To date, electroconvulsive therapy (ECT) is the most potent treatment in severe depression. Although ECT has been successfully applied in clinical practice for over 70 years, the underlying ...mechanisms of action remain unclear. We used functional MRI and a unique data-driven analysis approach to examine functional connectivity in the brain before and after ECT treatment. Our results show that ECT has lasting effects on the functional architecture of the brain. A comparison of pre- and posttreatment functional connectivity data in a group of nine patients revealed a significant cluster of voxels in and around the left dorsolateral prefrontal cortical region (Brodmann areas 44, 45, and 46), where the average global functional connectivity was considerably decreased after ECT treatment (P < 0.05, family-wise error-corrected). This decrease in functional connectivity was accompanied by a significant improvement (P < 0.001) in depressive symptoms; the patients’ mean scores on the Montgomery Asberg Depression Rating Scale pre- and posttreatment were 36.4 (SD = 4.9) and 10.7 (SD = 9.6), respectively. The findings reported here add weight to the emerging "hyperconnectivity hypothesis" in depression and support the proposal that increased connectivity may constitute both a biomarker for mood disorder and a potential therapeutic target.
•Fractional Release Rates of two samples (in-vessel and ex-vessel) were obtained.•Fraction of Inventory in Aqueous Phase of Mo, Ba, Sr, Rh, La, etc. was obtained.•Geochemical modeling was performed ...to better understand experimental results.
On 11 March 2011, the Great East Japan Earthquake occurred and caused a severe nuclear accident at the Fukushima Daiichi Nuclear Power Station (1F). A policy for corium debris retrieval will be decided in the near future. To this end, debris management after removal from reactors must be optimized. From the viewpoint of cost and waiting for definitive solutions, interim or long-term underwater storage is one of the considered options after debris removal. Leaching data on the long term behavior of debris in water are therefore needed before debris removal. In addition, it is important to understand potential differences in leaching behaviors between debris and Spent Fuel (SF) to get comparative elements.
For these reasons, simulated in-vessel and ex-vessel corium debris, fabricated in the Colima experimental facility set up in the PLINIUS platform at CEA Cadarache, were selected and leaching experiments were carried out under oxidizing conditions. In parallel, geochemical modeling was performed to better understand the experimental concentrations, pH evolutions and secondary phase’s formation.
Finally, the Fractional Release Rates of the (U, Zr)O2 matrix for the two kinds of samples (in-vessel and ex-vessel) were found to be close to or one order of magnitude lower than that of SF under oxidizing conditions (from 10−6 to 10−7 per day) but the release processes are different. Indeed, the Fraction of Inventory in Aqueous Phase of Mo, Ba, Sr, Rh, La, Nd, Ce and Y tended to be higher than that of uranium and zirconium in this study whatever the element considered. The release of simulating PFs, including low volatile element like trivalent rare earths, does not appear to be fully controlled by that of the (U, Zr)O2 matrix from a macroscopic and average point of view. The FPs could be partially located outside the (U, Zr)O2 solid solution as a function of the corium history (quenching rate and thermal history, chemical interactions…). The location of inventories and their chemical forms are not very well known moreover uncertainties related to heterogeneity are important and may also impact the calculation of the global released fractions over time. For the ex-vessel sample, releases into the solution of the main concrete elements (Si, Ca, Mg) seem well correlated and dissociated from the behavior of the (U, Zr)O2 phase. Further studies are needed especially on real or prototypical corium approaching the conditions of the Fukushima accident. The study of simpler and model systems could also provide information on the reactivity of the (U, Zr)O2 matrix.
The growth of white matter during human adolescence shows a striking sexual dimorphism; the volume of white matter increases with age slightly in girls and steeply in boys. Here, we provide evidence ...supporting the role of androgen receptor (AR) in mediating the effect of testosterone on white matter. In a large sample of typically developing adolescents (n = 408, 204 males), we used magnetic resonance imaging and acquired T1-weighted and magnetization transfer ratio (MTR) images. We also measured plasma levels of testosterone and genotyped a functional polymorphism in the AR gene, namely the number of CAG repeats in exon 1 believed to be inversely proportional to the AR transcriptional activity. We found that the testosterone-related increase of white-matter volume was stronger in male adolescents with the lower versus higher number of CAG repeats in the AR gene, with testosterone explaining, respectively, 26 and 8% of variance in the volume. The MTR results suggest that this growth is not related to myelination; the MTR decreased with age in male adolescents. We speculate that testosterone affects axonal caliber rather than the thickness of the myelin sheath.
