Note: This page contains sample records for the topic polyethylene glycol-modified proteins from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Antibodies against Polyethylene Glycol Produced in Animals by Immunization with Monomethoxy Polyethylene Glycol Modified Proteins  

Microsoft Academic Search

Antibodies to polyethylene glycol (PEG) were raised in rabbits by immunization with monomethoxy polyethylene glycol modified ovalbumin (OA), bovine superoxide dismutase (SOD), and ragweed pollen extract (Rag), given in Freund’s complete adjuvant (FCA). Immunogenicity depended on the nature of the protein and the degree of modification. With modified OA, in the presence of FCA, the majority of animals showed an

Ary Wolfgang Richter; Eva Ĺkerblom

1983-01-01

2

Ethanol-sodium chloride-phosphate mobile phase for size-exclusion chromatography of poly(ethylene glycol) modified proteins  

Microsoft Academic Search

The use of an aqueous sodium chloride-phosphate mobile phase for size-exclusion chromatography of poly(ethylene glycol) modified (PEGylated) proteins resulted in premature degradation of silica-based gel filtration columns. This column degradation was manifested as peak tailing and loss of resolution. An aqueous ethanol-sodium chloride-phosphate mobile phase was identified which extended column lifetimes without loss of resolution or change in peak shape.

Joseph J. Ratto; Sheila R. O'Conner; Adrian R. Distler; Gay-May Wu; David Hummel; Michael J. Treuheit; Alan C. Herman; Janice M. Davis

1997-01-01

3

Characterization of Polyethylene Glycol Modified Hemoglobins  

NASA Astrophysics Data System (ADS)

Polyethylene glycol modified hemoglobins (PEGHbs) was characterized by liquid chromatography and fluorescence methods. We prepared four samples of two different molecular weight PEG, 5KDa and 20KDa, modified bovine and human hemoglobin. We studied the oxygen affinities, stabilities, and peroxidase activities of PEGHbs. We have related oxygen affinities with different degrees of modifications. The data showed that the modification on the beta subunits was less stable than that of the alpha subunits on the human Hb based samples especially. We also compared peroxidase activities among different modified PEGHbs.

Salazar, Gil; Barr, James; Morgan, Wayne; Ma, Li

2011-03-01

4

Capillary electrophoretic separation of high-molecular-weight poly(ethylene glycol)-modified proteins.  

PubMed

This study was designed to demonstrate the utility of capillary electrophoresis (CE) for separating high-molecular-weight poly(ethylene glycol) (PEG)-conjugated proteins. As a CE method, sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) was applied to analyze interferon alpha (IFN) modified with branched and trimer-structured PEG molecules. Five mono-PEG-IFN conjugates prepared with two branched PEGs (MW 20 and 40 kDa) and three trimer-structured PEGs (MW 23.5, 43.5, and 47 kDa) were purified by cation-exchange chromatography and their masses were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The SDS-CGE method showed high separation capacity by differentiating PEG-IFN conjugates with small differences in molecular size, such as PEG(40K)-, PEG(43.5K)-, and PEG(47K)-IFNs, and it was useful for checking the purity of each mono-PEG-IFN. This study shows that SDS-CGE can well be utilized in the development and quality control of PEGylated proteins prepared with various types of PEG. PMID:17888863

Na, Dong Hee; Park, Eun Ji; Jo, Yeong Woo; Lee, Kang Choon

2007-08-15

5

Structure of poly(ethylene glycol)-modified horseradish peroxidase in organic solvents: infrared amide I spectral changes upon protein dehydration are largely caused by protein structural changes and not by water removal per se.  

PubMed

Fourier transform infrared (FTIR) spectroscopy has emerged as a powerful tool to guide the development of stable lyophilized protein formulations by providing information on the structure of proteins in amorphous solids. The underlying assumption is that IR spectral changes in the amide I and III region upon protein dehydration are caused by protein structural changes. However, it has been claimed that amide I IR spectral changes could be the result of water removal per se. Here, we investigated whether such claims hold true. The structure of horseradish peroxidase (HRP) and poly(ethylene glycol)-modified HRP (HRP-PEG) has been investigated under various conditions (in aqueous solution, the amorphous dehydrated state, and dissolved/suspended in toluene and benzene) by UV-visible (UV-Vis), FTIR, and resonance Raman spectroscopy. The resonance Raman and UV-Vis spectra of dehydrated HRP-PEG dissolved in neat toluene or benzene were very similar to that of HRP in aqueous buffer, and thus the heme environment (heme iron spin, coordination, and redox state) was essentially the same under both conditions. Therefore, the three-dimensional structure of HRP-PEG dissolved in benzene and toluene was similar to that in aqueous solution. The amide I IR spectra of HRP-PEG in aqueous buffer and of dehydrated HRP-PEG dissolved in neat benzene and toluene were also very similar, and the secondary structure compositions (percentages of alpha-helices and beta-sheets) were within the standard error the same. These results are irreconcilable with recent claims that water removal per se could cause substantial amide I IR spectral changes (M. van de Weert, P.I. Haris, W.E. Hennink, and D.J. Crommelin. 2001. Anal. Biochem. 297:160-169). On the contrary, amide I IR spectral changes upon protein dehydration are caused by perturbations in the secondary structure. PMID:12496131

Al-Azzam, Wasfi; Pastrana, Emil A; Ferrer, Yancy; Huang, Qing; Schweitzer-Stenner, Reinhard; Griebenow, Kai

2002-12-01

6

Polyphenylene Ether\\/Glycol Modified Polyethylene Terephthalate Blends and their Physical Characteristics  

Microsoft Academic Search

Polyphenylene ether (PPE)\\/glycol modified polyethylene terephthalate (PETG) blends with various compositions were fabricated via a melt blending method using a laboratory-scale twin-screw extruder. The fracture surface morphology of the PPE\\/ PETG blends was examined by scanning electron microscopy (SEM) and, based on its data, it was observed that PPE and PETG are immiscible. Thermal stability and mechanical properties of the

In Gu Kim; Sun Young Hong; Byung O Park; Hyoung Jin Choi; Jae Heung Lee

2012-01-01

7

Polyphenylene Ether\\/Glycol Modified Polyethylene Terephthalate Blends and their Physical Characteristics  

Microsoft Academic Search

Polyphenylene ether (PPE)\\/glycol modified polyethylene terephthalate (PETG) blends with various compositions were fabricated via a melt blending method using a laboratory-scale twin-screw extruder. The fracture surface morphology of the PPE\\/PETG blends was examined by scanning electron microscopy and, based on its data, it was found that PPE and PETG are immiscible. Thermal stability and mechanical properties of the blends were

IN GU KIM; SUN YOUNG HONG; BYUNG O PARK; HYOUNG JIN CHOI; JAE HEUNG LEE

2011-01-01

8

Polyethylene glycol-modified enzymes trap water on their surface and exert enzymic activity in organic solvents  

Microsoft Academic Search

Polyethylene glycol-modified enzymes dissolved and had high enzymic activity in organic solvents. A trace amount of water was found to be necessary for the activity. It was reasoned that the amphipathic polymer covalently attached to enzymes kept water molecules around them. This was supported by findings that : (1) high enzymic activity was found in water- immiscible solvents, whereas activity

K. Takahashi; H. Nishimura; T. Yoshimoto; M. Okada; A. Ajima; A. Matsushima; Y. Tamaura; Y. Saito; Y. Inada

1984-01-01

9

Polyethylene glycol modified FGF21 engineered to maximize potency and minimize vacuole formation  

Microsoft Academic Search

Fibroblast growth factor 21 (FGF21) is involved in regulating energy metabolism, and it has shown significant promise as a treatment for type II diabetes; however, the native protein has a very short circulating half-life necessitating frequent injections to maintain a physiological effect. Polyethylene glycol (PEG) conjugation to proteins has been used as a method for extending the circulating half-life of

J. Xu; J. Bussiere; J. Yie; A. Sickmier; P. An; E. Belouski; S. Stanislaus; K. W. Walker

2013-01-01

10

Carbohydrate-specifically polyethylene glycol-modified ricin A-chain with improved therapeutic potential  

Microsoft Academic Search

Ricin A-chain, which exhibits excellent cytotoxicity to tumor cells, has been widely used as an immunotoxin source. However, it has the fatal shortcoming of poor pharmacokinetics due to the tremendous liver uptake via carbohydrate-mediated recognition. Modification of proteins with polyethylene glycol, PEGylation, has the advantages of shielding the specific sites and prolonging the biological half-life. In this study, the carbohydrate-specific

Yu Seok Youn; Dong Hee Na; Sun Dong Yoo; Soo-Chang Song; Kang Choon Lee

2005-01-01

11

Polyethylene glycol modified FGF21 engineered to maximize potency and minimize vacuole formation.  

PubMed

Fibroblast growth factor 21 (FGF21) is involved in regulating energy metabolism, and it has shown significant promise as a treatment for type II diabetes; however, the native protein has a very short circulating half-life necessitating frequent injections to maintain a physiological effect. Polyethylene glycol (PEG) conjugation to proteins has been used as a method for extending the circulating half-life of many pharmaceutical proteins; however, PEG does carry the risk of vacuole formation, particularly in the renal tubular epithelium. Since renal vacuole formation may be particularly problematic for diabetic patients, we engineered site-directed PEGylated variants of FGF21 with sustained potency and minimized vacuole formation. This was accomplished both by probing the site of PEGylation on FGF21 as well as by examining various PEG configurations. While the site of PEGylation has a significant impact on the bioactivity of FGF21, it has only a marginal impact on vacuole formation; however, the configuration and number of PEGs conjugated to the protein has a much more profound effect on vacuologenesis. PMID:23594041

Xu, Jing; Bussiere, Jeanine; Yie, Junming; Sickmier, Allen; An, Phil; Belouski, Ed; Stanislaus, Shanaka; Walker, Kenneth W

2013-05-09

12

Efficient inhibition of hepatitis B virus replication in vivo, using polyethylene glycol-modified adenovirus vectors.  

PubMed

Achieving safe delivery of anti-hepatitis B virus (HBV) RNA interference (RNAi) effectors is an important objective of this gene-silencing technology. Adenoviruses (Ads) have a natural tropism for the liver after systemic administration, and are useful for delivery of expressed anti-HBV RNAi sequences. However, a drawback of Ad vectors is diminished efficacy and toxicity that results from stimulation of innate and adaptive immunity. To attenuate these effects we used monomethoxy polyethylene glycol-succinimidyl propionate (mPEG-SPA) to modify first-generation vectors that express an anti-HBV RNAi effector. Efficient hepatocyte transduction and knockdown of HBV replication were achieved after intravenous administration of 5 x 10(9) PEGylated or native recombinant Ads to HBV transgenic mice. After the first injection, circulating HBV viral particle equivalents (VPEs) remained low for 3 weeks and began to increase after 5 weeks. A second dose of PEGylated anti-HBV Ad caused a less sustained decrease in circulating VPEs, but no silencing after a second dose was observed in animals treated with unmodified vector. Release of inflammatory cytokines, including monocyte chemoattractant protein-1 (MCP-1), interferon-gamma, interleukin-6, and tumor necrosis factor-alpha, was elevated in animals receiving unmodified vectors. However, only a modest increase in MCP-1 was observed in mice that received a second dose of PEG Ads. Also, polymer-conjugated vectors induced a weaker adaptive immune response and were less hepatotoxic than their unmodified counterparts. Collectively, these observations show that PEG modification of Ads expressing RNAi effectors improves their potential for therapeutic application against HBV infection. PMID:19848584

Crowther, Carol; Ely, Abdullah; Hornby, Judith; Mufamadi, Steven; Salazar, Felix; Marion, Patricia; Arbuthnot, Patrick

2008-11-01

13

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

2012-07-02

14

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

SciTech Connect

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 modified enzyme retained 100% of its activity in aqueous solutions and showed enhanced tolerance against the organic solvent. The activity of the modified enzyme was found to be over twice that of the native enzyme in the presence of 10% (v/v) MeCN. The solubility of PCP was enhanced significantly by the addition of MeCN to aqueous solutions, such that it was over 10-fold more soluble in the presence of 15% (v/v) MeCN than in pure aqueous buffer solution. Capitalizing on the enhanced substrate solubility and the increased activity of the modified enzyme, the catalytic efficiency of the modified LiP in solutions containing 15% MeCN was over 11-fold higher than that of the native enzyme in buffer solutions in unoptimized reactor systems. Continued research both in the use of organic solvents to increase the availability of recalcitrant contaminants and in the modification of enzymes to enhance their activity and stability in such solvents promises to dramatically affect their ability to remediate contaminated sites.

Wang, P.; Woodward, C.A.; Kaufman, E.N. (Oak Ridge National Lab., TN (United States). Chemical Technology Div.)

1999-08-05

15

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

16

Polyethylene glycol modified, cross-linked starch-coated iron oxide nanoparticles for enhanced magnetic tumor targeting.  

PubMed

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, potentially 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 h) and D20 (11.75 h) showing much longer half-lives than D (0.12 h). Improved plasma stability enhanced tumor MNP exposure 100 (D5) to 150 (D20) fold as measured by plasma AUC(0-?). Sustained tumor exposure over 24 h was visually confirmed in a 9L-glioma rat model (12 mg Fe/kg) using magnetic resonance imaging (MRI). Findings indicate that a polyethylene glycol modified, cross-linked starch-coated MNP is a promising platform for enhanced magnetic tumor targeting, warranting further study in tumor models. PMID:21176955

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

2010-12-21

17

Preparation and cytotoxic activity of poly(ethylene glycol)-modified poly(amidoamine) dendrimers bearing adriamycin  

Microsoft Academic Search

We have developed poly(amidoamine) (PAMAM) dendrimers that have poly(ethylene glycol) (PEG) grafts at all dendrimer chain ends. To obtain PEG-modified dendrimers with sites for conjugation of anticancer drugs for this study, we prepared PAMAM G4 dendrimers that have a glutamic acid (Glu) residue at every chain end of dendrimer; PEG chains were attached to amino groups of Glu residues. We

Kenji Kono; Chie Kojima; Nobuyuki Hayashi; Eiko Nishisaka; Katsuyuki Kiura; Shinobu Watarai; Atsushi Harada

2008-01-01

18

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

19

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

2012-07-22

20

Intermembrane transfer of polyethylene glycol-modified phosphatidylethanolamine as a means to reveal surface-associated binding ligands on liposomes.  

PubMed

In order to explore the use of exchangeable poly(ethylene glycol) (PEG)-modified diacylphosphatidylethanolamines (PE) to temporarily shield binding ligands attached to the surface of liposomes, a model reaction based on inhibition and subsequent recovery of biotinylated liposome binding to streptavidin immobilized on superparamagnetic iron oxide particles (SA magnetic particles) was developed. PEG-lipid incorporation into biotinylated liposomes decreased liposome binding to SA magnetic particles in a non-linear fashion, where as little as 0.1 mol% PEG-PE resulted in a 20% decrease in binding. Using an assay based on inhibition of binding, PEG(2000)-PE transfer from donor liposomes to biotinylated acceptor liposomes could be measured. The influence of temperature and acyl chain composition on the transfer of PEG-diacyl PEs from donor liposomes to acceptor liposomes, consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine, cholesterol and N-((6-biotinoyl)amino)hexanoyl)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (54.9:45:0.1 mole ratio), was measured. Donor liposomes were prepared using 1,2-distearoyl-sn-glycero-3-phosphocholine (50 mol%), cholesterol (45 mol%) and 5 mol% of either PEG-derivatized 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE-PEG(2000)), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE-PEG(2000)), or 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-PEG(2000)). Transfer of DSPE-PEG(2000) to the donor liposomes was not detected under the conditions employed. In contrast, DMPE-PEG(2000) was transferred efficiently even at 4 degrees C. Using an acceptor to donor liposome ratio of 1:4, the time required for DMPE-PEG(2000) to become evenly distributed between the two liposome populations (T(EQ)) at 4 degrees C and 37 degrees C was approx. 2 and <0.5 h, respectively. An increase in acyl chain length from C14:0 to C16:0 of the PEG-lipid resulted in a significant reduction in the rate of transfer as measured by this assay. The transfer of PEG-lipid out of biotinylated liposomes was also studied in mice following intravenous administration. The relative rates of transfer for the various PEG-lipids were found to be comparable under in vivo and in vitro conditions. These results suggest that it is possible to design targeted liposomes with the targeting ligand protected while in the circulation through the use of PEG-lipids that are selected on the basis of exchange characteristics which result in exposure of the shielded ligand following localization within a target tissue. PMID:11470091

Li, W M; Xue, L; Mayer, L D; Bally, M B

2001-08-01

21

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

22

Radioprotection by polyethylene glycol-protein complexes in mice  

SciTech Connect

Polyethylene glycol of about 5000 D was activated with cyanuric chloride, and the activated compound was complexed to each of three proteins. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase were each radioprotectants when administered prophylactically to female B6CBF1 mice before irradiation. The dose reduction factor for these mice was 1.2 when 5000 units of polyethylene glycol-catalase was administered before /sup 60/Co irradiation. Female B6CBF1 mice administered prophylactic intravenous injections of catalase, polyethylene glycol-albumin, or heat-denatured polyethylene glycol-catalase had survival rates similar to phosphate-buffered saline-injected control mice following /sup 60/Co irradiation. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase have radioprotective activity in B6CBF1 mice, which appears to depend in part on enzymatic activities of the complex. However, no radioprotective effect was observed in male C57BL/6 mice injected with each polyethylene glycol-protein complex at either 3 or 24 hr before irradiation. The mechanism for radioprotection by these complexes may depend in part on other factors.

Gray, B.H.; Stull, R.W.

1983-03-01

23

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

24

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 CF4 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

2013-10-10

25

A Colorimetric Assay for Estimation of Polyethylene Glycol and Polyethylene Glycolated Protein Using Ammonium Ferrothiocyanate  

Microsoft Academic Search

A colorimetric method for quantitative assay of polyethylene glycol (PEG) described here is based on partitioning of a chromophore present in ammonium ferrothiocyanate reagent from an aqueous to a chloroform phase in the presence of PEG. The method is simple, reproducible, and can detect PEG in amounts as low as 5 ?g. It gives a linear response over a range

Alo Nag; Gargi Mitra; Prahlad C. Ghosh

1996-01-01

26

Plasma proteins adsorption mechanism on polyethylene-grafted poly(ethylene glycol) surface by quartz crystal microbalance with dissipation.  

PubMed

Protein adsorption has a vital role in biomaterial surface science because it is directly related to the hemocompatibility of blood-contacting materials. In this study, monomethoxy poly(ethylene glycol) (mPEG) with two different molecular weights was grafted on polyethylene as a model to elucidate the adsorption mechanisms of plasma protein through quartz crystal microbalance with dissipation (QCM-D). Combined with data from platelet adhesion, whole blood clotting time, and hemolysis rate, the blood compatibility of PE-g-mPEG film was found to have significantly improved. Two adsorption schemes were developed for real-time monitoring of protein adsorption. Results showed that the preadsorbed bovine serum albumin (BSA) on the surfaces of PE-g-mPEG films could effectively inhibit subsequent adsorption of fibrinogen (Fib). Nonspecific protein adsorption of BSA was determined by surface coverage, not by the chain length of PEG. Dense PEG brush could release more trapped water molecules to resist BSA adsorption. Moreover, the preadsorbed Fib could be gradually displaced by high-concentration BSA. However, the adsorption and displacement of Fib was determined by surface hydrophilicity. PMID:23659226

Jin, Jing; Jiang, Wei; Yin, Jinghua; Ji, Xiangling; Stagnaro, Paola

2013-05-23

27

Polyethylene glycol modified, cross-linked starch-coated iron oxide nanoparticles for enhanced magnetic tumor targeting  

Microsoft Academic Search

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, potentially enhanced

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

2011-01-01

28

Why do polyethylene glycols behave as a stabilizer and a destabilizer of protein structure  

SciTech Connect

The ability of organic co-solvents to serve as stabilizer or destabilizer of proteins is the net result of a series of interactions between co-solvents and the native-denatured states of the protein. In an effort to test the applicability of thermodynamic principles governing protein stability, the effects of polyethylene glycols on the stability of bovine serum albumin and chymotrypsinogen were studied. Protein stability was monitored by exposing proteins to guanidine hydrochloride and urea. Results show that these proteins unfold in higher concentrations of denaturant in the presence of polyethylene glycols. These denaturation results are in direct contrast to that of thermal denaturation, which showed that polyethylene glycols destabilize proteins. Polyethylene glycols serve as a stabilizer of proteins towards chemical denaturation because the presence of denaturants has disrupted the hydrophobic interactions between the co-solvent and unfolded state of the protein, an interaction that probably is the dominant factor in thermal denaturation. Thus, the ability of the same co-solvent to serve as a stabilizer or destabilizer of proteins depends on the nature of interactions between co-solvent and protein states under specific environmental conditions.

Shilong Yuan; Lee, Lee, L.L.Y.; Tsang, A.; Lee, J.C. (Univ. of Texas, Galveston (United States))

1991-03-11

29

Ultrafast Solvation Dynamics of Subtilisin-Polyethylene Glycol Interaction for Protein Crystallization  

NASA Astrophysics Data System (ADS)

We study the ultrafast solvation dynamics of protein-precipitant complexes. Protein subtilisin carlsberg (SC) was mixed with several polyethylene glycol (PEG) precipitants for protein crystallization. Picosecond-resolved emission spectra from single intrinsic tryptophan residue (Trp-113) are recorded to construct solvation correlation functions. For precipitant concentrations with various crystallization effects, we observe drastically different solvation relaxation processes. These differences in solvation dynamics are correlated with the local protein structural integrity and water-network stability upon interaction with the precipitants. The solvation dynamics at the protein surface is proposed as a new perspective to study precipitant-protein interactions.

Ding, Qing; Meng, Geng; Wang, Shu-Feng; Zheng, Xiao-Feng; Yang, Hong; Gong, Qi-Huang

2011-06-01

30

HPCPC Separation of Proteins using Polyethylene Glycol-Potassium Phosphate Aqueous Two-Phase  

Microsoft Academic Search

High Performance Centrifugal Partition Chromatography (HPCPC) is a practical and suitable method, particularly on the preparative scale, for the separation of biomolecules such as proteins, enzymes, etc. Aqueous two-phase system is also very attractive for the isolation of biomolecules. Aqueous polymer phase system composed of polyethylene glycol 6000-potassium phosphate has been used for the countercurrent chromatographic separation of bovine serum

J. Chen; G. X. Ma; D. Q. Li

1999-01-01

31

Surface properties of copolymers of alkyl methacrylates with methoxy (polyethylene oxide) methacrylates and their application as protein-resistant coatings.  

PubMed

New polymeric surfactants, copolymers of alkyl methacrylates with methoxy (polyethylene oxide) methacrylates, were synthesized and characterized by gel permeation chromatography. They were studied as possible means to produce polyethylene oxide-rich surfaces by a simple coating treatment on common hydrophobic medical materials. They were further studied as cleaners for the removal of proteins preadsorbed on hydrophobic surfaces. The surface properties of the copolymers such as the adsorption properties of the copolymer on a hydrophobic surface, low density polyethylene, the protein-resistant character of the prepared polyethylene oxide surfaces and the effectiveness of the copolymers for removal of proteins pre-adsorbed on the surface, were investigated by X-ray photoelectron spectroscopy and by using 125I-labelled copolymers and 125I-labelled proteins. The surface properties of the synthesized copolymers were compared with those of commercially available polyethylene oxide containing block copolymer surfactants. PMID:2242394

Lee, J H; Kopeckova, P; Kopecek, J; Andrade, J D

1990-09-01

32

Polyethylene Glycol-Potassium Phosphate Aqueous Two-Phase Systems for Countercurrent Chromatography of Proteins  

Microsoft Academic Search

Aqueous-aqueous polymer phase systems composed of polyethylene glycol 1000-potassium phosphate were used for the countercurrent chromatographic separation of proteins using the type XL cross-axis coil planet centrifuge. It was found that the peak resolution of proteins is highly dependant on the pH of the solvent system. The best separation of cytochrome c, myoglobin and human serum albumin was achieved with

Y. Shibusawa; M. Yamaguchi; Y. Ito

1998-01-01

33

Protein adsorption to chemisorbed polyethylene oxide thin films  

Microsoft Academic Search

A major area of biomaterials research is the development of surfaces that reduce or eliminate non-specific protein adsorption. End-tethered PEO has been shown to reduce protein and cell interactions at the tissue-material interface; the effects of polymer chain length, chain density and end-group chemistry are not yet completely understood. To date, there have been few detailed, systematic studies that have

Larry David Unsworth

2005-01-01

34

Sustained release of human growth hormone from in situ forming hydrogels using self-assembly of fluoroalkyl-ended poly(ethylene glycol).  

PubMed

Poly(ethylene glycol)s modified with fluorocarbon end groups are capable of in situ transition from an injectable liquid to a viscoelastic hydrogel by hydrophobic interaction of the end groups; this class of materials is useful for a variety of biomedical applications, including sustained protein release. The hydrogel state can be transformed into an injectable state by the addition of a toxicologically acceptable organic solvent, such as N-methyl pyrrolidone; after injection, this solution quickly returns to a gel state by diffusion of the water-miscible organic solvent into the surrounding environment. In vitro characterization of sustained release of human growth hormone (hGH) using this injectable depot shows that hGH remains stable inside the hydrogel formed, and demonstrates more than 2 weeks of prolonged release of hGH complexed with Zn(2+) ions without protein aggregation or initial burst. PMID:15792553

Tae, Giyoong; Kornfield, Julia A; Hubbell, Jeffrey A

2005-09-01

35

Protein quantification in the presence of poly(ethylene glycol) and dextran using the Bradford method  

Microsoft Academic Search

Some experimental methodologies require the quantification of protein in the presence of polymers like poly(ethylene glycol) (PEG) and dextran (DEX). In the aqueous two-phase system (ATPS) extraction of biomolecules, the interference of these phase-forming polymers on the Bradford quantification assay is commonly recognized. However, how these polymers interfere has not been reported hitherto. In this study we show that while

Helder Barbosa; Nigel K. H. Slater; Joăo C. Marcos

2009-01-01

36

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

37

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

38

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

2013-01-18

39

Selective adsorption of protein on micropatterned flexible poly(ethylene terephthalate) surfaces modified by vacuum ultraviolet lithography  

NASA Astrophysics Data System (ADS)

Protein micropattern was fabricated on the flexible poly(ethylene terephthalate) (PET) surfaces modified by vacuum ultraviolet lithography (VUV). Chemical composition and topographies changes of the modified PET surfaces were characterized and analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and static water contact angle. As demonstrated in fluorescence microscope, the protein patterns were surrounded by a protein-repellant layer of poly(ethylene glycol) (PEG) that were faithful reproductions of the copper mesh. These results suggested that this technique can be extended to other polymeric materials and will be useful in fields where arrays of protein patterns are desired.

Li, Shaoying; Wu, Zhongkui; Tang, Hongxiao; Yang, Jun

2012-03-01

40

Infrared investigation on the conformation of proteins deposited on polyethylene films  

NASA Astrophysics Data System (ADS)

Aqueous protein solutions deposited and dried on thin polyethylene sheets were analyzed by Fourier transform infrared spectroscopy. This convenient technique provided reasonable determinations of secondary structure with 200 to 80 (mu) g of protein deposited. To determine secondary structure, principal component regression (PCR) was applied to the infrared spectra of 12 different proteins deposited as thin films. Regression with 5 principal components provided the fraction of helix and (beta) -sheet structure present in the hydrated proteins with standard deviations of 6.3% and 7.3%, respectively, compared to a reference data set of structures determined by x-ray crystallography. Prediction errors were similar to those obtained by other infrared methods. Analysis of various types of turn structure grouped together was unsuccessful.

Sarver, Ronald W.; Krueger, William C.

1994-01-01

41

Photochemical immobilization of proteins and peptides on benzophenone-terminated boron-doped diamond surfaces.  

PubMed

The successful covalent linking of green fluorescence protein and streptavidin to patterned benzophenone-modified boron-doped diamond (BDD) electrodes is demonstrated. Photoreactive benzophenone moieties were covalently grafted to oxidized diamond surfaces via an esterification reaction. Patterned BDD surfaces were obtained using a UV/ozone lithographic approach either on hydrogen-terminated BDD or on poly(ethylene)-glycol-modified BDD surfaces. UV light (lambda = 365 nm) irradiation of the patterned BDD surfaces in the presence of green fluorescence protein (GFP) or streptavidin resulted in the covalent immobilization of the proteins. The presence of poly(ethylene) glycol chains reduces significantly the nonspecific adsorption of the proteins. The success of the photoimmobilization of streptavidin was evidenced through biomolecular interaction with avidin. The preservation of the biological activity was furthermore underlined by photoimmobilization of peptides directly onto benzophenone modified BDD using a photomask. PMID:19821607

Marcon, Lionel; Wang, Mei; Coffinier, Yannick; Le Normand, Francois; Melnyk, Oleg; Boukherroub, Rabah; Szunerits, Sabine

2010-01-19

42

Protein cell-surface display through in situ enzymatic modification of proteins with a poly(Ethylene glycol)-lipid.  

PubMed

Cell-surface display of functional proteins is a powerful and useful tool for regulating and reinforcing cellular functions. Direct incorporation of site-specifically lipidated proteins from the extracellular medium is more rapid, easily controllable and reliable in displaying active proteins than expression through gene transfer. However, undesirable amphiphilic reagents such as organic co-solvents and detergents were required for suppressing aggregation of ordinary lipidated proteins in solution. We report here sortase A-catalyzed modification of proteins with a poly(ethylene glycol)(PEG)-lipid in situ on the surface of living cells. Proteins fused with a recognition tag were site-specifically ligated with the PEG-lipid which was preliminary incorporated into cell membranes. Accordingly, target proteins were successfully displayed on living cells without aggregation under an amphiphilic reagent-free condition. Furthermore, to demonstrate the availability of the present method, Fc domains of immunoglobulin G were displayed on cancer cells, and the phagocytosis of cancer cells with dendritic cells were enhanced through the Fc-Fc receptor interaction. Thus, the present facile chemoenzymatic method for protein display can be utilized for modulating cell-cell interactions in cell and tissue engineering fields. Biotechnol. Bioeng. 2013;110: 2785-2789. © 2013 Wiley Periodicals, Inc. PMID:23592269

Tomita, Urara; Yamaguchi, Satoshi; Maeda, Yasukazu; Chujo, Kazuki; Minamihata, Kosuke; Nagamune, Teruyuki

2013-04-26

43

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

44

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

2012-08-07

45

Adsorption of plasma proteins on polyethylene oxide-modified lipid bilayers studied by total internal reflection fluorescence  

Microsoft Academic Search

Distearoylphophatidylcholine (DSPC) mixed with various mole percentages of polyethylene oxide (number average molecular weight 2000)-grafted distearoylphosphatidylethanolamine (PEO2000-DSPE) were deposited on DSPE-coated quartz surfaces by the Langmuir–Blodgett deposition. Structural transitions in PEO2000 from pancake to mushroom, and from mushroom to brush conformations were revealed from film balance experiments. Adsorption kinetics of proteins from 1% platelet-poor plasma (PPP) on the supported lipid

Zhong Xu; Roger E Marchant

2000-01-01

46

Grafting of poly(ethylene glycol) onto poly(acrylic acid)-coated glass for a protein-resistant surface.  

PubMed

The surface of solid glass supports for samples in optical microscopy and for biosensors needs to be protein-resistant. A coating of a poly(ethylene glycol) monomethyl ether (mPEG) on the surface of the glass is one promising method for preventing the nonspecific adsorption of proteins. In this study, we have developed a novel technique for achieving an optimal coverage of a glass surface with mPEG to prevent protein adhesion. A clean glass substrate previously treated with (3-aminopropyl)dimethylethoxysilane (APDMES) was treated sequentially with poly(acrylic acid) and subsequently a primary amine derivative of mPEG in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The resultant glass surface was demonstrated to be highly protein-resistant, and the adsorption of bovine serum albumin decreased to only a few percentage points of that on a glass surface treated with APDMES alone. Furthermore, to extend the present method, we also prepared a glass substrate on which biotinylated poly(ethylene glycol) was cografted with mPEG, and biotinylated myosin subfragment-1 (biotin-S1) was subsequently immobilized on this substrate by biotin/avidin chemistry. Actin filaments were observed to glide on the biotin-S1-coated glass surface in the presence of ATP, and thus, the method is capable of immobilizing the protein specifically without any loss in its biological function. PMID:16615763

Wazawa, Tetsuichi; Ishizuka-Katsura, Yoshiko; Nishikawa, So; Iwane, Atsuko Hikikoshi; Aoyama, Shigeru

2006-04-15

47

Poly(ethylene oxide) layers grafted to dopamine-melanin anchoring layer: stability and resistance to protein adsorption.  

PubMed

In this study, we propose substrate-independent modification for creating a protein-repellent surface based on dopamine-melanin anchoring layer used for subsequent binding of poly(ethylene oxide) (PEO) from melt. We verified that the dopamine-melanin layer can be formed on literally any substrate and could serve as the anchoring layer for subsequent grafting of PEO chains. Grafting of PEO from melt in a temperature range 70-110 °C produces densely packed PEO layers showing exceptionally low protein adsorption when exposed to the whole blood serum or plasma. The PEO layers prepared from melt at 110 °C retained the protein repellent properties for as long as 10 days after their exposure to physiological-like conditions. The PEO-dopamine-melanin modification represents a simple and universal surface modification method for the preparation of protein repellent surfaces that could serve as a nonfouling background in various applications, such as optical biosensors and tissue engineering. PMID:21823677

Pop-Georgievski, Ognen; Popelka, Št?pán; Houska, Milan; Chvostová, Dagmar; Proks, Vladimír; Rypá?ek, František

2011-08-25

48

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

49

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

50

Improving Protein Delivery from Microparticles Using Blends of Poly(DL lactide co-glycolide) and Poly(ethylene oxide)-poly(propylene oxide) Copolymers  

Microsoft Academic Search

Purpose. Microparticles containing ovalbumin as a model for protein drugs were formulated from blends of poly(DL lactide-co-glycolide) and poly(ethylene oxide)-poly(propylene oxide) copolymers (Pluronic). The objectives were to achieve uniform release characteristics and improved protein delivery capacity.

Ming-Kung Yeh; Stanley S. Davis; Allan G. A. Coombes

1996-01-01

51

Bacteria-surface interaction in the presence of proteins and surface attached poly(ethylene glycol) methacrylate chains.  

PubMed

This study analyzes the adhesion behavior of the gram positive bacteria, Staphylococcus aureus (S. aureus), and the gram negative bacteria, Escherichia coli (E. coli), on polypyrrole (PPY) surfaces in the presence of poly(ethylene glycol) methacrylate (PEGMA) chains and plasma proteins (bovine serum albumin and bovine plasma fibrinogen) either preadsorbed on the film surface or in the bacterial suspension. Bacterial adhesion experiments performed in a suspension of bacterial cells and protein may give important insights on the behavior of bacterial adhesion in an in vivo environment. Protein adsorption and bacterial adhesion on PEGMA-grafted PPY films were reduced by about a factor of 2-4 compared with those on the pristine PPY films. In addition, the number of bacterial cells adhering on the substrate is dependent not only on the type of protein present, but also the sequence of exposure to the protein relative to the bacteria. Furthermore, bacteria-surface adhesion force was measured using the atomic force microscopy with increasing lateral force to detach the individual cell. The adhesion force of S. aureus is influenced by PEGMA and plasma protein modification and is significantly higher than that of E. coli for all substrates tested. The number of adherent cells on the substrate is shown to be directly correlated to the bacterial adhesion force. PMID:17295255

Tedjo, Chrysanty; Neoh, K G; Kang, E T; Fang, Ning; Chan, Vincent

2007-08-01

52

Investigation of the interaction between poly(ethylene glycol) and protein molecules using low field nuclear magnetic resonance.  

PubMed

A comprehensive insight into the interaction between proteins and poly(ethylene glycol) (PEG) is crucial to understand the behavior of PEG, which is widely used in pharmaceutical and medical applications. Although PEG is believed to be an excellent material to resist non-specific protein adsorption, there is a lack of quantitative information about the interactions between proteins and PEG. In this paper the interactions of bovine serum albumin (BSA) and lysozyme (LYZ) with different molecular weight (MW) PEGs were investigated through the T2 relaxation time of PEGs measured by low field nuclear magnetic resonance spectroscopy. The integrated signal intensity of PEGs was quantified under various conditions from the concentrations and MWs of PEG, and ionic strength of solutions, as well as the molar ratios of PEG to protein. The results show that a large number of PEG molecules could associate with protein molecules with association constants in the range ~10(4)-10(5) M(-1). The association constant is insensitive to the ionic strength change in the physiological range and the lowest associate constant occurs at the medium MW PEG with protein. This suggests that the interaction between PEG and protein molecules might not be negligible in investigations of the resistance to non-specific protein adsorption. Long chain PEG coatings might cause modest protein adsorption, which could interfere with any weak specific interaction between ligand and receptor. Thus, it is necessary to reconsider the popular accepted method of protecting nanoparticles (NP) in blood with long chain PEG coatings since these NPs might be surrounded by a layer of weakly adsorbed plasma protein in the circulatory system. PMID:23318816

Wu, Jiang; Wang, Zhen; Lin, Weifeng; Chen, Shengfu

2013-01-11

53

Synthesis of an oxynitride-based green phosphor Ba3Si6O12N2:Eu via an aqueous-solution process, using propylene-glycol-modified silane  

Microsoft Academic Search

An almost pure phase of Ba3Si6O12N2 doped with Eu was successfully synthesized through the ammonia nitridation of an oxide precursor prepared through an aqueous-solution method, using propylene- glycol-modified silane. The emission peak intensity of the obtained Ba3Si6O12N2:Eu was?2.2 times higher than that of the sample prepared through a solid-state reaction method.

