as constituent in the monomer mixture. Acrylic or methacrylic monomers with a variety of terminal groups, with and without ethylene glycol links of differing lengths in the side chains, have been used in combination with triethylene glycol

Julien Courtois; Emil Byström; Knut Irgum

2006-01-01

43

Protein adsorption and cell adhesion on nanoscale bioactive coatings formed from poly(ethylene glycol) and albumin microgels  

PubMed Central

Late-term thrombosis on drug-eluting stents is an emerging problem that might be addressed using extremely thin, biologically-active hydrogel coatings. We report a dip-coating strategy to covalently link poly(ethylene glycol) (PEG) to substrates, producing coatings with protein-resistant layer with a thickness of approximately 75 nm. Atomic force microscopy in buffered water revealed the presence of coalesced spheres of various sizes but with diameters less than about 100 nm. Microgel-coated glass or poly(ethylene terephthalate) exhibited reduced protein adsorption and cell adhesion. Cellular interactions with the surface could be controlled by using different proteins to cap unreacted vinylsulfone groups within the coating.

Scott, Evan A.; Nichols, Michael D.; Cordova, Lee H.; George, Brandon J.; Jun, Young-Shin; Elbert, Donald L.

2008-01-01

44

Grafted poly-(ethylene glycol) on lipid surfaces inhibits protein adsorption and cell adhesion  

Microsoft Academic Search

Monolayers of dipalmitoyl-phosphatidylethanolamine (DPPE) mixing with various mole percentages of distearoyl-phosphatidylethanolamine (DSPE)-conjugated poly-(ethylene glycol) (PEG m.w. 750–5000) were deposited on DPPE-coated glass surfaces by the Langmuir-Blodgett method. Increasing percentages of grafted PEG in these supported lipid surfaces increasingly inhibit the adsorption of bovine serum albumin (BSA), laminin, and fibronectin. Increasing percentages of grafted PEG also inhibit the adhesion of erythrocytes,

Hong Du; Parthapratim Chandaroy; Sek Wen Hui

1997-01-01

45

Protein partitioning in poly(ethylene glycol)\\/sodium polyacrylate aqueous two-phase systems  

Microsoft Academic Search

The partition of hemoglobin, lysozyme and glucose-6-phospate dehydrogenase (G6PDH) in a novel inexpensive aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The effect of NaCl and Na2SO4, pH and PEG molecular size on the partitioning has been studied. At high pH (above 9), hemoglobin partitions strongly to the PEG-phase. Although some precipitation

Hans-Olof Johansson; Flavio Musa Magaldi; Eloi Feitosa; Adalberto Pessoa

2008-01-01

46

Protein adsorption on well-characterized polyethylene oxide brushes on gold: dependence on molecular weight and grafting density.  

PubMed

The adsorption of lysozyme protein was measured ex situ on well-characterized gold surfaces coated by end-tethered polyethylene oxide brushes of various molecular weights and controlled grafting densities. The adsorbed amount of protein for different molecular weight brushes was found to collapse onto one master curve when plotted against brush coverage. We interpret this relationship in terms of a model involving site-blocking of the adsorption of proteins at the substrate and discuss the role of the physical attraction of PEO segments to gold. We account for our observation of a simple exponential relationship between protein adsorption and normalized brush coverage with a simple protein adsorption model. In contrast to other studies in similar systems, we do not observe protein adsorption on brushes at high grafting density, and we suggest that this discrepancy may be due to the solubility effects of salt upon the brushes, influencing their protein binding affinity, in the limit of high grafting density and high brush volume fraction. PMID:23617308

Taylor, Warren; Jones, Richard A L

2013-05-21

47

Intermolecular Interactions Between Proteins and Individual Poly(ethylene oxide) Chains Measured via High-Resolution Force Spectroscopy  

NASA Astrophysics Data System (ADS)

The noncovalent adsorption of biofluid proteins onto biomaterial surface coatings, such as poly(ethylene oxide) (PEO), is known to be a primary determining factor of biocompatibility. The molecular mechanisms and precise details of the nanoscale forces acting between proteins and synthetic surface polymers are complex and poorly understood. We have directly measured the intermolecular interaction forces in aqueous buffer solution between individual end-grafted PEO chains and a probe tip covalently bound with human serum albumin (HSA) using high-resolution force spectroscopy. Long-range adhesion is frequently observed between the HSA probe tip and the PEO chain on retraction, which is strong enough to allow stretching of the individual PEO chains (Fadhesion=0.125nN±0.22nN, Dadhesion=246nm±148nm). Statistical analysis, comparison to a variety of control experiments, and theoretical modeling enable us to interpret these experimental results in terms of electrostatic, hydrogen, and steric interactions.

Ortiz, Christine; Rixman, Monica

2002-03-01

48

Capillary isoelectric focusing and fluorometric detection of proteins and microorganisms dynamically modified by poly(ethylene glycol) pyrenebutanoate.  

PubMed

The nonionogenic pyrene-based tenside, poly(ethylene glycol) pyrenebutanoate, was prepared and applied in capillary isoelectric focusing with fluorometric detection. This dye was used here as a buffer additive in capillary isoelectric focusing for a dynamic modification of the sample of proteins and microorganisms. The values of the isoelectric points of the labeled bioanalytes were calculated with use of the fluorescent pI markers and were found comparable with pI of the native compounds. The mixed cultures of proteins and microorganisms, Escherichia coli CCM 3954, Staphylococcus epidermidis CCM 4418, Proteus vulgaris, Enterococcus faecalis CCM 4224, and Stenotrophomonas maltophilia, the strains of the yeast cells, Candida albicans CCM 8180, Candida krusei, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae were reproducibly focused and separated by the suggested technique. Using UV excitation for the on-column fluorometric detection, the minimum detectable amount was down to 10 cells injected on the separation capillary. PMID:17165837

Horka, Marie; Ruzicka, Filip; Horký, Jaroslav; Holá, Veronika; Slais, Karel

2006-12-15

49

Microcontact printing and microspotting as methods for direct protein patterning on plasma deposited polyethylene oxide: application to stem cell patterning.  

PubMed

Two methods for protein patterning on antifouling surfaces have been applied to analyze the density and bioactivity of the proteins after deposition. Microcontact printing has been used as a technique to transfer fibronectin through conformal contact, while piezoelectric deposition has been employed as a non-contact technique for producing arrays of fibronectin (FN). Plasma deposited polyethylene oxide-like (PEO-like) films have been used as non-fouling background to achieve the bioadhesive/biorepellent surface contrast. Both patterning methods allow the direct fabrication of protein arrays on a non-fouling substrate, and the subsequent formation of a pattern of stem cells by cell attachment on the arrayed substrates. Microcontact printing produced fully packed homogeneous fibronectin patterns, much denser than microspotted patterns. Both printing and spotting technologies generated functional protein arrays, their bioactivity being primarily modulated by the density of the deposited protein layer. Optimization of the FN parameters used for deposition has lead to the achievement of high-quality microarrays with large population of neural stem cells immobilized in the patterns in serum-free conditions, where cells exhibit a more homogeneous starting population and factors influencing fate decisions can be more easily tracked. The immunorecognition of fibronectin targeted antibodies, as well as the cell density, increase with the protein density up to a saturation point. Over 100 ng/cm² of fibronectin on the surface leads to a decrease in the number of attached cells and a raise of cell spreading. PMID:23404262

Ruiz, Ana; Zychowicz, Marzena; Ceriotti, Laura; Mehn, Dora; Sirghi, Lucel; Rauscher, Hubert; Mannelli, Ilaria; Colpo, Pascal; Buzanska, Leonora; Rossi, François

2013-06-01

50

Modification of gold surface by grafting of poly(ethylene glycol) for reduction in protein adsorption and platelet adhesion.  

PubMed

Gold surfaces were first treated in an alkanethiol solution to form self-assembled monolayers (SAMs). The thiolated Au surface was then subjected to Ar plasma pretreatment, followed by air exposure and UV-induced graft polymerization of poly(ethylene glycol) methacrylate (PEGMA) macromonomer. In comparison with the 3-mercaptopropionic acid-2-ethylhexyl ester (MPAEE) SAM, the (3-mercaptoproply)trimethoxysilane (MPTMS) SAM on Au exhibited higher stability under the conditions of Ar plasma pretreatment. The graft concentration of the PEGMA polymer on SAM-modified Au surface increased with increasing PEGMA macromonomer concentration and UV-graft polymerization time. The modified-Au surfaces were characterized by X-ray spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle measurement. The Au surface with a high concentration of grafted PEGMA polymer could completely repel protein adsorption and platelet adhesion. PMID:11469782

Zhang, F; Kang, E T; Neoh, K G; Huang, W

2001-01-01

51

Reactive coupling of poly(ethylene glycol) on electroactive polyaniline films for reduction in protein adsorption and platelet adhesion.  

PubMed

Poly(ethylene glycol) (PEG)-coupled polyaniline (PANI) film surfaces were prepared by incorporating the chlorinie end-capped methoxy PEG (mPEGCl) of molecular weight of about 2000 onto the emeraldine (EM) base form of PANI via N-alkylation. The microstructure and composition of the mPEG-coupled PANI (mPEG-c-PANI) surfaces were characterized by atomic force microscopy, contact angle measurement and X-ray photoelectron spectroscopy. The concentration of surface-coupled mPEG increased with the increase in concentration of the mPEGCl solution. The mPEG-c-PANI film surfaces exhibited enhanced ability to repel protein adsorption, with only an moderate reduction in their electrical conductivity. The mPEG-c-PANI surface with a high concentration of coupled mPEG also exhibited good resistance towards platelet adhesion. PMID:11771698

Zhang, Fu; Kang, E T; Neoh, K G; Wang, Peng; Tan, K L

2002-02-01

52

Wear properties of polyethylene-metal and polyethylene-ceramic bearings for hip joint replacements: The effect of temperature and protein precipitation in hip simulator tests  

Microsoft Academic Search

Ultra-high-molecular weight polyethylene (PE) cups bearing against metal or ceramic balls are the most commonly used combinations of materials for human hip joint replacements. The wear properties of these materials are typically evaluated in the laboratory using hip joint wear simulators, while lubricated with bovine serum. A previous test evaluating the PE cups against cobalt-chrome (CoCr), zirconia (Zr) and alumina

Yen-Shuo Liao

1999-01-01

53

Mechanical and microstructural properties of hybrid poly(ethylene glycol)-soy protein hydrogels for wound dressing applications.  

PubMed

Biomimetic hydrogel made of poly(ethylene glycol) and soy protein with a water content of 96% has been developed for moist wound dressing applications. In this study, such hybrid hydrogels were investigated by both tensile and unconfined compression measurements in order to understand the relationships between structural parameters of the network, its mechanical properties and protein absorption in vitro. Elastic moduli were found to vary from 1 to 17 kPa depending on the composition, while the Poisson's ratio (approximately 0.18) and deformation at break (approximately 300%) showed no dependence on this parameter. Further calculations yielded the crosslinking concentration, the average molecular weight between crosslinks (M(C)) and the mesh size. The results show that reactions between PEG and protein create polymeric chains comprising molecules of PEG and protein fragments between crosslinks. M(C) is three times higher than that expected for a "theoretical network." On the basis of this data, we propose a model for the 3D network of the hydrogel, which is found to be useful for understanding drug release properties and biomedical potential of the studied material. PMID:17380500

Snyders, Rony; Shingel, Kirill I; Zabeida, Oleg; Roberge, Christophe; Faure, Marie-Pierre; Martinu, Ludvik; Klemberg-Sapieha, Jolanta E

2007-10-01

54

Protein partitioning in poly(ethylene glycol)/sodium polyacrylate aqueous two-phase systems.  

PubMed

The partition of hemoglobin, lysozyme and glucose-6-phosphate dehydrogenase (G6PDH) in a novel inexpensive aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The effect of NaCl and Na(2)SO(4), pH and PEG molecular size on the partitioning has been studied. At high pH (above 9), hemoglobin partitions strongly to the PEG-phase. Although some precipitation of hemoglobin occurs, high recovery values are obtained particularly for lysozyme and G6PDH. The partitioning forces are dominated by the hydrophobic and electrochemical (salt) effects, since the positively charged lysozyme and negatively charged G6PDH partitions to the non-charged PEG and the strongly negatively charged polyacrylate enriched phase, respectively. PMID:18078945

Johansson, Hans-Olof; Magaldi, Flavio Musa; Feitosa, Eloi; Pessoa, Adalberto

2008-01-18

55

Polyethylene oxide surfaces of variable chain density by chemisorption of PEO-thiol on gold: Adsorption of proteins from plasma studied by radiolabelling and immunoblotting  

Microsoft Academic Search

The mechanisms involved in the inhibition of protein adsorption by polyethylene oxide (PEO) are not completely understood, but it is believed that PEO chain length, chain density and chain conformation all play a role. In this work, surfaces formed by chemisorption of PEO-thiol to gold were investigated: the effects of PEO chain density, chain length (600, 750, 2000 and 5000MW)

Larry D. Unsworth; Heather Sheardown; John L. Brash

2005-01-01

56

Surface modification of ultrahigh molecular weight polyethylene by the poly(ethylene glycol)-grafted method and its effect on the adsorption of proteins and the adhesion of blood platelets.  

PubMed

With the help of a silane coupling agent, poly(ethylene glycol) (PEG), a well-biocompatable agent, was grafted onto the surface of ultrahigh molecular weight polyethylene (UHMWPE) by ultraviolet initiation. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis proved the success of PEG grafting. Water contact angle measurement showed that the modified UHMWPE was obviously improved in surface hydrophilicity and thermogravimetric analysis result showed that its thermostability did not decline even it was pretreated by strong acids. Then, the protein adsorption of the modified UHMWPE was investigated using three model proteins including bovine serum albumin, lysozyme, and fibrinogen. Rabbit blood was used to study the platelet adhesion on the surface of modified UHMWPE. The results indicated that the quantity of protein adsorption on the modified UHMWPE grafted PEG reduced apparently for all the model proteins while there was some specific differences or exceptions among them. It was ascribed to the changed surface chemical composition, surface hydrophilicity and surface topography after modification. The adhesive ability of blood platelets on the modified surface of UHMWPE decreased after PEG grafting. Owing to the improved resistance to fibrinogen adsorption and platelet adhesion, the surface modification might endow the UHWMPE surface better anticoagulation ability according to clotting mechanism. PMID:22807149

Xia, Bing; Xie, Meiju; Yang, Bangcheng

2013-01-01

57

Using poly(ethylene glycol) silane to prevent protein adsorption in microfabricated silicon channels  

NASA Astrophysics Data System (ADS)

Microfluidic devices fabricated in silicon are quickly finding use in many areas of technology. Exploration of new applications of this technology has shown both advantages and disadvantages to extreme miniaturization of chemical assays. While accuracy, efficiency and smaller sample volumes are among the advantages, interactions between the walls of the micro-channels and the fluid or particles it contains are among the disadvantages. Our group is applying this technology to chemical and biological warfare (CBW) agent purification and detection. We present preliminary result towards achieving a long-term antifouling surface in our detection system. A microfluidic device was anisotropically etched in a (100) silicon wafer and attached to a Pyrex glass slip to create an enclosed channel. Poly(ethylene glycol) (PEG) silane was covalently bonded to the hydroxyls of an oxide layer on the silicon device and the Pyrex cover slip. Fluorescently labeled ovalbumin, a CBW simulant, was in contact with an unmodified and PEG-modified channel. The extent of adsorption was determined using fluorescence microscopy.

Bell, Darrel J.; Brody, James P.; Yager, Paul

1998-03-01

58

Oxygen-rich coating promotes binding of proteins and endothelialization of polyethylene terephthalate polymers.  

PubMed

The formation of endothelial cell monolayer on prosthetic implants has not sufficiently explored. The main reasons leading to the development of thrombosis and/or intimal hyperplasia is the lack of endothelialization. In the present work, we have studied the influence of oxygen and fluorine plasma treatment of polyethylene terephthalate (PET) polymers on human microvascular endothelial cell adhesion and proliferation. We characterized the polymer surface, wettability, and oxidation potential upon plasma treatment. Moreover, binding of serum and media compounds on PET surface was monitored by Quartz crystal microbalance method, X-ray photoelectron spectroscopy, and atomic force microscopy. Cell adhesion and morphology was assessed by light and scanning electron microscopy. The influence of plasma treatment on induction of cellular oxidative stress and cell proliferation was evaluated. The results obtained showed that treatment with oxygen plasma decreased the oxidation potential of the PET surface and revealed the highest affinity for binding of serum components. Accordingly, the cells reflected the best adhesion and morphological properties on oxygen-treated PET polymers. Moreover, treatment with oxygen plasma did not induce intracellular reactive oxygen species production while it stimulated endothelial cell proliferation by 25% suggesting the possible use of oxygen plasma treatment to enhance endothelialization of synthetic vascular grafts. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2305-2314, 2014. PMID:23946257

Jaganjac, Morana; Vesel, Alenka; Milkovic, Lidija; Recek, Nina; Kolar, Metod; Zarkovic, Neven; Latiff, Aishah; Kleinschek, Karin-Stana; Mozetic, Miran

2014-07-01

59

Morphology and Properties of Deoiled Cake (DOC) Isolated Mixed Proteins and Low-Density Polyethylene Blends  

Microsoft Academic Search

Proteins were isolated from deoiled cakes (DOC) of soybean, castor and rapeseed. The isolated proteins were then blended with LDPE in different wt. ratios, using PEG400 as a plasticizer. The morphology of the blends was evaluated by using a scanning electron microscope (SEM). Homogeneous blends were obtained and analyzed for various mechanical properties such as tensile strength, impact strength, hardness

Darshan Patel; S. D. Toliwal; J. V. Patel

2012-01-01

60

Protein encapsulation into biodegradable microspheres by a novel S/O/W emulsion method using poly(ethylene glycol) as a protein micronization adjuvant.  

PubMed

A new method for preparing protein-loaded biodegradable microspheres by a process involving solid-in-oil-in-water (S/O/W) emulsion was established using poly(ethylene glycol) (PEG). In the first step, a protein solution was lyophilized with PEG, which resulted in the formation of spherical protein microparticles, less than 5 microm in diameter, dispersed in a continuous PEG phase. This process was well explained by the aqueous phase separation phenomenon induced by freezing-condensation. Since this lyophilizate could be directly dispersed in an organic phase containing biodegradable polymer by dissolving PEG with methylene chloride, a conventional in-water drying method could be adopted in the second step. Through this S/O/W emulsion process, horseradish peroxidase was effectively entrapped into monolithic-type microspheres of poly(DL-lactic-co-glycolic acid) (PLGA), without significant loss of activity. Bovine superoxide dismutase (bSOD), as another model protein, could be encapsulated into reservoir-type microspheres by the 'polymer-alloys method' using both poly(DL-lactic acid) (PLA) and PLGA. The initial release of bSOD from this reservoir-type microsphere was efficiently reduced. Further, the bSOD release kinetics could be suitably modified by adjusting the loading amounts of PEG or polymer composition. In this study, the multi-functional nature of PEG was successfully utilized in the preparation and designing of protein-loaded microspheres. PMID:11102683

Morita, T; Sakamura, Y; Horikiri, Y; Suzuki, T; Yoshino, H

2000-12-01

61

Short communication: renal tubular vacuolation in animals treated with polyethylene-glycol-conjugated proteins.  

PubMed

During toxicologic evaluation of a dimeric PEG-linked protein, tumor necrosis factor binding protein (TNF-bp), vacuolation of renal cortical tubular epithelium was seen in male and female Sprague-Dawley rats (200-300 g) given i.v. doses of 40, 20, or 10 mg/kg every other day for 3 months. Tubular lesions in rats treated with 20 or 40 mg/kg for 3 months were only partially reversible after a 2-month recovery period. Despite the presence of marked vacuolation, there were no changes in BUN, creatinine, urinalysis parameters, urinary NAG, urinary B2-microglobulin, or fractional sodium excretion. Single i.v. doses > or = 20 mg/kg TNF-bp caused similar but milder changes. However, equivalent doses of PEG alone or the non-PEG-linked TNF-bp did not cause light microscopic evidence of vacuolation. Treatment of rats with another PEG-linked protein of similar molecular weight resulted in similar changes. Immunostaining for TNF-bp revealed positivity in the apical cytoplasm of renal tubular epithelium within 1 h of i.v. dosing. Immunostaining of kidneys from chronically dosed rats indicated that protein was present in some vacuoles as long as dosing continued; however, kidneys from animals on a reversibility study had vacuoles but no immunostaining for TNF-bp. These results, along with a study that showed more severe lesions with PEG-linked proteins of lower molecular weight and minimal if any lesions with PEG-linked proteins > 70 kDa, suggest that TNF-bp is filtered through the glomerulus and that the protein with attached PEG is reabsorbed by the proximal tubules. Vacuolation may be a result of fluid distension of lysosomes due to the hygroscopic nature of PEG. These studies demonstrated that PEG-linked proteins have the capacity to induce renal tubular vacuolation at high doses. However, the change was not associated with alteration of clinical pathology or functional markers. PMID:9579027

Bendele, A; Seely, J; Richey, C; Sennello, G; Shopp, G

1998-04-01

62

Pharmacokinetic and biodistribution properties of poly(ethylene glycol)–protein conjugates  

Microsoft Academic Search

Peptide and protein PEGylation is usually undertaken to improve the biopharmaceutical properties of these drugs and, to date, several examples of conjugates with long permanence in the body as well as with localization ability in disease sites have been reported. Although a number of studies on the in vivo behavior and fate of conjugates have been performed, forecasting their pharmacokinetics

Paolo Caliceti; Francesco M. Veronese

2003-01-01

63

Covalent conjugation of poly(ethylene glycol) to proteins and peptides: strategies and methods.  

PubMed

PEGylation, the covalent linking of PEG chains, has become the leading drug delivery approach for proteins. This technique initiated its first steps almost 40 years ago, and since then, a variety of methods and strategies for protein-polymer coupling have been devised. PEGylation can give a number of relevant advantages to the conjugated protein, such as an important in vivo half-life prolongation, a reduction or an abolishment of immunogenicity, and a reduction of aggregation. Furthermore, the technique has demonstrated a great degree of versatility and efficacy--not only PEG-protein conjugates have reached the commercial marketplace (with nine types of derivatives), but a PEG-aptamer and PEGylated liposomes are now also available. Most of this success is due to the development of several PEGylation strategies and to the large selection of PEGylating agents presently at hand for researchers. Nevertheless, this technique still requires a certain level of familiarity and knowledge in order to achieve a positive outcome for a PEGylation project. To draw general guidelines for conducting PEGylation studies is not always easy or even possible because such experiments often require case-by-case optimization. On the other hand, several common methods can be used as starting examples for the development of tailor-made coupling conditions. Therefore, this chapter aims to provide a basic introduction to a wide range of PEGylation procedures for those researchers who may not be familiar with this field. PMID:21674328

Mero, Anna; Clementi, Chiara; Veronese, Francesco M; Pasut, Gianfranco

2011-01-01

64

Inflammatory inert poly(ethylene glycol)--protein wound dressing improves healing responses in partial- and full-thickness wounds.  

PubMed

In this study, a novel soft hydrogel system based on the poly(ethylene glycol)-protein conjugates was evaluated as an occlusive wound dressing material. The hydrogel material, referred by the name of BioAquacare, contains up to 96% of the liquid and is formulated with phosphate-buffered saline and safe preservative to control bacterial load in the open wounds. Performance of the BioAquacare as a wound dressing material was assessed in partial- and full-thickness wounds in pigs. Wound analysis comprised macroscopic determination of the wound size, histological examination of the healing tissues and biochemical characterisation of wound exudates. The wounds treated with BioAquacare healed without any signs of inflammation, skin irritation, oedema or erythema. Cellular composition of the reepithelialised wounds was very similar to that of the normal skin, with a well-developed stratum corneum and epithelial layer. It was observed that BioAquacare plays the role of a liquid compartment, which provides pronounced hydration effect and helps maintain a natural moist environment of the healing tissues. BioAquacare showed relatively low protein-absorbing activity, absorbing predominantly low-molecular-weight molecules, including interleukin (IL)-1beta, IL-6, transforming growth factor-beta1 and products of haemoglobin degradation. It is concluded that application of the moist BioAquacare dressing promotes fast reepithelialisation by creating favourable environment for keratinocytes proliferation and it also reduces scarring. The results show that BioAquacare can be considered as a safe, biocompatible and inflammatory inert wound dressing material. PMID:17199768

Shingel, Kirill I; Di Stabile, Liliana; Marty, Jean-Paul; Faure, Marie-Pierre

2006-12-01

65

The influence of poly(ethylene oxide) grafting via siloxane tethers on protein adsorption  

Microsoft Academic Search

Amphiphilic PEO–silanes (a–c) having siloxane tethers of varying lengths with the general formula ?-(EtO)3Si–(CH2)2–oligodimethylsiloxanen-block-poly(ethylene oxide)8–OCH3 [n=0 (a), n=4 (b), and n=13 (c)] were grafted onto silicon wafers and resistance to adsorption of plasma proteins was measured. Distancing the PEO segment from the hydrolyzable triethoxysilane [(EtO)3Si] grafting group by a oligodimethylsiloxane tether represents a new method of grafting PEO chains to

Ranjini Murthy; Courtney E. Shell; Melissa A. Grunlan

2009-01-01

66

A new approach to the immobilisation of poly(ethylene oxide) for the reduction of non-specific protein adsorption on conductive substrates  

NASA Astrophysics Data System (ADS)

Biomedical and biotechnological devices often require surface modifications to improve their performance. In most cases, uniform coatings are desired which provide a specific property or lead to a specific biological response. In the present work, we have generated pinhole-free coatings providing amine functional groups achieved by electropolymerisation of tyramine on highly doped silicon substrates. Furthermore, amine groups were used for the subsequent grafting of poly(ethylene oxide) aldehyde via reductive amination. All surface modification steps were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results indicate that the stability and the density of amine functional groups introduced at the surface via electropolymerisation compare favourably with alternative coatings frequently used in biomedical and biotechnological devices such as plasma polymer films. Furthermore, protein adsorption on amine and poly(ethylene oxide) coatings was studied by XPS and a colorimetric assay to test enzymatic activity. The grafting of poly(ethylene oxide) under cloud point conditions on electropolymerised tyramine layers resulted in surfaces with extremely low protein fouling character.

Cole, Martin A.; Thissen, Helmut; Losic, Dusan; Voelcker, Nicolas H.

2007-04-01

67

Separation of positional isomers of mono-poly(ethylene glycol)-modified octreotides by reversed-phase high-performance liquid chromatography  

Microsoft Academic Search

The purpose of this study was to develop a reversed-phase high-performance liquid chromatographic method (RP-HPLC) for separating each positional isomer from low- to high-molecular-weight mono-PEGylated octreotides prepared by polyethylene glycol (PEG) derivatives with various molecular weights (2, 5, or 20kDa). In the gradient elution using acetonitrile and 10mM phosphate buffer at pH 7.0 on a Phenomenex Gemini C-18 column (250mm×4.6mm

Eun Ji Park; Kang Choon Lee; Dong Hee Na

2009-01-01

68

POLYETHYLENE ENCAPSULATION  

Microsoft Academic Search

Polyethylene microencapsulation physically homogenizes and incorporates mixed waste particles within a molten polymer matrix, forming a solidified final waste form upon cooling. Each individual particle of waste is embedded within the polymer block and is surrounded by a durable, leach-resistant coating. The process has been successfully applied for the treatment of a broad range of mixed wastes, including evaporator concentrate

2001-01-01

69

Graft copolymer-templated mesoporous TiO(2) films micropatterned with poly(ethylene glycol) hydrogel: novel platform for highly sensitive protein microarrays.  

PubMed

In this study, we describe the use of organized mesoporous titanium oxide (TiO(2)) films as three-dimensional templates for protein microarrays with enhanced protein loading capacity and detection sensitivity. Multilayered mesoporous TiO(2) films with high porosity and good connectivity were synthesized using a graft copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly(oxyethylene methacrylate) (POEM) side chains as a structure-directing template. The average pore size and thickness of the TiO(2) films were 50-70 nm and 1.5 ?m, respectively. Proteins were covalently immobilized onto mesoporous TiO(2) film via 3-aminopropyltriethoxysilane (APTES), and protein loading onto TiO(2) films was about four times greater than on planar glass substrates, which consequently improved the protein activity. Micropatterned mesoporous TiO(2) substrates were prepared by fabricating poly(ethylene glycol) (PEG) hydrogel microstructures on TiO(2) films using photolithography. Because of non-adhesiveness of PEG hydrogel towards proteins, proteins were selectively immobilized onto surface-modified mesoporous TiO(2) region, creating protein microarray. Specific binding assay between streptavidin/biotin and between PSA/anti-PSA demonstrated that the mesoporous TiO(2)-based protein microarrays yielded higher fluorescence signals and were more sensitive with lower detection limits than microarrays based on planar glass slides. PMID:21291203

Son, Kyung Jin; Ahn, Sung Hoon; Kim, Jong Hak; Koh, Won-Gun

2011-02-01

70

POLYETHYLENE ENCAPSULATION.  

SciTech Connect

Polyethylene microencapsulation physically homogenizes and incorporates mixed waste particles within a molten polymer matrix, forming a solidified final waste form upon cooling. Each individual particle of waste is embedded within the polymer block and is surrounded by a durable, leach-resistant coating. The process has been successfully applied for the treatment of a broad range of mixed wastes, including evaporator concentrate salts, soil, sludges, incinerator ash, off-gas blowdown solutions, decontamination solutions, molten salt oxidation process residuals, ion exchange resins, granular activated carbon, shredded dry active waste, spill clean-up residuals, depleted uranium powders, and failed grout waste forms. For waste streams containing high concentrations of soluble toxic metal contaminants, additives can be used to further reduce leachability, thus improving waste loadings while meeting or exceeding regulatory disposal criteria. In this configuration, contaminants are both chemically stabilized and physically solidified, making the process a true stabilization/solidification (S/S) technology. Unlike conventional hydraulic cement grouts or thermosetting polymers, thermoplastic polymers such as polyethylene require no chemical. reaction for solidification. Thus, a stable, solid, final waste form product is assured on cooling. Variations in waste chemistry over time do not affect processing parameters and do not require reformulation of the recipe. Incorporation of waste particles within the polymer matrix serves as an aggregate and improves the mechanical strength and integrity of the waste form. The compressive strength of polyethylene microencapsulated waste forms varies based on the type and quantity of waste encapsulated, but is typically between 7 and 17.2 MPa (1000 and 2500 psi), well above the minimum strength of 0.4 MPa (160 psi) recommended by the U.S. Nuclear Regulatory Commission (NRC) for low-level radioactive waste forms in support of 10 CFR 61 (NRC, 1991; 1983) Because polyethylene is a relatively new material, it is difficult to predict its long-term durability. However, prior to scale-up of the microencapsulation process, a study was conducted to evaluate potential degradation mechanisms. The study examined potential effects on mechanical integrity from exposure to chemicals and solvents, thermal cycling, saturated environments, microbial attack, and high gamma-radiation fields (Kalb et al., 1991). At ambient temperatures, polyethylene is relatively inert to most chemicals, including organic solvents, acids, and alkaline solutions. Exposure to changes in temperature or saturated soil conditions have been shown to degrade the mechanical integrity of some waste forms, but had little or no measurable impact on polyethylene waste forms. Low-density polyethylene is not susceptible to growth of microbial organisms, a fact that is evidenced by the lack of plastics decomposition in municipal waste landfills. When exposed to gamma-radiation at total doses of up to lo8 rad, additional cross-linking of the polymer occurs, resulting in increased strength and lower leachability.

KALB, P.

2001-08-22

71

Surface modification of poly(tetrafluoroethylene) films via grafting of poly(ethylene glycol) for reduction in protein adsorption.  

PubMed

Poly(tetrafluoroethylene) (PTFE) films with surface grafted poly(ethylene glycol) (PEG) chains were prepared by two methods: (1) UV-induced graft copolymerization of methoxy poly- (ethylene glycol) monomethacrylate (PEGMA) onto the plasma-pretreated PTFE films; and (2) coupling of the hydroxyl groups of PEG via ester linkages with the carbonyl chloride groups which were introduced onto the acrylic acid (AAc) graft-copolymerized PTFE surface through reaction with thionyl chloride (SOCl2). The UV-induced graft copolymerization of PEGMA onto the plasma-pretreated PTFE film was explored with different macromonomer concentrations and different UV graft copolymerization time. The coupling reaction, on the other hand, was explored with PEG of different molecular weights. The surface microstructures and compositions of the PEG-modified PTFE films from both processes were characterized by contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) measurements. In general, higher macromonomer concentration and longer UV graft copolymerization time led to a higher graft yield for the UV-induced graft copolymerization with PEGMA. Contact angle measurements revealed that the hydrophilicity of the PTFE film surface was greatly enhanced by the grafting of the PEG chains. The PTFE surface with a high density of grafted PEG was very effective in preventing bovine serum albumin adsorption. PMID:10718477

Wang, P; Tan, K L; Kang, E T

2000-01-01

72

Two novel class II hydrophobins from Trichoderma spp. stimulate enzymatic hydrolysis of poly(ethylene terephthalate) when expressed as fusion proteins.  

PubMed

Poly(ethylene terephthalate) (PET) can be functionalized and/or recycled via hydrolysis by microbial cutinases. The rate of hydrolysis is however low. Here, we tested whether hydrophobins (HFBs), small secreted fungal proteins containing eight positionally conserved cysteine residues, are able to enhance the rate of enzymatic hydrolysis of PET. Species of the fungal genus Trichoderma have the most proliferated arsenal of class II hydrophobin-encoding genes among fungi. To this end, we studied two novel class II HFBs (HFB4 and HFB7) of Trichoderma. HFB4 and HFB7, produced in Escherichia coli as fusions to the C terminus of glutathione S-transferase, exhibited subtle structural differences reflected in hydrophobicity plots that correlated with unequal hydrophobicity and hydrophily, respectively, of particular amino acid residues. Both proteins exhibited a dosage-dependent stimulation effect on PET hydrolysis by cutinase from Humicola insolens, with HFB4 displaying an adsorption isotherm-like behavior, whereas HFB7 was active only at very low concentrations and was inhibitory at higher concentrations. We conclude that class II HFBs can stimulate the activity of cutinases on PET, but individual HFBs can display different properties. The present findings suggest that hydrophobins can be used in the enzymatic hydrolysis of aromatic-aliphatic polyesters such as PET. PMID:23645195

Espino-Rammer, Liliana; Ribitsch, Doris; Przylucka, Agnieszka; Marold, Annemarie; Greimel, Katrin J; Herrero Acero, Enrique; Guebitz, Georg M; Kubicek, Christian P; Druzhinina, Irina S

2013-07-01

73

Directed immobilization of protein-coated nanospheres to nanometer-scale patterns fabricated by electron beam lithography of poly(ethylene glycol) self-assembled monolayers.  

PubMed

Controlling the spatial organization of biomolecules on solid supports with high resolution is important for a wide range of scientific and technological problems. Here we report a study of electron beam lithography (EBL) patterning of a self-assembled monolayer (SAM) of the amide-containing poly(ethylene glycol) (PEG) thiol CH(3)O(CH(2)CH(2)O)(17)NHCO(CH(2))(2)SH on Au and demonstrate the patterning of biomolecular features with dimensions approaching 40 nm. The electron dose dependence of feature size and pattern resolution is studied in detail by atomic force microscopy (AFM), which reveals two distinct patterning mechanisms. At low doses, the pattern formation occurs by SAM ablation in a self-developing process where the feature size is directly dose-dependent. At higher doses, electron beam-induced deposition of material, so-called contamination writing, is seen in the ablated areas of the SAM. The balance between these two mechanisms is shown to depend on the geometry of the pattern. The patterned SAMs were backfilled with fluorescent 40-nm spheres coated with NeutrAvidin. These protein-coated spheres adhered to exposed areas in the SAM with high selectivity. This direct writing approach for patterning bioactive surfaces is a fast and efficient way to produce patterns with a resolution approaching that of single proteins. PMID:16700600

Rundqvist, Jonas; Hoh, Jan H; Haviland, David B

2006-05-23

74

Facile construction of sulfanyl-terminated poly(ethylene glycol)-brushed layer on a gold surface for protein immobilization by the combined use of sulfanyl-ended telechelic and semitelechelic poly(ethylene glycol)s.  

PubMed

A sulfanyl-terminated poly(ethylene glycol) (PEG)-brushed layer was constructed on a gold sensor platform by consecutive treatment with a sulfanyl-ended semitelechelic PEG (2 kDa, hereafter "MeO-PEG-SH (2k)") and a sulfanyl-ended telechelic PEG (5 kDa, hereafter "SH-PEG-SH (5k)"). Our strategy of constructing the sulfanyl-terminated PEG-brushed gold surface is based on mixed-PEG-brush formation from the longer SH-PEG-SH (5k) and the shorter MeO-PEG-SH (2k), where the preimmobilized shorter MeO-PEG-SH (2k) prevents loop formation in the longer SH-PEG-SH (5k) on the surface and the free sulfanyl group at one end of the longer SH-PEG-SH is exposed to the mixed-PEG tethered-chain surface. From the experimental results obtained from surface plasmon resonance analysis, it became apparent that the immobilization density and the orientation of the longer SH-PEG-SH (5k) on the gold surface could be controlled by the amount of preimmobilized shorter MeO-PEG-SH (2k). Under the optimized conditions of MeO-PEG-SH (2k) premodification, the constructed MeO-PEG-SH (2k)/SH-PEG-SH (5k) mixed layer conjugated efficiently with the maleimide-installed proteins and the antibody Fab' fragments, accompanied by an appreciable nonfouling characteristic against bovine serum albumin as strong as that of the MeO-PEG-SH (5k)/MeO-PEG-SH (2k) mixed surface, which was reported in our previous work; it also showed a superior nonfouling characteristic compared to the commercially available carboxymethylated dextran surface (Uchida, K.; et al. Biointerphase 2007, 2 (4), 126-130). Furthermore, from the experimental results of the X-ray photoelectron spectrometry analysis, the presence of both Au-bound and Au-unbound sulfur species was confirmed on the SH-PEG-SH (5k)/MeO-PEG-SH (2k)-modified gold surface. These results clearly indicate that the preimmobilized shorter MeO-PEG-SH (2k) not only increased the nonfouling characteristic of the PEG tethered-chain surface but also prevented loop formation in the longer SH-PEG-SH (5k) on the gold surface. Since the protein-installed SH-PEG-SH (5k)/MeO-PEG-SH (2k)-modified surface showed a strongly nonfouling characteristic and recognized the target molecules selectively, this new mixed-brush-formation technique using longer sulfanyl-ended telechelic PEGs and shorter semitelechelic PEGs is a simple yet effective method of constructing a strongly nonfouling terminal-functionalized gold surface for protein immobilization. PMID:18666758

Yoshimoto, Keitaro; Hirase, Takumi; Nemoto, Seiko; Hatta, Tamao; Nagasaki, Yukio

2008-09-01

75

Specific Adsorption of Histidine-Tagged Proteins on Silica Surfaces Modified with Ni2+:NTA-Derivatized Poly(Ethylene Glycol)  

PubMed Central

Silica surfaces modified with nitrilotriacetic acid (NTA)-polyethylene glycol (PEG) derivatives were used for immobilizing hexahistidine-tagged green fluorescent oprotein (his6-GFP), biotin/streptavidin-AlexaFluor555 (his6-biotin/SA-AF) and gramicidin A-containing vesicles (his6-gA). Three types of surface-reactive PEG derivatives—NTA-PEG3400-Si(OMe)3, NTA-PEG3400-vinylsulfone, and mPEG5000-Si(OMe)3 (control)—were grafted onto silica and tested for their ability to capture his6-tag species via his6:Ni2+:NTA chelation. The composition and thicknesses of the PEG-modified surfaces were characterized using x-ray photoelectron spectroscopy, contact angle, and ellipsometry. Protein capture efficiencies of the NTA-PEG-grafted surfaces were evaluated by measuring fluorescence intensities of these surfaces after exposure to his6-tag species. XPS and ellipsometry data indicate that surface adsorption occurs via specific interactions between the his6-tag and the Ni2+:NTA-PEG-grafted surface. Protein immobilization was most effective for NTA-PEG3400-Si(OMe)3-modified surfaces, with maximal areal densities achieved at 45 pmol/cm2 for his6-GFP and 95 fmol/cm2 for his6-biotin/SA-AF. Lipid vesicles containing his6-gA in a 1:375 gA:lipid ratio could also be immobilized on Ni2+:NTA-PEG3400-Si(OMe)3-modified surfaces at 0.5 mM total lipid. Our results suggest that NTA-PEG-Si(OMe)3 conjugates may be useful tools for immobilizing his6-tag proteins on solid surfaces to produce protein-functionalized surfaces.

