Chemistry and environmental implications of thio-red and 2,4,6-trimercaptotriazine compounds

Many compounds, including Thio-Red® and 2,4,6-trimercaptotriazine, trisodium salt (TMT-55), have been marketed to precipitate mercury and other heavy metals from water, including contaminated ground waters. For the products to be effective, information is needed on the chemistry of the products, how they precipitate metals from aqueous solutions, and the chemistries and stabilities of the precipitates. CS32-, HS-, and S2- are the dominant sulfur species in Thio-Red®. They precipitate heavy metals from water as sulfides (e.g., HgS, PbS, and ZnS). Thio-Red® also contains traces of poisonous carbon disulfide (CS2). Additional CS2 could form from reactions between dissolved heavy metals and CS32-. Large volumes of undiluted Thio-Red® should not be injected into low oxygen environments for in situ restoration until studies eliminate the possibility of contamination from CS2 or H2S. TMT-55 is Na3C3N3S3•9H20. The crystallographic data at 25°C are R3, Z = 6, a= 17.600(1) A, c = 9.720(2) A, V= 2607.5(5) A3, and a density of 1.55 g/cm3• The precipitation of divalent mercury with TMT-55 may produce one or more mercury 2,4,6-trimercaptotriazine (HgTMT) compounds, including white, greenish yellow to greenish brown, gray, or yellow varieties. The white variety probably contains mercury(I). White HgTMT is monoclinic with a= 5.904(3) A, b = 6.966(1) A, c = 4.572(1) A, /3= 104.85(2)0, and V= 181.79 A3. Within three months, white HgTMT may decompose in air or aerated water to the yellow or gray varieties. In batch leachates with distilled and deionized water, white HgTMT may release more than 3 milligrams/liter of mercury. Mercury concentrations in water leachates of gray and bright yellow samples are relatively low (3.3 - 53 micrograms/liter). The gray, yellow and greenish varieties still require extensive chemical analyses and leaching studies to identify any leachable organic compounds. TMT-55 should not be used in the in situ restoration of mercury contaminated sites until the resulting precipitates are known to be stable. Studies ofBalC3N3S3) 2•8H20 and BaHiC3N3S3) 2•4.5H20 (BaTMT compounds) were initiated to determine ifTMT-55 could be used to remove barium from water. However, the aqueous solubilities of both compounds are probably too high (around 5 grams/liter) for effective barium removal. The results of powder XRD analyses show that B(C3N3S3) 2•8H20 is either hexagonal or orthorhombic. The results of a single crystal analysis of BaHiC3N3S3) 2•4.5H20 at 25°C state that the compound is monoclinic (P2/c) with Z = 4, calculated density= 2.077 g/cm3, a= 8.5576(4) A, b = 21.028(1) A, c = 20.276(1) A, /J= 96.440(1)0, and V= 3625.6(3) A3

Archean metamorphism in northwestern Ontario and southeastern Manitoba

Four areas are considered in this study. In Ontario, north-south traverses were made along Highway 599 between Savant Lake and Central Patricia, along the Vermilion River road (40 kilometers northeast of Sioux Lookout) and along Highway 105 between Vermilion Bay and Ear Falls (Fig. 3). The fourth area is centered at Bird River, northeast of Lac du Bonnet, Manitoba. The study areas are located in the Uchi, English River and Wabigoon Subprovinces. The traverse along Highway 599 between Savant Lake and Central Patricia crosses the three subprovinces (Fig. 3). Pelites in the eastern Lake St. Joseph area (Uchi Sub province) and Wabigoon Subprovince indicate that metamorphic conditions were 2-4 kb and 425-600°C (Fig. 3). The Vermilion River logging road crosses the English River Subprovince and has four lithologies that are useful in determining metamorphic conditions: hypersthene ± clinopyroxene granulites, biotite, biotite-garnet, and biotite-garnet-cordierite paragneisses (Fig. 3). Garnet cordierite geobarometry yielded pressures of 3.8-6.S kb. The metamorphic temperatures increased slightly for the four lithologies: biotite gneisses (\u3c610-650°C), biotite-garnet gneisses (610-670°C), and granulites and biotite-garnet cordierite gneisses (650-750°C) . The Red Lake road traverse crosses 3-4 km of the extreme northern Wabigoon Subprovince and approximately 90 km of the English River Subprovince (Fig. 3). The rocks of the North and South Domains of the English River Sub province were probably metamorphosed at 650-750°C and 5-7.5 kb. The Bird River greenstone belt is located approximately 200 km northeast of Winnipeg in the English River Subprovince (Fig. 3, 34). Metamorphic temperatures were usually 450-600°C and were estimated from metamorphic assemblages. The common occurrence of andalusite in the pelites suggests that metamorphic pressures did not exceed 4 kb in most of the belt. Carbonate-rich rnetabasites at the Bird River Bridge may have had Xco2 values that exceeded 0.15. Two tectonic models for the formation of the Uchi, English River, and Wabigoon subprovinces were derived from the pressure and temperature data, along with geophysical and structural information from other studies. A non subduction model assumes that Archean plates were too thin and hot to be subducted (Fig. 43-47). The plate tectonics model includes subducting plates and is based on the work of Langford and Morin (1976) (Fig. 49)