Chihiro Yasushita; Hideki Kato; Masato Kakihana

2012-01-01

54

Improving biocompatibility by controlling protein adsorption: Modification and design of biomaterials using poly(ethylene glycol) microgels and microspheres  

NASA Astrophysics Data System (ADS)

Guided by the clinical needs of patients and developments in biology and materials science, the primary focus of the biomaterials field remains at the solid/liquid interface between biomaterial surfaces and biological fluids. For blood-contacting devices, biological responses are initially elicited and directed by proteins that adsorb from this multicomponent solution to form thin films on their surfaces. The identity, conformation, and quantity of adsorbed proteins are related to the properties of a material's surface. For example, hydrophobic surfaces tend to be thrombotic via interactions between platelets and adsorbed fibrinogen, while surface-activation of specific enzymes initiates the coagulation cascade on hydrophilic surfaces. The objective of this thesis is to improve the design of biomaterials through the analysis and control of adsorbing protein layers. This goal is approached through three separate strategies. First, a proteomics-based methodology is presented for the assessment of protein conformation at the residue level after adsorption to biomaterial surfaces. A quantitative mass spectrometric technique is additionally suggested for the identification and quantification of proteins within adsorbed protein layers. Second, a method is described for the covalent attachment of poly(ethylene glycol) (PEG)-based hydrogel coatings onto biomaterials surfaces for the minimization of protein adsorption. The coatings are applied using partially crosslinked PEG solutions containing polymer and protein oligomers and microgels that can be designed to control cell adhesion. Finally, a modular strategy is proposed for the assembly of bioactive PEG-based hydrogel scaffolds. This was accomplished using novel PEG microspheres with diverse characteristics that individually contribute to the ability of the scaffold to direct cellular infiltration. The methodologies proposed by this thesis contribute to the recent shift in biomaterials and tissue engineering strategies towards directed cellular responses at the molecular level.

Scott, Evan Alexander

55

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

2012-07-14

56

Preparation of protein- and cell-resistant surfaces by hyperthermal hydrogen induced cross-linking of poly(ethylene oxide).  

PubMed

The functionalization of surfaces with poly(ethylene oxide) (PEO) is an effective means of imparting resistance to the adsorption of proteins and the attachment and growth of cells, properties that are critical for many biomedical applications. In this work, a new hyperthermal hydrogen induced cross-linking (HHIC) method was explored as a simple one-step approach for attaching PEO to surfaces through the selective cleavage of C-H bonds and subsequent cross-linking of the resulting carbon radicals. In order to study the effects of the process on the polymer, PEO-coated silicon wafers were prepared and the effects of different treatment times were investigated. Subsequently, using an optimized treatment time and a modified butyl polymer with increased affinity for PEO, the technique was applied to butyl rubber surfaces. All of the treated surfaces exhibited significantly reduced protein adsorption and cell growth relative to control surfaces and compared favorably with surfaces that were functionalized with PEO using conventional chemical methods. Thus HHIC is a simple and effective means of attaching PEO to non-functional polymer surfaces. PMID:21491963

Bonduelle, Colin V; Lau, Woon M; Gillies, Elizabeth R

2011-04-26

57

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

PubMed

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 took place between the hydroxyl group of PEG and the epoxy group of the P(GMA-DVB) solid medium in the presence of boron trifluoride. The density of PEG immobilized onto the P(GMA-DVB) can be determined easily by saponification of modified microsphere firstly and then titration of glycerol-PEG. The effect of the cross-linker content of microsphere on the density of PEG immobilization was investigated. Molecular weight of PEG was found to influence the PEG-immobilization density, which subsequently affects the hydrophilicity of the modified P(GMA-DVB). Bovine serum albumin (BSA) and trypsin were used as model proteins to examine the adsorption and desorption properties of the modified P(GMA-DVB) microspheres. The results demonstrated that P(GMA-DVB) porous microsphere with 20% DVB and modified with PEG4000 showed excellent adsorption and desorption properties. Adsorption capacity of BSA on the modified microsphere attained to 51.6 mg/g microsphere, and BSA mass recovery and trypsin activity recovery was up to 97.6% and 98.7%, respectively. The modified microsphere was demonstrated to be a promising hydrophobic interaction chromatography material for purification of protein. PMID:16824738

Wang, Renwei; Zhang, Ying; Ma, Guanghui; Su, Zhiguo

2006-05-26

58

The stability and immunogenicity of a protein antigen encapsulated in biodegradable microparticles based on blends of lactide polymers and polyethylene glycol  

Microsoft Academic Search

Protein-loaded microparticles were produced from blends of poly(ethylene glycol) (PEG) with poly(l-lactide) (PLA) homopolymer or poly(dl-lactide co-glycolide) copolymers (PLG) using a water-in oil-in oil method. The stability of ovalbumin (OVA) associated with microparticles prepared using PEG and 50:50 PLG, 75:25 PLG and PLA, respectively, was analysed by SDS-PAGE and quantified by scanning densitometry following incubation in PBS at 37°C for

E. C Lavelle; M.-K Yeh; A. G. A Coombes; S. S Davis

1999-01-01

59

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

PubMed

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 (250mmx4.6mm id, 5microm), each positional isomer of the mono-PEGylated octreotides was completely resolved with good resolution (PEG-2K: 7.6, PEG-5K: 6.6, and PEG-20K: 3.1). The optimal RP-HPLC condition also resolved the degradation products of mono-PEG-octreotide isomers in thermal stability studies at 55 degrees C and enzymatic stability studies with trypsin. In conclusion, the developed RP-HPLC method will be valuable for studying the effect of PEGylation site and the attached PEG size on the physicochemical and pharmacological properties of PEGylated octreotides. PMID:19766229

Park, Eun Ji; Lee, Kang Choon; Na, Dong Hee

2009-09-12

60

Poly(ethylene glycol) as stabilizer and emulsifying agent: a novel stabilization approach preventing aggregation and inactivation of proteins upon encapsulation in bioerodible polyester microspheres.  

PubMed

Protein aggregation and inactivation are major problems associated with the encapsulation of pharmaceutical proteins in biodegradable microspheres. The objectives of this study were to identify the causes of aggregation and inactivation of two model enzymes upon solid-in-oil-in-water (s/o/w) encapsulation in poly(lactic-co-glycolic) acid (PLGA) microspheres in order to rationally develop approaches assuring their stability. S/o/w encapsulation of gamma-chymotrypsin in PLGA microspheres caused aggregation of ca. 30% and halved its specific activity. Co-lyophilization with poly(ethylene glycol) (PEG) substantially reduced the loss in enzyme activity but 8% of the protein still aggregated during encapsulation. Model studies performed under conditions relevant to the encapsulation procedure allowed pinpointing the cause of gamma-chymotrypsin instability, which was mainly the formation of the oil-in-water emulsion. To prevent aggregation in this encapsulation step, the most commonly used emulsifying agent polyvinyl alcohol (PVA) was replaced by PEG because it is known to reduce protein aggregation at interfaces. The use of PEG as the emulsifying agent in the aqueous and organic phase prevented gamma-chymotrypsin inactivation and aggregation during encapsulation. The stabilization approach also worked for the model protein horseradish peroxidase and thus is of a general nature. PMID:12586511

Castellanos, Ingrid J; Crespo, Rubén; Griebenow, Kai

2003-02-14

61

‘Stealth’ corona-core nanoparticles surface modified by polyethylene glycol (PEG): influences of the corona (PEG chain length and surface density) and of the core composition on phagocytic uptake and plasma protein adsorption  

Microsoft Academic Search

Nanoparticles possessing poly(ethylene glycol) (PEG) chains on their surface have been described as blood persistent drug delivery system with potential applications for intravenous drug administration. Considering the importance of protein interactions with injected colloidal dug carriers with regard to their in vivo fate, we analysed plasma protein adsorption onto biodegradable PEG-coated poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA) and poly(?-caprolactone) (PCL)

R Gref; M Lück; P Quellec; M Marchand; E Dellacherie; S Harnisch; T Blunk; R. H Müller

2000-01-01

62

Reduction of protein adsorption and macrophage and astrocyte adhesion on ventricular catheters by polyethylene glycol and N-acetyl-L-cysteine.  

PubMed

Cellular obstruction of poly(dimethyl)siloxane (PDMS) catheters is one of the most prevalent causes of shunt failure in the treatment of hydrocephalus. By modifying PDMS using short- and long-chain mono-functional polyethylene glycol (PEG604 and PEG5K, respectively) and N-acetyl-L-cysteine via adsorption and covalent binding (NAC and NAC/EDC/NHS, respectively), we increased surface wettability. We hypothesized that these surface modifications would inhibit protein adsorption and decrease host macrophage and astrocyte adhesion. Tested in a bioreactor set to mimic physiological flow, all modified surfaces significantly decreased albumin adsorption compared with PDMS (p < 0.05) except for PEG604-modified PDMS (p = 0.14). All four modification strategies significantly reduced (p < 0.01) fibronectin adsorption. PEG604, PEG5K, NAC, and NAC/EDC/NHS reduced the average level of macrophage adhesion by 53%, 63%, 40%, and 58% (p <.0.05 except when comparing PDMS with NAC) and astrocyte adhesion by 47%, 83%, 91%, and 72% (p < 0.05 except when comparing PDMS with PEG604), respectively. Combined with saline soak results which suggest that the surface wettability is stable over 30 days for each modification, our results are consistent with the hypothesis that these modifications decrease cell adhesion on catheters in vitro for the treatment of hydrocephalus. PMID:21630435

Harris, Carolyn A; Resau, James H; Hudson, Eric A; West, Richard A; Moon, Candice; Black, Andrew D; McAllister, James P

2011-05-31

63

Physical characterizations of microemulsion systems using tocopheryl polyethylene glycol 1000 succinate (TPGS) as a surfactant for the oral delivery of protein drugs.  

PubMed

Attempts were to develop microemulsion systems using medium chain triglyceride, deionized water, and TPGS as surfactant for the oral delivery of protein drugs or poorly water-soluble drugs. Phase diagrams were constructed to elucidate the phase behavior of systems composed of Captex 300 and water with D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) as main surfactant, polysorbates (Tween 20, Tween 40, Tween 60 and Tween 80) as adjuvant surfactants, and polyethylene glycols (PEG 400 and PEG 600) and polyols (ethanediol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol and glycerin) as cosurfactants. The ratios of TPGS to Tweens, PEGs or polyols (K(m)) were set at 4/1, 2/1, 1/1, 1/2, and 1/4. The phase diagram for H(2)O/Captex 300/TPGS system reveals that when TPGS was used as a sole surfactant, it is not capable of producing isotropic solutions of water and oil over a wide range of the compositions. H(2)O/Captex 300/TPGS/Tweens systems with various K(m), regardless of the adjuvant surfactant used were capable of producing an isotropic phase. The extension of microemulsion phase and the presence and extension of the gel phase were found to be dependent on the surfactant mixture. The phase diagrams of H(2)O/Captex 300/TPGS systems using polyols as cosurfactants demonstrate that the types of polyols have a slight effect on the region of existence of the microemulsions. Comparison between the isotropic regions for the polyols system reveals that as the relative concentration of polyols increase, the isotropic region decrease in size. This decrease is towards the S(mix)-water axis indicating that as the relative concentration of polyols increases the maximum amount of oil solubilized decreases. The gel region decreased in size with the increase of polyols weight ratio. All polyols do not solubilized Captex 300 without using TPGS as surfactant. PMID:15653166

Ke, Wen-Ting; Lin, Shyr-Yi; Ho, Hsiu-O; Sheu, Ming-Thau

2005-02-01

64

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

65

Rubber-polyethylene Modified Bitumens  

Microsoft Academic Search

ffect of the blends of different polyethylenes (LDPE = low-density polyethylene, LLDPE = linear low density polyethylene and HDPE = high density polyethylene) and rubbers (PBR = polybutadiene rubber, SBR = styrene butadiene random copolymer, NR = natural rubber and SEBS = styrene-ethylene-butylene-styrene block copolymer) on bitumen properties was investigated. PBR-PE Blends form a physical net- work in bitumen medium,

Ali Akbar Yousefi

66

Polyethylene glycol diacrylate-based supermacroporous monolithic cryogel as high-performance liquid chromatography stationary phase for protein and polymeric nanoparticle separation  

Microsoft Academic Search

A supermacroporous monolithic cryogel was directly prepared by in situ cryo-copolymerization in a stainless steel cartridge (70mm×5.0mm I.D.) using methacrylic acid (MAA) as functional monomer and polyethylene glycol diacrylate (PEGDA) as crosslinker. The highly crosslinked (90%, molar ratio) poly(MAA–PEGDA) cryogel had more uniform supermacropores with a mean diameter of 25?m compared to the poly(acrylamide)-based cryogels. The viability of poly(MAA–PEGDA) cryogel

Zhiyong Chen; Li Xu; Yuan Liang; Jianbin Wang; Meiping Zhao; Yuanzong Li

2008-01-01

67

Polyethylene Glycol 3350  

MedlinePLUS

Polyethylene glycol 3350 may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: nausea bloating cramping gas Some side effects can be serious. The following symptoms are uncommon, but if you experience either of them, ...

68

Synthesis of Polyethylene Magnetic Nanoparticles  

Microsoft Academic Search

Very low molecular weight polyethylene (average MW 700?g\\/mole) magnetic nanocomposite particles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. The particles are further coated with poly dl-lactic acid to functionalize the polyethylene particles for biomedical applications. A solvent-nonsolvent emulsion was made with polyethylene and surface modified iron oxide and was raised to very high temperature followed by

Jhunu Chatterjee; Yousef Haik; Ching-Jen Chen

2002-01-01

69

Modular Poly(Ethylene Glycol) Scaffolds Provide the Ability to Decouple the Effects of Stiffness and Protein Concentration on PC12 Cells  

PubMed Central

This research focused on developing a modular poly(ethylene glycol) (PEG) scaffold, assembled from PEG microgels and collagen I, to provide an environment to decouple the chemical and mechanical cues within a three dimensional scaffold. We first characterized the microgel fabrication process, examining the size, polydispersity, swelling ratio, mesh size, and storage modulus of the polymer particles. The resulting microgels had a low polydispersity, PDI=1.08, and a diameter of ~1.6 ?m. The mesh size of the microgels, calculated from the swelling ratio, was 47.53 Ĺ. Modular hydrogels (modugels) were then formed by compacting EDC/NHS activated microgels with PEG-4arm-amine and 0, 1, 10, or 100 ?g/mL collagen. Stiffness (G*) of the modugels was not significantly altered with the addition of collagen, allowing for modification of the chemical environment independent from the mechanical properties of the scaffold. PC12 cell aggregation increased in modugels as collagen concentrations increased and cell viability in modugels was improved over bulk PEG hydrogels. Overall, these results indicate that further exploration of modular scaffolds formed from microgels could allow for a better understanding of the relationship between the chemical and mechanical properties and cellular behavior.

Scott, Rebecca A.; Elbert, Donald L.; Willits, Rebecca Kuntz

2011-01-01

70

Poly(ethylene glycol)-containing hydrogels in drug delivery  

Microsoft Academic Search

The use of hydrogels as carriers for protein delivery has been a subject of significant recent research. In our recent work, we have shown that diffusion controlled delivery of proteins from hydrogels containing poly(ethylene glycol) (PEG) can be possible and controlled by the three-dimensional structure. In addition, a number of these hydrogel carriers are mucoadhesive and can be used for

Nikolaos A. Peppas; Kelley B. Keys; Madeline Torres-Lugo; Anthony M. Lowman

1999-01-01

71

21 CFR 177.1610 - Polyethylene, chlorinated.  

Code of Federal Regulations, 2010 CFR

...c). Such chlorinated polyethylene contains a maximum of...ii). (b) Chlorinated polyethylene may be used in contact with...this chapter, chlorinated polyethylene is limited to use only as...exceeding 15 weight percent in plastic articles prepared from...

2010-01-01

72

21 CFR 177.1610 - Polyethylene, chlorinated.  

Code of Federal Regulations, 2010 CFR

...c). Such chlorinated polyethylene contains a maximum of...ii). (b) Chlorinated polyethylene may be used in contact with...this chapter, chlorinated polyethylene is limited to use only as...exceeding 15 weight percent in plastic articles prepared from...

2009-04-01

73

Ideal polyethylene nanocrystals.  

PubMed

The water-soluble catalyst precursor [[(2,4,6-(3,5-(CF3)2C6H3)3-C6H2)-N?C(H)-(3-(9-anthryl)-2-O-C6H3)-?(2)-N,O]Ni(CH3)(TPPTS)] (TPPTS = tri(sodiumphenylsulfonate)phosphine) polymerizes ethylene to aqueous dispersions of highly ordered nanoscale crystals (crystallinity ?(DSC) ? 90%) of strictly linear polyethylene (<0.7 methyl-branches/1000 carbon atoms, Mn = 4.2 × 10(5) g mol(-1)). SAXS in combination with cryo-TEM confirms this unusually high degree of order (?(SAXS) = 82%) and shows the nanoparticles to possess a very thin amorphous layer on the crystalline lamella, just sufficient to accommodate a loop, but likely no entanglements. This ideal chain-folded structure is corroborated by annealing studies on the aqueous-dispersed nanoparticles, which show that the chain can move through the crystal as evidenced by lamella thickening without disturbing the crystalline order as concluded from an unaltered low thickness of the amorphous layers. These ideal chain-folded polyethylene nanocrystals arise from the crystallization in the confined environment of a nanoparticle and a deposition of the growing polymer chain on the crystal growth front as the chain is formed by the catalyst. PMID:23855756

Osichow, Anna; Rabe, Christian; Vogtt, Karsten; Narayanan, Theyencheri; Harnau, Ludger; Drechsler, Markus; Ballauff, Matthias; Mecking, Stefan

2013-07-26

74

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

2011-07-21

75

Delamination Controlled Ballistic Resistance of Polyethylene\\/Polyethylene Composite Materials  

Microsoft Academic Search

We have investigated ballistic response of polyethylene\\/polyethylene (PE\\/PE) composites to impact by Uzi bullets. For comparison, limited work was carried out on PE\\/aramid fiber hybrids and PE fiber\\/Polycarbonate plate laminates. The plates exhibited an average ballistic resistance, V50, of approximately 90 m\\/s per 1 kg\\/m2 area density. In term of the protection level per thickness, the ballistic resistance was 76

H. Harel; G. Marom; S. Kenig

2002-01-01

76

Composites a Fibres Polyethylene Haut-Module et Matrice Polyethylene (High Yield Polyethylene Fiber Composite and Polyethylene Matrix).  

National Technical Information Service (NTIS)

The thermomechanical properties of the polyethylene/polythylene composite material are characterized. The tensile properties were investigated at different directions relating to the fiber's axis. Bend tests were also performed. The results show that: the...

C. Marais

1991-01-01

77

Chicken Feather Keratin Films Plasticized with Polyethylene Glycol  

Microsoft Academic Search

Feathers are basically composed of structural proteins, the keratins, and are suitable for preparing biodegradable films, which must present low hygroscopicity and water vapor permeability (WVP). To prepare such films, glycerol and sorbitol are the more common plasticizers, but they lead to hygroscopic films. In this work, the influence of polyethylene glycol (PEG) with different molecular weights on the films’

Sílvia Maria Martelli; Joăo Borges Laurindo

2012-01-01

78

Degradable polyethylene: fantasy or reality.  

PubMed

Plastic waste disposal is one of the serious environmental issues being tackled by our society today. Polyethylene, particularly in packaging films, has received criticism as it tends to accumulate over a period of time, leaving behind an undesirable visual footprint. Degradable polyethylene, which would enter the eco-cycle harmlessly through biodegradation would be a desirable solution to this problem. However, the "degradable polyethylene" which is presently being promoted as an environmentally friendly alternative to the nondegradable counterpart, does not seem to meet this criterion. This article reviews the state of the art on the aspect of degradability of polyethylene containing pro-oxidants, and more importantly the effect these polymers could have on the environment in the long run. On exposure to heat, light, and oxygen, these polymers disintegrate into small fragments, thereby reducing or increasing the visual presence. However, these fragments can remain in the environment for prolonged time periods. This article also outlines important questions, particularly in terms of time scale of complete degradation, environmental fate of the polymer residues, and possible accumulation of toxins, the answers to which need to be established prior to accepting these polymers as environmentally benign alternatives to their nondegradable equivalents. It appears from the existing literature that our search for biodegradable polyethylene has not yet been realized. PMID:21495645

Roy, Prasun K; Hakkarainen, Minna; Varma, Indra K; Albertsson, Ann-Christine

2011-04-15

79

Very low density polyethylene and high density polyethylene blends  

US Patent & Trademark Office Database

Blends of very low density polyethylene produced using metallocene catalysts (mVLDPE) and high density polyethylene (HDPE) are disclosed. The polymer blends include a metallocene-catalyzed VLDPE polymer having a density of less than 0.916 g/cm.sup.3, the VLDPE polymer preferably being linear and without long chain branching, and a HDPE polymer having a density of greater than 0.940 g/cm.sup.3. The polymer blends are particularly suitable in blown and cast film applications.

Farley; James M. (League City, TX); Halle; Richard W. (Houston, TX); Panagopoulos; George (Atlanta, GA); Johnson; Jerry M. (League City, TX)

2006-11-14

80

Profiles in garbage: Polyethylene terephthalate  

SciTech Connect

Polyethylene terephthalate (PET) is a plastic resin used primarily to make bottles. Soft drinks -- along with salad dressing, fruit juices, peanut butter, and other household and consumer products -- use PET bottles. PET also is used for film, sheeting for cups and food trays, oven-safe trays, and other uses. PET is a relatively new packaging resin, first commercialized in the early 1970s. Because it is an ``engineered`` resin, PET is more expensive than commodity resins such as high-density polyethylene (HDPE) and, for the same reason, it is usually the highest valued plastic recyclable.

Miller, C. [Environmental Industry Associations, Washington, DC (United States)

1997-11-01

81

Polyethylenes bearing a terminal porphyrin group.  

PubMed

An ?-[Cu(II)-porphyrin]-polyethylene was synthesized for the first time using copper catalyzed 1,3-dipolar azide-alkyne Huisgen cycloaddition yielding highly colored moiety-substituted polyethylene. PMID:21625698

Unterlass, Miriam M; Espinosa, Edgar; Boisson, Fernande; D'Agosto, Franck; Boisson, Christophe; Ariga, Katsuhiko; Khalakhan, Ivan; Charvet, Richard; Hill, Jonathan P

2011-05-31

82

Adhesion Polyethylene-Terephtalate/Aluminium (Polyethylene-Terephthalate/Aluminum Adhesion).  

National Technical Information Service (NTIS)

The adhesion and adherence properties of an aluminum coating, obtained by vapor phase deposition in a polyethylene-terephthalate film is investigated. The metallized film is a barrier for oxygen and water vapor. A better knowledge of the chemical bonds be...

M. Bou

1991-01-01

83

POLYETHYLENE/KERATIN FIBER COMPOSITES WITH VARYING POLYETHYLENE CRYSTALLINITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Short-fiber reinforced composites are made from keratin fibers obtained from poultry feathers and polyethylenes of varying crystallinity. The chemical nature of the polymer and fiber is kept constant, and the molecular architecture of the polymer is varied. It is found that low crystallinity polye...

84

The diffusion of ions in polyethylene  

Microsoft Academic Search

It was demonstrated that inorganic ions dissolved in water which is in contact with polyethylene will diffuse into the polyethylene. Not all ions were found to diffuse at the same rate. It was also found that polyethylene in contact with salt solutions will absorb water, with more water being absorbed as the salt concentration is increased. The diffusion was found

T. Bao; J. Tanaka

1991-01-01

85

Bulk Modulus of Polyethylene Oxide.  

National Technical Information Service (NTIS)

A compressibility pressure-temperature cycle has been developed for polyethylene oxide (PEO) by which both the melting and freezing points of this polymer are easily determined. It was found that PEO supercools about 10C and that the pressure dependencies...

R. W. Warfield B. Hartmann

1972-01-01

86

Ultrasonic Absorption in Polyethylene Oxide.  

National Technical Information Service (NTIS)

Ultrasonic absorption measurements were made on high molecular weight polyethylene oxide from room temperature to above the melting point and from 3 MHz to 11 MHa. No peak in absorption was found at the melting point because the test frequencies were all ...

B. Hartmann J. Jarzynski

1970-01-01

87

Waste product profile: Polyethylene terephthalate  

SciTech Connect

Polyethylene terephthalate (PET) is a plastic resin used primarily to make bottles. Soft drinks are the primary product packaged in PET. Salad dressing, peanut butter, and other household and consumer products also use PET bottles. PET is also used for film, sheeting for cups and food trays, ovenable trays, and other uses. PET is a relatively new packaging resin, first commercialized in the early `70s. Because it is an ``engineered`` resin, it is more expensive than commodity resins such as high-density polyethylene (HDPE). The primary market for recycled PET is the fiber industry, which uses PET for carpet fiber, sweaters and other clothing, and for other uses. Recycled PET can also be used for food and beverage containers. Export markets, particularly Asian countries, are becoming increasingly important.

Miller, C. [Environmental Industry Associations, Washington, DC (United States)

1996-02-01

88

Polyethylene multiwalled carbon nanotube composites  

Microsoft Academic Search

Polyethylene (PE) multiwalled carbon nanotubes (MWCNTs) with weight fractions ranging from 0.1 to 10wt% were prepared by melt blending using a mini-twin screw extruder. The morphology and degree of dispersion of the MWCNTs in the PE matrix at different length scales was investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and wide-angle X-ray diffraction

Tony McNally; Petra Pötschke; Peter Halley; Michael Murphy; Darren Martin; Steven E. J. Bell; Gerard P. Brennan; Daniel Bein; Patrick Lemoine; John Paul Quinn

2005-01-01

89

Molecular Motion in Polyethylene. II  

Microsoft Academic Search

Nuclear magnetic relaxation times T1 and T2 have been measured in various polyethylene melts to 200°C. Two distinct T2's can be resolved in all cases but single T1's have been found. T1 is never equal to T2. A self-consistent explanation is offered in terms of the theory of Kubo and Tomita as modified by (1) the assumption of a very

David W. McCall; Dean C. Douglass; Ernest W. Anderson

1959-01-01

90

CERAMIC ON CROSSLINKED POLYETHYLENE IN TOTAL HIP REPLACEMENT: ANY BETTER THAN METAL ON CROSSLINKED POLYETHYLENE?  

Microsoft Academic Search

The authors evaluated the use of ceramic fe- moral heads on crosslinked polyethylene bearing couples versus metal on crosslinked polyethylene couples in a consecutive series of hips performed by a single surgeon over a one year interval. Cera- mic femoral heads and more extensively crosslin- ked polyethylene were used more commonly in the younger aged patients with utilization of ceramic

John J. Callaghan; Steve S. Liu

91

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

92

Light transmission through polyethylene samples  

NASA Astrophysics Data System (ADS)

A spectral calibration Hg(Ar) lamp and a pulsed Nd:YAG laser were employed to study the UV, VIS and IR light transmission through polyethylene samples, as pure and doped with Fe2O3 and carbon nanotubes. Optical measurements were performed in the spectral range between 200 nm and 800 nm. Measurements with 0.1% and 1% in weight of filler concentrations were investigated. The polymers' optical absorption coefficients, calculated from the experimental transmitted component, were tabulated at different wavelengths as a function of the analyzed samples. The radiation depth penetration was also evaluated.

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

2012-03-01

93

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.

Virtanen; Kari (Asheville, NC)

2008-07-15

94

21 CFR 177.1630 - Polyethylene phthalate polymers.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Polyethylene phthalate polymers. 177.1630 Section 177.1630...CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...177.1630 Polyethylene phthalate polymers. Polyethylene phthalate...

2009-04-01

95

21 CFR 177.1630 - Polyethylene phthalate polymers.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Polyethylene phthalate polymers. 177.1630 Section 177.1630...CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...177.1630 Polyethylene phthalate polymers. Polyethylene phthalate...

2010-01-01

96

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

97

Single lamella nanoparticles of polyethylene.  

PubMed

We present a complete analysis of the structure of polyethylene (PE) nanoparticles synthesized and stabilized in water under very mild conditions (15 degrees C, 40 atm) by a nickel-catalyzed polymerization in aqueous solution. Combining cryogenic transmission electron microscopy (cryo-TEM) with X-ray scattering, we demonstrate that this new synthetic route leads to a stable dispersion of individual PE nanoparticles with a narrow size distribution. Most of the semicrystalline particles have a hexagonal shape (lateral size 25 nm, thickness 9 nm) and exhibit the habit of a truncated lozenge. The combination of cryo-TEM and small-angle X-ray scattering demonstrates that the particles consist of a single crystalline lamella sandwiched between two thin amorphous polymer layers ("nanohamburgers"). Hence, these nanocrystals that comprise only ca. 14 chains present the smallest single crystals of PE ever reported. The very small thickness of the crystalline lamella (6.3 nm) is related to the extreme undercooling (more than 100 degrees C) that is due to the low temperature at which the polymerization takes place. This strong undercooling cannot be achieved by any other method so far. Dispersions of polyethylene nanocrystals may have a high potential for a further understanding of polymer crystallization as well as for materials science as, e.g., for the fabrication of extremely thin crystalline layers. PMID:17564476

Weber, C H M; Chiche, A; Krausch, G; Rosenfeldt, S; Ballauff, M; Harnau, L; Göttker-Schnetmann, I; Tong, Q; Mecking, S

2007-06-12

98

EFFECT OF IONIZING RADIATION ON POLYETHYLENE INSULATION  

Microsoft Academic Search

The effect of ionizing radiations on the properties of polyethylene was ; studied. Wires consisting of a copper conductor 1 mm in diameter, insulated by a ; layer of polyethylene 0.5 mm thick, were irradiated with various doses. The ; properties of the irradiated insulation were studied, particular attention being ; devoted to the thermal stability of the insulation, which

V. L. Karpov; Yu. M. Malinskii; L. V. Mitrofanova; S. T. Sinitsyn; E.. E. Finkel; A. S. Fridman; S. M. Chernetsov

1961-01-01

99

How competitive is linear low density polyethylene  

SciTech Connect

Predicts that as convertors adapt new techniques to exploit properties of linear low density polyethylene, use will shift away from other polyethylenes. The basic manufacturing process for all types of polyethylene centers around 4 variables: monomers, catalysts, heat and pressure. Comparing production costs for high pressure low density polyethylene (HPLDPE) and low pressure low density polyethylene (LPLDPE) begins with the 4 variables. Monomer and catalysts remain fairly constant as a main component of total cost. The large differences occur with heat and pressure. Estimated cost saving of operating a LPLDPE reactor is almost 25% less than that of a HPLDPE reactor. Areas where LPLDPE will begin to dominate include the film market, injection molding, rotomolding, wire and cable jacketing, and blow molding. Concludes that it is only a matter of time before existing HPLDPE plants reach obsolescence. The only negatives in LPLDPE concern the plastic convertors and extrusion equipment producers.

Crimmin, S.M.

1982-12-01

100

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

101

Microbial Degradation of Polyethylene Glycols  

PubMed Central

Mono-, di-, tri-, and tetraethylene glycols and polyethylene glycols (PEG) with molecular weight up to 20,000 were degraded by soil microorganisms. A strain of Pseudomonas aeruginosa able to use a PEG of average molecular weight 20,000 was isolated from soil. Washed cells oxidized mono and tetraethylene glycols, but O2 consumption was not detectable when such cells were incubated for short periods with PEG 20,000. However, the bacteria excreted an enzyme which converted low- and high-molecular-weight PEG to a product utilized by washed P. aeruginosa cells. Gas chromatography of the supernatant of a culture grown on PEG 20,000 revealed the presence of a compound co-chromatographing with diethylene glycol. A metabolite formed from PEG 20,000 by the extracellular enzyme preparation was identified as ethylene glycol by combined gas chromatography-mass spectrometry.

Haines, J. R.; Alexander, M.

1975-01-01

102

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

2005-12-20

103

Irradiation effects in high-density polyethylene  

NASA Astrophysics Data System (ADS)

Using molecular dynamics simulations, we have studied the irradiation effects in high density polyethylene. We found that the governing reactions were chain scissioning and generation of free radicals, whereas cross-linking and recombination of chain fragments was rare. We also determined the threshold energy for creating defects in the polyethylene lattice as a function of the incident angle. Our analysis on the damage threshold energy shows that it is strongly dependent on the initial recoil direction and on average two times higher for the carbon atoms than for the hydrogen atoms in the polyethylene chain.

Polvi, Jussi; Nordlund, Kai

2013-10-01

104

Polyethylenimine–PEG coated albumin nanoparticles for BMP2 delivery  

Microsoft Academic Search

Bone Morphogenetic Protein-2 (BMP-2) plays an important role in stimulating new bone formation, and has been utilized in clinical bone repair by implantation. In this study, we report a nanoparticulate (NP) system for BMP-2 delivery based on bovine serum albumin (BSA) NPs stabilized with a poly(ethylene glycol) modified polyethylenimine (PEI–PEG) coating. PEI–PEG with different PEG substitutions were synthesized, and the

Sufeng Zhang; Cezary Kucharski; Michael R. Doschak; Walter Sebald; Hasan Uluda?

2010-01-01

105

Thermal Stability of Cross-Linked Polyethylene.  

National Technical Information Service (NTIS)

The investigation demonstrated the fact that many different forms of polymerized trimethyl dihydro quinoline are available and that the 150C. oven aging characteristics of cross-linked polyethylene are sometimes affected by which of the various forms is e...

A. C. Bluestein J. C. Henderson

1966-01-01

106

Nanostructured carbon coatings on polyethylene films  

Microsoft Academic Search

The properties of medical low-density polyethylene films with carbon coatings improving the biological compatibility of the polymer were studied by electron and scanning atomic-force microscopy, as well as by IR, Raman, visible, and UV spectroscopy.

A. P. Alekhin; A. G. Kirilenko; R. I. Romanov; A. A. Sigarev

2003-01-01

107

21 CFR 177.1620 - Polyethylene, oxidized.  

Code of Federal Regulations, 2013 CFR

...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES...air oxidation of polyethylene conforming to the density, maximum n- hexane extractable...

2013-04-01

108

21 CFR 177.1610 - Polyethylene, chlorinated.  

Code of Federal Regulations, 2013 CFR

...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES...chlorination of polyethylene conforming to the density, maximum n- hexane extractable...

2013-04-01

109

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2010 CFR

...mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether. 721.1729 Section 721.1729 Protection...mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether....

2009-07-01

110

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2010 CFR

...mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether. 721.1729 Section 721.1729 Protection...mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether....

2010-07-01

111

Composite particles of polyethylene @ silica.  

