Towards a Better Understanding of Activated Carbon-Based Amendments for In Situ Treatment of Petroleum Hydrocarbons in Anaerobic Groundwater Systems

Injected activated carbon (AC) particulate amendments for the in situ treatment of groundwater impacted by petroleum hydrocarbons (PHCs) is relatively new, and relies on a combination of AC sorption and biodegradation. Currently the performance of this technology remains unclear, primarily related to the long-term interplay between sorption and biodegradation and whether the presence of AC enhances the anaerobic biodegradation of PHCs. To address these uncertainties, this research investigated the sorption and anaerobic biodegradation (sulfate reducing and methanogenic) behaviour in microcosm experiments amended with AC and column experiments designed to mimic an AC permeable reactive barrier (PRB) over a period of 1 to 2 years. The powdered AC (PAC) used in this research (WPC from Calgon Carbon Corporation) had a rough, irregular surface with potential macropore openings of 0.8 ± 0.3 µm, and variable particle sizes with an average diameter of 11.5 ± 4.4 µm. Sorption and desorption equilibrium experiments showed that the magnitude of single-solute (benzene [B], toluene [T], or o-xylene [X]) and multi-solute (BTX combined) sorption or desorption followed X > T > B and B > T > X, respectively. Due to competitive sorption, the magnitude of B, T, and X sorption in the multi-solute system was reduced relative to the single-solute systems. Sorption and desorption equilibrium conditions differed suggestive of hysteresis; however, this behaviour was not fully explored in this research. The best-fit single-solute Freundlich isotherm parameters for benzene, toluene and o-xylene were 36.1 ± 3.8, 0.484 ± 0.045, and 88.2 ± 7.7 for K_(f_i ) ([mg/g][L/mg]n) and 0.421 ± 0.044, 132 ± 20 and 0.371 ± 0.099 for n_(f_i ) (-), respectively. The improved simplified ideal adsorption solution (ISIAS) model was fit to the multi-solute sorption data and the competition factors (ai) were estimated for benzene, toluene and o-xylene as 1.42 ± 0.38, 1.43 ± 0.16 and 1.08 ± 0.08, respectively. Temporal sorption (up to 48 hours) and desorption (up to 720 hours) experiments showed that the time to reach sorption or desorption equilibrium for single-solute benzene and toluene was rapid (≤ 0.5 hours). Single-solute (toluene-only) and multi-solute (BTX) abiotic and bioactive (including sulfate-limited [10-20 mg/L SO42-]) or sulfate amended [138-275 mg/L SO42-]) microcosms with and without PAC were constructed (in addition to starved controls without toluene, BTX or PAC). Aqueous and solid phase toluene or BTX concentrations from the single- and multi-solute PAC amended microcosms, respectively, were compared to the single- and multi-solute Freundlich or ISIAS model predictions. In general, both the single- and multi-solute sorption isotherm models were found to overestimate the measured solid phase concentrations in the microcosms. This disparity is presumably due to differences in mixing conditions and solution matrix chemistry, or competitive sorption by metabolites and biofilm formation in the PAC amended microcosms. In the multi-solute microcosm systems, the observed o-xylene solid phase concentrations deviated the most from the ISIAS model predicted solid concentrations followed by toluene and then benzene. In the subset of single- and multi-solute sulfate-limited bioactive microcosms, evidence of methanogenesis coupled to a background substrate (other than toluene or BTX) was evident from the geochemical (i.e., CH4 production) and molecular (i.e., Methanomethylovorans, Methanosaeta and Methanobacterium enrichment) data. Methane production and methanogenic enrichment were consistently elevated in the bioactive microcosms with PAC, potentially supporting enhanced methanogenesis and archaeal growth in the presence of AC. Contrarily, in the subset of single- and multi-solute sulfate-amended bioactive microcosms, sulfate reduction was coupled to the oxidation of toluene or o-xylene (not benzene, which was recalcitrant) evidenced by the repetitive or preferential biodegradation of toluene followed