Search results for "stabilizer."

NiII, and ZnII Schiff Base Complexes: Telomeric G-quadruplex Stabilizers

2014

Recently, NiII and ZnII metal complexes of the ligand Salpyrim have been synthesized and characterized. Their affinity for wild-type h-Telo G-quadruplex DNA and for calf thymus DNA was investigated by UV absorption spectroscopy, circular dichroism and viscometry. The data collectively suggest that both complexes bind effectively to G-quadruplexes by direct end-stacking, stabilizing the oligonucleotide secondary structure. The two complexes are also typical B-DNA intercalators. Remarkably, their binding constants, Kb, with the G4s structures are about 10 fold higher than those with B-DNA, highlighting the selectivity. Experiments to evaluate the biological activity of the two complexes again…

Antiepileptic Drugs for the Treatment of Chronic and Episodic Cluster Headache: A Review.

2007

Cluster headache needs to be rapidly diagnosed and effectively managed, as the individual headache attacks that are characteristic of this disorder are excruciatingly painful and debilitating. Preventive therapies are necessary to reduce the frequency of attacks during the cluster period. However, preventive therapy for this disorder is limited by a lack of controlled evidence of efficacy and the potential for systemic toxicity. Recent progress has been made in understanding both the pathophysiological mechanisms underlying cluster headache and the mechanisms of action of the antiepileptic drug class for the treatment of primary headache syndromes. Newly available preliminary clinical trial…

Photo-oxidation behaviour of polyethylene/multi-walled carbon nanotube composite films

2009

Therapeutic use of omega-3 fatty acids in bipolar disorder

2011

Bipolar disorder (BD) is a severe, chronic affective disorder, associated with significant disability, morbidity and premature mortality. Omega-3 polyunsaturated fatty acids (PUFAs) play several important roles in brain development and functioning. Evidence from animal models of dietary omega-3 (n-3) PUFA deficiency suggest that these fatty acids are relevant to promote brain development and to regulate behavioral and neurochemical aspects related to mood disorders, such as stress responses, depression and aggression, as well as dopaminergic content and function. Preclinical and clinical evidence suggests roles for PUFAs in BD. n-3 PUFAs seem to be an effective adjunctive treatment for unip…

Recycling of dry and wet polyamide 6

2002

Recycling of polycondensation polymers can give rise to secondary materials with good mechanical properties only if a careful drying is carried out before the melt reprocessing operations. The presence of humidity provokes the hydrolytic chain scission of the macromolecules and the consequent decrease of molecular weight and properties. In this work, the drying step was substituted by the addition of an antioxidant that is able to protect the macromolecules because it is the autioxidant is more prone to hydrolysis, thus removing the water from the melt. The mechanical properties of polyamide 6 reprocessed more times in wet conditions and in the presence of this stabilizer are even better th…

Natural Anti-oxidants for Bio-polymeric Materials

2017

In this work, three different bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate biobased films for eco-sustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films has been evaluated and compared with that of films additivated with a commercial synthetic light stabilizer. Obtained results show that quercetin molecules are able to slow down the photodegradation rate of all investigated bio-polymeric films, opening new avenues in the formulation of fully renewable polymer-based sy…

Quercetin as natural stabilizing agent for bio-polymer

2014

The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. Th…

Melt stabilization of wet polyamide 6

2002

Abstract Melt processing of polycondensate polymers must be carried out after careful drying in order to avoid any hydrolytic chain scission caused by the presence of water or other small molecules. In this work, the effect of two different antioxidants on the processing and flow properties of a polyamide 6 sample not dried before processing operations has been studied. One of these stabilizers seems to protect the wet polymer from hydrolytic chain scission. This action has been interpreted considering that the stabilizer hydrolyses instead of the polyamide macromolecules.

Natural compounds as light stabilizer for a starch-based biodegradable polymer

2014

Abstract The photooxidation behavior of a commercial starch-based biodegradable polymer, i.e., new generation Mater-Bi, loaded with natural stabilizers was investigated in consideration for outdoor agricultural applications. The photooxidation behavior of the biodegradable films was monitored mainly by mechanical tests and spectroscopic analysis. In order to formulate biodegradable films without any synthetic compounds, suitable for outdoor applications and with good photooxidation stability, antioxidants such as α-tocopherol and quercetin (Q) were considered. The results obtained using natural compounds were compared with those obtained by using a synthetic antioxidant and a light stabiliz…

Photooxidation and Stabilization of Photooxidized Polyethylene and of its Monopolymer Blends

2003

The increasing use of products from recycled polymers, or from blends with recycled polymers exposed to the outdoors, implies the need for good weathering resistance. This is particularly important when the recycled material comes, in turn, from products exposed during their lifetime to the sun. In this case the presence of C=O groups in the macromolecular chains strongly increases the photooxidative degradation kinetics of these secondary materials. In this work the change of the photooxidative degradation of blends of virgin and photooxidized polyethylene was evaluated as a function of the C=O content present in the material. As expected, the presence of the C=O groups strongly increases …