An easy synthetic way to exfoliate and stabilize MWCNTs in a thermoplastic pyrrole-containing matrix assisted by hydrogen bonds

MWCNTs were dispersed in a thermoplastic polymer containing pyrrole units in the main chain and hydroxyl pendant groups, affording a well-distributed percolative network. The resulting soft nanocomposite shows stable conductive behavior.

A forest of SiO2 nanowires covered by a TiO2 thin film for an efficient photocatalytic water treatment

Disordered TiO₂/SiO₂ nanowires possess enhanced photocatalytic activity due to the synergy of morphology and light trapping properties of the NW forest.

Functional characterization of mutant genes associated with autosomal dominant familial hypercholesterolemia: integration and evolution of genetic diagnosis

AIMS

Familial Hypercholesterolemia (FH) is one of the most frequent dyslipidemias, the autosomal dominant form of which is primarily caused by mutations in the LDL receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes, although in around 20% of patients the genetic cause remains unidentified. Genetic testing has notably improved the identification of patients suffering from FH, the most frequent cause of which is the presence of mutations in the LDLR gene. Although more than 1200 different mutations have been identified in this gene, about 80% are recognized to be pathogenic. We aim to overview the current methods used to perform the functional characterization of mutations causing FH and to highlight the conditions requiring a functional characterization of the variant in order to obtain a diagnostic report.

DATA SYNTHESIS

In the current review, we summarize the different types of functional assays - including their advantages and disadvantages - performed to characterize mutations in the LDLR, APOB and PCSK9 genes helping to better define their pathogenic role. We describe the evaluation of splicing alterations and two major procedures for functional characterization: 1. ex vivo methods, using cells from FH patients; 2. in vitro methods using cell lines.

CONCLUSIONS

Functional characterization of the LDLR, APOB and PCSK9 mutant genes associated with FH can be considered a necessary integration of its genetic diagnosis.

General theory of frictional heating with application to rubber friction

The energy dissipation in the contact regions between solids in sliding contact can result in high local temperatures which may strongly effect friction and wear. This is the case for rubber sliding on road surfaces at speeds above 1 mm s(-1). We derive equations which describe the frictional heating for solids with arbitrary thermal properties. The theory is applied to rubber friction on road surfaces and we take into account that the frictional energy is partly produced inside the rubber due to the internal friction of rubber and in a thin (nanometer) interfacial layer at the rubber-road contact region. The heat transfer between the rubber and the road surface is described by a heat transfer coefficient which depends on the sliding speed. Numerical results are presented and compared to experimental data. We find that frictional heating results in a kinetic friction force which depends on the orientation of the sliding block, thus violating one of the two basic Leonardo da Vinci 'laws' of friction.

β-Blockers associated with no class-specific survival benefit in acute intracerebral hemorrhage

OBJECTIVES

Despite the high mortality, there is currently no specific treatment for intracerebral hemorrhage (ICH). Research investigating optimum degree of blood pressure control in patients presenting with ICH and hypertension is ongoing. However, there is limited understanding of the potential benefits of specific classes of antihypertensive therapy. β-Adrenergic antagonists may provide neuroprotection from inflammation-induced injury by inhibiting sympathetic nervous system mediated immune activation. We examined mortality in ICH patients receiving β-adrenergic antagonists to determine whether this class of antihypertensive therapy was associated with improved survival.

METHODS

A retrospective analysis of a large, prospectively collected database of patients presenting with acute ICH was performed. Patients were grouped by inpatient β-blocker treatment to determine an effect on mortality during the inpatient stay and at 3 months of follow-up. Additional analysis was conducted comparing β-blocker therapy to any other antihypertensive treatment to determine a class-specific association of β-blocker treatment with mortality.

RESULTS

The study population included 426 patients with acute, spontaneous ICH. Inpatient β-blocker use was independently associated with decreased rates of inpatient death and mortality at 3 months of follow-up. However, univariate and multivariable analyses comparing β-blocker use to other antihypertensives failed to show any class-specific reduction in mortality at either time point.

DISCUSSION

Our study demonstrates that the improvement seen in patients treated with β-adrenergic antagonists is not an effect unique to this class. This supports ongoing trials to determine optimum levels of blood pressure control using multiple classes of antihypertensives.

Rubber friction for tire tread compound on road surfaces

We have measured the surface topography and calculated the surface roughness power spectrum for an asphalt road surface. For the same surface we have measured the friction for a tire tread compound for velocities 10(-6) m s(-1) < v < 10(-3) m s(-1) at three different temperatures (at -8 °C, 20 °C and 48 °C). The friction data was shifted using the bulk viscoelasticity shift factor a(T) to form a master curve. We have measured the effective rubber viscoelastic modulus at large strain and calculated the rubber friction coefficient (and contact area) during stationary sliding and compared it to the measured friction coefficient. We find that for the low velocities and for the relatively smooth road surface we consider, the contribution to friction from the area of real contact is very important, and we interpret this contribution as being due to shearing of a very thin confined rubber smear film.