Kang, Eunah; Park, Jin-won; McClellan, Scott; Kim, Jong-Mok; Holland, David; Lee, Gil U.; Franses, Elias; Park, Kinam; Thompson, David H.

2008-01-01

76

Effect of poly(ethylene glycol), tetramethylammonium hydroxide, and other surfactants on enhancing performance in a latex particle immunoassay of C-reactive protein.  

PubMed

The influence of a variety and combination of both ionic surfactants and different chain lengths of the polyelectrolyte poly(ethylene glycol) (PEG) on the performance characteristics (with particular reference to signal response) of a homogeneous, latex agglutination immunoassay was investigated. The test analyte was human serum C-reactive protein (CRP), and the antibody reagent consisted of a sheep polyclonal anti-CRP IgG fraction covalently coupled to 50-nm-sized latex including a glycine-capped chloromethylstyrene shell. The amount and rate of immunoagglutination was monitored turbidimetrically after sample addition. It was found that 2.5 mmol/L concentrations of the small cationic surfactant tetramethylammonium hydroxide (TMH), when present alone, substantially increased both reaction rates and sensitivity in the lower clinical ranges of CRP concentration when compared to normally used assay conditions containing PEG and the anionic detergent Gafac. The nonspecific binding (NSB) was also found to be unchanged. Evidence is presented that the TMH enhances the actual antibody-antigen interaction as opposed to the known effects of other surfactants in immunocomplex dissociation or in maintenance of colloidal stability. We suggest that the enhancement seen with TMH could be an alternative to PEG and may provide a new means of further extending detection limits. The utility of this type of immunoassay technology could therefore be increased whenever clinically required. PMID:11476244

Holownia, P; Perez-Amodio, S; Price, C P

2001-07-15

77

High molecular weight polyethylene glycol cellular distribution and PEG-associated cytoplasmic vacuolation is molecular weight dependent and does not require conjugation to proteins.  

PubMed

Conjugation of therapeutic proteins with high molecular weight polyethylene glycols (HMW PEGs) is used to extend the half-life of biologics. To evaluate the effects of HMW PEGs in animals, we used an immunohistochemical procedure to study the tissue distribution and toxicity of unconjugated HMW PEGs in rats given 100 mg/kg (10K)PEG, (20K)PEG, or (40K)PEG intravenously. Both the PEG cellular distribution and the histology were different between groups. In (10K)PEG and (20K)PEG groups, PEG immunoreactivity was most prominent in the renal tubule epithelium and in alveolar macrophages and hepatic Kupffer cells and cellular vacuolation was absent. In contrast, rats given (40K)PEG had strong PEG immunoreactivity in splenic subcapsular red pulp macrophages, renal interstitial macrophages, and choroid plexus epithelial cells that was frequently associated with cytoplasmic vacuolation. While the vacuolation appeared to be an adaptive response, there was focal renal tubular epithelial degeneration associated with strong PEG immunoreactivity in one rat given (40K)PEG. These data indicate that both the tissue distribution and the vacuolation observed with unconjugated HMW PEGs are markedly influenced by the molecular weight of the PEG and that when vacuolation is observed it is likely an adaptive change that is associated with PEG cytoplasmic immunoreactivity. PMID:23788571

Rudmann, Daniel G; Alston, James T; Hanson, Jeffrey C; Heidel, Shawn

2013-01-01

78

A functionalized poly(ethylene glycol)-based bioassay surface chemistry that facilitates bio-immobilization and inhibits non-specific protein, bacterial, and mammalian cell adhesion  

PubMed Central

This paper describes a new bioassay surface chemistry that effectively inhibits non-specific biomolecular and cell binding interactions, while providing a capacity for specific immobilization of desired biomolecules. Poly(ethylene glycol) (PEG) as the primary component in nonfouling film chemistry is well-established, but the multicomponent formulation described here is unique in that it (1) is applied in a single, reproducible, solution-based coating step; (2) can be applied to diverse substrate materials without the use of special primers; and (3) is readily functionalized to provide specific attachment chemistries. Surface analysis data are presented, detailing surface roughness, polymer film thickness, and film chemistry. Protein non-specific binding assays demonstrate significant inhibition of serum, fibrinogen, and lysozyme adsorption to coated glass, indium tin oxide, and tissue culture polystyrene dishes. Inhibition of S. aureus and K. pneumoniae microbial adhesion in a microfluidic flow cell, and inhibition of fibroblast cell adhesion from serum-based cell culture is shown. Effective functionalization of the coating is demonstrated by directing fibroblast adhesion to polymer surfaces activated with an RGD peptide. Batch-to-batch reproducibility data are included. The in situ cross-linked PEG-based coating chemistry is unique in its formulation, and its surface properties are attractive for a broad range of in vitro bioassay applications.

Harbers, Gregory M.; Emoto, Kazunori; Greef, Charles; Metzger, Steven W.; Woodward, Heather N.; Mascali, James J.; Grainger, David W.; Lochhead, Michael J.

2008-01-01

79

Protocols for production of selenomethionine-labeled proteins in 2-L polyethylene terephthalate bottles using auto-induction medium  

Microsoft Academic Search

Protocols have been developed and applied in the high-throughput production of selenomethionine labeled fusion proteins using the conditional Met auxotroph Escherichia coli B834. The large-scale growth and expression uses a chemically defined auto-induction medium containing 125mgL?1 selenomethionine, salts and trace metals, other amino acids including 10mgL?1 of methionine, vitamins except vitamin B12, and glucose, glycerol, and ?-lactose. A schematic for

Hassan K. Sreenath; Craig A. Bingman; Blake W. Buchan; Kory D. Seder; Brendan T. Burns; Holalkere V. Geetha; Won Bae Jeon; Frank C. Vojtik; David J. Aceti; Ronnie O. Frederick; George N. Phillips; Brian G. Fox

2005-01-01

80

Functional study of antibodies against a fibrogenin-binding protein in Staphylococcus epidermidis adherence to polyethylene catheters.  

PubMed

Staphylococcus epidermidis is an important pathogen in foreign body-associated infections. In a previous study, we showed that a surface-located fibrinogen-binding protein, termed Fbe, from S. epidermidis mediated the bacterial adherence to fibrinogen-coated surfaces in vitro. In the present study, we demonstrate that antibodies against Fbe can block adherence of S. epidermidis to fibrinogen-coated catheters, subcutaneously implanted catheters from rats, and peripheral venous catheters from human patients. PMID:11398109

Pei, L; Flock, J I

2001-07-01

81

Exploring the Molecular Origins of Bio(in)compatibility: Adhesion Between Proteins and Individual Chains of Poly(ethylene oxide)  

NASA Astrophysics Data System (ADS)

A critical determinant of the biocompatibility of implanted blood-contacting devices is the initial noncovalent adsorption of blood plasma proteins onto the biomaterial surface. Using high-resolution force spectroscopy, we have measured the complex intermolecular interaction forces between individual end-grafted PEO chains and a probe tip covalently bound with human serum albumin, the most abundant blood plasma protein in the human body. On approach, a long-range, nonlinear repulsive force is observed. Upon retraction, however, adhesion between the HSA probe tip and PEO chain occurs, which in many cases is strong enough to allow long-range adhesion and stretching of the individual PEO chains. The known PEO strain-induced conformational transition from the helical (ttg) to the planar (ttt) conformation is clearly observed and seen to shift to lower force values. Statistical analysis of adhesion data, comparison to a variety of control experiments, and theoretical modeling enable us to interpret these experimental results in terms of electrostatic interactions, hydrogen bonding, and steric forces.

Rixman, Monica A.; Ortiz, Christine

2002-03-01

82

Poly(ethylene glycol) grafting to poly(ether imide) membranes: influence on protein adsorption and thrombocyte adhesion.  

PubMed

The chain length and end groups of linear PEG grafted on smooth surfaces is known to influence protein adsorption and thrombocyte adhesion. Here, it is explored whether established structure function relationships can be transferred to application relevant, rough surfaces. Functionalization of poly(ether imide) (PEI) membranes by grafting with monoamino PEG of different chain lengths (Mn ?=1 kDa or 10 kDa) and end groups (methoxy or hydroxyl) is proven by spectroscopy, changes of surface hydrophilicity, and surface shielding effects. The surface functionalization does lead to reduction of adsorption of BSA, but not of fibrinogen. The thrombocyte adhesion is increased compared to untreated PEI surfaces. Conclusively, rough instead of smooth polymer or gold surfaces should be investigated as relevant models. PMID:24167100

Neffe, Axel T; von Ruesten-Lange, Maik; Braune, Steffen; Luetzow, Karola; Roch, Toralf; Richau, Klaus; Jung, Friedrich; Lendlein, Andreas

2013-12-01

83

Polyethylene Glycol 3350  

MedlinePLUS

Polyethylene glycol 3350 comes as a powder to be mixed with a liquid and taken by mouth. It is usually taken once a day as needed for up to ... to produce a bowel movement.To use the powder, follow these steps: If you are using polyethylene ...

84

Polyelectrolyte nanoparticles based on water-soluble chitosan–poly( l-aspartic acid)–polyethylene glycol for controlled protein release  

Microsoft Academic Search

Water-soluble chitosan (WSC)–poly(l-aspartic acid) (PASP)–polyethylene glycol (PEG) nanoparticles (CPP nanoparticles) were prepared spontaneously under quite mild conditions by polyelectrolyte complexation. These nanoparticles were well dispersed and stable in aqueous solution, and their physicochemical properties were characterized by turbidity, FTIR spectroscopy, dynamic light scattering (DLS), transmission electron microscope (TEM), and zeta potential. PEG was chosen to modify WSC–PASP nanoparticles to make

Shujun Shu; Xinge Zhang; Dayong Teng; Zhen Wang; Chaoxing Li

2009-01-01

85

Polypropylene-polyethylene blends  

Microsoft Academic Search

Summary Die swell behaviour and morphology of melt blends of isotactic polypropylene (PP) and high density polyethylene for pure polymers and blends with 25, 50 and 75 weight % PP are described in the present study. A light interference contrast microscopy technique was used for the morphological characterization of melt blends and extrudate samples of the blends obtained with an

N. Alle; F. E. Andersen; J. Lyngaae-Jørgensen

1981-01-01

86

Methoxy-Poly(ethylene glycol) Modified Poly(L-lactide) Enhanced Cell Affinity of Human Bone Marrow Stromal Cells by the Upregulation of 1-Cadherin and Delta-2-catenin.  

PubMed

Poly(l-lactide) (PLLA), a versatile biodegradable polymer, is one of the most commonly-used materials for tissue engineering applications. To improve cell affinity for PLLA, poly(ethylene glycol) (PEG) was used to develop diblock copolymers. Human bone marrow stromal cells (hBMSCs) were cultured on MPEG-b-PLLA copolymer films to determine the effects of modification on the attachment and proliferation of hBMSC. The mRNA expression of 84 human extracellular matrix (ECM) and adhesion molecules was analyzed using RT-qPCR to understand the underlying mechanisms. It was found that MPEG-b-PLLA copolymer films significantly improved cell adhesion, extension, and proliferation. This was found to be related to the significant upregulation of two adhesion genes, CDH1 and CTNND2, which encode 1-cadherin and delta-2-catenin, respectively, two key components for the cadherin-catenin complex. In summary, MPEG-b-PLLA copolymer surfaces improved initial cell adhesion by stimulation of adhesion molecule gene expression. PMID:24834434

Mao, Xueli; Chen, Zetao; Ling, Junqi; Quan, Jingjing; Peng, Hui; Xiao, Yin

2014-01-01

87

Methoxy-Poly(ethylene glycol) Modified Poly(L-lactide) Enhanced Cell Affinity of Human Bone Marrow Stromal Cells by the Upregulation of 1-Cadherin and Delta-2-catenin  

PubMed Central

Poly(l-lactide) (PLLA), a versatile biodegradable polymer, is one of the most commonly-used materials for tissue engineering applications. To improve cell affinity for PLLA, poly(ethylene glycol) (PEG) was used to develop diblock copolymers. Human bone marrow stromal cells (hBMSCs) were cultured on MPEG-b-PLLA copolymer films to determine the effects of modification on the attachment and proliferation of hBMSC. The mRNA expression of 84 human extracellular matrix (ECM) and adhesion molecules was analyzed using RT-qPCR to understand the underlying mechanisms. It was found that MPEG-b-PLLA copolymer films significantly improved cell adhesion, extension, and proliferation. This was found to be related to the significant upregulation of two adhesion genes, CDH1 and CTNND2, which encode 1-cadherin and delta-2-catenin, respectively, two key components for the cadherin-catenin complex. In summary, MPEG-b-PLLA copolymer surfaces improved initial cell adhesion by stimulation of adhesion molecule gene expression.

Mao, Xueli; Chen, Zetao; Ling, Junqi; Quan, Jingjing; Peng, Hui; Xiao, Yin

2014-01-01

88

Achievement of high rates of in vitro synthesis of 1,4-beta-D-glucan: activation by cooperative interaction of the Acetobacter xylinum enzyme system with GTP, polyethylene glycol, and a protein factor.  

PubMed Central

Regulatory properties of a cellulose synthase (UDP-forming)(UDPglucose:1,4-beta-D-glucan 4-beta-D-glucosyltransferase, EC 2.4.1.12) have been demonstrated by using enzyme preparations derived from cells of Acetobacter xylinum. Preparation of a particulate fraction in the presence of 20% (wt/vol) polyethylene glycol-4000 (PEG-4000) yields enzyme with activity 3- to 10-fold higher than that previously reported. The enzyme prepared in this fashion also shows a further marked, specific activation by GTP. The Ka for GTP is 34 microM. Guanosine 5'-[gamma-thio]triphosphate, an analog of GTP, is even more effective than GTP (Ka for guanosine 5'-[gamma-thio]triphosphate = 17 microM). A large number of other nucleotides and nucleotide derivatives were tested with no effect. Enzyme prepared in the absence of PEG-4000 does not respond to GTP because it lacks a protein factor necessary for GTP activation. PEG-4000 promotes the interaction of the protein factor with the enzyme. The factor itself has no synthase activity nor does it stimulate activity of the enzyme in the absence of GTP. In the presence of GTP, protein factor, and PEG-4000, initial rates of enzyme activity 200 times greater than those previously reported can be achieved. Such rates exceed 40% of the in vivo rate of cellulose synthesis from glucose.

Aloni, Y; Delmer, D P; Benziman, M

1982-01-01

89

Biodiesel permeability in polyethylene  

NASA Astrophysics Data System (ADS)

This paper reports solubility, diffusivity and permeability data for soy and rapeseed methyl esters in polyethylene together with comparisons with methyl oleate and linoleate. The solubility was estimated on the order of 5% in weight at room temperature and increased up to more than 10% at 75°C. Diffusion kinetics obeys Fick's law and measured diffusion coefficient increased from 10-13 at room temperature to 5.10-11 m2 s-1 at 75°C. No significant difference was observed between all methyl esters under study. These data were used to discuss the reliability of predictive models for diffusion and solubility of additive type molecules into semi-crystalline thermoplastic polymers.

Richaud, Emmanuel; Fayolle, Bruno; Flaconnèche, Bruno; Verdu, Jacques

2012-07-01

90

Electrical conduction in polyethylene terephthalate and polyethylene films  

Microsoft Academic Search

Electrical conduction is studied in polyethylene terephthalate and to a limited extent in polyethylene over a range of fields up to 1·2×106 V cm?1. In common with previous investigations, it is found that the current decays with time according to an inverse power law, but this can be obviated by a conditioning procedure which then allows steady values of current

D M Taylor; T J Lewis

1971-01-01

91

INDUCED CONDUCTIVITIES IN IRRADIATED POLYETHYLENE  

Microsoft Academic Search

Induced conductivities in irradiated polyethylene were observed as ; functions of dose rate and applied voltage. Irradiated polyethylenes were ; prepared with electron beams from a Van de Graaff Generator. The total doses of ; radiation were from about 10⁷ rad to 10⁸ rad. The experiments on ; induced conductivities were carried out under gamma irradiation from Co⁶°. ; The

K. Yahagi; K. Shinohara; K. Mori; E. Fukada

1963-01-01

92

Solubilization of native integral membrane proteins in aqueous buffer by noncovalent chelation with monomethoxy poly(ethylene glycol) (mPEG) polymers.  

PubMed

Highly hydrophobic integral membrane proteins (IMPs)are typically purified in excess detergent media, often resulting in rapid inactivation and denaturation of the protein. One promising approach to solve this problem is to couple hydrophilic polymers, such as monomethoxypolyethylene glycol (mPEG) to IMPs under mild conditions in place of detergents. However, the broad application of this approach is hampered by poor reaction efficiencies, low tolerance of detergent stabilized membrane proteins to reaction conditions, and a lack of proper site-specific reversible approaches. Here, we have developed a straightforward, efficient, and mild approach to site-specific noncovalent binding of long-chain polymers to recombinant IMPs. This method uses the hexa-histidine tag (His-Tag) often used for purification of recombinant proteins as an attachment site for mPEGs. Solubility studies performed using five different IMPs confirmed that all tested mPEG-bound IMPs were completely soluble and stable in detergent free aqueous buffer compared to their precipitated native proteins under the identical circumstances. Activity assays and circular dichroism (CD) spectroscopy confirmed the structural integrity of modified IMPs. PMID:21740061

Janaratne, Thamara K; Okach, Linda; Brock, Ansgar; Lesley, Scott A

2011-08-17

93

Solubilization of native integral membrane proteins in aqueous buffer by non-covalent chelation with monomethoxy polyethylene glycol (mPEG) polymers  

PubMed Central

Highly hydrophobic integral membrane proteins (IMPs) are typically purified in excess detergent media, often resulting in rapid inactivation and denaturation of the protein. One promising approach to solve this problem is to couple hydrophilic polymers, such as monomethoxypolyethylene glycol (mPEG) to IMPs under mild conditions in place of detergents. However, the broad application of this approach is hampered by poor reaction efficiencies, low tolerance of detergent stabilized membrane proteins to reaction conditions and a lack of proper site-specific reversible approaches. Here we have developed a straightforward, efficient and mild approach to site-specific non-covalent binding of long-chain polymers to recombinant IMPs. This method uses the hexa-histidine tag (His-Tag) often used for purification of recombinant proteins as an attachment site for mPEGs. Solubility studies performed using five different IMPs confirmed that all tested mPEG-bound IMPs were completely soluble and stable in detergent free aqueous buffer compared to their precipitated native proteins under the identical circumstances. Activity assays and circular dichroism (CD) spectroscopy confirmed the structural integrity of modified IMPs.

Janaratne, Thamara K.; Okach, Linda; Brock, Ansgar; Lesley, Scott A.

2011-01-01

94

Polarized XANES studies of oriented polyethylene and fluorinated polyethylenes  

NASA Astrophysics Data System (ADS)

Polarization dependent XANES spectra were obtained by use of synchrotron radiation for oriented polyethylene and fluorinated polyethylenes: (1) elongated polyethylene (PE) film, (2) elongated poly(vinylidene fluoride) (PVDF) film, (3) poly(tetrafluoroethylene) (PTFE) film, (4) oriented evaporated film of hexatriacontane. CH3(CH2)34CH3 as a model compound of PE, (5) oriented evaporated film of perfluoroeicosane, CF3(CF2)18CF3 as a model compound of PTFF. Pronounced polarization dependence was observed for each compound, which allows unambiguous assignments of the XANES spectrum. Fluorination effects on the XANES spectra was also discussed

Ohta, Toshiaki; Seki, Kazuhiko; Yokoyama, Toshihiko; Morisada, Ikuo; Edamatsu, Kunishige

1990-01-01

95

A core-shell-type fluorescent nanosphere possessing reactive poly(ethylene glycol) tethered chains on the surface for zeptomole detection of protein in time-resolved fluorometric immunoassay.  

PubMed

To increase the sensitivity and to depress the nonspecific binding in biochemical assays, a new core-shell-type fluorescent nanosphere (106.7 nm) covalently conjugated with antibody was prepared. The core-shell-type nanosphere was constructed by dispersion radical polymerization of styrene in the presence of heterotelechelic poly(ethylene glycol) (PEG) macromonomer, which has a polymerizable vinylbenzyl group at one end and a primary amino group at the other chain end and used as well as a surfactant. The resulting nanosphere had PEG tethered chains on the surface, which possesses a primary amino group at the distal end of the PEG chain (NH(2) nanosphere). The fluorescent NH(2) nanosphere was constructed by incorporating fluorescent europium chelates with beta-diketonate ligands in the core of the NH(2) nanosphere by means of a physical entrapment method. The primary amino groups on the fluorescent NH(2) nanosphere were then converted to maleimide groups using a hetero cross-linker. The resulting nanosphere had maleimide groups on the surface (maleimide nanosphere), onto which proteins having SH group in the molecule could be covalently conjugated quantitatively without any denaturation of the proteins under the milder reaction condition. The applicability of the fluorescent nanosphere was tested in a model sandwich immunoassay for alpha-fetoprotein (AFP) determination. Anti-human AFP Fab' fragment was covalently conjugated onto the maleimide nanosphere (Fab' nanosphere), and it was used for the solid-phase time-resolved fluorometric immunoassay of AFP. The detection limit (mean + 2 SD) was 0.040 pg/mL or 57.1 zmol (57.1 x 10(-)(21) mol, M(w,AFP) = 70000) for AFP. The imprecision (concentration CV) over the whole assay range was 1.1% (100 pg/mL) - 17.1% (0.1 pg/mL), even though with this conjugation of antibody to the nanosphere, the nonspecific binding was practically negligible (0.0008%) and even when approximately 1.9 x 10(9) particles of the Fab' nanosphere were applied to the microtitration well. PMID:14615991

Matsuya, Takeshi; Tashiro, Shigeru; Hoshino, Nobuhiro; Shibata, Naoya; Nagasaki, Yukio; Kataoka, Kazunori

2003-11-15

96

21 CFR 177.1615 - Polyethylene, fluorinated.  

Code of Federal Regulations, 2013 CFR

...CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS...Single and Repeated Use Food Contact Surfaces § 177.1615 Polyethylene...may be safely used as food-contact articles in accordance with...Fluorinated polyethylene food-contact articles are...

2013-04-01

97

Aminolysis of polyethylene terephthalate waste  

Microsoft Academic Search

Polyethylene terephthalate in the form of waste fibres and disposable soft drink bottles was subjected to depolymerisation through aminolysis using excess of ethanolamine in the presence of different simple chemicals, namely glacial acetic acid, sodium acetate and potassium sulphate, as catalysts. The product bis(2-hydroxy ethylene)terephthalamide (BHETA) obtained was in its pure form with sufficiently high yields with all the catalysts.

S. R. Shukla; Ajay M. Harad

2006-01-01

98

Isolated Polyethylene Exchange versus Acetabular Revision for Polyethylene Wear  

PubMed Central

Polyethylene wear and osteolysis are not uncommon in THA mid- and long-term. In asymptomatic patients the dilemma faced by the orthopaedic surgeon is whether to revise the cup and risk damage to the supporting columns and even pelvic discontinuity or to perform isolated polyethylene exchange and risk a high rate of postoperative recurrent instability and dislocation that will necessitate further surgery. We retrospectively reviewed 62 patients (67 hips) who underwent revision arthroplasty for polywear and osteolysis. Thirty-six hips had isolated polyethylene exchange, while 31 had full acetabular revision. The minimum followup was 2 years (mean, 2.8 years; range, 2–5 years). Three of 36 hips with a retained cup grafted through the cup holes failed within 5 years due to acetabular loosening. One of 31 hips with full revision underwent re-revision for aseptic cup loosening at 5 months postoperatively. Although we do not recommend prophylactic revision of all cups for polywear and osteolysis, the patient may be warned of the possibility of an approximate 10% failure rate when retaining the acetabular component. We do, however, advocate cup extraction in the following situations: damage to the locking mechanism, erosion of the femoral head through the liner and into the cup damaging the metal, and a malpositioned component that may jeopardize the stability of the revision. Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Restrepo, Camilo; Ghanem, Elie; Houssock, Carrie; Austin, Mathew; Parvizi, Javad

2008-01-01

99

Complement activation on degraded polyethylene glycol-covered surface  

Microsoft Academic Search

Surface modification with polyethylene glycol (PEG) has been employed in the development of biomaterials to reduce unfavorable reactions. However, unanticipated body reactions have been reported, with activation of the complement system being suggested as having involvement in these responses. In this study, we prepared a PEG-modified surface on a gold surface using a monolayer of ?-mercaptoethyl-?-methoxy-polyoxyethylene. We observed neither protein

Mitsuaki Toda; Yusuke Arima; Hiroo Iwata

2010-01-01

100

Shock induced dissociation of polyethylene  

SciTech Connect

To identify the physical processes occurring on the Hugoniot, shock-recovery experiments were performed. Cylindrical recovery systems were used that enabled a wide range of single-shock Hugoniot states to be examined. Mass spectroscopy was used to examine the gaseous dissociation products. X-ray and TEM measurements were made to characterize the post-shock carbon structures. A dissociation product equation of state is presented to interpret the observed results. Polyethylene (PE) samples that were multiply shocked to their final states dissociated at much higher pressures than single-shocked samples. 5 refs., 2 figs., 1 tab.

Morris, C.E.; Loughran, E.D.; Mortensen, G.F.; Gray, G.T. III; Shaw, M.S.

1989-01-01

101

Thin polyethylene pressure sensitive labels  

US Patent & Trademark Office Database

The invention is directed to an ultra thin pressure sensitive adhesive construction suitable for the high speed application of label mounting equipment. The labels include a polyethylene film having a density of from 0.917 to 0.924 g/cm.sup.3 and a thickness of less than 1.8 mils; a pressure sensitive adhesive on one surface of the film; and a release composition coated paper liner having a thickness of less than 2.2 mils releasaby attached to the pressure sensitive adhesive.

2008-07-15

102

21 CFR 177.1600 - Polyethylene resins, carboxyl modified.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Polyethylene resins, carboxyl modified. 177.1600 Section...Surfaces § 177.1600 Polyethylene resins, carboxyl modified. Carboxyl-modified polyethylene resins may be safely used as the...

2011-04-01

103

21 CFR 177.1600 - Polyethylene resins, carboxyl modified.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Polyethylene resins, carboxyl modified. 177.1600 Section...Surfaces § 177.1600 Polyethylene resins, carboxyl modified. Carboxyl-modified polyethylene resins may be safely used as the...

2012-04-01

104

76 FR 54791 - Polyethylene Terephthalate (PET) Film From Korea  

Federal Register 2010, 2011, 2012, 2013

...Third Review] Polyethylene Terephthalate (PET) Film From Korea Determination On the basis...duty order on polyethylene terephthalate (PET) film from Korea would not be likely to...entitled Polyethylene Terephthalate (PET) Film from Korea: Investigation No....

2011-09-02

105

21 CFR 177.1630 - Polyethylene phthalate polymers.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Polyethylene phthalate polymers. 177.1630 Section 177.1630...Contact Surfaces § 177.1630 Polyethylene phthalate polymers. Polyethylene phthalate polymers identified in this section...

2009-04-01

106

21 CFR 177.1630 - Polyethylene phthalate polymers.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Polyethylene phthalate polymers. 177.1630 Section 177.1630...Contact Surfaces § 177.1630 Polyethylene phthalate polymers. Polyethylene phthalate polymers identified in this section...

2010-01-01

107

Vibrational analysis of polyethylene terephthalate and its deuterated derivatives  

Microsoft Academic Search

The vibrational analysis of polyethylene terephthalate, polyethylene-dâ terephthalate, and polyethylene terephthalate-dâ was carried out using a valence force field calculated from the infrared and Raman spectra of a series of low molecular weight aromatic esters. The Raman spectra for polyethylene-dâ terephthalate and polyethylene terephthalate-dâ are presented and band assignments for these compounds and polyethylene terephthalate are discussed. (auth)

F. J. Boerio; S. K. Bahl; G. E. McGraw

1976-01-01

108

Long term property prediction of polyethylene nanocomposites  

Microsoft Academic Search

The amorphous fraction of semicrystalline polymers has long been thought to be a significant contributor to creep deformation. In polyethylene (PE) nanocomposites, the semicrystalline nature of the maleated PE compatibilizer leads to a limited ability to separate the role of the PE in the nanocomposite properties. This dissertation investigates blown films of linear low-density polyethylene (LLDPE) and its nanocomposites with

Ali Al-Abed Shaito

2008-01-01

109

Polyethylene crystallization in compatibilized polyethylene/polyamide 6 blends  

NASA Astrophysics Data System (ADS)

Blends of semicrystalline polymers can exhibit much better properties than each of the pure polymers regarding e.g. impact/modulus compromise. Controlling the crystallization mechanisms (nucleation, kinetics) is a key factor to obtain the desired morphologies which lead to these unique properties. We have studied the crystallization of polyethylene (PE) in blends of PE and polyamide 6 (PA) compatibilized by PE functionalized with maleic anhydride (PE-g-MA, 1 wt% MA) obtained by reactive blending. Samples with different amounts of PA6 (0-60 %vol) have been investigated by polarized optical microscopy and Differential Scanning Calorimetry. The samples were heated at a temperature above the melting temperature of PE and below the melting temperature of PA, and then cooled at the selected crystallization temperature. We describe how the crystallization kinetics is modified by the presence of PA and MA.

Ceccia, Simona; Hynstova, Katerina; Fabre, Alexandra; Trouillet-Fonti, Lise; Long, Didier; Sotta, Paul

2011-03-01

110

Assessment of the Effects of Attaching an Enzyme to Glass by a Poly(ethylene glycol) Tether  

Microsoft Academic Search

Modification of surfaces and proteins by attaching poly(ethylene glycol) (PEG) is an important technique for controlling the properties of these materials. Our goal is to examine the possible combination of these effects by linking proteins to surfaces via a PEG spacer or tether. In the present work we have coupled alkaline phosphatase (as a model protein) to porous glass by

J. Milton Harris; Koji Yoshinaga

1989-01-01

111

Chemical modification of lipase with polyethylene glycol  

SciTech Connect

Proteins become soluble in selected organic solvents after covalent attachment of polyethylene glycol (PEG) to the free amino groups. A crude Candida rugosa lipase preparation was coupled with activated PEG to yield a PEG-lipase with both hydrolytic and synthetic activity in aqueous and organic media. The coupling step involved a modification of the procedure of Inada et al. To maintain lipase activity, mild reaction conditions were used: pH 7.5 or 8.0 buffer, 20 minutes reaction at room temperature. Up to 87% of the initial activity is retained in PEG-lipase. The PEG-lipase is soluble in aqueous solution, benzene and trichloroethane. The hydrolytic and synthetic activity of PEG-lipase in various organic solvents is compared to that of the native lipase; the PEG-lipase consistently shows higher specific activity, PEG-lipase also shows activity in iso-octane and cyclohexane, in which it is insoluble. The stability of PEG- and native lipase is solvent dependent.

Baillargeon, M.W.; Sonnet, P.E.

1986-05-01

112

Photolithographic patterning of polyethylene glycol hydrogels.  

PubMed

A simple, inexpensive photolithographic method for surface patterning deformable, solvated substrates is demonstrated using photoactive poly(ethylene glycol) (PEG)-diacrylate hydrogels as model substrates. Photolithographic masks were prepared by printing the desired patterns onto transparencies using a laser jet printer. Precursor solutions containing monoacryloyl-PEG-peptide and photoinitiator were layered onto hydrogel surfaces. The acrylated moieties in the precursor solution were then conjugated in monolayers to specific hydrogel regions by exposure to UV light through the transparency mask. The effects of UV irradiation time and precursor solution concentration on the levels of immobilized peptide were characterized, demonstrating that bound peptide concentration can be controlled by tuning these parameters. Multiple peptides can be immobilized to a single hydrogel surface in distinct patterns by sequential application of this technique, opening up its potential use in co-cultures. In addition, 3D structures can be generated by incorporating PEG-diacrylate into the precursor solution. To evaluate the feasibility of using these patterned surfaces for guiding cell behavior, human dermal fibroblast adhesion on hydrogel surfaces patterned with acryloyl-PEG-RGDS was investigated. This patterning method may find use in tissue engineering, the elucidation of fundamental structure-function relationships, and the formation of immobilized cell and protein arrays for biotechnology. PMID:16375965

Hahn, Mariah S; Taite, Lakeshia J; Moon, James J; Rowland, Maude C; Ruffino, Katie A; West, Jennifer L

2006-04-01

113

Commercialization of the polyethylene macroencapsulation process.  

National Technical Information Service (NTIS)

With support from the US Department of Energy Office of Science and Technology (DOE OST) and assistance from Brookhaven National Laboratory (BNL), Envirocare of Utah, Inc. (Envirocare) is commercializing the polyethylene macroencapsulation process. Enviro...

P. R. Lageraaen P. D. Kalb G. W. Hellstrom J. K. Vance

1998-01-01

114

21 CFR 177.1610 - Polyethylene, chlorinated.  

Code of Federal Regulations, 2013 CFR

...INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as...polyethylene consists of basic polymers produced by the direct chlorination...Reapproved 1979), âStandard Test Method for Total Chlorine in Vinyl Chloride Polymers and...

2013-04-01

115

Triboelectric Effects on Polyethylene Methane Drainage Pipelines.  

National Technical Information Service (NTIS)

The Bureau of Mines performed laboratory experiments to evaluate the triboelectric effect of particulate-laden gas streams on polyethylene pipe at various velocity, humidity, dust-size, and dust-load conditions.

A. A. Campoli J. Cervik R. L. King

1986-01-01

116

21 CFR 177.1620 - Polyethylene, oxidized.  

Code of Federal Regulations, 2013 CFR

...CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS...Single and Repeated Use Food Contact Surfaces § 177.1620 Polyethylene...used as a component of food-contact articles, in accordance with... (b) The finished food-contact article, when...

2013-04-01

117

Reusable, polyethylene glycol-structured microfluidic channel for particle immunoassays  

PubMed Central

A microfluidic channel made entirely out of polyethylene glycol (PEG), not PEG coating to silicon or polydimethylsiloxane (PDMS) surface, was fabricated and tested for its reusability in particle immunoassays and passive protein fouling, at relatively high target concentrations (1 mg ml-1). The PEG devices were reusable up to ten times while the oxygen-plasma-treated polydimethyl siloxane (PDMS) device could be reused up to four times and plain PDMS were not reusable. Liquid was delivered spontaneously via capillary action and complicated bonding procedure was not necessary. The contact angle analysis revealed that the water contact angle on microchannel surface should be lower than ~60°, which are comparable to those on dried protein films, to be reusable for particle immunoassays and passive protein fouling.

Han, Jin-Hee; Yoon, Jeong-Yeol

2009-01-01

118

Surface modification of polymeric biomaterials with poly(ethylene oxide), albumin, and heparin for reduced thrombogenicity  

Microsoft Academic Search

Appropriate surface modification has significantly improved the blood compatibility of polymeric biomaterials. This article reviews methods of surface modification with water-soluble polymers, such as polyethylene oxide (PEO), albumin, and heparin. PEO is a synthetic, neutral, watersoluble polymer, while albumin and heparin are a natural globular protein and an anionic polysaccharide, respectively. When grafted onto the surface, all three macromolecules share

Mansoor Amiji

1993-01-01

119

Adsorption of peptides and small proteins with control access polymer permeation to affinity binding sites. Part I: Polymer permeation-immobilized metal ion affinity chromatography separation adsorbents with polyethylene glycol and immobilized metal ions  

Microsoft Academic Search

Despite the many efforts to develop efficient protein purification techniques, the isolation of peptides and small proteins on a larger than analytical scale remains a significant challenge. Recovery of small biomolecules from diluted complex biological mixtures, such as human serum, employing porous adsorbents is a difficult task mainly due to the presence of concentrated large biomolecules that can add undesired

Jerker Porath

2012-01-01

120

Protein  

NSDL National Science Digital Library

Protein structure: Primary protein structure is a sequence of amino acids. Secondary protein structure occurs when the amino acids in the sequence are linked by hydrogen bonds. Tertiary protein structure occurs when certain attractions are present between alpha helices and pleated sheets. Quaternary protein structure is a protein consisting of more than one amino acid chain.

BEGIN:VCARD VERSION:2.1 FN:Darryl Leja N:Leja;Darryl ORG:National Human Genome Research Institute REV:2005-04-04 END:VCARD

2005-04-04

121

Degradation studies of novel degradable starch-polyethylene plastics containing oxidized polyethylene and prooxidant  

Microsoft Academic Search

Linear low-density polyethylene films were prepared that contained native corn starch (7, 14, or 28%), low or high molecular weight oxidized polyethylene (15%), and a prooxidant mixture (18% POLYCLEAN II) that contains manganese and vegetable oil. For each mixture all components were first mixed at high temperatures in a twin-screw extruder and pelletized. The pellets were cast into films using

Meera Kim; Anthony L. Pometto; Kenneth E. Johnson; Alfred R. Fratzke

1994-01-01

122

Polarized absorption spectra of polyethylene terephthalate and polyethylene naphthalate films in soft x-ray region  

Microsoft Academic Search

Using polarized nature of synchrotron radiation, core electron absorption spectra of thin films of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) were investigated. Aromatic rings in these films tend to lie in the film plane when the films are drawn uniaxially or, in particular, biaxially; previous interpretation of their core electron spectra based on their nature above was reinforced by

Isuke Ouchi; Ikuo Nakai; Masao Kamada; Shin-ichiro Tanaka

1996-01-01

123

Study on thermal diffusivity of poly(ethylene terephthalate) and poly(ethylene naphthalate)  

Microsoft Academic Search

Thermal diffusivity (?) of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) was measured by an AC joule heating technique as a function of temperature from the solid to the liquid state; ? changed drastically at the glass transition and at crystallization. In a heating run on the quenched sample, an abrupt increase of a immediately after the glass transition was

Junko Morikawa; Toshimasa Hashimoto

1997-01-01

124

Behaviour in soil of polyethylene film and polyethylene film additivated with starch  

Microsoft Academic Search

The ever increasing use of plastic films for the manufacture of commonly used objects, and, therefore, their increasing presence in municipal solid waste, has, in recent years, made biodegradability a useful characteristic for these products. This study investigates films designated biodegradable and examines their actual capacity to biodegrade on burial in soil. The films tested were polyethylene and polyethylene with

L. Volterra; L. Musmeci; P. M. B. Gucci; A. M. Coccia; S. Esposito

1996-01-01

125

21 CFR 870.3470 - Intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or...  

Code of Federal Regulations, 2010 CFR

...made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...made of polypropylene, polyethylene terephthalate, or...

2010-04-01

126

21 CFR 870.3470 - Intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or...  

Code of Federal Regulations, 2010 CFR

...made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...made of polypropylene, polyethylene terephthalate, or...

2009-04-01

127

76 FR 8770 - Polyethylene Terephthalate (Pet) Film From Korea  

Federal Register 2010, 2011, 2012, 2013

...COMMISSION [Investigation No. 731-TA-459 (Third Review)] Polyethylene Terephthalate (Pet) Film From Korea AGENCY: United States...five-year review concerning the antidumping duty order on polyethylene terephthalate (PET) film from...

2011-02-15

128

Alumina-on-Polyethylene Bearing Surfaces in Total Hip Arthroplasty  

PubMed Central

The long-term durability of polyethylene lining total hip arthroplasty (THA) mainly depends on periprosthetic osteolysis due to wear particles, especially in young active patients. In hip simulator study, reports revealed significant wear reduction of the alumina ceramic-on-polyethylene articulation of THA compared with metal-on-polyethylene bearing surfaces. However, medium to long-term clinical studies of THA using the alumina ceramic-on-polyethylene are few and the reported wear rate of this articulation is variable. We reviewed the advantages and disadvantages of ceramicon- polyethylene articulation in THA, hip simulator study and retrieval study for polyethylene wear, in vivo clinical results of THA using alumina ceramic-on-polyethylene bearing surfaces in the literature, and new trial alumina ceramic-onhighly cross linked polyethylene bearing surfaces.

Jung, Yup Lee; Kim, Shin-Yoon

2010-01-01

129

21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.  

Code of Federal Regulations, 2013 CFR

...Production Aids § 178.3760 Polyethylene glycol (400) monolaurate. Polyethylene glycol (400) monolaurate containing not more than 0.1 percent by weight of ethylene and/or diethylene glycol may be used at a level not to...

2013-04-01

130

Feasibility Study of The Disposal of Polyethylene Plastic Waste.  