by o-xylene in the multi-solute microcosm and supported by geochemical (i.e., SO42- reduction, and HS- and total inorganic carbon [TIC] formation) and molecular (i.e., enrichment of sulfate reducing bacteria, including Desulfosporosinus, Desulfoprunum and Desulfobacteraceae) data. In the single- and multi-solute sulfate-amended bioactive microcosms with PAC, the solid phase mass of toluene was repetitively reduced by ≥ 96% showing that PAC regeneration occurred during anaerobic biodegradation. Although anaerobic biodegradation of toluene and o-xylene were repetitively demonstrated, there was no substantial difference in the PHC, geochemical or molecular data collected between the single- or multi-solute sulfate amended bioactive microcosms with and without PAC indicating that the presence of PAC did not influence the anaerobic microbial activity. Additionally, the anaerobic biodegradation rate of toluene was not enhanced in the presence of PAC. Collectively, there were no discernible differences in the anaerobic biodegradation of toluene between the sulfate amended bioactive microcosms with and without PAC over the 1-year monitoring period. Three types of single-solute (toluene-only) and multi-solute (BTX) columns (37 cm long, 3.75 cm inner diameter) were constructed to represent PAC sorption alone, bioactivity alone, and PAC sorption with bioactivity. The columns were operated for approximately 2 years, with Year-1 serving as an acclimation period, and Year-2 used for high-resolution temporal monitoring. For the columns containing PAC, a 6-cm long PAC zone (0.5% wt/wt) was located near the middle of the column to mimic an AC PRB. During Year-2 for the multi-solute column with PAC sorption alone, the change in BTX concentration between the influent and effluent followed X > T > B given that o-xylene has the highest sorption capacity followed by toluene and then benzene. For the single-solute and multi-solute columns with PAC sorption alone the change in toluene concentration between the influent and effluent was greater for the single-solute column relative to the multi-solute column given that the sorption capacity of toluene was reduced in the multi-solute competitive system. For the multi-solute bioactive column without PAC sorption the change in concentration between the influent and effluent followed T > X > B due to the preferential biodegradation of toluene prior to o-xylene and the recalcitrance of benzene (as observed in the microcosm experiments). For the multi-solute bioactive column with PAC sorption the change in concentration between the influent and effluent followed T > X > B due to the preferential biodegradation of toluene and preferential sorption of o-xylene as toluene was biodegraded. The solid phase concentration of toluene within the PAC zone of the single- and multi-solute bioactive columns was highest at the leading edge followed by a gradual reduction towards the end of the PAC zone. The gradient in the solid phase toluene concentration shows that toluene desorbed more due to biodegradation towards the end of the PAC zone, furthest from the influent where toluene was continually replenished. In the bioactive multi-solute column, the magnitude of solid phase BTX concentrations within the PAC zone followed X > T > B at the leading edge; however, directly downgradient the solid phase BTX concentrations within the PAC zone followed X > B > T due to the biodegradation of toluene which resulted in higher sorption of o-xylene and benzene. Using the Year-2 data, an overall column mass balance was estimated by subtracting the cumulative effluent mass from the cumulative mass injected. The single- and multi-solute bioactive columns with PAC sorption yielded the largest removal of toluene mass compared to columns with either only PAC sorption or only bioactivity. For example, among the single-solute columns the mass removal of toluene was greatest for the bioactive column with PAC sorption (99.5% reduction), followed by the column with only PAC sorption (74.6% reduction) and the column with only bioactivity (44.4% reduction). The depletion in effluent toluene mass during Year-2 was