Chlorinated ethene plume evolution after source thermal remediation: Determination of degradation rates and mechanisms

The extent, mechanism(s), and rate of chlorinated ethene degradation in a large tetrachloroethene (PCE) plume were investigated in an extensive sampling campaign. Multiple lines of evidence for this degradation were explored, including compound-specific isotope analysis (CSIA), dual C-Cl isotope analysis, and quantitative real-time polymerase chain reaction (qPCR) analysis targeting the genera Dehalococcoides and Dehalogenimonas and the genes vcrA, bvcA, and cerA. A decade prior to this sampling campaign, the plume source was thermally remediated by steam injection. This released dissolved organic carbon (DOC) that stimulated microbial activity and created reduced conditions within the plume. Based on an inclusive analysis of minor and major sampling campaigns since the initial site characterization, it was estimated that reduced conditions peaked 4 years after the remediation event. At the time of this study, 11 years after the remediation event, the redox conditions in the aquifer are returning to their original state. However, the DOC released from the remediated source zone matches levels measured 3 years prior and plume conditions are still suitable for biotic reductive dechlorination. Dehalococcoides spp., Dehalogenimonas spp., and vcrA, bvcA, and cerA reductive dehalogenase genes were detected close to the source, and suggest that complete, biotic PCE degradation occurs here. Further downgradient, qPCR analysis and enriched δ¹³C values for cis-dichloroethene (cDCE) suggest that cDCE is biodegraded in a sulfate-reducing zone in the plume. In the most downgradient portion of the plume, lower levels of specific degraders supported by dual C-Cl analysis indicate that the biodegradation occurs in combination with abiotic degradation. Additionally, 16S rRNA gene amplicon sequencing shows that organizational taxonomic units known to contain organohalide-respiring bacteria are relatively abundant throughout the plume. Hydraulic conductivity testing was also conducted, and local degradation rates for PCE and cDCE were determined at various locations throughout the plume. PCE degradation rates from sampling campaigns after the thermal remediation event range from 0.11 to 0.35 yr^-1. PCE and cDCE degradation rates from the second to the third sampling campaigns ranged from 0.08 to 0.10 yr^-1 and 0.01 to 0.07 yr^-1, respectively. This is consistent with cDCE as the dominant daughter product in the majority of the plume and cDCE degradation as the time-limiting step. The extensive temporal and spatial analysis allowed for tracking the evolution of the plume and the lasting impact of the source remediation and illustrates that the multiple lines of evidence approach is essential to elucidate the primary degradation mechanisms in a plume of such size and complexity.

AMS-100: The Next Generation Magnetic Spectrometer in Space - An International Science Platform for Physics and Astrophysics at Lagrange Point 2

The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of 100 m2 sr and to be operated for at least ten years at the Sun-Earth Lagrange Point 2. Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is instrumented with a silicon tracker reaching a maximum detectable rigidity of 100 TV and a calorimeter system that is 70 radiation lengths deep, equivalent to four nuclear interaction lengths, which extends the energy reach for cosmic-ray nuclei up to the PeV scale, i.e. beyond the cosmic-ray knee. Covering most of the sky continuously, AMS-100 will detect high-energy gamma rays in the calorimeter system and by pair conversion in the thin solenoid, reconstructed with excellent angular resolution in the silicon tracker.

P1824Aortic wall shear stress in bicuspid aortic valve disease - 10-year follow-up

Introduction

Bicuspid aortic valve (BAV) disease leads to deviant complex helical flow patterns in the aorta - especially in the mid-ascending (AoA) part. In association with congenital BAV, aortic wall alterations such as aortic dilatation and dissection may occur. Among others, wall shear stress (WSS) could be one parameter to contribute to the prediction of the long-term outcome of patients with BAV. 4D-flow in cardiovascular magnetic resonance has been established as a valid method to estimate WSS.

Purpose

The aim of this study is to reevaluate WSS and comparing it to values generated in the same patient cohort with bicuspid aortic valve disease in 2008. No one of the above had aortic dilation in 2008 but proven helical flow pattern. The long term follow-up study might show changes in WSS over the period of ten years.