National Technical Information Service (NTIS)

Synthetic plastics as polyethylene do not decompose when disposed of in landfills and can cause air pollution problems if burned. An efficient, safe, and economical method for the disposal of wastes as polyethylene is needed. A feasibility study directed ...

K. Gutfreund

1971-01-01

131

Interaction of polyethylene glycol-6000 with C 4 phosphoenolpyruvate carboxylase in crude leaf extracts as well as in purified protein form from Amaranthus hypochondriacus L.: evidence for oligomerization of PEPC in vitro and in vivo  

Microsoft Academic Search

The interaction of phosphoenolpyruvate carboxylase (PEPC) with a compatible solute, PEG-6000, was examined using crude leaf\\u000a extracts as well as the purified protein from leaves of Amaranthus hypochondriacus, a NAD-malic enzyme type C4 plant. The inclusion in the assay medium of PEG-6000 stimulated the activity of purified PEPC by about 2.5-fold over control.\\u000a The addition of PEG during both extraction

G. Swaminath; Uday K. Avasthi; Agepati S. Raghavendra

2008-01-01

132

Preparation and characterization of polyethylene\\/Kevlar composite foams  

Microsoft Academic Search

In this study, polyethylene\\/KevlarRTM composite foams were investigated in order to determine the relation between the morphology and mechanical properties of composite foams. To do so, it was necessary to explore the morphology and mechanical properties of these materials. First, high density polyethylene foams were investigated. The effects of molecular mass of polyethylene and blowing agent concentration on the foaming

Yaolin Zhang

2003-01-01

133

Halogen-free flame retardation and silane crosslinking of polyethylenes  

Microsoft Academic Search

Halogen-free flame-retarded and silane crosslinkable polyethylenes have been prepared by a melt process using magnesium hydroxide (MH) as a flame retardant. The effects of silane concentration, peroxide concentration, etc. on the silane grafting on linear low density polyethylenes were investigated. The thermal analysis of the silane crosslinked polyethylenes was performed by thermogravimetry (TG), and its results show that silane crosslinking

Zhengzhou Wang; Yuan Hu; Zhou Gui; Ruowen Zong

2003-01-01

134

Synthesis and characterization of maleated polyethylene\\/clay nanocomposites  

Microsoft Academic Search

Maleic anhydride grafted polyethylene (maleated polyethylene)\\/clay nanocomposites were prepared by simple melt compounding. The exfoliation and intercalation behaviors depended on the hydrophilicity of polyethylene grafted with maleic anhydride and the chain length of organic modifier in the clay. When the number of methylene groups in alkylamine (organic modifier) was larger than 16, the exfoliated nanocomposite was obtained, and the maleic

Ki Hyun Wang; Min Ho Choi; Chong Min Koo; Yeong Suk Choi; In Jae Chung

2001-01-01

135

Preservation of Mercury in Polyethylene Containers.  

ERIC Educational Resources Information Center

Reports results of experiments favoring use of 0.5 percent nitric acid with an oxidant (potassium dichromate or potassium permanganate) to preserve samples in polyethylene containers for mercury analysis. Includes procedures used and statistical data obtained from the experiments. (JN)

Piccolino, Samuel Paul

1983-01-01

136

Commercialization of the polyethylene macroencapsulation process  

Microsoft Academic Search

With support from the US Department of Energy Office of Science and Technology (DOE OST) and assistance from Brookhaven National Laboratory (BNL), Envirocare of Utah, Inc. (Envirocare) is commercializing the polyethylene macroencapsulation process. Envirocare, currently the only commercially licensed mixed waste disposal facility in the US, will initially demonstrate the process by treating and disposing up to 227,000 kg (500,000

P. R. Lageraaen; P. D. Kalb; G. W. Hellstrom; J. K. Vance

1998-01-01

137

Thermally sprayable polyethylene coatings for marine environment  

Microsoft Academic Search

Application of organic coatings is one of the methods for protection of mild steel against corrosion. In the present work, low-density polyethylene (LDPE) has been used as binder for development of anticorrosive coating. Since non-polar characteristics of LDPE make its adhesion poor to most substrates, polar groups have been introduced in LDPE by grafting maleic acid (MAc) using reactive extrusion

S. K. Singh; S. P. Tambe; V. S. Raja; Dhirendra Kumar

2007-01-01

138

Computational method for analysis of polyethylene biodegradation  

NASA Astrophysics Data System (ADS)

In a previous study concerning the biodegradation of polyethylene, we proposed a mathematical model based on two primary factors: the direct consumption or absorption of small molecules and the successive weight loss of large molecules due to ?-oxidation. Our model is an initial value problem consisting of a differential equation whose independent variable is time. Its unknown variable represents the total weight of all the polyethylene molecules that belong to a molecular-weight class specified by a parameter. In this paper, we describe a numerical technique to introduce experimental results into analysis of our model. We first establish its mathematical foundation in order to guarantee its validity, by showing that the initial value problem associated with the differential equation has a unique solution. Our computational technique is based on a linear system of differential equations derived from the original problem. We introduce some numerical results to illustrate our technique as a practical application of the linear approximation. In particular, we show how to solve the inverse problem to determine the consumption rate and the ?-oxidation rate numerically, and illustrate our numerical technique by analyzing the GPC patterns of polyethylene wax obtained before and after 5 weeks cultivation of a fungus, Aspergillus sp. AK-3. A numerical simulation based on these degradation rates confirms that the primary factors of the polyethylene biodegradation posed in modeling are indeed appropriate.

Watanabe, Masaji; Kawai, Fusako; Shibata, Masaru; Yokoyama, Shigeo; Sudate, Yasuhiro

2003-12-01

139

Preliminary investigation of a polyethylene glycol hydrogel \\  

Microsoft Academic Search

BACKGROUND: Polyethylene glycol (PEG) hydrogel is a biocompatible semi-adherent gel like substance that can potentially augment nerve repair much like a fibrin sealant. Potential advantages of this substance include fast preparation and set up time, as well as adhesion inhibiting properties. The purpose of this study was to perform an initial evaluation of PEG hydrogel in this application. METHODS: The

Jonathan Isaacs; Ivette Klumb; Candice McDaniel

2009-01-01

140

Polyethylene terephthalate (PETP) foams as ferroelectrets  

Microsoft Academic Search

Voided space-charge electrets represent a new class of piezoelectric materials, the so-called ferroelectrets. Several polymers are under investigation with respect to possible ferroelectret properties. However, processing limitations, difficulties in preparing suitably voided polymer films or unfavorable property combinations often prevent the successful generation of new ferroelectrets. Here, we describe the preparation of voided polyethylene terephthalate (PETP) ferroelectret films by means

M. Wegener; W. Wirges; J. P. Dietrich; R. Gerhard-Multhaupt

2005-01-01

141

The hot compaction of polyethylene terephthalate  

Microsoft Academic Search

A process is described for the successful compaction of polyethylene terephthalate fibres. The measurement of mechanical properties shows that a very high proportion of the original fibre properties are retained and that the compacted samples have a good degree of coherence. Electron microscopy studies of suitably etched samples reveals the effect of the compaction temperature on the structure of the

J. Rasburn; P. J. Hine; I. M. Ward; R. H. Olley; D. C. Bassett; M. A. Kabeel

1995-01-01

142

The yield behaviour of oriented polyethylene terephthalate  

Microsoft Academic Search

Oriented sheets of polyethylene terephthalate have been deformed in tension and simple shear, with the primary variable as the angle between the tensile stress or the shear stress and the initial draw direction. In tension, deformation bands were observed in all cases, as has been reported previously (Brown and Ward 1968 a), and a clear yiold point was observed in

N. Brown; R. A. Duckett; I. M. Ward

1968-01-01

143

Depolymerization of polyethylene terephthalate in supercritical methanol  

Microsoft Academic Search

The degradation of polyethylene terephthalate (PET) in supercritical methanol was investigated with the aim of developing a process for chemical recycling of waste plastics. A batch reactor was used at temperatures of 573-623 K under an estimated pressure of 20 MPa for a reaction time of 2-120 min. PET was decomposed to its monomers, dimethyl terephthalate and ethylene glycol, by

Motonobu Goto; Hiroshi Koyamoto; Akio Kodama; Tsutomu Hirose; Shoji Nagaoka

2002-01-01

144

Dynamic Mechanical Properties of Polyethylene Oxide.  

National Technical Information Service (NTIS)

Measurements were made on polyethylene oxide using a torsional braid analyzer at 0.1 Hz from room temperature to above the melting point. The relative rigidity is in general agreement with literature values of the shear modulus measured with a torsional p...

B. Hartmann

1972-01-01

145

Impact behaviour of polypropylene\\/polyethylene blends  

Microsoft Academic Search

Due to the large volume consumption of polyolefins, the treatment of the resulting solid waste is becoming a major concern. One possible utilization of the polyolefin wastes is to form blends from recycled polypropylene (PP) and polyethylene (PE). This study is a preliminary investigation on the impact fracture behaviour for the PP\\/PE blends. The impact testing method employed in this

C. M Tai; Robert K. Y Li; C. N Ng

2000-01-01

146

The Failure Rate Of Polyethylene Insulated Cable  

Microsoft Academic Search

The failure rate of polyethylene cable in utility underground distribution systems is a matter of concern throughout the industry. A major failure mechanism is electrochemical treeing which results in insulation breakdown. Electrochemical treeing in po3yethylene cable is known to be a function of voltage stress, moisture, insulation d efects and time in service. This paper deals with the formulation of

W. F. Horton; A. N. St.-John

1979-01-01

147

High-pressure vibrational properties of polyethylene  

NASA Astrophysics Data System (ADS)

The pressure evolution of the vibrational spectrum of polyethylene was investigated up to 50 GPa along different isotherms by Fourier-transform infrared and Raman spectroscopy and at 0 K by density-functional theory calculations. The infrared data allow for the detection of the orthorhombic Pnam to monoclinic P21/m phase transition which is characterized by a strong hysteresis both on compression and decompression experiments. However, an upper and lower boundary for the transition pressure are identified. An even more pronounced hysteresis is observed for the higher-pressure transition to the monoclinic A2/m phase. The hysteresis does not allow in this case the determination of a well defined P-T transition line. The ambient structural properties of polyethylene are fully recovered after compression/decompression cycles indicating that the polymer is structurally and chemically stable up to 50 GPa. A phase diagram of polyethylene up to 50 GPa and 650 K is proposed. Analysis of the pressure evolution of the Davydov splittings and of the anomalous intensification with pressure of the IR active wagging mode provides insight about the nature of the intermolecular interactions in crystalline polyethylene.

Fontana, Luca; Santoro, Mario; Bini, Roberto; Vinh, Diep Q.; Scandolo, Sandro

2010-11-01

148

Ultrasonically enhanced persulfate oxidation of polyethylene surfaces  

Microsoft Academic Search

The ultrasonically enhanced oxidation of polyethylene surfaces by potassium and ammonium persulfates is described. The use of ultrasound allows significant levels of surface modification to be achieved using these oxidizing agents under mild conditions. Changes in the water contact angle and attenuated total reflection infra-red spectra were used to follow the changes in surface chemistry. Variation of conditions such as

Fiona Keen

1996-01-01

149

Propeller Cavitation in Solutions of Polyethylene Oxide.  

National Technical Information Service (NTIS)

The inception and formation rates of bubble cavitation on a 14.8-cm diameter, two-bladed propeller were measured in homogeneous aqueous solutions of polyethylene oxide. If the results can be extended to full size propellers, ships can increase their prope...

R. J. White

1971-01-01

150

Structure and properties of compatibilized recycled poly(ethylene terephthalate)\\/linear low density polyethylene blends  

Microsoft Academic Search

Blends of recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) were compatibilized with poly(styrene-ethylene\\/butyldiene-styrene) (SEBS) and maleic anhydride-grafted poly(styrene-ethylene\\/butyldiene-styrene) (SEBS-g-MA). Effects of compatilizer were evaluated systematically by study of mechanical, thermal and morphology properties together with crystallization behavior of PET. Tensile properties of the blends were improved effectively by the addition of 10wt% SEBS-g-MA, elongation at break and

Hongsheng Zhang; Weihong Guo; Yingbo Yu; Binyao Li; Chifei Wu

2007-01-01

151

Structural development and mechanical properties of polyethylene naphthalate\\/polyethylene terephthalate blends during uniaxial drawing  

Microsoft Academic Search

The blends of poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) were obtained by melt blending at 310°C for 2min and quenching into an ice water. Mechanical properties and structural formation of unoriented amorphous PEN\\/PET blend films during drawing at 85, 100 and 130°C were studied by tensile tests and in situ X-ray measurements. The results obtained were compared with the

Elinor L Bedia; Syozo Murakami; Taku Kitade; Shinzo Kohjiya

2001-01-01

152

Type of motion and lubricant in wear simulation of polyethylene acetabular cup.  

PubMed

The wear of ultra-high molecular weight polyethylene, the most commonly used bearing material in prosthetic joints, is often substantial, posing a significant clinical problem. For a long time, there has been a need for simple but still realistic wear test devices for prosthetic joint materials. The wear factors produced by earlier reciprocating and unidirectionally rotating wear test devices for polyethylene are typically two orders of magnitude too low, both in water and in serum lubrication. Wear is negligible even under multidirectional motion in water. A twelve-station, circularly translating pin-on-disc (CTPOD) device and a modification of the established biaxial rocking motion hip joint simulator were built. With these simple and inexpensive devices, and with the established three-axis hip joint simulator, realistic wear simulation was achieved. This was due to serum lubrication and to the fact that the direction of sliding constantly changed relative to the polyethylene specimen. The type and magnitude of load was found to be less important. The CTPOD tests showed that the subsurface brittle region, which results from gamma irradiation sterilization of polyethylene in air, has poor wear resistance. Phospholipid and soy protein lubrication resulted in unrealistic wear. The introduction of devices like CTPOD may boost wear studies, rendering them feasible without heavy investment. PMID:10466361

Saikko, V; Ahlroos, T

1999-01-01

153

Sulphuric acid etching of polyethylene surfaces  

Microsoft Academic Search

The sulphuric acid etching of polyethylene results in the formation of sulphonic groups, varying the surface properties. The\\u000a study of the groups formed during the etching has been carried out by means of frustrated multiple internal reflection infrared\\u000a spectroscopy (FMIR). Densities, thermal properties, superficial resistances and resistivities have been correlated with the\\u000a content of sulphonic groups and treatment time. Moreover,

C. Fonseca; J. M. Pereña; J. G. Fatou; A. Bello

1985-01-01

154

Hydrogasification of coal and polyethylene mixture  

Microsoft Academic Search

The hydrogasification of coal and polyethylene (PE) mixtures was carried out at 1073K under 7.1MPa of hydrogen. The product distribution and temperature profile were analyzed. The yield of methane reached 90% (carbon basis) after 80s when PE was used alone. A significant synergistic effect was found when coal and PE were mixed and used in hydrogasification. This synergistic effect may

Hajime Yasuda; Osamu Yamada; Aihua Zhang; Kaoru Nakano; Mamoru Kaiho

2004-01-01

155

Overnight efficacy of polyethylene glycol laxative  

Microsoft Academic Search

OBJECTIVES:Clinical studies in constipated adult patients have shown that a 17- or 34-g daily dose of polyethylene glycol (PEG) 3350 (MiraLax) is safe and effective for the treatment of constipation, with the best efficacy seen in wk 2 of treatment. The purpose of this study was to determine an optimal dose of PEG to provide satisfactory relief of constipation within

Jack A Di Palma; Julie R Smith; Mark vB Cleveland

2002-01-01

156

The cold drawing of polyethylene terephthalate  

Microsoft Academic Search

The cold-drawing behaviour of polyethylene terephthalate has been studied over a wide range of test conditions and polymer constitution. In addition to measurements at different temperatures and strain rates, the influence of pre-orientation, crystallinity and chemical cross-linking was investigated. Although crystallinity and cross-linking altered to some extent the details of the drawing process, the overall pattern of behaviour remained substantially

S W Allison; I M Ward

1967-01-01

157

Study of friction welding of polyethylene pipes  

Microsoft Academic Search

This paper describes an investigation of the effects of the friction welding conditions on the joining phenomena and tensile strength of welded joints produced from polyethylene gas supply pipes in tests conducted on a metal brake-type friction welding machine. The results obtained may be summarised as follows:1. The friction pressure strongly affects the initial torque and total loss (burn-off) in

M. Hasegawa; T. Asada; Y. Ozawa; N. Taki

1998-01-01

158

Acetaldehyde residue in polyethylene terephthalate (PET) bottles  

Microsoft Academic Search

A simple sample preparation technique was developed for rapid analysis of acetaldehyde residue in Polyethylene Terephthalate (PET) bottles. A laboratory-built heating system was used and coupled with gas chromatography-flame ionization detector (GC-FID) at optimized conditions. The results were a tremendous reduction of the sample preparation time from 24 hours, for the conventional method, to only one hour. The analysis took

Aree Choodum; Panote Thavarungkul; Proespichaya Kanatharana

2007-01-01

159

Melt blends of polyethylene with a phenoxy  

Microsoft Academic Search

Melt blends of high density polyethylene (PE) with a phenoxy have been prepared over a full composition range using a Brabender Plasticorder. Scanning electron microscopy (SEM) micrographs showed a clear phase separation, viz. particle-in-matrix or co-continuous morphology depending on the composition. Tm (crystalline melting temperature) of PE decreased by 3–6 °C, whereas Tg (glass transition temperature) of phenoxy increased up

Chi Hoon Choi; Byung Kyu Kim

1995-01-01

160

Polyethylene compounds with antimicrobial surface properties  

Microsoft Academic Search

The present study aims at antimicrobial polyethylene surfaces. To achieve this, LLDPE was compounded with the polymeric biocide poly(2-tert-butylaminoethyl) methacrylate TBAM (bulk modification with 1.5–5.0wt.% of TBAM). Surfaces of these polymer compounds were then subjected to microbial assays. Using standard methods the colony forming units (CFU) for Escherichia coli and Staphylococcus aureus were determined on these surfaces. In all cases,

Gerhard Seyfriedsberger; Karl Rametsteiner; Wolfgang Kern

2006-01-01

161

Comparative wear tests of ultra-high molecular weight polyethylene and cross-linked polyethylene.  

PubMed

Wear particle-induced osteolysis is a major concern in hip implant failure. Therefore, recent research work has focussed on wear-resistant materials, one of the most important of which is cross-linked polyethylene. In view of this, the objective of this study was to compare the in vitro wear performance of cross-linked polyethylene to traditional ultra-high molecular weight polyethylene. In order to mimic appropriate in vivo conditions, a novel high-capacity wear tester called a circularly translating pin-on-disc was used. The results of this in vitro study demonstrated that the wear rate for cross-linked polyethylene was about 80% lower than that of conventional ultra-high molecular weight polyethylene. This difference closely matches in vivo results reported in the literature for total hip replacements that use the two biopolymers. The in vitro results were also verified against ASTM F732-00 (standard test method for wear testing of polymeric materials for use in total joint prostheses). The 50-station circularly translating pin-on-disc proved to be a reliable device for in vitro wear studies of orthopaedic biopolymers. PMID:23637270

Harsha, A P; Joyce, Tom J

2013-05-01

162

Plasma surface modification of polystyrene and polyethylene  

NASA Astrophysics Data System (ADS)

Polystyrene (PS) and polyethylene (PE) samples were treated with argon and oxygen plasmas. Microwave electron cyclotron resonance (ECR) was used to generate the argon and oxygen plasmas and these plasmas were used to modify the surface of the polymers. The samples were processed at different microwave powers and treatment time and the surface modification of the polymer was evaluated by measuring the water contact angle of the samples before and after the modification. Decrease in the contact angle was observed with the increase in the microwave power for both polystyrene and polyethylene. Plasma parameters were assessed using Langmuir probe measurements. Fourier transform infrared spectroscopy showed the evidence for the induction of oxygen-based functional groups in both polyethylene and polystyrene when treated with the oxygen plasma. Argon treatment of the polymers showed improvement in the wettability which is attributed to the process called as CASING, on the other hand the oxygen plasma treatment of the polymers showed surface functionalization. Correlation between the plasma parameters and the surface modification of the polymer is also discussed.

Guruvenket, S.; Rao, G. Mohan; Komath, Manoj; Raichur, Ashok M.

2004-09-01

163

Preparation of extruded polyethylene/chitosan blends compatibilized with polyethylene-graft-maleic anhydride.  

PubMed

Novel films of polyethylene and chitosan were obtained using extrusion. These polymers have interesting properties, and processing them with methods that are of high use in the industry, such as the extrusion method, can have a significant effect on the potential applications of these materials. The individual materials were thermally characterized; after this, extruded films of low density polyethylene and chitosan mixtures were prepared with the addition of polyethylene-graft-maleic anhydride as a compatibilizer for the blends, and glycerol, as a plasticizer for chitosan. The use of compatibilizer and plasticizer agents improved the processability and compatibility of the mixtures, as well as their mechanical properties, as revealed by mechanical property measurements and scanning electron microscopy. It was possible to prepare blends with a maximum chitosan content of 20 wt%. The material stiffness increased with the increase of chitosan in the sample. FTIR studies revealed the existence of an interaction between the compatibilizer and chitosan. PMID:24299879

Quiroz-Castillo, J M; Rodríguez-Félix, D E; Grijalva-Monteverde, H; Del Castillo-Castro, T; Plascencia-Jatomea, M; Rodríguez-Félix, F; Herrera-Franco, P J

2014-01-30

164

Proteins.  

ERIC Educational Resources Information Center

Examines proteins which give rise to structure and, by virtue of selective binding to other molecules, make genes. Binding sites, amino acids, protein evolution, and molecular paleontology are discussed. Work with encoding segments of deoxyribonucleic acid (exons) and noncoding stretches (introns) provides new information for hypotheses. (DH)

Doolittle, Russell F.

1985-01-01

165

Proteins  

NSDL National Science Digital Library

Paul Anderson explains the structure and importance of proteins. He describes how proteins are created from amino acids connected by dehydration synthesis. He shows the importance of chemical properties in the R-groups of individual amino acids in the polypeptide.

Anderson, Paul

2013-03-12

166

Fabrication and Anti-Fouling Properties of Photochemically and Thermally Immobilized Poly(Ethylene Oxide) and Low Molecular Weight Poly(Ethylene Glycol) Thin Films  

PubMed Central

Poly(ethylene oxide) (PEO) and low molecular weight poly(ethylene glycol) (PEG) were covalently immobilized on silicon wafers and gold films by way of the CH insertion reaction of perfluorophenyl azides (PFPAs) by either photolysis or thermolysis. The immobilization does not require chemical derivatization of PEO or PEG, and polymers of different molecular weights were successfully attached to the substrate to give uniform films. Microarrays were also generated by printing polymer solutions on PFPA-functionalized wafer or Au slides followed by light activation. For low molecular weight PEG, the immobilization was highly dependent on the quality of the film deposited on the substrate. While the spin-coated and printed PEG showed poor immobilization efficiency, thermal treatment of the PEG melt on PFPA-functionalized surfaces resulted in excellent film quality, giving, for example, a grafting density of 9.2 × 10?4/Å2 and an average distance between grafted chains of 33 Å for PEG 20,000. The anti-fouling property of the films was evaluated by fluorescence microscopy and surface plasmon resonance imaging (SPRi). Low protein adsorption was observed on thermally-immobilized PEG whereas the photoimmobilized PEG showed increased protein adsorption. In addition, protein arrays were created using polystyrene (PS) and PEG based on the differential protein adsorption of the two polymers.

Wang, Hui; Ren, Jin; Hlaing, Aye; Yan, Mingdi

2010-01-01

167

Polyethylene waste form: Evaluation of explosion and fire hazards  

Microsoft Academic Search

A Proposed polyethylene waste form consists of a hot-extruded, non-porous mix of equal weights of polyethylene and granular sodium nitrate, slightly contaminated with heavy metal salts. The experiments and theoretical analysis detailed in this report were done to evaluate the risks for self-accelerating thermal decomposition, explosion, and detonation of polyethylene mixed with sodium nitrate. The study included the proposed waste

A. Block-Bolten; D. Olson; P. A. Persson; F. Sandstrom

1991-01-01

168

Fiber Optic Strain Gage Verification and Polyethylene Hip Liner Testing  

Microsoft Academic Search

\\u000a To optimize stability in total hip arthroplasty, the use of larger femoral heads necessitates a polyethylene liner of reduced\\u000a thickness. An understanding of the mechanical properties, particularly resistance to fatigue failure, of highly-crosslinked\\u000a polyethylene is critical to determine the optimal parameters for clinical use. The primary purposes of this study were to\\u000a characterize the X3TM highly cross-linked polyethylene (HCLPE) liner

Lucas Chavez; Michael Martin; Stephen O. Neidigk; Phillip Cornwell; R. Michael Meneghini; Joe Racanelli

169

Effect of Elongation on Dielectric Breakdown Strength in Polyethylene  

Microsoft Academic Search

A measurement of the dielectric breakdown strength in low- and high-density polyethylene was carried out under the condition of elongation by tensile stress. The wave forms of applied voltages were a.c., d.c. and impulse (1× 40 mus) voltages, and the thickness of films of polyethylene was ca. 50 mum. In the case of low-density polyethylene, the breakdown strength with a.c.,

Saburo Mita; Kichinosuke Yahagi

1975-01-01

170

Polypropylene-Polyethylene Melts: Phase Structure Determination by Rheology  

Microsoft Academic Search

Using dynamic moduli and transmission electron microscopy images the phase structure of polypropylene-polyethylene melts was studied. Blends consisting of 80% base material (polypropylene-homopolymer or ethylene-propylene copolymer) and of 20% modifier polymer (a C2\\/C8-elastomer, a linear low density polyethylene or a high density polyethylene) forming a two-phase structure in the melt were investigated. The influence of the viscosity ratio and the

Cornelia Kock; A. Schausberger; N. Aust; M. Gahleitner; E. Ingolic

2008-01-01

171

Protein  

MedlinePLUS

... Reference, Release 14 . 2005. 4. Bernstein, A.M., et al., Major dietary protein sources and risk of ... 52 (11): p. 2277-87. 6. Pan, A., et al., Red meat consumption and mortality: results from ...

172

Protein  

MedlinePLUS

... for Everyone Introduction Nutrition Basics Food Groups Water Dietary Fat Trans Fat Saturated Fat Cholesterol Polyunsaturated Fats and Monounsaturated Fats Carbohydrates Protein Vitamins and Minerals Fruits and Vegetables Nutrition Information How Many Fruits ...

173

Mechanisms for Covalent Immobilization of Horseradish Peroxidase on Ion-Beam-Treated Polyethylene  

PubMed Central

The surface of polyethylene was modified by plasma immersion ion implantation. Structure changes including carbonization and oxidation were observed. High surface energy of the modified polyethylene was attributed to the presence of free radicals on the surface. The surface energy decay with storage time after treatment was explained by a decay of the free radical concentration while the concentration of oxygen-containing groups increased with storage time. Horseradish peroxidase was covalently attached onto the modified surface by the reaction with free radicals. Appropriate blocking agents can block this reaction. All aminoacid residues can take part in the covalent attachment process, providing a universal mechanism of attachment for all proteins. The native conformation of attached protein is retained due to hydrophilic interactions in the interface region. The enzymatic activity of covalently attached protein remained high. The long-term activity of the modified layer to attach protein is explained by stabilisation of unpaired electrons in sp2 carbon structures. A high concentration of free radicals can give multiple covalent bonds to the protein molecule and destroy the native conformation and with it the catalytic activity. The universal mechanism of protein attachment to free radicals could be extended to various methods of radiation damage of polymers.

Kondyurin, Alexey V.; Naseri, Pourandokht; Tilley, Jennifer M. R.; Nosworthy, Neil J.; Bilek, Marcela M. M.; McKenzie, David R.

2012-01-01

174

Patterned functional carbon fibers from polyethylene  

SciTech Connect

Patterned, continuous carbon fibers with controlled surface geometry were produced from a novel melt-processible carbon precursor. This portends the use of a unique technique to produce such technologically innovative fibers in large volume for important applications. The novelties of this technique include ease of designing and fabricating fibers with customized surface contour, the ability to manipulate filament diameter from submicron scale to a couple of orders of magnitude larger scale, and the amenable porosity gradient across the carbon wall by diffusion controlled functionalization of precursor. The geometry of fiber cross-section was tailored by using bicomponent melt-spinning with shaped dies and controlling the melt-processing of the precursor polymer. Circular, trilobal, gear-shaped hollow fibers, and solid star-shaped carbon fibers of 0.5 - 20 um diameters, either in self-assembled bundle form, or non-bonded loose filament form, were produced by carbonizing functionalized-polyethylene fibers. Prior to carbonization, melt-spun fibers were converted to a char-forming mass by optimizing the sulfonation on polyethylene macromolecules. The fibers exhibited distinctly ordered carbon morphologies at the outside skin compared to the inner surface or fiber core. Such order in carbon microstructure can be further tuned by altering processing parameters. Partially sulfonated polyethylene-derived hollow carbon fibers exhibit 2-10 fold surface area (50-500 m2/g) compared to the solid fibers (10-25 m2/g) with pore sizes closer to the inside diameter of the filaments larger than the sizes on the outer layer. These specially functionalized carbon fibers hold promise for extraordinary performance improvements when used, for example, as composite reinforcements, catalyst support media, membranes for gas separation, CO2 sorbents, and active electrodes and current collectors for energy storage applications.

Hunt, Marcus A [ORNL; Saito, Tomonori [ORNL; Brown, Rebecca H [ORNL; Kumbhar, Amar S [University of North Carolina, Chapel Hill; Naskar, Amit K [ORNL

2012-01-01

175

Why do polyethylene crystals have sectors?  

PubMed Central

High-resolution (3.7 A in optical diffraction) electron microscope images have been obtained from a series of n-paraffin monolamellar crystals with chain lengths from n-C36H74 to n-C82H166. The higher molecular weight specimens, which do not undergo chain folding, form sectorized crystals and the molecular packing is found to include alternate bands of untilted and tilted chains along <130>. Their widths are consistent with those of Bragg fringe widths in bright-field images obtained at lower magnification. The chain tilt axis is near d*110. Lower molecular weight paraffins form nonsectorized crystals where the chains are generally untilted with occasional small inclinations around nonspecific axes. Surface decoration of the longer alkanes with polyethylene crystallites, first of all, reveals three preferred polyethylene crystal rod orientations ([100] plus two perpendicular to [110]) instead of the two commonly found for the lower alkane. Control studies on solid-solution crystals reveal that the third [100] orientation is a result of slight surface roughness due to unequal chain lengths or surface protrusions of chains; the new decoration is also randomly distributed. For pure n-C60H122 lamellae, however, suggestions of regular bands containing rods along [100], due to surface discontinuities along <130>, can also be seen. In contrast with polyethylene, these data suggest that crystal sectorization may be a function of chain-stem packing alone and that chain folds may play merely a secondary role in the polymer--e.g., by directing the collapse of pyramidal crystals on a flat surface. Images

Dorset, D L; Hanlon, J; McConnell, C H; Fryer, J R; Lotz, B; Wittmann, J C; Beckmann, E; Zemlin, F

1990-01-01

176

Complete polyethylene wear-through and secondary breakage of the expansion cup in a ceramic-polyethylene total hip arthroplasty  

Microsoft Academic Search

Introduction  Catastrophic polyethylene failure is an uncommon complication of ceramic-on-polyethylene total hip arthroplasty (THA) because\\u000a of the favourable tribological characteristics of these implants. We present a case of a 50-year-old woman who formerly underwent\\u000a bilateral ceramic-on-polyethylene THA with expansion acetabular cups and eleven years later presented with unilateral THA\\u000a dislocation, secondary to catastrophic polyethylene failure and metal shell fracture.\\u000a \\u000a \\u000a \\u000a Case presentation  The

Massimo Mariconda; Alessandro Silvestro; Gelsomina Mansueto; Domenico Marinò

2010-01-01

177

Surface modification on polyethylene terephthalate films with 2-methacryloyloxyethyl phosphorylcholine.  

PubMed

In this study, the surface of polyethylene terephthalate (PET) was modified to improve the protein and cell adhesion behavior with low temperature ammonia plasma treatment followed by 2-methacryloyloxyethyl phosphorylcholine (MPC) grafting. The x-ray photoelectron spectroscopy (XPS) results showed that the -COO(-), -N-C=O and -P-O-H groups were successfully incorporated onto the sample surface after MPC grafting. Furthermore, formation of new bonds, -N= and N-H on the sample surface grafted with MPC was recorded by Fourier transform infrared spectroscopy (FTIR). A large number of spherical particles at submicron to nanometer scale were also observed on the surface by atomic force microscopy (AFM). The cell adhesion experiments on PET film surfaces were evaluated and the highly hydrophilic surfaces could not promote cell adhesion and spreading. All results achieved in this study have clearly indicated that the method combining low temperature ammonia plasma treatment and MPC grafting is an effective way of producing a suitably hydrophilic PET surface with the capability of weakening the protein adsorption greatly. PMID:23623130

Zheng, Zhiwen; Ren, Li; Zhai, Zhichen; Wang, Yingjun; Hang, Fei

2013-07-01

178

A PEGylation technology of L-asparaginase with monomethoxy polyethylene glycol-propionaldehyde.  

PubMed

Polyethylene glycol (PEG) conjugation technology has been successfully applied to improve the performance of protein drugs. In this study, L-asparaginase was N-terminal site-specifically modified by alkylating PEG with monomethoxy polyethylene glycol-propionaldehyde (mPEG-ALD20000). The optimum reaction parameters were determined as pH 5.0, a molar ratio of mPEG-ALD2000 to L-asparaginase of 10:1, a reaction time of 16 h and temperature of 25 degrees C. PEG-L-asparaginase (PEG-L-ASNase) was isolated and purified with consecutive anion-exchange (XK, 16 x 20 cm, Q Sepharose FF) and gel-filtration (Tricorn, 10 x 600 cm, Sephacryl S-300 HR) chromatography, respectively. PEG-L-ASNase retained 43.5% of its activity and the N-terminal amino groups were modified to an extent of 3.67%. PMID:22888537

Wang, Bochu; Cao, Yang; Chi, Shaoping; Lou, Deshuai

2012-01-01

179

21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Polyethylene glycol (mean molecular weight 200-9...Multipurpose Additives § 172.820 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene glycol identified in this...

2009-04-01

180

78 FR 48147 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet, and Strip...countervailing duty (CVD) order on polyethylene terephthalate film, sheet and strip...gauges of raw, pretreated, or primed polyethylene terephthalate film, sheet and...

2013-08-07

181

78 FR 50376 - Polyethylene Retail Carrier Bags From Thailand: Final Results of Antidumping Duty Administrative...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...1\\ See Polyethylene Retail Carrier Bags from...

2013-08-19

182

75 FR 23670 - Polyethylene Retail Carrier Bags from the Socialist Republic of Vietnam: Countervailing Duty Order  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration (C-552-805) Polyethylene Retail Carrier Bags from the Socialist...issuing a countervailing duty order on polyethylene retail carrier bags (PRCBs) from...investigation of PRCBs from Vietnam. See Polyethylene Retail Carrier Bags from the...

2010-05-04

183

78 FR 48143 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Antidumping Duty Administrative Review: Polyethylene Terephthalate Film, Sheet, and...

2013-08-07

184

21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Polyethylene glycol (mean molecular weight 200-9...Multipurpose Additives § 172.820 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene glycol identified in this...

2010-01-01

185

78 FR 48651 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan; Preliminary Results of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet and...

2013-08-09

186

76 FR 76948 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Countervailing...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet, and Strip...results of the administrative review of polyethylene terephthalate film, sheet and strip...Background Since the issuance of Polyethylene Terephthalate Film, Sheet, and...

2011-12-09

187

78 FR 76280 - Polyethylene Retail Carrier Bags From the People's Republic of China: Affirmative Preliminary...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-886] Polyethylene Retail Carrier Bags From the People's...determines that imports of unfinished polyethylene retail carrier bags (PRCBs) from...1\\ See Antidumping Duty Order: Polyethylene Retail Carrier Bags From the...

2013-12-17

188

76 FR 30102 - Polyethylene Retail Carrier Bags From Thailand: Preliminary Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...Thailand. See Antidumping Duty Order: Polyethylene Retail Carrier Bags From...

2011-05-24

189

76 FR 57715 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Revocation of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...existing antidumping duty order on polyethylene terephthalate film, sheet, and...

2011-09-16

190

77 FR 14493 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty administrative review of polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

2012-03-12

191

76 FR 12700 - Polyethylene Retail Carrier Bags From Thailand: Final Results of Antidumping Duty Administrative...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags from Thailand...Commerce (the Department) published Polyethylene [[Page 12701

2011-03-08

192

75 FR 49902 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Preliminary Results of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

2010-08-16

193

76 FR 71512 - Polyethylene Terephthalate Film, Sheet, and Strip From Korea: Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

2011-11-18

194

77 FR 2959 - Polyethylene Retail Carrier Bags From the People's Republic of China: Rescission of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-886] Polyethylene Retail Carrier Bags From the People's...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...PRC. See Antidumping Duty Order: Polyethylene Retail Carrier Bags From the...

2012-01-20

195

78 FR 88 - Polyethylene Retail Carrier Bags From the People's Republic of China: Rescission of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-886] Polyethylene Retail Carrier Bags From the People's...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...August 31, 2012, the petitioners, the Polyethylene Retail Carrier Bag Committee and...

2013-01-02

196

78 FR 35245 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

2013-06-12

197

76 FR 68137 - Polyethylene Retail Carrier Bags From Thailand: Amended Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...Commerce (the Department) published Polyethylene Retail Carrier Bags From Thailand...to 19 CFR 351.224(c) from the Polyethylene Retail Carrier Bag Committee and...

2011-11-03

198

75 FR 16428 - Polyethylene Retail Carrier Bags from the Socialist Republic of Vietnam: Final Affirmative...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-552-805] Polyethylene Retail Carrier Bags from the Socialist...provided to producers and exporters of polyethylene retail carrier bags (PRCBs) from...Register on September 4, 2009. See Polyethylene Retail Carrier Bags from the...

2010-04-01

199

75 FR 34699 - Polyethylene Retail Carrier Bags from Thailand: Rescission of Antidumping Duty Administrative...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags from Thailand...review of the antidumping duty order on polyethylene retail carrier bags from Thailand...in response to requests from the Polyethylene Retail Carrier Bag Committee and...

2010-06-18

200

76 FR 72676 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...interested parties to comment. See Polyethylene Terephthalate Film, Sheet, and...

2011-11-25

201

75 FR 40784 - Polyethylene Terephthalate Film, Sheet, and Strip from the Republic of Korea: Preliminary Results...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...until no later than July 7, 2010. See Polyethylene Terephthalate Film, Sheet and...

2010-07-14

202

76 FR 76941 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

2011-12-09

203

78 FR 47276 - Polyethylene Terephthalate (PET) Film, Sheet, and Strip From India: Final Results of the...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate (PET) Film, Sheet...of the countervailing duty order on polyethylene terephthalate (PET) film, sheet...Notice of Countervailing Duty Order: Polyethylene Terephthalate Film, Sheet, and...

2013-08-05

204

76 FR 59999 - Polyethylene Retail Carrier Bags From Thailand: Final Results of Antidumping Duty Administrative...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags from Thailand...Commerce (the Department) published Polyethylene Retail Carrier Bags From...

2011-09-28

205

75 FR 75172 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...interested parties to comment. See Polyethylene Terephthalate Film, Sheet, and...

2010-12-02

206

76 FR 27005 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Initiation and...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...of Sales at Less Than Fair Value: Polyethylene Terephthalate Film, Sheet, and...

2011-05-10

207

77 FR 73428 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Antidumping Duty Administrative Review: Polyethylene Terephthalate Film, Sheet, and...

2012-12-10

208

78 FR 9668 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...1\\ See Polyethylene Terephthalate Film, Sheet, and...

2013-02-11

209

76 FR 9753 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

2011-02-22

210

76 FR 75870 - Polyethylene Terephthalate Film, Sheet, and Strip From Korea: Notice of Rescission of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, [[Page...revocation of the antidumping duty order on polyethylene terephthalate film, sheet, and...

2011-12-05

211

78 FR 28192 - Polyethylene Retail Carrier Bags From Thailand: Preliminary Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...subject to the antidumping duty order is polyethylene retail carrier bags, which are...