consistent between the single- and multi-solute bioactive columns with PAC sorption; however, for the multi-solute column breakthrough of benzene and o-xylene occurred given the recalcitrance of benzene and the competitive inhibition of o-xylene during toluene biodegradation. Anaerobic biodegradation within the single- and multi-solute bioactive columns with or without PAC sorption was supported by changes in geochemical parameters that would be expected under sulfate reducing and methanogenic conditions (i.e., SO42- reduction, and HS-, TIC and CH4 formation). Like the microcosm systems, there was no difference in the magnitude of change of the geochemical parameters between columns with or without PAC, suggesting that the PAC zone in the bioactive columns did not influence the microbial activity. However, the PAC zone did influence the spatial distribution of anaerobic microbes. For the columns with only bioactivity the relative abundance of Methanosarcina and Methanomethylovorans were highest at the influent ends relative to the effluent ends. Whereas, for the bioactive columns with PAC sorption the relative abundance of Methanosaeta, Methanobacterium and Methanosarcina were highest within the PAC zone relative to outside of the PAC zone, in addition to being higher in abundance relative to all bacteria detected within the PAC zone (primarily Desulfosporosinus, Edwardsbacteria and Berkelbacteria). In the multi-solute bioactive column with PAC sorption, the abundance of Desulfosporosinus was also notably elevated at the leading edge of the PAC zones (coinciding with the location of the highest solid phase toluene concentration sorbed to the PAC). Compound specific isotope analysis (CSIA) revealed enrichment of 2H-T in the single- and multi-solute columns with only bioactivity or PAC sorption, although the average value of δ2H-T between the single- and multi-solute columns with only bioactivity was 36.1 ± 8‰ greater than the columns with only PAC sorption, as expected. The magnitude of hydrogen isotope fractionation of toluene associated with a combination of PAC sorption and biodegradation is unknown given toluene was depleted in the bioactive column with PAC sorption. Unlike toluene, a direct comparison of the hydrogen isotope fractionation of o-xylene between the multi-solute columns showed that the average value of δ2H-X was 54‰ and 58‰ greater in the bioactive column with PAC sorption relative to the columns with only PAC sorption or only bioactivity, respectively. 2H-X enrichment in the multi-solute bioactive column with PAC sorption was presumably due to a significant amount of o-xylene sorption to the PAC as toluene was biodegraded as opposed to substantial o-xylene biodegradation (supported by the solid phase data). Collectively the compiled data sets provide comprehensive insight into how AC particulate amendments behave in anaerobic systems in contact with PHCs, and the interplay between BTX sorption and anaerobic biodegradation under sulfate reducing and methanogenic conditions. These data provide direct evidence that the presence of PAC particulate amendments does not enhance the biodegradation of BTX relative to systems with no PAC under sulfate reducing conditions. Instead, the presence of the PAC provides rapid reductions in contaminant concentrations relative to systems without PAC and sustains reductions in the aqueous phase concentration of the most preferentially degraded solute under variable loading conditions as the PAC is regenerated. The PAC also influences microbial activity during PHC biodegradation by promoting microbial growth on the PAC, with notably high methanogenic enrichment. This research also provides evidence that ideal isotherms are not representative of the sorption behaviour in bioactive systems with AC and tend to overestimate sorption. Finally, PAC sorption, most notably for the most preferentially sorbed solute in the multi-solute system, generates substantial hydrogen isotope enrichment which may lead to overestimations in the fractionation presumed to be associated with biodegradation when integrating CSIA into monitoring approaches for bioactive systems with AC

