Influence of CYP1A2 and NAT2 Metabolic Phenotypes on Smokers' Urinary Mutagenicity

The influence of the metabolic phenotypes NAT2 and CYP1A2 on urinary mutagenicity of 118 smokers was studied. Mutagenicity of urine samples was determined by Ames test (preincubation plate incorporation assay on YG1024 Salmonella typhimurium strain with S9 mix). Urinary nicotine plus its metabolites were determined to check cigarette smoke intake. The N -acetyltransferase (NAT2) and cytochrome P450 1A2 (CYP1A2) phenotypes were measured by the molar ratio of urinary caffeine metabolites, determined by HPLC analysis. Urinary mutagenicity was significantly higher in smokers CYP1A2 extensive (EM) than in CYP1A2 poor metabolizers (PM) (Mann-Whitney U test, p = 0.020). Linear multiple regression analysis shows that an increase in urinary mutagenicity levels was significantly related to cigarette smoke intake and to CYP1A2 N -hydroxylation activity ( t = 5.06, p < 0.001, and t = 2.33, p = 0.021), but not to NAT2 acetylation phenotype. In conclusion, phenotypic differences in metabolic activation of tobacco smoke mutagens are able to modulate the presence of mutagens in urine of cigarette smokers and, consequently, the potential genotoxic risk.     

Secondary sulphate aerosols and cirrus clouds detection with SEVIRI during Nabro volcano eruption

Secondary sulphate aerosols (SSAs) and cirrus clouds in the upper troposphere–lower stratosphere (UTLS) are two key atmospheric constituents that can modulate the Earth’s radiative balance. In this article, we present a new preliminary detection algorithm for UTLS SSAs with the Spinning Enhanced Visible and Infrared Imager (SEVIRI) geostationary instrument. This algorithm is used in combination with a well-established existing clouds classification algorithm, to provide, in perspective, a combined tool to better characterize the aerosol–cirrus interactions at the regional scale and at very high temporal resolution, thus potentially contributing to the understanding of the SSAs’ direct–indirect impact on the Earth’s radiative balance. This new combined tool is tested on the Nabro volcano eruption of June–July 2011, which is known to have emitted a great amount of SSA gaseous precursors in the UTLS and to have interacted with the peculiar Asian monsoon dynamics during summer 2011. Although volcanic aerosol–cirrus interactions are not analysed in details at this stage, this work demonstrates that this can be carried out with SEVIRI by introducing a new dedicated SSA product. First results of the new SSA detection algorithm are encouraging towards the use of this combined product.     

Volatile emerging contaminants in melon fruits,analysed by HS-SPME-GC-MS

The aim of this research was to develop and validate a headspace-solid phase micro-extraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) method for the determination of volatile emerging contaminants in fruit. The method showed good precision (RSD ≤ 14%) and satisfactory recoveries (99.1–101.7%) and LOD and LOQ values ranging between 0.011–0.033 μg kg^?1 and 0.037–0.098 μg kg^?1, respectively. The method was applied to investigate the content of volatile emerging contaminants in two varieties of melon fruit (Cucumis melo L.) cultivated adjoining high-risk areas. Glycol ethers, BHT, BHA and BTEX (benzene, toluene, ethylbenzene and xylene) were determined in melon fruit pulps for the first time, with different sensitivities depending on sample and variety. Although the amount of the volatile contaminants in the melon samples were in the order of µg kg^?1, the safety of vegetable crops cultivated near risk areas should be more widely considered. The results showed that this accurate and reproducible method can be useful for routine safety control of fruits and vegetables.     

Source Reconstruction of Atmospheric Releases with Limited Meteorological Observations Using Genetic Algorithms

A genetic algorithm is paired with a Lagrangian puff atmospheric model to reconstruct the source characteristics of an atmospheric release. Observed meteorological and ground concentration measurements from the real-world Dipole Pride controlled release experiment are used to test the methodology. A sensitivity study is performed to quantify the relative contribution of the number and location of sensor measurements by progressively removing them. Additionally, the importance of the meteorological measurements is tested by progressively removing surface observations and vertical profiles. It is shown that the source term reconstruction can occur also with limited meteorological observations. The proposed general methodology can be applied to reconstruct the characteristics of an unknown atmospheric release given limited ground and meteorological observations.     