2013-05-14

212

76 FR 50456 - Notice of Final Results of Antidumping Duty Changed Circumstances Review: Polyethylene...  

Federal Register 2010, 2011, 2012, 2013

...Duty Changed Circumstances Review: Polyethylene Terephthalate Film, Sheet, and Strip...regard to the antidumping duty order on polyethylene terephthalate film, sheet, and strip...of Sales at Less Than Fair Value: Polyethylene Terephthalate Film, Sheet, and...

2011-08-15

213

76 FR 11203 - Polyethylene Retail Carrier Bags From the People's Republic of China: Rescission of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-886] Polyethylene Retail Carrier Bags From the People's...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...PRC. See Antidumping Duty Order: Polyethylene Retail Carrier Bags From the...

2011-03-01

214

78 FR 50029 - Polyethylene Terephthalate Film, Sheet and Strip From Brazil: Preliminary Results of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...Antidumping Duty Administrative Review of Polyethylene Terephthalate Film, Sheet and...

2013-08-16

215

75 FR 80457 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...through December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

2010-12-22

216

78 FR 78333 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Antidumping Duty Administrative Review: Polyethylene Terephthalate Film, Sheet, and...

2013-12-26

217

75 FR 36359 - Polyethylene Retail Carrier Bags From Thailand: Extension of Time Limit for Preliminary Results...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...the antidumping duty order on polyethylene retail carrier bags from Thailand. See Antidumping Duty Order: Polyethylene Retail Carrier Bags From...

2010-06-25

218

75 FR 61128 - Polyethylene Retail Carrier Bags From Malaysia: Final Results of Antidumping Duty Administrative...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-557-813] Polyethylene Retail Carrier Bags From Malaysia...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...and invited parties to comment. See Polyethylene Retail Carrier Bags From...

2010-10-04

219

75 FR 53953 - Polyethylene Retail Carrier Bags From Thailand: Preliminary Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...Thailand. See Antidumping Duty Order: Polyethylene Retail Carrier Bags From...

2010-09-02

220

77 FR 19634 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission of Countervailing Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty (CVD) order on polyethylene terephthalate film, sheet and strip...respect to Vacmet and Polypacks. See Polyethylene Terephthalate Film, Sheet and...

2012-04-02

221

75 FR 16434 - Polyethylene Retail Carrier Bags From the Socialist Republic of Vietnam: Final Determination of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-552-806] Polyethylene Retail Carrier Bags From the Socialist...Department'') has determined that polyethylene retail carrier bags (``PRCBs...LTFV, as provided in the Act. See Polyethylene Retail Carrier Bags From the...

2010-04-01

222

75 FR 49900 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Preliminary Results of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...order on PET film from Brazil. See Polyethylene Terephthalate Film, Sheet, and...

2010-08-16

223

77 FR 9892 - Polyethylene Terephthalate Film, Sheet and Strip from India: Preliminary Intent to Rescind...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty (CVD) order on polyethylene terephthalate film, sheet and strip...respect to Vacmet and Polypacks. See Polyethylene Terephthalate Film, Sheet and...

2012-02-21

224

76 FR 70965 - Polyethylene Retail Carrier Bags From Thailand: Correction to the Amended Final Results of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags from Thailand for...review of the antidumping duty order on polyethylene retail carrier bags from...

2011-11-16

225

78 FR 79400 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Initiation...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Background The antidumping duty order on polyethylene terephthalate film, sheet, and...

2013-12-30

226

75 FR 33772 - Polyethylene Retail Carrier Bags From Malaysia: Preliminary Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-557-813] Polyethylene Retail Carrier Bags From Malaysia...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...Malaysia. See Antidumping Duty Order: Polyethylene Retail Carrier Bags From...

2010-06-15

227

75 FR 14423 - Polyethylene Terephthalate Film, Sheet and Strip from Taiwan: Extension of Time Limit for...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-837] Polyethylene Terephthalate Film, Sheet and Strip...antidumping duty order on polyethylene terephthalate film, sheet and strip...antidumping order on polyethylene terephthalate film, sheet and...

2010-03-25

228

77 FR 3730 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, in Part, of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...duty (AD) order on polyethylene terephthalate film, sheet and strip...September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

2012-01-25

229

77 FR 1668 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, in Part, of...  

Federal Register 2010, 2011, 2012, 2013

...Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...duty (CVD) order on polyethylene terephthalate film, sheet and strip...September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

2012-01-11

230

75 FR 69629 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Extension...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...administrative review on polyethylene terephthalate film, sheet, and strip...of this review. See Polyethylene Terephthalate Film, Sheet, and...

2010-11-15

231

Biological effects summary report: polyethylene glycol  

SciTech Connect

An evaluation of the health effects of polyethylene glycol (PEG) was made to assess its potential use as a substitute for di(2-ethylhexyl) phthalate, which is used as test aerosol in quantitative fit testing of respirators. The polyethylene glycols of primary interest are those whose average molecular weights are between 200 and 600. PEG has a very low acute and chronic toxicity in animals. Toxic effects to the kidney resulting from high doses have been observed in laboratory animals and in burn patients whose injured skin was treated topically with PEG. It is unlikely that healthy people exposed to test aerosols of PEG would encounter such risks particularly at such low concentrations. No significant adverse effects from PEG have been observed in inhalation toxicology studies, carcinogen testing, or mutagen assays. Since the PEGs present no significant health hazard in the workplace, only a nuisance dust exposure limit of 10 mg/m/sup 3/ for total dust and 5 mg/m/sup 3/ for respirable dust is recommended. No standard for protection of human health is deemed warranted at this time. Therefore, PEG 400 may be used safely for quantitative fit testing of respirators without concern for adverse effects in healthy subjects.

Silverstein, B.D.; Furcinitti, P.S.; Cameron, W.A.; Brower, J.E.; White, O. Jr.

1984-01-01

232

Chemical Method for the Determination of Starch in Polyethylene  

Microsoft Academic Search

A chemical\\/spectrophotometric procedure has been developed that allows the determination of starch and some modified starches (as glucosyl residues) in polyethylene films and pellets. The method uses samples containing up to 60 mg polyethylene and determines the anhydrous starch content of samples possessing starch loads in the range typically encountered with degradable plastics (5–40%). The method consists of dissolution of

Alfred R. Fratzke; Wei Sung; Roque L. Evangelista; Žkivko L. Nikolov

1991-01-01

233

Effect of Thermal Aging on Breakdown Strength of Polyethylene  

Microsoft Academic Search

Effect of thermal aging on breakdown strength of low-density polyethylene has been investigated with fixed electrodes. Thermal aging of polyethylene induces oxidation and rearrangement of molecular chains which cause an increase of its crystallinity and a decrease in the long period. In the initial stages of thermal aging, the amorphous parts grow strained with an increase in the crystallinity, and

Shoshi Katakai; Kichinosuke Yahagi

1985-01-01

234

Thermomechanical degradation in the preparation of polyethylene blends  

Microsoft Academic Search

A Haake Rheocord 90 melt blender was used to prepare several types of commercial polyethylene samples intended for studies on blends as well as to condition the pure components. The objective was to assess whether thermomechanical degradation of polyethylenes was occurring during the “conditioning’’ process and, if so, to characterize its nature and to find ways to prevent the degradation.

Ibnelwaleed A. Hussein; Kam Ho; Shivendra K. Goyal; Elizabeth Karbashewski; Michael C. Williams

2000-01-01

235

Plasma induced grafting of styrene onto nascent polyethylene powder  

Microsoft Academic Search

In this paper, the graft copolymers of styrene to nascent linear polyethylene reactor powders were prepared through plasma graft polymerization. The grafting reaction was initiated by the alkyl radicals formed on the surface of nascent polyethylene with plasma treatment as indicated by electron spin resonance spectra. In graft copolymerization by alkyl radicals, the grafting yield increased with either the plasma

Jun Tian; Xiao Lin; Baotong Huang; Jiping Xu

1995-01-01

236

Compatibilisation of polyethylene\\/ground tyre rubber blends by ? irradiation  

Microsoft Academic Search

In the present work, ? irradiation is used for the in situ compatibilisation of blends of recycled high density polyethylene (rHDPE) and ground tyre rubber (GTR) powder. The expected compatibilisation mechanism involves the formation of free radicals, leading to chain scission within rubber particles, crosslinking of polyethylene matrix and co-crosslinking between the two blend components at the interface. While uncompatibilised

R. Sonnier; E. Leroy; L. Clerc; A. Bergeret; J. M. Lopez-Cuesta

2006-01-01

237

Polyethylene magnetic nanoparticle: a new magnetic material for biomedical applications  

NASA Astrophysics Data System (ADS)

Polyethylene magnetic nanoparticles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. Low molecular weight polyethylene wax and maghemite were used for forming the composite particles. These particles were further coated with avidin. The nanoparticles are characterized using STEM, AFM and SQUID. Nanomagnetic particles were found to have two distinct morphologies and have superparamagnetic properties.

Chatterjee, Jhunu; Haik, Yousef; Chen, Ching-Jen

2002-05-01

238

SECURING CONTAINERIZED HAZARDOUS WASTES WITH POLYETHYLENE RESIN AND FIBERGLASS ENCAPSULATES  

EPA Science Inventory

This study investigates the fabrication and use of polyethylene resin and fiberglass to encapsulate and secure containerized hazardous wastes. Laboratory-scale encapsulates of composite structure were made from powdered, high-density polyethylene (HDPE) and epoxy-resin-wetted fib...

239

Composites of Low-Density Polyethylene and Castor Presscake  

Microsoft Academic Search

Composites of low density polyethylene were prepared by melt mixing in a co-rotating twin screw extruder. Castor presscake, a biodiesel process co-product, was used as filler for the polyethylene composites. Different concentrations of this filler were added to the polymer matrix. Melt flow index and. mechanical properties were measured by following standardized tests. The results showed that the addition of

Rodrigo R. Stork; Marisa C. G. Rocha

2010-01-01

240

Polyethylene magnetic nanoparticle: a new magnetic material for biomedical applications  

Microsoft Academic Search

Polyethylene magnetic nanoparticles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. Low molecular weight polyethylene wax and maghemite were used for forming the composite particles. These particles were further coated with avidin. The nanoparticles are characterized using STEM, AFM and SQUID. Nanomagnetic particles were found to have two distinct morphologies and have superparamagnetic properties.

Jhunu Chatterjee; Yousef Haik; Ching-Jen Chen

2002-01-01

241

Polyethylene encapsulation full-scale technology demonstration. Final report  

Microsoft Academic Search

A full-scale integrated technology demonstration of a polyethylene encapsulation process, sponsored by the US Department of Energy (DOE) Office of Technology Development (OTD), was conducted at the Environmental & Waste Technology Center at Brookhaven National Laboratory (BNL.) in September 1994. As part of the Polymer Solidification National Effort, polyethylene encapsulation has been developed and tested at BNL as an alternative

P. D. Kalb; P. R. Lageraaen

1994-01-01

242

Space charge measurement techniques and space charge in polyethylene  

Microsoft Academic Search

Recently, several new techniques such as LIPP, PIPS, PEA and TP methods have been developed to measure directly the space charge distributions in insulating polymers. Many papers have been published on space charge in insulating materials. In this paper, the space charge measurement techniques and space charge in polyethylene are reviewed. The space charge distributions in polyethylene depend strongly upon

T. Mizutani

1994-01-01

243

Atmospheric Dielectric Barrier Discharge Treatments of Polyethylene, Polypropylene, Polystyrene and Poly(ethylene terephthalate) for Enhanced Adhesion  

Microsoft Academic Search

A critical review of published studies investigating the dielectric barrier discharge (DBD) treatment of four polymers widely employed in the packaging sector, namely: polyethylene (PE), polypropylene (PP), poly(ethylene terephthalate) (PET) and polystyrene (PS) is presented. The DBD treatment process operates at atmospheric pressure in air, and thereby offers a low cost method of enhancing the surface properties of polymers. The

D. Dixon; B. J. Meenan

2012-01-01

244

Direct measurement of molecular level adhesion between poly(ethylene terephthalate) and polyethylene films: determination of surface and interfacial energies  

Microsoft Academic Search

The strength of an adhesive bond depends on the thermodynamic work of adhesion, among other properties. In this paper, we report the direct measurement of the thermodynamic work of cohesion and adhesion between poly(ethylene terephthalate) (PET) and polyethylene (PE) films. The pull-off force between polymer surfaces was measured using the surface forces apparatus (SFA). Thermodynamic work of adhesion was determined

V. Mangipudi; M. Tirrell; A. V. Pcius

1994-01-01

245

The effect of frictional heating and forced cooling on the serum lubricant and wear of UHMW polyethylene cups against cobalt-chromium and zirconia balls.  

PubMed

Hip simulator tests of femoral balls of cobalt-chromium alloy or zirconia against acetabular cups of UHMW polyethylene were run with and without a coolant circulated inside the femoral balls. Without cooling, the wear of polyethylene against zirconia was about 48% lower than with cobalt-chromium alloy, but the steady-state temperature of the zirconia ball was higher (55 degrees C vs. 41 degrees C), and there was more precipitation of protein from the serum, which sometimes formed an adherent layer on the surface of the zirconia. Circulating coolant at 1-20 degrees C markedly reduced the bearing temperatures and the protein precipitation. With coolant at 4 degrees C, wear of the polyethylene against cobalt-chromium alloy was about 26% lower than against zirconia, but the macroscopic and microscopic appearance of the worn polyethylene surfaces were unlike that typically generated in vivo. With or without coolant, the morphology of the polyethylene wear debris was comparable to that generated in vivo, but the ratio of fibrillar to granular debris was higher at the reduced temperature. These results suggested that circulating coolant at an appropriate temperature could avoid overheating (due to non-stop running of the simulator), preventing excessive protein precipitation while providing wear surfaces and wear debris with morphologies closely comparable to those generated in vivo. PMID:12895577

Liao, Y-S; McKellop, H; Lu, Z; Campbell, P; Benya, P

2003-08-01

246

IPN-like systems based on polyethylene and methacrylates: 2. Polyethylene—butyl methacrylate copolymer IPNs  

Microsoft Academic Search

IPN-like materials based on polyethylene and butyl methacrylate copolymers were prepared by in situ polymerization above the melting point of PE. A co-continuous phase morphology was observed. The use of butyl methacrylate-co-methyl methacrylate and a low content of methacrylate crosslinker resulted in a fine dispersion of the IPN components in one another. Grafting reactions during the synthesis of the IPN-like

U. Schulze; A. Fiedlerova; G. Pompe; E. Meyer; A. Janke; J. Pionteck; E. Borsig

1998-01-01

247

Modification of polyethylene terephthalate by proton irradiation  

NASA Astrophysics Data System (ADS)

Polyethylene terephthalate (PET) films were irradiated with 3 MeV proton beams at different fluences. The microhardness, electrical, thermal and structural studies were carried out using microhardness tester, LCR meter, thermogravimetric analysis (TGA) and FTIR spectroscopy. Vickers' hardness has been observed to increase with the fluence. The true bulk hardness of the film was obtained at loads greater than 400 mN. The AC electrical conductivity is practically unaffected by irradiation up to a frequency of 10 kHz, but it is found to increase exponentially at a frequency of 300 kHz. The loss factor and dielectric constant are observed to change appreciably with the fluence. It is observed that there is no significant change in the stability of the polymer up to the fluence of 1014 ions cm(-2) as revealed by TGA and FTIR spectroscopy.

Singh, N. L.; Shah, N.; Desai, C. F.; Singh, K. P.; Arora, S. K.

2004-08-01

248

Commercialization of the polyethylene macroencapsulation process  

SciTech Connect

With support from the US Department of Energy Office of Science and Technology (DOE OST) and assistance from Brookhaven National Laboratory (BNL), Envirocare of Utah, Inc. (Envirocare) is commercializing the polyethylene macroencapsulation process. Envirocare, currently the only commercially licensed mixed waste disposal facility in the US, will initially demonstrate the process by treating and disposing up to 227,000 kg (500,000 lbs) of radioactively contaminated lead. This waste, considered mixed due to both radioactive and hazardous constituents, is currently being stored at various sites throughout the DOE complex. Following this initial work for DOE, the process will be available for the treatment of other applicable wastes. Throughout commercialization of this process, BNL has provided Envirocare with technical support for engineering and permitting.

Lageraaen, P.R.; Kalb, P.D. [Brookhaven National Lab., Upton, NY (United States); Hellstrom, G.W.; Vance, J.K. [Envirocare of Utah, Inc., Salt Lake City, UT (United States)

1998-01-01

249

Polyethylene glycolated PAMAM dendrimers-Efavirenz conjugates  

PubMed Central

Aim: The preparation of novel PEGylated PAMAM (poly-amidoamine) dendrimers for delivery of anti-HIV drug Efavirenz is reported. Method and Materials: About 5.0 G PAMAM dendrimers are prepared by ethylene diamine core via Michael addition by divergent method. PEGylation is done by polyethylene glycol 600 using epichlorhydrin as linker. PEGylated 5.0 G PAMAM dendrimers loaded with Efavirenz (EFV) are evaluated for FTIR, DSC, SEM, drug release, and stability studies. Results and Conclusion: From the results it is proved that this method is less time consuming, inexpensive, and reproducible. Drug-release studies indicate, PEGylated 5.0 G PAMAM-EFV dendrimers have shown prolonged drug-release property.

Pyreddy, Suneela; Kumar, Pandurangan Dinesh; Kumar, Palanirajan Vijayaraj

2014-01-01

250

Immobilization of silver nanoparticles on polyethylene terephthalate  

PubMed Central

Two different procedures of grafting with silver nanoparticles (AgNP) of polyethylene terephthalate (PET), activated by plasma treatment, are studied. In the first procedure, the PET foil was grafted with biphenyl-4,4?-dithiol and subsequently with silver nanoparticles. In the second one, the PET foil was grafted with silver nanoparticles previously coated with the same dithiol. X-ray photoelectron spectroscopy and electrokinetic analysis were used for characterization of the polymer surface at different modification steps. Silver nanoparticles were characterized by ultraviolet-visible spectroscopy and by transmission electron microscopy (TEM). The first procedure was found to be more effective. It was proved that the dithiol was chemically bonded to the surface of the plasma-activated PET and that it mediates subsequent grafting of the silver nanoparticles. AgNP previously coated by dithiol bonded to the PET surface much less.

2014-01-01

251

Vacuum Outgassing of High Density Polyethylene  

SciTech Connect

A combination of thermogravimetric analysis (TGA) and temperature programmed decomposition (TPD) was employed to identify the outgassing species, the total amount of outgassing, and the outgassing kinetics of high density polyethylene (HDPE) in a vacuum environment. The isoconversional kinetic analysis was then used to analyze the outgassing kinetics and to predict the long-term outgassing of HDPE in vacuum applications at ambient temperature. H{sub 2}O and C{sub n}H{sub x} with n as high as 9 and x centering around 2n are the major outgassing species from solid HDPE, but the quantities evolved can be significantly reduced by vacuum baking at 368 K for a few hours prior to device assembly.

Dinh, L N; Sze, J; Schildbach, M A; Chinn, S C; Maxwell, R S; Raboin, P; McLean II, W

2008-08-11

252

Polyethylene welding by pulsed visible laser irradiation  

NASA Astrophysics Data System (ADS)

Laser welding of plastics is a relatively new process that induces locally a fast polymer heating. For most applications, the process involves directing a pulsed beam of visible light at the weld joint by going through one of the two parts. This is commonly referred to as "through transmission visible laser welding". In this technique, the monochromatic visible light source uses a power ns pulsed laser in order to irradiate the joint through one part and the light is absorbed in the vicinity of the other part. In order to evaluate the mechanical resistance of the welded joint, mass quadrupole spectrometry, surface profilometry, microscopy techniques and mechanical shear tests were employed. The welding effect was investigated as a function of the laser irradiation time, nature of the polyethylene materials and temperature.

Torrisi, L.; Caridi, F.; Visco, A. M.; Campo, N.

2011-01-01

253

High Magnetization Polyethylene Glycol Coated Nanoparticles  

NASA Astrophysics Data System (ADS)

High magnetization nanoparticles coated with a biocompatible polymer or poly-saccharide layer are required for biomedical applications such as targeted drug delivery, MRI contrast enhancement and hyperthermia treatments. This paper discusses the fabrication and characterization of iron nanoparticles coated with carboxyl terminated polyethylene glycol for future biomedical applications. Electron microscopy reveals nanoparticles ranging from 10 to 50 nm in size that have a body centered cubic structure characteristic of alpha Fe. Mossbauer spectroscopy reveals the typical sextet expected for Fe with two different hyperfine fields reminiscent of a core shell morphology indicating that there are two distinct Fe sites. The coated nanoparticles are soft ferromagnets with coercivity below 100 Oe and a saturation magnetization of 50 emu/g as shown by SQUID and vibrating sample magnetometry. Optimization studies are underway and the results will be reported.

Bonder, M. J.; Papaefthymiou, V.

2005-03-01

254

Biochemical Applications of Poly(Ethylene Glycol)  

NASA Astrophysics Data System (ADS)

The literature data on the use of poly(ethylene glycol) (PEG) in biochemistry and molecular biology are analysed from the standpoint of the physical chemistry of polymers. The exclusion properties of PEG, used as a factor influencing the rate of enzymatic reactions, the intra- and intermolecular transitions in polymers, and biopolymer precipitation and crystallisation processes are examined. The suitability of three-component PEG-dextran-water mixtures for the purification and separation of mixtures of biopolymers and for analytical purposes as well as the possibility of using functional derivatives of PEG in immunological research and for the immobilisation of enzymes are discussed. A special section is devoted to the synthesis of PEG derivatives containing different functional groups at the ends of the polymer chain. The surface-active properties of PEG are examined. The bibliography includes 78 references.

Topchieva, Irina N.

1980-03-01

255

Facial skeletal reconstruction using porous polyethylene implants.  

PubMed

A retrospective review of clinical outcomes was performed to determine the clinical utility and morbidity associated with the use of porous polyethylene facial implants. Three hundred seventy implants were placed in 162 consecutive patients, in 178 operations performed in 11 years. The number of patients, the number of implants used, and the average follow-up period were categorized according to the cause of the deformity. The resultant distribution was as follows: acquired (tumor-related), 17 patients, 39 implants, and 30 months; congenital, eight patients, 31 implants, and 92 months; aesthetic, 39 patients, 97 implants, and 24 months; secondary posttraumatic, 48 patients, 139 implants, and 37 months; and acute trauma (internal orbit reconstruction), 50 patients, 64 implants, and 9 months. The distribution of implants according to location was as follows: frontal, 21; temporal, 30; internal orbit, 145; infraorbital rim, 28; malar, 58; paranasal, 29; nasal, 13; mandible, 24; and chin, 22. The combined average follow-up period per patient was 27 months (range, immediate postoperative period to 11 years). All implants were placed in the subperiosteal plane, and the majority were fixed with titanium screws. Antibiotics were administered perioperatively. No implants were extruded or migrated, formed clinically apparent capsules, or caused symptoms attributable to bioincompatibility. The overall reoperation rate was 10 percent (n = 16), which included operations to remove implants because of acute infections (2 percent, n = 3) or a late infection (1 percent, n = 1), to remove implants causing displeasing contours (2 percent, n = 3), and to improve contours (6 percent, n = 9). Porous polyethylene implants have biomaterial properties favorable for facial skeletal augmentation. Screw application of the implants to the skeleton allows precise predictable contouring, thus limiting the need for revisional surgical procedures. PMID:12711941

Yaremchuk, Michael J

2003-05-01

256

Fabrication and characterization of plasma-polymerized poly(ethylene glycol) film with superior biocompatibility.  

PubMed

A newly fabricated plasma-polymerized poly(ethylene glycol) (PP-PEG) film shows extremely low toxicity, low fouling, good durability, and chemical similarity to typical PEG polymers, enabling live cell patterning as well as various bioapplications using bioincompatible materials. The PP-PEG film can be overlaid on any materials via the capacitively coupled plasma chemical vapor deposition (CCP-CVD) method using nontoxic PEG200 as a precursor. The biocompatibility of the PP-PEG-coated surface is confirmed by whole blood flow experiments where no thrombi and less serum protein adsorption are observed when compared with bare glass, polyethylene (PE), and polyethylene terephthalate (PET) surfaces. Furthermore, unlike bare PE films, less fibrosis and inflammation are observed when the PP-PEG-coated PE film is implanted into subcutaneous pockets of mice groin areas. The cell-repellent property of PP-PEG is also verified via patterning of mammalian cells, such as fibroblasts and hippocampal neurons. These results show that our PP-PEG film, generated by the CCP-CVD method, is a biocompatible material that can be considered for broad applications in biomedical and functional materials fields. PMID:23281807

Choi, Changrok; Hwang, Inseong; Cho, Young-Lai; Han, Sang Y; Jo, Dong H; Jung, Donggeun; Moon, Dae W; Kim, Eun J; Jeon, Chang S; Kim, Jeong H; Chung, Taek D; Lee, Tae G

2013-02-01

257

Monolayers of derivatized poly(L-lysine)-grafted poly(ethylene glycol) on metal oxides as a class of biomolecular interfaces  

NASA Astrophysics Data System (ADS)

We report on the design and characterization of a class of biomolecular interfaces based on derivatized poly(L-lysine)-grafted poly(ethylene glycol) copolymers adsorbed on negatively charged surfaces. As a model system, we synthesized biotin-derivatized poly(L-lysine)-grafted poly(ethylene glycol) copolymers, PLL-g-[(PEGm)(1x) (PEG-biotin)x], where x varies from 0 to 1. Monolayers were produced on titanium dioxide substrates and characterized by x-ray photoelectron spectroscopy. The specific biorecognition properties of these biotinylated surfaces were investigated with the use of radiolabeled streptavidin alone and within complex protein mixtures. The PLL-g-PEG-biotin monolayers specifically capture streptavidin, even from a complex protein mixture, while still preventing nonspecific adsorption of other proteins. This streptavidin layer can subsequently capture biotinylated proteins. Finally, with the use of microfluidic networks and protein arraying, we demonstrate the potential of this class of biomolecular interfaces for applications based on protein patterning.

Ruiz-Taylor, L. A.; Martin, T. L.; Zaugg, F. G.; Witte, K.; Indermuhle, P.; Nock, S.; Wagner, P.

2001-01-01

258

Polypropylene-Polyethylene Melts: Phase Structure Determination by Rheology  

NASA Astrophysics Data System (ADS)

Using dynamic moduli and transmission electron microscopy images the phase structure of polypropylene-polyethylene melts was studied. Blends consisting of 80% base material (polypropylene-homopolymer or ethylene-propylene copolymer) and of 20% modifier polymer (a C2/C8-elastomer, a linear low density polyethylene or a high density polyethylene) forming a two-phase structure in the melt were investigated. The influence of the viscosity ratio and the interfacial tension on the particle size of the inclusions was investigated. Both factors can be determined from dynamic moduli by using the emulsion model of Palierne [1] to calculate the interfacial tension.

Kock, Cornelia; Schausberger, A.; Aust, N.; Gahleitner, M.; Ingolic, E.

2008-07-01

259

Alumina Ceramic against Polyethylene: A long term follow up  

Microsoft Academic Search

\\u000a Between 1978 and 1990 the femoral implant was the same in four groups of patients with different function couples: alumina\\/alumina,\\u000a (AL\\/AL); alumina\\/ polyethylene (AL\\/PE); metal\\/polyethylene (Me\\/PE); zirconia\\/polyethylene (Zir\\/ PE). The aim of this study\\u000a was to compare survival rate, wear and femoral osteolysis among different couples of friction in patients with the same femoral\\u000a stem.\\u000a \\u000a \\u000a For comparison between AL\\/AL and

Ph. Hernigou; A. Nogier; A. Poignard; P. Filippini

260

Myocardial matrix-polyethylene glycol hybrid hydrogels for tissue engineering.  

PubMed

Similar to other protein-based hydrogels, extracellular matrix (ECM) based hydrogels, derived from decellularized tissues, have a narrow range of mechanical properties and are rapidly degraded. These hydrogels contain natural cellular adhesion sites, form nanofibrous networks similar to native ECM, and are biodegradable. In this study, we expand the properties of these types of materials by incorporating poly(ethylene glycol) (PEG) into the ECM network. We use decellularized myocardial matrix as an example of a tissue specific ECM derived hydrogel. Myocardial matrix-PEG hybrids were synthesized by two different methods, cross-linking the proteins with an amine-reactive PEG-star and photo-induced radical polymerization of two different multi-armed PEG-acrylates. We show that both methods allow for conjugation of PEG to the myocardial matrix by gel electrophoresis and infrared spectroscopy. Scanning electron microscopy demonstrated that the hybrid materials still contain a nanofibrous network similar to unmodified myocardial matrix and that the fiber diameter is changed by the method of PEG incorporation and PEG molecular weight. PEG conjugation also decreased the rate of enzymatic degradation in vitro, and increased material stiffness. Hybrids synthesized with amine-reactive PEG had gelation rates of 30 min, similar to the unmodified myocardial matrix, and incorporation of PEG did not prevent cell adhesion and migration through the hydrogels, thus offering the possibility to have an injectable ECM hydrogel that degrades more slowly in vivo. The photo-polymerized radical systems gelled in 4 min upon irradiation, allowing 3D encapsulation and culture of cells, unlike the soft unmodified myocardial matrix. This work demonstrates that PEG incorporation into ECM-based hydrogels can expand material properties, thereby opening up new possibilities for in vitro and in vivo applications. PMID:24334615

Grover, Gregory N; Rao, Nikhil; Christman, Karen L

2014-01-10

261

The occurrence, induction, specificity and potential effect of antibodies against poly(ethylene glycol)  

Microsoft Academic Search

Specific antibodies against poly(ethylene glycol) (anti-PEG) were induced in animals following exposure to PEG-conjugated\\u000a proteins and particles, resulting in rapid clearance of PEG-conjugated agents. In humans, induction of anti-PEG was observed\\u000a following exposure to a PEG-conjugated drug, and pre-existing anti-PEG was identified in over 25% the healthy population.\\u000a In clinical studies, the presence of anti-PEG was strongly associated with rapid

Jonathan K. Armstrong

262

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

PubMed

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

Kurien, Biji T; Scofield, R Hal

2012-01-01

263

Charge transport into interfacial space of several polyethylene laminated polymers  

Microsoft Academic Search

Contribution from both electronic and ionic is confirmed as for space charge formation at electrodes and interfaces in polyethylene\\/EVA, EPR and EPDM laminates. Interfacial charge is either positive or negative according to materials used

T. Tanaka; M. Uchiumi

1998-01-01

264

The Effects of Overfilled Polyethylene Tube Intraosseous Implants in Rats.  

National Technical Information Service (NTIS)

Polyethylene tubes obturated flush at one end and overfilled 2 mm at the opposite end with unset Grossman's cement and gutta percha were implanted in rat tibias. Microscopic evaluation of the specimens revealed that (1) the gutta percha, Grossman's sealer...

J. P. Deemer P. J. Tsaknis

1978-01-01

265

Polyethylene glycol-electrolyte solution (PEG-ES)  

MedlinePLUS

Polyethylene glycol-electrolyte solution (PEG-ES) is used to empty the colon (large intestine, bowel) before a colonoscopy (examination of the ... emptied from the colon. The medication also contains electrolytes to prevent dehydration and other serious side effects ...

266

Structure of Holographic Polymer Dispersed Polyethylene Glycol (Preprint).  

National Technical Information Service (NTIS)

Holographic polymerization (H-P) has been used to fabricate polymer dispersed liquid crystals and pattern inert nanoparticles. In this article, one- dimensional grating structures of Norland resin and polyethylene glycol (PEG) was achieved using the H-P t...

C. Y. Li H. McWilliams L. V. Natarajan M. J. Birnkrant T. J. Bunning

2006-01-01

267

Structure of Holographic Polymer-Dispersed Polyethylene Glycol (Postprint).  

National Technical Information Service (NTIS)

Holographic polymerization (H-P) has been used to fabricate polymer- dispersed liquid crystals and pattern inert nanoparticles. In this article, one- dimensional grating structures of Norland resin and polyethylene glycol (PEG) were achieved using the H-P...

C. Y. Li H. K. McWilliams L. V. Natarajan M. J. Birnkrant V. P. Toodiglia

2006-01-01

268

Suspension polymerization of poly(ethylene glycol) methacrylate: a route for swellable spherical gel beads with controlled hydrophilicity and functionality  

Microsoft Academic Search

Spherical and swellable gel beads were obtained by the suspension polymerization of poly(ethylene glycol) methacrylate macromonomer\\u000a (PEG-MA). The average size and size distribution properties, the equilibrium swelling behaviour and the protein adsorption\\u000a characteristics of PEG-MA-based gel beads were determined. In the suspension polymerization system, the organic phase including\\u000a monomer, cross-linker and diluent solution was dispersed in an aqueous medium by

A. Tuncel

2000-01-01

269

Immobilization of activated sludge in poly(ethylene glycol) by UV technology and its application in micro-polluted wastewater  

Microsoft Academic Search

A new method, ultraviolet (UV) technology, was utilized to immobilize activated sludge in poly(ethylene glycol) (PEG) gel carriers. A number of characteristics of immobilized cells, such as water content, oxygen uptake rate, and protein content, were examined, and performance in batch culture for treating synthetic micro-polluted wastewater with different C\\/N ratios and different pH values was also investigated. The bioactivity

Qiao Xiangli; Liu Zhe; Liu Zhiwei; Zeng Yinglin; Zhang Zhengjia

2010-01-01

270

Influence of tannic acid and polyethylene glycol on the excretion and digestibility of amino acids in gelatin-fed broilers  

Microsoft Academic Search

1.?A precision feeding experiment was conducted to evaluate the effects of tannic acid (TA) and polyethylene glycol (PEG) on the excretion of amino acids, and the apparent and true digestibility of gelatin protein in broilers.2.?In a 3 × 2 × 2 factorial design, ninety-six 7-week-old broiler cockerels in 8 replicates of 12 treatments, were fed on warm solution of gelatin

B. Mansoori; T. Acamovic

2009-01-01

271

Effect of synovia constituents on friction and wear of ultra-high molecular weight polyethylene sliding against prosthetic joint materials  

Microsoft Academic Search

The effect of synovia constituents, such as a serum protein and hyaluronic acid, on the friction and wear of ultra-high molecular weight polyethylene (UHMWPE) was examined in a pin-on-disk test apparatus. In this study, UHMWPE pin specimens were articulated against stainless steel (SUS316) and alumina ceramic disk specimens. Both saline and diluted bovine serum were used as lubricants. Albumin, a

Yoshinori Sawae; Teruo Murakami; Jian Chen

1998-01-01

272

New aqueous two-phase system based on cashew-nut tree gum and poly(ethylene glycol)  

Microsoft Academic Search

The characterisation of a new system based on cashew-nut tree gum, a branched acidic heteropolysaccharide found in Brazil, and poly(ethylene glycol) (PEG) was studied. Phase diagrams are provided for the PEG–cashew-nut tree gum system. The influence of PEG molecular mass, tie-line length and pH on bovine serum albumin (BSA) partition was investigated. Protein partition coefficient was little influenced by changing

L. A Sarubbo; L. A Oliveira; A. L. F Porto; H. S Duarte; A. M. A Carneiro-Leão; J. L Lima-Filho; G. M Campos-Takaki; E. B Tambourgi

2000-01-01

273

Nanoscale Intermolecular Interactions between Human Serum Albumin and Low Grafting Density Surfaces of Poly(ethylene oxide)  

Microsoft Academic Search

The net nanoscale interaction between a probe tip covalently bound with the blood plasma protein human serum albumin (HSA) and a surface of end-grafted poly(ethylene oxide) (PEO) mushrooms (Mn 50K, Flory radius RF 9 nm, contour length Lcontour 393 nm) was measured directly on approach (loading) and retract (unloading) in aqueous buffer solution using the technique of high-resolution force spectroscopy

M. A. Rixman; D. Dean; C. Ortiz

2003-01-01

274

LLCE burial container high density polyethylene chemical compatibility  

SciTech Connect

An independent chemical compatibility review of LLCE HDPE polyethylene burial containers was conducted to evaluate the container resistance to the chemicals and constituents thought to reside within the Tank Farms. The study concluded that the LLCE Burial Container fabricated from HDPE Polyethylene was a good choice for this application. The reviewer was unaware that the specification for these containers require 2 - 3 percent finely dispensed carbon black which allows long term storage outside.

Veith, E.M., Westinghouse Hanford

1996-08-20

275

CORROSION CONTROL OF DUCTILE IRON PIPE WITH POLYETHYLENE ENCASEMENT  

Microsoft Academic Search

This paper covers the history, research, development and performance of polyethylene encasement as a corrosion control measure for Cast and Ductile Iron pipe. We will review the research leading to the adoption of the American Water Works Association (AWWA) Standard for Polyethylene Encasement for Ductile-Iron Pipe Systems (ANSI\\/AWWA C105\\/A21.5) in 1972. The paper also includes a discussion of the AWWA

Normand De Agostinis

276

Grafting of side chain liquid crystal monomers onto polyethylene film  

Microsoft Academic Search

In order to obtain films of liquid crystalline polymers, a commercial polyethylene films was grafted with acryloyl chloride\\u000a using ?-irradiation, and two tolane-containing alcohols were reacted with the chloride to obtain the corresponding acrylates.\\u000a The morphology changes were studied by DSC, X-ray diffractometry and optical microscopy. The crystallinity of polyethylene\\u000a films decreased by grafting, and mesophase with spherulites was observed

Guillermina Burillo; Ruth Mendoza; Seguei Fomine; Takeshi Ogawa

1997-01-01

277

Shape memory effect of polyethylene\\/nylon 6 graft copolymers  

Microsoft Academic Search

A series of maleated polyethylene\\/nylon 6 blends with nylon as the dispersed phase was prepared at 230°C in a batched Haake mixer, and their shape memory effect was investigated. The nylon contents of the blends are in the range from 5 to 20wt%. The Molau testing was used to verify the in situ formation of polyethylene-g-nylon 6 graft copolymers bridged

Fengkui Li; Yan Chen; Wei Zhu; Xian Zhang; Mao Xu

1998-01-01

278

Curing characteristics of chlorosulphonated polyethylene and natural rubber blends  

Microsoft Academic Search

The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene\\/natural rubber (CSM\\/SMR 20 CV) and chlorosulphonated polyethylene\\/chlorinated natural rubber (CSM\\/Pergut S 40) blends were determined in the temperature range from 120 oC to 160 oC using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture

G. MARKOVI; B. RADOVANOVI; J. BUDINSKI SIMENDI

279

Non-isothermal crystallization kinetics of silane crosslinked polyethylene  

Microsoft Academic Search

The non-isothermal crystallization kinetics of silane crosslinked polyethylene (SXPE) and dicumyl peroxide (DCP) modified polyethylene (DMPE) were studied by differential scanning calorimetry at different cooling rates. Three methods, namely, the Avrami, the Ozawa, and the Mo, were applied to describe the crystallization process of virgin LLDPE, DMPE and SXPE under non-isothermal conditions. The values of half-time of crystallization t1\\/2, and

Chuanmei Jiao; Zhengzhou Wang; Xiaoming Liang; Yuan Hu

2005-01-01

280

Polyethylene/Boron Composites for Radiation Shielding Applications  

SciTech Connect

Multifunctional composites made with boron are absorbers of low energy nuetrons, and could be used for structural shielding materials. Polyethylene/boron carbide composites were fabricated using conventional polymer processing techniques, and were evaluated for mechanical and radiation shielding properties. Addition of neat boron carbide (powder and nanoparticles) to an injection molding grade HPDE showed superior mechanical properties compared to neat HDPE. Radiation shielding measurements of a 2 wt% boron carbide composite were improved over those of the neat polyethylene.

Harrison, Courtney; Grulke, Eric [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Burgett, Eric; Hertel, Nolan [Neely Nuclear Research Center, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2008-01-21

281

Primary radiation defect production in polyethylene and cellulose.  

PubMed

Irradiation effects in polyethylene and cellulose were examined using molecular dynamics simulations. The governing reactions in both materials were chain scissioning and generation of small hydrocarbon and peroxy radicals. Recombination of chain fragments and cross-linking between polymer chains were found to occur less frequently. Crystalline cellulose was found to be more resistant to radiation damage than crystalline polyethylene. Statistics on radical formation are presented and the dynamics of the formation of radiation damage discussed. PMID:23131061

Polvi, Jussi; Luukkonen, Petri; Nordlund, Kai; Järvi, Tommi T; Kemper, Travis W; Sinnott, Susan B

2012-11-29

282

Western blot membrane composed of electrospun polyvinylidene fluoride nanofiber membrane and polyethylene terephthalate sheet.  