Fine-tuning of substrate architecture and surface chemistry promotes muscle tissue development

Tissue engineering has been increasingly brought to the scientific spotlight in response to the tremendous demand for regeneration, restoration or substitution of skeletal or cardiac muscle after traumatic injury, tumour ablation or myocardial infarction. In vitro generation of a highly organized and contractile muscle tissue, however, crucially depends on an appropriate design of the cell culture substrate. The present work evaluated the impact of substrate properties, in particular morphology, chemical surface composition and mechanical properties, on muscle cell fate. To this end, aligned and randomly oriented micron (3.3±0.8 μm) or nano (237±98 nm) scaled fibrous poly(ε-caprolactone) non-wovens were processed by electrospinning. A nanometer-thick oxygen functional hydrocarbon coating was deposited by a radio frequency plasma process. C2C12 muscle cells were grown on pure and as-functionalized substrates and analysed for viability, proliferation, spatial orientation, differentiation and contractility. Cell orientation has been shown to depend strongly on substrate architecture, being most pronounced on micron-scaled parallel-oriented fibres. Oxygen functional hydrocarbons, representing stable, non-immunogenic surface groups, were identified as strong triggers for myotube differentiation. Accordingly, the highest myotube density (28±15% of total substrate area), sarcomeric striation and contractility were found on plasma-coated substrates. The current study highlights the manifold material characteristics to be addressed during the substrate design process and provides insight into processes to improve bio-interfaces.

Photovoltaic response of carbon nanotube-silicon heterojunctions: effect of nanotube film thickness and number of walls

We report on the multiwall carbon nanotube application as energy conversion material to fabricate thin film solar cells, with nanotubes acting as photogeneration sites as well as charge separators, collectors and carrier transporters. The device consists of a semitransparent thin film of nanotubes coating a n-type crystalline silicon substrate. Under illumination electron-hole (e-h) pairs, generated in the nanotubes and in the silicon substrate underneath, are split and charges are transported through the nanotubes (electrons) and the n-Si (holes). We found that a suitable thickness of the nanotube thin film, high density of Schottky junctions between nanotubes and n-Si and lowest number of nanotube walls are all fundamental parameters to improve the device incident photon to electron conversion efficiency. Multiwall carbon nanotubes have been synthesized by chemical vapour deposition in an ultra high vacuum chamber by evaporating a given amount of iron at room temperature and then exposing the substrate kept at 800 degrees C at acetylene gas. The amount of deposited iron is found to directly affect the nanotube size distribution (inner and outer diameter) and therefore the number of walls of the nanotubes.

Source of cell injected is a critical factors for short and long engraftment in xeno-transplantation

This study aims to investigate engraftment of human cord blood and foetal bone marrow stem cells after in utero transplantation via the intracoelomic route in the sheep. Here, we performed transplantation in 14 single and 1 twin sheep foetuses at 40-47 days of development, using a novel schedule for injection. (i) Single injection of CD34(+) human cord blood stem cells via the coelomic route (from 10 to 50 x 10(4)) in seven single foetuses. (ii) Single injection of CD34(+) foetal bone marrow stem cells via the intracoelomic route with further numbers of cells (20 x 10(5) and 8 x 10(5), respectively) in three single and in one twin foetuses. (iii) Double fractioned injection (20-30 x 10(6)) via the coelomic route and 20 x 10(6) postnatally, intravenously, shortly after birth of CD3-depleted cord blood stem cells in four single foetuses. In the first group, three single foetuses showed human/sheep chimaerism at 1, 8 and 14 months after birth. In the second group, the twin foetuses showed human/sheep chimaerism at 1 month after birth. In the third group, only two out of four single foetuses that underwent transplantation showed chimaerism at 1 month. While foetal bone marrow stem cells showed good short-term engraftment (1 month after birth), cord blood stem cells were able to persist longer in the ovine recipients (at 1, 8 and 14 months after birth).

Macro-creatine kinase and macro-lactate dehydrogenase in a girl with ulcerative colitis

We report the case of a girl affected by ulcerative colitis with high serum levels of creatine kinase and lactate dehydrogenase due to the presence of macroenzymes. Our observation suggests that the knowledge of this association may be helpful when evaluating ulcerative colitis patients with unexplained isolated elevation of one or more serum enzyme activities.

Rapid detection of mycoplasma in continuous cell lines using a selective biochemical test

Mycoplasma contamination is a deleterious event for a cell culture laboratory due to the ability of this microorganism to contaminate cell culture leading up to the production of false data or, in the worst cases, to the loss of cell culture itself. Fortunately, mycoplasma can be eradicated by the use of antibiotics, but early detection of contamination is peremptory. Here, we propose the use of a sensitive and specific biochemical test named MycoAlert. In particular, as regards cell cultures not yet treated with antibiotics, sensitivity, specificity, positive and negative predictive values of MycoAlert assay gave excellent scores of 100%, 97%, 89% and 100%, respectively.

RAS and MTHFR Gene Polymorphisms in a Healthy Exercise-trained Population: Association with the MTHFR (TT) Genotype and a Lower Hemoglobin Level

The aim of this study was to determine the frequencies of ACE (I/D), AGT (M235T), AT1R (A1166C) and MTHFR (C677T) polymorphisms in a well-defined (in regards to health and nutritional status and lifestyle) population of young, healthy, exercise-trained subjects (no. 100) from the Campania region of Southern Italy. We also investigated whether there was any correlation between these polymorphisms and biochemical, hematological and hemostatic parameters in this "low-risk" population. Gene polymorphisms were analyzed with the polymerase chain reaction and restriction enzyme analysis. Allele frequencies of the genotypes examined were in Hardy-Weinberg equilibrium and agree with those reported in the Italian population. No associations were found between ACE, AGT, AT1R gene polymorphisms and anthropometric, clinical and laboratory parameters. However, the MTHFR (C677T) polymorphism was significantly associated with lower hemoglobin plasma levels in TT vs. CC + CT females (p < 0.016). This report is the first to describe the frequencies of RAS and MTHFR gene polymorphisms in young, exercise-trained volunteers from Campania and to identify an association between the MTHFR gene polymorphisms and lower hemoglobin plasma levels in young healthy females.