752 research outputs found

    Potential impact of northern resource development on aquatic biota: toxicity of chromium and rare earth element processing reagent

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    Chromite and rare earth element development was identified in the 2015 Canadian Federal budget as a significant opportunity, however, key data gaps exist regarding the environmental concerns related to these resource developments. Chromium is essential in the production of stainless steel, and no suitable substitute is known. Rare earth elements (REEs) are a series of metals that are composed of 15 lanthanides, as well as scandium and yttrium. Uses for REEs range from electronic devices (i.e. cell phones, computers, televisions) to magnets and controlling nuclear reactors. While commercial production of REEs signify a great economic opportunity for Canada, key data gaps regarding chemicals involved in processing REEs has been identified. The first objective of this study was to determine the acute toxicity of hexavalent chromium (Cr (VI)) to the invertebrate species Hyalella azteca and to identify the potential mitigating influences of cations and dissolved organic matter (DOM). The second objective was to evaluate the acute toxicity of flotation reagent AERO 6493, conduct toxicity identification/reduction studies, and test REE processing wastewater toxicity to H. azteca and Daphnia magna. Standard methods were followed for both 48 h (D. magna) and 96 h (H. azteca) acute toxicity tests, in media with pH 7.3 and water hardness of 120 mg CaCO3 /L (D. magna) and 60 mg CaCO3 /L (H. azteca) for both objectives. For objective 1, effect of altering water chemistry on Cr (VI) toxicity to H. azteca was tested with additions of Ca (0.5-3.5mM), Na (0.5-3 mM), Mg (0.13-0.64mM), as well as additions of natural sources of DOC (from Pickle Lake and Luther Marsh) at concentrations of 5 and 12 mg DOC/L. No protective effect was observed with additions of Na+, Pickle Lake and 2016 Luther Marsh DOC sources, but a significant protective effect was observed for 2015 Luther Marsh DOC, elevated Mg2+ and Ca2+ concentrations. For objective 2, LC50 was calculated based on survival/mortality for H. azteca (2.6 E-16 % dilution of parent AERO 6493 compound for fresh, 3.9 E-18 % for aged) and immobilization for D. magna (2.0E-5 %). Acute REE processing wastewater toxicity was also calculated for H. azteca (2.44%) and D. magna (23.35%). Studies conducted to determine acute toxicity of Cr (VI) to H. azteca not only lead to an improved understanding of site-specific Cr (VI) toxicity, but also may help to improve the water quality guidelines for protection of aquatic life. As for the toxicity of REE processing reagent AERO 6493, dilutions anticipating the worst possible scenario was tested to invertebrate species. Calculated LC50s and EC50s of parent AERO 6493 and wastewater will help develop a better understanding of toxicity of chemicals incorporated in REE processing, as well as potential suggestions for risk assessment and remediation steps

    Potential impact of northern resource development on aquatic biota: toxicity of chromium and rare earth element processing reagent

    Get PDF
    Chromite and rare earth element development was identified in the 2015 Canadian Federal budget as a significant opportunity, however, key data gaps exist regarding the environmental concerns related to these resource developments. Chromium is essential in the production of stainless steel, and no suitable substitute is known. Rare earth elements (REEs) are a series of metals that are composed of 15 lanthanides, as well as scandium and yttrium. Uses for REEs range from electronic devices (i.e. cell phones, computers, televisions) to magnets and controlling nuclear reactors. While commercial production of REEs signify a great economic opportunity for Canada, key data gaps regarding chemicals involved in processing REEs has been identified. The first objective of this study was to determine the acute toxicity of hexavalent chromium (Cr (VI)) to the invertebrate species Hyalella azteca and to identify the potential mitigating influences of cations and dissolved organic matter (DOM). The second objective was to evaluate the acute toxicity of flotation reagent AERO 6493, conduct toxicity identification/reduction studies, and test REE processing wastewater toxicity to H. azteca and Daphnia magna. Standard methods were followed for both 48 h (D. magna) and 96 h (H. azteca) acute toxicity tests, in media with pH 7.3 and water hardness of 120 mg CaCO3 /L (D. magna) and 60 mg CaCO3 /L (H. azteca) for both objectives. For objective 1, effect of altering water chemistry on Cr (VI) toxicity to H. azteca was tested with additions of Ca (0.5-3.5mM), Na (0.5-3 mM), Mg (0.13-0.64mM), as well as additions of natural sources of DOC (from Pickle Lake and Luther Marsh) at concentrations of 5 and 12 mg DOC/L. No protective effect was observed with additions of Na+, Pickle Lake and 2016 Luther Marsh DOC sources, but a significant protective effect was observed for 2015 Luther Marsh DOC, elevated Mg2+ and Ca2+ concentrations. For objective 2, LC50 was calculated based on survival/mortality for H. azteca (2.6 E-16 % dilution of parent AERO 6493 compound for fresh, 3.9 E-18 % for aged) and immobilization for D. magna (2.0E-5 %). Acute REE processing wastewater toxicity was also calculated for H. azteca (2.44%) and D. magna (23.35%). Studies conducted to determine acute toxicity of Cr (VI) to H. azteca not only lead to an improved understanding of site-specific Cr (VI) toxicity, but also may help to improve the water quality guidelines for protection of aquatic life. As for the toxicity of REE processing reagent AERO 6493, dilutions anticipating the worst possible scenario was tested to invertebrate species. Calculated LC50s and EC50s of parent AERO 6493 and wastewater will help develop a better understanding of toxicity of chemicals incorporated in REE processing, as well as potential suggestions for risk assessment and remediation steps