PubMed

In a previous study, an electrospun polyvinylidene fluoride (PVDF) nanofiber membrane was developed for Western blotting. The membrane exhibited high sensitivity and high binding capacity for the detection of protein bands that was unlike that observed for conventional, microphase separation-based porous PVDF membranes. Nevertheless, the PVDF nanofiber membrane is quite expensive. The objective of this study was to develop an economical Western blot membrane using a hybrid electrospun PVDF nanofiber and polyethylene terephthalate (PET) sheet. The results showed that the detection sensitivity of the 4 gram per square meter (gsm) membrane was similar to those of the electrospun PVDF nanofiber membrane only, and the 7 gsm PVDF nanofiber membranes on a PET sheet and the electrospun PVDF nanofiber membrane. This means the protein detection sensitivity is not proportional to the thickness of the PVDF nanofiber membrane. The 4 gsm PVDF nanofiber membrane on a PET sheet can be used to detect proteins with high sensitivity and economic efficiency. PMID:23862502

Cho, Eugene; Kim, Chan; Hwang, Cheol Ho; Chang, Duck Rye; Kook, Joong-Ki

2013-06-01

283

Polarimetric studies of polyethylene terephtalate flexible substrates  

NASA Astrophysics Data System (ADS)

Polymer sheets are currently used worldwide in a wide range of applications. The manufacturing process of these sheets involves extruding machines that stretch the material in both lateral and longitudinal directions with respect to the machine direction, thus inducing birefringence. In most cases, the film obtained is optically biaxial. Polarimetric spectroscopy (Ellipsometry and Mueller Matrix) combined with conoscopic observation are the methods of choice to study these properties. In this work we report an analysis of commercially available polyethylene terephtalate (PET) films used as substrate for food packaging as well as for embedded electronic devices such as solar cells or flexible displays. Initial observation of these films through polarizing microscope in conoscopic mode reveals first the trace of optical axis plane with respect to the film surface and second, whether the optical axis is acute or not. This preliminary study allows optimal sample positioning for further polarimetric studies. The measurements and modelling are done in both reflection and transmission mode on several spectroscopic polarimetric setups from UV to NIR. The models give as a main result, the dielectric tensor of the film as well as its orientation with respect to the laboratory reference frame.

Stchakovsky, M.; Garcia-Caurel, E.; Warenghem, M.

2008-12-01

284

Morphological changes during annealing of polyethylene nanocrystals.  

PubMed

Polymer crystals are metastable and exhibit morphological changes when being annealed. To observe morphological changes on molecular scales we started from small nanometer-sized crystals of highly folded long-chain polymers. Micron-sized stripes consisting of monolayers or stacks of several layers of flat-on oriented polyethylene nanocrystals were generated via evaporative dewetting from an aqueous dispersion. We followed the morphological changes in time and at progressively higher annealing temperatures by determining the topography and viscoelastic properties of such assemblies of nanocrystals using atomic force microscopy. Due to smallness and high surface-to-volume ratio of the nanocrystals, already at 75 °C, i.e. about 60 degrees below the nominal melting point, the lateral size of the crystal coarsened. Intriguingly, this occurred without a noticeable reduction in the number of folds per polymer chain. Starting at around 110 °C, chain folds were progressively removed leading to crystal thickening. At higher temperatures, but still below the melting point, prolonged annealing allowed for surface diffusion of molten polymers on the initially bare substrate, leading eventually to the disappearance of crystals. We compared these results to the behavior of the same nanocrystals annealed in an aqueous dispersion and to bulk samples. PMID:22430366

Basu, N; Osichow, A; Mecking, S; Reiter, G

2012-03-01

285

Confinement-induced vitrification in polyethylene terephthalate  

SciTech Connect

Dynamic mechanical thermal analysis performed on cold-drawn polyethylene terephthalate (PET), cold crystallized (annealed) in the temperature interval 100-140 deg. C, reveals the presence of marginally glassy domains above the annealing temperature T{sub a}. This suggests that the thermodynamic force driving crystallization causes the structural arrest of some noncrystalline domains. The latter thus need a temperature higher than T{sub a} to completely defreeze. Differential scanning calorimetry supports this point of view. Analogous investigations on unoriented PET, cold crystallized in the same conditions, do not show the same peculiarities; thus, chain orientation is relevant to vitrification. This phenomenology is first cast in the language of thermodynamics by introducing an excess chemical potential {delta}{mu} describing the presence of structural constraints in the amorphous domains and the effect of chain orientation. For a first test of this picture, the orientation contribution to {delta}{mu} is calculated by means of the Gaussian chain model (this implicitly assumes that {delta}{mu} is related to the density fluctuations). The resulting expression is then used to discuss the structural differences between cold-drawn and unoriented PET samples reported in the literature.

Balta Calleja, F. J.; Flores, A. [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); Di Marco, G.; Pieruccini, M. [Istituto per i Processi Chimico-Fisici Sezione di Messina, CNR, Via La Farina 237, I-98123 Messina (Italy)

2007-06-01

286

Acetaldehyde residue in polyethylene terephthalate (PET) bottles.  

PubMed

A simple sample preparation technique was developed for rapid analysis of acetaldehyde residue in Polyethylene Terephthalate (PET) bottles. A laboratory-built heating system was used and coupled with gas chromatography-flame ionization detector (GC-FID) at optimized conditions. The results were a tremendous reduction of the sample preparation time from 24 hours, for the conventional method, to only one hour. The analysis took only 1.5 min with other good analytical performances i.e. a low detection limit, 0.3 ng mL(- 1) and a wide linear dynamic range, 0.3 ng mL(- 1) to 6.6 microg mL(- 1) with R(2) > 0.99. Acetaldehyde residue in freshly blown bottles were analyzed and found in the range of 0.4 to 1.1 ng mL(- 1). The results were good agreement with the conventional 24-hour airspace method (P < 0.01). The PET-bottle sampling technique was also developed to minimize the complication of sample transportation and pre-concentration. A purge and trap technique was found to be the most suitable. Then, it was implemented and compared, the results showed no significant difference (P < 0.01) with and without purge and trap. PMID:17562466

Choodum, Aree; Thavarungkul, Panote; Kanatharana, Proespichaya

2007-01-01

287

Organocatalytic decomposition of polyethylene terephthalate using triazabicyclodecene  

NASA Astrophysics Data System (ADS)

This study focuses on the organocatalytic decomposition of polyethylene terephthalate (PET) using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) to form a diverse library of aromatic amides. The reaction scheme was specifically designed to use low reaction temperatures (>150°C) and avoid using solvents during the reaction to provide a more environmentally friendly process. Of all the amines tested, PET aminolysis with aliphatic and aromatic amines demonstrated the best performance with yields higher than 72%. PET aminolysis with click functionalized and non-symmetric reagents facilitated attack on certain sites on the basis of reactivity. Finally, the performance of the PET degradation reactions with secondary amine and tertiary amine functionalized reagents yielded mixed results due to complications with isolating the product from the crude solution. Four of the PET-based monomers were also selected as modifiers for epoxy hardening to demonstrate the ability to convert waste into monomers for high-value applications. The glass transition temperatures, obtained using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) of the epoxy composite samples treated with the PET-based monomers, were generally higher in comparison to the samples cured with the basic diamines due to the hydrogen bonding and added rigidity from the aromatic amide group. Developing these monomers provides a green and commercially viable alternative to eradicating a waste product that is becoming an environmental concern.

Lecuyer, Julien Matsumoto

288

Rotational molding of pultruded profiles reinforced polyethylene  

NASA Astrophysics Data System (ADS)

The aim of this paper is the production of fiber reinforced LLDPE components by rotational molding. To this purpose, a process upgrade was developed, for the incorporation of pultruded tapes in the rotational molding cycle. Pultruded tapes, made of 50% by weight of glass fibers dispersed in a high density polyethylene(HDPE) matrix, were glued on the internal surface of a cubic mold, and rotational molding process was run using the same processing conditions used for conventional LLDPE processing. During processing, melting of LLDPE powders and of HDPE allowed to incorporate the tapes inside rotational molded LLDPE. The glass fiber reinforced prototypes were characterized in terms of mechanical properties. Plate bending tests were performed on the square faces extracted from the rotational molded product. The rotational molding products were also subjected to internal hydrostatic pressure tests up to 10 bar. In any case, no failure of the cubic samples was observed. In both cases, it was found that addition of a single pultruded strips, which corresponds to addition of about 0.6% by weight of glass fibers, involved an increase of the stiffness of the faces by about 25%.

Greco, Antonio; Maffezzoli, Alfonso; Romano, Giorgio

2014-05-01

289

Thermoelastic Expansion and Creep of Polyethylene Terephthalate and Polypyromelitimide Film and Polyethylene Terephthalate Fibers from 20 to 295K.  

National Technical Information Service (NTIS)

A quartz tube dilatometer was used to measure the lineal thermal expansion and creep of single lengths of polyethylene terephthalate (PETP) film, polypyromelitimide (PPMI) film, and PETP multifiber yarn, while stressed under constant tension. Tensions bel...

P. M. McConnel D. E. Daney J. B. Kirgis

1970-01-01

290

Surface Modification of Nanoporous Poly(?-caprolactone) Membrane with Poly(ethylene glycol) to Prevent Biofouling: Part I. Effects of Plasma Power and Treatment Time  

Microsoft Academic Search

Biofouling, a result of protein adsorption and cell adhesion on a surface, is detrimental to membrane performance. The objective of this study is to modify the polycaprolactone (PCL) membrane surface with poly(ethylene glycol) (PEG) to prevent fibroblast adhesion. To achieve this goal, oxygen plasma and PEG(400)-monoacrylate were used to graft the PEG onto the membrane surface through covalent bonding. Various

Chi Yen; Hongyan He; Zhengzheng Fei; Xulang Zhang; L. James Lee; W. S. Winston Ho

2010-01-01

291

DSC of ? -irradiated ultra-high molecular weight polyethylene and high density polyethylene of normal molecular weight  

Microsoft Academic Search

The melting and the crystallization of?-irradiated (doses: 0–6Mrad) ultra-high molecular weight nascent polyethylene (UHMWPE) and high density nascent polyethylene with normal molecular weight (NMWPE) were investigated by DSC. The heat of melting of the nascent UHMWPE (DSC degree of crystallinity, respectively) increases up to a dose of 3 Mrad, after which it slightly decreases. The heat of the second melting

L. Minkova

1988-01-01

292

Factory-Assembled Polyethylene Linings in Metal Backing Show Higher Wear Rates Compared to Equisized All-Polyethylene Sockets  

Microsoft Academic Search

Two series of cementless total hip arthroplasty with acetabular sockets of a threaded truncated cone design were compared regarding volumetric wear rates. The first series included all-polyethylene acetabular sockets of the type Endler (E-PE); in the second series, a nonmodular titanium metal-backed polyethylene (E-MB) socket with an identical outer shape to E-PE was implanted. Bearings were articulated with alumina 32-mm

Matthias W. Jentschke; Wolfgang Schultz; Gottfried H. Buchhorn

2011-01-01

293

Study of the electronic and vibrational properties of poly(ethylene terephthalate) and poly(ethylene naphthalate) films  

Microsoft Academic Search

We investigate the optical properties of biaxially stretched poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) polymer films by spectroscopic ellipsometry (SE) in a wide spectral region, from the infrared (IR) (900-3500 cm-1) to the vis-far UV (vis-fUV) (1.5-6.5 eV), in terms of their optical, electronic, and vibrational response. The stretching procedure during the fabrication of the films leads to the

A. Laskarakis; S. Logothetidis

2007-01-01

294

Spherulitic morphologies of poly(ethylene terephthalate), poly(ethylene 2,6-naphthalate), and their blend  

Microsoft Academic Search

The supermolecular structures of poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalate) (PEN), and their blend\\u000a were investigated with optical microscopy and small angle light scattering. With increasing the crystallization temperature,\\u000a incomplete spherulitic texture was developed for the PET samples. At a high crystallization temperature of 220°C, the light\\u000a scattering pattern represented a random collection of uncorrelated lamellae. The general morphological appearances for

Jong Kwan Lee; Kwang Hee Lee; Byung Suk Jin

2002-01-01

295

Dielectric relaxations in poly(ethylene terephthalate), poly(ethylene 2,6-naphthalate) and their copolymers  

Microsoft Academic Search

Dielectric spectroscopy was performed on poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), and their copolymers. Although PET and PEN have very similar chemical structure, their dielectric relaxation signatures are significantly different. PET has one subglass relaxation, beta, whereas PEN has two, beta and beta*. The beta relaxation in both polymers falls in the same frequency-temperature domain. The beta* relaxation in PEN

Shelly Packer Bravard

2000-01-01

296

Application of In Situ Microfibrillization to Recycling Ultraviolet?Aged Poly(Ethylene Terephthalate) (PET) and High Density Polyethylene (HDPE)  

Microsoft Academic Search

The potential of in situ microfibrillization for recycling ultraviolet?aged high density polyethylene (HDPE) and poly(ethylene terephthalate) (PET) mixtures was investigated. The photodegradation of HDPE and PET was conducted through accelerated irradiation in an ultraviolet (UV) chamber. The ultraviolet?aged HDPE and PET was melt blended (in 80\\/20 wt. ratio) and rectangular slit die extruded, followed by hot stretch and quenching; thus the

2007-01-01

297

Finite strain behavior of poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate)-glycol (PETG)  

Microsoft Academic Search

Uniaxial and plane strain compression experiments are conducted on amorphous poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate)-glycol (PETG) over a wide range of temperatures (25–110°C) and strain rates (.005–1.0s?1). The stress–strain behavior of each material is presented and the results for the two materials are found to be remarkably similar over the investigated range of rates, temperatures, and strain levels. Below

Rebecca B. Dupaix; Mary C. Boyce

2005-01-01

298

Positronium formation in a polymer blend of polyethylene and chlorinated polyethylene  

NASA Astrophysics Data System (ADS)

We discuss positronium (Ps) formation in a polymer blend system consisting of low-density polyethylene (PE) and chlorinated polyethylene (CPE, random copolymer with a chlorine weight content of 35%). Positron lifetime measurements were performed as a function of CPE composition (0-100%), electric field (F=0-40 kV/cm), temperature (T=30-300 K), and positron irradiation time (t=0-110 h) at T=75 K, and room temperature. We note that Ps formation occurs by recombination of electron-positron pairs with both small (<~3 nm) and large (>~3 nm) initial separations. At low temperatures, pairs with large separations are formed not only in the positron spur (blob) but also as a result of coupling of a thermalized positron with one of the localized electrons produced by positron irradiation. For PE, the contribution of the latter process to Ps formation appears as a gradual increase in relative intensity of the long-lived ortho-positronium (o-Ps) component as a function of positron irradiation time. The addition of CPE appreciably reduces the contribution from pairs with large separations, and Ps formation in pure CPE occurs exclusively from pairs with small initial separations, much less influenced by external parameters such as the temperature and electric field.

Wang, C. L.; Kobayashi, Y.; Zheng, W.; Zhang, C.; Nagai, Y.; Hasegawa, M.

2001-02-01

299

Effectiveness of poly(ethylene terephthalate) and high-density polyethylene in protection of milk flavor.  

PubMed

The development of certain off-flavors in whole milk (3.25% milk fat) as related to packaging material [glass, high-density polyethylene (HDPE), amber poly(ethylene terephthalate) (PETE), clear PETE, and clear PETE-UV] were evaluated after exposure to fluorescent light (1100 to 1300 lx) for 18 d at 4 degrees C. Control samples packaged and stored under identical conditions were wrapped in foil to prevent light exposure. Selected flavor compounds in milk were measured analytically on d 0, 7, 14, and 18 of storage, while intensities of "oxidation," "acetaldehyde," and "lacks freshness" off-flavors were determined by sensory analysis at the same intervals. In light-exposed samples, oxidation off-flavor was significantly lower when packaged in amber PETE versus other containers. Milk packaged in HDPE containers showed a significantly higher level of oxidation off-flavor than milk packaged in PETE-UV containers but not higher than clear PETE or glass containers. No significant difference in acetaldehyde off-flavor was found between package material treatments (exposed or protected). Acetaldehyde concentration never exceeded flavor threshold levels, regardless of packaging material. Amber and PETE-UV materials proved to be a competitive packaging choice for milk in preserving fresh milk flavor. PMID:11417691

van Aardt, M; Duncan, S E; Marcy, J E; Long, T E; Hackney, C R

2001-06-01

300

Remote atmospheric-pressure plasma activation of the surfaces of polyethylene terephthalate and polyethylene naphthalate.  

PubMed

The surfaces of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) were treated with an atmospheric-pressure oxygen and helium plasma. Changes in the energy, adhesion, and chemical composition of the surfaces were determined by contact angle measurements, mechanical pull tests, and X-ray photoelectron spectroscopy (XPS). Surface-energy calculations revealed that after plasma treatment the polarity of PET and PEN increased 6 and 10 times, respectively. In addition, adhesive bond strengths were enhanced by up to 7 times. For PET and PEN, XPS revealed an 18-29% decrease in the area of the C 1s peak at 285 eV, which is attributable to the aromatic carbon atoms. The C 1s peak area due to ester carbon atoms increased by 11 and 24% for PET and PEN, respectively, while the C 1s peak area resulting from C-O species increased by about 5% for both polymers. These results indicate that oxygen atoms generated in the plasma rapidly oxidize the aromatic rings on the polymer chains. The Langmuir adsorption rate constants for oxidizing the polymer surfaces were 15.6 and 4.6 s(-1) for PET and PEN, respectively. PMID:18834154

Gonzalez, E; Barankin, M D; Guschl, P C; Hicks, R F

2008-11-01

301

Engineering Poly(ethylene glycol) Materials to Promote Cardiogenesis  

NASA Astrophysics Data System (ADS)

Heart failure is one of the leading causes of death worldwide, and the current costs of treatment put a significant economic burden on our societies. After an infarction, fibrotic tissue begins to form as part of the heart failure cascade. Current options to slow this process include a wide range of pharmaceutical agents, and ultimately the patient may require a heart transplant. Innovative treatment approaches are needed to bring down costs and improve quality of life. The possibility of regenerating or replacing damaged tissue with healthy cardiomyocytes is generating considerable excitement, but there are still many obstacles to overcome. First, while cell injections into the myocardium have demonstrated slight improvements in cardiac function, the actual engraftment of transplanted cells is very low. It is anticipated that improving engraftment will boost outcomes. Second, cellular differentiation and reprogramming protocols have not yet produced cells that are identical to adult cardiomyocytes, and immunogenicity continues to be a problem despite the advent of autologously derived induced pluripotent stem cells. This dissertation will explore biomaterials approaches to addressing these two obstacles. Tissue engineering scaffolds may improve cell engraftment by providing bioactive factors, preventing cell anoikis, and reducing cell washout by blood flow. Poly(ethylene glycol) (PEG) is often used as a coating to reduce implant rejection because it is highly resistant to protein adsorption. Because fibrosis of a material in contact with the myocardium could cause arrhythmias, PEG materials are highly relevant for cardiac tissue engineering applications. In Chapter 2, we describe a novel method for crosslinking PEG microspheres around cells to form a scaffold for tissue engineering. We then demonstrate that HL-1 cardiomyocyte viability and phenotype are retained throughout the fabrication process and during the first 7 weeks of culture. In the third chapter of the dissertation, we demonstrate that the use of PEG cell culture substrates can improve efficiency of direct reprogramming from fibroblasts to cardiomyocytes for cell transplantation. Standard tissue culture plastic adsorbs proteins from the cell media, increasing experimental variability via non-specific signaling. Because of its protein resistant properties, PEG provides cells with highly specific signals. In addition to improving the efficiency, we found that presentation of RGD peptides stimulated proliferation during reprogramming. Combined, the improvements enabled us to approximately double the number of cardiomyocytes produced by the protocol. In Chapter 4, we explore the effects of 3D culture on the direct reprogramming protocol described in Chapter 3. We demonstrate that the variables involved in 3D culture, including scaffold material, diffusion, cellular remodeling, and scaffold topography, have significant effects on reprogramming efficiency. This chapter provides the groundwork for future studies developing 3D microenvironments for efficient and scalable reprogramming to cardiomyocytes.

Smith, Amanda Walker

302

Delivery of sphingosine 1-phosphate from poly(ethylene glycol) hydrogels  

PubMed Central

While protein growth factors promote therapeutic angiogenesis, delivery of lipid factors such as sphingosine 1-phosphate (S1P) may provide better stabilization of newly formed vessels. We developed a biomaterial for the controlled delivery of S1P, a bioactive lipid released from activated platelets. Multi-arm poly(ethylene glycol)-vinyl sulfone was crosslinked with albumin, a lipid-transporting protein, to form hydrogels. The rate of S1P release from the materials followed Fickian kinetics and was dependent upon the presence of lipid carriers in the release solution. Delivery of S1P from RGD-modified hydrogels increased the cell migration speed of endothelial cells growing on the materials. The materials also induced angiogenesis in the chorioallantoic membrane assay. Our data demonstrate that the storage and release of lipid factors provides a new route for the induction of angiogenesis by artificial materials.

Wacker, Bradley K.; Scott, Evan A.; Kaneda, Megan M.; Alford, Shannon K.; Elbert, Donald L.

2008-01-01

303

Uterine bleeding in rhesus monkeys after insertion of polyethylene and copper containing polyethylene intrauterine contraceptive devices.  

PubMed

The effect of polyethylene devices, with or without copper, on the incidence of postinsertion bleeding episodes in rhesus monkeys is reported. 24 rhesus monkeys were divided into 4 groups. Group 1 was fitted with the Lippes loop (No. 25). Group 2 was fitted with the loop with 2 cm copper wire (.2 mm diam.) wound around it. Group 3 was fitted with plain polyethylene T-device without copper, and Group 4 was fitted with copper-T (model TCu-200 L). Vaginal smears of all of the monkeys were examined every 12 hours for microscopic bleeding. 1 of the animals of each group showing frank uterine bleeding was sacrificed. The uterus was dissected out and processed for histological studies. The results showed that the incidence of postinsertion bleeding in rhesus monkeys varied according to the design and material of the devices. The severity of bleeding was markedly less with either the plain T-device or the T-device with copper, as compared to Lippes loop with or without this metal. The copper containing Lippes loop caused less bleeding in so far as duration and flow were concerned than the loop without copper. The severity of bleeding in animals fitted with plain T-device was less than that seen after insertion of the plain Lippes loop. This suggests that the design of the device is a crucial factor in bleeding. A comparison between plain T-devices and copper T-devices showed a beneficial action of copper in reducing the incidence of postinsertion bleeding. PMID:4205756

Chandra, H; Kar, A B; Dasgupta, P R

1973-05-01

304

Comparison of alumina-polyethylene and metal-polyethylene in clinical trials.  

PubMed

The dimensional changes of hip sockets of Müller-type total endoprostheses is the subject of this article. Regular anteroposterior roentgenographs of the pelvis were taken to determine the orientation of the center of the prosthetic head in relation to the wire marker of the polyethylene cup. Three different materials used for the femoral balls and matched with polyethylene as socket material were investigated, and the results of the displacement of the ball into the socket were compared. Both creep and wear contribute to the dimensional changes of the hip sockets; the proportional amount of each mechanism is not known. Data from laboratory examinations suggest a relatively high rate of creep in the first six months after implantation. With longer periods, the dimensional changes are predominately caused by wear. In the beginning of joint function, measurements show a high rate of the yearly dimensional changes. The head shifts up to 0.5 mm per year and diminishes after five years to rates of 0.1-0.2 mm, respectively. All dimensional changes that exceed a shift of the head of 0.2 mm per year are considered to be unfavorable and to contribute to loosening of the implants. Using metallic balls (Protasul-2), 64% had a wear rate of less than 0.2 mm; of those using Prostasul-10, 77% had lower rates than 0.2 mm. In patients where ceramic balls were implanted, the displacement rate was below 0.2 mm per year in 95%. Therefore, ceramic seems to be the most favorable material. PMID:1516333

Zichner, L P; Willert, H G

1992-09-01

305

Friction and wear of hydroxyapatite reinforced high density polyethylene against the stainless steel counterface.  

PubMed

Hydroxyapatite (HA) reinforced high density polyethylene (HDPE) was invented as a biomaterial for skeletal applications. In this investigation, tribological properties (e.g. wear rate and coefficient of friction) of unfilled HDPE and HA/HDPE composites were evaluated against the duplex stainless steel in dry and lubricated conditions, with distilled water or aqueous solutions of proteins (egg albumen or glucose) being lubricants. Wear tests were conducted in a custom-built test rig for HDPE and HA/HDPE containing up to 40 vol % of HA. It was found that HA/HDPE composites had lower coefficients of friction than unfilled HDPE under certain conditions. HA/HDPE also exhibited less severe fatigue failure marks than HDPE. The degradation and fatigue failure of HDPE due to the presence of proteins were severe for low speed wear testing (100 rpm) as compared to high speed wear testing (200 rpm). This was due possibly to the high shear rate at the contact which could remove any degraded film instantaneously at high sliding speed, while with a low sliding speed the build-up of a degraded layer of protein could occur. The degraded protein layer would stay at the contact for a longer time and mechanical activation would induce adverse reactions, weakening the surface layer of HDPE. Both egg albumen and glucose were found to be corrosive to steel and adversely reactive for HDPE and HA/HDPE composites. The wear modes observed were similar to that of ultra-high molecular weight polyethylene. Specimens tested with egg albumen also displayed higher wear rates, which was again attributed to corrosion accelerated wear. PMID:15348592

Wang, M; Chandrasekaran, M; Bonfield, W

2002-06-01

306

75 FR 14569 - Polyethylene Retail Carrier Bags from Taiwan: Final Determination of Sales at Less Than Fair Value  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-583-843] Polyethylene Retail Carrier Bags from Taiwan: Final...Department) has determined that imports of polyethylene retail carrier bags (PRCBs) from...investigation of PRCBs from Taiwan. See Polyethylene Retail Carrier Bags From Taiwan:...

2010-03-26

307

78 FR 69817 - Polyethylene Retail Carrier Bags From Thailand: Final Court Decision and Amended Final Results of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...weighted-average duty margin for polyethylene retail carrier bags (PRCBs) from...2\\ See Polyethylene Retail Carrier Bags from...

2013-11-21

308

76 FR 1135 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Final Results of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and...

2011-01-07

309

75 FR 70901 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Final Results of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping order on polyethylene terephthalate film, sheet and strip...the Republic of Korea (Korea). See Polyethylene Terephthalate Film, Sheet, and...

2010-11-19

310

78 FR 72628 - Polyethylene Retail Carrier Bags From Thailand: Notice of Court Decision Not in Harmony With...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-549-821] Polyethylene Retail Carrier Bags From Thailand...review of the antidumping duty order on polyethylene retail carrier bags (PRCBs) from...Co., Ltd., v. United States, Polyethylene Retail Carrier Bag Committee,...

2013-12-03

311

78 FR 52500 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Notice of...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...2\\ See Polyethylene Terephthalate Film, Sheet, and Strip...Int'l Trade 2013); Polyethylene Terephthalate Film, Sheet, and...

2013-08-23

312

Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles were obtained by a facile protocol and thoroughly characterized. Superparamagnetic iron oxide nanoparticles synthesized using a modified forced hydrolysis method were functionalized with polyethylene glycol silane (PEG silane), precipitated and dried. These functionalized particles are dispersable in a range of solvents and concentrations depending on the desired properties. Examples of tunable properties are magnetic behavior, optical and magneto-optical response, thermal features and rheological behavior. As such, PEG silane functionalized particles represent a platform for the development of new materials that have broad applicability in e.g. biomedical, industrial or photonic environments. Magnetic, optical, magneto-optical, thermal and rheological properties of several ferrofluids based on PEG coated particles with different concentrations of particles dispersed in low molecular mass polyethylene glycol were investigated, establishing the applicability of such materials.

Brullot, W.; Reddy, N. K.; Wouters, J.; Valev, V. K.; Goderis, B.; Vermant, J.; Verbiest, T.

2012-06-01

313

Radiation Transport Properties of Polyethylene-Fiber Composites  

NASA Technical Reports Server (NTRS)

Composite materials that can both serve as effective shielding materials against cosmic-ray and energetic solar particles in deep space as well as structural materials for habitat and spacecraft remain a critical and mission enabling piece in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density coupled with high hydrogen content. Polyethylene fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of Polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at NASA's Marshall Space Flight Center and tested against 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

Kaul, Raj K.; Barghouty, A. F.; Dahche, H. M.

2003-01-01

314

Space radiation transport properties of polyethylene-based composites  

NASA Technical Reports Server (NTRS)

Composite materials that can serve as both effective shielding materials against cosmic-ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene-fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

Kaul, R. K.; Barghouty, A. F.; Dahche, H. M.

2004-01-01

315

[In-vivo wear of the slide combinations ceramics-polyethylene as opposed to metal-polyethylene].  

PubMed

The present study deals with long-term dimensional changes in cemented Müller-type total hip endoprostheses. Creep and wear contribute to different extents to the dimensional changes in polyethylene. The total amount of polyethylene wear is represented by the displacement of the femoral head into the socket. Within the first postoperative years, the head shifts up to a relatively high rate of about 0.5 mm per year. This rate diminishes after 5 years to an average of about 0.1 mm (ceramics) and 0.2 mm (metal) per year. Values exceeding 0.2 mm per year for the shift of the femoral head are considered to be unfavourable with regard to a probable loosening of the prosthesis. In this study we determined the orientation of the centre of the prosthetic head in relation to the wire marker of the polyethylene cup, comprising in all 369 total hip prostheses. After an average of 77 months, 96% of the prostheses with ceramic heads (n = 109) had a wear rate of less than 0.2 mm per year. Using metal heads (Protasul-2 and Protasul-10) this rate could only be measured in 71% (n = 109) of the prostheses (61.5 months). The combination ceramics-polyethylene produces half of the total amount of wear produced by metal-polyethylene. Younger patients should preferably be treated with a ceramic ballhead. PMID:9157352

Zichner, L; Lindenfeld, T

1997-02-01

316

78 FR 42105 - Polyethylene Terephthalate Film, Sheet, and Strip From India and Taiwan; Notice of Commission...  

Federal Register 2010, 2011, 2012, 2013

...701-TA-415 and 731-TA-933-934 (Second Review)] Polyethylene Terephthalate Film, Sheet, and Strip From India and Taiwan...determine whether revocation of the countervailing duty order on polyethylene terephthalate film, sheet, and strip (``PET''...

2013-07-15

317

77 FR 31833 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Notice of Rescission of...  

Federal Register 2010, 2011, 2012, 2013

...COMMERCE International Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Notice...an administrative review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip (PET Film)...

2012-05-30

318

Low-Temperature Tensile Properties of Polyethylene Terephthalate Multifiber Yarn and Polystyrene Foam.  

National Technical Information Service (NTIS)

The low temperature tensile properties of polyethylene terephthalate multifiber yarn and polystyrene foam, manufactured by a new process, were determined. The polyethylene terephthalate multifiber yarn was limited to 220 denier size. Two different foam de...

R. P. Reed R. L. Durcholz J. M. Arvidson

1971-01-01

319

76 FR 18156 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip From India: Extension...review under the countervailing duty order on polyethylene terephthalate film, sheet and strip from India...

2011-04-01

320

76 FR 39855 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, in Part, of...  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission...review of the countervailing duty order on polyethylene terephthalate film, sheet and strip from India...

2011-07-07

321

77 FR 76456 - Polyethylene Terephthalate Film, Sheet and Strip from Taiwan: Partial Rescission of the...  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet and Strip from Taiwan: Partial...review of the antidumping duty (AD) order on polyethylene terephthalate film, sheet and strip from Taiwan...

2012-12-28

322

75 FR 81570 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...See Polyethylene Terephthalate Film, Sheet and Strip from India...Polyethylene Terephthalate Film, Sheet and Strip from India...prior to the signing of the instant notice). Scope of the Order...pretreated, or primed PET film, whether extruded or...

2010-12-28

323

75 FR 49893 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...  

Federal Register 2010, 2011, 2012, 2013

...Polyethylene Terephthalate Film, Sheet, and Strip From the...on polyethylene terephthalate film, sheet, and strip (``PET...in a single country. In the instant review, the Department identified...to subject merchandise, PET film.\\18\\ On June 18,...

2010-08-16

324

Poly(ethylene glycol) fluorescent linkers.  

PubMed

The first examples of PEG linkers containing the highly fluorescent dansyl group have been synthesized. Quantum yields of these PEG fluorescent linkers (PFL) were determined and utilized in calculating the PEG number of various protein conjugates. The method was also shown to be applicable to lower molecular weight drugs as exemplified by taxol. PMID:8974459

Pendri, A; Martinez, A; Xia, J; Shorr, R G; Greenwald, R B

1995-01-01

325

75 FR 38978 - Polyethylene Retail Carrier Bags From the People's Republic of China, Malaysia, and Thailand...  

Federal Register 2010, 2011, 2012, 2013

...A-570-886, A-557-813, A-549-821] Polyethylene Retail Carrier Bags From the People's...revocation of the antidumping duty orders on polyethylene retail carrier bags (PRCBs) from...31412 (July 1, 2009); see also Polyethylene Retail Carrier Bags From China,...

2010-07-07

326

Action of polyethylene glycols with linear structure and different molecular weights on rat liver lysosomes  

Microsoft Academic Search

The action of nonpolar detergents — polyethylene glycols with linear structure and differing in molecular weight from 700 to 15,000 — on rat liver lysosomes was studied. Triton X-100 was found to activate acid phosphatase of the total lysosome fraction more than the other polyethylene glycols. The action of polyethylene glycols on activation of acid phosphatase in lysosomal subfractions was

A. V. Tret'yakov; E. M. Ryazanov; A. S. Tarkov; N. K. Asinovskaya; V. A. Filov

1975-01-01

327

21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Polyethylene glycol (mean molecular weight 200-9,500). 178.3750...178.3750 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene...ethylene oxide and water with a mean molecular weight of 200 to 9,500....

2010-01-01

328

21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).  

Code of Federal Regulations, 2010 CFR

... false Polyethylene glycol (mean molecular weight 200-9,500). 178.3750...178.3750 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene...ethylene oxide and water with a mean molecular weight of 200 to 9,500....

2009-04-01

329

Small intestinal permeability to mannitol, lactulose, and polyethylene glycol 400 in celiac disease  

Microsoft Academic Search

Mannitol (molecular weight 182), lactulose (342), and polyethylene glycol 400 (range 242–550) absorption was studied in 25 controls, 22 untreated celiacs, and 13 treated celiacs. Untreated celiacs absorbed less mannitol and more lactulose than controls. Absorption of higher as well as lower molecular-weight polyethylene glycols was reduced in untreated celiac disease. Absorption returned towards normal on treatment. Polyethylene glycol and

S. O. Ukabam; B. T. Cooper

1984-01-01

330

Surface charge and adsorption properties of polyethylene in aqueous solutions of inorganic electrolytes  

Microsoft Academic Search

Summary The streaming potentials of several sorts of polyethylene were determined as a function of pH and composition of aqueous solutions and the electrokinetic (zeta) potentials were calculated. The results were compared with the electrokinetic properties of glass and polystyrene. It has been found that H+ and OH- ions are potential-determining on polyethylene. The surface of polyethylene is charged negatively

P. Beneš; M. Paulenová

1973-01-01

331

Hydrophilic polysulfone film prepared from polyethylene glycol monomethylether via coupling graft  

NASA Astrophysics Data System (ADS)

In the presence of acid-acceptor Na2CO3, the nucleophilic substitution between chloromethylated polysulfone (CMPSF) and polyethylene glycol monomethylether (PEGME) was conducted. Polyethylene glycol (PEG) was coupling-grafted onto the side chains of polysulfone (PSF) so that the graft copolymer PSF-g-PEG was prepared and the hydrophilic modification of polysulfone membrane material was realized. The chemical structure of PSF-g-PEG was characterized by FTIR and 1H NMR. The influence of the main factors on the coupling graft reaction was investigated. The water static contact angle of PSF-g-PEG membrane was determined and its property of resisting protein pollution was examined by using bovine serum albumin (BSA) as a model protein. The experimental results show that the coupling graft reaction between CMPSF and PEGME can proceed successfully, and the reaction of chloromethyl groups of CMPSF with the hydroxyl end groups of PEGME is a typical SN1 nucleophilic substitution reaction. The polarity of the solvents and the reaction temperature greatly influence the reaction. The suitable solvent is dimethyl acetamide with stronger polarity and 70 °C is a suitable reaction temperature. After reaction of 36 h, the grafting degree of PEG can reach 48 g/100 g and the product yield is about 73.6%. The contact angle of PSF-g-PEG membrane declines rapidly with the increase of PEG grafting degree, displaying the obvious enhancement of the hydrophilicity. The adsorption capacity of BSA on PSF-g-PEG membrane decreases remarkably with the increase of PEG grafting degree, showing excellent antifouling ability of PSF-g-PEG membrane for proteins.

Du, Ruikui; Gao, Baojiao; Li, Yanbin

2013-06-01

332

Complement activation on poly(ethylene oxide)-like RFGD-deposited surfaces  

PubMed Central

Non-specific protein adsorption, particularly fibrinogen (Fg), is thought to be an initiating step in the foreign body response (FBR) to biomaterials by promoting phagocyte attachment. In previous studies, we therefore prepared radio frequency glow discharge (RFGD) polyethylene oxide (PEO)-like tetraglyme coatings (CH3O(CH2CH2O)4CH3) adsorbing less than 10 ng/cm2 Fg and showed that they had the expected low monocyte adhesion in vitro. However, when these were implanted in vivo, many adherent inflammatory cells and a fibrous capsule were found, suggesting the role of alternative proteins, such as activated complement proteins, in the FBR to these materials. We therefore investigated complement interactions with the tetraglyme surfaces. First, because of its well known role in complement C3 activation, we measured the hydroxyl group (-OH) content of tetraglyme, but found it to be very low. Second, we measured C3 adsorption to tetraglyme from plasma. Low amounts of C3 adsorbed on tetraglyme, though it displayed higher binding strength than the control surfaces. Finally, complement activation was determined by measuring C3a and SC5b-9 levels in serum after incubating with tetraglyme, as well as other surfaces that served as positive and negative controls, namely poly(vinyl alcohol) hydrogels, Silastic sheeting, and poly(ethylene glycol) self-assembled monolayers with different end groups. Despite displaying low hydroxyl group concentration, relatively high C3a and SC5b-9 levels were found in serum exposed to tetraglyme, similar to the values due to our positive control, PVA. Our results support the conclusion that complement activation by tetraglyme is a possible mechanism involved in the FBR to these biomaterials.

Szott, Luisa Mayorga; Stein, M. Jeanette; Ratner, Buddy D.; Horbett, Thomas A.

2010-01-01

333

Performance of Corrugated Pipe Manufactured with Recycled Polyethylene Content.  

National Technical Information Service (NTIS)

The corrugated drainage pipe market in the United States consumes in excess of a billion Pounds of virgin High-Density Polyethylene (HDPE) annually. At the same time, millions of pounds of recyclable HDPE are generated each year. Industry-funded research ...

D. Cuttino R. W. Thomas

2011-01-01

334

Charge distribution in polyethylene\\/ethylene vinylacetate laminates and blends  

Microsoft Academic Search

The formation of space charge in polyethylene\\/ethylene vinylacetate copolymer (PE\\/EVA) laminates was investigated using a pulsed electroacoustic (PEA) method. The formation of heterocharge was observed in PE while positive charge (holes) was distributed over the EVA specimen. In the laminates, however, a large amount of charge accumulates at the interface between PE and EVA, resulting in an increase of the

Kwang S. Suh; Jae Young Kim; Chang Ryong Lee; Tatsuo Takada

1996-01-01

335

Decay of electric charge on corona charged polyethylene  

Microsoft Academic Search

This paper describes a study on the surface potential decay of corona charged low density polyethylene (LDPE) films. A conventional corona charging process is used to deposit charge on the surface of film and surface potential is measured by a compact JCI 140 static monitor. The results from corona charged multilayer sample reveal that the bulk process dominates charge decay.