The oxide film formed on nickel base alloys at high temperature and high pressure water exhibits semi-conducting properties evidenced by photocurrent generation when exposed to monochromatic light. ...The use of macro- and micro-photoelectrochemical techniques (PEC and MPEC) aims to identify the different semiconductor phases and their distribution in the oxide film.
Three different nickel base alloys were corroded in recirculation loop at 325
°C in pressurised water reactor primary coolant conditions for different exposition durations.
PEC experiments on these materials enable to obtain macroscopic energy spectra showing three contributions. The first one, with a band gap around 2.2
eV, was attributed to the presence of nickel hydroxide and/or nickel ferrite. The second one, with a band gap around 3.5
eV, was attributed to Cr
2O
3. The last contribution, with a band gap in the range of 4.1–4.5
eV, was attributed to the spinel phase Ni
1−
x
Fe
x
Cr
2O
4. In addition, macroscopic potential spectra recorded at different energies highlight n-type semi-conduction behaviours for both oxides, Cr
2O
3 and Ni
1−
x
Fe
x
Cr
2O
4.
Moreover, MPEC images recorded at different energies exhibit contrasted regions in photocurrent, describing the distribution of nickel hydroxide and/or nickel ferrite and Cr
2O
3 in the oxide film at a micron scale.
It is concluded that PEC techniques represent a sensitive and powerful way to locally analyse the various semiconductor phases in the oxide scale.
Electroconvulsive therapy (ECT) is an effective treatment for depression but the extent and persistence of cognitive side-effects remain uncertain. It has been reported that there is little evidence ...that impairments last longer than up to 15 days post-ECT. However, relatively few studies have followed patients for even as long as 1 month post-ECT. Here we report results from a brief cognitive battery given prior to ECT and repeated five times up to 6 months post-ECT.
In a retrospective case-note study of routinely collected clinical data 126 patients treated with ECT completed two neuropsychological tests Cambridge Neuropsychological Test Automated Battery (CANTAB) spatial recognition memory (SRM) and Mini Mental State Examination (MMSE) and two subjective reports of memory function, prior to ECT. Patients were reassessed following ECT and at 1, 3 and 6 months post-ECT although not all patients completed all assessments.
Performance relative to pre-ECT baseline was significantly poorer at each post-ECT assessment up to 3 months post-ECT using the CANTAB SRM, but was improved at 6 months. Conversely, MMSE score showed improvements relative to baseline from 1 month post-ECT. Mood and subjective memory scores improved following ECT and were correlated with one another, but not with either neuropsychological measure.
The CANTAB SRM task revealed reversible cognitive deficiencies relative to a pre-ECT baseline for at least 3 months following ECT, while MMSE score and patients' subjective reports showed only improvement. Visuospatial memory scores eventually exceeded baseline 6 months post-ECT.
On-call schedules are associated with stress and disrupted sleep. In a recent study, under non-sleep deprived conditions, low and high-stress on-call conditions did not significantly impact sleep ...quality but did impact next day performance. Our aim was to determine whether quantitative electroencephalography (qEEG) would reflect changes in cortical activity in on-call conditions, predicting that the high-stress condition would display faster qEEG frequencies compared with the control and low-stress condition.
Twenty-four healthy male participants (age: 26.5 ± 4.0 yrs) spent four nights in a time-isolated sleep laboratory. The within-subjects, repeated measures experimental design assessed waking EEG, via the Karolinska Drowsiness Test (KDT) during four time-points across a control day and two experimental (on-call) days. Experimental days comprised a low-stress (LS – reading task) and high-stress (HS – speech task) condition and were counterbalanced. Mixed-models analysis was used to assess condition and time by EEG biomarkers: Alpha Attenuation Coefficient (AAC), Slowing Ratio (SR) and Scaling Exponent (SE).
Main effects were found for all three biomarkers by condition, with pairwise analysis reported. There was a significant difference in AAC between the LS condition (M = 1.26 ± =1.24) and HS condition (M = 1.01 ± 0.76 p = .02) indicating decreased alertness between LS and HS. A significant increase in SR between control (M = 7.1 ± 4.3) and LS (M = 10.1 ± 8.5 p = .0001), and a significant increase between the LS and HS (M = 7.8 ± 6.8 p = .018) showing greatest EEG slowing in the LS condition, reflecting of a passive, sleepier brain state. The SE was significantly higher in the LS (M = 1.09, ±0.17) condition compared with control (M = 1.0, ±0.11 p = .001) indicating decreased alertness in the LS task.