Polymyxins and quinazolines are LSD1/KDM1A inhibitors with unusual structural features

Because of its involvement in the progression of several malignant tumors, the histone lysine-specific demethylase 1 (LSD1) has become a prominent drug target in modern medicinal chemistry research. We report on the discovery of two classes of noncovalent inhibitors displaying unique structural features. The antibiotics polymyxins bind at the entrance of the substrate cleft, where their highly charged cyclic moiety interacts with a cluster of positively charged amino acids. The same site is occupied by quinazoline-based compounds, which were found to inhibit the enzyme through a most peculiar mode because they form a pile of five to seven molecules that obstruct access to the active center. These data significantly indicate unpredictable strategies for the development of epigenetic inhibitors

Clinical and laboratory characterization of patients with localized scleroderma and response to UVA-1 phototherapy: In vivo and in vitro skin models

Background/Purpose Localized scleroderma (LS) is a rare disease leading to progressive hardening and induration of the skin and subcutaneous tissues. LS is responsive to UVA-1 phototherapy, though its exact mechanism of action dermal fibrosis is yet to be fully elucidated. We aimed to investigate the molecular changes induced by UVA-1 rays in human primary fibroblasts cultures. Methods A total of 16 LS patients were treated with medium-dose UVA-1 phototherapy. At baseline, during and after therapy, Localized Scleroderma Assessment Tool, Dermatology Life Quality Index and lesions' staging and mapping were performed along with high-frequency ultrasound (HFUS) examination for dermal thickness assessment. Gene expression analysis for 23 mRNA transcripts, in vitro UVA-1 irradiation and viability tests were realized on lesional fibroblasts' primary cultures, before and 3 months after therapy. Results The dermal thickness, the LoSCAT and the DLQI progressively decreased starting from the last phototherapy session up to the 6 and 9 month follow-ups (-57% and -60%, respectively). Molecular gene analysis (rt-PCR) revealed that UVA-1 phototherapy exerts multiple effects: the activation of specific anti-fibrotic pathways (e.g., overexpression of CTHRC1 and metalloproteases 1, 2, 7, 8, 9, 12, suppression of TIMP-1), the downregulation of peculiar pro-fibrotic pathways (e.g., downregulation of TGF-ss, TGF-ssrII, Grb2, SMAD 2/3, TNRSF12A, CTGF) through a significant overexpression of IL-1ss; the stabilization of collagen synthesis acting on genes COL1A1, COL3A1, COL8A1, COL10A1, COL12A1. Conclusion UVA-1 phototherapy adds significant benefits in local tissue remodeling, rebalancing the alteration between pro-fibrotic and anti-fibrotic pathways; these changes can be well monitored by HFUS. © 2022 The Authors

Endovascular treatment of aortoesophageal and aortobronchial fistulae

none6Background: Even when promptly recognized and treated, aortoesophageal (AEF) and aortobronchial (ABF) fistulae are highly lethal conditions. Open surgical repair also carries a high risk of mortality and morbidity. Several alternative strategies have been recently reported in the literature including thoracic endovascular aortic repair (TEVAR). However, relatively little is known about results of TEVAR for AEF and ABF due to their rarity and the lack of large surveys. Methods: A voluntary national survey was conducted among Italian universities and hospital centers with an endovascular program. Questionnaires were distributed by e-mail to participating centers and aimed to evaluate the results of endovascular repair of established AEF or ABF. Results: Seventeen centers agreed to participate and provided data on their patients. Between 1998 and 2008, a total of 1138 patients were treated with TEVAR. In 25 patients (2.2%), the indication to treatment was an AEF and/or an ABF. In 10 of these cases (40%), an associated open surgical procedure was also performed. Thirty-day mortality rate of AEF/ABF endovascular repair was 28% (7 cases). No cases of paraplegia or stroke were observed. Mean follow-up was 22.6 months (range, 1-62). Actuarial survival at 2 years was 55%. Among the 18 initial survivors, five patients (28%) underwent reintervention due to late TEVAR failure. Conclusions: Stent grafting for AEF and ABF represents a viable option in emergent and urgent settings. However, further esophageal or bronchial repair is necessary in most cases. Despite less invasive attempts, mortality associated with these conditions remains very high. Copyright © 2010 by the Society for Vascular Surgery.Chiesa, R.; Melissano, G.; Marone, E.M.; Kahlberg, A.; Marrocco-Trischitta, M.M.; Tshomba, Y.Chiesa, R.; Melissano, G.; Marone, ENRICO MARIA; Kahlberg, A.; Marrocco Trischitta, M. M.; Tshomba, Y

Optical filter based on a coupled bilayer photonic crystal

We report on the fabrication of an ultra-compact optical filter based on photonic crystal free-standing membranes in bi-layer configuration. The basic heterostructure consists of two 376nm-thick GaAs-membranes sandwiched between air on a GaAs substrate. The air gap between the two membranes is 520nm thick. The normal-incidence reflectance measurements and the numerical simulation of reflection spectra show a high sensitivity to the holes diameter