Zhiqiang Xu; Linwen Zhang; George Chen

2007-01-01

336

Mesophases in polyethylene, polypropylene, and poly(1-butene)  

Microsoft Academic Search

This paper contains new views about the amorphous and partially ordered phases of the three polymers listed in the title. The discussion is based on information on structure, thermodynamic stability, and large-amplitude molecular motion. Polyethylene is the basic backbone of all alkene polymers, and the other two are the first members of the vinyl polymers which have stereospecifically placed alkyl

Rene J Androsch; Maria Laura Di Lorenzo; Christoph Schick; Bernhard Wunderlich

2010-01-01

337

Acceleration of polyethylene foils by laser driven ablation  

Microsoft Academic Search

The production of thermonuclear energy, by laser driven implosion of spherical DT shells, with achievable laser technology, requires the development of an efficient and stable implosion. Certain aspects of the acceleration of the spherical shells can be studied experimentally by irradiating thin, 5 to 25 mu m, polyethylene foils. The results of foil acceleration experiments performed using a Nd:YAG-Glass laser

H. G. Amlstrom; G. A. Burginyon; R. A. Haas

1974-01-01

338

Blends of Liquid Crystalline Polyesters and Polyethylene Terephthalate - Morphological Studies  

Microsoft Academic Search

Polyethylene terephthalate (PET) was blended with two different kinds of liquid crystalline (LC) polyesters with the level of LC polyester varying from 5 to 15 weight %. Homogeneous samples were prepared by melt blending the polymers in twin screw extruder. The crystallization and morphology of these blends was studied with the help of differential scanning calorimetry (DSC), small angle light

S. K. Sharma; A. Tendolkar; A. Misra

1988-01-01

339

Influence of polystyrene and polyethylene packaging materials on food quality  

Microsoft Academic Search

Polystyrene (PS) and polyethylene (PE) used for packaging of food were studied on their effect on product quality. Different types of PS were tested: General purpose polystyrene (GPPS), high impact polystyrene (HIPS, which contains a dispersed rubber phase) and several blends of these types. PS contains detectable amounts of residual monomer, which has an unpleasant odour and\\/or taste. When the

J. P. H. Linssen

1992-01-01

340

Electroluminescence in Polyethylene Terephthalate (PET). II. AC Voltage  

Microsoft Academic Search

Electroluminescence in polyethylene terephthalate (PET) was observed under AC voltages. The electroluminescence was found to be controlled by the injection of electrons from the Al electrode, together with the space charge accumulation. The occurrence of the injection and accumulation of electrons was demonstrated by thermally-stimulated current analysis. The significant modification of the internal field by the space charge resulted in

Kenzo Kojima; Yoshiaki Takai; Masayuki Ieda

1983-01-01

341

Migration from polyethylene terephthalate under all conditions of use  

Microsoft Academic Search

The condition of time and temperature under which PET (polyethylene terephthalate) is used in food contact applications is reviewed. The effect upon overall migration into fat simulants of varying temperature, time, thickness and crystallinity of the PET is discussed, with experimental data. Specific migration of monomers, catalyst residues, colourants and acetaldehyde from PET into food simulants is reported.

R. Ashby

1988-01-01

342

Infrared studies of chain folding in polymers. II. Polyethylene terephthalate  

Microsoft Academic Search

An infrared method has been developed for analyzing the spectra of a semicrystalline polymer for bands arising from the folded chain. The basis of the assignment is the contrasting behavior of crystalline and fold bands during annealing and degradation. The method has been applied to polyethylene terephthalate (PET), and as a result the 988-cm- band has been assigned to a

J. L. Koenig; M. J. Hannon

1967-01-01

343

Infrared spectra of high polymers Part IX. Polyethylene terephthalate  

Microsoft Academic Search

Infrared spectra of polyethylene terephthalate and three of its deuterated analogs have been obtained in the region of 70 to 3600 cm-1, polarized spectra having been obtained down to 330 cm-1. On the basis of analysis of the predicted spectrum, and with the aid of data from benzene and substituted benzenes, a complete assignment of the spectrum has been made.

C. Y. Liang; S. Krimm

1959-01-01

344

FUEL ELEMENTS OF URANIUM OXIDE-POLYETHYLENE DISPERSIONS  

Microsoft Academic Search

The German Siemens training reactor SUR-100 has a core of UâO\\/sub ; 8\\/ embedded in a dispersion in polyethylene as moderator. The design and ; construction of the fuel elements are described. The core consists of several ; circular plates 24-cm in diameter that are stacked to form a cylinder about 26 cm ; high. The proportion of UâOâ and

Hein

1962-01-01

345

Transient processes at the nanofilled polyethylene-metal contact interface  

NASA Astrophysics Data System (ADS)

The dependences of the dielectric constant of composites based on low-density polyethylene and transition metal oxide nanoparticles dispersed in the volume of this matrix on the temperature and the time of equilibration of the concentration of carriers in a near-surface contact region have been studied under conditions that prevent carrier injection processes at the metal-nanocomposite interface.

Ul'zutuev, A. N.; Ushakov, N. M.

2012-07-01

346

Properties of crosslinked ultra-high-molecular-weight polyethylene  

Microsoft Academic Search

Substantially reducing the rate of generation of wear particles at the surfaces of ultra-high-molecular-weight polyethylene (UHMWPE) orthopedic implant bearing components, in vivo, is widely regarded as one of the most formidable challenges in modern arthroplasty. In the light of this, much research attention has been paid to the myriad of endogenous and exogenous factors that have been postulated to affect

Gladius Lewis

2001-01-01

347

A process for solidifying sodium nitrate waste in polyethylene  

SciTech Connect

A laboratory-scale process has been developed for the solidification of nitrate salt wastes in polyethylene. The process uses a commercially available single-screw extruder which continuously discharges prescribed polyethylene-waste mixtures from the hoppers to the output die, where it is extruded into a container while still in the molten form. The molten mixture (/approximately/110--120/degree/C) conforms to the shape of the container and solidifies upon cooling. Proportional feeders maintain waste to binder ratio and homogeneity of the waste form. Present studies use dry wastes, although wet solid wastes can be processed using vented extrudes of the type used for the bitumen solidification process. Tests were performed to determine leachability and mechanical stability. Emphasis is placed upon leaching of nitrates from the waste forms. Differential Scanning Calorimetry (DSC) was used to confirm the compatibility of polyethylene and simulated salt wastes at elevated temperatures. Components of the polyethylene/NaNO/sub 3/ system, alone and in combination, were tested by DSC at temperatures to 400/degree/C. 14 refs., 6 figs.

Heiser, J.H. III; Franz, E.M.; Colombo, P.

1987-04-01

348

Long-term performance of cables based on chlorosulphonated polyethylene  

Microsoft Academic Search

Cables based on chlorosulphonated polyethylene were aged at different temperatures between 120 and 200 °C and their conditions were assessed by mechanical methods: micro-indenter and tensile testing. Some of the cables were not aged prior to the oven ageing whereas other cables had been exposed to almost 25 years of service at controlled temperatures (30–54 °C) and atmospheres (nitrogen and

M. J. Sandelin; U. W. Gedde

2004-01-01

349

21 CFR 177.1600 - Polyethylene resins, carboxyl modified.  

Code of Federal Regulations, 2013 CFR

... INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic...polyethylene resins consist of basic polymers produced when ethylene-methyl...more than 25 weight percent of polymer units derived from methyl...food-contact articles, a separate test sample is to be used for...

2013-04-01

350

Laser irradiation effects on polyethylene sheets containing carbon nanotubes  

NASA Astrophysics Data System (ADS)

Ultra high molecular weight polyethylene was chemically mixed with multiwall carbon nanotubes (CNT) and irradiated with pulsed visible laser (532 nm wavelength, 170 mJ pulse energy, 10 Hz repetition rate) for different times. Physical and mechanical characterization analyses were performed before and after the laser irradiation. CNT presence increases the polymeric hardness and the surface wet ability. Laser irradiation modifies a thin surface layer, of the order of 100-200 ?m depth. Absorption coefficient in CNTs (˜2×104 cm-1) is higher compared with that of polyethylene (˜150 cm-1) and absorbed energy generates fusion and removing of nanotubes. The final nanocomposite surface properties changes becoming similar to that of pure polyethylene, while the bulk properties remain unchanged. Generally, laser irradiation changes the nanocomposite wet ability, decreases its hardness, increasing its roughness. At low irradiation doses nanotubes are broken and detached from surface inducing voids and discontinuities. At high doses the surface appears more and more compact and rich in polyethylene.

Visco, A. M.; Campo, N.; Beltrano, J. J.; Torrisi, L.

351

SECURING CONTAINERIZED HAZARDOUS WASTES WITH WELDED POLYETHYLENE ENCAPSULATES  

EPA Science Inventory

Full-scale encapsulation of 208-liter (55-gal) drums was studied as a means for managing corroding containers of hazardous wastes in the field and rendering them suitable for transport and safe deposit within a final disposal site such as a landfill. Polyethylene (PE) receivers w...

352

Neutron production from polyethylene and common spacecraft materials  

Microsoft Academic Search

We report experimental measurements of neutron production from collisions of neutron beams with polyethylene blocks simulating tissue at the Los Alamos National Laboratory Neutron Science Center and 1 GeV\\/amu iron nuclei with spacecraft shielding materials at the Brookhaven National Laboratory AGS

Richard H. Maurer; David R. Roth; James D. Kinnison; Thomas M. Jordan; Lawrence H. Heilbronn; Jack Miller; Cary J. Zeitlin

2001-01-01

353

Simple EOS for linear (high-density) polyethylene (Marlex)  

SciTech Connect

A simple equation of state (EOS) for linear (high-density) polyethylene (Marlex) was generated and added to the T-4 Sesame EOS Library as material number 7180. This new EOS for Marlex reproduces the experimental shock Hugoniot data for the initial state density rho/sub 0/ = 0.954 g/cm/sup 3/ or Mg/m/sup 3/.

Dowell, F

1982-11-01

354

Washing Exposure Trails of Polyethylene and Poly (Vinyl Chloride).  

National Technical Information Service (NTIS)

Experiments were carried out to determine the effects, if any, of regular washing of exposed samples of polyethylene and PVC sheet. It was shown that washing, either by rain or regularly by hand over an eighteen month period does not wash away or leach ou...

M. P. Bladen E. J. Hill

1973-01-01

355

ADVANCED TWO LAYER POLYETHYLENE COATING TECHNOLOGY FOR PIPELINE PROTECTION  

Microsoft Academic Search

SUMMARY: Oil and Gas pipelines are protected by various types of external coatings in conjunction with CP systems. Polyethylene is commonly used as the top coat in two or three layer systems. The existing two layer system found in the North American and Australian markets uses an adhesive that is mastic-based. It provides excellent corrosion resistant properties and has relatively

S. Guan; P. Mayes; A. Andrenacci; D. Wong; Bredero Shaw

356

Ultraflexible, freestanding nanomembranes based on poly(ethylene glycol).  

PubMed

Extremely elastic and highly stable nanomembranes of variable thickness (5-350 nm) made completely of poly(ethylene glycol) are prepared by a simple procedure. The membranes exhibit distinct biorepulsive and hydrogel properties. They offer new possibilities for applications such as supports in transmission electron microscopy, matrices for inorganic nanoparticles, and pressure-sensitive elements for sensors. PMID:24677589

Meyerbröker, Nikolaus; Zharnikov, Michael

2014-05-28

357

Enhancement of biodegradability of disposable polyethylene in controlled biological soil  

Microsoft Academic Search

Plastics as polyethylene are widely used in packaging and other agricultural applications. They accumulate in the environment at a rate of 25 million tons per year. Thus, the development and use of degradable plastics was proposed as a solution for plastic waste problem. Because of the ever-increasing use of plastic films, nowadays, biodegradability has become a useful characteristic for plastics.

Yüksel Orhan; Hanife Büyükgüngör

2000-01-01

358

DUCTILE-TO-BRITTLE TRANSITION TIME IN POLYETHYLENE GEOMEMBRANE SHEET  

EPA Science Inventory

The susceptibility of polyethylene (PE) geomembranes to stress cracking was evaluated in the laboratory using an accelerated notched constant load testing (NCLT) method. he test specimens were subjected to various stress levels which ranged from 25% to 70% of the yield stress at ...

359

Soil Load Mobilization in Axially Loaded Buried Polyethylene Pipes  

Microsoft Academic Search

The performance evaluation of buried polyethylene (PE) pipelines in areas prone to ground movement is a key consideration in natural gas distribution systems. Considering the relatively smaller deformation stiffness and nonlinear stress-strain response of PE pipe material, understanding the basic pipe-soil interaction mechanisms both under small and large strain levels forms a critical part in these evaluations. In determining the

D. Wijewickreme; L. Weerasekara; G. Johnson

360

A lithium battery electrolyte based on gelled polyethylene oxide  

Microsoft Academic Search

Gel polymer electrolytes (GPEs) were prepared by dipping a polyethylene oxide (PEO)-based solid polymer electrolyte in lithium triflate\\/propylene carbonate (PC) liquid electrolyte solutions. The quantity of the liquid electrolyte gelled in the polymer was monitored as a function of dipping time in several liquid electrolytic solutions characterized by a different salt concentration. The GPE conductivity was measured as a function

Pier Paolo Prosini; Stefano Passerini

2002-01-01

361

High Density Polyethylene (HDPE) Clay Nanocomposite for Dielectric Applications  

Microsoft Academic Search

Indigenous Montmorillonite clay available from Kutchh region in western part of India was modified by Hexadecyl trimethyl ammonium bromide, a quaternary ammonium compound to make it organophilic. It was blended with high density polyethylene (HDPE) in a Brabender Plasticoder. The condition for blending was optimized and sheets were prepared for evaluating mechanical, electrical and thermal properties. Mechanical property such as

K. S. Shah; R. C. Jain; V. Shrinet; A. K. Singh; D. P. Bharambe

2009-01-01

362

TSD currents in thermally aged and ?-irradiated polyethylene terephthalate film  

Microsoft Academic Search

The influence of thermal aging and ?-irradiation on TSD (thermal stimulated depolarization) current spectra of polyethylene terephthalate (PET) film was studied. Dynamics of the complex aging as well as changes in activation-energy temperature distributions were determined. A comparison of the activation-energy distributions for fresh samples and those ?-irradiated with a dose of 15 Mrads and subsequently thermally aged shows that

S. M. Gubanski; A. Gubanski; B. Macalik

1988-01-01

363

Detecting protein analytes that modulate transmembrane movement of a polymer chain within a single protein pore  

Microsoft Academic Search

Here we describe a new type of biosensor element for detecting proteins in solution at nanomolar concentrations. We tethered a 3.4 kDa polyethylene glycol chain at a defined site within the lumen of the transmembrane protein pore formed by staphylococcal ?-hemolysin. The free end of the polymer was covalently attached to a biotin molecule. On incorporation of the modified pore

Liviu Movileanu; Stefan Howorka; Orit Braha; Hagan Bayley

2000-01-01

364

Attachment of human primary osteoblast cells to modified polyethylene surfaces.  

PubMed

Ultra-high-molecular-weight polyethylene (UHMWPE) has a long history of use in medical devices, primarily for articulating surfaces due to its inherent low surface energy which limits tissue integration. To widen the applications of UHMWPE, the surface energy can be increased. The increase in surface energy would improve the adsorption of proteins and attachment of cells to allow tissue integration, thereby allowing UHMWPE to potentially be used for a wider range of implants. The attachment and function of human primary osteoblast-like (HOB) cells to surfaces of UHMWPE with various levels of incorporated surface oxygen have been investigated. The surface modification of the UHMWPE was produced by exposure to a UV/ozone treatment. The resulting surface chemistry was studied using X-ray photoelectron spectroscopy (XPS), and the topography and surface structure were probed by atomic force microscopy (AFM) and scanning electron microscopy (SEM), which showed an increase in surface oxygen from 11 to 26 atom % with no significant change to the surface topography. The absolute root mean square roughness of both untreated and UV/ozone-treated surfaces was within 350-450 nm, and the water contact angles decreased with increasing oxygen incorporation, i.e., showing an increase in surface hydrophilicity. Cell attachment and functionality were assessed over a 21 day period for each cell-surface combination studied; these were performed using SEM and the alamarBlue assay to study cell attachment and proliferation and energy-dispersive X-ray (EDX) analysis to confirm extracellular mineral deposits, and total protein assay to examine the intra- and extracellular protein expressed by the cells. HOB cells cultured for 21 days on the modified UHMWPE surfaces with 19 and 26 atom % oxygen incorporated showed significantly higher cell densities compared to cells cultured on tissue culture polystyrene (TCPS) from day 3 onward. This indicated that the cells attached and proliferated more readily on the UV/ozone-treated UHMWPE surfaces than on untreated UHMWPE and TCPS surfaces. Contact guidance of the cells was observed on the UHMWPE surfaces by both SEM and AFM. Scanning electron micrographs showed that the cells were confluent on the modified UHMWPE surfaces by day 10, which led to visible layering of the cells by day 21, an indicator of nodule formation. In vitro mineralization of the extracellular matrix expressed by the HOB cells on the modified UHMWPE surfaces was confirmed by SEM and EDX analysis; spherulite structures were observed near cell protrusions by day 21. EDX analysis confirmed the spherulites to contain calcium and phosphorus, the major constituents in calcium phosphate apatite, the mineral phase of bone. Overall cell attachment, functionality, and mineralization were found to be enhanced on the UV/ozone-modified UHMWPE surfaces, demonstrating the importance of optimizing the surface chemistry for primary HOB cells. PMID:19275183

Poulsson, Alexandra H C; Mitchell, Stephen A; Davidson, Marcus R; Johnstone, Alan J; Emmison, Neil; Bradley, Robert H

2009-04-01

365

Tuning the superstructure of ultrahigh-molecular-weight polyethylene/low-molecular-weight polyethylene blend for artificial joint application.  

PubMed

An easy approach was reported to achieve high mechanical properties of ultrahigh-molecular-weight polyethylene (UHMWPE)-based polyethylene (PE) blend for artificial joint application without the sacrifice of the original excellent wear and fatigue behavior of UHMWPE. The PE blend with desirable fluidity was obtained by melt mixing UHMWPE and low molecular weight polyethylene (LMWPE), and then was processed by a modified injection molding technology-oscillatory shear injection molding (OSIM). Morphological observation of the OSIM PE blend showed LMWPE contained well-defined interlocking shish-kebab self-reinforced superstructure. Addition of a small amount of long chain polyethylene (2 wt %) to LMWPE greatly induced formation of rich shish-kebabs. The ultimate tensile strength considerably increased from 27.6 MPa for conventional compression molded UHMWPE up to 78.4 MPa for OSIM PE blend along the flow direction and up to 33.5 MPa in its transverse direction. The impact strength of OSIM PE blend was increased by 46% and 7% for OSIM PE blend in the direction parallel and vertical to the shear flow, respectively. Wear and fatigue resistance were comparable to conventional compression molded UHMWPE. The superb performance of the OSIM PE blend was originated from formation of rich interlocking shish-kebab superstructure while maintaining unique properties of UHMWPE. The present results suggested the OSIM PE blend has high potential for artificial joint application. PMID:22339721

Xu, Ling; Chen, Chen; Zhong, Gan-Ji; Lei, Jun; Xu, Jia-Zhuang; Hsiao, Benjamin S; Li, Zhong-Ming

2012-03-01

366

Infrared, Raman and INS studies of poly-ethylene oxide oligomers  

NASA Astrophysics Data System (ADS)

In the present paper the experimental findings obtained by different spectroscopic techniques on water mixtures of a protein model system, i.e. PolyEthylene Oxide (PEO), are reported. By increasing the polymerization degree m, the D-LAM spectral contribution shows a behavior of the centre frequency and of linewidth which tends to reach a constant value. Also the intramolecular OH stretching contribution, by increasing m, shows a shift which tends to flatten for polymers with molecular weight higher than Mw = 600. These results can be connected with the oligomer–polymer transition, at m = 13. When in aqueous solutions the D-LAM frequency increases towards the value corresponding to that of the crystal phase; similarly one observes also a sharpening of the D-LAM spectral contribution. These evidences suggest the presence of a more ordered conformation of PEO in water in respect to the melt phase.

Migliardo, F.; Magazù, S.; Caccamo, M. T.

2013-09-01

367

Plasma treated polyethylene grafted with adhesive molecules for enhanced adhesion and growth of fibroblasts.  

PubMed

The cell-material interface plays a crucial role in the interaction of cells with synthetic materials for biomedical use. The application of plasma for tailoring polymer surfaces is of abiding interest and holds a great promise in biomedicine. In this paper, we describe polyethylene (PE) surface tuning by Ar plasma irradiating and subsequent grafting of the chemically active PE surface with adhesive proteins or motives to support cell attachment. These simple modifications resulted in changed polymer surface hydrophilicity, roughness and morphology, which we thoroughly characterized. The effect of our modifications on adhesion and growth was tested in vitro using mouse embryonic fibroblasts (NIH 3T3 cell line). We demonstrate that the plasma treatment of PE had a positive effect on the adhesion, spreading, homogeneity of distribution and moderately on proliferation activity of NIH 3T3 cells. This effect was even more pronounced on PE coated with biomolecules. PMID:23827550

Rimpelová, Silvie; Kasálková, Nikola Slepi?ková; Slepi?ka, Petr; Lemerová, Helena; Švor?ík, Václav; Ruml, Tomáš

2013-04-01

368

DELIVERY OF THERAPEUTIC PROTEINS  

PubMed Central

The safety and efficacy of protein therapeutics are limited by three interrelated pharmaceutical issues, in vitro and in vivo instability, immunogenicity and shorter half-lives. Novel drug modifications for overcoming these issues are under investigation and include covalent attachment of poly(ethylene glycol) (PEG), polysialic acid, or glycolic acid, as well as developing new formulations containing nanoparticulate or colloidal systems (e.g. liposomes, polymeric microspheres, polymeric nanoparticles). Such strategies have the potential to develop as next generation protein therapeutics. This review includes a general discussion on these delivery approaches.

Pisal, Dipak S.; Kosloski, Matthew P.; Balu-Iyer, Sathy V.

2009-01-01

369

[Recombinant granulocyte-colony stimulating factor (filgrastim): optimization of conjugation with polyethylene glycol].  

PubMed

In order to create an active pharmaceutical substance of the drug with prolonged action the modification of recombinant human granulocyte colony-stimulating factor GCSF (filgrastim) with polyethylene glycol (PEG, M 21.5 kDa) was conducted. A method for preparation of PEG-filgrastim designed for the development and scaling-up of the technological process of production was described. Modification of proteins with PEG was performed by selective covalent attachment of the molecule alpha-methyl-PEG-propionaldehyde to the alpha-amino group of the N-terminal methionine amino acid residue of the recombinant GCSF. The conditions of the reaction, which provide the desired product yield at least 85% of the total protein, also high protein concentration in the reaction mixture (more than 9 mg/mL) and reduce consumption of PEG in terms of terminal alpha-amino group of the protein was chosen. The data of RP HPLC and MALDI-mass spectrometry showed that the produced drug modified by the N-terminal residue and contains no more than 10% of products with a high degree of modification. PMID:23342488

Puchkov, I A; Kononova, N V; Bobruskin, A I; Bairamashvili, D I; Mart'ianov, V A; Shuster, A M

2012-01-01

370

Cross Partition and Isoelectric Points of Proteins  

Microsoft Academic Search

AQUEOUS mixtures of dextran and polyethylene glycol give rise to liquid two-phase systems suitable for the partition of proteins1-5. The partition behaviour of proteins depends to a great extent on the ionic composition of the phase system and on the charge of the protein. Negatively charged materials, for example, have higher partition coefficients in sodium sulphate than in sodium chloride

Per-Åke Albertsson; SHIGERU SASAKAWA; HARRY WALTER

1970-01-01

371

Radiation resistance testing of high-density polyethylene. [Gamma rays  

SciTech Connect

Mechanical tests following gamma inrradiation and creep tests during irradiation have been conducted on high-density polyethylene (HDPE) to assess the adequacy of this material for use in high-integrity containers (HICs). These tests were motivated by experience in nuclear power plants in which polyethylene electrical insulation detoriorated more rapidly than expected due to radiation-induced oxidation. This suggested that HDPE HICs used for radwaste disposal might degrade more rapidly than would be expected in the absence of the radiation field. Two types of HDPE, a highly cross-linked rotationally molded material and a non-cross-linked blow molded material, were used in these tests. Gamma-ray irradiations were performed at several dose rates in environments of air, Barnwell and Hanford backfill soils, and ion-exchange resins. The results of tensile and bend testing on these materials following irradiation will be presented along with preliminary results on creep during irradiation.

Dougherty, D.R.; Adams, J.W.

1983-01-01

372

Polyethylene naphthalate as an excellent candidate for ripple nanopatterning  

NASA Astrophysics Data System (ADS)

The surface of polyethylene naphthalate (PEN) foils was exposed to KrF excimer laser treatment. Due to presence of condensed benzene rings has this polymer better mechanical, chemical and thermal properties in comparison to polyethylene terephthalate, which is widely applicable in electronic devices and also as tissue cell carriers. The influence of laser fluence and number of laser pulses on surface chemistry and morphology was determined. The surface morphology was studied with atomic force microscopy (AFM) in combination with scanning electron microscopy and focused ion beam (FIB-SEM). Surface wettability was characterized by the contact angle measurement. Surface chemistry was evaluated from XPS spectra. The optimal PEN process parameters with the most regular pattern were determined. The foils with optimal ripple pattern were consequently sputtered with gold nanolayers of 100 nm thickness. The parameters of ripple pattern after the metallization were introduced. It was found that the gold nanolayer is formed of electrically continuous wires, the ripple pattern was maintained.

Slepi?ka, P.; Ned?la, O.; Sajdl, P.; Kolská, Z.; Švor?ík, V.

2013-11-01

373

Acrylic acid grafting and collagen immobilization on poly(ethylene terephthalate) surfaces for adherence and growth of human bladder smooth muscle cells  

Microsoft Academic Search

In tissue engineering, degradable or non-degradable polymer matrices can act as cell-carrier-scaffolds. Cell adhesion and growth on these scaffolds can be promoted by immobilizing extracellular matrix proteins. Therefore, in this study, polymer poly(ethylene terephthalate) (PET) films were surface modified by graft polymerization of acrylic acid, to subsequently allow collagen (types I and III) immobilization and human smooth muscle cell expansion.

Isabelle Bisson; Marek Kosinski; Sylvie Ruault; Bhuvanesh Gupta; Jöns Hilborn; Florian Wurm; Peter Frey

2002-01-01

374

Toughening wood\\/polypropylene composites with polyethylene octene elastomer (POE)  

Microsoft Academic Search

Polyethylene octene elastomer (POE) as impact modifier was incorporated into wood\\/polypropylene composites (WPC) to enhance\\u000a the impact strength of the composite. Two extruding routes, i.e. direct extruding route and two-stage extruding route, were\\u000a adopted to produce Wood Powder\\/PP\\/POE ternary composites. The mechanical and dynamic mechanical analysis (DMA) properties\\u000a of the composites were investigated. The results showed that the addition of

Feng Jiang; Te-fu Qin

2006-01-01

375

Effect of Low Density Polyethylene on Polystyrene Foam  

Microsoft Academic Search

This work examines the foam density of polystyrene (PS) blended with low density polyethylene (LDPE) at various ratios, and the thermal conductivity of vacuum insulation panels (VIPs) using PS\\/PE with filler foam as core materials. The experimental results indicate that LDPE strongly influences the foam density of PS\\/PE foam and the content of open-cells in PS\\/PE with filler foam. A

Chang-Ming Wong; Shih-Jung Tsai; Chih-Hung Ying; Ming-Lang Hung

2006-01-01

376

Gasification of polyethylene using steam plasma generated by microwave discharge  

Microsoft Academic Search

Gasification of polyethylene (PE) pellet was studied using atmospheric argon-steam plasma generated by microwave discharge and the feasibility of the process was examined. The experimental results showed that additional steam to argon plasma promoted the weight decrease of PE and enhanced the production of H2, CO, CO2 and CH4. The results confirmed that the treatment of plastics with the steam

Hidetoshi Sekiguchi; Taichi Orimo

2004-01-01

377

The fracture process of ultra-high strength polyethylene fibres  

Microsoft Academic Search

The fracture behaviour of ultra-high strength polyethylene fibres has been investigated in dead load tests as well as by electron microscopical observation of the fracture surfaces. It was found that the fracture process in the fibres involves an activation energy of about 60 to 75 kJ mol-1, which implies that the strength is mainly determined by the lateral bond strength

Jan Smook; Wim Hamersma; Albert J. Pennings

1984-01-01

378

Elution behavior of polyethylene and polypropylene standards on carbon sorbents  

Microsoft Academic Search

The elution behavior of linear polyethylene and isotactic, atactic and syndiotactic polypropylene was tested using three different carbon column packings: porous graphite (Hypercarb), porous zirconium oxide covered with carbon (ZirChrom-CARB), and activated carbon TA 95. Several polar solvents with boiling points above 150°C were selected as mobile phases: 2-ethyl-1-hexanol, n-decanol, cyclohexylacetate, hexylacetate, cyclohexanone, ethylene glycol monobutyl ether and one non-polar

Rajesh Chitta; Tibor Macko; Robert Brüll; Grid Kalies

379

Polyethylene Structure as a Function of Temperature: An EDXD Investigation  

Microsoft Academic Search

Polyethylene structure has been investigated by energy dispersive X?ray diffraction (EDXD) as a function of temperature below the melting point, via Rietveld refinement. The behavior was studied at four temperatures, namely 25, 40, 70, and 88°C. In this range the structure undergoes a regular volume expansion that may be expressed in terms of specific volume ratio as VE\\/V25°C=0.991(2)+4.0(5)×10×T(°C). The variation

R. Caminiti; P. Ballirano; M. Carbone

2006-01-01

380

Cementation of a Polyethylene Liner Into a Metal Acetabular Shell  

Microsoft Academic Search

Cementation of a liner into a well-fixed acetabular shell is common in revision hip arthroplasty. We compare the biomechanical strengths of cemented liners with standard locked liners. Fifty polyethylene liners were inserted into acetabular shells using the standard locking mechanism or 1 of 2 cement types then loaded to failure by torsion or lever-out testing. Lever-out testing showed that all

Aaron A. Hofmann; Edward J. Prince; F. Thurston Drake; Kenneth J. Hunt

2009-01-01

381

CO 2 laser ablative etching of polyethylene terephthalate  

Microsoft Academic Search

Films of polyethylene terephthalate (PET) can be successfully etched with 9 µm radiation from a pulsed TEA CO2 laser. The relationship between etch depth and fluence is broadly similar to that observed for excimer laser etching but with a less well-defined threshold. Time-resolved photoacoustic measurements of stress waves generated in the interaction show that at a fluence of 1.8 J

P. E. Dyer; G. A. Oldershaw; J. Sidhu

1989-01-01

382

The Structural Dilemma of Bulk Polyethylene: An Intermediary Structure  

PubMed Central

Background The Fourier space (reciprocal space) image of bulk polyethylene consists of lines superimposed on the coherent diffuse background. The mixed character of the image indicates the complex nature of these compounds. The inability in detecting full images of reciprocal space of polymeric substances without Compton radiation and the other undesirable diffuse scatterings has misled the structural analysis (structural characterisation) of these materials. Principal Findings We propose the use of anomalous diffractometry where, it is possible to obtain a real image of reciprocal space without Compton radiation and other undesirable scatterings. By using classical diffractometry techniques this procedure is not possible. This methodology permitted us to obtain the “Direct Delta function”, in the case of polycrystalline substances that was not previously detected. A new procedure was proposed to interpret the image of reciprocal space of bulk polyethylene. The results show the predominance of the geometry of local order determination compared to the crystal unit cell. The analysis of x-ray diffraction images illustrates that the elementary structural unit is a tetrahedron. This structural unit illustrates the atoms in the network scatter in a coherent diffuse manner. Moreover, the interference function derived from the coherent diffuse scattering dampens out quickly and the degree of randomness is superior to a liquid state. The radial distribution function derived from this interference function shows bond shortening in the tetrahedron configuration. It is this particular effect, which stabilises polyethylene. Conclusion Here we show by anomalous diffractometry that the traditional concept of the two-phase or the crystal-defect model is an oversimplification of the complex reality. The exploitation of anomalous diffractometry has illustrated that polyethylene has an intermediate ordered structure.

Laridjani, Morteza; Leboucher, Pierre

2009-01-01

383

Surface characterization of polyethylene terephthalate\\/silica nanocomposites  

Microsoft Academic Search

Poly(ethylene terephthalate) (PET) based nanocomposites containing hydrophilic (i.e. Aerosil 200 or Aerosil TT 600) or hydrophobic (i.e. Aerosil R 972) nano-silica were prepared by melt compounding. Influence of nano-silica type on surface properties of the resultant nanocomposites was investigated by the use of Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), contact angle measurement (CAM), scanning electron microscopy (SEM)

Mazeyar Parvinzadeh; Siamak Moradian; Abosaeed Rashidi; Mohamad-Esmail Yazdanshenas

2010-01-01

384

Polyethylene and metal wear particles: characteristics and biological effects  

Microsoft Academic Search

This paper first presents a brief overview about the mechanism of wear particle formation as well as wear particle characteristics\\u000a in metal-on-polyethylene and metal-on-metal artificial hip joints. The biological effects of such particles are then described,\\u000a focusing on the inflammatory response induced by each type of particles as well as on how metal wear products may be the source\\u000a of

Isabelle Catelas; Markus A. Wimmer; Sandra Utzschneider

2011-01-01

385

Investigations of heavy ion tracks in polyethylene naphthalate films  

Microsoft Academic Search

The heavy ion beam (with fluence 3x108 ion\\/cm2) from a cyclotron has been used for irradiation of thin polyethylene naphthalate (PEN) films. Latent tracks in these polymeric films have been sensitized by UV radiation and then chemically etched in NaOH solution. The etching process parameters have been controlled by the electroconductivity method. After etching, parameters of samples have been examined

W. Starosta; D. Wawszczak; B. Sartowska; M. Buczkowski

1999-01-01

386

DBD treatment of polyethylene terephthalate: Atmospheric versus medium pressure treatment  

Microsoft Academic Search

In this paper, polyethylene terephthalate (PET) films are modified by a dielectric barrier discharge (DBD) in a helium\\/air mixture at medium (6.6 kPa) and atmospheric pressure. Surface analysis and characterization of the plasma-treated PET films is performed using contact angle measurements, X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The polymer films, modified with the DBD at medium and atmospheric

N. De Geyter; R. Morent; C. Leys; L. Gengembre; E. Payen; S. Van Vlierberghe; E. Schacht

2008-01-01

387

Hydrogen-hydrogen intermolecular structure of polyethylene in the melt  

Microsoft Academic Search

Three polyethylene samples, which differed in their degree of deuteration, were studied in neutron diffraction isotopic substitution (NDIS) experiments at 428 K. These results were complemented at small wavevectors by small angle neutron measurements. The intermolecular hydrogen-hydrogen (HH) structure function, hHH(Q), was obtained without recourse to intramolecular structure models, as demonstrated in a prior report. The PE experimental results are

J. D. Londono; B. K. Annis; A. Habenschuss; G. D. Smith; O. Borodin; C. Tso; E. T. Hsieh; A. K. Soper

1999-01-01

388

Surface treatment of polyethylene by fast atom beams  

Microsoft Academic Search

Ultra-high molecular-weight polyethylene (UHMWPE) was treated by fast atom beams (FAB) obtained from He, Ar, H2 and N2 with about 1 kV accelerating voltage and estimated fluence of 1017 particles cm?2. The modified surface layers were characterised by X-ray photoelectron spectroscopy (XPS or ESCA) and dynamic microhardness measurements. Each applied FAB treatment results in the increase of the bulk plasmon

T. Ujvári; A. Tóth; I. Bertóti; P. M. Nagy; A. Juhász

2001-01-01

389

Influence of antioxidants on polyethylene chemical crosslinking reaction  

Microsoft Academic Search

The influence of antioxidants on the chemical crosslinking of crosslinked polyethylene (XLPE) was investigated. Experiments were conducted using XLPE specimens crosslinked at various temperatures with added phenolic, sulfur-type and amine-type antioxidants. Specimens were characterized by measuring the gel fraction and the content of crosslinking byproducts, acetophenone, cumyl alcohol and ?-methyl styrene. It was found that sulfur-type antioxidant has the strongest

Yasuo Sekii; Yuichi Idei; Kiyotaka Asakawa

2001-01-01

390

Calorimetric study of polyethylene terephthalate)\\/poly(butylene terephthalate) blends  

Microsoft Academic Search

Poly(ethylene terephthalate)\\/poly(butylene terephthalate) blends [xPET\\/(l-x)PBT] were prepared by ultraquenching of the melt between two metal rolls rotating in a liquid nitrogen bath. Both DSC and WAXS studies indicate that immediately after preparation, the blends are amorphous regardless of the composition. Two glass transition temperatures are found for the as-quenched 0.5 PET\\/0.5 PBT blend. The activation energies determined from the dependence

I. Avramov; N. Avramova

1991-01-01

391

New active poly(ethylene glycol) derivative for amino coupling  

Microsoft Academic Search

The synthesis and characterization of an active poly(ethylene glycol) (PEG) derivative with new properties has been afforded starting from a side reaction of N-hydroxysuccinimide (NHS) in presence of N,N-dicyclohexylcarbodiimide (DCC). In particular, a ring opening of NHS in presence of DCC forms a ?-alanine active derivative, through Lossen rearrangement, which then reacts with PEG–NH2 yielding the active PEG derivative: PEG–NH–CO–?Ala–NH–CO–NHS.

G. Pasut; F. Caboi; R. Schrepfer; G. Tonon; O. Schiavon; F. M. Veronese

2007-01-01

392

Growth of ZnO nanowires on nonwoven polyethylene fibers  

Microsoft Academic Search

We report the growth of ZnO nanowires on nonwoven polyethylene fibers using a simple hydrothermal method at a temperature below the boiling point of water. The ZnO nanowires were grown from seed ZnO nanoparticles affixed onto the fibers. The seed ZnO nanoparticles, with diameters of about 6-7 nm, were synthesized in isopropanol by reducing zinc acetate hydrate with sodium hydroxide.

Sunandan Baruah; Chanchana Thanachayanont; Joydeep Dutta

2008-01-01

393

Crack initiation and viscoplasticity in polyethylene joint replacement components  

Microsoft Academic Search

\\u000a Ultrahigh molecular weight polyethylene (UHMWPE) is an abrasion resistant and bioinert polymer widely used as a bearing material\\u000a in total joint replacements. Recent reports of fracture and crack initiation in these systems make the prediction of crack\\u000a initiation a primary concern. Past work in assessing the resistance to crack propagation in UHMWPE has typically ignored the\\u000a creeping (quasi-static) constitutive contribution

Jevan Furmanski; P. Abhiram Sirimamilla; Clare M. Rimnac

394

Gas permeability measurement in polyethylene and its copolymer films  

Microsoft Academic Search

In this research, low density polyethylene (LDPE) and poly(ethylene-co-vinyl acetate) (EVA) were used as polymeric materials. The methods used to produce LDPE and EVA was film blowing and thermal-dry phase inversion. The amount of permeability, diffusivity and solubility of O2 and CO2 through above polymers were obtained and also the effect of temperature, pressure and film thickness for LDPE was

M. Gholizadeh; J. Razavi; S. A. Mousavi

2007-01-01

395

Ultraviolet reflective and mechanical properties of polyethylene mulching films  

Microsoft Academic Search

In order to assign the insect-repelling property to the mulching films for horticultural applications, low density polyethylene (LDPE) films were prepared by incorporating ultraviolet (UV) reflective additive (Tismo-D) in a melt-extruder. Not only their reflective characteristics but also their mechanical properties were investigated as a function of additive content. The comparison of optical properties between single and two layer films

Jae Whan Cho; Kyung Sik Woo; Byoung Chul Chun; Jong Shin Park

2001-01-01

396

Post-irradiation effects in polyethylenes irradiated under various atmospheres  

NASA Astrophysics Data System (ADS)

If a large amount of polymer free radicals remain trapped after irradiation of polymers, the post-irradiation effects may result in a significant alteration of physical properties during long-term shelf storage and use. In the case of polyethylenes (PEs) some failures are attributed to the post-irradiation oxidative degradation initiated by the reaction of residual free radicals (mainly trapped in crystal phase) with oxygen. Oxidation products such as carbonyl groups act as deep traps and introduce changes in carrier mobility and significant deterioration in the PEs electrical insulating properties. The post-irradiation behaviour of three different PEs, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) was studied; previously, the post-irradiation behaviour of the PEs was investigated after the irradiation in air (Suljovrujic, 2010). In this paper, in order to investigate the influence of different irradiation media on the post-irradiation behaviour, the samples were irradiated in air and nitrogen gas, to an absorbed dose of 300 kGy. The annealing treatment of irradiated PEs, which can substantially reduce the concentration of free radicals, is used in this study, too. Dielectric relaxation behaviour is related to the difference in the initial structure of PEs (such as branching, crystallinity etc.), to the changes induced by irradiation in different media and to the post-irradiation changes induced by storage of the samples in air. Electron spin resonance (ESR), differential scanning calorimetry (DSC), infra-red (IR) spectroscopy and gel measurements were used to determine the changes in the free radical concentration, crystal fraction, oxidation and degree of network formation, respectively.