Observations of Peak Strength Behavior in CSA Cement Mortars

The purpose of this study was to assess the mechanical property performance behavior of calcium sulfoaluminate (CSA) cement mortar when cured at ambient laboratory temperature of ~23°C (73°F) and constant 50% relative humidity for an extended period of time. Four CSA cement mortars were tested. Three CSA cement mortars contained equivalent mass amounts of calcium sulfate; whereas, the fourth mortar contained double the amount of calcium sulfate. The three CSA cement mortars containing constant mass amounts of calcium sulfate differed as the specific type of calcium sulfate varied across the three formulations—one mortar containing solely anhydrite, one mortar contained half anhydrite and half gypsum while the other mortar solely contained gypsum. The fourth mortar contained double the amount of calcium sulfate when compared with the others while having a 1/1 blend of anhydrite and gypsum. Specific mortars were either tested for direct tensile strength according to ASTM C307 or for compressive strength according to ASTM C109. All tested mortars displayed statistically significant strength loss trends versus time when cured at constant 50% relative humidity. Cement paste samples were analyzed with TGA/SDT and XRD in an effort to identify microstructure changes corresponding to observed strength loss. Cement paste analysis suggests strength loss within the tested CSA cement mortars occurred as a result of ettringite decomposition

Notes on the Potential for the Concentration of Rare Earth Elements and Yttrium in Coal Combustion Fly Ash

Certain Central Appalachian coals, most notably the Fire Clay coal with a REY-enriched volcanic ash fall tonstein, are known to be enriched in rare earth elements. The Fire Clay tonstein has a greater contribution to the total coal + parting REY than would be inferred from its thickness, accounting for about 20%–35% of the REY in the coal + parting sequence. Underground mining, in particular, might include roof and floor rock and the within-seam partings in the mined product. Beneficiation, necessary to meet utility specifications, will remove some of the REY from the delivered product. In at least one previously published example, even though the tonstein was not present in the Fire Clay coal, the coal was enriched in REY. In this case, as well as mines that ship run-of-mine products to the utility, the shipped REY content should be virtually the same as for the mined coal. At the power plant, however, the delivered coal will be pulverized, generally accompanied by the elimination of some of the harder rock, before it is fired into the boiler. Overall, there are a wide range of variables between the geologic sample at the mine and the power plant, any or all of which could impact the concentration of REY or other critical materials in the coal combustion products

Attenuation of Experimental Aortic Aneurysm Formation in P-Selectin Knockout Mice

The aim of this study was to determine the role of P-selectin, an adhesion molecule found on the surface of activated platelets and endothelial cells during experimental aortic aneurysm formation. Infrarenal abdominal aortas of C57 black wild-type (WT) mice and P-selectin knockout (PKO) mice were measured in situ and then perfused with porcine pancreatic elastase (0.332 U mL). Whole blood was drawn from the tail artery on day 2 pre-perfusion to determine total and differential white blood cell (WBC) counts. On day 14 postperfusion, aortic diameters (AD) of WT mice ( N 19) and PKO mice ( N 9) were measured. An aortic aneurysm was defined as a 100 or greater increase in AD from pre-perfusion measurement. Immunohistochemistry, including H&E, trichrome and von Gieson staining, was performed on harvested aortic tissue. Statistical analysis was performed by t -test and Fisher's exact test. There were no significant differences in peripheral leukocyte counts at baseline between the two groups. WT mice had significantly larger AD compared to PKO mice at day 14 postperfusion (116 vs. 38 , P < 0.001). Aortic aneurysm penetrance was 52 in WT mice, while 0 ( P 0.01) of PKO mice formed aneurysms. On histologic examination, WT mouse aortas were associated with a significant inflammatory response and degradation of elastin and collagen fibers, while PKO mouse aortas lacked signs of inflammation or vessel wall injury. P-selectin deficiency attenuates aneurysm formation in the elastase aortic perfusion model. This was associated with a blunting of the inflammatory response and preserved vessel wall intergrity following elastase perfusion in the P-selectin knockout mice. Further investigation to elucidate the independent contributions of endothelial cell and platelet P-selectin in experimental aortic aneurysm formation is required.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73125/1/annals.1383.014.pd

Gas emissions, minerals, and tars associated with three coal fires, Powder River Basin, USA.

