Effects of plasma treatments of polypropylene adhesive joints used in the automotive industry

Plasma treatment has been used in recent years to activate the surfaces of adhesive substrates and thus as an adhesion promoter between adhesive and substrates. The use of plasma treatments is widely adopted in the automotive industries especially for polymers that present low surface energy, such as polypropylene. In this work, polypropylene substrates used in the automotive industries have been treated with two different techniques: vacuum and atmospheric plasma. Then, polyurethane and methacrylate adhesives have been used to bond single lap joints (SLJs). Typically, these two adhesives cannot bond polypropylene substrates without surface treatments. An experimental plan has been designed to investigate the process parameters that can increase the functional polar groups (FPGs) maximizing the adhesion strength. Besides the types of plasma, two different gas carriers (air and nitrogen) and different treatment times have been investigated. The substrates, treated and not treated, have been assessed through scanning electron microscopy, energy-dispersive X-ray analysis, and Fourier-transform infrared spectroscopy to quantitatively assess the increment of FPGs after the different treatments. The experimental plan shows that the atmospheric plasma can improve the surface of the substrates by using a smaller time. Mechanical tests on SLJs show that methacrylate and polyurethane cannot bond polypropylene substrates without the plasma treatment. On the other hand, the treated substrates can form a strong bonding with the adhesive since all SLJs exhibit a substrate failure. Mechanical tests have been also carried out after three different aging cycles showing that the adopted plasma treatment is not affected by the aging cycles

A complementary approach to estimate the internal pressure of fission gas bubbles by SEM-SIMS-EPMA in irradiated nuclear fuels

International audienceThe behaviour of gases produced by fission is of great importance for nuclear fuel in operation. Within this context, a decade ago, a general method for the characterisation of the fission gas including gas bubbles in an irradiated UO$_2$ nuclear fuel was developed and applied to determine the bubbles internal pressure. The method consists in the determination of the pressure, over a large population of bubbles, using three techniques: SEM, EPMA and SIMS. In this paper, a complementary approach using the information given by the same techniques is performed on an isolated bubble under the surface and is aiming for a better accuracy compared to the more general measurement of gas content. SEM and EPMA enable the detection of a bubble filled with xenon under the surface. SIMS enables the detection of the gas filling the bubble. The quantification is achieved using the EPMA data as reference at positions where no or nearly no bubbles are detected

Metabotropic glutamate receptor blockade reduces preservation damage in livers from donors after cardiac death

We previously demonstrated that the blockade of mGluR5 by 2-methyl-6(phenylethynyl)pyridine (MPEP) reduces both cold and warm ischemia/reperfusion injury. Here we evaluated whether MPEP reduces the hepatic preservation injury in rat livers from cardiac-death-donors (DCDs). Livers from DCD rats were isolated after an in situ warm ischemia (30 min) and preserved for 22 h at 4 °C with UW solution. Next, 10 mg/Kg MPEP or vehicle were administered 30 min before the portal clamping and added to the UW solution (3 µM). LDH released during washout was quantified. Liver samples were collected for iNOS, eNOS, NO, TNF-α, ICAM-1, caspase-3 and caspase-9 protein expression and nuclear factor-erythroid-2-related factor-2 (Nrf2) gene analysis. Lower LDH levels were detected in control grafts versus DCD groups. An increase in eNOS and NO content occurred after MPEP treatment; iNOS and TNF-α content was unchanged. ICAM-1 expression was reduced in the MPEP-treated livers as well as the levels of caspase-3 and caspase-9. Nrf2, oxidative stress-sensitive gene, was recovered to control value by MPEP. These results suggest that MPEP can be used to reclaim DCD livers subjected to an additional period of cold ischemia during hypothermic storage. MPEP protects against apoptosis and increased eNOS, whose overexpression has been previously demonstrated to be protective in hepatic ischemia/reperfusion damage

Early-Life Critical Windows of Susceptibility to Manganese Exposure and Sex-Specific Changes in Brain Connectivity in Late Adolescence

