Disrupted White Matter Microstructure of the Cerebellar Peduncles in Scholastic Athletes After Concussion.

Concussion, or mild traumatic brain injury (mTBI), is a major public health concern, linked with persistent post-concussive syndrome, and chronic traumatic encephalopathy. At present, standard clinical imaging fails to reliably detect traumatic axonal injury associated with concussion and post-concussive symptoms. Diffusion tensor imaging (DTI) is an MR imaging technique that is sensitive to changes in white matter microstructure. Prior studies using DTI did not jointly investigate white matter microstructure in athletes, a population at high risk for concussive and subconcussive head traumas, with those in typical emergency room (ER) patients. In this study, we determine DTI scalar metrics in both ER patients and scholastic athletes who suffered concussions and compared them to those in age-matched healthy controls. In the early subacute post-concussion period, athletes demonstrated an elevated rate of regional decreases in axial diffusivity (AD) compared to controls. These regional decreases of AD were especially pronounced in the cerebellar peduncles, and were more frequent in athletes compared to the ER patient sample. The group differences may indicate differences in the mechanisms of the concussive impacts as well as possible compound effects of cumulative subconcussive impacts in athletes. The prevalence of white matter abnormality in cerebellar tracts lends credence to the hypothesis that post-concussive symptoms are caused by shearing of axons within an attention network mediated by the cerebellum, and warrant further study of the correlation between cerebellar DTI findings and clinical, neurocognitive, oculomotor, and vestibular outcomes in mTBI patients

Chronic Post-Concussion Neurocognitive Deficits. I. Relationship with White Matter Integrity.

We previously identified visual tracking deficits and associated degradation of integrity in specific white matter tracts as characteristics of concussion. We re-explored these characteristics in adult patients with persistent post-concussive symptoms using independent new data acquired during 2009-2012. Thirty-two patients and 126 normal controls underwent cognitive assessments and MR-DTI. After data collection, a subset of control subjects was selected to be individually paired with patients based on gender and age. We identified patients' cognitive deficits through pairwise comparisons between patients and matched control subjects. Within the remaining 94 normal subjects, we identified white matter tracts whose integrity correlated with metrics that indicated performance degradation in patients. We then tested for reduced integrity in these white matter tracts in patients relative to matched controls. Most patients showed no abnormality in MR images unlike the previous study. Patients' visual tracking was generally normal. Patients' response times in an attention task were slowed, but could not be explained as reduced integrity of white matter tracts relating to normal response timing. In the present patient cohort, we did not observe behavioral or anatomical deficits that we previously identified as characteristic of concussion. The recent cohort likely represented those with milder injury compared to the earlier cohort. The discrepancy may be explained by a change in the patient recruitment pool circa 2007 associated with an increase in public awareness of concussion

Mercury pollution caused by artisanal gold mining the Ocoña river Valley, Peru

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Microbial diversity dynamics in a methanogenic-sulfidogenic UASB reactor

In this study, the long-term performance and microbial dynamics of an Upflow Anaerobic Sludge Blanket (UASB) reactor targeting sulfate reduction in a SOx emissions treatment system were assessed using crude glycerol as organic carbon source and electron donor under constant S and C loading rates. The reactor was inoculated with granular sludge obtained from a pulp and paper industry and fed at a constant inlet sulfate concentration of 250 mg S-SO42−L−1 and a constant C/S ratio of 1.5 ± 0.3 g Cg−1 S for over 500 days. Apart from the regular analysis of chemical species, Illumina analyses of the 16S rRNA gene were used to study the dynamics of the bacterial community along with the whole operation. The reactor was sampled along the operation to monitor its diversity and the changes in targeted species to gain insight into the performance of the sulfidogenic UASB. Moreover, studies on the stratification of the sludge bed were performed by sampling at different reactor heights. Shifts in the UASB performance correlated well with the main shifts in microbial communities of interest. A progressive loss of the methanogenic capacity towards a fully sulfidogenic UASB was explained by a progressive wash-out of methanogenic Archaea, which were outcompeted by sulfate-reducing bacteria. Desulfovibrio was found as the main sulfate-reducing genus in the reactor along time. A progressive reduction in the sulfidogenic capacity of the UASB was found in the long run due to the accumulation of a slime-like substance in the UASB

The use of mercury for gold recovering in the artisanal gold mining from the Mapiri river basin, Apolobamba, Bolivia

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Environmental pollution produced by gold artisanal mining in the Mapiri river basin, Apolobamba, Bolivia