PubMed

Polyethylene (PE) and silica are perhaps the simplest and most common organic and inorganic polymers, respectively. We describe, for the first time, a physically interpenetrating nanocomposite between these two elementary polymers. While polymer-silica composites are well known, the nanometric physical blending of PE and silica has remained a challenge. A method for the preparation of such materials, which is based on the entrapment of dissolved PE in a polymerizing tetraethoxysilane (TEOS) system, has been developed. Specifically, the preparation of submicron particles of low-density PE@silica and high-density PE@silica is detailed, which is based on carrying out a silica sol-gel polycondensation process within emulsion droplets of TEOS dissolved PE, at elevated temperatures. The key to the successful preparation of this new composite has been the identification of a surfactant, PE-b-PEG, that is capable of stabilizing the emulsion and promoting the dissolution of the PE. A mechanism for the formation of the particles as well as their inner structure are proposed, based on a large battery of analyses, including transmission electron microscopy (TEM) and scanning electron microscopies (SEM), surface area and porosity analyses, various thermal analyses including thermal gravimetric analysis (TGA/DTA) and differential scanning calorimetry (DSC) measurements, small-angle X-ray scattering (SAXS) measurements and solid-state NMR spectroscopy. PMID:17199288

Sertchook, Hanan; Elimelech, Hila; Makarov, Carina; Khalfin, Rafail; Cohen, Yachin; Shuster, Michael; Babonneau, Florence; Avnir, David

2007-01-10

112

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

Microsoft Academic Search

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

M. Wang; M. Chandrasekaran; W. Bonfield

2002-01-01

113

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

114

Homocomposites of chopped fluorinated polyethylene fiber with low-density polyethylene matrix  

Microsoft Academic Search

Conventional composites are generally prepared by adding reinforcing agent to a matrix and the matrix wherein the reinforcing agents are different in chemical composition with the later having superior mechanical properties. This work presents the preparation and properties of homocomposites consisting of a low-density polyethylene (LDPE) matrix and an ultra high molecular weight polyethylene (UHMWPE) fiber reinforcing phase. Direct fluorination

J. Maity; C. Jacob; C. K. Das; S. Alam; R. P. Singh

2008-01-01

115

Charge storage and transport in high density polyethylene and low density polyethylene  

Microsoft Academic Search

High density polyethylene (HDPE) and low density polyethylene (LDPE) are widely used as dielectrics and insulating materials. In this paper, the influence of heat treatment during and after corona charging on charge storage stability and the transportation of detrapping charges in the bulk of HDPE and LDPE were investigated by isothermal surface potential decay and open-circuit TSD analysis. The shifts

Jian Jiang; Zhongfu Xia; Hongyan Zhang; Zhenzhong Wang

1996-01-01

116

Recovery of Plastic Low-Density Polyethylene\\/High-Density Polyethylene (LDPE\\/HDPE) Wastes  

Microsoft Academic Search

In order to show the importance of plastic recycling, a study of the mechanical, thermal and thermodegradative properties of low-density polyethylene (LDPE) blends with virgin and recycled high-density polyethylene (HDPE) was made to assess the possibility of using recycled polymers, and consequently, reducing environmental pollution brought about by those materials. The formation of an additional phase was determined through thermal

C. Albano; G. Sanchez; A. Ismayel; P. Hernández

1999-01-01

117

Dielectric Properties and Crystalline Morphology of Low Density Polyethylene Blended with Metallocene Catalyzed Polyethylene  

Microsoft Academic Search

Dielectric properties of low-density polyethylene (LDPE) blended with metallocene catalyzed polyethylene (MPE) to 1, 3, 5 wt% of the latter are reported. It was found that the 1 wt% MPE blend had the lowest volume resistivity, the highest direct current (DC) breakdown strength and the least accumulated space charge. The crystalline morphology of the blends was studied through differential scanning

X. Wang; H. Q. He; D. M. Tu; C. Lei; Q. G. Du

2008-01-01

118

Space Charge Distribution and Crystalline Structure in Low-Density Polyethylene modified by Metallocene Catalyzed Polyethylene  

Microsoft Academic Search

A small amount of metallocene catalyzed polyethylene (MPE) was blended into low-density polyethylene (LDPE) in this paper. Then the space charge profile in the blends was measured by pulsed electro-acoustic (PEA) method, which showed that the space charges were greatly decreased and field distributions tended to be uniform in LDPE blended with 1 wt% MPE. At the same time the

Wang Xia; Wu Chaoyi; Tu Demin; Lei Chao; Du Qiangguo

2006-01-01

119

Thermal effects in high density polyethylene and low density polyethylene at high hydrostatic pressures  

Microsoft Academic Search

The temperature changes as a result of rapid hydrostatic pressure applications are reported for high density polyethylene (HDPE) and low density polyethylene (LDPE) in the reference temperature range from 298 to 423 K and in the pressure range from 13.8 to 200 MN m-2. The adiabatic temperature changes were found to be a function of pressure and temperature. A curve

E. L. Rodriguez; F. E. Filisko

1987-01-01

120

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

121

Solubility behavior of enzymes after addition of polyethylene glycol to erythrocyte hemolysates.  

PubMed

The addition of polyethylene glycol to a hemolysate of rat erythrocytes reduces the solubility of phosphofructokinase and glucose-6-phosphate and 6-phosphogluconate dehydrogenases in an exponential manner with respect to polymer concentration. Analyses of the solubility curves (log solubility versus polymer concentration) obtained at different pH values suggest that the solubility can be related to both the aggregation state and the intrinsic solubility of the proteins promoted by solution conditions. These findings suggest the possibility of using polyethylene glycol in a rational way for the fractional precipitation of a mixture. PMID:2969251

Delgado, C; Rubio, A; Luque, J; Tejedor, M C

1988-06-01

122

Influence of trehalose on conformational and dynamical properties of Poly(Ethylene Oxide) in water  

Microsoft Academic Search

This paper reports the results of a study on Poly(Ethylene Oxide)\\/trehalose\\/water mixtures performed by Photon Correlation Spectroscopy. The chemical structure of the polymer, simpler than that of proteins and its helical conformation in water, constitute a useful starting point for understanding the more complex protein\\/trehalose\\/water interactions. The obtained findings support the ``water-replacement'' hypothesis, indicating that a direct polymer-trehalose interaction occurs.

V. Villari; C. Branca; A. Faraone; S. Magazů; G. Maisano; P. Migliardo

2000-01-01

123

The Radiothermoluminescence Of The Chlorinated Polyethylene  

NASA Astrophysics Data System (ADS)

The radiothermoluminescence (RTL) of the high density polyetilene (HDPE) by gamma-irradiation was studied together with the thermally stimulated currents (TSC). The investigation was carried for several kind of samples: pure high density polyethlene and chlorinated high density polyethlene with 7, 28 and 42 per cent chlorine. It has been established, that the intensity of the radiothermoluminescence decreases on the high density polyethylene with the chlorination and the thermally stimulated currents increase as a function of the temperature T has been observed as well that a new phase has been formed in the chlorinated polyethylene with the both methods of the investigation.

Polizov, Hristo T.

2007-04-01

124

Improved streptococcal grouping antisera containing polyethylene glycol.  

PubMed

Antisera to streptococcal groups A through G containing 4% polyethylene glycol 6000 were prepared and evaluated. Seventy strains of homologous and heterologous beta- and non-beta-hemolytic streptococci were included in the evaluation. Homologous reactions were determined against extracts prepared by four extraction methods: hot hydrochloric acid (Lancefield) extraction, autoclave extraction, hot formamide extraction, and nitrous acid extraction. Enhancement of the precipitin reaction in the presence of polyethylene glycol 6000 permitted a fourfold dilution of all antisera for use in the capillary precipitin test. At this dilution, the potency of the antisera exceeded requirements established for these reagents. PMID:7026609

George, J R; Ashworth, H; Facklam, R R; Harrell, W K; Palmer, D F

1981-10-01

125

Securing Containerized Hazardous Wastes with Polyethylene Resin and Fiberglass Encapsulates.  

National Technical Information Service (NTIS)

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) a...

H. R. Lubowitz R. W. Telles

1981-01-01

126

Chemically Cross-Linked Heat-Shrinkable Polyethylene Tubes.  

National Technical Information Service (NTIS)

The memory effect of heat-shrinkable tubes made of low density polyethylene obtained by irradiation with accelerated electrons is presented. The dependence of the cross-linked polyethylene contraction force on time, temperature, degree of cross-linking, e...

C. Cazac I. Mihalcea S. Ilie S. Jipa V. Contineanu

1986-01-01

127

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

Federal Register 2010, 2011, 2012, 2013

...Review)] Polyethylene Terephthalate (Pet) Film From Korea AGENCY: United States...duty order on polyethylene terephthalate (PET) film from Korea...whether revocation of the antidumping order on PET film from Korea would be likely to...

2011-02-15

128

Structure property relationships in polyethylene\\/montmorillonite nanodielectrics  

Microsoft Academic Search

The influence of a montmorillonite (MMT) nanoclay, functionalized with dimethyl-di(hydrogenated tallow) quaternary amine, on structural evolution and electrical characteristics of a designed polyethylene system has been studied. Samples were prepared by mixing a polyethylene\\/MMT masterbatch into a matrix system containing 10% high density polyethylene and 90% low density polyethylene using an extruder; X-ray diffraction results suggest good dispersion and exfoliation,

C. D. Green; A. S. Vaughan; G. R. Mitchell; T. Liu

2008-01-01

129

Linear Low-Density Polyethylene for Cable Sheath.  

National Technical Information Service (NTIS)

The paper describes the applicability of linear low-density polyethylene (L-LDPE) to cable sheath. Six grades of L-LDPE, low-density polyethylene (LDPE) copolymer and high-density polyethylene (HDPE) were tested for physical properties, extrusion and resi...

Y. Morita S. Iwata H. Itoh

1986-01-01

130

Isolation and characterization of polyethylene-biodegrading mycromycetes  

Microsoft Academic Search

The polyethylene biodegradation by microorganisms is a solution for the reduction of the plastics pollution. Isolation and characterization of the fungi capable to degrade the polyethylene are reported, as well as the conditions of pH and temperature in which they showed the higher activity. Fungi were isolated from polyethylene products obtained of sanitary landfill; the identification was realized in base

Carmen R. Méndez; Germán Vergaray; Vilma R. Béjar; Karina J. Cárdenas

131

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

132

Carbon Fibers from Polyethylene-Based Precursors  

Microsoft Academic Search

Polyethylene fibers are attractive as carbon fiber precursors due to their high carbon content and ease of manufacture. Also, highly ordered and oriented fibers with extraordinary physical and mechanical properties are available today. However, being thermoplastic fibers, they soften or melt at a fairly low temperature, losing their fiber form. These precursors have to be stabilized by introducing cross links

Dong Zhang; Gajanan S. Bhat

1994-01-01

133

MISCIBLE POLYETHYLENE GLYCOL-CITRIC ACID GELS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Polyethylene glycol (PEG) and citric acid (CA) are crystalline solids at room temperature. The materials are opaque, hard, brittle materials. However, blending the PEG and CA shows that a clear, soft 'gel' is formed at certain concentrations. Rheology, differential scanning calorimetry (DSC), FT-...

134

Poly(ethylene glycol) Star Polymer Hydrogels  

Microsoft Academic Search

Poly(ethylene glycol) (PEG) star polymer hydrogels were prepared by Á-irradiation of aqueous solutions of star PEG polymers. The swelling behavior of these gels in deionized water at 37 °C indicated that the gels prepared from PEG star polymers with a small number of long arms swelled to a greater extent than those prepared from PEG star polymers with a large

Kelley Britton Keys; Fotios M. Andreopoulos; Nikolaos A. Peppas

1998-01-01

135

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

136

IRRADIATION OF POLYETHYLENE. IV. OXIDATION EFFECTS  

Microsoft Academic Search

The radiolytic oxidation of a linear polyethylene has been studied by ; measuring changes in total pressure, by observing increases in optical density in ; the infrared due to carbonyl absorbance, and by analyzing gaseous products of ; oxidation when polgethylene film of different thicknesses was exposed to gamma ; radiation in the initial presence of a few centimeters pressure

Hiroshi Matsuo; Malcolm Dole

1959-01-01

137

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

138

Fracture mechanisms in wood fibre reinforced polyethylene  

Microsoft Academic Search

The fracture toughness of wood fibre reinforced polyethylene has been studied and several methods of improving this important property have been developed. A mechanistic fracture model which incorporates the features of wood fibres and the fibre\\/matrix interface was also developed. The modeling revealed that the key to enhancing the fracture toughness is to promote fibre pull-out during composite fracture. Based

Chengjie Zhang

1997-01-01

139

Ductile Brittle Transition of Low Density Polyethylene.  

National Technical Information Service (NTIS)

An extensive test program to determine the brittleness of low density, blown polyethylene film was undertaken as a result of failures of high altitude balloons constructed of this film. In this work, ductility and brittleness are defined by the ultimate e...

D. Weissmann

1972-01-01

140

Tensile Deformation of Polyethylenes: Crystallinity Effects  

Microsoft Academic Search

The crystalline fraction of polyethylene can be reduced by increasing the cooling rate, the molecular weight or the fraction of comonomer. All three methods have been used in this study of tensile deformation which shows that true stress - true strain behavior depends systematically on morphology. The dependence of uniaxial yield stress on crystal thickness is well understood in terms

Buckley Crist; Costas Metaxas

2004-01-01

141

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

142

POLYETHYLENE ENCAPSULATES FOR HAZARDOUS WASTE DRUMS  

EPA Science Inventory

This capsule report summarizes studies of the use of polyethylene (P.E.) for encapsulating drums of hazardous wastes. Flat PE sheet is welded to roto moded PE containers which forms the encapsulates. Plastic pipe welding art was used, but the prototype welding apparatus required ...

143

Surface modification of poly(ethylene terephthalate) by plasma polymerization of poly(ethylene glycol)  

Microsoft Academic Search

Poly(ethylene glycol) (PEG) was ‘polymerized’ onto poly(ethylene terephthalate) (PET) surface by radio frequency (RF) plasma\\u000a polymerization of PEG (average molecular weight 200 Da) at a monomer vapour partial pressure of 10 Pa. Thin films strongly\\u000a adherent onto PET could be produced by this method. The modified surface was characterized by infra red (IR) spectroscopy,\\u000a scanning electron microscopy (SEM), atomic force microscopy (AFM),

D. Sakthi Kumar; Masayori Fujioka; Kentaro Asano; Atsumu Shoji; Athipettah Jayakrishnan; Yasuhiko Yoshida

2007-01-01

144

Poly(ethylene oxide) blends with poly(ethylene oxide)\\/poly(dicyclohexyl itaconate) block copolymers  

Microsoft Academic Search

Blends of poly(ethylene oxide) and block copolymers poly(ethylene oxide)-block-poly(dicyclohexyl itaconate)s (PEO-b-PDCHI) with different molecular masses were prepared by solution casting from chloroform. Thermal properties and kinetics of nonisothermal melting and crystallization were studied using differential scanning calorimetry. The lamella thickness (average size of the crystals), the transport energy through the phase boundary and the surface free energy were determined and

Aleksandra Buzarovska; Slobodanka Koseva; Maja Cvetkovska; Emanuel Nedkov

2001-01-01

145

Molecular Dynamics Studies of Polyethylene Oxide and Polyethylene Glycol: Hydrodynamic Radius and Shape Anisotropy  

Microsoft Academic Search

A revision (C35r) to the CHARMM ether force field is shown to reproduce experimentally observed conformational populations of dimethoxyethane. Molecular dynamics simulations of 9, 18, 27, and 36-mers of polyethylene oxide (PEO) and 27-mers of polyethylene glycol (PEG) in water based on C35r yield a persistence length ?=3.7Ĺ, in quantitative agreement with experimentally obtained values of 3.7Ĺ for PEO and

Hwankyu Lee; Richard M. Venable; Alexander D. MacKerell; Richard W. Pastor

2008-01-01

146

Degradation of low-density polyethylene and cross-linked polyethylene by partial discharge  

Microsoft Academic Search

To study the degradation of low-density polyethylene (LDPE) and cross-linked polyethylene (XLPE) by partial discharge (PD), experiments were conducted in a nitrogen (N2) and (N2+O2) gas atmosphere. After being subjected to the PD, samples were examined using atomic force microscopy (AFM) and FTIR. The AFM images clearly revealed the creation of pits on the surface of degraded samples. A large

Yasuo Sekii

2010-01-01

147

Mechanical Properties of Blends of Low-Density Polyethylene with Chlorinated Polyethylene  

Microsoft Academic Search

The results of experimental investigation into the mechanical properties of blends of low-density polyethylene (LDPE) with chlorinated polyethylene (CPE) in tension are presented. The specimens of pure LDPE, CPE, and nine types of LDPE\\/CPE blends, with different content of components at 10 wt.% intervals, were examined. Data on the influence of blend composition on the tensile stress-strain diagram, elastic modulus,

R. D. Maksimov; T. Ivanova; J. Zicans; V. Kalkis

2005-01-01

148

Epitaxial crystallization of linear low-density polyethylene on high-density polyethylene  

Microsoft Academic Search

The oriented crystallization of linear low-density polyethylene (LLDPE) on high-density polyethylene (HDPE) has been investigated\\u000a by transmission electron microscopy. From morphology and electron diffraction, it is confirmed that epitactic growth of LLDPE\\u000a lamellae on the HDPE crystals takes place with an adoption of the HDPE crystal thickness at the interface and a continuous\\u000a thinning of the LLDPE lamellae in the

J. LOOS; F. KATZENBERG; J PETERMANN

1997-01-01

149

ABA-triblock copolymers from biodegradable polyester A-blocks and hydrophilic poly(ethylene oxide) B-blocks as a candidate for in situ forming hydrogel delivery systems for proteins  

Microsoft Academic Search

Hydrogels are very attractive delivery systems for hydrophilic macromolecules such as proteins and DNA because they provide a protective environment and allow control of diffusion by adjusting cross-link densities. Physically cross-linked hydrogels generated by rapid swelling upon exposure to an aqueous environment can be obtained from ABA triblock copolymers containing hydrophobic polyester A-blocks and hydrophilic polyether B-blocks. They provide an

Thomas Kissel; Youxin Li; Florian Unger

2002-01-01

150

Effect of Metallocene-Catalyzed Polyethylene on the Physicomechanical Properties of Blends with High-Density Polyethylene or Low-Density Polyethylene  

Microsoft Academic Search

The physicomechanical properties of polymer blend formulations comprising different grades of metallocene-catalyzed linear low-density polyethylenes (mLLDPEs) with high-density polyethylenes (HDPEs) or a low-density polyethylene (LDPE) were investigated. For blends with HDPE, the addition of mLLDPE improves the Izod impact strength and some tensile properties. For blends with LDPE, adding mLLDPE increases the ductility and the percent elongation at break.

Marlene J. Cran; Stephen W. Bigger

2009-01-01

151

Polyethylene glycol as an alternative polymer solvent for nanoparticle preparation.  

PubMed

Solvent toxicity is one of the major drawbacks in the preparation of polymeric nanoparticles today. Here, polyethylene glycols (PEGs) are proposed as non-toxic solvents for the preparation of polymeric nanoparticles. Based on a preparation process similar to the solvent displacement technique, several process parameters were examined for their effects on the properties of the prepared nanoparticles by this method to achieve the optimum preparation conditions. The investigated parameters included polymer type and concentration, volume and temperature of the dispersing phase, methods of dispersing the solvent phase into the non-solvent phase, duration and speed of stirring and washing by dialysis. Ammonio methacrylate copolymer (Eudragit RL), poly-lactide-co-glycolide (PLGA), and PEG-PLGA were found to be successful polymer candidates for the preparation of nanoparticles by this method. Nanoparticles with diameters ranging from 80 to 400nm can be obtained. The encapsulation efficiencies of bovine serum albumin, and lysozyme as model proteins were ranging from 7.3±2.2% to 69.3±1.8% depending on the strength of polymer-protein interaction. Biological assays confirmed a full lysozyme activity after the preparation process. PEG proved to be a suitable non-toxic solvent for the preparation of polymeric protein-loaded nanoparticles, maintaining the integrity of protein. PMID:23958752

Ali, Mohamed Ehab; Lamprecht, Alf

2013-08-16

152

Short-term adhesion and long-term biofouling testing of polydopamine and poly(ethylene glycol) surface modifications of membranes and feed spacers for biofouling control.  

PubMed

Ultrafiltration, nanofiltration membranes and feed spacers were hydrophilized with polydopamine and polydopamine-g-poly(ethylene glycol) surface coatings. The fouling propensity of modified and unmodified membranes was evaluated by short-term batch protein and bacterial adhesion tests. The fouling propensity of modified and unmodified membranes and spacers was evaluated by continuous biofouling experiments in a membrane fouling simulator. The goals of the study were: 1) to determine the effectiveness of polydopamine and polydopamine-g-poly(ethylene glycol) membrane coatings for biofouling control and 2) to compare techniques commonly used in assessment of membrane biofouling propensity with biofouling experiments under practical conditions. Short-term adhesion tests were carried out under static, no-flow conditions for 1 h using bovine serum albumin, a common model globular protein, and Pseudomonas aeruginosa, a common model Gram-negative bacterium. Biofouling tests were performed in a membrane fouling simulator (MFS) for several days under flow conditions similar to those encountered in industrial modules with the autochthonous drinking water population and acetate dosage as organic substrate. Polydopamine- and polydopamine-g-poly(ethylene glycol)-modified membranes showed significantly reduced adhesion of bovine serum albumin and P. aeruginosa in the short-term adhesion tests, but no reduction of biofouling was observed during longer biofouling experiments with modified membranes and spacers. These results demonstrate that short-term batch adhesion experiments using model proteins or bacteria under static conditions are not indicative of biofouling, while continuous biofouling experiments showed that membrane surface modification by polydopamine and polydopamine-g-poly(ethylene glycol) is not effective for biofouling control. PMID:22578432

Miller, Daniel J; Araújo, Paula A; Correia, Patricia B; Ramsey, Matthew M; Kruithof, Joop C; van Loosdrecht, Mark C M; Freeman, Benny D; Paul, Donald R; Whiteley, Marvin; Vrouwenvelder, Johannes S

2012-04-19

153

Stabilization of polyethylene coatings against light aging  

SciTech Connect

The problem of protection of metallic constructions against corrosion and prolongation of their life is important for science and technology. Protection of metal surfaces against atmospheric corrosion by the use of polymeric coatings is of special interest. One promising polymer for this purpose could be polyethylene (PE), but it is well known that PE undergoes atmospheric aging under the influence of solar radiation, and this has a sharply adverse effect on its physical and mechanical properties. Study of the stabilization of polyethylene coatings is of interest in this connection. Experimental data justifies the view that the inhibiting action of ferrocene and its derivatives depends on their volatility and compatibility with PE, the value of the OPR, and the nature of the functional groups present in the cyclopentadienyl rings of the ferrocene molecule.

Tkachenko, T.I.; Kalennikov, E.A.; Koretskaya, L.S.

1983-04-20

154

Speciation of antimony in polyethylene terephthalate bottles  

SciTech Connect

Antimony contamination has been reported in drinking water from polyethylene terephthalate (PET) bottles. Micro-X-ray fluorescence (XRF) analysis has been used to identify the distribution and chemical form of residual antimony used as a catalyst in the manufacture of PET bottles. The results are consistent with clusters of Sb(III) having dimensions of the order of tens of micrometers, clearly showing the ability of synchrotron radiation analyses to both map elemental distribution and determine oxidation state.

Martin, R.R.; Ablett, J.; Shotyk, W.S.; Naftel, S.; Northrup, P.

2009-12-18

155

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

156

Hemocompatible Polyethylene Glycol Films on Silicon  

Microsoft Academic Search

A simple hemocompatibility-enhancing technique for immobilizing a self-assembled polyethylene glycol multilayer onto silicon surfaces is introduced. It involves the functionalization of PEG by SiCl3 groups on its chain ends, and the reaction of the PEG organosilicon derivatives with hydroxylated groups on silicon surfaces. Surface properties of the treated surfaces were characterized by contact angle measurement, electron spectroscopy for chemical analysis,

Miqin Zhang; Mauro Ferrari

1998-01-01

157

Dielectric Relaxations in Polyoxymethylene and Polyethylene Oxide  

Microsoft Academic Search

Dielectric properties in the frequency range 10-1 to 106 c\\/s are studied above 100°C for polyoxymethylene (POM) and above -32°C for polyethylene oxide (PEO). In case of POM, a dielectric dispersion which corresponds to the mechanical alpha dispersion in its frequency and temperature position is observed and is assigned to the crystalline phase. The relaxation strength \\\\varDelta\\\\varepsilon of this dispersion

Kunio Arisawa; Kenji Tsuge; Yasaku Wada

1965-01-01

158

Rheological properties of polyethylene oxide solutions  

Microsoft Academic Search

Summary Measurements were made on solutions of Polyethylene oxide (WSR-301) varying in concentration from .0511 g\\/dl to 4.014 g\\/dl, prepared from two samples of dry material of different ages (I, II), using aWeissenberg Rheogoniometer with cone-and-plate and parallel-plate geometries, and also using capillary viscometers. Steady shear data were obtained for eight decades of strain-rates (10-3 k 5 sec-1), and oscillatory

R. L. Powell; W. H. Schwarz

1975-01-01

159

Polyethylene bags and solar ultraviolet radiation  

SciTech Connect

This technical comment questions the use of polyethylene bags to collect and store samples in a previously reported study on the effects of solar ultraviolet radiation on natural phytoplankton assemblages in Antarctic waters. A significant difference in the photosynthetic rates was noted for samples in glassware as opposed to bags, although the overall conclusions remained similar. A response by the original authors is included. 1 tab.

Holm-Hansen, O.; Helbling, E.W. (Univ. of California, San Diego, La Jolla (United States))

1993-01-22

160

A glow discharge treatment to immobilize poly(ethylene oxide)\\/poly(propylene oxide) surfactants for wettable and non-fouling biomaterials  

Microsoft Academic Search

A non-fouling (protein resistant) polymer surface was achieved using an argon glow discharge treatment of a polyethylene surface which had been precoated with various poly(ethylene oxide)\\/poly(propylene oxide)\\/poly(ethylene oxide) (PEO-PPO-PEO) tri-block copolymer surfactants. The surfactant is first deposited on the polymer surface via a solvent swelling and evaporation method. Then the coated surfactant is immobilized on the substrate surface by an

M. S. Sheu; A. S. Hoffman; J. Feijen

1992-01-01

161

Purification of extracellular ?-amylase from Bacillus subtilis by partitioning in a polyethylene glycol\\/potassium phosphate aqueous two-phase system  

Microsoft Academic Search

A study was made of the partition and purification of ?-amylase from a culture supernatant of Bacillus subtilis C10 in a polyethylene glycol\\/potassium phosphate aqueous two-phase system. Factors that influenced the partition of the proteins\\u000a in this system, including polyethylene glycol molecular weight and concentration, and potassium phosphate concentration, were\\u000a investigated. The optimum conditions for primary aqueous two-phase extraction were

Nguyen Hoang Loc; Nguyen Thi Thuy Mien; Do Thi Bich Thuy

2010-01-01

162

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

2013-03-06

163

B-Domain deleted recombinant coagulation factor VIII modified with monomethoxy polyethylene glycol.  

PubMed

Recombinant coagulation factor VIII (r-VIII SQ) was chemically modified with monomethoxy poly(ethylene glycol) (mPEG). Three mPEG derivatives were used for coupling to the r-VIII SQ lysines, a mixed anhydride of monomethoxy poly(ethylene glycol) succinic acid (mPEG-SAH), monomethoxy poly(ethylene glycol) succinimidyl succinate (mPEG-SS), and monomethoxy poly(ethylene glycol) tresylate (mPEG-TRES). A consequence of the modification with all derivatives was a substantial reduction in coagulant activity, even at very low degrees of modification. A method was developed with the purpose of avoiding conjugation at certain important biological sites on the factor VIII and thereby producing conjugates with better retained activity. This was achieved by immobilizing the protein onto a solid matrix during the modification reaction. Characterization of conjugates by SDS-PAGE, western blots, interaction with von Willebrand factor (vWf), and thrombin activation/inactivation analyses was undertaken. The SDS-PAGE and western blots revealed coupling heterogeneity regarding degree of modification. The amount of factor VIII able to bind to vWf decreased with the conjugation. Thrombin activated the modified factor VIII to essentially the same extent as the reference preparation of r-VIII SQ. Inactivation of the modified factor VIII was, however, slower than inactivation of the unmodified protein. Finally, an in vitro study was performed to evaluate the influence of the mPEG modification on the protein stability in extract of porcine tissue. Despite that conjugates with low degrees of modification were included in the study, the coagulant activity was preserved to a significantly higher extent in all incubation mixtures containing conjugates compared to that with unmodified protein. PMID:10821655

Röstin, J; Smeds, A L; Akerblom, E

164

Controlling the Physical Behavior and Biological Performance of Liposome Formulations Through Use of Surface Grafted Poly(ethylene Glycol)  

Microsoft Academic Search

The presence of poly(ethylene glycol) (PEG) at the surface of a liposomal carrier has been clearly shown to extend the circulation lifetime of the vehicle. To this point, the extended circulation lifetime that the polymer affords has been attributed to the reduction or prevention of protein adsorption. However, there is little evidence that the presence of PEG at the surface

C. Allen; N. Dos Santos; R. Gallagher; G. N. C. Chiu; Y. Shu; W. M. Li; S. A. Johnstone; A. S. Janoff; L. D. Mayer; M. S. Webb; M. B. Bally

2002-01-01

165

Immobilization of polyethylene oxide surfactants for non-fouling biomaterial surfaces using an argon glow discharge treatment  

Microsoft Academic Search

A non-fouling (protein-resistant) polymer surface is achieved by the covalent immobilization of polyethylene oxide (PEO) surfactants using an inert gas discharge treatment. Treated surfaces have been characterized using electron spectroscopy for chemical analysis (ESCA), static secondary ion mass spectrometry (SSIMS), water contact angle measurement, fibrinogen adsorption, and platelet adhesion. This paper is intended to review our recent work in using

M.-S. Sheu; A. S. Hoffman; B. D. Ratner; J. Feijen; J. M. Harris

1993-01-01

166

Studies on the Mechanism of Cell Fusion Using Fluorescent Probes Polyethylene Glycol-mediated Membrane and Cytoplasmic  

Microsoft Academic Search

The mechanism by which polyethylene glycol (PEG) mediates cell fusion has been studied by examining the movements of membrane lipids and proteins, as well as cytoplasmic markers, from erythrocytes to monolayers of cultured cells to which they have been fused. Fluorescence and freeze-fracture electron microscopy and fluorescence recovery after photo- bleaching have yielded the following results: (a) In the presence

JOHN W. WOJCIESZYN; ROBERT A. SCHLEGEL; KATHERINE LUMLEY-SAPANSKI; KENNETH A. JACOBSON

167

Molecular dimensions of poly(ethylene isophthalate) and poly(ethylene naphthalene-2,6-dicarboxylate)  

Microsoft Academic Search

Summary  The rotational isomeric state (RIS) model was used to calculate the molecular dimensions of poly(ethylene isophthalate) (PEI)\\u000a and poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) by introducing new description for aromatic segments and by adopting\\u000a the statistical weight parameters of PET. The mean square dimension ratios ((r2\\u000a 0\\/M)?) of PEN and PEI were 0.653 and 1.167, respectively, and the entanglement molecular weight (Me) of

Ji Ho Youk; Won Ho Jo; Dong Il Yoo

1997-01-01

168

Nanocomposites formed from linear low density polyethylene and organoclays  

Microsoft Academic Search

Polyethylene-clay nanocomposites were prepared by melt compounding various combinations of a maleic anhydride grafted linear low density polyethylene (LLDPE-g-MA), a linear low density polyethylene (LLDPE), and two organoclays. The two types of organoclay were selected to show the effect of the number of alkyl groups attached to the nitrogen of the organic modifier on exfoliation and improvement of mechanical properties.

S. Hotta; D. R. Paul

2004-01-01

169

Catastrophic Failure of Ceramic-Polyethylene Bearing Total Hip Arthroplasty  

Microsoft Academic Search

Complications of ceramic-polyethylene bearing total hip arthroplasty (THA) include osteolysis, loosening, dislocation, and component failure. Catastrophic acetabular component failure involves severe damage to both the polyethylene liner and metal shell. This case study presents the first reported complete wear-through of the acetabular portion of a ceramic-polyethylene arthroplasty presenting as a dislocation and a review of the literature. In this study,

Justin Needham; Travis Burns; Tad Gerlinger

2008-01-01

170

Polyethylene degradation by lignin-degrading fungi and manganese peroxidase  

Microsoft Academic Search

Degradation of high-molecular-weight polyethylene membrane by lignin-degrading fungi, IZU-154, Phanerochaete chrysosporium, and Trametes versicolor, was investigated under various nutritional conditions. IZU-154 showed the most significant polyethylene degradation among\\u000a the three lignin-degrading fungi under nitrogen- or carbon-limited culture conditions. Furthermore, for T. versicolor and P. chrysosporium, the addition of Mn(II) into nitrogen- or carbon-limited culture medium enhanced polyethylene degradation. These results

Yuka Iiyoshi; Yuji Tsutsumi; Tomoaki Nishida

1998-01-01

171

CoCr-Polyethylene Co-Evaporated Films  

NASA Astrophysics Data System (ADS)

This is a report on CoCr-polythylene films synthesized by co-evaporation of CoCr and polyethylene. Through structural and magnetic analyses of CoCr-polyethylene co-evaporated films, it is found that by including amounts of polyethylene, CoCr films become amorphous and their magnetic properties change from hard to soft to superparamagnetic as the amount of polyethylene in the films increases. The results indicate that amorphous metallic alloys can be produced from combinations of metals and polymers as well as by the conventional methods.

Maro, Tsuyoshi; Kitakami, Osamu; Fujiwara, Hideo

1988-04-01

172

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/Ĺ2 and an average distance between grafted chains of 33 Ĺ 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

173

Fabrication and anti-fouling properties of photochemically and thermally immobilized poly(ethylene oxide) and low molecular weight poly(ethylene glycol) thin films.  

PubMed

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)Ĺ(-2) and an average distance between grafted chains of 33Ĺ 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. PMID:21044787

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

2010-10-14

174

Poly(ethylene glycol) conjugated nano-graphene oxide for photodynamic therapy  

Microsoft Academic Search

A novel methoxy-poly(ethylene glycol) modified nano-graphene oxide (NGO-mPEG) was designed and synthesized as a photosensitizer\\u000a (PS) carrier for photodynamic therapy of cancer. NGO with a size below 200 nm was prepared using a modified Hummers’ method.\\u000a NGO was observed by AFM to exhibit a structure with single-layer graphene oxide sheets down to a few nanometers in height.\\u000a Hydrophilic mPEG conjugation

HaiQing Dong; ZhiLei Zhao; HuiYun Wen; FangFang Guo; AiJun Shen; Frank Pilger; Chao Lin; DongLu Shi

2010-01-01

175

Determination of polyethylene glycol in low-density polyethylene by large volume injection temperature gradient packed capillary liquid chromatography  

Microsoft Academic Search

Polyethylene glycol (PEG) 20?000 in low-density polyethylene has been determined using column switching and inverse temperature programming in reversed-phase packed capillary liquid chromatography with evaporative light scattering detection. PEG 20?000 was extracted into water from the polyethylene dissolved in toluene and PEG 35?000 was added as an internal standard (I.S.). The samples in aliquots of 100 ?l were reconcentrated on

I. L. Skuland; T. Andersen; R. Trones; R. B. Eriksen; T. Greibrokk

2003-01-01

176

Comparative study of space charge in aged low-density polyethylene and crosslinked polyethylene  

Microsoft Academic Search

Polyethylene is one of the most widely used polymeric insulators in medium and high voltage power cables. However the importance of space charge distribution and its influence on the electrical aging in this polymer is not fully understood. The very good insulating properties of the material implying very long relaxation times (few days and even longer are usual) and low

M. Carmo Lanca; E. R. Neagu; J. N. Marat-Mendes

2004-01-01

177

Influence of trehalose on conformational and dynamical properties of Poly(Ethylene Oxide) in water  

NASA Astrophysics Data System (ADS)

This paper reports the results of a study on Poly(Ethylene Oxide)/trehalose/water mixtures performed by Photon Correlation Spectroscopy. The chemical structure of the polymer, simpler than that of proteins and its helical conformation in water, constitute a useful starting point for understanding the more complex protein/trehalose/water interactions. The obtained findings support the ``water-replacement'' hypothesis, indicating that a direct polymer-trehalose interaction occurs. Furthermore, trehalose is shown to affect the swelling properties of the polymer with temperature, stabilizing its conformation. .

Villari, V.; Branca, C.; Faraone, A.; Magazů, S.; Maisano, G.; Migliardo, P.

2000-04-01

178

40 CFR 721.10518 - Diethylene glycol, polymer with diisocyanatoalkane, polyethylene glycol monomethyl ether- and...  

Code of Federal Regulations, 2013 CFR

...polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked...polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked...polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked...impurity levels of certain fluorinated impurities.). (b)...

2013-07-01

179

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

Federal Register 2010, 2011, 2012, 2013

...Polyethylene Retail Carrier Bags From the People's Republic...polyethylene retail carrier bags (PRCBs) from the People's...with respect to Dongguan Nozawa Plastics Products Co., Ltd., and...Polyethylene Retail Carrier Bags From the People's...

2011-03-01

180

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

Federal Register 2010, 2011, 2012, 2013

...polyethylene retail carrier bags (PRCBs) from the People's...Polyethylene Retail Carrier Bag Committee and its individual...with respect to Dongguan Nozawa Plastics Products Co., Ltd. and United...Polyethylene Retail Carrier Bags from the People's...

2013-01-02

181

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

Code of Federal Regulations, 2010 CFR

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

2010-01-01

182

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

Code of Federal Regulations, 2010 CFR

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

2009-04-01

183

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

Federal Register 2010, 2011, 2012, 2013

...products. The scope of the order excludes (1) polyethylene bags that are not printed with logos or store names and...with drawstrings made of polyethylene film and (2) polyethylene bags that are packed in consumer packaging with...

2013-08-19

184

75 FR 79336 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...under the countervailing duty order on polyethylene terephthalate film, sheet and strip...through December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

2010-12-20

185

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

Federal Register 2010, 2011, 2012, 2013

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

2010-11-15

186

75 FR 65450 - 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...under the antidumping duty order on polyethylene terephthalate film, sheet and strip...2009 through December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

2010-10-25

187

77 FR 1668 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, in Part, 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...Polypacks on September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

2012-01-11

188

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

189

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

190

75 FR 69400 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...under the countervailing duty order on polyethylene terephthalate film, sheet and strip...through December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

2010-11-12

191

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

192

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

193

77 FR 14501 - 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...the antidumping duty (AD) order on polyethylene terephthalate film, sheet and strip...Polypacks on September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

2012-03-12

194

75 FR 36679 - Polyethylene Retail Carrier Bags From China, Malaysia, and Thailand; Determinations  

Federal Register 2010, 2011, 2012, 2013

...Polyethylene Retail Carrier Bags From China, Malaysia, and Thailand; Determinations On the...polyethylene retail carrier bags from China, Malaysia, and Thailand would be likely to lead...Polyethylene Retail Carrier Bags from China, Malaysia, and Thailand: Investigation...