Suljovrujic, E.

2013-08-01

397

Advances in polymer conjugation for the delivery of proteins and drugs  

Microsoft Academic Search

Several polymers have been explored for protein conjugation and poly(ethylene glycol) (PEG) emerged as the best candidate for protein modification (1). Many products, obtained by PEGylation of proteins, aptamers or liposomes are already in the market. Although being a successful technology, PEGylation still presents some limits, such as a decreased biological activity of conjugates with respect to the native proteins,

Gianfranco Pasut

398

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Boric acid (H3BO3), mixed esters with polyethylene...Chemical Substances § 721.1729 Boric acid (H3BO3), mixed esters with polyethylene...chemical substance identified as boric acid (H3 BO3 ), mixed...

2010-07-01

399

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Boric acid (H3BO3), mixed esters with polyethylene...Chemical Substances § 721.1729 Boric acid (H3BO3), mixed esters with polyethylene...chemical substance identified as boric acid (H3 BO3 ), mixed...

2009-07-01

400

Impact resistance and fractography in ultra high molecular weight polyethylenes.  

PubMed

Highly crosslinked ultra high molecular weight polyethylenes (UHMWPE) stabilized by a remelting process or by the addition of an antioxidant are highly wear resistant and chemically stable. However, these polyethylenes currently used in total joint replacements suffer a loss of mechanical properties, especially in terms of fracture toughness. In this study we analyze the impact behavior of different polyethylenes using an instrumented double notch Izod test. The materials studied are three resins: GUR1050, GUR1020 with 0.1wt% of vitamin E, and MG003 with 0.1wt% of vitamin E. These resins were gamma irradiated at 90kGy, and pre and post-irradiation remelting processes were applied to GUR1050 for two different time periods. Microstructural data were determined by means of differential scanning calorimetry and transmission electron microscopy. Fractography carried out on the impact fracture surfaces and images obtained by scanning electron microscopy after etching indicated the existence of a fringe structure formed by consecutive ductile-brittle and brittle-ductile transitions, which is related to the appearance of discontinuities in the load-deflection curves. A correlation has been made of the macroscopic impact strength results and the molecular chain and microstructural characteristics of these aforementioned materials, with a view to designing future resins with improved impact resistance. The use of UHMWPE resins with low molecular weight or the application of a remelting treatment could contribute to obtain a better impact strength behavior. PMID:24275347

Puértolas, J A; Pascual, F J; Martínez-Morlanes, M J

2014-02-01

401

Polyethylene macroencapsulation - mixed waste focus area. OST reference No. 30  

SciTech Connect

The lead waste inventory throughout the US Department of Energy (DOE) complex has been estimated between 17 million and 24 million kilograms. Decontamination of at least a portion of the lead is viable but at a substantial cost. Because of various problems with decontamination and its limited applicability and the lack of a treatment and disposal method, the current practice is indefinite storage, which is costly and often unacceptable to regulators. Macroencapsulation is an approved immobilization technology used to treat radioactively contaminated lead solids and mixed waste debris. (Mixed waste is waste materials containing both radioactive and hazardous components). DOE has funded development of a polyethylene extrusion macroencapsulation process at Brookhaven National Laboratory (BNL) that produces a durable, leach-resistant waste form. This innovative macroencapsulation technology uses commercially available single-crew extruders to melt, convey, and extrude molten polyethylene into a waste container in which mixed waste lead and debris are suspended or supported. After cooling to room temperature, the polyethylene forms a low-permeability barrier between the waste and the leaching media.

NONE

1998-02-01

402

Pseudotumor associated with metal-on-polyethylene total hip arthroplasty.  

PubMed

This case report details the presentation, imaging results, and operative findings of a pseudotumor associated with a press-fit metal-on-polyethylene total hip arthroplasty (THA). An 80-year-old man presented approximately 7 years after undergoing THA with worsening right groin and lateral hip pain with an associated proximal thigh mass. Physical examination demonstrated a tender, large anterolateral thigh mass that was also evident on metal artifact reduction sequence magnetic resonance imaging.An exploratory operative procedure revealed extensive tissue necrosis involving nearly the entire hip capsule, short external rotators, and tendinous portion of the gluteus medius muscle. In addition, marked surface corrosion was discovered about the taper at the head-neck junction of the prosthetic femoral component and the trunnion within the femoral head. The press-fit THA components were solidly fixed. The metallic head was replaced with a ceramic component, and the polyethylene liner was exchanged. The patient had complete resolution of his preoperative symptoms but had persistent problems with dislocations.Although reports of pseudotumor and local soft tissue reactions associated with metal-on-metal THAs have become increasingly ubiquitous in the literature, similar reports involving metal-on-polyethylene THA implants are less common. PMID:23672921

Scully, William F; Teeny, Steven M

2013-05-01

403

Stabilization of solid dispersions of nimodipine and polyethylene glycol 2000.  

PubMed

Previous investigations revealed that solid dispersions consisting of 20% (m/m) nimodipine and 80% (m/m) polyethylene glycol 2000 prepared by the melting method, represent supersaturated solid solutions of nimodipine recrystallizing upon storage at +25 degrees C. The objective of this study was the improvement of the storage stability by preventing recrystallization. The first approach in order to prevent recrystallization was the development of thermodynamically stable solid solutions by using solvents aiming to enhance the solubility of nimodipine in the carrier material. As potential solubility enhancing additives, polyethylene glycol 300, poly(ethylene/propylene glycol) copolymer, polypropylene glycol 1020, propylene glycol, glycerol and ethyl acetate were evaluated. The second approach enhancing storage stability was the addition of recrystallization inhibitors to supersaturated solid solutions, thereby delaying the transformation of the metastable supersaturated system to the thermodynamically stable state. Macrogol cetostearyl ether, macrogol glycerol monostearate, polysorbate 60, cetostearyl alcohol, glycerol monostearate and sodium lauryl sulphate as well as hydroxypropylcellulose, butylmethacrylat-(2-dimethylaminoethyl)methacrylat-methylmethacrylat-copolymer, polyacrylic acid, polyvinyl alcohol and povidone K17 were included in the study. It could be shown that povidone K17 effectively prevents recrystallization in solid solutions containing 20% (m/m) of nimodipine during storage at +25 degrees C over silica gel thereby ensuring a substantial increase in the dissolution rate and degree of supersaturation in water. On the contrary, stabilization by solubility enhancement was only successful at drug loadings not exceeding 1% (m/m) using polyethylene glycol 300 as solubility enhancing additive. PMID:16472995

Urbanetz, Nora Anne

2006-05-01

404

Water absorption in polyethylene under external electric fields.  

PubMed

Monte Carlo simulations of the solubility and structure of water in polyethylene in thermodynamic equilibrium with liquid water were performed in external fields ranging from 2 x 10(5) to 4 x 10(9) V/m. For a given equilibrium temperature and pressure, the water solubility decreases at higher fields. This occurs since it is energetically favorable for water molecules to be in the pure water phase than in the polyethylene matrix at high field strengths, and results in an increased density in the water phase. However, fields relevant to high voltage conduction (in the absence of defects that can lead to large local field strengths) do not change the solubility. In addition, at large fields the number of water clusters decreases for all cluster sizes. The rate of decrease is highest for large clusters, and a larger fraction of water molecules exist as monomers in the polyethylene matrix at high fields. Large fields also cause alignment of the water molecules, which leads to more clusters with linear topologies and hence an increase in the cluster radius of gyration. PMID:17640146

Johansson, E; Bolton, K; Ahlström, P

2007-07-14

405

Absorption current behaviour of polyethylene/silica nanocomposites  

NASA Astrophysics Data System (ADS)

Absorption current is an important characteristic of polymers with regard to their time-domain response to a direct current (DC) poling field. This is because the results of absorption current measurements can be used to gain understanding of the relationship between space charge accumulation and movement. In semicrystalline polyethylene, for example, charge accumulation is likely to be influenced by the presence of charge trapping sites, which are associated with interfaces between the crystalline and amorphous phases. With the addition of a nanofiller, the charge transport mechanism will become more complicated than in the unfilled polymer, as the inclusion of the nanofiller will introduce nanofiller/polymer interfaces. The presence of such interfaces will affect the current flow due to the introduction or modification of the distribution of trapping sites within the system. In this paper, we report on an investigation into the absorption current behaviour of polyethylene nanocomposites containing 0 wt%, 2 wt%, 5 wt% and 10 wt% of silica nanofiller, either untreated or treated using trimethoxy(propyl)silane coupling agent. Our results indicate that the absorption current behaviour of the polyethylene was affected by the presence of the nanosilica. While the current behaviour through the unfilled polymer decreases with time in a conventional manner, all nanocomposites reveal an initial decrease followed by a period in which the current increases with increasing time of DC field application.

Lau, K. Y.; Vaughan, A. S.; Chen, G.; Hosier, I. L.; Holt, A. F.

2013-11-01

406

Wear Analysis in THA Utilizing Oxidized Zirconium and Crosslinked Polyethylene  

PubMed Central

Oxidized zirconium, a material with a ceramic surface on a metal substrate, and highly cross-linked polyethylene are two materials developed to reduce wear. We measured in vivo femoral head penetration in patients with these advanced bearings. We hypothesized the linear wear rates would be lower than those published for cobalt-chrome and standard polyethylene. We retrospectively reviewed a select series of 56 THAs in a relatively young, active patient population utilizing oxidized zirconium femoral heads and highly cross-linked polyethylene acetabular liners. Femoral head penetration was determined using the Martell computerized edge-detection method. All patients were available for 2-year clinical and radiographic followup. True linear wear was 4 ?m/year (95% confidence intervals, ± 59 ?m/year). The early wear rates in this cohort of relatively young, active patients were low and we believe justify the continued study of these alternative bearing surfaces. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Garvin, Kevin L.; Mangla, Jimmi; Murdoch, Nathan; Martell, John M.

2008-01-01

407

Reasons of Revision for First-Generation Highly Crosslinked Polyethylenes  

PubMed Central

Over a ten-year period, we prospectively evaluated the reasons for revision for contemporary and highly crosslinked polyethylene formulations in a multicenter retrieval program. 212 consecutive retrievals were classified as conventional gamma-inert sterilized liners (n=37), annealed (Crossfire™, n=72), or remelted (Longevity™, XLPE, Durasul; n=93). The most frequent reasons for revision were loosening (35%), instability (28%) and infection (21%) and were not related to polyethylene formulation (p = 0.17). Annealed and remelted liners had comparable linear penetration rates (0.03 and 0.04 mm/y, respectively, on average) and were significantly lower than conventional retrievals (0.11 mm/y; p ? 0.0005). This retrieval study including first-generation highly crosslinked liners demonstrated lower wear than conventional polyethylene. While loosening remained the most prevalent reason for revision, we could not demonstrate a relationship between wear and loosening. The long-term clinical performance of first-generation highly crosslinked remains promising, based on the mid-term outcomes of the components documented in this study.

Kurtz, Steven M.; Medel, Francisco; MacDonald, Daniel; Parvizi, Javad; Kraay, Matthew; Rimnac, Clare

2010-01-01

408

Comparative stability studies of poly(2-methyl-2-oxazoline) and poly(ethylene glycol) brush coatings.  

PubMed

Non-fouling surfaces that resist non-specific adsorption of proteins, bacteria, and higher organisms are of particular interest in diverse applications ranging from marine coatings to diagnostic devices and biomedical implants. Poly(ethylene glycol) (PEG) is the most frequently used polymer to impart surfaces with such non-fouling properties. Nevertheless, limitations in PEG stability have stimulated research on alternative polymers that are potentially more stable than PEG. Among them, we previously investigated poly(2-methyl-2-oxazoline) (PMOXA), a peptidomimetic polymer, and found that PMOXA shows excellent anti-fouling properties. Here, we compare the stability of films self-assembled from graft copolymers exposing a dense brush layer of PEG and PMOXA side chains, respectively, in physiological and oxidative media. Before media exposure both film types prevented the adsorption of full serum proteins to below the detection limit of optical waveguide in situ measurements. Before and after media exposure for up to 2 weeks, the total film thickness, chemical composition, and total adsorbed mass of the films were quantified using variable angle spectroscopic ellipsometry (VASE), X-ray photoelectron spectroscopy (XPS), and optical waveguide lightmode spectroscopy (OWLS), respectively. We found (i) that PMOXA graft copolymer films were significantly more stable than PEG graft copolymer films and kept their protein-repellent properties under all investigated conditions and (ii) that film degradation was due to side chain degradation rather than due to copolymer desorption. PMID:22589044

Pidhatika, Bidhari; Rodenstein, Mathias; Chen, Yin; Rakhmatullina, Ekaterina; Mühlebach, Andreas; Acikgöz, Canet; Textor, Marcus; Konradi, Rupert

2012-12-01

409

Preparation and characterization of active site protected poly(ethylene glycol)-avidin bioconjugates.  

PubMed

Avidin was modified with poly(ethylene glycol) in the presence of a biotin binding site protective agent synthesised by imminobiotin conjugation to branched 20 kDa PEG. Avidin was incubated with imminobiotin-PEG and reacted with high amounts of 5, 10 or 20 kDa PEG to modify the protein amino groups. Circular dichroism demonstrated that the extensive PEGylation does not alter the protein conformational structure. The affinity of avidin-PEG conjugates for biotin and biotinylated antibodies depended on the PEG size or the use of a protective agent. Avidin-PEG 10 and 20 kDa prepared in the presence of imminobiotin-PEG maintained 100% of the native affinity for biotin. The 5 kDa PEG derivative and the ones obtained without biotin site protection maintained 79-85% of the native affinity. The affinity for biotinylated antibodies decreased to 35% when the conjugation was performed without imminobiotin-PEG, while the conjugates obtained with high-molecular-weight PEGs in the presence of protective agent displayed high residual affinity. All conjugates possessed negligible antigenicity and immunogenicity. PEGylation greatly prolonged the avidin permanence in the circulation, reduced its disposition in the liver and kidneys and promoted accumulation into solid tumors. PEGylation was found to prevent the protein cell uptake, either by phagocytosis or pinocytosis. PMID:15964691

Salmaso, Stefano; Semenzato, Alessandra; Bersania, Sara; Chinol, Marco; Paganelli, Giovanni; Caliceti, Paolo

2005-10-30

410

Transesterification in poly(ethylene terephthalate) and poly(ethylene naphthalate 2,6-dicarboxylate) blends: model compounds study  

Microsoft Academic Search

Kinetics of transesterification reaction in poly(ethylene terephthalate)–poly(ethylene naphthalate 2,6-dicarboxylate), PET–PEN, blends resulting from melt processing was simulated using model compounds of ethylene dibenzoate (BEB) and ethylene dinaphthoate (NEN). The exchange reaction between BEB and NEN was followed by 1H NMR spectroscopy using signals from the aliphatic protons of ethylene glycol moieties at 4.66 and 4.78ppm, respectively. The first-order kinetics was

L. Alexandrova; A. Cabrera; M. A. Hernández; M. J. Cruz; M. J. M. Abadie; O. Manero; D. Likhatchev

2002-01-01

411

Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite  

PubMed Central

Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50?phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis.

Ahmad, Mazatusziha; Wahit, Mat Uzir; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

2012-01-01

412

Mechanical, rheological, and bioactivity properties of ultra high-molecular-weight polyethylene bioactive composites containing polyethylene glycol and hydroxyapatite.  

PubMed

Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50?phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

Ahmad, Mazatusziha; Uzir Wahit, Mat; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

2012-01-01

413

Human polyethylene granuloma tissues inhibit bone healing in a novel xenograft animal model.  

PubMed

During revision of a conventional polyethylene joint replacement, surgeons usually remove the source of osteolysis (polyethylene) but cannot always remove all of the polyethylene granuloma tissues. We developed a human/rat xenograft model to investigate the effects of polyethylene granuloma tissues on bone healing. Human osteoarthritic and periprosthetic tissues collected during primary and revision hip arthroplasty surgeries were transplanted into the distal femora of athymic nude rats. After 3 weeks in vivo, there was a significant difference in the bone volume fraction (Vf ) between empty, primary, and revision defects (p?=?0.02), with a lower Vf in defects with revision granuloma tissues compared to defects with primary osteoarthritic tissues. Polyethylene granuloma tissues in trabecular bone defects inhibited bone healing. Therefore, debridement around a metal-on-polyethylene hip replacement may shorten the time it takes to achieve secondary stability around a revision hip replacement. PMID:24619566

Esposito, Christina I; Oliver, Rema A; Campbell, Patricia A; Yu, Yan; Walter, William L; Walter, William K; Walsh, William R

2014-06-01

414

Universal concept for the implementation of a single cleavable unit at tunable position in functional poly(ethylene glycol)s.  

PubMed

Poly(ethylene glycol) (PEG) with acid-sensitive moieties gained attention particularly for various biomedical applications, such as the covalent attachment of PEG (PEGylation) to protein therapeutics, the synthesis of stealth liposomes, and polymeric carriers for low-molecular-weight drugs. Cleavable PEGs are favored over their inert analogues because of superior pharmacodynamic and/or pharmacokinetic properties of their formulations. However, synthetic routes to acetal-containing PEGs published up to date either require enormous efforts or result in ill-defined materials with a lack of control over the molecular weight. Herein, we describe a novel methodology to implement a single acetaldehyde acetal in well-defined (hetero)functional poly(ethylene glycol)s with total control over its position. To underline its general applicability, a diverse set of initiators for the anionic polymerization of ethylene oxide (cholesterol, dibenzylamino ethanol, and poly(ethylene glycol) monomethyl ether (mPEG)) was modified and used to synthesize the analogous labile PEGs. The polyether bearing the cleavable lipid had a degree of polymerization of 46, was amphiphilic and exhibited a critical micelle concentration of 4.20 mg·L(-1). From dibenzylamino ethanol, three heterofunctional PEGs with different molecular weights and labile amino termini were generated. The transformation of the amino functionality into the corresponding squaric acid ester amide demonstrated the accessibility of the cleavable functional group and activated the PEG for protein PEGylation, which was exemplarily shown by the attachment to bovine serum albumin (BSA). Furthermore, turning mPEG into a macroinitiator with a cleavable hydroxyl group granted access to a well-defined poly(ethylene glycol) derivative bearing a single cleavable moiety within its backbone. All the acetal-containing PEGs and PEG/protein conjugates were proven to degrade upon acidic treatment. PMID:23256621

Dingels, Carsten; Müller, Sophie S; Steinbach, Tobias; Tonhauser, Christine; Frey, Holger

2013-02-11

415

Infliximab attenuates activated charcoal and polyethylene glycol aspiration-induced lung injury in rats.  

PubMed

Aspiration is a serious complication of gastrointestinal (GI) decontamination procedure. Studies have shown that tumor necrosis factor-? (TNF-?) blockers have beneficial effects on lung injury. Therefore, the authors investigated the attenuation by infliximab (INF) on activated charcoal (AC)- and polyethylene glycol (PEG)-induced lung injury in rat model. Forty-two male Sprague-Dawley rats were allotted into 1 of 6 groups: saline (NS), activated charcoal (AC), polyethylene glycol (PEG), NS+INF treated, AC+INF treated, and PEG+INF treated. All materials were aspirated into the lungs at a volume of 1 mL/kg. Before aspiration, the rats were injected subcutaneously with INF. Seven days later, both lungs and serum specimens in all groups were evaluated histopathologically, immunohistochemically, and biochemically. Following aspiration of AC and PEG, evident histopathological changes were assigned in the lung tissue that were associated with increased expression of inducible nitric oxide synthase (iNOS), increased serum levels of oxidative stress markers (malondialdehyde [MDA], surfactant protein-D [SP-D], TNF-?), and decreased antioxidant enzyme (glutathione peroxidase [GSH-Px]) activities. INF treatment significantly decreased the elevated serum MDA and TNF-? levels and increased serum GSH-Px levels. Furthermore, the current results show that there is a significant reduction in the activity of iNOS in lung tissue and increased serum SP-D levels of AC and PEG aspiration-induced lung injury with INF treatment. These findings suggest that INF attenuates lung inflammation and prevents GI decontamination agent-induced lung injury in rats. PMID:22394288

Güzel, Aygül; Günaydin, Mithat; Güzel, Ahmet; Alaçam, Hasan; Murat, Naci; Gacar, Ayhan; Güvenç, Tolga

2012-04-01

416

Polyethylene waste form: Evaluation of explosion and fire hazards. Final report  

Microsoft Academic Search

A Proposed polyethylene waste form consists of a hot-extruded, non-porous mix of equal weights of polyethylene and granular sodium nitrate, slightly contaminated with heavy metal salts. The experiments and theoretical analysis detailed in this report were done to evaluate the risks for self-accelerating thermal decomposition, explosion, and detonation of polyethylene mixed with sodium nitrate. The study included the proposed waste

A. Block-Bolten; D. Olson; P. A. Persson; F. Sandstrom

1991-01-01

417

Structure–property relationships in polyethylene blends: the effect of morphology on electrical breakdown strength  

Microsoft Academic Search

Blends of linear and branched polyethylene were prepared covering the composition range 1–20% linear polyethylene, and three\\u000a thermal treatments were subsequently chosen to produce a range of different morphologies. Isothermal crystallization at 124\\u000a °C gives rise to compact linear inclusions within a matrix of branched polyethylene, isothermal crystallization at 115 °C\\u000a produces an open, banded spherulitic morphology and, finally, quenching

I. L. HOSIER; A. S. VAUGHAN; S. G SWINGLER

1997-01-01

418

Effect of Polyethylene Functionalization on Mechanical Properties and Morphology of PE\\/SiO2 Composites  

Microsoft Academic Search

In this study composites of high density polyethylene (HDPE) with various SiO2 content were prepared by melt compounding using maleic anhydride grafted polyethylene (PE-g-MAH) as a compatibilizer. The composites containing 2, 4 and 6% by weight of SiO2 particles were melt-blended in a co-rotating twin screw extruder. In all composites, polyethylene-graft-maleic anhydride copolymer (PE-g-MAH, with 0.85% maleic anhydride content) was

Karol Bula; Teofil Jesionowski

2010-01-01

419

Metal-on-Metal vs Metal-on-Improved Polyethylene Bearings in Total Hip Arthroplasty  

Microsoft Academic Search

Major weaknesses of total hip arthroplasty (THA) in the 20th century were polyethylene wear and dislocation. Efforts to improve THA took several directions including improvement of polyethylene and use of metal-on-metal (MoM) articulations. Metal-on-metal articulations showed excellent early results, but concerns mount over hypersensitivity and increasing failure. This study compares our experience with MoM and metal-on-improved polyethylene (MoIP) bearings in

Ryan G. Molli; Adolph V. Lombardi; Keith R. Berend; Joanne B. Adams; Michael A. Sneller

2011-01-01

420

Thermal characterization of Ag and Ag + N ion implanted ultra-high molecular weight polyethylene (UHMWPE)  

Microsoft Academic Search

Most of total hip joints are composed of ultra-high molecular weight polyethylene (UHMWPE ). However, as ultra-high molecular weight polyethylene is too stable in a body, wear debris may accumulate and cause biological response such as bone absorption and loosening of prosthesis. In this study, ultra-high molecular weight polyethylene samples were Ag and Ag+N hybrid ion implanted by using MEVVA

E. Sokullu Urkac; A. Oztarhan; F. Tihminlioglu; N. Kaya; D. Ila; C. Muntele; S. Budak; E. Oks; A. Nikolaev; A. Ezdesir; Z. Tek

2007-01-01

421

Relationship Between Bond Strength and Crystallinity of High Polymers-Polyethylene, Polyethyleneterephthalate, and Nylon  

Microsoft Academic Search

The effect of crystallinity of polyethylene on the peel strength of aluminum plate-polyethylene-aluminum foil laminate was investigated. The 180° peel strength increased by rapid cooling with water, ice water, or liquid nitrogen after bonding with hot-melt polyethylene compared with slow cooling with air at room temperature. It was concluded that the increase of peel strength by rapid cooling was due

Kazumune Nakao

1972-01-01

422

Synthesis and bioactivities of poly(ethylene glycol)–chitosan hybrids  

Microsoft Academic Search

Poly(ethylene glycol)–chitosan hybrids of various molecular weights having different degree of substitution were synthesized, by reductive N-alkylation of chitosan with poly(ethylene glycol) aldehyde, to study their bioactivities. The influence of these chitosan derivatives on the reactive oxygen species generation from canine polymorphonuclear leukocyte cells was investigated in vitro by chemiluminescence response. Reactive oxygen species generation by the influence of poly(ethylene

T Muslim; M Morimoto; H Saimoto; Y Okamoto; S Minami; Y Shigemasa

2001-01-01

423

Plasmid DNA partitioning and separation using poly(ethylene glycol)/poly(acrylate)/salt aqueous two-phase systems.  

PubMed

Phase diagrams of poly(ethylene glycol)/polyacrylate/Na(2)SO(4) systems have been investigated with respect to polymer size and pH. Plasmid DNA from Escherichia coli can depending on pH and polymer molecular weight be directed to a poly(ethylene glycol) or to a polyacrylate-rich phase in an aqueous two-phase system formed by these polymers. Bovine serum albumin (BSA) and E. coli homogenate proteins can be directed opposite to the plasmid partitioning in these systems. Two bioseparation processes have been developed where in the final step the pDNA is partitioned to a salt-rich phase giving a total process yield of 60-70%. In one of them the pDNA is partitioned between the polyacrylate and PEG-phases in order to remove proteins. In a more simplified process the plasmid is partitioned to a PEG-phase and back-extracted into a Na(2)SO(4)-rich phase. The novel polyacrylate/PEG system allows a strong change of the partitioning between the phases with relatively small changes in composition or pH. PMID:22391492

Johansson, Hans-Olof; Matos, Tiago; Luz, Juliana S; Feitosa, Eloi; Oliveira, Carla C; Pessoa, Adalberto; Bülow, Leif; Tjerneld, Folke

2012-04-13

424

Adhesion, Growth, and Maturation of Vascular Smooth Muscle Cells on Low-Density Polyethylene Grafted with Bioactive Substances  

PubMed Central

The attractiveness of synthetic polymers for cell colonization can be affected by physical, chemical, and biological modification of the polymer surface. In this study, low-density polyethylene (LDPE) was treated by an Ar+ plasma discharge and then grafted with biologically active substances, namely, glycine (Gly), polyethylene glycol (PEG), bovine serum albumin (BSA), colloidal carbon particles (C), or BSA+C. All modifications increased the oxygen content, the wettability, and the surface free energy of the materials compared to the pristine LDPE, but these changes were most pronounced in LDPE with Gly or PEG, where all the three values were higher than in the only plasma-treated samples. When seeded with vascular smooth muscle cells (VSMCs), the Gly- or PEG-grafted samples increased mainly the spreading and concentration of focal adhesion proteins talin and vinculin in these cells. LDPE grafted with BSA or BSA+C showed a similar oxygen content and similar wettability, as the samples only treated with plasma, but the nano- and submicron-scale irregularities on their surface were more pronounced and of a different shape. These samples promoted predominantly the growth, the formation of a confluent layer, and phenotypic maturation of VSMC, demonstrated by higher concentrations of contractile proteins alpha-actin and SM1 and SM2 myosins. Thus, the behavior of VSMC on LDPE can be regulated by the type of bioactive substances that are grafted.

Parizek, Martin; Slepickova Kasalkova, Nikola; Bacakova, Lucie; Bacakova, Marketa; Lisa, Vera; Svorcik, Vaclav

2013-01-01

425

Nonfouling poly(ethylene oxide) layers end-tethered to polydopamine.  

PubMed

Nonfouling surfaces capable of reducing protein adsorption are highly desirable in a wide range of applications. Coating of surfaces with poly(ethylene oxide) (PEO), a water-soluble, nontoxic, and nonimmunogenic polymer, is most frequently used to reduce nonspecific protein adsorption. Here we show how to prepare dense PEO brushes on virtually any substrate by tethering PEO to polydopamine (PDA)-modified surfaces. The chain lengths of hetero-bifunctional PEOs were varied in the range of 45-500 oxyethylene units (M(n) = 2000-20,000). End-tethering of PEO chains was performed through amine and thiol headgroups from reactive polymer melts to minimize excluded volume effects. Surface plasmon resonance (SPR) was applied to investigate the adsorption of model protein solutions and complex biologic medium (human blood plasma) to the densely packed PEO brushes. The level of protein adsorption of human serum albumin and fibrinogen solutions was below the detection limit of the SPR measurements for all PEO chains end-tethered to PDA, thus exceeding the protein resistance of PEO layers tethered directly on gold. It was found that the surface resistance to adsorption of lysozyme and human blood plasma increased with increasing length and brush character of the PEO chains end-tethered to PDA with a similar or better resistance in comparison to PEO layers on gold. Furthermore, the chain density, thickness, swelling, and conformation of PEO layers were determined using spectroscopic ellipsometry (SE), dynamic water contact angle (DCA) measurements, infrared reflection-absorption spectroscopy (IRRAS), and vibrational sum-frequency-generation (VSFG) spectroscopy, the latter in air and water. PMID:22989020

Pop-Georgievski, Ognen; Verreault, Dominique; Diesner, Mark-Oliver; Proks, Vladimír; Heissler, Stefan; Rypá?ek, František; Koelsch, Patrick

2012-10-01

426

Manufacturing, structure and properties of recycled polyethylene terephthalate /liquid crystal polymer/montmorillonite clay nanocomposites  

NASA Astrophysics Data System (ADS)

Polyethylene terephthalate (PET)/liquid crystal polymer (LCP)/monthmorillonite clay (MMT) compositions were obtained by melt mixing. Their mechanical, structural, rheological and thermal properties were investigated.

Japins, Guntis; Berzina, Rita; Zicans, Janis; Merijs Meri, Remo; Ivanova, Tatjana; Kalkis, Valdis; Reinholds, Ingars

2013-12-01

427

Cementitious building material incorporating end-capped polyethylene glycol as a phase change material  

DOEpatents

A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

Salyer, Ival O. (Dayton, OH); Griffen, Charles W. (Mason, OH)

1986-01-01

428

Effect of cast solvent on the electron transfer reaction for poly(ethylene oxide)-modified myoglobin on the electrode in poly(ethylene oxide) oligomers.  

PubMed

Myoglobin from horse skeletal muscle was modified with poly(ethylene oxide) (PEO) with an average molecular weight of 2000 or 5000. Myoglobin was soluble after this modification in several organic solvents and PEO oligomers. The electron transfer reactions of PEO-modified myoglobin cast on the indium tin oxide (ITO) glass electrode were investigated by cyclic voltammetry. The PEO-modified myoglobin, cast on the electrode from water or a methanol solution, showed quasi-reversible redox reactions in PEO (average MW of 400). On the other hand, no redox response was seen in PEO-modified myoglobin cast on it using chloroform or benzene as a casting solvent. A clear redox response of the PEO-modified myoglobin was observed after methanol treatment of these layers cast from chloroform or a benzene solution. This suggests that the conformational change of the adsorbed PEO-modified myoglobin layer on the ITO electrode cast from chloroform or a benzene solution was not irreversible. The cast condition of PEO-modified myoglobin on the ITO glass electrode was revealed to affect the electron transfer reaction for protein considerably in PEO oligomers. PMID:9095367

Kawahara, N Y; Ohkubo, W; Ohno, H

1997-01-01

429

Proteomic and phosphoproteomic analysis of polyethylene glycol-induced osmotic stress in root tips of common bean (Phaseolus vulgaris L.)  

PubMed Central

Previous studies have shown that polyethylene glycol (PEG)-induced osmotic stress (OS) reduces cell-wall (CW) porosity and limits aluminium (Al) uptake by root tips of common bean (Phaseolus vulgaris L.). A subsequent transcriptomic study suggested that genes related to CW processes are involved in adjustment to OS. In this study, a proteomic and phosphoproteomic approach was applied to identify OS-induced protein regulation to further improve our understanding of how OS affects Al accumulation. Analysis of total soluble proteins in root tips indicated that, in total, 22 proteins were differentially regulated by OS; these proteins were functionally categorized. Seventy-seven per- cent of the total expressed proteins were involved in metabolic pathways, particularly of carbohydrate and amino acid metabolism. An analysis of the apoplastic proteome revealed that OS reduced the level of five proteins and increased that of seven proteins. Investigation of the total soluble phosphoproteome suggested that dehydrin responded to OS with an enhanced phosphorylation state without a change in abundance. A cellular immunolocalization analysis indicated that dehydrin was localized mainly in the CW. This suggests that dehydrin may play a major protective role in the OS-induced physical breakdown of the CW structure and thus maintenance of the reversibility of CW extensibility during recovery from OS. The proteomic and phosphoproteomic analyses provided novel insights into the complex mechanisms of OS-induced reduction of Al accumulation in the root tips of common bean and highlight a key role for modification of CW structure.

Horst, Walter Johannes

2013-01-01

430

Vascular tumor in metal-on-polyethylene THA requiring hemipelvectomy.  

PubMed

Total hip arthroplasty with metal-on-polyethylene implants and metal-on-metal articulations have been an area of recent interest. This article describes a patient with a persistent small soft tissue mass on the anterior groin following total hip arthroplasty with negative findings on infection workup, including blood work and aspiration. Subsequent biopsy findings were consistent with organizing thrombus and necrosis. It then developed into an expansile soft tissue groin mass with significant femoral and pelvic bony destruction and soft tissue infiltration. Metallosis, the formation of a pseudocapsule, and aseptic lymphocyte vasculitis-associated lesions have also been an area of interest following adult hip reconstruction. Occasionally, the formation of subsequent lesions make revision surgery impossible to perform due to bony destruction and soft tissue limitations. Although few in number, most studies or cases that have linked metal-on-metal implants to pseudotumors have been treated with revision surgery and replacement of articulating surfaces. This case highlights a metal-on-polyethylene total hip arthroplasty with a mass presenting with pseudotumor-like characteristics. However, final histology demonstrated fibroadipose tissue with fat necrosis and fibrosis, thickened vascular vessels, and diffuse chronic inflammation with lymphocytic infiltrates, which are more consistent with an atypical inflammatory vascular tumor. The current case illustrates treatment difficulties and provides surgical options for when this event occurs. Although aseptic lymphocyte vasculitis-associated lesions have been observed with metal-on-polyethylene articulations, the multiorgan involvement in this case is unique. In this case, radical excision with hemipelvectomy and complex flap closure was a last resort treatment solution that staved off the prospect of patient mortality. PMID:23823059

Lee, Jason H; Le, Vu H; Steinhoff, Amy; Hoang, Bang H

2013-07-01

431

Investigation of the fire endurance of borated polyethylene shielding material  

SciTech Connect

We conducted nine experiments to investigate the fire endurance of a borated polyethylene shielding material to be used in the Engineering Demonstration System. Several chemistry tests were also done. The shielding material was found to melt at 93.5/degree/C, decompose at 230/degree/C, and ignite at 350/degree/C. Five fire tests were done in a realistic configuration and four tests in a pessimistic configuration. The material easily passed all nine tests. In each case, the shielding material never reached ignition temperature and was found acceptable in this proposed application. 7 refs., 10 figs., 3 tabs.

Foote, K.L.

1988-06-17

432

Pyrolysis Pathways of Sulfonated Polyethylene, an Alternative Carbon Fiber Precursor  

SciTech Connect

Sulfonated polyethylene is an emerging precursor for the production of carbon fibers. Pyrolysis of sulfonated polyethylene was characterized by thermogravimetric analysis (TGA). n-heptane-4-sulfonic acid (H4S) was selected as a model compound for the study of sulfonated polyethylene. Density functional theory and conventional transition state theory were used to determine the rate constants of pyrolysis for H4S from 300-1000 K. Multiple reaction channels from two different mechanisms were explored: 1) internal five-centered elimination (Ei 5) and 2) radical chain reaction. The pyrolysis of H4S was simulated with kinetic Monte Carlo (kMC) to obtain TGA plots that compared favorably to experiment. We observed that at tem- peratures < 550 K, the radical mechanism was dominant and yielded the trans-alkene, whereas cis-alkene was formed at higher temperatures from the internal elimination. The maximum rates of % mass loss became independent of initial OH radical concentration at 440-480 K. Experimentally, the maximum % mass loss occurred from 440-460 K (heating rate dependent). Activation energies derived from the kMC-simulated TGAs of H4S (26-29 kcal/mol) agreed with experiment for sulfonated polyethylene ( 31 kcal/mol). The simulations revealed that in this region, decomposition of radical HOSO2 became competitive to H abstraction by HOSO2, making OH the carrying radical for the reaction chain. The maximum rate of % mass loss for internal elimination was observed at temperatures > 600 K. Low-scale carbonization utilizes temperatures < 620 K; thus, internal elimination will not be competitive. Ei5 elimination has been studied for sulfoxides and sulfones, but this represents the first study of internal elimination in sulfonic acids. Nonlinear Arrhenius plots were found for all bimolecular reactions. The most significant nonlinear behavior was observed for reactions where the barrier was small. For reactions with low activation barriers, nonlinearity was traced to conflicting trends between the exponential temperature dependence of the energetic term and the temperature dependence of the vibrational partition function of the transitional modes.

Younker, Jarod M [ORNL; Saito, Tomonori [ORNL; Hunt, Marcus A [ORNL; Beste, Ariana [ORNL; Naskar, Amit K [ORNL

2013-01-01

433

Polyethylene glycol-based homologated ligands for nicotinic acetylcholine receptors?  

PubMed Central

A homologous series of polyethylene glycol (PEG) monomethyl ethers were conjugated with three ligand series for nicotinic acetylcholine receptors. Conjugates of acetylaminocholine, the cyclic analog 1-acetyl-4,4-dimethylpiperazinium, and pyridyl ether A-84543 were prepared. Each series was found to retain significant affinity at nicotinic receptors in rat cerebral cortex with tethers of up to six PEG units. Such compounds are hydrophilic ligands which may serve as models for fluorescent/affinity probes and multivalent ligands for nAChR.

Scates, Bradley A.; Lashbrook, Bethany L.; Chastain, Benjamin C.; Tominaga, Kaoru; Elliott, Brandon T.; Theising, Nicholas J.; Baker, Thomas A.; Fitch, Richard W.

2010-01-01

434

Aspiration of barium-impregnated polyethylene spheres by a dog.  

PubMed

This case report describes an 11-year-old Belgian Malinois dog with acute onset of cough caused by aspiration of barium-impregnated polyethylene spheres (BIPS) and pneumonia following an episode of suspected gastric dilation. Although bronchoscopic retrieval of the BIPS was largely unsuccessful, the dog recovered uneventfully, with most of the BIPS being coughed out and swallowed over a 1-month period. Aspiration of BIPS should be considered a potential complication of their administration. Furthermore, endoscopic removal of aspirated BIPS is challenging and may not be indicated because of their inert nature and possible self-clearance. PMID:20529021

Greci, V; Bissett, S A; Copple, C N; Hawkins, E C

2010-05-01

435

Structural changes in polyethylene terephthalate in production of nuclear membranes  

SciTech Connect

The effect of irradiation with high-energy ions on the structure of polyethylene terephthalate (PETP) was investigated. It was found that irradiation causes additional orientation of the polymer macromolecules in the region of injuries. When PETP in aqueous solutions is treated with a base, the character of the change in the degree of orientation of the polymer as a function of the etching time differs significantly from the behavior of the starting PETP. The differences are determined by the initial additional orientation of the polymer during irradiation and the predominant removal of the damaged part of the polymer during chemical treatment. 10 refs., 4 figs.

Vilenskii, A.I.; Oleinikov, V.A.; Mchedishvili, B.V. [and others

1992-07-01

436

Reduction in tumor formation on polyethylene by collagen immobilization.  

PubMed

After surface modification with collagen immobilization through covalent binding, porous polyethylene pieces were implanted subcutaneously into the back of rats for 1 year and the tumorigenesis-reducing effect was examined. In the virgin pieces without collagen immobilization, tumors were observed in 11 out of 24 pieces implanted (45.8%). On the other hand, in the collagen immobilized pieces a tumor was found only in one of 24 implanted pieces (4.2%). These results suggest that immobilization of collagen on the surface of an artificial material through covalent binding is very effective for a reduction of tumor formation. PMID:10163366

Kinoshita, Y; Kuzuhara, T; Kobayashi, M; Ikada, Y

1995-01-01

437

Effective UV radiation dose in polyethylene exposed to weather  

NASA Astrophysics Data System (ADS)

In this work we quantified the effective UV radiation dose in orange and colorless polyethylene samples exposed to weather in the city of Aguascalientes, Ags. Mexico. The spectral distribution of solar radiation was calculated using SMART 2.9.5.; the samples absorption properties were measured using UV-Vis spectroscopy and the quantum yield was calculated using samples reflectance properties. The determining factor in the effective UV dose is the spectral distribution of solar radiation, although the chemical structure of materials is also important.