Mining activity is very important in Bolivia since colonial times. Today it has been reactivated, especially gold mining, due to rise in metal prices. Artisanal and small-scale mining activities are abundant in the protected area of Apolobamba, near the border with Peru. Here mercury is used to recovery gold by obtaining an Hg-Au amalgam. This manipulation with mercury causes an important environmental impact in the area. The present work is a preliminary study of the contamination of the Mapiri river basin in the Apolobamba area. In the head of this basin, located at more than 4000 m above sea level, gold is mined from hydrothermal gold deposits of Paleozoic age. We have sampled several mining sites from this area, in particular the ones known as Viscachani, Flor de Mayo and Chojlaya, located in the proximity of the head area of the Mapiri river basin. These mining sites were in activity during the present sampling campaign. Different metals were measured by means of XRF (Se, As, Cu, Zn, Cd, Pb, Hg) in tailing samples from the different gold mining sites. In addition mercury concentrations were measured in water and in vegetation close to the processing areas by means of atomic absorption spectrometry with Zeeman effect (LUMEX RA-915 Equipment). Tailings are mainly constituted by quartz with minor contents of clay minerals and sulphides. The most abundant sulphides are galena and arsenopyrite. Chalcopyrite, sphalerite, pyrite and sulphosalts also occur in minor amounts, as well as minor secondary minerals. Gold content, after recovery with mercury, is high, between 4.56 ppm and 10.35 ppm. The Hg content of the tailings ranges from 149 to 1027 ppm. Lixiviable mercury from these samples ranges between 30.10 and 859.94 ng l-1. Water released from the tailings contains between 0.1 and 5.7 ppb of Hg. Studied vegetation typical of the area has high Hg contents, between 162 and 219 ppm. In addition there is a high arsenic content in all the studied tailings, except in those from the Viscachani mining site, where concentrations of this element ranges from 456 ppm to 18540 ppm. The Pb content usually ranges from 337 to 939 ppm. The Chojlaya mining site tailing has exceptionally high values of heavy metals: Pb content is between 2.26 and 3.27 wt.%, Cd ranges from 160 to 228 ppm, Zn from 194 to 794 ppm, Cu from 847 to 1052 ppm and Se from 105 to 187 ppm. These contents also contribute to an environmental pollution. In conclusion the gold mining activities in the Mapiri river basin produce and intense environmental pollution, mainly related to mercury and arsenic contents in the proximity of these mining activities. After processing, tailings still contain important amounts of gold suggesting that the amalgamation method is not effective to gold recovering.Peer ReviewedPostprint (published version

Factors predicting mental health in youth during the first COVID-19 lockdown in Spain

[EN]Background: The first COVID-19 lockdown decreed in Spain by the government resulted in a significant disruption in the daily lives of youth that may have affected their mental health. The aim of this study was to identify factors that influenced youth mental health during this period. Methods: Between March and May 2020, a sample of 1205 youths (age range 18–24 years) from across Spain completed a questionnaire that assessed sociodemographic, mental health, loneliness, coping with humour and healthy habits. Data were analysed using Structural Equation Modelling. Results: The proposed model showed good fit values, and significant variables explained 37% of mental health. Loneliness, coping humour, healthy and unhealthy habits, and gender significantly predicted youth mental health. Conclusions: The consequences of the pandemic and confinement derived from COVID-19 seemed to be especially severe for youth, increasing their mental health vulnerability. It is recommended that evaluating the long-term effects of confinement on this population, the mental health needs they may have and the support resources that would help meet them in situations of isolation, paying special attention to females

Exploring the performance limits of a sulfidogenic UASB during the long-term use of crude glycerol as electron donor

SOx contained in flue gases and S-rich liquid effluents can be valorized to recover elemental sulfur in a two-stage bioscrubbing process. The reduction of sulfate to sulfide is the most crucial stage to be optimized. In this study, the long-term performance of an up-flow anaerobic sludge blanket (UASB) reactor using crude glycerol as electron donor was assessed. The UASB was operated for 400 days with different sulfate and organic loading rates (SLR and OLR, respectively) and a COD/S-SO42− ratio ranging from 3.8 g O2 g−1 S to 5.4 g O2 g−1 S. After inoculation with methanogenic, granular biomass, the competition between sulfate-reducing and methanogenic microorganisms determined to what extent dissolved sulfide and methane were produced. After the complete washout of methanogens, which was revealed by next-generation sequencing analysis, the highest S-EC was reached in the system. The highest average sulfate elimination capacity (S-EC = 4.3 kg S m−3d−1) was obtained at a COD/S-SO42− ratio of 5.4 g O2 g−1 S and an OLR of 24.4 kg O2 m−3d−1 with a sulfate removal efficiency of 94%. The conversion of influent COD to methane decreased from 12% to 2.5% as the SLR increased while a large fraction of acetate (35% of the initial COD) was accumulated. Our data indicate that crude glycerol can promote sulfidogenesis. However, the disappearance of methanogens in the long-term due to the out competition by sulfate reducing bacteria, lead to such large accumulation of acetate