Using qEEG biomarkers, in contrast with our initial hypothesis, the current study found that compared with control, the LS condition resulted in greater EEG slowing. These findings have implications for on-call workers who engage in periods of passive attention and highlight a protective role task stress may play in maintaining alertness levels during on-call conditions.
► Ni-base alloy uniform corrosion in primary medium of Pressurised Water Reactor. ► Influence of alloy subsurface defects created by ion implantation on oxide layer. ► Defects in the alloy modify the ...crystallinity and the nucleation rate of the oxides. ► These modifications are linked to the change of oxidation kinetic curves.
Oxidation of Alloy 690 in PWR primary water conditions has been investigated, considering particularly the role played by subsurface structural defects. To simulate a defective surface state, Xe implantation has been set up on samples. Corrosion experiments were thereafter performed in a corrosion loop simulating the PWR medium with durations between 24
h and 1000
h. Microstructural observations and NRA measurements underlined the role played by defects on the crystallinity of the continuous oxide spinel layer, on the nucleation of Cr
2O
3 nodules and on the oxidation rate. The higher defects concentration seemed to modify the oxygen diffusion in the oxide scale.
•A fire-free method was used to convert 2ha of French Guianese forest to agriculture.•We measured in situ soil N2O fluxes and compared 4 land uses.•Soil N2O fluxes measured at Combi site ranged ...between −4.5 and 65.8gNha−1day−1.•Nitrogen inputs led to higher N2O fluxes from croplands compared to the forest.
In French Guiana, the population growth will result in an increase in demand for agricultural products and thus, will lead to an increase in the amount of tropical forests converted into cropland or pasture. Impacts of different agricultural systems on greenhouse gas (GHG) fluxes have not been studied in French Guiana. In this context, the fire-free chop-and-mulch method was used to convert a tropical forest site to agriculture. This study focused on soil nitrous oxide (N2O) emissions and we compared four land uses: (1) the undisturbed tropical forest, (2) recently converted grassland and recently converted croplands (fertilized soybean/maize rotation) with either (3) disk tillage or (4) no tillage.
N2O measurements were obtained through the chamber technique and conducted over a 1-year period (measurements began 19 months after the forest was cleared). N2O fluxes were related to soil parameters measured at each sampling date: nitrate and ammonium contents, gravimetric water content (GWC) and temperature.
Through the entire period, the mean (±standard error) and median N2O fluxes were 3.8±0.5 and 2.7gNha−1day−1, respectively for undisturbed tropical forest and 2.4±0.9 and 0.8gNha−1day−1, respectively for grassland (mowed Brachiaria ruziziensis). For croplands, no significant difference was found for N2O emissions between both agricultural practices. The mean (±standard error) and median N2O fluxes were 8.5±1.2 and 4.0gNha−1day−1, respectively for disk tillage plots and 8.5±1.3 and 3.6gNha−1day−1, respectively for no tillage plots. Nitrogen inputs (due to the application of fertilizer or due to the mineralization of crop residues) led to higher N2O fluxes, resulting in significantly higher mean N2O emissions from croplands compared to the forest, when only considering land use effect on N2O fluxes in a statistical model. The soil nitrate content, GWC and temperature had a significant positive effect on N2O fluxes. Taking into account these soil parameters in another statistical model, N2O emissions from croplands were not higher than the natural N2O emissions from tropical forest soils. Our results suggest that, if more forest will have to be converted in the course of the expected population growth in French Guiana, it could have low impact on the soil N2O fluxes (similar to natural fluxes from forest) with the improving of farming techniques (for example modification of the splitting of N-fertilizer) in the cropping plots.
The purpose of this study was to examine sex differences in the maturation of white matter during adolescence (12 to 18 years of age). We measured lobular volumes of white matter and white-matter ...“density” throughout the brain using T1-weighted images, and estimated the myelination index using magnetisation-transfer ratio (MTR). In male adolescents, we observed age-related increases in white-matter lobular volumes accompanied by decreases in the lobular values of white-matter MTR. White-matter density in the putative cortico-spinal tract (pCST) decreased with age. In female adolescents, on the other hand, we found only small age-related increase in white-matter volumes and no age-related changes in white-matter MTR, with the exception of the frontal lobe where MTR increased. White-matter density in the pCST also increased with age. These results suggest that sex-specific mechanisms may underlie the growth of white matter during adolescence. We speculate that these mechanisms involve primarily age-related increases in axonal calibre in males and increased myelination in females.
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