Methods

Ten complete 4D flow datasets of patients (age at follow-up: median 34.5 years; range 19–41 years) with bicuspid aortic valve disease without enlargement of the aorta were obtained in 2008 and reevaluated in 2018/2019 in the same patient collective. Mean WSS values were calculated with identical specific software tools. All data were analyzed by two experienced investigators.

Results

Aortic diameters at the level of the mid AoA did not change significantly in the 10-year period. The WSS values were lower in 2018 at all levels of the ascending aorta (Table 1). Indexed aortic diameters at the level of the mid ascending aorta did not change, median difference 0.06 cm/m2 (range −0.1 cm/m2 to 0.2 cm/m2; p=0.28), absolute values of indexed AoA diameters in 2018/2019 ranged from 1.27 cm/m2 to 2.2 cm/m2 (median 1.76 cm/m2).

Table 1 WSS magnitudinal [N/m2] 2008 (n=10) 2018 (n=10) Median difference p-value median range median range Level aortic bulb 0.95 0.80–1.46 0.42 0.34–0.82 −0.53 <0.01 Level mid ascending aorta 0.72 0.40–0.98 0.39 0.34–0.59 −0.33 <0.01 Level brachiocephalic trunc (BCT) 0.71 0.38–1.03 0.40 0.37–0.61 −0.31 <0.01

Conclusions

Indexed AoA diameters in BAV disease did not change significantly over a 10-year period. WSS of AoA was less compared to values generated in 2008. This might be explained by a slight alteration in hemodynamic flow patterns by the aging aorta, but not by changes of the aortic diameters. Possibly a drop of WSS in BAV could serve as a marker for a benign long term course.

[Medical confidentiality]

Medical confidentiality is a fundamental prerequisite in the patient-physician relationship based on trust and goes back to the Hippocratic oath. It is clearly defined in the German Constitution as well as the medical professional code of conduct. A breach of confidentiality can result in criminal sanctions and professional consequences as well as civil claims for damages and compensation by the affected patients. In routine clinical practice situations repeatedly occur which lead to uncertainty regarding the limits of confidentiality, the right to silence and the obligation to disclosure. The purpose of this article is to explain the legal foundations of medical confidentiality, the right to silence and the obligation to disclosure and to provide practical support for critical questions in routine clinical practice.

Subject specificity of the correlation between large-scale structural and functional connectivity

Structural connectivity (SC), the physical pathways connecting regions in the brain, and functional connectivity (FC), the temporal coactivations, are known to be tightly linked. However, the nature of this relationship is still not understood. In the present study, we examined this relation more closely in six separate human neuroimaging datasets with different acquisition and preprocessing methods. We show that using simple linear associations, the relation between an individual's SC and FC is not subject specific for five of the datasets. Subject specificity of SC-FC fit is achieved only for one of the six datasets, the multimodal Glasser Human Connectome Project (HCP) parcellated dataset. We show that subject specificity of SC-FC correspondence is limited across datasets due to relatively small variability between subjects in SC compared with the larger variability in FC.

Differentiation of Alzheimer's disease based on local and global parameters in personalized Virtual Brain models

Alzheimer's disease (AD) is marked by cognitive dysfunction emerging from neuropathological processes impacting brain function. AD affects brain dynamics at the local level, such as changes in the balance of inhibitory and excitatory neuronal populations, as well as long-range changes to the global network. Individual differences in these changes as they relate to behaviour are poorly understood. Here, we use a multi-scale neurophysiological model, “The Virtual Brain (TVB)”, based on empirical multi-modal neuroimaging data, to study how local and global dynamics correlate with individual differences in cognition. In particular, we modeled individual resting-state functional activity of 124 individuals across the behavioural spectrum from healthy aging, to amnesic Mild Cognitive Impairment (MCI), to AD. The model parameters required to accurately simulate empirical functional brain imaging data correlated significantly with cognition, and exceeded the predictive capacity of empirical connectomes.

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Modeled local and global dynamics correlate with individual cognition in Alzheimer's.

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Proof of concept of The Virtual Brain to characterize individual dynamics

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Brain-behaviour relations depend on the network modeled (whole brain or limbic).

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Model parameters predict cognition better than metrics of neuroimaging data.

