Search results for "Polyethylenes"

New aspects in the histological examination of polyethylene wear particles in failed total joint replacements.

2002

The most important long-term complication in total joint replacements is aseptic osteolysis. Wear particles such as polyethylene (PE) debris are considered to be one of the causes that play a central role. Several studies indicated that PE can be visualised in paraffin-embedded tissue sections not only by polarised light, but also after oil red staining. To determine whether oil red staining enables sensitive detection of PE, we examined staining of mechanically-produced PE particles by oil red. Furthermore, we studied oil red staining of paraffin-embedded tissue specimens of patients with failed uncemented and cemented total knee and hip prostheses. We applied double labelling of sections …

Cyclodextrin and Adamantane Host-Guest Interactions of Modified Hyperbranched Poly(ethylene imine) as Mimetics for Biological Membranes

2011

Low-density polyethylene/polyamide/clay blend nanocomposites: Effect of morphology of clay on their photooxidation resistance

2017

The photooxidation behaviour of low-density polyethylene (LDPE)/polyamide (PA) blends, containing polyamide 11 (PA11) or polyamide 6 (PA6), has been investigated in the absence and presence of a small amount of commercial organomodified clay (OMMT). The polymer blends LDPE/PA11 and LDPE/PA6 at 75/25 wt./wt.%, with and without OMMT, have been prepared by a two-step procedure: extrusion and sheet formulation. The formulated complex systems have been subjected to accurate morphological analysis in order to evaluate the effect of the OMMT presence on the refinement of the blend morphology. Furthermore, the produced sheets have been subjected to arterial UVB exposure and the variations of the me…

Effect of temperature on the release of carvacrol and cinnamaldehyde incorporated into polymeric systems to control growth and biofilms ofEscherichia…

2015

This study assessed the effect of temperature on the release of essential oil components incorporated by melt compounding into polymeric films. Specifically, polyethylene-co-vinylacetate (EVA) films containing carvacrol (CAR) and cinnamaldehyde (ALD), alone and in combination, were prepared and their surface and mechanical properties and antibacterial and anti-biofilm activity against Escherichia coli and Staphylococcus aureus were evaluated. The addition of ALD and CAR did not provoke variation in the surface morphology of EVA and allowed their delivery. At 37°C, films containing CAR, ALD or their combination (25+75%) were found to have the strongest bactericidal effect, whereas at lower t…

Synthesis, structural studies and reactivity of vanadium complexes with tridentate (OSO) ligand

2007

The direct reaction between [VCl3(thf)3] or [VO(OEt)3] and 2,2′-thiobis{4-(1,1,3,3-tetramethyl-butyl)phenol (tbopH2) leads to the formation of [V2(µ-tbop-κ3O,S,O)2Cl2(CH3CN)2] (1)·4CH3CN or [V2(µ-OEt)2(O)2(tbop-κ3O,S,O)2] (2), respectively, in high yield. Compounds 1 and 2 were characterized by chemical and physical techniques including X-ray crystallography and variable temperature magnetic susceptibility studies (J = −29.1 cm−1) for 1. Complexes 1 and 2 were supported on MgCl2 and when activated with aluminium alkyls, were found to effectively polymerize ethene to produce polyethylene with a narrow molecular weight distribution Mw/Mn ∼ 3.

Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets

2001

In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet contai…

Interactions between aroma and edible films. 1. Permeability Of methylcellulose and low-density polyethylene films to methyl ketones.

1998

This work contributes to the study of aroma transfers through edible and plastic packaging films. Permeability, sorption, and diffusivity of three methyl ketones (2-heptanone, 2-octanone, and 2-nonanone) in and through low-density polyethylene and methylcellulose-based edible films have been determined. Permeability was measured using a dynamic method coupled with a gas chromatograph. The methyl ketone permeability of polyethylene films mainly depends on diffusivity of the penetrant in the polymer. In the case of 2-heptanone, a saturation of the polymer network is observed at high vapor concentrations. The formation of clusters could take place when concentrations are higher in the vapor ph…

Analysis of odour and taste problems in high-density polyethene

1998

Abstract The compounds that cause off-flavours in plastics, have been recognized mainly as carbonyl compounds (aldehydes, ketones and esters). They occur in low concentrations, and due to their low-threshold odour concentrations, their typical odours were identified. Most of these off-flavour compounds are volatile. Chemical analysis of smelling compounds requires a very sensitive method with a high-resolution capability. The analysis of volatile organic compounds (VOCs) in high density polyethene (HD-PE) granules and waters in which the granules have been shaken for 4 h, were carried out by gas chromatography–mass spectrometry–sniffing system (GC–MS–SNIFF) and by gas chromatography–fourier…

Percutaneous transrenal catheter retrieval.

1984

Percutaneous transrenal catheter retrieval was successfully performed in 6 of 7 patients using the percutaneous transrenal access. Three broken nephrostomy tubes and 3 indwelling splints were extracted. The instruments used were deflecting guide wire in 1, grasping forceps in 2, and Dormia stone basket in 3 instances. No complications were encountered.

Inorganic Mercury Sequestration by a Poly(ethylene imine) Dendrimer in Aqueous Solution

2015

The interaction of the G-2 poly(ethylene imine) dendrimer L, derived from ammonia as initiating core, with Hg(II) and HgCl4 2− was studied in aqueous solution by means of potentiometric (pH-metric) measurements. Speciation of these complex systems showed that L is able to form a wide variety of complexes including 1:1, 2:1, 3:1 and 3:2 metal-to-ligand species, of different protonation states, as well as the anion complexes ((H7L)HgCl4) 5+ and ((H8L)HgCl4) 6+ . The stability of the metal complexes is very high, making L an excellent sequestering agent for Hg(II), over a large pH range, and a promising ligand for the preparation of functionalized activated carbons to be employed in the remedi…