Dielectric behavior of biopolymer based composites containing multi wall carbon nanotubes: Effect of filler content and aspect ratio

Multi wall carbon nanotubes (MWCNTs) with different aspect ratios (30, 105 and 667) were included in a commercial fully biodegradable blend using melt mixing. Samples of composite systems prepared by hot molding and containing up to 1.2 vol% of MWCNTs were studied by means of DC electrical resistivity and dielectric spectroscopy in order to enhance effect of filler content and aspect ratio on their dielectric behavior. Raman spectroscopic investigations and morphological observations were also performed in order to correlate dielectric behavior with surface carbon nanotubes features and to check the actual level of dispersion of carbon nanotubes under the applied processing conditions. Results emphasized that the carbon nanotubes aspect ratio and their surface regularity determine the electrical properties of composites because they strongly influence percolation thresholds, dielectric permittivity and dissipation factor of produced materials. A satisfying dispersion of the filler seems to be achieved under the employed processing conditions. These preliminary results demonstrates possible applications of this type of biobased systems in many applications going from stress control to devices for high storage energy

Non-Alcoholic Fatty Liver Disease: From Pathogenesis to Clinical Impact

Non-Alcoholic Fatty Liver Disease (NAFLD) is caused by the accumulation of fat in over 5% of hepatocytes in the absence of alcohol consumption. NAFLD is considered the hepatic manifestation of metabolic syndrome (MS). Recently, an expert consensus suggested as more appropriate the term MAFLD (metabolic-associated fatty liver disease). Insulin resistance (IR) plays a key role in the development of NAFLD, as it causes an increase in hepatic lipogenesis and an inhibition of adipose tissue lipolysis. Beyond the imbalance of adipokine levels, the increase in the mass of visceral adipose tissue also determines an increase in free fatty acid (FFA) levels. In turn, an excess of FFA is able to determine IR through the inhibition of the post-receptor insulin signal. Adipocytes secrete chemokines, which are able to enroll macrophages inside the adipose tissue, responsible, in turn, for the increased levels of TNF-. The latter, as well as resistin and other pro-inflammatory cytokines such as IL-6, enhances insulin resistance and correlates with endothelial dysfunction and an increased cardiovascular (CV) risk. In this review, the role of diet, intestinal microbiota, genetic and epigenetic factors, low-degree chronic systemic inflammation, mitochondrial dysfunction, and endoplasmic reticulum stress on NAFLD have been addressed. Finally, the clinical impact of NAFLD on cardiovascular and renal outcomes, and its direct link with type 2 diabetes have been discussed

Second GHEP-ISFG exercise for DVI: “DNA-led” victims’ identification in a simulated air crash

The Spanish and Portuguese-Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) has organized a second collaborative exercise on a simulated case of Disaster Victim Identification (DVI), with the participation of eighteen laboratories. The exercise focused on the analysis of a simulated plane crash case of medium-size resulting in 66 victims with varying degrees of fragmentation of the bodies (with commingled remains). As an additional difficulty, this second exercise included 21 related victims belonging to 6 families among the 66 missings to be identified. A total number of 228 post-mortem samples were represented with aSTR and mtDNA profiles, with a proportion of partial aSTR profiles simulating charred remains. To perform the exercise, participants were provided with aSTR and mtDNA data of 51 reference pedigrees —some of which deficient—including 128 donors for identification purposes. The exercise consisted firstly in the comparison of the post-mortem genetic profiles in order to re-associate fragmented remains to the same individual and secondly in the identification of the re-associated remains by comparing aSTR and mtDNA profiles with reference pedigrees using pre-established thresholds to report a positive identification. Regarding the results of the post-mortem samples re-associations, only a small number of discrepancies among participants were detected, all of which were from just a few labs. However, in the identification process by kinship analysis with family references, there were more discrepancies in comparison to the correct results. The identification results of single victims yielded fewer problems than the identification of multiple related victims within the same family groups. Several reasons for the discrepant results were detected: a) the identity/non-identity hypotheses were sometimes wrongly expressed in the likelihood ratio calculations, b) some laboratories failed to use all family references to report the DNA match, c) In families with several related victims, some laboratories firstly identified some victims and then unnecessarily used their genetic information to identify the remaining victims within the family, d) some laboratories did not correctly use “prior odds” values for the Bayesian treatment of the episode for both post-mortem/post-mortem re-associations as well as the ante-mortem/post-mortem comparisons to evaluate the probability of identity. For some of the above reasons, certain laboratories failed to identify some victims. This simulated “DNA-led” identification exercise may help forensic genetic laboratories to gain experience and expertize for DVI or MPI in using genetic data and comparing their own results with the ones in this collaborative exercise.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewe

Membrane lipid and protein adaptations in Antarctic fish

The success of Notothenioids to survive in the Antarctic involves, among other things, adaptive modifications of proteins and membrane lipids, because only the conservation of their biochemical characteristics and physiological state allows physiological processes to proceed at the low temperature of the Antarctic sea. Biological membranes are complex structures whose composition (mainly lipid and protein) and arrangement vary widely both between, and within, cells depending upon function (Gennis, 1989). The phospholipid bilayer holds multiple essential properties for cell membrane function since it: (i) acts as a physical barrier to solute diVusion; (ii) regulates the utilization of energy in transmembrane ion gradients; (iii) mediates the transmembrane movement of specific solutes; (iv) provides an organizing matrix for the assembly of multicomponent metabolic and signal transduction pathways; (v) supplies precursors for the generation of lipid-derived second messengers. Biological membranes may contain different types of proteins related to different cellular functions such as transmembrane transport (channels and carriers), substrate hydrolysis (enzymes), hormone and neurotransmitter recognition (receptors) and protein contributions to the mechanical structure of the membrane. Membrane proteins may be associated with the lipid bilayer in different ways. They have been distinguished as peripheral or integral proteins according to whether they penetrate to a lesser or greater extent into the bilayer and can therefore be isolated by mild or more severe treatments. The amount of lipid in biological membranes ranges between 20 and 80% of the dry weight and, because of the lipids, particular structural and physical properties of the membrane occur

Poly(buthylen terephthalate) based composites containing alumina whiskers: influence of filler functionalization on dielectric properties

In this research PBT-based nanocomposites, including various amounts (up to 10 wt%) of alumina whiskers have been prepared by using a Brabender internal chamber mixer and analysed in terms of dielectric properties