Ground-based surveys of three coal fires and airborne surveys of two of the fires were conducted near Sheridan, Wyoming. The fires occur in natural outcrops and in abandoned mines, all containing Paleocene-age subbituminous coals. Diffuse (carbon dioxide (CO(2)) only) and vent (CO(2), carbon monoxide (CO), methane, hydrogen sulfide (H(2)S), and elemental mercury) emission estimates were made for each of the fires. Additionally, gas samples were collected for volatile organic compound (VOC) analysis and showed a large range in variation between vents. The fires produce locally dangerous levels of CO, CO(2), H(2)S, and benzene, among other gases. At one fire in an abandoned coal mine, trends in gas and tar composition followed a change in topography. Total CO(2) fluxes for the fires from airborne, ground-based, and rate of fire advancement estimates ranged from 0.9 to 780mg/s/m(2) and are comparable to other coal fires worldwide. Samples of tar and coal-fire minerals collected from the mouth of vents provided insight into the behavior and formation of the coal fires

Clinical outcomes of patients with unresectable primary liver cancer treated with yttrium-90 radioembolization with an escalated dose

PURPOSE: Yttrium-90 (90Y) radioembolization with an escalated dose has been shown to improve clinical outcomes compared with standard dose radioembolization, but there are few data on the local control of primary liver tumors. We reported the clinical outcomes of patients with unresectable primary liver tumors treated with 90Y radioembolization with an escalated dose. METHODS AND MATERIALS: Clinical data of patients with unresectable hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and biphenotypic tumors (cHCC-CC) treated with radioembolization with an escalated dose (≥150 Gy) between 2013 and 2020 with \u3e3 months follow-up were retrospectively reviewed. The primary endpoint was freedom from local progression. Clinical response was defined by Modified Response Evaluation Criteria in Solid Tumours and toxic effects were assessed using Common Terminology Criteria for Adverse Events version 5.0. RESULTS: Fifty-three patients with HCC and 15 patients with CC/cHCC-CC were analyzed. The median dose delivered was 205 Gy (interquartile range, 183-253 Gy) and 198 Gy (interquartile range, 154-234 Gy) for patients with HCC and CC/cHCC-CC, respectively. The 1-year freedom from local progression rate was 54% (95% confidence interval [CI], 38%-78%) for patients with HCC and 66% (95% CI, 42%-100%) for patients with CC/cHCC-CC. For patients with HCC, United Network for Organ Sharing nodal stage 1 ( CONCLUSIONS: Treatment of unresectable primary liver tumors with 90Y radioembolization with an escalated dose was safe and well tolerated. Delivery of \u3e268 Gy may improve local tumor control of HCC. Determination of the maximum tolerated dose needs to be performed in the context of future prospective dose-escalation trials to further evaluate the safety and efficacy of such an approach

The Nitric Oxide Donor DETA-NONOate Decreases Matrix Metalloproteinase-9 Expression and Activity in Rat Aortic Smooth Muscle and Abdominal Aortic Explants

Our objective was to examine the role of an exogenous nitric oxide (NO) donor, DETA-NONOate (DETA), on matrix metalloproteinase (MMP)-9, MMP-2, and tissue inhibitor of matrix metalloproteinases (TIMP)-1 expression and activity in interleukin (IL)-1β-induced rat aortic smooth muscle cells (RA-SMCs) and rat aortic explants (RAEs). RA-SMCs were incubated with IL-1β (2 ng/ml), an inflammatory cytokine known to induce MMP-9 expression, and increasing concentrations of DETA (0, 1.0, 10, 100 μM; n = 3/group) for 48 hr. RAEs were incubated with IL-1β (2 ng/mL) and increasing concentrations of DETA (0, 5.0, 50, 100, and 500 μM; n = 3/group) for 48 hr. Media were collected and assayed for NO x by the Griess reaction and MMP-9 activity by zymography. Messenger RNA (mRNA) was extracted from cells and analyzed for MMP-9, MMP-2, and TIMP-1 expression levels by quantitative real-time reverse-transcriptase polymerase chain reaction. All statistical analyses were performed by analysis of variance. In RA-SMCs and RAEs, DETA administration resulted in a dose-dependent increase in media NO x concentration (RA-SCM p < 0.01, RAE p < 0.01) and a concurrent decrease in both MMP-9 expression (RASMC p = 0.01, RAE p = 0.01) and activity (RASMC p = 0.04, RAE p = 0.006). There were no significant differences seen in MMP-2 and TIMP-1 expression or activity in response to DETA exposure. DETA decreased IL-1β-induced MMP-9 expression and activity in both RA-SMCs and RAEs in a dose-dependent fashion. In addition, DETA administration had no effect on MMP-2 or TIMP-1 expression or activity in vitro. These data suggest that NO donors may be beneficial in decreasing MMP-9 levels and might serve to inhibit MMP-9-dependent vessel wall remodeling seen during abdominal aortic aneurysm formation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41371/1/10016_2005_Article_9429.pd