2010-06-28

195

Proteins  

PubMed Central

An overwhelming array of structural variants has evolved from a comparatively small number of protein structural domains; which has in turn facilitated an expanse of functional derivatives. Herein, I review the primary mechanisms which have contributed to the vastness of our existing, and expanding, protein repertoires. Protein function prediction strategies, both sequence and structure based, are also discussed and their associated strengths and weaknesses assessed.

Sleator, Roy D.

2012-01-01

196

Polyethylene nanofibres with very high thermal conductivities.  

PubMed

Bulk polymers are generally regarded as thermal insulators, and typically have thermal conductivities on the order of 0.1 W m(-1) K(-1). However, recent work suggests that individual chains of polyethylene--the simplest and most widely used polymer--can have extremely high thermal conductivity. Practical applications of these polymers may also require that the individual chains form fibres or films. Here, we report the fabrication of high-quality ultra-drawn polyethylene nanofibres with diameters of 50-500 nm and lengths up to tens of millimetres. The thermal conductivity of the nanofibres was found to be as high as approximately 104 W m(-1) K(-1), which is larger than the conductivities of about half of the pure metals. The high thermal conductivity is attributed to the restructuring of the polymer chains by stretching, which improves the fibre quality toward an 'ideal' single crystalline fibre. Such thermally conductive polymers are potentially useful as heat spreaders and could supplement conventional metallic heat-transfer materials, which are used in applications such as solar hot-water collectors, heat exchangers and electronic packaging. PMID:20208547

Shen, Sheng; Henry, Asegun; Tong, Jonathan; Zheng, Ruiting; Chen, Gang

2010-03-07

197

Self-Healing of Polyethylene Oxide  

NASA Astrophysics Data System (ADS)

Autonomic self-healing is expected to enhance the lifetime of polymeric materials, resins, and composites subjected to long term mechanical stresses. The self-healing process is initiated by the rupture of some polyurea-formaldehyde microcapsules filled with monomer. The self-healing polymer is actually a compound containing microcapsules filled with monomer and catalyst particles. The monomer released from these broken microcapsules is diffusing within the polymer, reacting with the catalyst and starting a polymerization reaction. This new polymer, growing within the propagating crack, stops the mechanical failure. While the process is pretty slow (timescale of the order of 10 to 100 s), there are many important technological applications that would benefit from the availability of self-healing polymers. We report about the addition of self-healing capabilities to polyethylene oxide by using polyurea formaldehyde microcapsules filled with dicyclopentadiene and first generation Grubbs catalysts. Details regarding the physical and chemical steps used to add self-healing capabilities to polyethylene oxide will be presented. Self-healing efficiency was assessed by fatigues tests.

Magdalena Chipara, Dorina; Flores, Maritza; Puente, Nancy; Lozano, Karen

2011-03-01

198

Polyethylene nanofibres with very high thermal conductivities  

NASA Astrophysics Data System (ADS)

Bulk polymers are generally regarded as thermal insulators, and typically have thermal conductivities on the order of 0.1 W m-1 K-1 (ref. 1). However, recent work suggests that individual chains of polyethylene-the simplest and most widely used polymer-can have extremely high thermal conductivity. Practical applications of these polymers may also require that the individual chains form fibres or films. Here, we report the fabrication of high-quality ultra-drawn polyethylene nanofibres with diameters of 50-500 nm and lengths up to tens of millimetres. The thermal conductivity of the nanofibres was found to be as high as ~104 W m-1 K-1, which is larger than the conductivities of about half of the pure metals. The high thermal conductivity is attributed to the restructuring of the polymer chains by stretching, which improves the fibre quality toward an `ideal' single crystalline fibre. Such thermally conductive polymers are potentially useful as heat spreaders and could supplement conventional metallic heat-transfer materials, which are used in applications such as solar hot-water collectors, heat exchangers and electronic packaging.

Shen, Sheng; Henry, Asegun; Tong, Jonathan; Zheng, Ruiting; Chen, Gang

2010-04-01

199

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

200

Polyethylene reinforced with keratin fibers obtained from chicken feathers  

Microsoft Academic Search

Polyethylene-based composites were prepared using keratin fibers obtained from chicken feathers. Fibers of similar diameter but varying aspect ratio were mixed into low-density polyethylene (LDPE) using a Brabender mixing head. From uniaxial tensile testing, an elastic modulus and yield stress increase of the composite over the virgin polymer was observed over a wide range of fiber loading. Scanning electron microscopy

Justin R. Barone; Walter F. Schmidt

2005-01-01

201

Elastic and thermal expansion anisotropy of oriented linear polyethylene  

Microsoft Academic Search

A two-phase composite laminate model is proposed for representing biaxially oriented sheets of linear polyethylene. Thermoelastic analysis of the model yields predictions of the complete elastic and thermal expansion anisotropy. These predictions are compared with experimental measurements of elastic compliance and thermal expansivity obtained with the same oriented sheets. Using only one adjustable parameter (Poisson's ratio of non-crystalline linear polyethylene),

C. P. Buckley

1974-01-01

202

Development and tests of extruded polyethylene insulated superconducting cable  

Microsoft Academic Search

A superconducting power cable which has a similar structure to the conventional extruded polyethylene cable is proposed. The rated voltage and current are 20 kV and 2 kA, respectively. The design utilizes the excellent electrical properties of polyethylene at cryogenic temperatures and separate helium coolant from the electrical insulation. The outer superconductor layers for magnetic shielding are eliminated for the

M. Kosaki; M. Nagao; Y. Mizuno; K. Horii; N. Shimizu

1988-01-01

203

Calorimetric investigation of the tensile deformation of polyethylene  

Microsoft Academic Search

A calorimetric apparatus for investigating the thermal effects associated with tensile deformation is described. The results of calorimetric measurements made on high- and low-density polyethylene during the deformation process are presented. It is shown that on the interval of strains and loading rates investigated the deformation of polyethylene is energetic in character.

Yu. M. Molchanov; G. A. Molchanova

1970-01-01

204

Effect of polyethylene particles on human osteoblastic cell growth  

Microsoft Academic Search

In this study, we have analyzed the direct effect of ultrahigh molecular weight polyethylene (polyethylene) on the osteoblastic cell growth in primary cultures. The cells were cultured from human bone samples obtained during reconstructive joint surgery. When cell cultures reached confluence (4–6 weeks) they were separated into three subcultures. One subculture was without particle addition (plain culture). In the other

M. E. Mart??nez; S. Medina; M. T. del Campo; J. A. Garc??a; Ana Rodrigo; L. Munuera

1998-01-01

205

Proteins  

NSDL National Science Digital Library

Laboratory manual and supplemental resources that were developed for a college laboratory course in protein purification. The enzyme, Beta-galactosidase, is purified in two steps, with analysis and verification of results. Course materials are divided into four units: Why Proteins, Assays, The Purification Process, and Analysis and Verification. Powerpoint lectures and study guides are provided.

Seidman, Lisa A.; Mowery, Jeanette

2009-10-01

206

Polyethylene glycol: a game-changer laxative for children.  

PubMed

Constipation is a common problem in children worldwide. It can also be a chronic problem persisting for many months to years. Successful treatment of constipation requires long-term use of laxatives. Commonly used laxatives in children include milk of magnesia, lactulose, mineral oil, and polyethylene glycol. Compared with other laxatives, polyethylene glycol (with and without electrolytes) is a relatively new laxative used during the last decade. Recent studies report excellent efficacy and safety of polyethylene glycol for the long-term treatment of constipation in children. Because of excellent patient acceptance, polyethylene glycol has become a preferred choice of laxative for many practitioners. This article reviews the recently published pediatric literature on biochemistry, efficacy, safety, patient acceptance, and pharmacoeconomics of polyethylene glycol. PMID:23591910

Alper, Arik; Pashankar, Dinesh S

2013-08-01

207

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

208

Thermal transport in polyethylene and at polyethylene-diamond interfaces investigated using molecular dynamics simulation  

Microsoft Academic Search

The thermal conductances across covalently bonded interfaces between oriented single crystal diamond and completely aligned polyethylene chains are determined for the three principal orientations of diamond. The calculated thermal conductances, which range over 690-930 MW m-2 K-1, are consistent with those of other strongly bonded interfaces. These results suggest that the experimental interfacial conductances across hard-soft interfaces can be quite

Boris Ni; Taku Watanabe; Simon R. Phillpot

2009-01-01

209

Polyethylene glycol-induced mammalian cell hybridization: Effect of polyethylene glycol molecular weight and concentration  

Microsoft Academic Search

The effects of polyethylene glycol (PEG) molecular weight and concentration on mammalian cell hybridization were studied. The peak hybridization-inducing activity with all grades of PEG from 400–6000 was found to occur in the concentration range of 50–55%. However, changes in concentration were seen to have different quantitative effects with different grades of PEG. For monolayer fusions, PEG 1000 at 50%

Richard L. Davidson; Kathleen A. O'Malley; Thomas B. Wheeler

1976-01-01

210

Water Potential of Aqueous Polyethylene Glycol  

PubMed Central

Water potential (??) values were determined for aqueous colloids of four molecular sizes of polyethylene glycol (PEG) using freezing-point depression and vapor-pressure deficit methods. A significant third-order interaction exists between the method used to determine ??, PEG molecular size, and concentration. At low PEG concentrations, freezing-point depression measurements result in higher (less negative) values for ?? than do vapor-pressure deficit measurements. The reverse is true at high concentrations. PEG in water does not behave according to van't Hoff's law. ?? is related to molality for a given PEG but not linearly. Moreover, ?? varies with the molecular size of the PEG. It is suggested that the ?? of PEG in water may be controlled primarily by the matric forces of ethylene oxide subunits of the PEG polymer. The term matricum is proposed for PEG in soil-plant-water relation studies.

Steuter, Allen A.; Mozafar, Ahmad; Goodin, Joe R.

1981-01-01

211

Polyethylene Terephthalate May Yield Endocrine Disruptors  

PubMed Central

Background Recent reports suggest that endocrine disruptors may leach into the contents of bottles made from polyethylene terephthalate (PET). PET is the main ingredient in most clear plastic containers used for beverages and condiments worldwide and has previously been generally assumed not to be a source of endocrine disruptors. Objective I begin by considering evidence that bottles made from PET may leach various phthalates that have been putatively identified as endocrine disruptors. I also consider evidence that leaching of antimony from PET containers may lead to endocrine-disrupting effects. Discussion The contents of the PET bottle, and the temperature at which it is stored, both appear to influence the rate and magnitude of leaching. Endocrine disruptors other than phthalates, specifically antimony, may also contribute to the endocrine-disrupting effect of water from PET containers. Conclusions More research is needed in order to clarify the mechanisms whereby beverages and condiments in PET containers may be contaminated by endocrine-disrupting chemicals.

Sax, Leonard

2010-01-01

212

Electrical conductivity effects in polyethylene terephthalate films  

NASA Astrophysics Data System (ADS)

Electrical conductivity effects in biaxially stretched polyethylene terephthalate (PET) films of 6 ?m thickness and 68% degree of crystallinity were investigated by means of dielectric relaxation spectroscopy in the frequency range 10-2-106 Hz and at temperatures higher than the glass transition temperature (~85 °C) up to 190 °C. The formalisms of complex permittivity, electric modulus, and impedance were employed to analyze the experimental data. The results are discussed in terms of dc conductivity, conductivity current relaxation, interfacial Maxwell-Wagner-Sillars polarization, ? peak, space-charge polarization, and electrode polarization. They are compared with the predictions of models for the electrical and dielectric properties of ion-conducting polymers. The dc conductivity values determined from dc measurement, from ac conductivity plots and from complex impedance plots agree well with each other. Their temperature dependence is described by the Vogel-Tammann-Fulcher equation and classifies PET as a fragile system.

Neagu, E.; Pissis, P.; Apekis, L.

2000-03-01

213

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

214

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

215

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

216

Simulation of melting in crystalline polyethylene  

NASA Astrophysics Data System (ADS)

We carry out a molecular dynamics simulation of the first stages of constrained melting in crystalline polyethylene (PE). When heated, the crystal undergoes two structural phase transitions: from the orthorhombic (O) phase to the monoclinic (M) phase, and then to the columnar (C), quasi-hexagonal, phase. The M phase represents the tendency to the parallel packing of planes of PE zigzags, and the C phase proves to be some kind of oriented melt. We follow both the transitions O-->M and M-->C in real time and establish that, at their beginning, the crystal tries (and fails) to pass into the partially ordered phases similar to the RI and RII phases of linear alkanes, correspondingly. We discuss the molecular mechanisms and driving forces of the observed transitions, as well as the reasons why the M and C phases in PE crystals substitute for the rotator phases in linear alkanes.

Zubova, E. A.; Balabaev, N. K.; Musienko, A. I.; Gusarova, E. B.; Mazo, M. A.; Manevitch, L. I.; Berlin, A. A.

2012-06-01

217

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

218

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

2013-01-17

219

Grafting of dermatan sulfate on polyethylene terephtalate to enhance biointegration.  

PubMed

The aim of the present study was to achieve the immobilization of dermatan sulfate (DS) on polyethylene terephthalate (PET) surfaces and to evaluate its biocompatibility. DS obtained from the skin of Scyliorhinus canicula shark was immobilized via carbodiimide on knitted PET fabrics, modified with carboxyl groups. PET-DS characterization was performed by SEM, ATR-FTIR and contact angle measurements. Biocompatibility was evaluated by investigating plasma protein adsorption and endothelial cell proliferation, as well as by subcutaneous implantations in rats. The results indicated that DS immobilization on PET was achieved at ~8 ?g/cm˛. ATR-FTIR evidenced the presence of sulfate groups on the PET surface. In turn, contact angle measurements indicated an increase in the surface wettability. DS immobilization increased albumin adsorption on the PET surface, whereas it decreased that of fibrinogen. In vitro cell culture revealed that endothelial cell proliferation was also enhanced on PET-DS. Histological results after 15 days of subcutaneous implantation showed a better integration of PET-DS samples in comparison to those of nonmodified PET. In summary, DS was successfully grafted onto the surface of PET, providing it new physicochemical characteristics and biological properties for PET, thus enhancing its biointegration. PMID:21548062

Dhahri, Manel; Abed, Aicha; Lajimi, Ramzi Hadj; Mansour, Mohamed Ben; Gueguen, Virginie; Abdesselem, Saber Ben; Chaubet, Frederic; Letourneur, Didier; Meddahi-Pellé, Anne; Maaroufi, Raoui M

2011-05-04

220

Densities and viscosities of polyethylene glycol + salt + water systems at 20 C  

SciTech Connect

Partitioning of biomaterials utilizing aqueous two-phase systems is a new and powerful separation technique with industrial potential. The technique has been applied in biochemistry, biology, and biochemical engineering to separate and purify biological products, biomaterials, cell organs, proteins, and enzymes from the complex mixtures in which they are produced. Densities and viscosities of polyethylene glycol (PEG), K{sub 3}PO{sub 4}, or (NH{sub 4}){sub 2}SO{sub 4} aqueous single-phase and two-phase systems have been measured at 20 C. The densities and viscosities were correlated with the compositions and the tie line lengths of the aqueous two-phase systems.

Mei, L.H.; Lin, D.Q.; Zhu, Z.Q.; Han, Z.X. [Zhejiang Univ., Hangzhou (China). Dept. of Chemical Engineering

1995-11-01

221

Accurate delivery of single biomolecules by polyethylene glycol coated submicrometer pipettes  

NASA Astrophysics Data System (ADS)

There is a great interest to quantitatively manipulate, separate, and deliver low concentrations or even single biomolecules in submicrometer-sized channels. We report the use of cross-linked four-star polyethylene glycol (PEG) as a new coating technique for microchannels. PEG-coating efficiently reduces the electroosmotic flow (EOF) and non-specific adsorption to the glass walls. Our results demonstrate that individual fluorescently labeled hydrophobic cell adhesion proteins (fibronectin molecules) can be drawn through PEG-coated submicrometer pipettes in aqueous solution by electrokinetic forces without the addition of detergents or other additives which potentially deteriorate the activity and specificity of biomolecules.

Park, Chong-Woo; Knemeyer, Jens-Peter; Marmé, Nicole; Möller, Martin; Spatz, Joachim; Wolfrum, Jürgen; Sauer, Markus

2004-05-01

222

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

223

Durability of Polyethylene-Based Geomembranes in Aggressive Liquid Media.  

National Technical Information Service (NTIS)

Durability of a polyethylene based geomembrane was investigated in three carefully selected liquids which simulated common chemicals in transportation and waste deposit environments. The degradation processes were accelerated by a moderate increase in tem...

I. Jakubowicz U. Johansson

1995-01-01

224

Evaluation of Expanded Bead Polyethylene Foam Cushioning For Packaging.  

National Technical Information Service (NTIS)

Expanded Bead Molded Polyethylene Foam Cushioning Material was evaluated for its static and dynamic characteristics. It was determined that the material meets the compression set and compressive strength requirements of Type I material of PPP-C-1752A, 'Cu...

R. V. Brown

1979-01-01

225

Ion Implantation to Reduce Wear on Polyethylene Prosthetic Devices.  

National Technical Information Service (NTIS)

Researchers studied the use of ion implantation to improve the wear performance of ultra high molecular weight polyethylene (UHMWPE). UHMWPE samples were implanted with high energy ions, tested for wear performance, and compared to unimplanted control sam...

1991-01-01

226

Temperature Dependence of Polyethylene Elastic Moduli using Molecular Simulations  

NASA Astrophysics Data System (ADS)

A novel result is presented for elastic moduli calculation of the semi-crystalline polyethylene interphase. Further, a description of timescales is introduced as an illustration of the alpha-relaxation phenomenon. Off-lattice polyethylene is described by a realistic, united atom force field, which includes torsional contributions. The interphase is modeled as a metastable disordered region constrained between two static crystalline layers and consists of bridge, loop and tail populations of varying chain length. Separate temperatures are simulated in the isochoric/isothermal ensemble with Monte Carlo integration and are coupled by parallel tempering. Elastic moduli are calculated by considering energetic and entropic contributions, the latter of which are indirectly obtained through virial pressure calculations. The interphase region of real polyethylene, characterized by density, order and energy profiles, is compared to earlier work on freely rotating polyethylene-like systems.

in't Veld, Pieter; Rutledge, Gregory

2003-03-01

227

Dewatering of Mineral Waste Using the Flocculant Polyethylene Oxide.  

National Technical Information Service (NTIS)

The bulletin summarizes the results of Bureau of Mines investigations of a technique for dewatering clay waste that consists of flocculation with polyethylene oxide (PEO) followed by screening of the resulting flocs. Results of laboratory tests and small-...

B. J. Scheiner A. G. Smelley D. A. Stanley

1985-01-01

228

Fractionation Studies of Polyethylene Using DSC-Technique.  

National Technical Information Service (NTIS)

This review will discuss work done on both well characterized LDPE, LLDPE and VLLDPE resins as well as on commercially available 'metallocene' type polyethylenes and corresponding test grades produced at Helsinki University of Technology (HUT) and at Bore...

P. Starck

1994-01-01

229

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 ...

230

Evaluation of the Compressed Ring Test for Polyethylene Gas Piping.  

National Technical Information Service (NTIS)

Properties of mass produced polyethylene pipe may be affected by changes in polymerization, blending, compounding and extrusion conditions from one production run to the next. The Compressed Ring Test has been proposed as a relatively simple and inexpensi...

A. Lustiger M. J. Cassidy R. L. Markham M. M. Epstein

1983-01-01

231

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

232

DISSIPATION OF FIELD APPLIED HERBICIDES FROM LOW DENSITY POLYETHYLENE MULCH  

Technology Transfer Automated Retrieval System (TEKTRAN)

Field studies evaluated dissipation of herbicides from low density polyethylene mulch (LDPM). Herbicide dissipation was measured under dry conditions and following irrigation events. Halosulfuron, paraquat, carfentrazone, glyphosate, and oxyfluorfen were applied to black 1.5-mil LDPM at concentrat...

233

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

234

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

235

Acquired biodegradability of polyethylenes containing pro-oxidant additives  

Microsoft Academic Search

Biodegrability of high density polyethylene film (HDPE) and low density polyethylene film (LDPE) both containing a balance of antioxidants and pro-oxidants was studied with defined microbial strains particularly with Rhodococcus rhodochrous and Nocardia asteroides in mineral medium. After an abiotic pre-treatment consisting of photooxidation and thermo-oxidation corresponding to about 3 years of outdoor weathering the samples were inoculated, incubated up

Marek Koutny; Martine Sancelme; Catherine Dabin; Nicolas Pichon; Anne-Marie Delort; Jacques Lemaire

2006-01-01

236

Simple EOS for branched (low-density) polyethylene  

SciTech Connect

A simple equation of state (EOS) for branched (low-density) polyethylene was generated and added to the T-4 Sesame EOS Library as material number 7171. This EOS is intended to replace an earlier EOS (material number 7170) for this substance. This new EOS for polyethylene reproduces the experimental shock Hugoniot data for the initial state density rho/sub o/ = 0.916 g/cm/sup 3/ or Mg/m/sup 3/.

Dowell, F.

1982-10-01

237

Structure–Property Relationships in Low-Density Polyethylene  

Microsoft Academic Search

Modern techniques were adopted and utilized for molecular-weight characterization of commercial low-density (branched) polyethylenes. The index of long-chain branching was uniquely related to that of molecular-weight dispersion, Dn. Two groups of low-density polyethylenes were visualized, differing in width of MW distribution and in the branching index. An attempt was made to relate the flow properties, melt-flow index (MFI) and intrinsic

Arie Ram; Joseph Miltz

1972-01-01

238

Slurry erosion behaviors of basalt filled low density polyethylene composites  

Microsoft Academic Search

In this study, slurry erosion behaviors of basalt filled low density polyethylene composites were investigated. Pure low density polyethylene and four different compositions of the composites 10wt.%, 30wt.%, 50wt.% and 70wt.% basalt were used in the study. Slurry wear, tensile strain, hardness and fracture toughness tests were performed on the samples. Samples turns in the abraded slurry media including 50wt.%

Akin Akinci; Ediz Ercenk; Senol Yilmaz; Ugur Sen

2011-01-01

239

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

240

Wear Analysis in THA Utilizing Oxidized Zirconium and Crosslinked Polyethylene  

Microsoft Academic Search

Oxidized zirconium, a material with a ceramic surface on a metal substrate, and highly cross-linked polyethylene are two materials\\u000a developed to reduce wear. We measured in vivo femoral head penetration in patients with these advanced bearings. We hypothesized\\u000a the linear wear rates would be lower than those published for cobalt-chrome and standard polyethylene. We retrospectively\\u000a reviewed a select series of

Kevin L. Garvin; Curtis W. Hartman; Jimmi Mangla MBBS; Nathan Murdoch; John M. Martell

2009-01-01

241

Adsorption of Polypropylene and Polyethylene on Liquid Chromatographic Column Packings  

Microsoft Academic Search

A group of zeolites and a 3D nanoporous metal-organic material RPM-1 were tested as column packings for adsorption of isotactic polypropylene and linear polyethylene from dilute solutions. It was found that polyethylene is fully or partially retained from thermodynamically good solvents (1,1,2,2-tetrachloroethylene, 1,4-dimethylbenzene, diphenylether, 1,2-dichlorobenzene and 1,3-dichlorobenzene) at temperatures of 115 °C or 140 °C, when a specific type of

T. Macko; J. F. Denayer; H. Pasch; L. Pan; J. Li; A. Raphael

2004-01-01

242

Launch Vehicle with Combustible Polyethylene Case Gasification Chamber Design Basis  

NASA Astrophysics Data System (ADS)

A single-stage launch vehicle equipped with a combustible tank shell of polyethylene and a moving propulsion plant is proposed. The propulsion plant is composed of a chamber for the gasification of the shell, a compressor of pyrolysed polyethylene and a magnetic powder obturator. It is shown that the “dental” structure of the gasification chamber is necessary to achieve the necessary contact area with the polyethylene shell. This conclusion is drawn from consideration of the thermo- physical properties of polyethylene, calculating quasisteady temperature field in the gasification chamber, estimating gasification rate of polyethylene, launch vehicle shortening rate and area of gasification. Experimental determination of the gasification rate is described. The gasification chamber specific mass as well as the propulsion plant weight-to-thrust ratio are estimated under some assumptions concerning the obturator and compressor. Combustible launch vehicles are compared with conventional launch vehicles taking into consideration their payload mass ratios. Combustible launchers are preferable as small launchers for micro and nano satellites. Reusable versions of such launchers seem suitable if polyethylene tank shells filled with metal or metal hydride fine dusts are used.

Yemets, V.

243

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

244

Toughening effect of maleic anhydride grafted linear low density polyethylene on linear low density polyethylene  

Microsoft Academic Search

The blend of linear low density polyethylene (LLDPE) and maleic-anhydride grafted LLDPE with the grafting degree of 1.3% and\\u000a the gel content of 27.0% (designated as LLDPE\\/MA-PE) was melt-compounded. Their thermal, rheological, and mechanical properties\\u000a were studied. The crystallization temperature and crystallization rate of LLDPE\\/MA-PE blends increase due to the nucleation\\u000a of MA-PE, their crystallinity is between those of LLDPE

Le-Ping Huang; Xing-Ping Zhou; Wei Cui; Xiao-Lin Xie; Shen-Yi Tong

2008-01-01

245

Crystallization and morphologies of linear low density polyethylene and its blends with high density polyethylene  

NASA Astrophysics Data System (ADS)

Knowledge of the kinetics of polymer crystallization is important in controlling polymer forming processes, while knowledge of the resulting microstructure is important in predicting the ultimate mechanical properties of the material. It is also known that processing parameters will affect the ultimate morphology and properties of the sample. The crystallization, morphology and mechanical properties of a specific linear low density polyethylene copolymer and its blends with two high density polyethylene homopolymers of differing molecular weight are investigated. Several new techniques are employed in an effort to examine the effect of crystallization kinetics on the development of morphology. These include the simultaneous processing of thin film and bulk samples, and the use of atomic force microscopy to generate images of the microstructure. Thermal properties, and melting and crystallization behaviors are examined with differential scanning calorimetry. The mechanical properties of the blends, as a function of crystallization temperature and blend content, are examined through the use of microhardness testing, and nanoindentation testing via the atomic force microscope. The former provides hardness values, which are related to both the elastic moduli and yield strengths of the samples; the latter technique provides a new method for deriving the relative elastic moduli of the component polymers, as well as for specific structures within the morphology. This provides a novel means of determining the distribution of the component polymers within the blend. The rates of crystallization for the blends and the component polymers are analyzed with respect to the Hoffman Kinetic Theory for the crystallization of polymers to determine whether the existing theory is adequate for describing the behaviors of the blends. It has been determined that the blend systems form a co-crystalline microstructure; however, significant amounts of linear low density polyethylene are excluded from the co-crystals. Models to describe the blend behaviors over a broad range of crystallization temperatures have been proposed. It has been determined that the Hoffman Theory for the crystallization of polymers does not adequately describe the growth of the linear low density polyethylene copolymer or its blends.

Bischel, Marsha Stalker

246

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

247

Purification of antibodies by precipitating impurities using Polyethylene Glycol to enable a two chromatography step process.  

PubMed

The purification of antibodies by precipitating impurities using Polyethylene Glycol (PEG) was assessed with the objective of developing a two chromatography column purification process. A PEG precipitation method was evaluated for use in the industrial purification of recombinant monoclonal antibodies (MAbs). Effective and robust precipitation conditions including PEG concentration, pH, temperature, time, and protein concentration were identified for several different MAbs. A recovery process using two chromatography steps in combination with PEG precipitation gave acceptable yield and purity levels for IgG1 and IgG4 antibodies with a broad range of isoelectric points (pI). PEG precipitation removed host cell proteins (HCPs), high molecular weight species (HMWS), leached Protein A ligand, and host cell DNA to acceptable levels when run under appropriate conditions, and some endogenous virus removal was achieved. PMID:24036248

Giese, Glen; Myrold, Adam; Gorrell, Jeffrey; Persson, Josefine

2013-08-28

248

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

249

UV stability and radiation-crosslinking of linear low density polyethylene and low density polyethylene for greenhouse applications  

Microsoft Academic Search

Ultraviolet (UV) radiation stability and ?-radiation crosslinking of linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) for greenhouse film applications was investigated. Various combinations of primary antioxidant (i.e. Irganox 1010), secondary antioxidant (i.e. Irgafos 168), UV absorber (i.e. Chimassorb 81) and hindered amine light stabilizer (HALS) were used to prepare thin PE films (60 ?m thick). The films

Ahmed A Basfar; K. M Idriss Ali; S. M Mofti

2003-01-01

250

Natural weathering test for films of various formulations of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE)  

Microsoft Academic Search

Natural (outdoor) weathering test was performed to investigate the UV stability of thin films (0.06mm) of linear low density polyethylene (LLDPE) and low density polyethylene (LDPE). The PE films were prepared from various formulations of LLDPE and LDPE resins. Some of these films contained a single high molecular mass HALS only, along with a primary antioxidant (i.e. Irganox 1010) and

A. A. Basfar; K. M. Idriss Ali

2006-01-01

251

Kinetic approach to radiation-induced grafting in the polyethylene-styrene system. IV. Comparison between high density polyethylene and low density polyethylene. [Gamma radiation  

SciTech Connect

The investigation method reported in earlier articles was applied to preirradiation methods of the reaction of low-density polyethylene (LDPE) in liquid and vapor and compared with high-density polyethylene (HDPE). Monomer concentrations during reactions and monomer feed rates were determined gravimetrically. Increasing patterns of the degree of grafting were obtained and compared. Monomer concentration during the reactions was lower in LDPE than HDPE and radical decay was more rapid in LDPE. A model calculation was applied to this experiment and a schematic explanation was attempted. The differences between the reaction mechanisms of HDPE and LDPE are explained.

Imai, M.

1981-07-01

252

The effect of polyethylene glycol on the characteristics of kenaf cellulose/low-density polyethylene biocomposites.  

PubMed

Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites. PMID:20417660

Tajeddin, Behjat; Rahman, Russly Abdul; Abdulah, Luqman Chuah

2010-04-24

253

Analysis of polyethylene wear in plain radiographs  

PubMed Central

Background and purpose Two-dimensional computerized radiographic techniques are frequently used to measure in vivo polyethylene (PE) wear after total hip arthroplasty (THA), and several variables in the clinical set-up may influence the amount of wear that is measured. We compared the repeatability and concurrent validity of linear PE wear on plain radiographs using the same software but a different number of radiographs. Methods We used either 1, 2, or 6 anteroposterior (AP) hip radiographs of 11 patients from a clinical THA series with 12 years of follow-up, and measured the PE wear with the software PolyWare 3D Pro. Repeatability within and concurrent validity between the different numbers of radiograph strategies were assessed using limits of agreement (LOAs) and bias. Results Observed median wear (range) in mm was 3.4 (1.6–4.6), 2.3 (0.7–4.9), and 4.0 (2.6–6.2) for the 1-, 2-, and 6-radiograph strategies. For repeatability, no bias (p > 0.41) was observed. LOAs around the bias were ± 0.6, ± 0.4, and ± 1.2 mm for the 1-, 2-, and 6-radiograph strategies. For concurrent validity, a bias (± LOA) between all pairwise comparisons was observed (p < 0.02) with 0.8 mm (± 2.5) between the 1- and 2-radiograph strategies, 1.0 mm (± 2.2) between the 1- and 6-radiograph strategies, and 1.8 mm (± 1.2) between the 2- and 6-radiograph strategies. Interpretation The number of radiographs used for wear measurement with a shadow-casting analysis method on plain AP radiographs influences the amount of linear wear measured. Results of PE wear obtained with PolyWare in studies using a different number of radiographs are not comparable.

2009-01-01

254

Carbide process picked for Chinese polyethylene plant  

SciTech Connect

Union Carbide (Danbury, CT) is set to sign up its eighth polyethylene (PE) license in China. The company has been selected to supply its Unipol technology to Jilin Chemical Industrial Corp. (JCIC) for a 100,000-m.t./year linear low-density PE (LLDPE) plant at Jilin. The plant will form part of a $2-billion petrochemical complex, based on a 300,000-m.t./year ethylene unit awarded to a consortium made up of Samsung Engineering (Seoul) and Linde. A 10,000-m.t./year butene-1 unit will also be built. Toyo Engineering, Snamprogetti, Mitsubishi Heavy Industries, and Linde are competing for the contract to supply the LLDPE plant. The signing is expected this spring. Two contenders are vying to supply an 80,000-m.t./year phenol plant for JCIC. They are Mitsui Engineering, offering the Mitsui Petrochemical process, and Chisso, with UOP technology. Four Unipol process PE plants are under construction in China and three are in operation. At Guangzhou, Toyo Engineering is building a 100,000-m.t./year plant, due onstream in 1995, while Snamprogetti is to finish construction of two plants in the same year at Zhonguyan (120,000 m.t./year) and at Maoming (140,000 m.t./year). The Daquing Design Institute is responsible for the engineering of a 60,000-m.t./year Unipol process PE plant, expected onstream early in 1995. Existing Unipol process PE plants are located in Qilu (60,000 m.t./year LLDPE and 120,000 m.t./year HDPE) and at Taching (60,000 m.t./year HDPE).

Alperowicz, N.

1993-02-10

255

Fibrovascularization and osteogenesis in high-density porous polyethylene implants.  

PubMed

High-density porous polyethylene (HDPP) has been extensively used in craniofacial reconstructions with high-level success and minimal complications. It is known for its biocompatibility and satisfactory stability in the receptor bone area, presenting only a few reports of mobility and infection. In the current study, attention was given to the interface area between HDPP and bone surface to analyze fibrous and bone tissue formation and ingrowth into the pores of the material placed in the mandible of rabbits. Twelve male New Zealand rabbits underwent surgical procedure to receive bilateral HDPP implants in buccal face of dentate mandibular alveolar process, fixed with titanium screws. After 7, 14, 45, and 90 days, the animals were killed, and the specimens were retrieved for histologic and immunohistochemical analyses. No implant loss or infection was detected at the retrieval of the specimens. The microscopic analysis presented satisfactory integration of the material to the bone surface, with new bone formation from the receptor bed and inside the pores of the material, observed from the 15th day. After 90 days, remodeling bone and fibrous tissue was seen in the interface region. Among some of the pores, mature lamellar bone was present. Immunohistochemistry pointed out a moderate expression either to Core binding factor protein 1/RUNX2 or to vascular endothelial growth factor for early periods evaluated, that is, 7 and 15 days after surgery. These results confirm the osteoconductive behavior and high biocompatibility of the material, associated to its adequate immobilization, leading to its lifelong presence in human biologic system. PMID:19553849

Oliveira, Renato Victor; de Souza Nunes, Leandro Soeiro; Filho, Hugo Nary; de Andrade Holgado, Leandro; Ribeiro, Daniel Araki; Matsumoto, Mariza Akemi

2009-07-01

256

Photochemical modification of polyethylene terephthalate surface  

NASA Astrophysics Data System (ADS)

The prospect of obtaining desired surface-mediated characteristics while retaining bulk-mediated physical properties and avoiding potential environmental issues with wet chemical technology lends considerable appeal to photochemical approaches to surface modification. We undertook a combined experimental and computational approach to investigate the effect of deep UV irradiation on the polyethylene terephthalate (PET) surface. Its response to 172 nm UV from a xenon examiner lamp in the absence of oxygen was characterized with X-ray Photoelectron Spectroscopy (XPS), Time of Flight/Secondary Ion Mass Spectrometry (ToF/SIMS), transmission infrared spectroscopy (IR), and Atomic Force Microscopy (AFM). The surface chemistry details suggested that the primary photochemical reactions involved a Norrish type I based decarbonylation and a Norrish type II process yielding terminal carboxylic acid groups, consistent with the possible photochemistry from n-pi* type lowest singlet excited states of PET according to the computational modeling results. By directly populating n-pi* type excited states, 172 nm UV promoted effective surface photochemistry of PET with further helps from the high UV absorptivity and the high surface mobility of the molecules. Utilizing this active surface radical chemistry, a new grafting strategy was developed to impart desirable functional properties to the surface. A broad range of grafting chemicals can be employed in their vapor forms, demonstrated with an alkene or an alkane. Surface analysis with XPS, ToF/SIMS, AFM, and water contact angle measurements confirmed the effectiveness of the approach, supporting the notion of the surface radical initiated processes. A potentially useful anti-stain/soil coating was developed by grafting with a fluorocarbon species. Surface analysis suggested that the grafted fluorocarbon formed a nano-scale self-assembled monolayer. The coating had a similar water contact angle as that of a pure fluoropolymer but a better oil repellency due to the special molecular orientation in the graft layer. A potential antimicrobial application was demonstrated with amine chemicals. Structure characterization and computational modeling results suggested that the photochemistry of the UV active grafting chemicals also played an important role in the grafting process. A double bond structure in the amine species protected the amine functional groups and the resulting coating demonstrated antimicrobial activity against E. coli.