Childhood maltreatment, postnatal distress and the protective role of social support

The postpartum period is a vulnerable period for women with a history of childhood maltreatment. This study investigated the association between childhood maltreatment and postnatal distress three months postpartum and examined the role of social support provided by different sources (intimate partner, parents, parents-in-law, and friends). Analyses are based on N=66 women, who were screened for maltreatment experiences shortly after parturition with the Childhood Trauma Questionnaire. Their levels of postnatal distress (symptoms of depression, anxiety, and stress; assessed with the Hospital Anxiety and Depression Scale and the 4-Item version of the Perceived Stress Scale) and postpartum social support (measured with the Postpartum Social Support Questionnaire) were assessed three months postpartum. Adjusting for educational level and the experience of a recent stressful event, childhood maltreatment was directly associated with higher levels of postnatal distress. Social support provided by friends moderated this association in a heteroscedastic regression analysis. No moderating effect was observed for support provided by the own parents, the intimate partner, or parents-in-law. The association between childhood maltreatment and postnatal distress was not mediated by social support. Additional analyses revealed no main, moderating, or mediating effects of satisfaction with support. Results suggest that support provided by friends may promote resilience during the postpartum period in women with a history of childhood maltreatment. Efforts to better understand the role of postpartum support and mechanisms that may enhance a mother's ability to develop and maintain supportive friendships may be promising for guiding preventive interventions.

Homer1 (VesL-1) in the rat esophagus: focus on myenteric plexus and neuromuscular junction

Homer1, a scaffolding protein of the postsynaptic density (PSD), enriched at excitatory synapses is known to anchor and modulate group I metabotropic glutamate receptors (mGluRs) and different channel- and receptor-proteins. Homer proteins are expressed in neurons of different brain regions, but also in non-neuronal tissues like skeletal muscle. Occurrence and location of Homer1 and mGluR5 in myenteric plexus and neuromuscular junctions (NMJ) of rat esophagus have yet not been characterized. We located Homer1 and mGluR5 immunoreactivity (-iry) in rat esophagus and focused on myenteric neurons, intraganglionic laminar endings (IGLEs) and NMJs, using double- and triple-label immunohistochemistry and confocal laser scanning microscopy. Homer1-iry was found in a subpopulation of vesicular glutamate transporter 2 (VGLUT2) positive IGLEs and cholinergic varicosities within myenteric ganglia, but neither in nitrergic nor cholinergic myenteric neuronal cell bodies. Homer1-iry was detected in 63% of esophageal and, for comparison, in 35% of sternomastoid NMJs. Besides the location in the PSD, Homer1-iry colocalized with cholinergic markers, indicating a presynaptic location in coarse VAChT/CGRP/NF200- immunoreactive (-ir) terminals of nucleus ambiguus neurons supplying striated esophageal muscle. mGluR5-iry was found in subpopulations of myenteric neuronal cell bodies, VGLUT2-ir IGLEs and cholinergic varicosities within the myenteric neuropil and NMJs of esophagus and sternomastoid muscles. Thus, Homer1 may anchor mGluR5 at presynaptic sites of cholinergic boutons at esophageal motor endplates, in a small subpopulation of VGLUT2-ir IGLEs and cholinergic varicosities within myenteric ganglia possibly modulating Ca²⁺-currents and neurotransmitter release.

Enhanced viral clearance and reduced leukocyte infiltration in experimental herpes encephalitis after intranasal infection of CXCR3-deficient mice

Herpes simplex virus type 1 (HSV-1) encephalitis (HSE) is the most common fatal sporadic encephalitis in developed countries. There is evidence from HSE animal models that not only direct virus-mediated damage caused but also the host's immune response contributes to the high mortality of the disease. Chemokines modulate and orchestrate this immune response. Previous experimental studies in HSE models identified the chemokine receptor CXCR3 and its ligands as molecules with a high impact on the course of HSE in mouse models. In this study, the role of the chemokine receptor CXCR3 was evaluated after intranasal infection with the encephalitogenic HSV-1 strain 17 syn⁺ using CXCR3-deficient mice (CXCR3^-/-) and wild-type controls. We demonstrated a neurotropic viral spread into the CNS of after intranasal infection. Although viral load and histological distribution of infected neurons were independent from CXCR3 signaling early after infection, CXCR3-deficient mice cleared HSV-1 more efficiently 14 days after infection. Furthermore, CXCR3 deficiency led to a decreased weight loss in mice after HSV-1 infection. T cell infiltration and microglial activation was prominently reduced by inhibition of CXCR3 signaling. Quantitative PCR of proinflammatory cytokines and chemokines confirmed the reduced neuroinflammatory response in CXCR3-deficient mice during HSE. Our results demonstrate that the recruitment of peripheral immune cells into the CNS, induction of neuroinflammation, and consecutive weight loss during herpes encephalitis is modulated by CXCR3 signaling. Interruption of the CXCR3 pathway ameliorates the detrimental host immune response and in turn, leads paradoxically to an enhanced viral clearance after intranasal infection. Our data gives further insight into the role of CXCR3 during HSE after intranasal infection.