Background: Early-life environmental exposures during critical windows (CWs) of development can impact life course health. Exposure to neuroactive metals such as manganese (Mn) during prenatal and early postnatal CWs may disrupt typical brain development, leading to persistent behavioral changes. Males and females may be differentially vulnerable to Mn, presenting distinctive CWs to Mn exposure. Methods: We used magnetic resonance imaging to investigate sex-specific associations between early-life Mn uptake and intrinsic functional connectivity in adolescence. A total of 71 participants (15-23 years old; 53% female) from the Public Health Impact of Manganese Exposure study completed a resting-state functional magnetic resonance imaging scan. We estimated dentine Mn concentrations at prenatal, postnatal, and early childhood periods using laser ablation-inductively coupled plasma-mass spectrometry. We performed seed-based correlation analyses to investigate the moderating effect of sex on the associations between Mn and intrinsic functional connectivity adjusting for age and socioeconomic status. Results: We identified significant sex-specific associations between dentine Mn at all time points and intrinsic functional connectivity in brain regions involved in cognitive and motor function: 1) prenatal: dorsal striatum, occipital/frontal lobes, and middle frontal gyrus; 2) postnatal: right putamen and cerebellum; and 3) early childhood: putamen and occipital, frontal, and temporal lobes. Network associations differed depending on exposure timing, suggesting that different brain networks may present distinctive CWs to Mn. Conclusions: These findings suggest that the developing brain is vulnerable to Mn exposure, with effects lasting through late adolescence, and that females and males are not equally vulnerable to these effects. Future studies should investigate cognitive and motor outcomes related to these associations

Associations of a metal mixture measured in multiple biomarkers with IQ: Evidence from italian adolescents living near ferroalloy industry

BACKGROUND: Research on the health effects of chemical mixtures has focused mainly on early life rather than adolescence, a potentially important developmental life stage. OBJECTIVES: We examined associations of a metal mixture with general cognition in a cross-sectional study of adolescents residing near ferromanga-nese industry, a source of airborne metals emissions. METHODS: We measured manganese (Mn), lead (Pb), copper (Cu), and chromium (Cr) in hair, blood, urine, nails, and saliva from 635 Italian adolescents 10–14 years of age. Full-scale, verbal, and performance intelligence quotient (FSIQ, VIQ, PIQ) scores were assessed using the Wechsler Intelligence Scale for Children-III. Multivariable linear regression and Bayesian kernel machine regression (BKMR) were used to estimate associations of the metal mixture with IQ. In secondary analyses, we used BKMR’s hierarchical variable selection option to inform biomarker selection for Mn, Cu, and Cr. RESULTS: Median metal concentrations were as follows: hair Mn, 0:08 lg=g; hair Cu, 9:6 lg=g; hair Cr, 0:05 lg=g; and blood Pb, 1:3 lg=dL. Adjusted models revealed an inverted U-shaped association between hair Cu and VIQ, consistent with Cu as an essential nutrient that is neurotoxic in excess. At low levels of hair Cu (10th percentile, 5:4 lg=g), higher concentrations (90th percentiles) of the mixture of Mn, Pb, and Cr (0:3 lg=g, 2:6 lg=dL, and 0:1 lg=g, respectively) were associated with a 2.9 (95% CI: −5:2, −0:5)–point decrease in VIQ score, compared with median concentrations of the mixture. There was suggestive evidence of interaction between Mn and Cu. In secondary analyses, saliva Mn, hair Cu, and saliva Cr were selected as the biomarkers most strongly associated with VIQ score. DISCUSSION: Higher adolescent levels of Mn, Pb, and Cr were associated with lower IQ scores, especially at low Cu levels. Findings also support fur-ther investigation into Cu as both beneficial and toxic for neurobehavioral outcomes

Metabolic Outcomes in Southern Italian Preadolescents Residing Near an Industrial Complex: The Role of Residential Location and Socioeconomic Status

Evidence suggests that environmental exposures and socioeconomic factors may interact to produce metabolic changes in children. We assessed the influence of residential location and socioeconomic status (SES) on pediatric body mass index (BMI) Z-score and fasting blood glucose (FBG) concentration. Participants included 214 children aged 6-11 years who live near a large industrial complex in Taranto, Italy. Participants were grouped into residential zones based on the distance between their home address and the complex periphery (Zone 1: 0.000-4.999 km, Zone 2: 5.000-9.999 km, Zone 3: 10.000-15.000 km). BMI Z-scores were calculated via World Health Organization (WHO) pediatric reference curves. FBG was obtained via venous blood sampling. Closer residential location to the industrial complex on the order of 5.000 km was significantly associated with worsened metabolic outcomes, particularly in female children. Zone 1 participants had higher BMI-adjusted FBG than Zone 2 and 3 participants (p < 0.05 versus Zone 2; p < 0.01 versus Zone 3). SES did not significantly influence BMI-adjusted FBG. Moreover, BMI Z-scores indicated high rates of overweight (22.0%) and obesity (22.9%) in the cohort. BMI Z-score was not significantly associated with SES or residential zone but was negatively associated with maternal education level (p < 0.05). These results offer new evidence that residing near industrial activity may predict adverse effects on child metabolic health