Zhu, Zhengmao

257

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

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...2\\ See Polyethylene Terephthalate Film, Sheet, and Strip...1332 (Ct. Int'l Trade 2013); Polyethylene Terephthalate Film, Sheet, and...

2013-08-23

258

75 FR 75454 - Polyethylene Retail Carrier Bags From Thailand: Extension of Time Limit for the 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. See Polyethylene Retail Carrier Bags From...

2010-12-03

259

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

260

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

261

Space radiation transport properties of polyethylene-based composites.  

PubMed

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. PMID:15644352

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

2004-11-01

262

Alteration in Rheological Properties of Polyethylene by Extrusion Processing  

NASA Astrophysics Data System (ADS)

The effect of processing temperature in a single-screw extruder on molecular characteristics of polyethylene (PE) was studied by employing additive-free low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) for extrusion coating. It was indicated that melt elasticity is enhanced by applied extrusion processing at high temperature, suggesting that long-chain branches are generated by cross-linking reaction. On the contrary, thermal analyses revealed that there is no change in the distribution of short-chain branches by extrusion processing. Further, chain scission of PE took place predominantly above 320°C. Meanwhile at low temperature, the processing history decreased the melt elasticity. This is attributed to shear modification phenomenon.

Ono, Kazuya; Yamaguchi, Masayuki

263

Gelation characteristics and osteogenic differentiation of stromal cells in inert hydrolytically degradable micellar polyethylene glycol hydrogels.  

PubMed

The use of poly(ethylene glycol) (PEG) hydrogels in tissue engineering is limited by their persistence in the site of regeneration. In an attempt to produce inert hydrolytically degradable PEG-based hydrogels, star (SPELA) poly(ethylene glycol-co-lactide) acrylate macromonomers with short lactide segments (<15 lactides per macromonomer) were synthesized. The SPELA hydrogel was characterized with respect to gelation time, modulus, water content, sol fraction, degradation, and osteogenic differentiation of encapsulated marrow stromal cells (MSCs). The properties of SPELA hydrogel were compared with those of the linear poly(ethylene glycol-co-lactide) acrylate (LPELA). The SPELA hydrogel had higher modulus, lower water content, and lower sol fraction than the LPELA. The shear modulus of SPELA hydrogel was 2.2 times higher than LPELA, whereas the sol fraction of SPELA hydrogel was 5 times lower than LPELA. The degradation of SPELA hydrogel depended strongly on the number of lactide monomers per macromonomer (nL) and showed a biphasic behavior. For example, as nL increased from 0 to 3.4, 6.4, 11.6, and 14.8, mass loss increased from 7 to 37, 80, 100% and then deceased to 87%, respectively, after 6 weeks of incubation. The addition of 3.4 lactides per macromonomer (<10 wt % dry macromonomer or <2 wt % swollen hydrogel) increased mass loss to 50% after 6 weeks. Molecular dynamic simulations demonstrated that the biphasic degradation behavior was related to aggregation and micelle formation of lactide monomers in the macromonomer in aqueous solution. MSCs encapsulated in SPELA hydrogel expressed osteogenic markers Dlx5, Runx2, osteopontin, and osteocalcin and formed a mineralized matrix. The expression of osteogenic markers and extent of mineralization was significantly higher when MSCs were encapsulated in SPELA hydrogel with the addition of bone morphogenetic protein-2 (BMP2). Results demonstrate that hydrolytically degradable PEG-based hydrogels are potentially useful as a delivery matrix for stem cells in regenerative medicine. PMID:22642902

Moeinzadeh, Seyedsina; Barati, Danial; He, Xuezhong; Jabbari, Esmaiel

2012-06-11

264

Polyethylene Wear in Retrieved Reverse Total Shoulder Components  

PubMed Central

Background Reverse total shoulder arthroplasty has been used to treat rotator cuff tear arthropathy, proximal humeral fractures and for failed conventional total shoulder prostheses. It has been suggested that polyethylene wear is potentially higher in reverse shoulder replacements than in conventional shoulder replacements. The modes and degree of polyethylene wear have not been completely elucidated. The purpose of this study was to evaluate polyethylene wear patterns in seven specimens retrieved at revision arthroplasty and identify factors that may be associated with increased wear. Methods Reverse total shoulder components were retrieved from 7 patients during revision arthroplasty for loosening and/or pain. Pre-operative glenoid tilt and placement, and scapular notching were evaluated using pre-operative radiographs. Polyethylene wear was evaluated using microCT and optical microscopy. Results Wear on the rim of the polyethylene humeral cup, was identified on all retrieved components. The extent of rim wear varied from a penetration depth of 0.1 to 4.7 mm. We could not demonstrate a correlation between scapular notching and rim wear. However, rim wear was more extensive when the inferior screw had made contact with the liner. Metal on metal wear between the humeral component and the inferior screw of one component was also observed. Wear of the intended bearing surface was minimal. Discussion Rim damage was the predominant cause of polyethylene wear in our retrieved specimens. Direct contact between the humeral component and inferior metaglene screws is concerning because this could lead to accelerated UHMWPE wear and also induce mechanical loosening of the glenoid component.

Day, Judd S; MacDonald, Daniel W; Olsen, Madeline; Getz, Charles; Williams, Gerald R; Kurtz, Steven M

2011-01-01

265

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

266

On the dielectric response of silica-based polyethylene nanocomposites  

NASA Astrophysics Data System (ADS)

The dielectric response of silica-based polyethylene nanocomposites is studied by dielectric spectroscopy. The results indicate that nanocomposites absorb significantly more water than unfilled polyethylene, with the consequence that both permittivity and loss tangent increase with increasing duration of water immersion. However, appropriate surface treatment of nanosilica is found to reduce the water absorption effect and to modify the dielectric response of the nanocomposites compared with those containing untreated nanosilica. While water absorption may not be a technologically desirable characteristic, our results indicate that water molecules can act as effective dielectric probes of interfacial factors.

Y Lau, K.; Vaughan, A. S.; Chen, G.; Hosier, I. L.; Holt, A. F.

2013-03-01

267

SiO2 - polyethylene reflected critical assembly  

SciTech Connect

The Planet universal critical assembly machine was used to perform a series of three critical experiments. This experiment used HEU foils reflected by polyethylene and interleaved with plates of SiO{sub 2} glass and polyethylene. Only the experiment performed using the SiO{sub 2} matrix material is evaluated in this report. The assembly was delayed critical with 33 HEU foils or 17 units (sets of HEU foils). The critical assembly has an intermediate neutron spectrum, with 51.2% of the fissions occurring between 0.625 eV and 100 keV. The calculational results show good agreement with the experimental results.

Brewer, R. W. (Roger W.); Sanchez, R. G. (Rene G.)

2001-01-01

268

Unexpected Shish-Kebab Structure in a Sheared Polyethylene Melt  

NASA Astrophysics Data System (ADS)

Scanning electron micrographs of a solvent-extracted sheared polyethylene (PE) blend revealed, for the first time, an unexpected shish-kebab structure with multiple shish. The blend contained 2 wt % of crystallizing ultrahigh molecular weight polyethylene (UHMWPE) and 98 wt % of noncrystallizing PE matrix. The formation of multiple shish was attributed to the coil-stretch transition occurring in sections of UHMWPE chains. Synchrotron x-ray data provided clear evidence of the hypothesis that multiple shish originate from stretched chain sections and kebabs originate from coiled chain sections, following a diffusion-controlled crystallization process.

Hsiao, Benjamin S.; Yang, Ling; Somani, Rajesh H.; Avila-Orta, Carlos A.; Zhu, Lei

2005-03-01

269

Unexpected shish-kebab structure in a sheared polyethylene melt.  

PubMed

Scanning electron micrographs of a solvent-extracted sheared polyethylene (PE) blend revealed, for the first time, an unexpected shish-kebab structure with multiple shish. The blend contained 2 wt % of crystallizing ultrahigh molecular weight polyethylene (UHMWPE) and 98 wt % of noncrystallizing PE matrix. The formation of multiple shish was attributed to the coil-stretch transition occurring in sections of UHMWPE chains. Synchrotron x-ray data provided clear evidence of the hypothesis that multiple shish originate from stretched chain sections and kebabs originate from coiled chain sections, following a diffusion-controlled crystallization process. PMID:15903890

Hsiao, Benjamin S; Yang, Ling; Somani, Rajesh H; Avila-Orta, Carlos A; Zhu, Lei

2005-03-22

270

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

Federal Register 2010, 2011, 2012, 2013

...entitled ``Polyethylene Retail Carrier Bags from Thailand--Landblue (Thailand...and ``Polyethylene Retail Carrier Bags from Thailand--Amended Final Results...selected respondents, Landblue and Thai Plastic Bags Industries Co.,...

2011-11-03

271

Reference Standard Polyethylene Resins and Piping Materials. Annual Report October 1, 1984-September 30, 1985.  

National Technical Information Service (NTIS)

Polyethylene piping is currently in widespread use in gas distribution in the United States, and represents approximately 80% of new installation. Research that is currently being performed on gas pipes often employs many different polyethylenes selected ...

C. M. Guttman F. W. Wang H. L. Wagner J. M. Crissman J. R. Maurey

1985-01-01

272

40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.  

Code of Federal Regulations, 2010 CFR

...SUBSTANCES Significant New Uses for Specific Chemical...polyethylene glycol phosphate, potassium salt. (a) Chemical...and significant new uses subject to reporting...polyethylene glycol phosphate, potassium salt...

2009-07-01

273

40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.  

Code of Federal Regulations, 2010 CFR

...SUBSTANCES Significant New Uses for Specific Chemical...polyethylene glycol phosphate, potassium salt. (a) Chemical...and significant new uses subject to reporting...polyethylene glycol phosphate, potassium salt...

2010-07-01

274

76 FR 26241 - Polyethylene Retail Carrier Bags From Thailand: Extension of Time Limit for Preliminary Results...  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF COMMERCE International Trade Administration...A-549-821] Polyethylene Retail Carrier Bags From Thailand...Import Administration, International Trade Administration...Import Administration, International Trade Administration...order on polyethylene retail carrier bags from...

2011-05-06

275

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

Federal Register 2010, 2011, 2012, 2013

...polyethylene terephthalate film, sheet and strip from...Garware), Jindal Poly Films Limited of India (Jindal...Polyethylene Terephthalate Film, Sheet and Strip From...Petitioners are DuPont Teijin Films, Mitsubishi Polyester Film, Inc., SKC,...

2012-01-25

276

Fourier-Transform Infrared Linear Dichroism: Stretched Polyethylene as a Solvent in IR Spectroscopy,  

National Technical Information Service (NTIS)

The infrared linear dichroism of several dozen symmetrical organic molecules of low polarity has been measured on their solid solutions in stretched polyethylene and stretched perdeuterated polyethylene. Both saturated and unsaturated molecules, ranging i...

J. G. Radziszewski J. Michl

1986-01-01

277

21 CFR 878.5000 - Nonabsorbable poly(ethylene terephthalate) surgical suture.  

Code of Federal Regulations, 2010 CFR

...Nonabsorbable poly(ethylene terephthalate) surgical suture. 878.5000 Section 878...GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.5000 Nonabsorbable poly(ethylene terephthalate) surgical suture. (a)...

2010-04-01

278

21 CFR 878.5000 - Nonabsorbable poly(ethylene terephthalate) surgical suture.  

Code of Federal Regulations, 2013 CFR

...Nonabsorbable poly(ethylene terephthalate) surgical suture. 878.5000 Section 878...GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.5000 Nonabsorbable poly(ethylene terephthalate) surgical suture. (a)...

2013-04-01

279

Calculated minimum critical masses of (sup 239)Pu homogeneously mixed with polyethylene moderator.  

National Technical Information Service (NTIS)

The minimum critical masses of Plutonium 239 in a polyethylene moderator were calculated as a function of plutonium density for several polyethylene densities (various void fractions). This study has applications for solid transuranic (TRU) waste and for ...

L. M. Gundy A. Q. Goslen

1997-01-01

280

75 FR 25207 - Polyethylene Retail Carrier Bags From Malaysia: Extension of Time Limit for Preliminary Results...  

Federal Register 2010, 2011, 2012, 2013

...Polyethylene Retail Carrier Bags From Malaysia: Extension of Time Limit for Preliminary...polyethylene retail carrier bags from Malaysia for the period August 1, 2008, through...of the sole respondent, Europlastics Malaysia Sdn. Bhd. Therefore, in...

2010-05-07

281

Transport and structural characteristics of crosslinked poly(ethylene oxide) rubbers  

Microsoft Academic Search

Three series of crosslinked poly(ethylene oxide) rubbers have been prepared by photopolymerization of prepolymer solutions containing: (1) poly(ethylene glycol) diacrylate (PEGDA) and H2O, (2) PEGDA and poly(ethylene glycol) methyl ether acrylate (PEGMEA), and (3) PEGDA and poly(ethylene glycol) acrylate (PEGA). All of these polymers have similar chemical composition (approximately 82wt.% ethylene oxide), but the crosslink density and the content and

Haiqing Lin; Elizabeth Van Wagner; John S. Swinnea; Benny D. Freeman; Steven J. Pas; Anita J. Hill; Sumod Kalakkunnath; Douglass S. Kalika

2006-01-01

282

Tertiary polymer recycling: study of polyethylene thermolysis as a first step to synthetic diesel fuel  

Microsoft Academic Search

High density polyethylene (HDPE) thermolysis and polyethylene derived oil hydrogenation were studied as two steps of a novel process to convert waste polyethylene (PE) into a hydrocarbon liquid suitable for use as diesel fuel. This report is focused on the thermolysis of PE. The effects of reaction conditions on reaction rate as well as on the physical and chemical properties

Norbert Horvat; Flora T. T. Ng

1999-01-01

283

The synthesis of modified polyethylene via coordination polymerization followed by ATRP, RAFT, NMRP or ROP  

Microsoft Academic Search

Research on the synthesis of modified polyethylene (PE) is of great significance to both academic study and industrial applications. The synthesis of modified polyethylene has experienced remarkable and significant progress in the control over the microstructure, composition, molecular weight and molecular weight distribution of the polymeric products. This review summarizes the achievements in the synthesis of modified polyethylene via combining

Yulai Zhao; Li Wang; Anguo Xiao; Haojie Yu

2010-01-01

284

Lithium ion transport in a model of amorphous polyethylene oxide  

Microsoft Academic Search

Summary We have made a molecular dynamics study of transport of a single lithium ion in a previously reported model of amorphous polyethylene oxide. New ab initio calculations of the interaction of the lithium ion with 1,2-dimethoxyethane and with dimethyl ether are reported which are used to determine force fields for the simulation. We report preliminary calculations of solvation energies

P. T. Boinske; L. Curtiss; J. W. Halley; B. Lin; A. Sutjianto

1996-01-01

285

Medium density polyethylene composites with functionalized carbon nanotubes  

Microsoft Academic Search

A strong interface between the single-walled carbon nanotubes (SWNTs) and polymer matrix is necessary to achieve enhanced mechanical properties of composites. In this work a series of sidewall-functionalized SWNTs have been investigated in order to evaluate the effect of functionalization on SWNT aspect ratio and composite interfacial chemistry and their role on mechanical properties of a medium density polyethylene (MDPE)

Merlyn X. Pulikkathara; Oleksandr V. Kuznetsov; Ivana R. G. Peralta; Xin Wei; Valery N. Khabashesku

2009-01-01

286

Severe polyethylene wear in uncemented acetabular cup system components  

Microsoft Academic Search

We report 5 cases of severe failure of the polyethylene liner at 4 to 7.4 years after uncemented anatomic medullary locking (AML) total hip arthroplasty, using the acetabular cup system (ACS). The mode of failure was by a combination of wear through to the metal backing and liner fracture. Four of the 5 cases were associated with a 32-mm head.

Jig Patel; James E. Scott; Warwick J. P. Radford

1999-01-01

287

Thermal Conductivity of Single-Walled Carbon Nanotube \\/ Polyethylene Nanocomposites  

Microsoft Academic Search

The thermal conductivity of nanocomposites with single walled carbon nanotubes (SWNTs) and polyethylene are being investigated with attention to the effect of the degree of PE crystallinity and the alignment of both the PE and SWNT. The nanocomposites were prepared via the hot-coagulation method, resulting in a good dispersion of the SWNTs in the polymer matrix. Characterization methods include the

Reto Haggenmueller; Jesse J. Cugliotta

2005-01-01

288

Control of Osmotic Pressure of Culture Solutions with Polyethylene Glycol  

Microsoft Academic Search

Experiments with kidney beans indicate that Carbowax polyethylene glycol, molecular weight 20,000, upon purification, may be used as an agent to control the osmotic pressure of plant nutrient solutions without the hazard of interference with normal metabolic processes. With the sodium electrode and the thermocouple psychrometer, interaction between ions and Carbowax is shown to lead to a slight dissociation of

J. V. Lagerwerff; Gen Ogata; Harold E. Eagle

1961-01-01

289

Thermal conductivity of boron nitride reinforced polyethylene composites  

Microsoft Academic Search

The thermal conductivity of boron nitride (BN) particulates reinforced high density polyethylene (HDPE) composites was investigated under a special dispersion state of BN particles in HDPE, i.e., BN particles surrounding HDPE particles. The effects of BN content, particle size of HDPE and temperature on the thermal conductivity of the composites were discussed. The results indicate that the special dispersion of

Wenying Zhou; Shuhua Qi; Qunli An; Hongzhen Zhao; Nailiang Liu

2007-01-01

290

Obtaining of bactericidal polyethylene terephthalate films modified by silver nanoparticles  

Microsoft Academic Search

The synthesis of stable, concentrated (to 3 g\\/l), and highly dispersive silver aquasols stabilized by cetyltrimethylammonium\\u000a bromide was proposed. The possibility of silver-nanoparticle modification of polyethylene terephthalate preliminarily deformed\\u000a by the crazing mechanism was discussed. Microbiological tests using Pseudomonas aeruginosa bacteria showed that produced nanocomposites feature a pronounced biocide effect.

Yu. A. Krutyakov; E. G. Rukhlya; A. V. Artemov; A. Yu. Olenin; M. N. Ivanov; O. V. Shelyakov

2008-01-01

291

Ultrahigh strength polyethylene by hot drawing of surface growth fibers  

Microsoft Academic Search

Hot drawing at 150°C has been applied to high molecular weight polyethylene fibers produced by flow induced crystallization in a Couette apparatus, referred to as the ‘surface growth’ technique. A distinct improvement of the tensile properties of the fibers was noticed upon drawing. A tensile strength at break of 4.7 GPa was reached. Drawability is discussed in relation to fiber

J. Smook; J. C. Torfs; P. F. van Hutten; A. J. Pennings

1980-01-01

292

Orthorhombic phase of crystalline polyethylene: A Monte Carlo study  

Microsoft Academic Search

In this paper we present a classical Monte Carlo simulation of the orthorhombic phase of crystalline polyethylene, using an explicit atom force field with unconstrained bond lengths and angles and periodic boundary conditions. We used a recently developed algorithm which apart from standard Metropolis local moves employs also global moves consisting of displacements of the center of mass of the

R. Martonák; W. Paul; K. Binder

1997-01-01

293

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

294

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

295

Crosslinking reactions in an unsaturated low density polyethylene  

Microsoft Academic Search

The peroxide crosslinking properties of a new group of low density polyethylenes (LDPE), unsaturated LDPE, were investigated. These are copolymers between ethylene and 1,9-decadiene and contain a higher number of vinyl groups than ‘ordinary’ LDPE, situated on pendant carbon chains. Copolymers with different amounts of vinyl groups were crosslinked with dicumylperoxide at 180°C and the crosslinking reaction was followed by

B. Gustafsson

1997-01-01

296

Elongational behaviour of a low density polyethylene melt  

Microsoft Academic Search

Summary In addition to earlier findings ofMeißner on a low density polyethylene that in the linear range of deformation the time-dependent elongational viscosity is three times the shear viscosity the validity of the relationship\\u000a

H. Münstedt; H. M. Laun

1979-01-01

297

Space charge formation in ?-irradiated low density polyethylene  

Microsoft Academic Search

Energetic ionizing radiation can alter the chemical structure of polymeric materials and also may give rise to the presence of trapped charge within the material, the trapping characteristics of which may be influenced by these radiation-induced structural alterations. In the present work, the formation of space charge in ?-irradiated LDPE (low-density polyethylene) was investigated using the technique of a LIPP

G. Chen; H. M. Banford; A. E. Davies

1998-01-01

298

Procurement of Primary Reference Materials: Low Density Polyethylene.  

National Technical Information Service (NTIS)

The objective of this contract is to prepare, characterize and supply quantities of stable, reproducible, and chemically pure low-density polyethylene (LDPE) in the form of tubes and sheets. This material is to be used by NIH-designated investigators as a...

B. Ashar E. Wong D. Lederman B. Benton

1980-01-01

299

Dielectric Spectrscopy Analysis Behavior of low Density Polyethylene  

Microsoft Academic Search

Dielectric spectroscopy is a powerful tool in the investigation of dipolar and conduction in electrical insulating materials. In particular, the localisation of space charges at crystalline - amorphous interfaces in a semicrystalline polymer, such as low density polyethylene LDPE, provides on internal field which could be unfavourable to the insulating properties of the polymer. A physical displacement of space charges

A. Medjdoub; A. Boubakeur; T. Lebey

2008-01-01

300

Mechanical Performance Improvement of Low-Density Polyethylene Blends  

Microsoft Academic Search

Mechanical properties of recycled low-density polyethylene have been improved by using calcium carbonate as a filler. Compatibility of the filler with a matrix is not sufficient to lead to materials with good elongation at break. This compatibility has been increased by introducing 5 or 10% of compatibilizers as triblock copolymers of styrene and butadiene modified with maleic anhydride. Good results

Y. Pietrasanta; J. J. Robin; N. Torres; B. Boutevin

1998-01-01

301

Procurement of Primary Reference Materials: Low Density Polyethylene.  

National Technical Information Service (NTIS)

The objective of this contract is to prepare, characterize and supply quantities of stable, reproducible, and chemically pure low-density polyethylene (LDPE) in the form of tubes and sheets. This material is to be used by NIH-designated investigators as a...

E. Wong B. Benton E. Kupski

1981-01-01

302

Certification of Standard Reference Material 1474a, A Polyethylene Resin.  

National Technical Information Service (NTIS)

The melt flow rate of Standard Reference Material (SRM) 1474a, a linear polyethylene (narrow MWD ethylene-hexene copolymer) resin, was determined to be 5.10 g/10 min at 190 degrees C under a load of 2.16 kg using the ASTM Method D 1238-00. The average res...

J. R. Maurey K. M. Flynn C. M. Guttman

2003-01-01

303

Electroluminescence of ultraviolet and thermally aged low density polyethylene  

Microsoft Academic Search

It has been postulated that long term ageing of low-density polyethylene (LDPE) is due to the movement of space charge within the dielectric. Electroluminescence (EL) has been shown as an alternative method to investigate charge movement within a dielectric. Under ac fields, EL is related to the injection, trapping and recombination of charge carriers at the sample interface. This work

D. H. Mills; P. L. Lewin; G. Chen; A. M. Ariffin

2010-01-01

304

Positronium formation in low-density polyethylene (LDPE)  

Microsoft Academic Search

Positron annihilation lifetime spectroscopy has been applied to low-density polyethylene (LDPE) as a function of the temperature and also the elapsed time in the dark as well as in the light. Positronium formation below, around and above the glass transition temperature of LDPE was investigated. It was found that far below the glass transition temperature, Tg, the o-Ps intensity increased

Chunqing He; Takenori Suzuki; V. P. Shantarovich; Lin Ma; Masaru Matsuo; Kenjiro Kondo; Yasuo Ito

2003-01-01

305

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

306

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

307

Dynamic tensile testing of aramid and polyethylene fiber composites  

Microsoft Academic Search

Dynamic properties of materials such as aramid and polyethylene fiber reinforced composites are rarely found in the literature, in spite of their significance in ballistic design. It is also difficult to find detailed descriptions of the testing techniques and procedures to characterize these materials. This paper describes a dynamic tensile testing technique for these composite materials, and discusses problems such

I. S. Chocron Benloulo; J. Rodríguez; M. A. Martínez; V. Sánchez Gálvez

1997-01-01

308

Differences in Taste between Two Polyethylene Glycol Preparations  

Microsoft Academic Search

Background and aims. Polyethylene glycol preparations (PEG) are increasingly used for chronic constipation in both adults and children. There are some suggestions that PEG 4000 with orange flavour (Forlax®) tastes better than PEG 3350 which contains salt (Movicolon®). Poor taste is an important factor for non-compliance and is one of the leading causes of therapy failure. The aim of the

Maria M. Szojda; Chris J. J. Mulder; Richelle J. F. Felt-Bersma

309

Polyethylene-Based Polyurethane Copolymers and Block Copolymers.  

National Technical Information Service (NTIS)

Low molecular weight hydroxy terminated polyethylene (HTPE) containing on average an ethyl group every 16-18 carbon atoms, and a hydroxy functionality of 2.6, has been used to prepare polyurethane copolymers and block copolymers which have good solvent re...

C. A. Byme C. R. Desper N. S. Schneider B. Chu Y. J. Li

1994-01-01

310

Polymeric Cracking of Waste Polyethylene Terephthalate to Chemicals and Energy  

Microsoft Academic Search

Polyethylene terephthalate (PET) is a widely used thermo-plastic. PET residues represent on average 7.6 wt% of the different polymer wastes in Europe. Pyrolysis of these wastes is attracting increasing interest, and PET is a potential candidate for this thermal process. The paper measures and discusses the kinetics of the pyrolysis reaction in terms of the reaction rate constants as determined

Anke Brems; Jan Baeyens; Carlo Vandecasteele; Raf Dewil

2011-01-01

311

Determination of phosphate in water after storage in polyethylene  

Microsoft Academic Search

The changes in phosphate concentration which take place when lake water is stored in polyethyleno bottles have been studied. The reduction in phosphate concentration which occurs is attributed to bacterial action and not to absorption of phosphate by the polyethy- lene. Appreciable changes in phosphate concentration can be avoided by collecting the sample in a polyethylene bottle which has been

J. HERON

1962-01-01

312

Explicit Treatment of Hydrogen Atoms in Thermal Simulations of Polyethylene  

Microsoft Academic Search

Most atomistic simulation studies of polyethylene employ a united-atom representation to reduce complexity and computational costs. The ramifications of such an approximation have been discussed with respect to structural properties but have not been examined with respect to thermal properties. Here we investigate the consequences of simplified united-atom representations by comparing results from the Kirkwood model to molecular dynamics simulations

Asegun Henry; Gang Chen

2009-01-01

313

Heat fusion of different brands of polyethylene piping  

Microsoft Academic Search

Plexco tested specific fusion procedures for joining Plexco-manufactured plastic piping and fittings to those made by other suppliers from different brands of polyethylene. The evaluations compared to properties of PE 2306, 3406, and 3408 and the relative strengths of various types of joints. The laboratory and field data verified that trained operators using proper fusion techniques can effectively join different

Petro

1981-01-01

314

Thermal expansion of polymers: Mechanisms in orthorhombic polyethylene  

Microsoft Academic Search

Quasiharmonic lattice dynamics is used to examine the mechanisms underlying the anisotropic thermal expansion of orthorhombic polyethylene, with particular attention to low temperature behavior. Several sets of interatomic potentials all give good qualitative agreement with experiment. Tensions caused by vibrations with components away from the bond directions are responsible for the negative expansion along the polymer chains, and contribute significantly

J. A. O. Bruno; N. L. Allan; T. H. K. Barron; A. D. Turner

1998-01-01

315

Fibrous Structure Formation in Cold-Drawing of Polyethylene.  

National Technical Information Service (NTIS)

Rods of spherulitic, linear polyethylene were cold-drawn at 60 and 100C and the morphology of the drawn material, particularly the necked portion, was characterized by light and electron microscopy and by wide- and small-angle x-ray scattering. The drawin...

D. Hansen J. D. Muzzy

1970-01-01

316

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 ...

317

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...

318

The Effect of Downgauging on the Physicomechanical Properties of Film Blends of Linear Low-density Polyethylene with Low-density Polyethylene  

Microsoft Academic Search

Two series of film formulations are investigated comprising blends of a metallocene-catalyzed linear low-density polyethylene (mLLDPE) or a conventional linear low-density polyethylene (LLDPE) with a low-density polyethylene (LDPE). The physicomechanical and optical properties are studied at various gauge lengths to investigate the effects of downgauging the films, particularly those containing mLLDPE. The potential for downgauging is found to be optimum

Marlene J. Cran; Stephen W. Bigger

2005-01-01

319

The effect of varying the polyethylene content and the co-polymer content on crazing in polystyrene—low-density polyethylene blends  

Microsoft Academic Search

The effect of varying the low-density polyethylene content and the polystyrenepolyethylene block co-polymer content on the rates of craze initiation and craze growth in polystyrene\\/low-density polyethylene blends has been studied. it was found that the parameters in the Eyring rate coefficients for craze initiation and craze growth are not dependent on the low-density polyethylene content. However, the rates of craze

S. D. Sjoerdsma; M. E. J. Dekkers; D. Heikens

1982-01-01

320

Nanoscale morphologies of polystyrene and polyethylene ionomers  

NASA Astrophysics Data System (ADS)

Ionomers are highly valued for their unique properties and therefore have long been studied to characterize, understand, and improve these properties. Many studies have focused on the bulk properties of ionomers with more recent efforts using X-ray scattering to characterize the nanometer scale structure especially the ionic aggregate. Scanning transmission electron microscopy (STEM) technology has developed to the point within the past decade that direct imaging of the ionic aggregate is possible. In this dissertation, STEM techniques are refined by accounting for extensive overlap in the projected image and STEM techniques along with X-ray scattering methods are used to study a unique group of poly(ethylene-co-acrylic acid) (P(E-AA)) copolymers and ionomers. We examined poly(styrene-ran-7%-methacrylic acid) Cu (P(S-MAA0.07) Cu) ionomer with model dependant X-ray scattering and direct imaging through STEM. Using the liquid-like hard sphere X-ray scattering model proposed by Yarusso and Cooper with Fornet interference, the ionic aggregate number density indicate an extensively overlapped system for the STEM imaging. Thus, to properly interpret the STEM data, the extensive overlap must be corrected. By creating a computer model that is able to simulate STEM images from an X-ray model, the amount of overlap can be estimated and a proper number density can be calculated from the STEM images. The number density calculated from STEM agrees with the X-ray scattering. Also, despite the extensive overlap, the brightest, isolated features in the STEM are of the appropriate size and shape that would be expected from the projection of a single ionic aggregate. Therefore, the STEM and X-ray scattering are in agreement about the morphology of the ionic aggregates in these P(S-MAA0.07) Cu ionomers. These experiments are repeated for poly(styrene-ran-1.9%-sulfonated styrene) neutralized by Cu, Zn, Ba, or Cs and found that the liquid-like hard sphere X-ray model and the STEM agree on the size, shape, distribution, and number density of the ionic aggregates. We generalize our simulation method to projection of overlapping spheres. A procedure is developed to create and analyze large numbers of simulated projections through computer algorithms. To analyze the data set, it is plotted on axes chosen to reduce the number of variables that influenced the number of features counted in the simulated image (N2D) as a function of simulation thickness (t). The dependant axis is N2D normalized by the area of the simulation in units of 4 times the square of the sphere radius. The independent axis is simply the thickness in units of the sphere radius. With these axes, the important variable is the volume fraction of spheres (? R). In addition, there is a critical thickness, t c, where if t < tc, then the normalized N2D is proportional to talpha and if t > t c, the normalized N2D is independent of thickness at a value of beta. By knowing the thickness of the sample, the normalized N2D, the volume fraction can be estimated and thus the number of spheres in the volume can be calculated. Finally, we study the morphology of linear P(E-AA) copolymers with precisely-sequenced and irregularly sequenced acid groups to establish the effect that the acid group sequence has on the crystal structure. The linear irregularly-sequenced P(E-AA) copolymers behave similarly to low density poly(ethylene-acrylic acid) forming an orthorhombic polyethylene crystal structure and excluding the acid groups to the amorphous regions. The linear precisely-sequenced P(E-AA) copolymers exhibit an unique structure with the acids forming large planar layers that are incorporated into the crystal structure. The precisely-sequence linear P(E-AA) ionomers exhibit both the new acid layer structures and the traditional ionic aggregates. With increasing neutralization, the crystallinity of the P(E-AA) and the new acid layer structure decrease as the acid groups necessary are co-opted to form the ionic aggregates in the amorphous regions.

Chan, Christopher D.

321

Preparation and Characterization of Potato Starch Based Low Density Polyethylene\\/Low Density Polyethylene Grafted Maleic Anhydride Biodegradable Polymer Composite  

Microsoft Academic Search

Polysaccharide-filled plastics have attracted immense interest from research scientists as a means to develop a biodisintegrable polymer. The objective of the present study is to develop a biodisintegrable polymer composite using potato starch, which may be a step toward an alternative user friendly polymer composite. Keeping in mind the compatibility issue between potato starch and polyethylene, we used a base

A. P. Gupta; Manjari Sharma; Vijai Kumar

2008-01-01

322

Pressure effects on viscosity and flow stability of polyethylene melts during extrusion  

Microsoft Academic Search

In the present work, the effects of pressure on the viscosity and flow stability of four commercial grade polyethylenes (PEs)\\u000a have been studied: linear-low-density polyethylene copolymer, high-density polyethylene, metallocene polyethylenes with short-chain\\u000a branches (mPE-SCB), and metallocene polyethylenes with long chain branching (mPE-LCB). The range of shear rates considered\\u000a covers both stable and unstable flow regimes. “Enhanced exit-pressure” experiments have been

Enric Santanach Carreras; Nadia El Kissi; Jean-Michel Piau; Fabrice Toussaint; Sophie Nigen

2006-01-01

323

Heteromerous interactions among glycolytic enzymes and of glycolytic enzymes with F-actin: effects of poly(ethylene glycol).  

PubMed

Interactions of glucose-6-phosphate isomerase (D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9), aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate lyase, EC 4.1.2.13), glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12), triose-phosphate isomerase (D-glyceraldehyde-3-phosphate ketol-isomerase, EC 5.3.1.1), phosphoglycerate mutase (D-phosphoglycerate 2,3-phosphomutase, EC 5.4.2.1), phosphoglycerate kinase (ATP:3-phospho-D-glycerate 1-phosphotransferase, EC 2.7.3), enolase (2-phospho-D-glycerate hydro-lyase, EC 4.2.1.11), pyruvate kinase (ATP:Pyruvate O2-phosphotransferase, EC 2.7.1.40) and lactate dehydrogenase [S)-lactate:NAD+ oxidoreductase, EC 1.1.1.27) with F-actin, among the glycolytic enzymes listed above, and with phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) were studied in the presence of poly(ethylene glycol). Both purified rabbit muscle enzymes and rabbit muscle myogen, a high-speed supernatant fraction containing the glycolytic enzymes, were used to study enzyme-F-actin interactions. Following ultracentrifugation, F-actin and poly(ethylene glycol) tended to increase and KCl to decrease the pelleting of enzymes. In general, the greater part of the pelleting occurred in the presence of both F-actin and poly(ethylene glycol) and the absence of KCl. Enzymes that pelleted more in myogen preparations than as individual purified enzymes in the presence of poly(ethylene glycol) and the absence of F-actin were tested for specific enzyme-enzyme associations, several of which were observed. Such interactions support the view that the internal cell structure is composed of proteins that interact with one another to form the microtrabecular lattice. PMID:3334856

Walsh, J L; Knull, H R

1988-01-01

324

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

2012-12-11

325

Gamma Inert Sterilization: A Solution to Polyethylene Oxidation?  

PubMed Central

Background: In the 1990s, oxidation was found to occur in ultra-high molecular weight polyethylene total joint replacement components following gamma irradiation and prolonged shelf aging in air. Orthopaedic manufacturers developed barrier packaging to reduce oxidation during and after radiation sterilization. The present study explores the hypothesis that polyethylene components sterilized in a low-oxygen environment undergo similar in vivo oxidative mechanisms as inserts sterilized in air. In addition, the potential influence of the different sterilization processes on the wear performance of the polyethylene components was examined. Methods: An analysis of oxidation, wear, and surface damage was performed for forty-eight acetabular liners and 123 tibial inserts. The mean implantation time was 12.3 ± 3.7 years for thirty-one acetabular liners that had been gamma sterilized in air and 4.0 ± 2.5 years for the seventeen acetabular liners that had been gamma sterilized in inert gas. The mean implantation time was 11.0 ± 3.2 years for the twenty-six tibial inserts that had been sterilized in air and 2.8 ± 2.2 years for the ninety-seven tibial inserts that had been gamma sterilized in inert gas. Oxidation and hydroperoxide levels were characterized in loaded and unloaded regions of the inserts. Results: Measurable oxidation and oxidation potential were observed in all cohorts. The oxidation and hydroperoxide levels were regional. Surfaces with access to body fluids were more heavily oxidized than protected bearing surfaces were. This variation appeared to be greater in historical (gamma-in-air-sterilized) components. Regarding wear performance, historical and conventional acetabular liners showed similar wear penetration rates, whereas a low incidence of delamination was confirmed for the conventional tibial inserts in the first decade of implantation. Conclusions: The present study explores the impact of industry-wide changes in sterilization practices for polyethylene. We found lower oxidation and oxidation potential in the conventional acetabular liners and tibial inserts that had been gamma sterilized in inert gas as compared with the historical components that had been gamma sterilized in air. However, we also found strong evidence that conventional components undergo mechanisms of in vivo oxidation similar to those observed following gamma irradiation in air. In addition, gamma sterilization in inert gas did not provide polyethylene with a significant improvement in terms of wear resistance as compared with gamma sterilization in air, except for a lower incidence of delamination in the first decade of implantation for tibial inserts. Clinical Relevance: Our research demonstrates that gamma inert sterilization may have improved, but not completely solved, the problem of polyethylene oxidation for hip and knee arthroplasty.