Tubular Occlusion Prevents Water-treeing and Through-and-Through Fluid Movement in a Single-bottle, One-step Self-etch Adhesive Model

Water entrapment occurs at resin-dentin interfaces of one-step self-etch adhesives. We hypothesized that by preventing water fluxes from dentin, any water entrapment would be attributed to incomplete removal of adhesive solvents. We tested this hypothesis by bonding to transparent carious dentin containing occluded dentinal tubules. An experimental single-bottle, one-step self-etch adhesive was applied to flat surfaces of caries-affected dentin surrounded by sound dentin, with or without pulpal pressure. Resin-dentin interfaces were examined with TEM after silver-impregnation. Although caries-affected dentin was highly porous, adhesive layers were devoid of silver deposits when tubules were occluded. Conversely, variable extents of water-treeing and water-droplets were identified from adhesive layers in bonded sound dentin. Water-treeing and water-droplet formation, being manifestations of evaporative and convective water fluxes, can be eliminated during bonding to occluded transparent carious dentin. However, the highly porous nature of this clinically relevant substrate after bonding may lead to potentially undesirable consequences.

T-bet expression by Th cells promotes type 1 inflammation but is dispensable for colitis

The transcription factor T-bet is highly expressed by Th cells isolated from the inflamed intestine of Crohn's disease patients, and has been regarded a critical driver of murine T cell-induced colitis. However, we show here that T-bet expression by Th cells is not required for the manifestation of T-cell-induced colitis in the presence of segmented filamentous bacteria and Helicobacter hepaticus. T-bet expression by Th cells controls their survival and localization, their repertoire of chemokine and chemokine receptor expression, the accumulation of monocytes and macrophages in the inflamed colon, and their differentiation to the M1 type, i.e., type 1 inflammation. Nevertheless, T-bet-deficient Th cells efficiently induce colitis, as reflected by weight loss, diarrhea, and colon histopathology. T-bet-deficient Th cells differentiate into Th1/17 cells, able to express IFN-γ and IL-17A upon restimulation. While neutralization of IL-17A exacerbated colitis induced by wild-type or T-bet-deficient Th cells, neutralization of IFN-γ completely abolished colitis.

Acute myocardial infarction with isolated congenitally corrected transposition of the great arteries

Congenital cardiac abnormalities diagnosed at the time of acute coronary syndrome are rare. A 43-year-old man presented to the emergency department complaining of recurring, severe chest pain. Subsequent emergent coronary angiography demonstrated unusual coronary anatomy: 1) one small caliber bifurcating vessel originating from the right sinus of Valsalva; 2) one very large vessel arising from the posterior sinus; and 3) no coronary artery from the normal left sinus of Valsalva. The large vessel from the posterior sinus was totally occluded in its midportion and was treated with intravascular ultrasound-guided percutaneous coronary intervention. Further diagnostic workup, including two-dimensional transthoracic echocardiogram and computed tomographic coronary angiography, demonstrated isolated corrected transposition of the great arteries with a dilated systemic ventricle and systolic dysfunction with an ejection fraction of 30%. The patient's clinical course was complicated by recurrent nonsustained ventricular tachycardia, treated with medical therapy and a dual-chamber implantable cardioverter defibrillator. This case is an example of a common clinical presentation with a very uncommon congenital heart disorder. Similar cases may become more frequent as the number of adult congenital heart patients increases in the population.