A Tail-Based Mechanism Drives Nucleosome Demethylation by the LSD2/NPAC Multimeric Complex

Summary: LSD1 and LSD2 are homologous histone demethylases with opposite biological outcomes related to chromatin silencing and transcription elongation, respectively. Unlike LSD1, LSD2 nucleosome-demethylase activity relies on a specific linker peptide from the multidomain protein NPAC. We used single-particle cryoelectron microscopy (cryo-EM), in combination with kinetic and mutational analysis, to analyze the mechanisms underlying the function of the human LSD2/NPAC-linker/nucleosome complex. Weak interactions between LSD2 and DNA enable multiple binding modes for the association of the demethylase to the nucleosome. The demethylase thereby captures mono- and dimethyl Lys4 of the H3 tail to afford histone demethylation. Our studies also establish that the dehydrogenase domain of NPAC serves as a catalytically inert oligomerization module. While LSD1/CoREST forms a nucleosome docking platform at silenced gene promoters, LSD2/NPAC is a multifunctional enzyme complex with flexible linkers, tailored for rapid chromatin modification, in conjunction with the advance of the RNA polymerase on actively transcribed genes. : Through biophysical, biochemical, and structural studies, including cryo-EM, Marabelli et al. describe how NPAC promotes LSD2 productive interaction with the nucleosome in a rapid and flexible manner. Their findings provide a molecular mechanism for LSD2 activity in the context of H3K4me2 demethylation during Pol II transcriptional elongation. Keywords: histone demethylation, cryoelectron microscopy, chromatin reader, flavoenzyme, epigenetics, evolution of protein function, molecular recognitio

Gauge theories as a geometrical issue of a Kaluza-Klein framework

We present a geometrical unification theory in a Kaluza-Klein approach that achieve the geometrization of a generic gauge theory bosonic component. We show how it is possible to derive the gauge charge conservation from the invariance of the model under extra-dimensional translations and to geometrize gauge connections for spinors, thus we can introduce the matter just by free spinorial fields. Then, we present the applications to i)a pentadimensional manifold $V^{4}\otimes S^{1}$, so reproducing the original Kaluza-Klein theory, unless some extensions related to the rule of the scalar field contained in the metric and the introduction of matter by spinors with a phase dependence from the fifth coordinate, ii)a seven-dimensional manifold $V^{4}\otimes S^{1}\otimes S^{2}$, in which we geometrize the electro-weak model by introducing two spinors for any leptonic family and quark generation and a scalar field with two components with opposite hypercharge, responsible of spontaneous symmetry breaking.Comment: 37 pages, no figure

LDL-cholesterol control in the primary prevention of cardiovascular diseases. An expert opinion for clinicians and health professionals

Aims: Although adequate clinical management of patients with hypercholesterolemia without a history of known cardiovascular disease is essential for prevention, these subjects are often disregarded. Furthermore, the scientific literature on primary cardiovascular prevention is not as rich as that on secondary prevention; finally, physicians often lack adequate tools for the effective management of subjects in primary prevention and have to face some unsolved relevant issues. This document aims to discuss and review the evidence available on this topic and provide practical guidance. Data synthesis: Available algorithms and risk charts represent the main tool for the assessment of cardiovascular risk in patients in primary prevention. The accuracy of such an estimate can be substantially improved considering the potential contribution of some additional risk factors (C-reactive protein, lipoprotein(a), family history of cardiovascular disease) and conditions (environmental pollution, sleep quality, socioeconomic status, educational level) whose impact on the cardiovascular risk has been better understood in recent years. The availability of non-invasive procedures to evaluate subclinical atherosclerosis may help to identify subjects needing an earlier intervention. Unveiling the presence of these conditions will improve cardiovascular risk estimation, granting a more appropriate intervention. Conclusions: The accurate assessment of cardiovascular risk in subjects in primary prevention with the use of algorithms and risk charts together with the evaluation of additional factors will allow physicians to approach each patient with personalized strategies, which should translate into an increased adherence to therapy and, as a consequence, a reduced cardiovascular risk