Medel, Francisco J.; Kurtz, Steven M.; Hozack, William J.; Parvizi, Javad; Purtill, James J.; Sharkey, Peter F.; MacDonald, Daniel; Kraay, Matthew J.; Goldberg, Victor; Rimnac, Clare M.

2009-01-01

326

[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

327

Synergistic effect of polyethylene glycol with arginine on the prevention of heat-induced aggregation of lysozyme  

NASA Astrophysics Data System (ADS)

. Arginine (Arg) is a commonly used additive to prevent protein aggregation and inactivation in denaturing solutions. This paper presents new findings on the synergistic effect on the prevention of heat-induced aggregation of lysozyme using Arg in combination with polyethylene glycol (PEG). The synergistic enhancement was observed in the presence of Arg with amphiphilic polymers, such as PEG6000, PEG20000, and poly(vinyl pyrrolidone), while it was not observed with hydrophilic polymers, such as PEG200, Poly(acrylic acid), poly(vinyl alcohol), dextran, and Ficoll 70.

Tomita, S.; Hamada, H.; Nagasaki, Y.; Shiraki, K.

2008-03-01

328

Polyethylene oxide gel. A new intranasal dressing after septorhinoplasty.  

PubMed

The purpose of intranasal dressings after septorhinoplasty is to absorb secretions, stop bleeding, act as an internal splint, discourage adhesions, and facilitate nasal hygiene. The ideal dressing should conform to the irregularities of the nasal cavity and resist adherence to the wounds of the nasal lining so it can be easily removed. It should be nonirritating, antiseptic, and economical. The failure of previously reported dressings in one or more of these requirements led us to evaluate a new alternative. Polyethylene oxide gel (Vigilon) was identified as a potential improvement and investigated in 48 patients over 17 months. There were no significant complications. Polyethylene oxide gel appears superior to previously described dressings, primarily because of comfort for the patient at removal. PMID:1845263

Salassa, J R; Pearson, B W

1991-12-01

329

Polyethylene oxide gel: a new dressing after endoscopic sinus surgery.  

PubMed

The purpose of dressings after endoscopic sinus surgery is to absorb secretions, tamponade bleeding, discourage adhesions, and facilitate sinus and nasal hygiene. The ideal dressing should conform to the irregularities of the nasal-sinus cavity and resist adherence to the wounds so it can be easily removed. It should be economical, non-irritating, and antiseptic. The failure of previous dressings to fulfill all of these criteria led the author to evaluate a new alternative. Polyethylene oxide gel (Vigilon) was identified as a potential improvement and investigated in a clinical trial of 60 cases. This paper presents the author's observations and technique for application. Polyethylene oxide gel resulted in no significant complications. It appears superior to previously described dressings, primarily because of patient comfort at removal. PMID:1579809

Salassa, J R

1992-03-01

330

Hyperthermal atomic oxygen reactions with kapton and polyethylene  

SciTech Connect

Gas phase reaction products produced by the interaction of high kinetic energy (1--3 eV) {sup 3}P ground state atomic oxygen (AO) with polyethylene and kapton were found to be H{sub 2}, H{sub 2}O, CO, and CO{sub 2} with NO being a possible secondary product from kapton. Hydrogen abstraction at high AO kinetic energy is postulated to be the key reaction controlling the erosion rate of kapton and polyethylene. An Arrhenius-like expression having an activation barrier of 0.4 eV can be fit to the data, which suggests that the rate limiting step in the AO/kapton reaction mechanism can be overcome by translational energy. 16 refs., 13 figs.

Cross, J.B. (Los Alamos National Lab., NM (USA)); Koontz, S.L. (National Aeronautics and Space Administration, Houston, TX (USA). Lyndon B. Johnson Space Center); Gregory, J.C.; Edgell, M.J. (Alabama Univ., Huntsville, AL (USA). Dept. of Chemistry)

1990-01-01

331

Polyethylene encapsulation full-scale technology demonstration. Final report  

SciTech Connect

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 solidification technology for improved, cost-effective treatment of low-level radioactive (LLW), hazardous and mixed wastes. A fully equipped production-scale system, capable of processing 900 kg/hr (2000 lb/hr), has been installed at BNL. The demonstration covered all facets of the integrated processing system including pre-treatment of aqueous wastes, precise feed metering, extrusion processing, on-line quality control monitoring, and process control.

Kalb, P.D.; Lageraaen, P.R.

1994-10-01

332

[Epidemiological studies on the manufacture of cross-linked polyethylene].  

PubMed

In the production of cross-linked polyethylene in the air of the working environment above the norm concentrations of acetophenon, dicumyl peroxide and antioxidant are established, which create unfavourable working conditions. During clinical and laboratory examinations of 55 workers, engaged in the production of cross-linked polyethylene, are registered subjective complaints from the irritating effect of the chemical noxae on the mucous membranes and skin. Methaemoglobinaemia is found in 4 workers. There are deviations in the functional state of the liver (transaminase, APh, GGTP and triglycerides) in the group "maintaining staff". The same workers have also increased quantity of metabolite hippuric acid in the urine. On the grounds of the results, the group "maintaining staff" is determined as risk group. Recommendations are made for follow-up care and work in controlled parameters of the working environment. PMID:2099468

Khankova, L; Mikha?lova, A; Khristeva, V; Mukhtarova, M; Benchev, I; Matakieva, M; Kolarova, S

1990-01-01

333

Spin-coated polyethylene films probed by single molecules.  

PubMed

We have studied ultrathin spin-coated high-density polyethylene films by means of single-molecule spectroscopy and microscopy at 1.8 K. The films have been doped with 2.3,8.9-dibenzanthanthrene (DBATT) molecules, which function as local reporters of their immediate environment. The orientation distributions of single DBATT probe molecules in 100-200 nm thin films of high-density polyethylene differ markedly from those in low-density films. We have found a preferential orientation of dopant molecules along two well-defined, mutually perpendicular directions. These directions are preserved over at least a 2 mm distance. The strong orientation preference of the probe molecules requires the presence of abundant lateral crystal faces and is therefore not consistent with a spherulitic morphology. Instead, a "shish-kebab" crystal structure is invoked to explain our results. PMID:17064117

Wirtz, A C; Hofmann, C; Groenen, E J J

2006-11-01

334

Wettability of grafted poly(ethylene terephthalate) fibers  

Microsoft Academic Search

Graft copolymerisation of perfluorooctyl-2 ethanol acrylic monomer\\/stearyl methacrylate monomer mixture onto poly(ethylene terephthalate) fibers using benzoyl peroxide as initiator was carried out in order to improve water repellency. By characterising the surface free energy, the degree of water repellency can be evaluated. In this article, the Wilhelmy plate method is used to determinate the surface fiber wettability by probe liquids

Ahmida El-Achari; Abdellah Ghenaim; Claude Cazé

2002-01-01

335

Thermal stability of acrylonitrile\\/chlorosulphonated polyethylene rubber blend  

Microsoft Academic Search

The properties of chlorosulphonated polyethylene (CSM) rubber, acrylonitrile rubber (NBR) and their blend (50\\/50 w\\/w) were\\u000a studied. Fourier transform infrared (FTIR) studies supported that CSM\\/NBR rubber blend is self curable, when cross-linking\\u000a takes place between acrylonitrile groups of NBR and –SO2Cl groups or in situ generated allyl chloride moieties of CSM. The thermal stability of vulcanizates was analyzed in nitrogen\\u000a by

Gordana Markovi?; Milena Marinovi?-Cincovi?; Vesna Vodnik; Blaga Radovanovi?; Jaroslava Budinski-Simendi?; Olivera Veljkovi?

2009-01-01

336

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

337

Wear characteristics of ultrahigh molecular weight polyethylene (UHMWPE)  

Microsoft Academic Search

The wear of ultrahigh molecular weight polyethylene (UHMWPE) bearing against 316 stainless steel or cobalt chromium (Co-Cr)\\u000a alloy was measured using a 12-channel wear tester especially developed for the evaluation of candidate materials for prosthetic\\u000a joints. The coefficient of friction and wear rate were determined as a function of lubricant, contact stress, and metallic\\u000a surface roughness in tests lasting 2–3

A. El-Domiaty; M. El-Fadaly; A. Es. Nassef

2002-01-01

338

Effect of substrates on crystallization of high density polyethylene  

Microsoft Academic Search

The experimental observations about remarkable influence of the substrates on the isothermal crystallization rate of a high\\u000a density polyethylene(HDPE) were presented. Two methods were used to characterize the crystallization rate: the change of turbidity\\u000a of the HDPE specimen and the changes of the complex viscosity and storage modulus measured by a rotational rheometer, which\\u000a gave consistent results showing that the

Yu-run Fan; Yuan Lin; Mian-zhao Ruan

2008-01-01

339

Water vapour transport in polyethylene oxide\\/polymethyl methacrylate blends  

Microsoft Academic Search

Polyethylene oxide\\/polymethylmethacrylate (PEO\\/PMMA) blend films have been obtained by evaporation of CHCl3 solutions. The miscibility of the components has been studied by optical microscopy and by differential scanning calorimetry (DSC). The 10\\/90 blend is miscible while the other compositions are biphasic in the amorphous part of the film, the components being either immiscible or partly miscible. The permeability to water

A Daro; C David

1999-01-01

340

Hepatocyte culture on carbohydrate-modified star polyethylene oxide hydrogels  

Microsoft Academic Search

We describe the synthesis and in vitro biological characterization of a new class of carbohydrate-modified hydrogels based on radiation-cross-linked star polyethylene oxide (PEO). Hydrogels were synthesized from either of two types of PEO star molecules in order to vary the terminal hydroxyl content of the gels while keeping other gel properties such as molecular weight between cross-links and water content

Stephanie T. Lopina; George Wu; Edward W. Merrill; Linda Griffith-Cima

1996-01-01

341

Polyethylene oxide does not necessarily aggregate in water  

Microsoft Academic Search

POLYETHYLENE oxide (PEO) is one of the most extensively studied of all water-soluble synthetic polymers, both for its wide range of applications1-4 and from the fundamental standpoint of understanding the behaviour of polymer solutions. The aggregation behaviour of PEO in water and its consequences have been a matter of concern in many studies5-11 of this system. It is not clear,

K. Devanand; J. C. Selser

1990-01-01

342

Biodegradation of thermally-oxidized, fragmented low-density polyethylenes  

Microsoft Academic Search

Thermally degradable low-density polyethylene samples containing TDPA™ pro-oxidant additives from EPI Inc. were submitted to an investigation aimed at evaluating their ultimate biodegradation (e.g. mineralization) in soil and mature compost incubation media. Respirometric tests aimed at simulating soil burial and composting (mature compost) conditions, were used for testing the potential biodegradability of polyolefins in the environment. An LDPE-TDPA film sample

Emo Chiellini; Andrea Corti; Graham Swift

2003-01-01

343

Transient currents in oxidized low-density polyethylene  

Microsoft Academic Search

The currents measured in oxidized low-density polyethylene after a dc step voltage excitation show maxima in the range of\\u000a minutes to hours for temperatures between 20 °C and 80 °C and for field strengths between 20 and 200 kV\\/cm. The current maxima\\u000a are shifted to shorter times by increasing the field strength or the temperature. The transient currents, which are

P. Fischer; P. Röhl

344

Degradation Characterisation of Agricultural Low-density Polyethylene Films  

Microsoft Academic Search

Low-density polyethylene (LDPE) film is currently the most widespread greenhouse covering material in the countries of the Mediterranean region. The exposure of LDPE film to weathering conditions, especially to solar irradiation in the range of 290–400nm, affects its chemical structure and consequently its mechanical and physical properties. At present (current practice), the final characterisation of degradation of LDPE films is

D Briassoulis; A Aristopoulou; M Bonora; I Verlodt

2004-01-01

345

Dielectric properties of zinc oxide\\/low density polyethylene nanocomposites  

Microsoft Academic Search

ZnO\\/low density polyethylene (LDPE) nanocomposites with either homogeneous or controlled inhomogeneous dispersions of ZnO nanoparticles were prepared. The dielectric constants of the composites with filler concentrations up to 40 vol.% were measured and compared with the dielectric constants of conventional submicron size ZnO filled LDPE composite. The filler particles were coated with silane coupling agents and mixed with LDPE to

J. I. Hong; P. Winberg; L. S. Schadler; R. W. Siegel

2005-01-01

346

Elongational behaviour of a low density polyethylene melt  

Microsoft Academic Search

Summary The steady-state elongational viscosityµs of melts of the low density polyethylene IUPAC A was investigated over six decades of strain rate. At low elongation rates the melt behaves as a linear viscoelastic liquid. TheTrouton relationµ0=3?0 is valid. The tensile compliance is one third of the shear compliance. With increasing strain rate the elongational viscosity goes through a pronounced maximum

H. M. Laun; H. Münstedt

1978-01-01

347

Space charge behavior in low-density polyethylene  

Microsoft Academic Search

The space charge distribution in low-density polyethylene (LDPE) was measured with the pulsed electroacoustic (PEA) method. We used three types of LDPE: LDPE-L and LDPE-H were prepared by the high pressure process, and m-LDPE was polymerized with a metallocene catalyst. Space charge in LDPE strongly depended upon the electrode material. Semiconductive electrodes enhanced carrier injection into LDPE and, as a

T. Mizutani; H. Semi; K. Kaneko

2000-01-01

348

The post-yield behaviour of low-density polyethylenes  

Microsoft Academic Search

The post-yield behaviour of linear low-density and high-pressure polymerized low-density polyethylenes have been compared in tension and compression. Rubber elasticity theory has been used to describe the strain-hardening region of the stress-strain curves in terms of extension of amorphous regions and entanglement associated with crystalline regions. The resulting strain-hardening functions were used to predict the geometry of the neck profiles

P. J. Mills; J. N. Hay; R. N. HAYWARDt

1985-01-01

349

Space charge behaviors in low-density polyethylene  

Microsoft Academic Search

The space charge distributions in LDPE( low-density polyethylene) have been measured by PEA (pulsed Electro-Acoustic) method. Two kinds of LDPE were used; LDPE polymerized under a high pressure process and m-LDPE polymerized with metallocene catalyst. The thickness of a sample was about 100 ?m. The space charge distributions in both LDPE and m-LDPE depended on the materials of electrodes. Positive

T. Mizutani; H. Semi; J. Tomioka; K. Kaneko; T. Mori; M. Ishioka

1999-01-01

350

Shear-induced nonisothermal crystallization of low-density polyethylene  

Microsoft Academic Search

The effect of melt memory on the shear-induced nonisothermal crystallization of a low-density polyethylene melt is analyzed with a shear DTA instrument. The melt state responsible for the saturation of shear-induced isothermal crystallization was identified previously as the steady state in steady shear flows and the strain applied to the melt was identified as the controlling factor for that saturation.

Weidong Zhang; José A. Martins

2007-01-01

351

Poly(ethylene oxide) and its blends with sodium alginate  

Microsoft Academic Search

A series of blends based on poly(ethylene oxide) (PEO) and sodium alginate (NaAlg) were prepared by solution casting method. The blends thus obtained were characterized by using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile strength test, contact angle measurements and atomic force microscopy (AFM). FT-IR studies indicate that there are the hydrogen bonding interactions

Tuncer Çaykara; Serkan Demirci; Mehmet S. Ero?lu; Olgun Güven

2005-01-01

352

Photophysics of poly(ethylene terephthalate): Ultraviolet absorption and emission  

SciTech Connect

Polarized and unpolarized emission spectra for poly(ethylene terephthalate) are presented, and a new phosphorescence peak at 564 nm is reported. The spectroscopically parameterized CNDO/S3 model is used to provide a detailed description of the absorption and monomeric emission. Moreover, preliminary computations on an idealized terephthalate dimer indicate that the 368-nm fluorescence and the newly reported phosphorescence emission may be attributable to an associated ground-state dimer.

LaFemina, J.P. (Pacific Northwest Lab., Richland, WA (USA)); Arjavalingam, G. (IBM Thomas J. Watson Research Center, Yorktown Heights, NY (USA))

1991-01-24

353

Photophysics of poly(ethylene terephthalate): Ultraviolet absorption and emission  

Microsoft Academic Search

Polarized and unpolarized emission spectra for poly(ethylene terephthalate) are presented, and a new phosphorescence peak at 564 nm is reported. The spectroscopically parameterized CNDO\\/S3 model is used to provide a detailed description of the absorption and monomeric emission. Moreover, preliminary computations on an idealized terephthalate dimer indicate that the 368-nm fluorescence and the newly reported phosphorescence emission may be attributable

John P. LaFemina; G. Arjavalingam

1991-01-01

354

EPDM\\/polyamide TPV compatibilized by chlorinated polyethylene  

Microsoft Academic Search

A thermoplastic vulcanizate (TPV) of ethylene-propylene-diene (EPDM) and polyamide (PA) with excellent mechanical properties was prepared by dynamic vulcanization. The effects of the vulcanizing agents, compatibilizer, PA content, aging and reprocessing on mechanical properties of EPDM\\/PA thermoplastic vulcanizate were investigated. Experimental results indicate that chlorinated polyethylene has a better effect in compatibilizing the EPDM\\/copolyamide blends compared with the other compatibilizers,

Xin Liu; Hua Huang; ZhiYun Xie; Yong Zhang; YinXi Zhang; Kang Sun; LiNa Min

2003-01-01

355

The effects of oxidation on the electrical conduction of polyethylene  

Microsoft Academic Search

The effects of oxidation on the electrical conduction of low- and high-density polyethylene (LD-PE and HD-PE) have been studied. It has been found that oxidation enhances the carrier mobility in LD-PE, but lowers that in HD-PE. A qualitative explanation of these opposing effects is given, based on the assumption that carbonyl groups introduced in the amorphous regions of PE act

T. Mizutani; T. Tsukahara; M. Ieda

1980-01-01

356

Low-temperature thermal properties of nylon and polyethylene  

Microsoft Academic Search

The thermal conductivity and heat capacity of polyethylene and nylon samples have been measured in the temperature range 0.15–4°K. A good theoretical fit is obtained for the thermal conductivity above 1°K by using a Debye ?2 phonon frequency distribution with constant mean free path internal boundary scattering and amorphous structure scattering. Below 1°K the experimental results show a lower power

Terry A. Scott; Johannes de Bruin; Monte M. Giles; Colin Terry

1973-01-01

357

Creep recovery behavior of metallocene linear low-density polyethylenes  

Microsoft Academic Search

The rheological behavior of two metallocene linear low-density polyethylenes (mLLDPE) is investigated in shear creep recovery\\u000a measurements using a magnetic bearing torsional creep apparatus of high accuracy. The two mLLDPE used are homogeneous with\\u000a respect to the comonomer distribution. The most interesting feature of the two mLLDPE is that their molecular mass distributions\\u000a are alike. Therefore, as one of the

Claus Gabriel; Helmut Münstedt

1999-01-01

358

Deformation processes in poly(ethylene terephthalate) fibers  

Microsoft Academic Search

The structure\\/property relationships in a series of melt-spun poly(ethylene terephthalate) (PET) fibers processed under different conditions have been investigated. The structure of the fibers was characterized using a variety of techniques, including gel permeation chromatography (GPC), differential scanning calorimetry (DSC), optical birefringence, and wide-angle x-ray scattering (WAXS). The mechanical properties of the PET fibers were also investigated, and the fibers

W.-Y. Yeh; R. J. Young

1998-01-01

359

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

360

Structures and properties of different low density polyethylenes  

Microsoft Academic Search

Low density polyethylenes (LDPE) made by the known high pressure processes show significantly different molecular structures. When the reaction conditions are variable, e.g. in a tubular reactor (resinT) or in a system of two autoclaves with a lower temperature in the first reactor (resinA2*), the polymer shows a narrower molecular weight distribution, but wider distributions of long-chain and short-chain branching

R. Kuhn; H. Krömer

1982-01-01

361

Electric Breakdown of Solution-Grown Polyethylene Films without Spherulite  

Microsoft Academic Search

Self-healing breakdown tests are made at room temperature on solution-grown polyethylene (PE) films without heat treatment. The non heat-treated film has no spherulite and consists of randomly oriented lamellae, in contrast to the heat-treated film consisting of two-dimensional spherulites. The variation of electric strength with voltage rising speed and voltage polarity gives a feature similar to the previous results for

Keiichi Kitagawa; Goro Sawa; Masayuki Ieda

1982-01-01

362

Investigation of the Hydraulic Resistance in Polyethylene Pipelines  

Microsoft Academic Search

The hydraulic resistance to a flow propagating in polyethylene pipelines with a velocity characteristic of flows propagating in gas-supply systems has been experimentally investigated. The experimental data have been processes statistically with the use of the maximum-likehood method and regression analysis. The hydraulic-resistance coefficient has been approximated using the Colebrook-White, Prandtl, and other models. Corrections to the hydraulic formulas used

M. G. Sukharev; A. M. Karasevich; R. V. Samoilov; I. V. Tverskoi

2005-01-01

363

Silicon nanowire and polyethylene superhydrophobic surfaces for discrete magnetic microfluidics  

Microsoft Academic Search

A microfluidic method to manipulate small drops of water is studied on two different superhydrophobic surfaces. Using this digital magnetofluidic method, water drops containing paramagnetic carbonyl-iron microparticles were displaced on silicon nanowire (Si NW) and low-density polyethylene (LDPE) superhydrophobic surfaces using magnetic fields. Horizontal, vertical, or upside-down drop movement is made possible by the action of capillary forces induced by

Ana Egatz-Gómez; John Schneider; P. Aella; Dongqing Yang; P. Domínguez-García; Solitaire Lindsay; S. T. Picraux; Miguel A. Rubio; Sonia Melle; Manuel Marquez; Antonio A. García

2007-01-01

364

Simulated recycling of post-consumer high density polyethylene material  

Microsoft Academic Search

Post-consumer high density polyethylene (HDPE) was examined by a test procedure consisting of repeated cycles of alternating extrusion and subsequent accelerated thermo-oxidative ageing. The material studied was collected from a real waste stream of HDPE bottles. The effect of addition of a commercial re-stabiliser was also studied. The material was evaluated in terms of mechanical and chemical properties, such as

Antal Boldizar; Anna Jansson; Thomas Gevert; Kenneth Möller

2000-01-01

365

Toughness of high-density polyethylene in shear fracture  

Microsoft Academic Search

This paper evaluates the validity of a new test methodology for measuring shear fracture toughness (mode II) of high density\\u000a polyethylene (HDPE). The methodology adopts Iosipescu test for the shear loading, and determines the toughness based on the\\u000a essential work of fracture (EWF) concept. The results show that even under the Iosipescu loading, tensile deformation (mode\\u000a I) is still involved

H. J. Kwon; P.-Y. B. Jar

2007-01-01

366

Fabrication and anti-fouling properties of photochemically and thermally immobilized poly(ethylene oxide) and low molecular weight poly(ethylene glycol) thin films  

Microsoft Academic Search

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

Hui Wang; Jin Ren; Aye Hlaing; Mingdi Yan

2011-01-01

367

Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice  

Microsoft Academic Search

The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic films after dark storage at 20°C. Owing to absorption, the amount of flavour compounds in the model solution

R. W. G. van Willige; J. P. H. Linssen; A. Legger-Huysman; A. G. J. Voragen

2003-01-01

368

On the use of nanoscale indentation with the AFM in the identification of phases in blends of linear low density polyethylene and high density polyethylene  

Microsoft Academic Search

The microstructures generated by blends of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) following isothermal crystallization from the melt have been studied using several techniques. The traditional methods of electron microscopy, wide angle X-ray scattering, and differential scanning calorimetry were used to examine the superstructures, lattice spacings, and thermal properties, respectively. In addition, nanoindentation of specific moieties

M. S. Bischel; M. R. Vanlandingham; R. F. Eduljee; J. W. Gillespie; J. M. Schultz

2000-01-01

369

Band structure of polyethylene from many-body perturbation theory  

NASA Astrophysics Data System (ADS)

The electronic structure of polyethylene is an important benchmark and the infinite chain limit for the electronic properties of many molecules, monolayers, and oligomers. Therefore, the band structure of the ideal, one-dimensional polyethylene chain has been extensively researched, from both the experimental and the theoretical viewpoints. Despite this extensive effort, to the best of our knowledge agreement between theoretical calculations and the electronic structure obtained from photoelectron spectroscopy could only be obtained using artificial shifting and ``stretching'' of the computed data. Here, we present a quantitative quasi-particle band-structure for polyethylene using many-body perturbation theory. The approach is employed within the G0W0 approximation, based on a starting point calculated within the generalized gradient approximation to density functional theory. We compare our calculated band-structure to angle resolved photoemission spectroscopy measurements for various long saturated carbohydrates, demonstrate a much improved agreement with experiment, and discuss remaining discrepancies and their possible origins within both theory and experiment.

Biller, Ariel; Sharifzadeh, Sahar; Segev, Lior; Ismail-Beigi, Sohrab; Neaton, Jeffrey B.; Kronik, Leeor

2013-03-01

370

Thermomechanical Properties of the Semicrystalline Interphase of Polyethylene  

NASA Astrophysics Data System (ADS)

We present the first complete theoretical estimates for the thermal and elastic properties of the noncrystalline phase (the "interphase") of semicrystalline polyethylene obtained by Monte Carlo simulations, where polyethylene is represented by a realistic united atom force field, which includes torsional contributions. The interphase is modeled as a metastable disordered region constrained between two static crystalline layers and consists of bridge, loop and tail populations of varying lengths. Parallel tempering is used to simulate several isochoric/isothermal ensembles simultaneously and efficiently. Both energetic and entropic contributions to elastic moduli are calculated, the latter indirectly obtained through virial pressure calculations. The interphase region of real polyethylene, characterized by density, order and energy profiles, is compared to earlier work on freely rotating chains [Balijepalli and Rutledge, J. Chem. Phys. 1998, 6523]. The isochoric and isobaric heat capacities, Grueneisen coefficients, thermal expansion and elastic stiffness constants are reported. The interphase exhibits material properties comparable to that of the corresponding melt, with significant contributions of both enthalpic and entropic origins.

in't Veld, Pieter J.; Rutledge, Gregory C.

2004-03-01

371

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

372

Polyethylene Wear Is Influenced by Manufacturing Technique in Modular TKA  

PubMed Central

Polyethylene insert backside surface wear is implicated in osteolysis and failure of total knee arthroplasty. Manufacturing and sterilization methods reduce articular-sided wear. We questioned whether manufacturing technique influences the severity of backside wear. We examined 39 explanted tibial bearings in a blinded fashion using visual, stereomicroscopic, and scanning electron microscopic techniques. We examined 26 direct compression molded components and 13 nondirect compression molded components and applied a new backside wear severity score. The score characterized the magnitude of the various modes of wear with severity ranging from 0 (no wear) to 27 (severe wear). Time in vivo, tibial baseplate material, and manufacturing technique were used as variables for comparison. Backside wear was related to polyethylene manufacturing process with direct compression molded implants having a wear score of 2.3 and nondirect compression molded a score of 5.7. Time in vivo influenced backside wear, although direct compression molded predicted decreased backside wear independent of time in vivo. The data suggest manufacturing technique influences backside wear in total knee arthroplasty polyethylene inserts.

Ellison, Bradley S.; Berend, Keith R.

2008-01-01

373

Trapping of excitons at chemical defects in polyethylene  

NASA Astrophysics Data System (ADS)

In a previous paper we studied an injected electron-hole pair in crystalline polyethylene (PE) and found that the exciton becomes weakly self-trapped in a narrow interchain pocket comprised between two gauche defects. Despite the large energy stored in the trapped excitation, there did not appear to be a direct nonradiative channel for electron-hole recombination. Actual polyethylene systems of practical use are, however, neither crystalline nor pure. To understand the fate of an electron-hole pair in the impure case, we studied by ab initio simulations the evolution of an exciton trapped on three common chemical defects found in polyethylene: a grafted carbonyl (C=O) an intrachain vinyl group (C=C) a grafted carboxyl (COOH). Ab initio simulations lead to predict three different outcomes: trapping, nonradiative recombination, and homolitic bond-breaking, respectively. This suggests that extrinsic self-trapping of electron-hole pairs over chemical defects inside the quasicrystalline fraction of PE could be relevant for electrical damage in high-voltage cables.

Ceresoli, D.; Tosatti, E.; Scandolo, S.; Santoro, G.; Serra, S.

2004-10-01

374

An improved synthesis of a fluorophosphonate-polyethylene glycol-biotin probe and its use against competitive substrates  

PubMed Central

Summary The fluorophosphonate (FP) moiety attached to a biotin tag is a prototype chemical probe used to quantitatively analyze and enrich active serine hydrolases in complex proteomes in an approach called activity-based protein profiling (ABPP). In this study we have designed a novel synthetic route to a known FP probe linked by polyethylene glycol to a biotin tag (FP–PEG–biotin). Our route markedly increases the efficiency of the probe synthesis and overcomes several problems of a prior synthesis. As a proof of principle, FP–PEG–biotin was evaluated against isolated protein mixtures and different rat-tissue homogenates, showing its ability to specifically target serine hydrolases. We also assessed the ability of FP–PEG–biotin to compete with substrates that have high enzyme turnover rates. The reduced protein-band intensities resulting in these competition studies demonstrate a new application of FP-based probes seldom explored before.

Amidon, Gordon L

2013-01-01

375

41—THE EFFECTS OF A POLYETHYLENE OXIDE CONDENSATE AND SOME POLYETHYLENE GLYCOLS ON THE ABSORPTION SPECTRA OF CERTAIN AZO DYES  

Microsoft Academic Search

The presence of Dispersol A, a polyethylene oxide condensate, in an aqueous 1O mg.\\/l. Benzopurpurine 4B solution has a considerable effect upon the absorption spectrum of the dye. The spectral effect is similar to that of pyridine, and is independent of the Dispersol A concentration over the range 0·5 to 10 per cent. The absorption spectra of the dye (10

J. T. Martin; H. A. Standing

1949-01-01

376

Use of Hydrophilic Polymer Coatings for Control of Electroosmosis and Protein Adsorption.  

National Technical Information Service (NTIS)

The purpose of this project was to examine the utility of polyethylene glycol (PEG) and dextran coatings for control of electroosmosis and protein adsorption; electroosmosis is an important, deleterious process affecting electrophoretic separations, and p...

J. M. Harris

1987-01-01

377

Synthesis, characterization and assessment of suitability of trehalose fatty acid esters as alternatives for polysorbates in protein formulation  

Microsoft Academic Search

Nonionic polyethylene glycol-derived surfactants are today’s choice as surfactants in protein formulations. Different groups discovered that although surface-induced stresses are reduced by these excipients, the long-term stability of different proteins decreased due to polyethylene glycol-related induction of oxidation processes under static storage conditions. In this paper, the potential of polyoxyethylene-free surfactants for protein formulation was evaluated. Three different sugar-based surfactants,

L. Schiefelbein; M. Keller; F. Weissmann; M. Luber; F. Bracher; W. Frieß

2010-01-01

378

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

379

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

2012-02-09

380

Five-year comparative study of highly cross-linked (crossfire) and traditional polyethylene.  

PubMed

The purpose of this study was to compare the linear penetration rates of a highly cross-linked ultra-high-molecular-weight polyethylene to traditional polyethylene. Twenty-seven highly cross-linked components were matched to 27 traditional polyethylene components with respect to age, sex, body mass index, and activity level. Each group was followed up for a mean of approximately 6 years. Linear penetration was measured using Martell's computerized technique (J Bone Joint Surg Am 1997;79:1635). The mean total penetration was 0.283 mm (SD, 0.253) for the highly cross-linked group. The mean total penetration for the traditional polyethylene was 0.696 mm (SD, 0.402). This difference was highly significant (P < or = .001). Our experience demonstrates a 59% reduction in total penetration of highly cross-linked polyethylene when compared with traditional polyethylene at a minimum of 5 years. PMID:18534491

Rajadhyaksha, Amar D; Brotea, Cristian; Cheung, Yeukkei; Kuhn, Courtney; Ramakrishnan, Rama; Zelicof, Steven B

2008-03-04

381

Layering isotherms on silicon: Kinetics and equilibrium modeling of protein adsorption  

Microsoft Academic Search

Current modeling of protein adsorption encompasses considerations in protein physical chemistry including conformation change. Current models have failed to predict experimental observation of monotonic growth in protein adsorption to unmodified hydrophilic silicon surfaces during the experimental time period, and its abolition by surface modification with polyethylene glycol (PEG). The objective of the abstracted modeling is improving understanding of protein adsorption

Ofer Isaac Matalon

1999-01-01

382

Modification of recombinant asparaginase from Erwinia carotovora with polyethylene glycol 5000  

Microsoft Academic Search

A method for polyethylene conjugation with recombinant asparaginase has been developed to improve therapeutically important\\u000a properties of enzyme. Methoxy-p-nitrophenyl carbamate of polyethylene glycol with molecular weight 5000 was employed as the modification reagent. Optimization\\u000a of the pegylation procedure resulted in high level of enzyme modification. Under 4.5 molar excess of the modification reagent\\u000a more than 10 molecules of methoxy-polyethylene bound

A. V. Kuchumova; Y. V. Krasotkina; P. Z. Khasigov; N. N. Sokolov

2007-01-01

383

Five-Year Comparative Study of Highly Cross-Linked (Crossfire) and Traditional Polyethylene  

Microsoft Academic Search

The purpose of this study was to compare the linear penetration rates of a highly cross-linked ultra–high-molecular-weight polyethylene to traditional polyethylene. Twenty-seven highly cross-linked components were matched to 27 traditional polyethylene components with respect to age, sex, body mass index, and activity level. Each group was followed up for a mean of approximately 6 years. Linear penetration was measured using

Amar D. Rajadhyaksha; Cristian Brotea; Yeukkei Cheung; Courtney Kuhn; Rama Ramakrishnan; Steven B. Zelicof

2009-01-01

384

Modification of water vapour transfer rate of low density polyethylene films for food packaging  

Microsoft Academic Search

One of the most common materials used for packaging is low density polyethylene film. To improve the water vapour transfer of the film, zeolite–polymer composite films and perforated films are produced. The solid–low density polyethylene composite films were prepared by extrusion of polyethylene beads coated with hot zeolite particles of a definite size range in an industrial extruder (?420\\/+212, ?212\\/+106,

S. Nur Dirim; H. Özlem Özden; Alev Bay?nd?rl?; Ali Esin

2004-01-01

385

On the compatibility of low density polyethylene\\/hydrolyzed collagen blends. II: New compatibilizers  

Microsoft Academic Search

Compatibility\\/compatibilization of low density polyethylene (LDPE) and hydrolyzed collagen (HC) in the presence of some reactive compatibilizing agents (CA), like acrylic acid functionalized low density polyethylene (LDPE-g-AAc) and bismaleinimide-functionalized low density polyethylene (LDPE-g-BMI) have been discussed. It has been established that, by 20–30wt% HC incorporation in LDPE matrix, in the presence of LDPE-g-AAc and LDPE-g-BMI compatibilizing agents, materials with good

Mihaela C. Dasc?lu; Cornelia Vasile; Clara Silvestre; Mihaela Pascu

2005-01-01

386

Experimental and numerical study of entry flow of low-density polyethylene melts  

Microsoft Academic Search

The present work deals with experimental and numerical features of entry flows of two polyethylene melts, namely a linear low-density polyethylene (LLDPE) and a low-density polyethylene (LDPE) in an axisymmetric converging geometry. The study also involves rheological characterization of the polymers and determination of flow parameters, at 160°C. For both fluids, the data are fed into a viscoelastic integral Wagner

Jacques Guillet; Pascale Revenu; Yves Béreaux; Jean-Robert Clermont

1996-01-01

387

The crystallization of low-density polyethylene: a molecular dynamics simulation  

Microsoft Academic Search

Three models (star-shaped, H-shaped, and comb-shaped polyethylenes) are used to study the crystallization behavior of low-density polyethylene at the molecular level by means of molecular dynamics simulation. It is shown that, for the three types of polyethylene corresponding to the models, the neighboring sequences of trans bonds firstly aggregate together to form local ordered domains, and then they coalesce to

Xiu-bin Zhang; Ze-sheng Li; Zhong-yuan Lu; Chia-Chung Sun

2002-01-01

388

Synthesis and characterization of novel comb-type amphiphilic graft copolymers containing polypropylene and polyethylene glycol  

Microsoft Academic Search

Amphiphilic comb-type graft copolymers containing polypropylene (PP) and polyethylene glycol (PEG) have been prepared. Polypropylene-g-polyethylene glycol comb-type thermoplastic amphiphilic copolymers were synthesized by the reaction between chlorinated polypropylene\\u000a and polyethylene glycol in the presence of a base via a “grafting to” technique. A series of graft copolymers containing PEGs\\u000a with molecular weights of 600 and 2,000 Da in the range of

Murat Balc?; Abdulkadir All?; Baki Hazer; Olgun Güven; Kevin Cavicchi; Mukerrem Cakmak

2010-01-01

389

Gas chromatographic study of the volatile products from co-pyrolysis of coal and polyethylene wastes  

Microsoft Academic Search

The aim of this study was to determine the volatile products distribution of co-processing of coal with two plastic wastes, low-density polyethylene from agriculture greenhouses and high-density polyethylene from domestic uses, in order to explain the observed decrease in coal fluidity caused by polyethylene waste addition. Polymeric materials, although they are not volatile themselves, may be analysed by gas chromatography

A Dom??nguez; C. G Blanco; C Barriocanal; R Alvarez; M. A D??ez

2001-01-01

390

Partitioning of polycyclic aromatic hydrocarbons in the polyethylene\\/water system  

Microsoft Academic Search

The suitability of polyethylene sheets as passive samplers of lipophilic contaminants in water bodies was tested. High-density polyethylene (HDPE) and low-density polyethylene (LDPE) sheets were contaminated with PAH. Uncontaminated and pre-contaminated sheets were deployed simultaneously and collected at intervals over 32 days. The exposed sheets and water samples were analyzed for PAH. The initial PAH concentrations in the contaminated and

Jochen F. Müller; K. Manomanii; Munro R. Mortimer; Michael S. McLachlan

2001-01-01

391

Adsorption of polyethylene standards from decalin on liquid chromatography column packings  

Microsoft Academic Search

Linear polyethylene and isotactic polypropylene standards were injected into columns which contained MFI (SH-300 and silicalite) or faujasite (CBV-780) type zeolites. 1,2,4-Trichlorobenzene, cyclohexanone, 2-ethyl-hexanol, decalin and tetralin were used as mobile phases at 140°C. It was found that polyethylene is fully retained on zeolite SH-300 when decalin is used as a mobile phase. Moreover, polyethylene is partially retained on zeolite

Tibor Macko; Harald Pasch; Joeri F. Denayer

2003-01-01

392

Ceramic Head Fracture in Ceramic-on-Polyethylene Total Hip Arthroplasty.  