González-Mota, R.; Soto-Bernal, J. J.; Rosales-Candelas, I.; Calero Marín, S. P.; Vega-Durán, J. T.; Moreno-Virgen, R.

2009-09-01

438

Human Ribonuclease with a Pendant Poly(Ethylene Glycol) Inhibits Tumor Growth in Mice1  

PubMed Central

Human pancreatic ribonuclease (RNase 1) is a small secretory protein that catalyzes the cleavage of RNA. This highly cationic enzyme can enter human cells spontaneously but is removed rapidly from circulation by glomerular filtration. Here, this shortcoming is addressed by attaching a poly(ethylene glycol) (PEG) moiety to RNase 1. The pendant has no effect on ribonucleolytic activity but does increase persistence in circulation. The RNase 1-PEG conjugates inhibit the growth of tumors in a xenograft mouse model of human lung cancer. Both retention in circulation and tumor growth inhibition correlate with the size of the pendant PEG. A weekly dose of the 60-kDa conjugate at 1 µmol/kg inhibited nearly all tumor growth without affecting body weight. Its molecular efficacy is ?5000-fold greater than that of erlotinib, which is a small molecule in clinical use for the treatment of lung cancer. These data demonstrate that the addition of a PEG moiety can enhance the in vivo efficacy of human proteins that act within cells and highlight a simple means of converting an endogenous human enzyme into a cytotoxin with potential clinical utility.

Rutkoski, Thomas J; Kink, John A; Strong, Laura E; Raines, Ronald T

2013-01-01

439

Single-Monomer Formulation of Polymerized Polyethylene Glycol Diacrylate as a Nonadsorptive Material for Microfluidics  

PubMed Central

Nonspecific adsorption in microfluidic systems can deplete target molecules in solution and prevent analytes, especially those at low concentrations, from reaching the detector. Polydimethylsiloxane (PDMS) is a widely used material for microfluidics, but is prone to nonspecific adsorption, necessitating complex chemical modification processes to address this issue. An alternative material to PDMS that does not require subsequent chemical modification is presented here. Poly(ethylene glycol) diacrylate (PEGDA) mixed with photoinitiator forms on exposure to UV radiation a polymer with inherent resistance to nonspecific adsorption. Optimization of the polymerized PEGDA (poly-PEGDA) formula imbues this material with some of the same properties, including optical clarity, water stability, and low background fluorescence, that make PDMS so popular. Poly-PEGDA demonstrates less nonspecific adsorption than PDMS over a range of concentrations of flowing fluorescently tagged bovine serum albumin solutions, and poly-PEGDA has greater resistance to permeation by small hydrophobic molecules than PDMS. Poly-PEGDA also exhibits long-term (hour scale) resistance to nonspecific adsorption compared to PDMS when exposed to a low (1 µg/mL) concentration of a model adsorptive protein. Electrophoretic separations of amino acids and proteins resulted in symmetrical peaks and theoretical plate counts as high as 4 × 105/m. Poly-PEGDA, which displays resistance to nonspecific adsorption, could have broad use in small volume analysis and biomedical research.

Rogers, Chad I.; Pagaduan, Jayson V.; Nordin, Gregory P.; Woolley, Adam T.

2011-01-01

440

Association of polyethylene friction and thermal unfolding of interfacial albumin molecules  

NASA Astrophysics Data System (ADS)

Under the articulation of artificial joints, ultra-high molecular weight polyethylene (UHMWPE) acts as a bearing surface under the lubrication of synovial fluid containing various proteins. Albumin is the most abundant composition and acts as the interfacial molecule in the boundary lubrication regime. The dissipated energy including thermal energy from the tribological process may lead to the conformational change of albumin molecules. In this study, a series of experiments were designed and carried out to investigate the association of thermal unfolding albumin and the frictional characteristics of highly-crosslinked UHMWPE (x-UHMWPE). An accelerated oxidation experiment was used to prepare x-UHMWPE with an oxidized surface. Analysis of the albumin protein by circular dichroism (CD) spectroscopy was performed to detect the conformational changes during a thermal process. In addition, a molecular simulation was performed to understand the structural change of albumin at various temperatures and the exposed hydrophobic contact areas. Linear reciprocating frictional tests were carried out to obtain the start-up friction coefficients. The results indicate that a decrease of ?-helix content and an unfolding of the secondary structure of albumin were observed with increasing temperatures which may come from the frictional heat of joint articulation process. The conformational change of albumin differentiates the frictional characteristics for x-UHMWPE with different oxidation levels. A model, describing that the properties of the lubricating molecules and articulating surfaces may affect the adsorption of the boundary lubrication thin film which is critical to the tribological behavior, is proposed.

Fang, Hsu-Wei; Shih, Meng-Lin; Zhao, Jian-Hua; Huang, Huei-Ting; Lin, Hsin-Yi; Liu, Hsuan-Liang; Chang, Chih-Hung; Yang, Charng-Bin; Liu, Hwa-Chang

2007-06-01

441

An improved cryosection method for polyethylene glycol hydrogels used in tissue engineering.  

PubMed

The high water content of hydrogels allows these materials to closely mimic the native biological extracellular conditions, but it also makes difficult the histological preparation of hydrogel-based bioengineered tissue. Paraffin-embedding techniques require dehydration of hydrogels, resulting in substantial collapse and deformation, whereas cryosectioning is hampered by the formation of ice crystals within the hydrogel material. Here, we sought to develop a method to obtain good-quality cryosections for the microscopic evaluation of hydrogel-based tissue-engineered constructs, using polyethylene glycol (PEG) as a test hydrogel. Conventional sucrose solutions, which dehydrate cells while leaving extracellular water in place, produce a hydrogel block that is brittle and difficult to section. We therefore replaced sucrose with multiple protein-based and nonprotein-based solutions as cryoprotectants. Our analysis demonstrated that overnight incubation in bovine serum albumin (BSA), fetal bovine serum (FBS), polyvinyl alcohol (PVA), optimum cutting temperature (OCT) compound, and Fisher HistoPrep frozen tissue-embedding media work well to improve the cryosectioning of hydrogels. The protein-based solutions give background staining with routine hematoxylin and eosin, but the use of nonprotein-based solutions PVA and OCT reduces this background by 50%. These methods preserve the tissue architecture and cellular details with both in vitro PEG constructs and in constructs that have been implanted in vivo. This simple hydrogel cryosectioning technique improves the methodology for creation of good-quality histological sections from hydrogels in multiple applications. PMID:23448137

Ruan, Jia-Ling; Tulloch, Nathaniel L; Muskheli, Veronica; Genova, E Erin; Mariner, Peter D; Anseth, Kristi S; Murry, Charles E

2013-10-01

442

Coupling reaction and properties of poly(ethylene glycol)-linked phospholipases A2.  

PubMed

Secretory phospholipases A2 (PLA2) from Naja naja naja (cobra snake) venom, from Bothrops neuwiedii (crotalid snake) venom (two isoforms) and from bee venom were modified with tresylated monomethoxy poly(ethylene glycol) (TMPEG). The kinetic and inflammatory properties of the adducts (PEG-PLA2) were measured. As found by gel permeation chromatography, 95-100% of P-1 PLA2 from B. neuwiedii and PLA2 from N. naja naja venom change their chromatographic mobility after TMPEG treatment. By contrast, only 50-60% of both P-3-PLA2 from B. neuwiedii and PLA2 from bee venom modify their elution profile from Superdex 75. All the modified proteins preserved the enzymatic activity toward phospholipid monolayers, but with a reduced specific activity and greater lag times than the unmodified controls. These results suggest that the PEG-PLA2 complexes would have an altered interaction with lipid membranes. The PEG-linked proteins preserve their edema-inducing activity evaluated by the rat hind-paw edema test except for N. naja naja PEG-PLA2 in which inflammatory activity was significatively decreased. Altogether, the results show a partial dissociation of catalytic and inflammatory activities of Group II and III secretory PLA2s after their modification with PEG. PMID:12036042

Bianco, Ismael D; Daniele, José J; Delgado, Cristina; Fisher, Derek; Francis, Gillian E; Fidelio, Gerardo D

2002-04-01

443

Development of poly(ethylene glycol) conjugated lactoferrin for oral administration.  

PubMed

Lactoferrin (LF) is an iron-binding glycoprotein that possesses multifunctional biological activities. Recent reports from clinical trials suggest that LF is potentially effective as a therapeutic protein against cancer and gangrene. However, pharmaceutical proteins such as LF are unstable in vivo. Therefore, to improve stability, we developed mono-PEGylated bovine LF (20k-PEG-bLf) with branched 20 kDa (2 x 10 kDa) poly(ethylene glycol) (PEG). We examined in vitro activities such as iron binding, IL-6 cell based assay, and resistance to a proteolytic enzyme in artificial gastric fluid. The 20k-PEG-bLf protein was fully active in iron binding and exhibited 69.6 +/- 2.9% (mean +/- S.E., n = 6) of the original anti-inflammatory activity. The proteolytic half-life increased 2-fold over that of unmodified LF. In vivo pharmacokinetic analyses were performed to examine absorption from the intestinal epithelium and serum clearance. Direct administration of 20k-PEG-bLf (30 mg/kg) into rat stomachs demonstrated that the amount of absorption from the intestinal tract increased approximately 10-fold relative to unmodified LF. Intravenous injection of the protein (1 mg/kg) revealed that 20k-PEG-bLf prolongs serum half-life by approximately 5.4-fold, and that the area under the curve (AUC) was increased approximately 9.2-fold compared to that of unmodified LF. PEGylation improved the physical and pharmacokinetic properties of bovine LF. This is the first report on the use of bioconjugation of LF for the development of a promising oral pharmaceutical agent. PMID:18834167

Nojima, Yasuhiro; Suzuki, Yosuke; Iguchi, Kazuma; Shiga, Tuneo; Iwata, Aya; Fujimoto, Tomohito; Yoshida, Kazuhiro; Shimizu, Hirohiko; Takeuchi, Takashi; Sato, Atsushi

2008-11-19

444

Cancellous bone homograft storage with aluminium-polyethylene bags.  

PubMed

In order to transport and cryopreserve human tissues, it is essential to have an easy-to-use recipient where tissues can be kept in sterile conditions. Here we show the results obtained by using Macopharma's tissue freezing bags, an aluminium-polyethylene multilayer bag, in our tissue bank of the Centro Comunitario de Sangre y Tejidos de Asturias. Five hundred and twenty-seven cancellous bone homografts were obtained from hospitals located 120 km around our Bank. The homografts were submitted to bacteriological controls and sent to our bank in these bags. They were stored at -70 degrees C and sent in dry ice to about 50 hospitals, where the tissue was bacteriologically controlled and grafted. Furthermore, the behaviour of these bags at -140 degrees C (vapour nitrogen) or -196 degrees C (liquid nitrogen) was tested. Our results indicate that Macopharma aluminium-polyethylene bags are suitable for the transporting and cryopreserving of cancellous bone homografts. These bags could also be used for keeping tissues in nitrogen containers. PMID:16933042

Meana, A; Martinez, R; Cañal, P; Arriaga, M J; Román, F San; Llames, S; Orós, C; Moreno, A; Fernandez, C

2006-01-01

445

Nanomechanical measurements of polyethylene glycol hydrogels using atomic force microscopy.  

PubMed

Poly(ethylene glycol) (PEG)-based hydrogels are among the most widely used synthetic polymers for biomedical applications. Critical parameters of importance for PEG hydrogels are their mechanical properties which can be highly tuned. While properties such as elastic moduli have been measured at the bulk scale, it is often important to measure them at the micro and nanoscales. Further, non-destructive measurements of material properties can enable in situ and high-throughput monitoring for applications including modulating cellular interactions. In this research, the elastic modulus and the stiffness of polyethylene glycol diacrylate (PEG-DA) hydrogel matrices at the nanoscale are determined via nanoindentation using an atomic force microscope (AFM). The effect of varying parameters including monomer molecular weight, initiator concentration and rates of hydration on the mechanical strength of photopolymerized hydrogels were investigated. We present the effects of indentation parameters including loads and indent depths on such measurements. Mechanical characteristics of versatile PEG hydrogels can be adjusted based on polymer chain length and crosslinking, while completely hydrated hydrogels have mechanical properties similar to articular cartilage. A better understanding of these properties can enable tailoring hydrogel based biomaterials for various applications in scaffolds and tissue engineering. PMID:23237877

Drira, Zouheir; Yadavalli, Vamsi K

2013-02-01

446

Electrical properties of polyethylene highly filled with carbon  

SciTech Connect

Carbon-filled polyethylene composites were fabricated and tested to establish the practical lower limit of their electrical resistivity at room temperature and to investigate the trade-offs between low resistivity and the magnitude of the resistance anomaly (i.e., a large positive temperature coefficient of resistivity) that appears when such composites are heated through the polyethylene crystalline melting transition. Carbon blacks with large particle size and low surface area provided low-resistivity composites having large resistance anomalies. The largest resistance anomalies were found in composites that were well mixed, but the room-temperature resistivity also increased in composites that were cycled repetitively throught he crystalline-melting transition. A mixture of carbon blacks of two different sizes provided a lower resistance than was found in a material with the same fill of only the coarser black. By controlling the composition and the processing, composites were made with room-temperature resistivities lower than 0.2 ohm cm and resistance changes of at least 2 orders of magnitude. A resistance change of as much as 5 orders of magnitude was obtained for composites with room-temperature resistivities of only 1 ohm cm. {copyright} {ital 1996 Materials Research Society.}

Modine, F.A. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6030 (United States); Duggal, A.R. [General Electric Company, Corporate Research and Development, Schenectady, New York 12301 (United States); Robinson, D.N.; Churnetski, E.L. [Development Division, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee 37831-8095 (United States); Bartkowiak, M. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6030 (United States); Mahan, G.D. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6032 (United States)]|[Department of Physics, University of Tennessee, Knoxville, Tennessee 37996 (United States); Levinson, L.M. [General Electric Company, Corporate Research and Development, Schenectady, New York 12301 (United States)

1996-11-01

447

On the Structure of Holographic Polymer-dispersed Polyethylene Glycol  

SciTech Connect

Holographic polymerization (H-P) has been used to fabricate polymer-dispersed liquid crystals and pattern inert nanoparticles. In this article, one-dimensional grating structures of Norland resin and polyethylene glycol (PEG) were achieved using the H-P technique. Both reflection and transmission grating structures were fabricated. The optical properties of the reflection grating structures (also known as Bragg reflectors, BRs) are thermosensitive, which is attributed to the formation and crystallization of PEG crystals. The thermal switching temperature of the BR can be tuned by using different molecular weight PEG samples. The hierarchical structure and morphology of the BR were studied using synchrotron X-ray, polarized light microscopy and transmission electron microscopy. PEG crystals were found to be confined in {approx}60 nm thick layers in the BR. Upon crystallization, the PEG lamellae were parallel to the BR surfaces and PEG chains were parallel to the BR normal, resembling the confined crystallization behavior of polyethylene oxide (PEO) in PEO-block-polystyrene (PEO-b-PS) block copolymers. This observation suggests that the tethering effect in the block copolymer systems does not play a major role in PEG chain orientation in the confined nanoenvironment.

Birnkrant,M.; McWilliams, H.; Li, C.; Natarajan, L.; Tondiglia, V.; Sutherland, R.; Lloyd, P.; Bunning, T.

2006-01-01

448

Particle Size Control of Polyethylene Glycol Coated Fe Nanoparticles  

NASA Astrophysics Data System (ADS)

Recent interest in Fe nanoparticles with high magnetization is driven by their potential use in biomedical applications such as targeted drug delivery, MRI contrast enhancement and hyperthermia treatment of cancer. This study looks at the use of a polyethylene glycol (PEG) solution to mediate the particle size and therefore control the coercivity of the resulting nanoparticles. Iron nanoparticles were synthesized using an aqueous sodium borohydride reduction of ferrous chloride by a simultaneous introduction of reagents in a Y- junction. The resulting product was collected in a vessel containing a 15 mg/ml carboxyl terminated polyethylene glycol (cPEG) in ethyl alcohol solution located under the Y junction. By varying the length of tubing below the Y junction, the particle size was varied from 5-25 nm. X-ray diffraction data indicates the presence of either amorphous Fe-B or crystalline alpha Fe, depending on the molar ratio of reagents. Magnetic measurements indicate the particles are ferromagnetic with values of coercivity ranging from 200-500 Oe and a saturation magnetization in range of 70-110 emu/g. The XRD shows that the particles are not affected by the polymer coating.

Srinivasan, B.; Bonder, M. J.; Zhang, Y.; Gallo, D.; Hadjipanayis, G. C.

2006-03-01

449

Synthesis of Poly(ethylene oxide) Approaching Monodispersity.  

PubMed

Polydispersity in polymers hinders fundamental understanding of their structure-property relationships and prevents them from being used in fields like medicine, where polydispersity affects biological activity. The polydispersity of relatively short-chain poly(ethylene oxide) [(CH2 CH2 O2 )n ; PEO] affects its biological activity, for example, the toxicity and efficacy of PEOylated drugs. As a result, there have been intensive efforts to reduce the dispersity as much as possible (truly monodispersed materials are not possible). Here we report a synthetic procedure that leads to an unprecedented low level of dispersity. We also show for the first time that it is possible to discriminate between PEOs differing in only 1 ethylene oxide (EO) unit, essential in order to verify the exceptionally low levels of dispersity achieved here. It is anticipated that the synthesis of poly(ethylene oxide) approaching monodispersity will be of value in many fields where the applications are sensitive to the distribution of molar mass. PMID:24828235

Maranski, Krzysztof; Andreev, Yuri G; Bruce, Peter G

2014-06-16

450

Effect of modification on the structure and and mechanical properties of chlorosulfonated polyethylene films  

Microsoft Academic Search

Structure formation in chlorosulfonated polyethylene films is described. Modification with phenol-formaldehyde resin leads to a change in the supermolecular structures, which are stabilized by introducing 1% aluminum diisobutoxymonoacetoacetate into the system. It is shown that modifying the chlorosulfonated polyethylene leads to the formation of stable supermolecular structures and a considerable improvement in the mechanical properties of the films.

M. I. Karyakina; S. M. Lavendele; N. V. Maiorova; Z. Ya. Berestneva; V. A. Kargin

1969-01-01

451

Combined heparin and polyethylene oxide surface modification for improved blood compatibility  

Microsoft Academic Search

The main objective of this work was to develop a new method for the modification of polymer surfaces with the aim of improving the biocompatibility of the materials, and to gain an improved understanding of surface-blood interactions. ^ Low density polyethylene was chosen as a substrate for the studies. Polyethylene substrates were first aminated by plasma polymerization of allylamine using

Zhanxu Jia

2006-01-01

452

Wear behaviour of cross-linked polyethylene assessed in vitro under severe conditions  

Microsoft Academic Search

The polyethylene (PE) for hip implants presents serious clinical problems; the production of debris may induce adverse tissue reactions that may lead to extensive bone loss around the implant and consequently osteolysis and implant loosening. Several attempts have been made to improve the wear properties of ultra-high molecular weight polyethylene (UHMWPE). More recently the attention of various researchers has been

Saverio Affatato; Gianluca Bersaglia; Mirko Rocchi; Paola Taddei; Concezio Fagnano; Aldo Toni

2005-01-01

453

Early Failure of a Polyethylene Acetabular Liner Cemented Into a Metal Cup  

Microsoft Academic Search

In 2002, a patient underwent revision total hip arthroplasty for polyethylene wear. The acetabular cup was well fixed, and it was decided to cement a new polyethylene liner into the existing cup. In 2006, the patient presented with inability to weight bear and easy subluxation of the hip. Revision surgery was performed, and all components were examined postoperatively. Investigation with

David A. J. Wilson; Joseph P. Corkum; Matthew G. Teeter; David W. Holdsworth; Michael J. Dunbar

454

Evaluation of polyethylene terephthalate cyclic trimer migration from microwave food packaging using temperature?time profiles  

Microsoft Academic Search

The polymer polyethylene terephthalate (PET) is widely used for packaging food that will be heated or cooked in the PET container. A procedure was developed to predict the potential of PET to migrate from the container into the food. Migration experiments using crystallized polyethylene terephthalate (CPET) and corn oil were performed at 115, 146 and 176°C. From these experiments diffusion

T. H. Begley; H. C. Hollifield

1990-01-01

455

Biocompatibility of polyethylene terephthalate (Trevira ® hochfest) augmentation device in repair of the anterior cruciate ligament  

Microsoft Academic Search

The biocompatibility of a 3mm band made of polyethylene terephthalate (Trevira® hochfest) has been tested in an experimental study within right knee joints of 60 sheep. After transsecting the anterior cruciate ligament (ACL), two randomized groups were formed. In group I, the ACL was repaired according to the Marshall technique whilst in group II an additional 3mm polyethylene terephthalate (PET)

Helmut Seitz; Stefan Marlovits; Ilse Schwendenwein; Elisabeth Müller; Vilmos Vécsei

1998-01-01

456

Impact fatigue response of ultra-high molecular weight linear polyethylene  

Microsoft Academic Search

The impact fatigue response of ultra-high molecular weight linear polyethylene (UHMW LPE), in a special test, has been examined and the results are presented in this paper. In an attempt to understand the influence of high molecular weight on impact strength, identical measurements were made on a normal molecular weight linear polyethylene (NMW LPE). UHMW LPE is found to have

S. K. Bhateja; J. K. Rieke; E. H. Andrews

1979-01-01

457

A calorimetric study of normal high density and ultra-high molecular weight polyethylene blends  

Microsoft Academic Search

The melting and the crystallization of blends of ultra-high molecular weight polyethylene (UHMWPE) and polyethylene high density with normal molecular weight (NMWPE) are investigated by means of differential scanning calorimetry (DSC). Mixing the components at a temperature below the flow temperature of UHMWPE (215 °C) results in segregated melting and crystallization. The segregated melting and crystallization temperatures of both components

L. Minkova; M. Mihailov

1987-01-01

458

Degradation diagnosis of ultra-high-molecular weight polyethylene (UHMWPE) by terahertz-time-domain spectroscopy  

Microsoft Academic Search

We present that degradation of ultra-high-molecular-weight-polyethylene induces drastic absorption-increase ranging continuously over the THz region. This demonstrates the possibility that THz-TDS is applied to quality-control of ultra-high-molecular-weight polyethylene, which is widely utilized in medical implants.

K. Yamamoto; M. Yamagiichi; M. Tani; M. Hangyo; S. Teramura; T. Isu; N. Toraita

2004-01-01

459

High-Speed Spinning of Ultra-High Molecular Weight Polyethylene Fibres.  

National Technical Information Service (NTIS)

The aim of the thesis is to study and optimize the oriented crystallization of the ultra-high molecular weight polyethylene in the spinline, at high winding speeds, and obtain a strong polyethylene fibre in a one step process. Many variables influence the...

M. Roukema

1991-01-01

460

A comparative study of the wettability of steel, carbon, and polyethylene fibers by water  

Microsoft Academic Search

The wettability of fibers by water was found to increase in this order: polyethylene fiber, steel fiber, and carbon fiber. The order applies whether the fibers were surface-treated or not. Treatment with ozone was effective for improving the wettability of carbon and steel fibers. Treatment with acetone was effective for steel and polyethylene fibers. Treatments with HCl and NaOH were

W. Lu; X. Fu; D. D. L. Chung

1998-01-01

461

Process for Preparing Radiation Stabilized Polyethylene and Food Package Utilizing Same.  

National Technical Information Service (NTIS)

The addition of a minor amount of 2,2'-methylene-bis(4-ehtyl-6-t-butyl alcohol) to polyethylene stabilizes the polyethylene so that when subjected to high energy ionizing radiation in the food sterilization dose range and even higher there is no odor form...

H. N. Schlein B. R. La Liberte

1965-01-01

462

High-temperature tensometry and its application to amorphous polyethylene terephthalate  

Microsoft Academic Search

Amorphous polyethylene terephthalate will crystallize at elevated temperatures either by the action of the temperature alone or as a result of a stretching process. An apparatus has been constructed by means of which the stress-strain curves of amorphous polyethylene terephthalate in the rubber-like state may be investigated under conditions where the material is heated for a period of not more

E. L. Foster; H. Heap

1957-01-01

463

The influence of soil macroinvertebrates on primary biodegradation of starch-containing polyethylene films  

Microsoft Academic Search

The primary biodegradability of polyethylene (PE) films containing different percentages of cornstarch (0–50%) and other additives (prooxidant, oxidized polyethylene) was tested using four species of earthworms (Eisenia fetida, Lumbricus terrestris, Aporectodea trapezoides, Aporectodea tuberculata), three species of cockroaches (Periplaneta americana, Blaberus sp.,Blattella germanica), termites (Reticulotermes flavipes), sowbugs (Porcellio laevis), and crickets (Acheta domesticus). These studies were conducted to elucidate the

Rong Tsao; Todd A. Anderson; Joel R. Coats

1993-01-01

464

Demonstration of polyscann ultrasonic butt-fusion inspection system for polyethylene pipes  

Microsoft Academic Search

The demonstration of the Polyscann Ultrasonic Butt-Fusion Inspection System and laboratory research into its effectiveness as a quality control tool for installation of polyethylene pipe are described. In the demonstration, conducted at North Fort Hood, TX, 13 sections of 8 in. diameter polyethylene pipe were assembled and tied into a previously installed 8 in. gas pipeline. The system was successfully

Orange S. Marshall Jr.; James B. Hunt

1993-01-01

465

Deterioration of Water-Immersed Polyethylene-Coated Wire by Treeing  

Microsoft Academic Search

Although some reports of the water-resisting life of polyethylene-insulated wires have been made, studies of mechanism of the deterioration phenomenon have been scarcely reported. In this paper, it is pointed out that a major cause of the deterioration of polyethylene-coated wire in water is the occurrence of the \\

Takao Miyashita

1971-01-01

466

Meta-analysis and cost comparison of polyethylene glycol lavage versus sodium phosphate for colonoscopy preparation  

Microsoft Academic Search

Background: Although polyethylene glycol lavage solutions are widely used for colonoscopy preparation, evidence suggests that sodium phosphate is better tolerated and has similar efficacy. The purpose of this study was to compare compliance with and efficacy of polyethylene glycol and sodium phosphate using meta-analysis and to compare the cost of colonoscopy with both methods. Methods: We used Medline to identify

Chia-Wen Hsu; Thomas F. Imperiale

1998-01-01

467

Pecularities of the thermomechanical behaviour of ultra-high molecular weight linear polyethylene and its blends with linear polyethylene of normal molecular weight  

Microsoft Academic Search

Ultra-high molecular weight polyethylene UHMWPE (Mw=4 · 106,Is=O g\\/ 10 min), high density polyethylene of normal molecular weight NMWPE (Is= 4.8 g\\/10 min) and their blends have been investigated by means of thermomechanical loading in constant and impulse regime. It has been established that after melting, NMWPE passes to a viscous-liquid state. After melting at 138 °C UHMWPE passes to

M. Mihailov; L. Minkova

1987-01-01

468

Ultra-drawing of low molecular weight polyethylene — ultra-high molecular weight polyethylene blend films prepared by gelation\\/crystallization from semi-dilute solutions  

Microsoft Academic Search

Greatest drawability was studied for blend films with branched low molecular weight polyethylene (B-LMWPE) and ultra-high molecular weight polyethylene (UHMWPE) prepared by gelation\\/crystallization from solutions. The morphology of B-LMWPE–UHMWPE dry gel film and its deformation mechanism were mainly estimated by using differential scanning calorimeter, small-angle X-ray scattering, wide-angle X-ray diffraction and solid-state 13C NMR. The detailed analysis was carried out

Yuezhen Bin; Lin Ma; Reiko Adachi; Hiromichi Kurosu; Masaru Matsuo

2001-01-01

469

Macromolecular Nanotechnology Intercalated linear low density polyethylene (LLDPE)\\/clay nanocomposites prepared with oxidized polyethylene as a new type compatibilizer: Structural, mechanical and barrier properties  

Microsoft Academic Search

In this study, the use of low molecular weight oxidized polyethylenes (OxPE) with different molecular weight and acid number as a new type of compatibilizer in low density polyethylene (LLDPE)\\/org-clay nanocomposite preparation was examined. Nanocomposites having 5 phr (part per hundred) org-clay were prepared by melt processing. The effect of com- patibilizer polarity and clay dispersion on the thermal, mechanical

Ali Durmus; Maybelle Woo; Ahmet Kasgoz; Christopher W. Macosko; Michael Tsapatsis

470

Mechanical properties and structure of glassy and semicrystalline random copolymers of poly(ethylene terephthalate) and poly(ethylene naphthalene-2,6-dicarboxilate)  

Microsoft Academic Search

The microhardness,H, of random copolymers of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalene-2,6-dicarboxilate) (PEN) was determined over a wide range of compositions. It is shown that microhardness of the materials is strongly affected by the composition. The mechanical property,H, of the quenched amorphous copolyester films is discussed in terms of a simple model given by the additivity values of the single

C. Santa Cruz; F. J. Baltá Calleja; H. G. Zachmann; D. Chen

1992-01-01

471

Diffraction study of crystalline structure of random copolymers of poly(ethylene terephthalate) and poly(ethylene naphthalene-2,6-dicarboxylate)  

Microsoft Academic Search

A recent study has indicated that random copolymers of poly(ethylene terephthalate) and poly(ethylene naphthalene-2,6-dicarboxylate) (PET\\/PEN) can crystallize over the full composition range under the condition of hot-drawing, and that the crystallites formed are based on random sequences of PET and PEN units. This paper is an extension of this study. Wide-angle fibre X-ray diffraction patterns from PET\\/PEN random copolymers have

X. Lu; A. H. Windle

1996-01-01

472

Studies of miscibility, transesterification and crystallization in blends of poly(ethylene terephthalate) and Poly(ethylene-2,6-naphthalene dicarboxylate)  

Microsoft Academic Search

Blends of poly(ethylene terephthalate) (PET) and poly(ethylene-2,6-naphthalene dicarboxylate) (PEN) were obtained by coprecipitation from solution followed by melt-pressing for different timestmand quenching in iced water. When the melt-pressing time was 0.2 and 0.5 min, two glass transition temperaturesTgwere observed by means of dynamic mechanical analysis (DMA), indicating that there are two phases present, a PEN-rich phase and a PET-rich phase.

E. Andresen; H. G. Zachmann

1994-01-01

473

Moisture barrier of Al x O y coating on poly(ethylene terephthalate), poly(ethylene naphthalate) and poly(carbonate) substrates  

Microsoft Academic Search

The moisture barrier property of AlxOy coated poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN) and poly(carbonate) (PC), have been investigated. The differences in the morphology of the AlxOy sputtered grown on these substrate were investigated using atomic force microscopy (AFM). The initial growth of the AlxOy followed closely the topology of the substrate and an amplified roughness was observed. In the

Hongyee Low; Yongan Xu

2005-01-01

474

Poly-DL-lactic acid: Polyethylene glycol block copolymers. The influence of polyethylene glycol on the degradation of poly-DL-lactic acid  

Microsoft Academic Search

ABA block copolymers of polyethylene glycol and poly-DL-lactic acid were prepared by ring-opening polymerization of DL-dilactide with ?,?-dihydroxy polyethylene glycol, n, 1000 or 2000. The morphology of the resulting copolymers, with PEG : PLA ratios(mol\\/mol) of 1:2, 1: 3 and 1:4, was characterized by DSC and ESR spectroscopy. The rate of water uptake was biphasic, reflecting the contribution of two

S. S. Shah; K. J. Zhu; C. G. Pitt

1994-01-01

475

76 FR 45508 - Polyethylene Terephthalate Film, Sheet and Strip From the United Arab Emirates: Extension of Time...  

Federal Register 2010, 2011, 2012, 2013

...Polyethylene Terephthalate Film, Sheet and Strip From the United Arab Emirates: Extension of Time Limit for Preliminary Results of Antidumping...polyethylene terephthalate film, sheet and strip from the United Arab Emirates (UAE) for the period November 01, 2009, through...

2011-07-29

476

75 FR 76954 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Extension of Time Limit for Final...  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Extension...the preliminary results of this review. See Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan:...

2010-12-10

477

Polyethylene encapsulatin of nitrate salt wastes: Waste form stability, process scale-up, and economics. Technology Status Topical Report.  

National Technical Information Service (NTIS)

A polyethylene encapsulation system for treatment of low-level radioactive, hazardous, and mixed wastes has been developed at Brookhaven National Laboratory. Polyethylene has several advantages compared with conventional solidification/stabilization mater...

P. D. Kalb J. H. Heiser P. Colombo

1991-01-01

478

Method for Shaping Polyethylene Tubing: An insulated copper wire is inserted and bent, then heat is applied.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A new method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stainless-...

1981-01-01

479

Effect of chain architecture on the compression behavior of nanoscale polyethylene particles  

PubMed Central

Polymeric particles with controlled internal molecular architectures play an important role as constituents in many composite materials for a number of emerging applications. In this study, classical molecular dynamics techniques are employed to predict the effect of chain architecture on the compression behavior of nanoscale polyethylene particles subjected to simulated flat-punch testing. Cross-linked, branched, and linear polyethylene chain architectures are each studied in the simulations. Results indicate that chain architecture has a significant influence on the mechanical properties of polyethylene nanoparticles, with the network configuration exhibiting higher compressive strengths than the branched and linear architectures. These findings are verified with simulations of bulk polyethylene. The compressive stress versus strain profiles of particles show four distinct regimes, differing with that of experimental micron-sized particles. The results of this study indicate that the mechanical response of polyethylene nanoparticles can be custom-tailored for specific applications by changing the molecular architecture.

2013-01-01

480

Effect of chain architecture on the compression behavior of nanoscale polyethylene particles  

NASA Astrophysics Data System (ADS)

Polymeric particles with controlled internal molecular architectures play an important role as constituents in many composite materials for a number of emerging applications. In this study, classical molecular dynamics techniques are employed to predict the effect of chain architecture on the compression behavior of nanoscale polyethylene particles subjected to simulated flat-punch testing. Cross-linked, branched, and linear polyethylene chain architectures are each studied in the simulations. Results indicate that chain architecture has a significant influence on the mechanical properties of polyethylene nanoparticles, with the network configuration exhibiting higher compressive strengths than the branched and linear architectures. These findings are verified with simulations of bulk polyethylene. The compressive stress versus strain profiles of particles show four distinct regimes, differing with that of experimental micron-sized particles. The results of this study indicate that the mechanical response of polyethylene nanoparticles can be custom-tailored for specific applications by changing the molecular architecture.

Wu, Jianyang; He, Jianying; Odegard, Gregory M.; Zhang, Zhiliang

2013-07-01

481

Nd:Yag laser irradiation of single lap joints made by polyethylene and polyethylene doped by carbon nanomaterials  

NASA Astrophysics Data System (ADS)

Thermoplastic polyethylene can be welded by the transmission laser welding technique (TTLW) that exhibits some process related benefits with respect other conventional joining methods. This justifies its large use in wide fields, from the automotive to medical or domestic appliances. In this research, we studied single lap joints made by polyethylene pure and filled with carbon nanomaterials (0.2% in weight) to make the polymer laser absorbent. The joints were irradiated by a Nd:YAG laser operating at 1064 nm (first harmonic) with an intensity of 107 W/cm2 and 1 ÷ 30Hz, a maximum pulse energy of 300mJ and a laser spot of ? 1 cm2 (no focusing lens were employed). The joints were characterized by morphological analysis, mechanical shear tests and calorimetric analysis. The results suggested that the laser exposition time must be opportunely balanced in order to avoid a poor adhesion between the polymer sheets and to realized efficient joints. In particular the mechanical test showed that the laser exposition time of 40 seconds is the best conditions to obtain the highest shear strength of the joints of 140 N. After too prolonged laser exposure times, degrading phenomena starts.

Visco, A. M.; Brancato, V.; Cutroneo, M.; Torrisi, L.

2014-04-01

482

Cross-linked Compared with Historical Polyethylene in THA: An 8-year Clinical Study  

PubMed Central

Wear particle-induced osteolysis is a major cause of aseptic loosening in THA. Increasing wear resistance of polyethylene (PE) occurs by increasing the cross-link density and early reports document low wear rates with such implants. To confirm longer-term reductions in wear we compared cross-linked polyethylene (irradiation in nitrogen, annealing) with historical polyethylene (irradiation in air) in a prospective, randomized clinical study involving 48 patients who underwent THAs with a minimum followup of 7 years (mean, 8 years; range, 7–9 years). The insert material was the only variable. The Harris hip score, radiographic signs of osteolysis, and polyethylene wear were recorded annually. Twenty-three historical and 17 moderately cross-linked polyethylene inserts were analyzed (five patients died, three were lost to followup). At 8 years, the wear rate was lower for cross-linked polyethylene (0.088 ± 0.03 mm/year) than for the historical polyethylene (0.142 ± 0.07 mm/year). This reduction (38%) did not diminish with time (33% at 5 years). Acetabular cyst formation was less frequent (39% versus 12%), affected fewer DeLee and Charnley zones (17% versus 4%), and was less severe for the cross-linked polyethylene. The only revision was for an aseptically loose cup in the historical polyethylene group. Moderately cross-linked polyethylene maintained its wear advantage with time and produced less osteolysis, showing no signs of aging at mid-term followup. Level of Evidence: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Grimm, Bernd; Vencken, Wendy; Heyligers, Ide C.; Tonino, Alphons J.

2008-01-01

483

Migration studies of 3-chloro-1,2-propanediol (3-MCPD) in polyethylene extrusion-coated paperboard food packaging.  

PubMed

The manufacturing process of paperboard food packaging can produce small quantities of 3-chloro-1,2-propanediol (3-MCPD or 3-monochloropropane-1,2-diol) when wet-strength resins containing epichlorohydrin are used. 3-MCPD is from the same family as 1,3-dichloro-2-propanol (1,3-DCP), which is known to cause cancer in animals. 3-MCPD has been found in acid hydrolyzed vegetable protein, Asian sauces and paperboard for food contact. In this investigation, we conducted extraction studies to measure 3-MCPD migration into food simulant solvents from the food contact side of polyethylene extrusion-coated paperboard beverage cartons and aqueous extractions of cut pieces from the entire paperboard. We demonstrate that 3-MCPD confirmed present at concentrations up to 9.9 mg kg(-1) within the paperboard matrix does not migrate through the polyethylene-coated food contact surface. The aqueous extraction of the entire paperboard and food contact side extractions with aqueous/acidic food simulants were performed using US Food and Drug Administration (FDA) and European Commission (EU) migration testing protocols. We also show that no significant amount of 3-MCPD migrates through the unskived edges on the inside seam of the paperboard structure. The methodology for the aqueous and migration cell extractions using GC-MS analyses was validated with a limit of quantification (LOQ) of 0.009 mg kg(-1) and a limit of detection (LOD) of 0.005 mg kg(-1). PMID:20486004

Pace, Gregory V; Hartman, Thomas G

2010-06-01

484

Elaboration et caracterisation de nanocomposites polyethylene/montmorillonite  

NASA Astrophysics Data System (ADS)

This research project consists in preparing polyethylene/montmorillonite nanocomposites for film packaging applications. Montmorillonite is a natural clay with an exceptional aspect ratio. In recent years, its incorporation in polymer matrices has attracted great interest. The pioneer work from Toyota on polyamide-6/montmorillonite composites has shown that it was possible to disperse the clay at a nanometric scale. Such a structure, so-called exfoliated, leads to a significant increase in mechanical, barrier and fire retardant properties, even at low volumetric fractions of clay. This allows a valorization of the polymeric material at moderate cost. Due to its high polarity, montmorilloite exfoliation in polymeric matrices is problematic. In the particular case of polyolefin matrices, the platelets dispersion remains limited: most frequently, the composites obtained exhibit conventional structures (microcomposites) or intercalated structures. To solve this problem, two techniques are commonly employed: the surface treatment of the clay, which allows the expansion of the interfoliar gallery while increasing the affinity between the clay and the polymer, and the use of a polar compatibilizing agent (grafted polyolefin). The first part of this thesis deals with the preparation and the characterization of highly thermally stable organophilic montmorillonites. Commercial organophilic montmorillonites are treated with quaternary ammonium intercalating agents. However, those intercalating agents present a poor thermal stability and are susceptible to decompose upon processing, thu