Search results for "High-density"
showing 10 items of 139 documents
On the compatibilization of PET/HDPE blends through a new class of copolyesters
2000
Polyethyleneterephthalate (PET) and polyethylene are incompatible polymers and their blends show, in general, poor properties. Compatibilization is then a necessary step to obtain blends with good mechanical and barrier properties. In this work different compatibilizing agents were used, i.e. a maleic anhydride elastomer and some new products containing graft-copolymers having polyester segments grafted onto polyethylene backbone chains. Both the functionalized elastomer and the new products drastically improve the morphology and the ductility of the blend. In the case of the modified elastomer the compatibilizing action has been attributed to the formation of H-bonds whereas the copolymers…
Rheological behaviour, filmability and mechanical properties of biodegradable polymer films
2014
The rheological properties in shear flow and non isothermal elongational flow of two biodegradable polymers, belonging to two different classes of materials, have been measured and compared with those of a film blowing grade high density polyethylene in order to assess the filmability of these polymers. The mechanical properties of isotropic and anisotropic samples have been also reported.
Small angle scattering study of the structure of isotactic polypropylene-hydrogenated oligo(cyclopentadiene) blends
1996
Abstract Blends of isotactic polypropylene ( i PP) and hydrogenated oligo cyclopentadiene (HOCP) have been studied by means of small angle X-ray scattering in the temperature range 70–160°C. The structure of blends containing less than 25% HOCP is very similar to the one of plain i PP, i.e. lamellae whose thickness increases by increasing the temperature. Blends containing more than 25% HOCP are characterized by two kinds of lamellae formed by layers of i PP and amorphous material rich in i PP and in HOCP, respectively. The crystallizable i PP present in both phases crystallizes from the melt, in analogy to what happens in HDPE/HOCP blends and in agreement with the values of the crystallini…
Research of the physical-chemical properties of adhesive radiation-modified thermosetting materials based on polyolefins and their composites
1999
The present paper surveys the investigation results of the adhesive behavior with steel of different polyethylenes (LDPE, HDPE) irradiated with γ-radiation in vacuum, oxygen, and air, using rheological, optical, thermomechanical and other methods. To study the adhesive contact, the technological parameters applicable to thermosetting polymer material were taken into consideration. The results show the suitable methods in order to obtain thermosetting polymer materials with improved adhesive and thermomechanical properties.
Cardiovascular diseases and HCV infection: a simple association or more?
2013
HCV infection, metabolic disorders and cardiovascular alterations, considered alone or in combination, are common conditions in a large proportion of the general population. Consequently, determining whether the association of HCV infection with cardiometabolic disorders is simply coincidental or, conversely, caused by pathogenetic mechanisms (in)directly linking chronic HCV infection to these disorders, would be of extreme relevance. Several clinical studies have shown that metabolic disorders—namely, type 2 diabetes,1 insulin resistance (IR)2 and hepatic steatosis3—are highly prevalent in patients with chronic hepatitis C (CHC) compared with non-infected patients. Experimental and clinica…
Closed-Loop Acoustic Stimulation During Sleep in Children With Epilepsy: A Hypothesis-Driven Novel Approach to Interact With Spike-Wave Activity and …
2019
Slow waves, the electroencephalographic (EEG) hallmark of deep sleep, can be systematically manipulated by acoustic stimulation: stimulation time-locked to the down phase of slow waves reduces, whereas stimulation time-locked to the up phase increases slow waves. Spike-waves during sleep seem to be related to slow waves, raising the question of whether spike-waves can be systematically influenced by such acoustic stimulation. In five pediatric patients, all-night EEG was recorded, combined with real-time slow wave detection. Throughout the night, acoustic stimulation was performed in a 3 × 5-min-block design (no stimulation—stimulation—no stimulation). Tones were applied time-locked either …
Separating the Mechanism-Based and Off-Target Actions of Cholesteryl Ester Transfer Protein Inhibitors With CETP Gene Polymorphisms
2010
Background— Cholesteryl ester transfer protein (CETP) inhibitors raise high-density lipoprotein (HDL) cholesterol, but torcetrapib, the first-in-class inhibitor tested in a large outcome trial, caused an unexpected blood pressure elevation and increased cardiovascular events. Whether the hypertensive effect resulted from CETP inhibition or an off-target action of torcetrapib has been debated. We hypothesized that common single-nucleotide polymorphisms in the CETP gene could help distinguish mechanism-based from off-target actions of CETP inhibitors to inform on the validity of CETP as a therapeutic target. Methods and Results— We compared the effect of CETP single-nucleotide polymorphisms …
Dysfunctional High-Density Lipoproteins Are Associated With a Greater Incidence of Acute Coronary Syndrome in a Population at High Cardiovascular Risk
2020
Background: Studies have failed to establish a clear link between high-density lipoprotein (HDL) cholesterol and cardiovascular disease, leading to the hypothesis that the atheroprotective role of HDL lies in its biological activity rather than in its cholesterol content. However, to date, the association between HDL functional characteristics and acute coronary syndrome has not been investigated comprehensively. Methods: We conducted a case-control study nested within the PREDIMED (Prevención con Dieta Mediterránea) cohort, originally a randomized trial in which participants followed a Mediterranean or low-fat diet. Incident acute coronary syndrome cases (N=167) were individually matched …
A2.2 Uveitis is not associated with cardiovascular disease risk factors in patients with ankylosing spondylitis
2014
Background and Objectives Ankylosing spondylitis (AS) is a chronic, autoimmune, systemic, inflammatory disease. Recently, a link has been established between autoimmune inflammatory diseases, incl. AS, and the risk of developing cardiovascular disease (CVD). Uveitis is the most frequent extraarticular location of AS - it occurs in about 25 - 40% of patients. The impact of evidence of uveitis during the course of AS still remains a challenge. Does AS with uveitis differ from AS without uveitis? The objective of this study was to detect the link between uveitis during the course of AS and the CVD risk factors in patients with AS. Materials and Methods 77 AS patients classified using the modif…
Combined Dyslipidemia: Should the Focus be LDL Cholesterol or Atherogenic Dyslipidemia?
2012
As the population becomes more obese and the prevalence of diabetes and the metabolic syndrome increases, low-density lipoprotein-cholesterol (LDL-C) may lose its value as a sole predictor for cardiovascular risk among lipids. Combined dyslipidemia is typically characterized by elevations in LDL-C and triglyceride levels, often accompanied by decreased high-density lipoproteincholesterol (HDL-C) concentrations and increased levels of small, dense LDL. This common disorder results from overproduction of hepatically synthesized apolipoprotein B in very low-density lipoproteins. In the last few years most of the international scientific guidelines as well as several expert panels have confirme…