PubMed

Revision rates of total hip arthroplasty have decreased after introducing total hip arthroplasty (THA) using ceramic component, since ceramic components could reduce components wear and osteolysis. The fracture of a ceramic component is a rare but potentially serious event. Thus, ceramic on polyethylene articulation is gradually spotlighted to reduce ceramic component fracture. There are a few recent reports of ceramic head fracture with polyethylene liner. Herein, we describe a case of a ceramic head component fracture with polyethylene liner. The fractured ceramic head was 28 mm short neck with conventional polyethylene liner. We treated the patient by total revision arthroplasty using 4th generation ceramic on ceramic components. PMID:24142666

Nho, Jae-Hwi; Park, Jong-Seok; Song, Ui-Seoub; Kim, Woo-Jong; Suh, You-Sung

2013-11-01

393

Ceramic Head Fracture in Ceramic-on-Polyethylene Total Hip Arthroplasty  

PubMed Central

Revision rates of total hip arthroplasty have decreased after introducing total hip arthroplasty (THA) using ceramic component, since ceramic components could reduce components wear and osteolysis. The fracture of a ceramic component is a rare but potentially serious event. Thus, ceramic on polyethylene articulation is gradually spotlighted to reduce ceramic component fracture. There are a few recent reports of ceramic head fracture with polyethylene liner. Herein, we describe a case of a ceramic head component fracture with polyethylene liner. The fractured ceramic head was 28 mm short neck with conventional polyethylene liner. We treated the patient by total revision arthroplasty using 4th generation ceramic on ceramic components.

Nho, Jae-Hwi; Song, Ui-Seoub; Kim, Woo-Jong; Suh, You-Sung

2013-01-01

394

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

395

Adhesion, growth, and maturation of vascular smooth muscle cells on low-density polyethylene grafted with bioactive substances.  

PubMed

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. PMID:23586032

Parizek, Martin; Slepickova Kasalkova, Nikola; Bacakova, Lucie; Svindrych, Zdenek; Slepicka, Petr; Bacakova, Marketa; Lisa, Vera; Svorcik, Vaclav

2013-03-24

396

Tolerogenic activity of polyethylene glycol-conjugated lysozyme distinct from that of the native counterpart.  

PubMed Central

Conjugation of proteins with polyethylene glycol (PEG) has been reported to make the proteins tolerogenic. Native proteins are also potentially tolerogenic when given without adjuvants. We compared immunotolerogenic activities between PEG-conjugated and native hen egg-white lysozyme (HEL). BALB/c mice were given consecutive weekly intraperitoneal administrations of PEG-conjugated HEL, unmodified HEL or phosphate-buffered saline (PBS), for 3 weeks, then challenged with HEL in Freund's complete adjuvant. The pretreatment with PEG-HEL tolerized both T-cell and humoral responses, while native HEL tolerized only the T-cell response. Immunoglobulin G1 (IgG1) antibody was already elevated in HEL-pretreated mice prior to challenge immunization, followed by suppressed IgG2a and IgG2b, but spared IgG1 production after the antigen challenge, whereas PEG-HEL-pretreated mice produced no antibody in all IgG subclasses prior and subsequent to the antigen-challenge. Production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) by lymphoid cells in response to HEL in vitro was markedly suppressed in both the antigen-pretreated groups, while suppression of IL-4 production was evident only in PEG-HEL-, not in HEL-pretreated animals. Involvement of suppressor cells in these tolerance states was found to be unlikely, and the immunological property of PEG-HEL differed from deaggregated HEL that was similar to the original HEL. These results suggest a unique immunotolerogenic activity of PEG-conjugated proteins to suppress both T-helper type-1 (Th1)- and Th2-type responses, the result being extensive inhibition of all IgG subclass responses, while tolerance induction by unconjugated soluble proteins tends to be targeted on Th1-, but spares Th2-type responses.

Ito, H O; So, T; Hirata, M; Koga, T; Ueda, T; Imoto, T

1998-01-01

397

Growth of ZnO nanowires on nonwoven polyethylene fibers  

NASA Astrophysics Data System (ADS)

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. The growth process was carried out in a sealed chemical bath containing an equimolar solution of zinc nitrate hexahydrate and hexamethylene tetramine at a temperature of 95 °C over a period of up to 20 h. The thickness and length of the nanowires can be controlled by using different concentrations of the starting reactants and growth durations. A 0.5 mM chemical bath yielded nanowires with an average diameter of around 50 nm, while a 25 mM bath resulted in wires with a thickness of up to about 1 ?m. The length of the wires depends both on the concentration of the precursor solution as well as the growth duration, and in 20 h, nanowires as long as 10 ?m can be grown. The nonwoven mesh of polyethylene fibers covered with ZnO nanowires can be used for novel applications such as water treatment by degrading pollutants by photocatalysis. Photocatalysis tests carried out on standard test contaminants revealed that the polyethylene fibers with ZnO nanowires grown on them could accelerate the photocatalytic degradation process by a factor of 3.

Baruah, Sunandan; Thanachayanont, Chanchana; Dutta, Joydeep

2008-04-01

398

Polymer-layered silicate nanocomposites. 1. A study of poly(ethylene oxide)\\/Na +-montmorillonite nanocomposites as polyelectrolytes and polyethylene-block-poly(ethylene glycol) copolymer\\/Na +-montmorillonite nanocomposites as fillers for reinforcement of polyethylene  

Microsoft Academic Search

Poly(ethylene oxide) PEO\\/Na+-montmorillonite and polyethylene–poly(ethylene glycol) (PE–PEG) diblock copolymer\\/Na+-montmorillonite nanocomposites have been prepared by melt intercalation method. The effect of thermal treatment on the amount of PEO and PE–PEG diblock copolymer intercalated into layers of Na+-montmorillonite and on ionic conductivity of PEO\\/Na+-MMT nanocomposites have been evaluated. It was found that PEO can be intercalated into the layers of Na+-MMT by

Bing Liao; Mo Song; Haojun Liang; Yongxin Pang

2001-01-01

399

Branched carbon nanotube reinforcements for improved strength of polyethylene nanocomposites  

NASA Astrophysics Data System (ADS)

A bio-inspired design of polyethylene nanocomposites is presented in this letter using branched carbon nanotubes (BCNTs) as reinforcements. Using coarse-grained molecular dynamics simulations, we demonstrate that the pullout strength of the proposed BCNT nanofibers can be an order of magnitude higher than that of CNT reinforcements. The drastically improved interfacial shearing strength is found to be strongly dependent on the geometry of nanofibers, the molecular weight of matrix polymers, and the pullout velocity. By analyzing the time-evolving molecular configurations of BCNT nanofibers and surrounding polymer chains, the underlying strengthening mechanisms are discussed and strategies for further improvement are suggested.

Liu, Ling; Zhang, Lin; Lua, Jim

2012-10-01

400

Lithium ion transport in a model of amorphous polyethylene oxide.  

SciTech Connect

We have made a molecular dynamics study of transport of a single lithium ion in a previously reported model of amorphous polyethylene oxide. New ab initio calculations of the interaction of the lithium ion with 1,2-dimethoxyethane and with dimethyl ether are reported which are used to determine force fields for the simulation. We report preliminary calculations of solvation energies and hopping barriers and a calculation of the ionic conductivity which is independent of any assumptions about the mechanism of ion transport. We also report some details of a study of transport of the trapped lithium ion on intermediate time and length scales.

Boinske, P. T.; Curtiss, L.; Halley, J. W.; Lin, B.; Sutjianto, A.; Chemical Engineering; Univ. of Minnesota

1996-01-01

401

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

402

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

403

Buckling of carbon nanotubes wrapped by polyethylene molecules  

NASA Astrophysics Data System (ADS)

The discovery of a buckling instability of a single-walled carbon nanotube wrapped by a polyethylene molecule subjected to compression is reported through molecular mechanics simulations. A decrease up to 44% in the buckling strain of the nano-structure owing to the van der Waals interaction between the two molecules is uncovered. A continuum model is developed to calculate both the interaction between the tube and the polymer and the decreased buckling strain of the structure by fitting the molecular mechanics results.

Wang, Q.

2011-01-01

404

Polyethylenes produced with zirconocene immobilized on MAO-modified silicas  

Microsoft Academic Search

The effect of Al content on MAO-modified silicas was evaluated on catalyst activity, on polymer properties and on residual metal content in the resulting polyethylenes. MAO-modified silicas were prepared by impregnating MAO toluene solutions in concentration range between 0.5 and 20.0wt% Al\\/SiO2. Commercial MAO-modified silica (Witco) containing 24.4wt% Al\\/SiO2 was used for comparative reasons. The resulting modified-silicas were employed as

Daniela Bianchini; Kátia Messias Bichinho; Joăo Henrique Zimnoch dos Santos

2002-01-01

405

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

406

Enhanced blood compatibility of silicon coated with a self-assembled poly(ethylene glycol) and monomethoxypoly(ethylene glycol)  

NASA Astrophysics Data System (ADS)

Silicon biomedical microdevices generally require surface modifications to improve their biocompatibility. ONe of the challenges in the field is the development of molecular coatings for devices with nanofeatures.In this paper we report the results of our investigation of synthetic poly(ethylene glycol) (PEG) and monomethoxypoly(ethylene glycol) (MPEG) coatings incorporating functional groups that in turn immobilize self-assembled monolayers. The properties of the modified surfaces were characterized by ellipsometry and scanning electron microscopy. Protein adsorption as well as platelet adhesion to the treated surfaces were studied to evaluate the non-fouling property of the PEG-enriched surface layers. Both PEG- and MPEG-modified surfaces showed significant suppression in plasma protein adsorption and platelet adhesion.

Zhang, Miqin; Ferrari, Mauro

1998-03-01

407

Characterization of a cryptic plasmid, pSM103mini, from polyethylene-glycol degrading Sphingopyxis macrogoltabida strain 103.  

PubMed

A cryptic plasmid, pSM103mini, was found in polyethylene-glycol degrading bacterium Sphingopyxis macrogoltabida, strain 103. The plasmid was 4,328-bp long and its GC content was 57.5%. It contained four open reading frames, but only two of them showed significant similarity to reported proteins. ORF3 and ORF4 were assumed to encode resolvase and replication protein (RepA) respectively. Downstream of ORF4 we found complex repeat sequences. These together with ORF3 and 4 were necessary and sufficient for plasmid maintenance in strain 103, as analyzed by constructing deletion plasmids. The pHSG398-fused plasmid (pHSG-SM103mini) functioned as a shuttle vector between strain 103 and Escherichia coli. The plasmid constructed was maintained in strain 103 and its close relative, S. macrogoltabida strain 203, but not efficiently in PEG-degrading S. terrae. PMID:21307601

Tani, Akio; Tanaka, Akiyuki; Minami, Toshiyuki; Kimbara, Kazuhide; Kawai, Fusako

2011-02-07

408

The effect of polyethylene glycol on the mechanics and ATPase activity of active muscle fibers.  

PubMed

We have used polyethylene glycol (PEG) to perturb the actomyosin interaction in active skinned muscle fibers. PEG is known to potentiate protein-protein interactions, including the binding of myosin to actin. The addition of 5% w/v PEG (MW 300 or 4000) to active fibers increased fiber tension and decreased shortening velocity and ATPase activity, all by 25-40%. Variation in [ADP] or [ATP] showed that the addition of PEG had little effect on the dissociation of the cross-bridge at the end of the power stroke. Myosin complexed with ADP and the phosphate analog V(i) or AlF(4) binds weakly to actin and is an analog of a pre-power-stroke state. PEG substantially enhances binding of these states both in active fibers and in solution. Titration of force with increasing [P(i)] showed that PEG increased the free energy available to drive the power stroke by about the same amount as it increased the free energy available from the formation of the actomyosin bond. Thus PEG potentiates the binding of myosin to actin in active fibers, and it provides a method for enhancing populations of some states for structural or mechanical studies, particularly those of the normally weakly bound transient states that precede the power stroke. PMID:10653805

Chinn, M K; Myburgh, K H; Pham, T; Franks-Skiba, K; Cooke, R

2000-02-01

409

Modeling and simulation of Li-ion conduction in poly(ethylene oxide)  

NASA Astrophysics Data System (ADS)

Polyethylene oxide (PEO) containing a lithium salt (e.g., LiI) serves as a solid polymer electrolyte (SPE) in thin-film batteries and its ionic conductivity is a key parameter of their performance. We model and simulate Li+ ion conduction in a single PEO molecule. Our simplified stochastic model of ionic motion is based on an analogy between protein channels of biological membranes that conduct Na+, K+, and other ions, and the PEO helical chain that conducts Li+ ions. In contrast with protein channels and salt solutions, the PEO is both the channel and the solvent for the lithium salt (e.g., LiI). The mobile ions are treated as charged spherical Brownian particles. We simulate Smoluchowski dynamics in channels with a radius of ca. 0.1 nm and study the effect of stretching and temperature on ion conductivity. We assume that each helix (molecule) forms a random angle with the axis between these electrodes and the polymeric film is composed of many uniformly distributed oriented boxes that include molecules with the same direction. We further assume that mechanical stretching aligns the molecular structures in each box along the axis of stretching (intra-box alignment). Our model thus predicts the PEO conductivity as a function of the stretching, the salt concentration and the temperature. The computed enhancement of the ionic conductivity in the stretch direction is in good agreement with experimental results. The simulation results are also in qualitative agreement with recent theoretical and experimental results.

Gitelman, L.; Israeli, M.; Averbuch, A.; Nathan, M.; Schuss, Z.; Golodnitsky, D.

2007-12-01

410

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

2013-04-19

411

Single-monomer formulation of polymerized polyethylene glycol diacrylate as a nonadsorptive material for microfluidics.  

PubMed

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 it 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 ultraviolet (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 ?g/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 × 10(5)/m. Poly-PEGDA, which displays resistance to nonspecific adsorption, could have broad use in small volume analysis and biomedical research. PMID:21728310

Rogers, Chad I; Pagaduan, Jayson V; Nordin, Gregory P; Woolley, Adam T

2011-07-20

412

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

413

Enhancement of the predicted drug hepatotoxicity in gel entrapped hepatocytes within polysulfone-g-poly (ethylene glycol) modified hollow fiber  

SciTech Connect

Collagen gel-based 3D cultures of hepatocytes have been proposed for evaluation of drug hepatotoxicity because of their more reliability than traditional monolayer culture. The collagen gel entrapment of hepatocytes in hollow fibers has been proven to well reflect the drug hepatotoxicity in vivo but was limited by adsorption of hydrophobic drugs onto hollow fibers. This study aimed to investigate the impact of hollow fibers on hepatocyte performance and drug hepatotoxicity. Polysulfone-g-poly (ethylene glycol) (PSf-g-PEG) hollow fiber was fabricated and applied for the first time to suppress the drug adsorption. Then, the impact of hollow fibers was evaluated by detecting the hepatotoxicity of eight selected drugs to gel entrapped hepatocytes within PSf and PSf-g-PEG hollow fibers, or without hollow fibers. The hepatocytes in PSf-g-PEG hollow fiber showed the highest sensitivity to drug hepatotoxicity, while those in PSf hollow fiber and cylindrical gel without hollow fiber underestimated the hepatotoxicity due to either drug adsorption or low hepatic functions. Therefore, the 3D culture of gel entrapped hepatocytes within PSf-g-PEG hollow fiber would be a promising tool for investigation of drug hepatotoxicity in vitro.

Shen Chong [Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Zhang Guoliang [Institute of Biological and Environmental Engineering, Zhejiang University of Technology, Zhejiang 310012 (China); Meng Qin, E-mail: mengq@zju.edu.c [Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

2010-12-01

414

Modification and patterning of nanometer-thin poly(ethylene glycol) films by electron irradiation.  

PubMed

In this study, we analyzed the effect of electron irradiation on highly cross-linked and nanometer-thin poly(ethylene glycol) (PEG) films and, in combination with electron beam lithography (EBL), tested the possibility to prepare different patterns on their basis. Using several complementary spectroscopic techniques, we demonstrated that electron irradiation results in significant chemical modification and partial desorption of the PEG material. The initially well-defined films were progressively transformed in carbon-enriched and oxygen-depleted aliphatic layers with, presumably, still a high percentage of intermolecular cross-linking bonds. The modification of the films occurred very rapidly at low doses, slowed down at moderate doses, and exhibited a leveling off behavior at higher doses. On the basis of these results, we demonstrated the fabrication of wettability patterns and sculpturing complex 3D microstructures on the PEG basis. The swelling behavior of such morphological patterns was studied in detail, and it was shown that, in contrast to the pristine material, irradiated areas of the PEG films reveal an almost complete absence of the hydrogel-typical swelling behavior. The associated sealing of the irradiated areas allows a controlled deposition of objects dissolved in water, such as metal nanoparticles or fluorophores, into the surrounding, pristine areas, resulting in the formation of nanocomposite patterns. In contrast, due to the distinct protein-repelling properties of the PEG films, proteins are exclusively adsorbed onto the irradiated areas. This makes such films a suitable platform to prepare protein-affinity patterns in a protein-repelling background. PMID:23639274

Meyerbröker, Nikolaus; Zharnikov, Michael

2013-05-15

415

Medium density polyethylene composites with functionalized carbon nanotubes.  

PubMed

A strong interface between the single-walled carbon nanotubes (SWNTs) and polymer matrix is necessary to achieve enhanced mechanical properties of composites. In this work a series of sidewall-functionalized SWNTs have been investigated in order to evaluate the effect of functionalization on SWNT aspect ratio and composite interfacial chemistry and their role on mechanical properties of a medium density polyethylene (MDPE) matrix. Fluorinated nanotubes (F-SWNTs) were used as precursors for subsequent sidewall functionalization with long chain alkyl groups to produce an F-SWNT- C(11)H(23) derivative. The latter was refluorinated to yield a new perfluorinated derivative, F-SWNT- C(11)F(x)H(y). The functionalized SWNTs as well as the pristine SWNTs were integrated into an MDPE matrix at a 1 wt% loading. The nanotubes and composite materials were characterized with FTIR, Raman spectroscopy, NMR, XPS, AFM, SEM, TGA, DSC and tensile tests. When incorporated into polyethylene, the new perfluorinated derivative, F-SWNT- C(11)F(x)H(y), yielded the highest tensile strength value among all nanotube/MDPE composite samples, showing a 52% enhancement in comparison with the neat MDPE. The 1 wt% SWNT/MDPE composite contained nanotubes with a larger aspect ratio but, due to a lack of interfacial chemistry, it resulted in less improvement in mechanical properties compared to the composites made with the fluorinated SWNT derivatives. PMID:19420641

Pulikkathara, Merlyn X; Kuznetsov, Oleksandr V; Peralta, Ivana R G; Wei, Xin; Khabashesku, Valery N

2009-04-21

416

Medium density polyethylene composites with functionalized carbon nanotubes  

NASA Astrophysics Data System (ADS)

A strong interface between the single-walled carbon nanotubes (SWNTs) and polymer matrix is necessary to achieve enhanced mechanical properties of composites. In this work a series of sidewall-functionalized SWNTs have been investigated in order to evaluate the effect of functionalization on SWNT aspect ratio and composite interfacial chemistry and their role on mechanical properties of a medium density polyethylene (MDPE) matrix. Fluorinated nanotubes (F-SWNTs) were used as precursors for subsequent sidewall functionalization with long chain alkyl groups to produce an F-SWNT- C11H23 derivative. The latter was refluorinated to yield a new perfluorinated derivative, F-SWNT- C11FxHy. The functionalized SWNTs as well as the pristine SWNTs were integrated into an MDPE matrix at a 1 wt% loading. The nanotubes and composite materials were characterized with FTIR, Raman spectroscopy, NMR, XPS, AFM, SEM, TGA, DSC and tensile tests. When incorporated into polyethylene, the new perfluorinated derivative, F-SWNT- C11FxHy, yielded the highest tensile strength value among all nanotube/MDPE composite samples, showing a 52% enhancement in comparison with the neat MDPE. The 1 wt% SWNT/MDPE composite contained nanotubes with a larger aspect ratio but, due to a lack of interfacial chemistry, it resulted in less improvement in mechanical properties compared to the composites made with the fluorinated SWNT derivatives.

Pulikkathara, Merlyn X.; Kuznetsov, Oleksandr V.; Peralta, Ivana R. G.; Wei, Xin; Khabashesku, Valery N.

2009-05-01

417

Wear characteristics of ultrahigh molecular weight polyethylene (UHMWPE)  

NASA Astrophysics Data System (ADS)

The wear of ultrahigh molecular weight polyethylene (UHMWPE) bearing against 316 stainless steel or cobalt chromium (Co-Cr) alloy was measured using a 12-channel wear tester especially developed for the evaluation of candidate materials for prosthetic joints. The coefficient of friction and wear rate were determined as a function of lubricant, contact stress, and metallic surface roughness in tests lasting 2 3 million cycles, the equivalent of several years use of a prosthesis. Wear was determined by the weight loss of the polyethylene (PE) specimens corrected for the effect of fluid absorption. The friction and wear processes in blood serum differed markedly from those in saline solution or distilled water. Only serum lubrication produced wear surfaces resembling those observed on removed prostheses. The experimental methods provided accurate reproducible measurement of PE wear. The long-term wear rates were proportional to load and sliding distance. Although the PE wear rate increased with increasing surface roughness, wear was not severe except with very coarse metal surfaces. The data obtained in these studies formed a comparison basis for the subsequent evaluation of potentially superior materials for prosthetic joints.

El-Domiaty, A.; El-Fadaly, M.; Nassef, A. Es.

2002-10-01

418

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

2012-11-07

419

[Abrasion reducing polyethylene ceramic-metal compound hip prosthesis head].  

PubMed

There are two specific problems in using metallic or ceramic heads for hip prostheses: (1) the amount of polyethylene abrasions in the cup caused by the heads (especially a metal head). (2) the polyethylene abrasions caused by Al2O3 ceramic heads is far less than metal heads, but its ability to adapt geometrically is limited due to its being less strong. The abrasions appear because of geometric differences in the prosthetic joint, local problems in the surface architecture and physical/chemical interactions between the different materials. In this study we compare the new "Titan-Niob Ceramic Multilayer Sandwich Head" (built three layers of microsegregation phases and three in-between layers of ultrathin metal, 8-10 microns thick, and a surface with integrated grease holes) with the common CoCrMo heads and Al2O3 ceramic heads. Testing 2,000,000 cycles in a bodylike liquid under permanent loads of 90 kPa, periodically increasing up to 250 kPa, simulating normal stress situations (i.e., walking), the "Titan-Niob Ceramic Multilayer Sandwich Head" showed major advantages over the metal heads and also over the ceramic heads even though the ceramic head has been accepted so far to have the best friction coefficient. Furthermore, there has been no problem in surface fracture with the "Titan-Niob Ceramic Multilayer Sandwich Head". PMID:7502087

Hennig, F F; Repenning, D

1995-10-01

420

Study of special birefringence in low density blown polyethylene films  

NASA Astrophysics Data System (ADS)

We begin by presenting a known experimental method that uses a Babinet compensator to measure the birefringence values in five samples of low density blown polyethylene thin films. Their behaviour in the determination or confirmation of the angular values of its neutral lines is anomalous, prompting the need for a theoretical model based on the framework of Jones's theory. To make the theoretical model easier to understand and explain, we opted to present it in six stages: from the simplest unreal case -- an ideal phase plate with two cross-bred linear polarizers -- to the most complex real case -- a real Babinet compensator with a real phase plate near both cross-bred linear polarizers. In this way we can both explain the anomalies arising in determination and confirm the exactness of the zero equations obtained to justify those solutions consistent with the experimental data. This theoretical model explains the problem of the behaviour of birefringence measurements in low density blown polyethylene thin films and other blown polymeric materials.

Y Palacian, Jose Miguel Boix

421

Characterization of radiation-crosslinked, high-density polyethylene  

SciTech Connect

Crystalline, form-stable, high-density polyethylene (HDPE) pellets were previously developed for thermal energy storage. The present study is directed toward characterization of the crosslinked, form-stable HDPE pellets produced by electron beam radiation crosslinking, and the effects of crosslinking on crystallinity and heat of fusion. Calorimetric measurements of the heats of fusion (..delta..H/sub f/) of the radiation-crosslinked HDPE (in dosages of 4 to 18 Mrad) showed that while a substantial decrease in ..delta..H/sub f/ occurred after the first melting cycle (up to approx. 25%), slow cooling (1.25/sup 0/C/min) on recrystallization of the pellets could restore the ..delta..H/sub f/ value to 95% of that of the uncrosslinked HDPE up to 9.0 Mrad dosage exposure. The form stability of the 9.0-Mrad HDPE was very good even after 500 melt-freeze cycles in ethylenes glycol. However, some further decline in ..delta..H/sub f/ was noted along with an increase in gel content at the end of the 500 cycles. X-ray diffraction measurements showed little or no difference in crystallinity among the various radiation-crosslinked HDPE's and the uncrosslinked control HDPE, indicating the crosslinking occurs primarily in the amorphous regions of the polyethylene.

Whitaker, R.B.; Craven, S.M.; Etter, D.E.; Jendrek, E.F.; Nease, A.

1981-01-01

422

Polyethylene encapsulation of single shell tank low-level wastes  

SciTech Connect

Polyethylene encapsulation is being explored for potential use in treating nitrate salts and sludges at US Department of Energy (US DOE) underground storage tank facilities. Some of these wastes contain high concentrations of fission products and are expected to maintain equilibrium temperatures of 50--70{degrees}C for many years. The potential effects of elevated temperature and high radiation conditions on key waste form properties (e.g., mechanical integrity, leachability) are examined. After 6 months of thermal conditioning, waste form tests specimens show no degradation in mechanical integrity. Leaching at elevated temperature resulted in a small increase in leach rate (a factor of less than two), while diffusion remained the dominant mechanism of release. Full-scale polyethylene waste forms containing 50--70 wt % nitrate salt can be expected to leach a total of 5--17% of the original contaminant source term after 300 years of leaching under worst-case conditions (fully saturated at 70{degrees}C).

Kalb, P.D.; Fuhrmann, M.; Colombo, P.

1993-04-01

423

Polyethylene encapsulation of single shell tank low-level wastes  

SciTech Connect

Polyethylene encapsulation is being explored for potential use in treating nitrate salts and sludges at US Department of Energy (US DOE) underground storage tank facilities. Some of these wastes contain high concentrations of fission products and are expected to maintain equilibrium temperatures of 50--70[degrees]C for many years. The potential effects of elevated temperature and high radiation conditions on key waste form properties (e.g., mechanical integrity, leachability) are examined. After 6 months of thermal conditioning, waste form tests specimens show no degradation in mechanical integrity. Leaching at elevated temperature resulted in a small increase in leach rate (a factor of less than two), while diffusion remained the dominant mechanism of release. Full-scale polyethylene waste forms containing 50--70 wt % nitrate salt can be expected to leach a total of 5--17% of the original contaminant source term after 300 years of leaching under worst-case conditions (fully saturated at 70[degrees]C).

Kalb, P.D.; Fuhrmann, M.; Colombo, P.

1993-01-01

424

Measurement of radon diffusion in polyethylene based on alpha detection  

NASA Astrophysics Data System (ADS)

Radon diffusion in different materials has been measured in the past. Usually the diffusion measurements are based on a direct determination of the amount of radon that diffuses through a thin layer of material. Here we present a method based on the measurement of the radon daughter products which are deposited inside the material. Looking at the decay of 210Po allows us to directly measure the exponential diffusion profile characterized by the diffusion length. In addition we can determine the solubility of radon in PE. We also describe a second method to determine the diffusion constant based on the short-lived radon daughter products 218Po and 214Po, using the identical experimental setup.Measurements for regular polyethylene (PE) and High Molecular Weight Polyethylene (HMWPE) yielded diffusion lengths of (1.3±0.3) mm and (0.8±0.2) mm and solubilities of 0.5±0.1 and 0.7±0.2, respectively, for the first method; the diffusion lengths extracted from the second method are noticeably larger which may be caused by different experimental conditions during diffusion.

Rau, Wolfgang

2012-02-01

425

Nanoparticle surface modification induced space charge suppression in linear low density polyethylene  

Microsoft Academic Search

This letter reports the role of nanoparticle surface modification in affecting the space charge distribution of polyethylene\\/silica nanocomposite dielectrics. Space charge distribution in the nanocomposites was measured using a pulsed electroacoustic method. The results suggested that the nanoparticle surface modification has significant effects on the space charge behaviors in polyethylene and that the nanocomposites with surface-treated silica showed improved space

Xingyi Huang; Pingkai Jiang; Yi Yin

2009-01-01

426

Mechanical Properties and Compatibility of High Density Polyethylene with Some Oligoesters  

Microsoft Academic Search

Miscibility of high density polyethylene and modifiers was evaluated using polymer-polymer interaction parameter and determined with the help of inverse gas chromatography. Mechanical, rheological properties and melting point changes were investigated. Measurements of mechanical properties showed that alloying of high density polyethylene with different oligoesters may produce higher strength and elongation than pure PE. The results obtained showed that compatibility

I. Yu. Gorbunova; M. L. Kerber; O. K. Barashkov; A. V. Stepanova

1994-01-01

427

Removal of polycyclic aromatic hydrocarbons from water by migration into polyethylene  

Microsoft Academic Search

Water was spiked with three polycyclic aromatic hydrocarbons (PAHs) and filled into a steel diffusion chamber. Low-density polyethylene sheet combined of five polyethylene foils was used as a partition in the chamber. Depth of PAHs migration into the sheet was followed for 143 h, using high performance liquid chromatography with selective fluorimetric detection after extraction of PAHs from the foils

P. Šimko; P. Šimon; V. Khunova

1999-01-01

428

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

429

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

Federal Register 2010, 2011, 2012, 2013

...garbage bags, lawn bags, trash-can liners...Polyethylene Retail Carrier Bag Committee and its individual...33773-74), to Euro Plastics Malaysia Sdn. Bhd...cash-deposit rate for Euro Plastics will be 101.74 percent...Polyethylene Retail Carrier Bags From Malaysia, 69...

2010-10-04

430

Effect of polyethylene component thickness on range of motion and stability in primary total knee arthroplasty.  

PubMed

Total knee arthroplasty (TKA) is a common procedure with good survivorship and functional results. Optimal results are dependent on proper osseous cuts and soft tissue balancing. Soft tissue tensioning via the polyethylene spacer thickness is an important component of soft tissue balancing. Increased thickness increases soft tissue tension and, therefore, has the potential to increase stability but decrease range of motion (ROM). Decreased polyethylene thickness may decrease soft tissue tension and has the potential to increase ROM but decrease stability. Using computer-based navigation, the intraoperative effect of increasing and decreasing polyethylene thickness in 1-mm increments on ROM and coronal stability throughout the ROM of 35 patients was examined. It was found that increasing the polyethylene thickness by 1-mm increments had a statistically significant impact on the ability to achieve full extension but had no impact on flexion. Increased polyethylene thickness decreased coronal plane motion. Coronal plane laxity increased with increased flexion irrespective of polyethylene thickness. In this patient cohort, lateral laxity became >1° when the knee was flexed. However, medial structures prevented valgus angulation of >1° in all scenarios except when the polyethylene was diminished by 2 mm. Changes in polyethylene thickness had an impact on the ability to gain full extension and coronal plane motion. PMID:22310401

Lanting, Brent A; Snider, Matthew G; Chess, David G

2012-02-17

431

High Thermal Conductivity of Single Polyethylene Chains Using Molecular Dynamics Simulations  

Microsoft Academic Search

We use molecular dynamics simulations to calculate the thermal conductivity of single polyethylene chains employing both the Green-Kubo approach and a modal decomposition method. Although bulk polyethylene is a thermal insulator, our results suggest that the thermal conductivity of an individual polymer chain can be very high, even divergent in some cases. Our results suggest that polymers can be engineered

Asegun Henry; Gang Chen

2008-01-01

432

2006 Otto Aufranc Award Paper: significance of in vivo degradation for polyethylene in total hip arthroplasty.  

PubMed

Our research group developed an implant retrieval program to study in vivo degradation of polyethylene. We now have evidence to support our hypothesis that degradation of radiation-sterilized polyethylene occurs in the body for not only historical gamma air sterilized liners, but also for conventional gamma inert sterilized (ArCom) and annealed highly crosslinked polyethylene (Crossfire) liners as well. Our research has also led to the discovery that the most severe manifestations of in vivo oxidation typically occur in regions of the liner experiencing minimal wear, such as the rim of the component, where the body fluids (containing oxidizing species) have access to the polyethylene. Our data from historical, ArCom, and Crossfire retrievals all point to a similar scenario in which the femoral head limits the in vivo oxidation of polyethylene at the bearing surface. Consequently, provided rim impingement does not occur, and the polyethylene locking mechanisms remain relatively isolated from oxidizing fluid, in vivo oxidation does not seem to be clinically important in the first 10 years of implantation for conventional gamma sterilized polyethylene. We conclude that in vivo degradation should be included among the list of potential long-term failure modes for modular polyethylene components for total hip arthroplasty. PMID:17031310

Kurtz, Steven M; Hozack, William J; Purtill, James J; Marcolongo, Michele; Kraay, Matthew J; Goldberg, Victor M; Sharkey, Peter F; Parvizi, Javad; Rimnac, Clare M; Edidin, Avram A

2006-12-01

433

Platelet deposition studies on copolyether urethanes modified with poly(ethylene oxide)  

Microsoft Academic Search

Pellethane ® 2363 80A films and tubings were chemically modified and the effect of these modifications on platelet deposition was studied. Grafting of high molecular weight poly(ethylene oxide) and graft polymerization of methoxy poly(ethylene glycol) 400 methacrylate resulted in surfaces with a good water wettability. The increased hydrophilicity of these modified surfaces could be demonstrated by contact angle measurements. The

E. Brinkman; A. Foot; Does van der L; A. Bantjes

1990-01-01

434

Transferability of ASTM\\/NIST alanine–polyethylene recipe at ISS  

Microsoft Academic Search

Alanine–polyethylene solid state dosimeters were prepared at Istituto Superiore di Sanitŕ (ISS) following the recipe proposed by National Institute of Standards and Technology (NIST) with the goal of testing its transferability. Dosimeters were prepared using 95% alanine and 5% polyethylene, by weight. They are rugged and of increased sensitivity, repeatability and reproducibility as respect to the ISS alanine-paraffin pellets. Reproducibility

C. De Angelis; P. Fattibene; S. Onori; E. Petetti; A. Bartolotta; A. Sansone Santamaria

2000-01-01

435

Optimum arrangement for the neutron dose rate of an iron-polyethylene shielding system  

SciTech Connect

Integral shielding experiments using iron-polyethylene slab shields were carried out to determine an optimum arrangement for the neutron dose rate. The total thickness of the iron slabs was fixed at 32 cm, while several thicknesses of polyethylene slabs were employed as a parameter. Some measured data were analyzed by the Mone Carlo code MORSE-CG with the splitting technique.

Ueki, K.; Namito, Y.

