Search results for "polypropylene"
showing 10 items of 177 documents
Cytokine modifications after tension-free hernioplasty or open conventional inguinal hernia repair
2001
Abstract Background: The purpose of this study was to evaluate the involvement of proinflammatory cytokines (interferon-γ [INF-γ], interleukin [IL]-6) and anti-inflammatory cytokines (IL-4, IL-l0, IL-13) in patients undergoing Lichtenstein tension-free hernioplasty (LH) using polypropylene prosthetic materials or conventional Bassini hernia (BH) repair. Methods: Thirty-five male patients (age range 25 to 60 years) with unilateral inguinal hernia without complications or recurrence were included in this study. Randomly, patients underwent conventional operation and had their inguinal hernia repair performed with polypropylene mesh. Peripheral venous blood samples were collected 24 hours prio…
Tension-free hernia repair is associated with an increase in inflammatory response markers against the mesh.
2000
Abstract Background: The purpose of this study was to evaluate the involvement of inflammatory mediators in patients undergoing Lichtenstein tension-free hernioplasty (LH) using polypropylene prosthetic materials or conventional Bassini hernia repair (BH). Methods: Thirty patients male with unilateral inguinal hernia without complications or recurrence were included in this study. Randomly, patients underwent LH or BH. Peripheral venous bloods samples were collected 24 hours prior to surgery and then 6, 24, 48 and 168 hours postoperatively. Results: We present evidences that LH patients showed a higher increased serum level of fibrinogen, C-reactive protein, alpha-1-antitrypsin, and interle…
Modifications in the production of cytokines and growth factors in drainage fluids following mesh implantation after incisional hernia repair
2005
Abstract Background The aim of this study was to evaluate changes in the production of some cytokines (interleukins [ILs]-6, -10, -1, and -1ra), vascular endothelial growth factor, and beta-fibroblast growth factor after polypropylene mesh implantation. Methods Twenty female patients were divided into 2 groups. In 1 group, hernia repair was performed with conventional sutures (CR), whereas in the other group polypropylene mesh (MR) was used. Growth factors and cytokines production was analyzed in wound drain fluids based on the amount produced during 24 hours. Results IL-1 increased substantially in MR patients on postoperative days 1 and 2. IL1-ra and IL-10 production was always significan…
Treatment of isolated ascending aortic aneurysm by off-pump epiaortic wrapping is safe and durable.
2016
OBJECTIVES: Isolated ascending aortic aneurysm (iAA) is usually treated by open graft repair requiring sternotomy, cardiopulmonary bypass (CPB) and cardioplegia. This approach carries significant mortality in older patients or those presenting with comorbidities. We report an original series of patients presenting with iAA and treated with epiaortic wrapping by using a synthetic mesh. This less invasive aortic repair technique allows reducing the aortic diameter to a predefined value and is performed without CPB. METHODS: Data from patients presenting with an iAA and treated with the wrapping technique (WT) by polypropylene/polyester mesh from November 2006 to July 2015 were collected. The …
Quantification of poisons for Ziegler Natta catalysts and effects on the production of polypropylene by gas chromatographic with simultaneous detecti…
2020
[EN] This article describes a new simultaneous method for the analysis of sulfur-type poisons, hydrocarbons and permanent gases affecting the productivity of the Ziegler Natta catalyst during the synthesis of polypropylene on an industrial scale in a fluidized-bed reactor. The identification was achieved employing a configuration of the seven-valve chromatographic system, with events at different times, allowing distribution of the sample through multiple columns, and finally reaching the helium ionization detectors of pulsed discharge, flame ionization and mass spectrometry. The results obtained show a good precision of the method used because the variability was less than 1.02% in area an…
THERMOMECHANICAL DEGRADATION OF A POLYPROPYLENE/GRAPHENE NANOCOMPOSITE
2016
In this work the morphology and the rheological and mechanical properties of a nanocomposite made of a polypropylene with graphene nanoplatelets (GNP) have been investigated as a function of the compounding parameters to evaluate the thermomechanical degradation behaviour of this system. The presence of graphene seems to reduce the thermomechanical degradation of the matrix. A better dispersion of the GNP seems the cause of this behaviour.
Isolation of fibroblasts for coating of meshes for reconstructive surgery: differences between mesh types.
2009
Aims: An extensive colonization of surgical meshes with autologous fibroblasts may reduce complications. Therefore, we aimed to establish a technique that allows isolation and propagation of fibroblasts from vaginal biopsies. Using these cells we tested the applicability of several clinically applied meshes for fibroblast coating. Materials & methods: Fibroblasts were isolated from vaginal tissue after digestion with collagenase. Characterization was performed by immunostaining for cytokeratin 5, 6 and 14, smooth muscle actin and vimentin. A semiquantitative technique was applied to determine the degree of mesh coating 5 h and 5 weeks after seeding of fibroblasts. Seven meshes of diffe…
Residual antibacterial activity of a new modified sodium hypochlorite-based endodontic irrigation solution
2010
Objective: In this in vitro study the antibacterial substantivity of a new sodium hypochlorite-based root canal irrigant (Hypoclean) in bovine root dentin was investigated. Study Design: Ninety dentin tubes prepared from bovine incisor teeth were used. After contamination for 14 days with Enterococcus faecalis, the specimens were divided into five groups as follows: Hypoclean; Tetraclean; 5.25% sodium hypochlorite (NaOCl); infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected with round burs into tryptic soy broth and after culturing, the number of colony-forming units (CFU) was counted. Results: The number of CFU was minimum in t…
Polypropylene and poly(ethylene-co-1-octene) effective synthesis with diamine-bis(phenolate) complexes: Effect of complex structure on catalyst activ…
2017
A series of group 4 metal complexes bearing amine-bis(phenolate) ligands with the amino side-arm donor: (μ-O)[Me2N(CH2)2N(CH2-2-O-3,5-tBu2-C6H2)2ZrCl]2 (1a), R2N(CH2)2N(CH2-2-O-3-R1-5-R2-C6H2)2TiCl2 (R = Me, R1, R2 = tBu (2a), R = iPr, R1, R2 = tBu (2b), R = iPr, R1 = tBu, R2 = OMe (2c)), and Me2N(CH2)2N(CH2-2-O-3,5-tBu2-C6H2)(CH2-2-O-C6H4)TiCl2 (2d) are used in ethylene and propylene homopolymerization, and ethylene/1-octene copolymerization. All complexes, upon their activation with Al(iBu)3/Ph3CB(C6F5)4, exhibit reasonable catalytic activity for ethylene homo- and copolymerization giving linear polyethylene with high to ultra-high molecular weight (600·× 103–3600·× 103 g/mol). The activi…
Processing and mechanical properties of organic filer-polypropylene composites
2005
The addition of organic fillers into thermoplastic polymers is an interesting issue, which has had growing consideration and experimentation during the last years. It can give rise to several advantages. First, the cost of these fillers is usually very low. Also, the organic fillers are biodegradable (thus contributing to an improved environmental impact), and finally, some mechanical and thermomechanical properties can be enhanced. In this study, the effect of the addition of different organic fillers on the mechanical properties and processability of an extrusion-grade polypropylene were investigated. The organic fillers came from natural sources (wood, kenaf, and sago) and were compared …