Search results for "Polyethylene"
showing 10 items of 809 documents
Brush Conformation of Polyethylene Glycol Determines the Stealth Effect of Nanocarriers in the Low Protein Adsorption Regime
2021
For nanocarriers with low protein affinity, we show that the interaction of nanocarriers with cells is mainly affected by the density, the molecular weight, and the conformation of polyethylene glycol (PEG) chains bound to the nanocarrier surface. We achieve a reduction of nonspecific uptake of ovalbumin nanocarriers by dendritic cells using densely packed PEG chains with a "brush" conformation instead of the collapsed "mushroom" conformation. We also control to a minor extent the dysopsonin adsorption by tailoring the conformation of attached PEG on the nanocarriers. The brush conformation of PEG leads to a stealth behavior of the nanocarriers with inhibited uptake by phagocytic cells, whi…
Formation of two-dimensional crystals of icosahedral RNA viruses.
2007
International audience; The formation of 2D arrays of three small icosahedral RNA viruses with known 3D structures (tomato bushy stunt virus, turnip yellow mosaic virus and bromegrass mosaic virus) has been investigated to determine the role of each component of a negative staining solution containing ammonium molybdate and polyethylene glycol. Virion association was monitored by dynamic light scattering (DLS) and virus array formation was visualised by conventional transmission electron microscopy and cryo-electron microscopy after negative staining. The structural properties of viral arrays prepared in vitro were compared to those of microcrystals found in the leaves of infected plants. A…
Evaluation of thin film adhesion to a compliant substrate by the analysis of progressive buckling in the fragmentation test
2009
The interface toughness of a thin coating/compliant substrate system is estimated based on the evolution of coating buckle patterns in the fragmentation test. The linear density of coating buckles as a function of applied strain is determined experimentally for a SiOx coating deposited on a polyethylene terephthalate film. A three-dimensional non-linear finite element model is developed to simulate the process of buckle formation in a single narrow coating strip. The elastic energy released during buckling-driven delamination is obtained from the energy balance in the system before and after the buckling event. Both the interface adhesion and the total energy release rate, which includes th…
Small-angle x-ray scattering experiments for investigating the validity of the two-phase model
1973
A New method for evaluating SAXS curves of polymer samples with lamellar structure is applied to two typical scattering curves measured with a solution-crystallized linear polyethylene and a melt-crystallized branched polyethylene respectively. The method permits a rigorous check of the validity of the two-phase model and yields, without additional measurement, the volume fractions of the two phases and the difference in their densities. The densities can than be obtained by measuring the overall density of the sample. The results are: ρc = 0.996 g/cm3,ρa = 0.854 g/cm3, wa = 0.20 for the solution-crystallized sample; ρc = 0.967 g/cm3,ρa = 0.850 g/cm3, wa = 0.36 for the melt-crystallized sam…
Endothelialization and Anticoagulation Potential of Surface-Modified PET Intended for Vascular Applications.
2018
In vascular tissue engineering, great attention is paid to the immobilization of biomolecules onto synthetic grafts to increase bio- and hemocompatibility-two critical milestones in the field. The surface modification field of poly(ethylene terephthalate) (PET), a well-known vascular-graft material, is matured and oversaturated. Nevertheless, most developed methods are laborious multistep procedures generally accompanied by coating instability or toxicity issues. Herein, a straightforward surface modification procedure is presented engineered to simultaneously promote surface endothelialization and anticoagulation properties via the covalent immobilization of gelatin through a photoactivate…
Practice guidelines for the treatment of hepatitis C: recommendations from an AISF/SIMIT/SIMAST Expert Opinion Meeting.
2010
It is increasingly clear that a tailored therapeutic approach to patients with hepatitis C virus infection is needed. Success rates in difficult to treat and low-responsive hepatitis C virus patients are not completely satisfactory, and there is the need to optimise treatment duration and intensity in patients with the highest likelihood of response. In addition, the management of special patient categories originally excluded from phase III registration trials needs to be critically re-evaluated. This article reports the recommendations for the treatment of hepatitis C virus infection on an individual basis, drafted by experts of three scientific societies.
Effectiveness of telaprevir or boceprevir in treatment-experienced patients with HCV genotype 1 infection and cirrhosis. : Triple therapy in HCV geno…
2014
International audience; BACKGROUND & AIMS: We investigated the effectiveness of the protease inhibitors peginterferon and ribavirin in treatment-experienced patients with hepatitis C virus (HCV) genotype 1 infection and cirrhosis. METHODS: In the Compassionate Use of Protease Inhibitors in Viral C Cirrhosis study, 511 patients with HCV genotype 1 infection and compensated cirrhosis who did not respond to a prior course of peginterferon and ribavirin (44.3% relapsers or patients with viral breakthrough, 44.8% partial responders, and 8.0% null responders) were given either telaprevir (n = 299) or boceprevir (n = 212) for 48 weeks. We assessed percentages of patients with sustained viral respo…
Effect of peginterferon alfa-2a on liver histology in chronic hepatitis C: a meta-analysis of individual patient data
2004
Multicenter randomized trials have shown that once-weekly pegylated interferon (peginterferon) alfa-2a is more efficacious than conventional interferon alfa-2a (IFN) in patients with chronic hepatitis C. We performed a meta-analysis of 1,013 previously untreated patients (from 3 randomized trials) with pretreatment and post-treatment liver biopsies to assess the differences between peginterferon alfa-2a and IFN in terms of their effects on liver histology. Reported values were standardized mean differences (SMD) between patients receiving peginterferon alfa-2a and those receiving IFN (post-treatment value minus baseline value for each group). We used a random-effects model to quantify the a…
Effects of Eradicating Hepatitis C Virus Infection in Patients With Cirrhosis Differ With Stage of Portal Hypertension.
2016
Clearance of hepatitis C virus (HCV) via antiviral treatment changes the course of liver disease. We evaluated the benefit of sustained virologic response (SVR) in patients with HCV and cirrhosis without (stage 1) and with (stage 2) esophageal varices (EV).We performed a prospective cohort study of 444 patients with HCV and compensated cirrhosis (218 with stage 1 and 226 with stage 2 disease) treated with peg-interferon and ribavirin from June 2001 through December 2009 at the University of Palermo, Italy and followed for a median of 7.6 years (range, 1-12.6 years). We used Cox regression analysis to identify variables associated with appearance or progression of EVs, development of hepatoc…
HCV genotype 1 subtypes (1a and 1b): similarities and differences in clinical features and therapeutic outcome.
2015
Aim: To evaluate similarities and differences in HCV-1 subtypes 1a and 1b in the presenting clinical features and the response to peg-interferon and ribavirin (Peg/RIBA).Patients and methods: A total of 1,233 naïve patients with HCV genotype-1 infection, 159 (13 %) with subtype 1a and 1,074 (87 %) with subtype 1b were treated with Peg-IFN/RIBA at 12 Italian centers. Covariates included in the logistic model were age, gender, BMI, serum alanine aminotransferase, serum gamma-glutamiltranspeptidase (γGT), platelets counts, liver fibrosis, the occurrence of type 2 diabetes, baseline viremia, and IL28B genotype.Results: At multivariate analysis, baseline characteristics differentiating patients …