1987-05-01

436

Obtention and evaluation of polyethylene-based solid polymer electrolyte membranes fro hydrogen production  

Microsoft Academic Search

The fabrication and testing of a polyethylene-based solid polymer electrolyte for use in hydrogen production by water electrolysis are discussed. The fabrication process involves the radiation grafting of styrene groups onto a polyethylene matrix, followed by the chemical sulphonation of the resulting polymer. The membrane produced has exhibited resistivities as low as 60 ohm cm for a 1-mm thickness, and

J. P. Masson; R. Molina; E. Roth; G. Gaussens; F. Lemaire

1981-01-01

437

Electrodes and charge injection in low-density polyethylene using the pulsed electroacoustic technique  

Microsoft Academic Search

The effects of electrode materials on space charge formation in low-density polyethylene (LDPE) have been investigated experimentally using the pulsed electroacoustic (PEA) technique. Common electrode materials used in either the laboratory or power cable industry were selected, i.e. aluminum, gold and carbon loaded crosslinked polyethylene (XLPE), and space charge accumulation after the application of high electric stress was monitored. Experimental

G. Chen; T. Y. G. Tay; A. E. Davies; Y. Tanaka; T. Takada

2001-01-01

438

Pseudo-Spherulite Structures in Cross-Linked Low-Density Polyethylene  

Microsoft Academic Search

This paper describes evidence for the formation of secondary fissure structures, in low-density polyethylene (PE), and in cross-linked polyethylene (XLPE). These structures can be observed by optical and by scanning electron microscope techniques. The secondary fissures are not a volume effect like spherulites, but are associated with the fracture surface only. An explanation of this effect is given, as well

Heinz Wagner

1978-01-01

439

Improvement of adhesion properties of low density polyethylene (LDPE) substrate using atmospheric plasma  

Microsoft Academic Search

In this work we have used atmospheric plasma technology on polyethylene surface with different treatment conditions. These modify surface pre-treatments on polyethylene, thus having a positive effect on overall surface activity of polymer surface and, consequently, adhesion properties can be remarkably improved. We have evaluated the influence of the nozzle\\/substrate distance and atmospheric plasma speed on wettability changes and adhesion

L. Sánchez-Nácher; D. García-Sanoguera; O. Fenollar; J. Balart; V. Fombuena

2010-01-01

440

The Effects of Partially Filled Polyethylene Tube Intraosseous Implants in Rats.  

National Technical Information Service (NTIS)

Polyethylene tubes obturated flush at one end and 1 mm short at the opposite end with gutta percha and Grossman's cement as the cementing media were implanted in rat tibias. The gutta percha, the set Grossman's cement and the polyethylene implant were wel...

J. S. Wenger P. J. Tsaknis C. E. del Rio W. A. Ayer

1977-01-01

441

High-molecular-weight polyethylene glycol prevents lethal sepsis due to intestinal Pseudomonas aeruginosa  

Microsoft Academic Search

Background & Aims: During stress, erosion of protective intestinal mucus occurs in association with adherence to and disruption of the intestinal epithelial barrier by invading opportunistic microbial pathogens. The aims of this study were to test the ability of a high-molecular-weight polyethylene glycol compound, polyethylene glycol 15–20, to protect the intestinal epithelium against microbial invasion during stress. Methods: The ability

Licheng Wu; Olga Zaborina; Alex Zaborin; Eugene B. Chang; Mark Musch; Christopher Holbrook; James Shapiro; Jerrold R. Turner; Guohui Wu; Ka yee C. Lee; John C. Alverdy

2004-01-01

442

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

443

Impact of gamma sterilization on clinical performance of polyethylene in the knee  

Microsoft Academic Search

Damage and rapid wear of the ultrahigh-molecular-weight polyethylene bearings of knee components continue to be major sources of failure of knee prostheses. Despite considerable research into the roles of design, polyethylene thickness and quality, and component alignment, the source of the rapid wear failures has remained a mystery. This study documents elevated oxidation resulting from the use of gamma sterilization

John P. Collier; Daniel K. Sperling; John H. Currier; Lauren C. Sutula; Kenneth A. Saum; Michael B. Mayor

1996-01-01

444

Protoplast Fusion in Banana ( Musa spp.): Comparison of Chemical (PEG: Polyethylene Glycol) and Electrical Procedure  

Microsoft Academic Search

Optimization of protoplast fusion parameters is a prerequisite for the establishment of somatic fusion technology for banana breeding. In the present investigations, we compared the most frequently used fusion methods: the electrofusion technique and chemical procedure (polyethylene glycol). With regard to frequency of binary fusion, protoplast fusion with the fusogen polyethylene glycol was best. Conversely, electric fusion was found to

Akym Assani; Djamila Chabane; Robert Haďcour; Frédéric Bakry; Gerhard Wenzel; Bärbel Foroughi-Wehr

2005-01-01

445

Electron beam initiated grafting of trimethylol propane trimethacrylate onto polyethylene-structure and properties  

NASA Astrophysics Data System (ADS)

Electron beam initiated grafting of trimethylol propane trimethylacrylate (TMPTA) onto polyethylene was carried out over a range of irradiation doses (5-20 Mrad) and concentrations of TMPTA (2-6 parts by weight). The structure of the modified polyethylene was determined using IR spectroscopy, differential thermal analysis and swelling resistance. A correlation between the structure and the tensile and dielectric properties was attempted.

Tikku, V. K.; Biswas, G.; Despande, R. S.; Majali, A. B.; Chaki, T. K.; Bhowmick, Anil K.

1995-05-01

446

Influence of poly(ethylene glycol)methacrylate on the morphology and conductivity of poly(ethylene oxide)-sodium thiocyanate complexes  

Microsoft Academic Search

The effect of the introduction of poly(ethylene glycol)methacrylate (PEGMA) on structural, thermal and electrical properties of solid electrolytes based on poly(ethylene oxide) (PEO) and sodium thiocyanate, is investigated by means of calorimetric, mechanical, X-ray diffraction and conductivity measurements. PEO-PEGMA systems show in general a lower value of the glass transition temperature as compared with pure PEO. The crystallinity of the

G. Di Marco; M. Lanza; M. Pieruccini

1996-01-01

447

Study of the Gelation Process of Polyethylene Oxide a–Polypropylene Oxide b–Polyethylene Oxide aCopolymer (Poloxamer 407) Aqueous Solutions  

Microsoft Academic Search

The gelation process of polyethylene oxidea–polypropylene oxideb–polyethylene oxideacopolymer (poloxamer 407) aqueous solutions is studied by means of FTIR spectroscopy, rheology, and differential scanning calorimetry (DSC). The C–O–C stretching bands of infrared spectra were found to shift toward higher wavenumbers with sol–gel transition, indicating that hydrogen bonding is not the driving force for gelation. Linear viscoelastic data provide an alternative method

Alain Cabana; Julianna Juhász

1997-01-01

448

The effect of metallocene-catalyzed linear low-density polyethylene on the physicomechanical properties of its film blends with low-density polyethylene  

Microsoft Academic Search

Films comprising a metallocene-catalyzed linear low-density polyethylene (mLLDPE) blended with either of two different low-density polyethylene (LDPE) materials were prepared. The physicomechanical, optical and melt flow properties of the films were measured. A novel adaptation of conventional radar plots was used to process the acquired data to identify the level at which mLLDPE should be incorporated in either of the

M. J. CRAN; S. W. BIGGER

2005-01-01

449

Unexpected molecular weight dependence of shish-kebab structure in the oriented linear low density polyethylene\\/high density polyethylene blends  

Microsoft Academic Search

In this study, highly oriented shish-kebab structure was achieved via imposing oscillatory shear on the melts of linear low density polyethylene (LLDPE)\\/high density polyethylene (HDPE) blends during the packing stage of injection molding. To investigate the effect of molecular weight of HDPE on the formation of shish-kebab structure, two kinds HDPE with large melt flow index (low molecular weight) and

Si Liang; Ke Wang; Changyu Tang; Qin Zhang; Rongni Du; Qiang Fu

2008-01-01

450

Temperature modulated DSC studies of melting and recrystallization in poly(ethylene-2,6-naphthalene dicarboxylate) (PEN) and blends with poly(ethylene terephthalate) (PET)  

Microsoft Academic Search

The thermal properties of amorphous and melt crystallized poly(ethylene-2,6-naphthalene dicarboxylate) (PEN) and its blends with poly(ethylene terephthalate) (PET) were investigated. Temperature modulated DSC (TMDSC) was used over a broad range of annealing times and temperatures. PEN under all moderate temperature crystallization conditions was found to exhibit secondary crystal melting in the low endotherm region, followed by melting of primary crystals

William G. Kampert; Bryan B. Sauer

2001-01-01

451

40 CFR 721.10472 - 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products.  

Code of Federal Regulations, 2013 CFR

...Uses for Specific Chemical Substances § 721...epichlorohydrin-polyethylene glycol reaction products. (a) Chemical substance and significant...reporting. (1) The chemical substance identified...epichlorohydrin-polyethylene glycol reaction products...

2013-07-01

452

78 FR 14266 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Notice of Correction to the Final...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Notice of Correction...antidumping duty order on polyethylene terephthalate film, sheet, and strip (PET Film) from Taiwan.\\1\\ The period of review...

2013-03-05

453

Double-concave deformity of the polyethylene tibial post in posterior stabilized total knee arthroplasty.  

PubMed

This report describes a unique case of bilateral total knee arthroplasty necessitating revision of the polyethylene insert, which showed prominent marks on the tibial post resulting from repeated seiza-style sitting. The patient presented 7 years postoperatively with knee pain and flexion disturbance due to continuous joint effusion persisting for more than 4 months. Proliferating synovia throughout the joint revealed reactive synovitis to polyethylene particles. The retrieved polyethylene inserts displayed double-concave deformity of the tibial post with burnishing and creep in tibiofemoral articulation. The damage pattern of retrieved polyethylene inserts reflected the data from tibiofemoral contact location obtained using a shape-matching technique in the early postoperative phase. This case provides an example of damage to the polyethylene tibial post caused by a floor-sitting lifestyle and the potential clinical sequelae. PMID:19261434

Niki, Yasuo; Matsumoto, Hideo; Yoshimine, Fumihiro; Toyama, Yoshiaki; Suda, Yasunori; Banks, Scott A

2009-03-04

454

The effect of entrapped bone particles on the surface morphology and wear of polyethylene.  

PubMed

Clinically retrieved highly cross-linked ultrahigh molecular weight polyethylene (HXPE) acetabular liners have demonstrated scratching, whereas conventional ultrahigh-molecular-weight polyethylene (UHMWPE) implants show a smoother surface early after implantation. In the present study, the potential of bone particles and soft tissues, rather than cement, to scratch the articular surface of HXPE and UHMWPE (gamma radiated) acetabular components was evaluated; multiple bone particles located at the articular surface for 3600 simulated walking cycles replicated the scratches observed on retrieved implants. By remelting, these scratches were confirmed to be due to plastic deformation of the polyethylene, not wear. Furthermore, it was shown using wear testing that these scratches did not affect the subsequent wear rate of HXPE or conventional UHMWPE. Wear rates of scratched conventional and cross-linked polyethylene were not significantly different from unscratched conventional and cross-linked polyethylene, respectively. PMID:18524532

Mimnaugh, Kimberly D; Yao, Jian Q; Laurent, Michel P; Crowninshield, Roy; Mason, James J; Blanchard, Cheryl

2008-06-04

455

Comparison study of morphology and crystallization behavior of polyethylene and poly(ethylene oxide) on single-walled carbon nanotubes.  

PubMed

In this work, we provided a comparison study of morphology and crystallization behavior of polyethylene (PE) and poly(ethylene oxide) (PEO) on single-walled carbon nanotubes (SWNTs) with assistance of supercritical CO(2). The resulting polymer/SWNT nanohybrids were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectra, wide-angle X-ray diffraction, and differential scanning calorimetry. SWNT small bundles were decorated by PE lamellar crystals, forming nanohybrid "shish-kebab" (NHSK) structure, whereas SWNTs were only wrapped by a thin amorphous polymer coating in the case of PEO. The varying morphologies of the nanohybrids were found to depend on the molecular conformation and the interactions between polymer chains and SWNTs. Nonisothermal experiments showed that SWNTs provided heterogeneous nucleation sites for PE crystallization, while the NHSK structure hindered polymer chain diffusion and crystal growth. Also, SWNTs played antinucleation effect on PEO. In addition, the formation mechanism analysis indicated that PE chains preferred to form a homogeneous coating along the tube axis before proceeding to kebab crystal growth. The purpose of this work is to enlarge the area of theoretical understanding of introducing precisely hierarchical structures on carbon nanotubes, which are important for functional design in nanodevice applications. PMID:20593889

Zheng, Xiaoli; Xu, Qun

2010-07-29

456

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

457

Purification of porcine pancreatic lipase by aqueous two-phase systems of polyethylene glycol and potassium phosphate.  

PubMed

An aqueous two-phase system (ATPS) was applied for the purification of porcine pancreatic lipase (PPL) from crude PPL using polyethylene glycol (PEG) and potassium phosphate. Phase diagrams for polyethylene glycol (PEG) and potassium phosphate dibasic were determined at room temperature to find an operating region to first form the ATPS. The PPL was preferentially partitioned into the PEG-rich phase in systems with molecular weights of 1000 and 1500 and concentrated in the phosphate-rich phase in systems with PEG of 4000. Moreover, instead of tie line length (TLL), we used a stability ratio without NaCl in the system, and we first applied fluorescence spectroscopy for the protein conformational analysis of the ATPS. The molecular weight of the purified lipase was determined to be approximately 52 kDa by SDS-PAGE. The enzyme was efficiently purified in PEG 1500/potassium phosphate (17/13, %) at a pH of 7.0 at 4 °C. This system obtained an enzyme partition coefficient of 12.7, an extraction efficiency of 94.7% and a purification factor of approximately 4. These results demonstrate that the aqueous two-phase system is a highly efficient method for PPL purification. PMID:23562905

Zhou, Yu-Jie; Hu, Cheng-Li; Wang, Na; Zhang, Wei-Wei; Yu, Xiao-Qi

2013-03-15

458

[The experimental assessment of high-density ultrahigh molecular weight polyethylene for the prosthetic treatment of auditory ossicles].  

PubMed

The objective of the present study was the comparative assessment of the influence of titanium and high-density ultrahigh molecular weight polyethylene (HDMPE) on the selected biochemical and immunological properties of blood and morphological features of the middle ear tissues in experimental animals. A total of 35 rabbits used were allocated to 3 groups. Groups 1 and 2 included 15 animals each. They were involved in three series of experiments (5 animals per series lasting 15, 60, and 90 days). Group 3 was comprised of 5 animals. Prosthetic treatment of auditory ossicles was performed using implants from modified high-density ultrahigh molecular weight polyethylene (group 1) and titanium implants (group 2). Control animals (group 3) remained intact. There were no significant difference between total bilirubin, AsAT, glucose, creatinine, and total protein levels in blood plasma at different time-points after surgery. HDMPE turned out to have no appreciable effect on immunological characteristics and morphological features of the soft tissues lining tympanic bulla. It is concluded that HDMPE may serve as a material for the fabrication of prostheses of the auditory ossicle chain. PMID:23528461

Khorov, O G; Struk, V A; Novoseletski?, V A

2013-01-01

459

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

460

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, thus affecting the clay dispersion and the final properties of the nanocomposites. In this work, it was proposed to modify the clay with alkyl pyridinium, alkyl imidazolium and alkyl phosphonium intercalating agents, which are more stable than ammonium based cations. Organophilic montmorillonites with enhanced thermal stabilites compared to commercial organoclays (+20°C to +70°C) were prepared. The effect of the chemical structure of the intercalating agent on the capacity of the organoclay to be dispersed in polyethylene matrices was analyzed. In addition, the influence of the dispersion on the thermal stability of the nanocomposites prepared is discussed. In a second part, the effect of the compatibilizing agent characteristics on the quality of the clay dispersion in polyethylene/montmorillonite nanocomposites was analyzed. The mechanical properties and the oxygen permeability of the nanocomposites were evaluated and related to the level of clay delamination and to the strength of the polymer/clay interface, which was evaluated through surface tension measurements.

Stoeffler, Karen

461

A comparison of the adsorption of three adhesive proteins to biomaterial surfaces  

Microsoft Academic Search

The adsorption of three cell adhesive proteins with known thrombogenic activity [fibrinogen (FGN), fibronectin (FN), and vitronectin (VN)] was quantified from mono-component protein solutions, from a quaternary-component protein solution, and from plasma and diluted plasma in order to compare their potential for adsorption to polymeric substrates from solutions of varying complexity. The surfaces studied included polyethylene (PE), silicone rubber (SR),

D. J. Fabrizius-Homan; S. L. Cooper

1992-01-01

462

Insulin Particle Formation in Supersaturated Aqueous Solutions of Poly(Ethylene Glycol)  

PubMed Central

Protein microspheres are of particular utility in the field of drug delivery. A novel, completely aqueous, process of microsphere fabrication has been devised based on controlled phase separation of protein from water-soluble polymers such as polyethylene glycols. The fabrication process results in the formation of spherical microparticles with narrow particle size distributions. Cooling of preheated human insulin-poly(ethylene glycol)-water solutions results in the facile formation of insulin particles. To map out the supersaturation conditions conducive to particle nucleation and growth, we determined the temperature- and concentration-dependent boundaries of an equilibrium liquid-solid phase separation. The kinetics of formation of microspheres were followed by dynamic and continuous-angle static light scattering techniques. The presence of PEG at a pH that was close to the protein's isoelectric point resulted in rapid nucleation and growth. The time elapsed from the moment of creation of a supersaturated solution and the detection of a solid phase in the system (the induction period, tind) ranged from tens to several hundreds of seconds. The dependence of tind on supersaturation could be described within the framework of classical nucleation theory, with the time needed for the formation of a critical nucleus (size <10 nm) being much longer than the time of the onset of particle growth. The growth was limited by cluster diffusion kinetics. The interfacial energies of the insulin particles were determined to be 3.2–3.4 and 2.2 mJ/m2 at equilibrium temperatures of 25 and 37°C, respectively. The insulin particles formed as a result of the process were monodisperse and uniformly spherical, in clear distinction to previously reported processes of microcrystalline insulin particle formation.

Bromberg, Lev; Rashba-Step, Julia; Scott, Terrence

2005-01-01

463

Features of Fluorescence Spectra of Polyethylene Terephthalate Films  

NASA Astrophysics Data System (ADS)

Out of two species of fluorescence of polyethylene terephthalate (PET), intrinsic fluorescence (I), which was caused by short-wavelength (<320 nm) excitation, was dominant for very thin films (less than a few microns), while, trap fluorescence (II), excited at longer wavelengths (>320 nm), was much more intense for thick films. This fact was confirmed, and explained by an elementary formula. Effects of polymerization catalysts onto the fluorescence spectra were found to be indirect; namely, peak positions of the fluorescence were not affected by catalyst systems, while fluorescence intensity was sensitive not only to catalyst systems but also to minute differences in local surroundings. Effects of catalyst systems on the weak absorption bands at 338 nm and 354 nm were examined. Integrated excitation spectra were resolved; therein, a hidden n??* state was found. Most likely, this is related with the weak absorptions at 338 nm and 354 nm, which are the major origins of fluorescence (II).

Ouchi, Isuke; Nakai, Ikuo; Ono, Mitsumasa; Kimura, Shin-ichi

2004-12-01

464

The characterisation of two different degradable polyethylene (PE) sacks  

SciTech Connect

The compostability of two different polyethylene (PE) products on the UK market under open-windrow composting conditions is explored within this paper. Chemical analysis of the PE bags has established their constituents in order to examine how the PE bags have an increased degradability depending on additives. Weight loss of the two different PE products within open-windrow composting conditions was recorded in order to establish the percentage weight loss as an indication of the degradability of the two products and their relative suitability for open-windrow composting. Scanning electron microscopy (SEM) of the PE products over the composting duration established the degradation processes for the PE products within the compost. These analyses concluded that one of the PE product mixes was more degradable than the other. However, neither product completed degraded within the timeframe of 12-14 weeks generally accepted for open-windrow composting in the UK.

Davis, G. [Engineering Management Group, University of Bristol (United Kingdom)]. E-mail: gudavis@cytanet.com.cy

2006-12-15

465

Graphene oxide stabilized polyethylene glycol for heat storage.  

PubMed

Graphene oxide (GO) sheets were introduced to stabilize the melted polyethylene glycol (PEG) during the solid-liquid phase change process, which can be used as a smart heat storage system. The structural properties and phase change behaviors of the PEG-GO composites were comprehensively investigated as a function of the PEG content by means of various characterization techniques. The highest stabilized PEG content is 90 wt% in the composites, resulting in a heat storage capacity of 156.9 J g(-1), 93.9% of the phase change enthalpy of pure PEG. Notably, GO has much stronger impact on lowering of the phase change temperature of PEG compared with some other porous carbon materials (activated carbon and ordered mesoporous carbon) due to the unique thin layer structure of GO. Because of the high heat storage capacity and the moderate phase change temperature, the PEG-GO composite is a promising heat energy storage candidate at mild temperature. PMID:22914763

Wang, Chongyun; Feng, Lili; Yang, Huazhe; Xin, Gongbiao; Li, Wei; Zheng, Jie; Tian, Wenhuai; Li, Xingguo

2012-10-14

466

[Analysis of formaldehyde, acetaldehyde and oligomers in recycled polyethylene terephthalate].  

PubMed

Formaldehyde (FA), acetaldehyde (AA) and oligomers in recycled polyethylene terephthalate (PET) were analyzed by HPLC. All of the physically recycled PET contained detectable levels of FA, AA and oligomers, and the levels were almost the same as in used bottles. Most superclean-like and chemically recycled PET contained lower levels than new pellets. These compounds showed no decrease upon physical recycling, but showed a marked decrease upon superclean-like recycling. In PET sheets made using physically recycled PET, FA was decreased, though AA was increased by the sheeting process as same as new one. FA, AA and oligomers originated from PET resin and their levels in recycled products were almost equivalent to those in new products. It was concluded that there is no particular safety concern about their presence in recycled PET. PMID:16305177

Ohkado, Yuka; Kawamura, Yoko; Mutsuga, Motoh; Tamura, Hiro-omi; Tanamoto, Kenichi

2005-10-01

467

Surface Modification of Polyethylene by Heparin for Improvement of Antithrombogenicity  

NASA Astrophysics Data System (ADS)

The purpose of this paper was to enhance blood compatibility of polyethylene (PE) film. PE film pretreated by argon plasma was subjected to ultraviolet (UV) -induced graft polymerization with Acrylic acid(AAc) (AAc-grafted PE films, PE-g-PAAc) without photo-initiator, then heparin was covalently immobilized on the PE surface (PE-g-HPAAc). The surface properties and microstructure of PE-g-PAAc and PE-g-HPAAc were studied by static contact angle measurement, atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and Attenuated total reflectance Fourier transfer infrared spectroscopy (ATR-FTIR). It was confirmed that AAc and heparin were successfully immobilized onto the surface of PE film. Results of platelet adhesion experiments indicated that the antithrombogenicity of the modified PE film was remarkably improved.

Zhao, Guowei; Chen, Yashao; Dong, Tao; Wang, Xiaoli

2007-04-01

468

Sample length independent conduction current in polyethylene oxide  

NASA Astrophysics Data System (ADS)

The transient current density through ion conducting polyethylene oxide samples of different lengths is measured after application of voltage steps with different amplitudes. In the experiments, it is found that at a given voltage step the long-term current density is independent of the sample length. Qualitatively, the same behavior is attained from computer simulations using a three-dimensional hopping model which takes into account internal ionic charge movements and extrinsic electronic charge injection from the electrodes. It turns out that the width of a depletion zone of mobile ions at the electrode, which only depends on the applied voltage, is responsible for the independence of the current from the sample length.

Martin, Bjoern; Kliem, Herbert

2013-01-01

469

Modeling Low Density Polyethylene with Precisely Placed Butyl Branches  

NASA Astrophysics Data System (ADS)

Polyethylene (PE) is a commodity produced on a massive scale and also is one of the most studied macromolecules. Crystallinity can be controlled by copolymerizing ethylene with ?-olefins, producing a wide range of material responses. Physical properties of PE, obtained via ? olefin copolymerization, depend on the branch content that is directly related to the comonomer incorporation into the PE backbone. Materials with unknown primary structures are produced via chaingrowth chemistry, because unwanted side reactions generate defects in the main backbone that alter the morphological behavior and thermal response. Acyclic diene metathesis (ADMET) polymerization/hydrogenation methodology produce perfect sequenced copolymers of ethylene with ?-olefins. Synthesis and thermal properties of PE with butyl branches precisely placed along the polymer backbone using ADMET chemistry is described within.

Rojas, Giovanni; Wagener, Kenneth B.

470

Space-charge-controlled conductivity in low-density polyethylene  

NASA Astrophysics Data System (ADS)

We studied the dc conductivity of low-density polyethylene in the temperature range from 20 to 90 °C for electric fields from 4 kV m-1 to 20 MV m-1. The isochronal data measured after 1 h are in agreement with the literature. For a long time (6 days), the conduction mechanism is dominated by the space charge trapped in the material. The current does not attain a steady-state value after 29 days at 50 °C and 8 MV m-1. It oscillates continuously, the variations are less regular and the conductivity decreases significantly as the sample thickness increases. The activation energy decreases from 0.8 to 0.58 eV when determined from long time measurements. An explanation is proposed considering the constraints imposed by the trapped space charge on charge injection and transport. We propose to call the observed mechanism space-charge-controlled conductivity.

Neagu, Eugen R.; Marat-Mendes, Jose N.

2003-03-01

471

Dielectric properties of carbon fiber filled low-density polyethylene  

NASA Astrophysics Data System (ADS)

Carbon fiber (CF) filled low-density polyethylene (LDPE) matrix composites was prepared by means of the Hakke driver. The dielectric properties of the CF/LDPE composites as a function of the frequency and the volume fraction of CF were studied. The dielectric constants decrease slowly with increasing the frequency and rise gradually with increasing the CF contents in the composites. As the volume fraction of the CF is up to 0.20, an abrupt increase in the dielectric constant occurs, and accordingly electrical conductivity measured at low frequency increases rapidly at this volume fraction. The percolation theory and the simple concept of polarization in the capacitors are employed to explain these experimental results.

Dang, Zhimin; Shen, Yang; Fan, Lizhen; Cai, Ning; Nan, Cewen; Zhao, Shujin

2003-05-01

472

Thermally-Stimulated Currents in Oxidized Low-Density Polyethylene  

NASA Astrophysics Data System (ADS)

The localized states associated with the C=O groups introduced in low-density polyethylene (LD-PE) by oxidation act as hopping centers above 40°C and enhance the carrier mobility. Oxidation also causes three TSC peaks in LD-PE, designated C1, C2 and C3 in ascending order of temperature. The C1 and C2 peaks are due to depolarization of the C=O dipoles in the ? and ? relaxation regions, respectively. The C3 peak depends strongly upon the electrode materials. Electrons injected from the cathode electrode are possibly trapped in the localized states due to the C=O groups when the specimen is cooled with a polarizing field, and their thermal release causes the C3 peak around 40°C. Above that temperature, these localized states act rather as hopping centers as mentioned above. Partial heating revealed the depth of the localized states to be ca. 1.4 eV.

Mizutani, Teruyoshi; Tsukahara, Toshimichi; Ieda, Masayuki

1980-11-01

473

Deformation of confined poly(ethylene oxide) in multilayer films.  

PubMed

The effect of confinement on the deformation behavior of poly(ethylene oxide) (PEO) was studied using melt processed coextruded poly(ethylene-co-acrylic acid) (EAA) and PEO multilayer films with varying PEO layer thicknesses from 3600 to 25 nm. The deformation mechanism was found to shift as layer thickness was decreased between 510 and 125 nm, from typical axial alignment of the crystalline fraction, as seen in bulk materials, to nonuniform micronecking mechanisms found in solution-grown single crystals. This change was evaluated via tensile testing, wide-angle X-ray diffraction (WAXD), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). With the commercially relevant method of melt coextrusion, we were able to overcome the limitations to the testing of solution-grown single crystals, and the artifacts that occur from their handling, and bridged the gap in knowledge between thick bulk materials and thin single crystals. PMID:22506675

Lai, Chuan-Yar; Hiltner, Anne; Baer, Eric; Korley, LaShanda T J

2012-04-16

474

Gels and foams from ultrahigh molecular weight polyethylene  

SciTech Connect

Ultrahigh molecular weight polyethylene (UHMW PE) foams with densities from 0.04 to 0.2 g/cm{sup 3} have routinely been made in our laboratory. First, an entangled solution of UHMW PE is made. Then, the solution is geled by cooling to crystallize the PE. The gel is later dried to a foam by critical point drying. Viscometry and cloud point measurements were used to determine the gelatin point and the critical gelatin concentrations. Polarized light microscopy and differential scanning calorimetry were used to investigate the effects of cooling rate on the gel, while the effects of cooling rate on the foam were investigated via x-ray diffraction and scanning electron microscopy. We found that rapid cooling of 5 wt % UHMW PE/tetralin solutions to {minus}10{degree}c yielded small, uniform structure at the expense of crystallinity and strength; cooling over three days yielded spherulitic structure with strength. 5 refs., 3 figs.

Hair, L.M.; Letts, S.A.; Tillotson, T.

1988-07-01

475

Thermal conductivity of boron nitride reinforced polyethylene composites  

SciTech Connect

The thermal conductivity of boron nitride (BN) particulates reinforced high density polyethylene (HDPE) composites was investigated under a special dispersion state of BN particles in HDPE, i.e., BN particles surrounding HDPE particles. The effects of BN content, particle size of HDPE and temperature on the thermal conductivity of the composites were discussed. The results indicate that the special dispersion of BN in matrix provides the composites with high thermal conductivity; moreover, the thermal conductivity of composites is higher for the larger size HDPE than for the smaller size one. The thermal conductivity increases with increasing filler content, and significantly deviates the predictions from the theoretic models. It is found also that the combined use of BN particles and alumina short fiber obtains higher thermal conductivity of composites compared to the BN particles used alone.

Zhou Wenying [Department of Applied Chemistry, School of Science, Northwestern Polytechnical University, Xi'an 710072 (China)], E-mail: wyzhou2004@163.com; Qi Shuhua; An Qunli; Zhao Hongzhen; Liu Nailiang [Department of Applied Chemistry, School of Science, Northwestern Polytechnical University, Xi'an 710072 (China)

2007-10-02

476

Immobilization of bacteria in microgel grafted onto macroporous polyethylene  

NASA Astrophysics Data System (ADS)

The development of “Green Chemistry” requires new materials to replace the conventional organic chemistry by biological catalysts, to produce fine chemicals in an environmentally friendly manner. Microbial whole cells can be directly used as biocatalysts, providing a simple and cheap methodology since enzyme isolation and purification are avoided. High-density polyethylene (HDPE) is a very stable polymer though it can be activated by gamma radiation to induce grafting. Glycidyl methacrylate was grafted onto macroporous HDPE and PP in the range of 1-6%, proportional to the initial monomer concentration. Grafted polymers were further chemically modified with ethylenediamine to generate a cationic hydrogel of micron-size thickness onto the internal polymer surfaces. Modified polymers were able to immobilize Gram-positive and Gram-negative bacteria that can catalyze a chemical reaction as efficient as free cells do.

Trelles, J. A.; Quiroga, F.; Britos, C.; Smolko, Eduardo E.; Grasselli, Mariano

2010-03-01

477

WEAR BEHAVIOR OF CARBON NANOTUBE/HIGH DENSITY POLYETHYLENE COMPOSITES  

PubMed Central

Carbon Nanotube/High Density Polyethylene (CNT/HDPE) composites were manufactured and tested to determine their wear behavior. The nanocomposites were made from untreated multi-walled carbon nanotubes and HDPE pellets. Thin films of the precursor materials were created with varying weight percentages of nanotubes (1%, 3%, and 5%), through a process of mixing and extruding. The precursor composites were then molded and machined to create test specimens for mechanical and wear tests. These included small punch testing to compare stiffness, maximum load and work-to-failure and block-on-ring testing to determine wear behavior. Each of the tests was conducted for the different weight percentages of composite as well as pure HDPE as the baseline. The measured mechanical properties and wear resistance of the composite materials increased with increasing nanotube content in the range studied.

Johnson, Brian B.; Novotny, John E.; Advani, Suresh G.

2009-01-01

478

Rheo-optical vibrational spectroscopy of poly(ethylene terephthalate)  

NASA Astrophysics Data System (ADS)

FT-IR spectroscopy is a fast and informative method for the characterization of transient structural changes during deformation and relaxation processes of polymers. These rheo- optical techniques were used to determine changes in orientation, conformation and state of order during elongation, recovery and stress relaxation in poly(ethylene terephthalate) (PET) at various temperatures and sample geometries. Near-infrared (NIR) spectroscopy is more advantageous for applications in industrial process-control, since light-fiber optics can be used and a wider range of film thicknesses can be investigated. Frequently, the NIR region yields less information than the mid-infrared region and it is necessary to calibrate MIR results to NIR spectra by chemometric methods (e.g., partial least squares).

Hoffmann, U.; Okretic, S.; Pfeiffer, Frank; Voelkl, N.; Zahedi Azad, M.; Siesler, H. W.

1994-01-01

479

The Osmotic Potential of Polyethylene Glycol 6000 1  

PubMed Central

Osmotic potential (?s) of aqueous solutions of polyethylene glycol 6000 (PEG-6000) was curvilinearly related to concentration. At given concentrations, ?s increased linearly with temperature. The effects of concentration and temperature on ?s of PEG-6000 solutions differ from those for most salts and sugars and apparently are related to structural changes in the PEG polymer. Measurements of ?s with thermocouple psychrometers are more negative than those with a vapor pressure osmometer, with the psychrometer probably giving the more nearly correct ?s for bulk solutions. An empirical equation permits calculation of ?s from known concentrations of PEG-6000 over a temperature range of 15 to 35 C. Viscometery and gravimetric analysis are convenient methods by which the concentrations of PEG-6000 solutions may be measured.

Michel, Burlyn E.; Kaufmann, Merrill R.

1973-01-01

480

Preparation and characterization of magnetic nanoparticles coated with polyethylene glycol  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles Fe3O4 were prepared in air environment by the coprecipitation method using molar ratios of Fe2+: Fe3+ = 1: 2. The surface of magnetic nanoparticles was coated with sodium oleate as the primary layer and polyethylene glycol 6000 (PEG-6000) as the second layer. The morphology of the particles was investigated by scanning electronic microscopy (SEM). X-ray diffraction (XRD) indicated the sole existence of inverse cubic spinel phase of Fe3O4 and an average size of about 25 nm. Fourier transform infrared spectroscopy (FTIR) analysis indicated existence of two distinct surfactants on the particle surface. In addition, the results of FT-IR indicated that the coated Fe3O4 particles improved the thermal stability due to the interaction between the Fe3O4 particles and protective layers.

Hoa, Le Thi Mai; Thi Dung, Tran; Mau Danh, Tran; Duc, Nguyen Huu; Mau Chien, Dang

2009-09-01

481

Electric Breakdown of Solution-Grown Polyethylene Films without Spherulite  

NASA Astrophysics Data System (ADS)

Self-healing breakdown tests are made at room temperature on solution-grown polyethylene (PE) films without heat treatment. The non heat-treated film has no spherulite and consists of randomly oriented lamellae, in contrast to the heat-treated film consisting of two-dimensional spherulites. The variation of electric strength with voltage rising speed and voltage polarity gives a feature similar to the previous results for the heat-treated films and is again interpreted in terms of roughness of the top surface and space charge formation. The electric strength free from both surface roughness and space charge is higher for the non heat-treated films than for the heat-treated films in which breakdown occurs at spherulite boundaries.

Kitagawa, Keiichi; Sawa, Goro; Ieda, Masayuki

1982-08-01

482

A new route for chitosan immobilization onto polyethylene surface.  

PubMed

Low-density polyethylene (LDPE) belongs to commodity polymer materials applied in biomedical applications due to its favorable mechanical and chemical properties. The main disadvantage of LDPE in biomedical applications is low resistance to bacterial infections. An antibacterial modification of LDPE appears to be a solution to this problem. In this paper, the chitosan and chitosan/pectin multilayer was immobilized via polyacrylic acid (PAA) brushes grafted on the LDPE surface. The grafting was initiated by a low-temperature plasma treatment of the LDPE surface. Surface and adhesive properties of the samples prepared were investigated by surface analysis techniques. An antibacterial effect was confirmed by inhibition zone measurements of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The chitosan treatment of LDPE led to the highest and most clear inhibition zones (35 mm(2) for E. coli and 275 mm(2) for S. aureus). PMID:22944408

Popelka, Anton; Novák, Igor; Lehocký, Marián; Junkar, Ita; Mozeti?, Miran; Kleinová, Angela; Janigová, Ivica; Slouf, Miroslav; Bílek, František; Chodák, Ivan

2012-07-16

483

Microscopic Dynamics of Polyethylene Glycol Chains Interacting with Silica Nanoparticles  

NASA Astrophysics Data System (ADS)

We present high resolution neutron spectroscopic investigations of polyethylene glycol matrices interacti