Evidence for electro-chemical interactions between multi-walled carbon nanotubes and human macrophages

Carbon multi-walled nanotubes (MWCNTs) may have several dangerous effects on different cell systems, but the mechanisms responsible for their cytotoxicity are not well known yet. At present, very little is known about the electrical interactions between nanomaterials and cells. We aimed to verify whether MWCNT electrical properties could affect the so called “charge-sensitive” cell parameters, interacting with cellular electrical activity. Human macrophages were challenged with two fully characterised MWCNT samples, one tested as-prepared (MWCNT), the other one purified (by annealing at 2400 °C) and better electro-conductive (a-MWCNT). Our findings show that a-MWCNTs are less cytotoxic but possess a higher inflammatory potential, as compared to MWCNTs. Moreover, only annealed and better conductive MWCNTs affect significantly the mitochondrial membrane polarity, the intracellular pH and the reorganisation of cytoskeleton actin filaments, cell functions strictly dependent on electro-chemical mechanisms. Based on our results, there is evidence for electro-chemical interactions taking place between cell membranes and electro-conductive MWCNTs. Such a specific behaviour could have wide-range applications in the biomedical field, not only concerning those cellular systems (neuronal and bone cells) sensitive to electrical stimuli, but also other cell systems.     

Dream interpretation and false beliefs.

Dream interpretation is a common practice in psychotherapy. In the research presented in this article, each participant saw a clinician who interpreted a recent dream report to be a sign that the participant had had a mildly traumatic experience before age 3 years, such as being lost for an extended time or feeling abandoned by his or her parents. This dream intervention caused a majority of participants to become more confident that they had had such an experience, even though they had previously denied it. These findings have implications for the use of dream material in clinical settings. In particular, the findings point to the possibility that dream interpretation may have unexpected side effects if it leads to beliefs about the past that may, in fact, be false. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FEM modelling and experimental characterization of microbeams in presence of residual stress

Out-of-plane bending tests are here used to experimentally validate some numerical models of microbeams actuated by the electric field. Out-of-plane bending microcantilevers and clamped–clamped microbeams often suffer the presence of residual strain and stress, respectively, which affect their static and dynamic behaviour and pull-in voltage. In case of microcantilever an accurate modelling has to include the effect of an initial curvature due to microfabrication process, while in double clamped microbeams constraints may impose a pre-loading caused by a tensile stress. So-called geometrical nonlinearity sometimes occurs, when microcantilever exhibits large displacement, or because of the mechanical coupling between axial and flexural behaviours in double clamped microbeams. Modelling this kind of nonlinearity is an additional goal of this study. Experiments demonstrated a good agreement with results of FEM approaches proposed. In the case of microbridges numerical models are used to identify the residual stress. A reverse analysis is implemented, the axial pre-stress is calculated by means of the measured pull-in voltage.     

Large-scale production of high-quality multi-walled carbon nanotubes: Role of precursor gas and of Fe-catalyst support

The crucial role of precursor gas (PG) and of catalyst support (CS) in the growth of multi-walled C nanotubes (MWCNTs) by iron-catalysed chemical vapour deposition (CVD) is evidenced. This is accomplished by comparing structural and morphological properties of MWCNTs synthesised by the use of different PGs (ethane and isobutane) and CSs (silica and alumina). The results of analyses, carried out on catalysts and C deposits by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS), thermo-gravimetry (TG) and X-ray diffraction (XRD), demonstrate that Al₂O₃-supported catalysts are more efficient than SiO₂-supported ones in decomposing hydrocarbons. The use of i-C₄H₁₀ as PG allows reducing Fe-encapsulation and improving yield (Y_C) and selectivity, so as the large-scale production (Y_C > 900 wt.%) of high-quality nanotubes can be operated even at moderate reaction temperature (600 °C) after proper calibration of Fe-load (29 wt.%) and catalyst reduction temperature (500 °C).