Accelerating the Evolution of Nonhuman Primate Neuroimaging

Nonhuman primate neuroimaging is on the cusp of a transformation, much in the same way its human counterpart was in 2010, when the Human Connectome Project was launched to accelerate progress. Inspired by an open data-sharing initiative, the global community recently met and, in this article, breaks through obstacles to define its ambitions

New methods to estimate the internal pressure of xenon in fission bubbles using SEM-EPMA-SIMS and EBSD in irradiated fuels

International audienceDuring irradiation, in Pressurized Water Reactors, gaseous fission products are created (xenon and krypton) in the fuel pellets and form bubbles distributed heterogeneously. During fast heating in an accident situation, the internal pressure of nanoscale bubbles increases, producing stresses at grain boundaries. As part of a thesis in collaboration between the CEA Cadarache and MSMP Laboratory (Arts et Metiers ParisTech, Aix-en-Provence), a research program has been undertaken to develop new methods to evaluate the internal pressure of fission gas bubbles in irradiated fuels. The first experimental method was developed for the characterization of a large number of pressurized bubbles in an irradiated UO$_2$ nuclear fuel using SIMS, EPMA and SEM. The method is now performed by selecting with EPMA an area where few pressurized bubbles are present under the sample surface. The SIMS, Secondary Ion Mass Spectrometry, is carried out to open these bubbles and collect the amount of xenon in both the matrix and the bubbles. The EPMA, enables the calibration of the SIMS in order to provide quantitative results. SEM, provides information on the number and shape of the bubbles. The quantification of xenon in the bubbles by SIMS coupled to their size measured by SEM make it possible to obtain the atomic volume. Through adapted equations of state, the pressure of xenon in these bubbles is then estimated.The second method consists in the measurement of the local deformation around a bubble by Electron Back Scatter Diffraction (EBSD). The diffraction patterns are analyzed by cross-correlation to obtain the elastic deformation and rotation tensors. In parallel, a mechanical model by finite elements is developed to determine the bubble's internal pressure. At this point, the method is calibrated with a mechanical test by four points bending of a monocrystal silicon beam. The test results are compared to a relevant mechanical model.These experimental data will provide new points of validation for the models to predict the behavior of the fuel during nominal irradiation and accidental situations

Past, present and future of transcranial magnetic stimulation (TMS) in the treatment of psychiatric disorders

Transcranial magnetic stimulation (TMS) is a brain stimulation technique used for the treatment of major depression and other psychiatric disorders. Initially used as a research tool in neurophysiology, TMS has been subsequently extended to the therapeutic area of depressive disorders and approved in many countries for this purpose. TMS uses magnetic fields to deliver electricity into specific areas of the cerebral cortex, mainly the dorso-lateral prefrontal cortex. Several randomized clinical trials (RCTs) conducted with TMS over the last decade have allowed its approval by the FDA for the treatment of major depressive episodes with poor response to standard antidepressants. In addition, meta-analyses and international treatment guidelines have more recently defined stimulation parameters and safety standards. Future directions in the field should further explore the clinical efficacy and safety of specific forms of TMS like deep TMS and theta burst stimulation, which allow to reach deeper anatomic targets and to shorten the overall duration of stimulation. The utility of maintenance session and the interaction with specific psychotropic compounds represent areas that need to be further investigated as well. To date, TMS is likely the non-invasive brain stimulation intervention with the strongest evidence in terms of efficacy in psychiatric disorders, as documented by RCTs and meta-analyses. Nonetheless, the efficacy of TMS needs to be further investigated in other psychiatric disorders with preliminary, encouraging results in different fields. The tolerability and safety profile of TMS are advantageous, the technique being non-invasive, generally well-accepted and devoid of systemic side-effects