    Interaction of Apoptotic Cells with Macrophages Upregulates COX-2/PGE 2

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    Recognition of apoptotic cells by macrophages is crucial for resolution of inflammation, immune tolerance, and tissue repair. Cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) and hepatocyte growth factor (HGF) play important roles in the tissue repair process. We investigated the characteristics of macrophage COX-2 and PGE2 expression mediated by apoptotic cells and then determined how macrophages exposed to apoptotic cells in vitro and in vivo orchestrate the interaction between COX-2/PGE2 and HGF signaling pathways. Exposure of RAW 264.7 cells and primary peritoneal macrophages to apoptotic cells resulted in induction of COX-2 and PGE2. The COX-2 inhibitor NS-398 suppressed apoptotic cell-induced PGE2 production. Both NS-398 and COX-2-siRNA, as well as the PGE2 receptor EP2 antagonist, blocked HGF expression in response to apoptotic cells. In addition, the HGF receptor antagonist suppressed increases in COX-2 and PGE2 induction. The in vivo relevance of the interaction between the COX-2/PGE2 and HGF pathways through a positive feedback loop was shown in cultured alveolar macrophages following in vivo exposure of bleomycin-stimulated lungs to apoptotic cells. Our results demonstrate that upregulation of the COX-2/PGE2 and HGF in macrophages following exposure to apoptotic cells represents a mechanism for mediating the anti-inflammatory and antifibrotic consequences of apoptotic cell recognition

    The Effect of Negative CSR Information by Luxury Fashion Brands on Consumer Response

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    Contrary to positive corporate social responsibility (CSR) activities by luxury fashion brands in western countries, little attention has been paid by the same companies to Korean society (FSS, 2012). South Korea is poised to be the next luxury power house in Asia, even overtaking Japan (Luxe Brand Advisors, 2012). Are Korean consumers not as sensitive as western consumers about CSR by luxury fashion brands? To answer these questions, this study explores the effect of negative CSR information by luxury fashion companies on consumer responses

    The origin of proinflammatory cytokines in patients with idiopathic dilated cardiomyopathy.

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    Proinflammatory cytokines and their receptors are increased in the peripheral blood of patients with heart failure. We measured cytokines and their receptors in systemic artery (SA), coronary sinus (CS) and infra-renal inferior vena cava (IVC), in order to investigate their origin and influential factors. Thirty patients with idiopathic dilated cardiomyopathy were performed echocardiography at admission, and right heart catheterization after stabilization. Blood was drawn from 3 sites for measurement of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and soluble tumor necrosis factor-alpha receptor (sTNFR) I, II. TNF-alpha at CS (3.25 +/- 0.34 pg/mL) was higher than those of SA (1.81 +/- 0.39 pg/mL) and IVC (1.88 +/- 0.38 pg/mL, p<0.05). IL-6 at CS (18.3 +/- 3.8 pg/mL) was higher than that of SA (5.8 +/- 1.2 pg/mL, p<0.01). The levels of sTNFR I, II showed increasing tendency in sequence of SA, IVC and CS. TNF-alpha and sTNFR I, II from all sites were proportional to worsening of functional classes at admission (p<0.05). E/Ea by Doppler study at admission, which reflects left ventricular end-diastolic pressure (LVEDP) was positively correlated with TNF-alpha from SA (R=0.71, p<0.01), CS (R=0.52, p<0.05) and IVC (R=0.46, p<0.05). Thus, elevated LVEDP during decompensation might cause cytokine release from myocardium in patients with idiopathic dilated cardiomyopathy

    The Usefulness of Maximum Standardized Uptake Value at the Delayed Phase of Tc-99m sestamibi single-photon emission computed tomography/computed tomography for Identification of Parathyroid Adenoma and Hyperplasia

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    Tc-99m sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has been used to help surgeons explore the location of parathyroid diseases, but quantitative parameters have not been systemically investigated for this purpose. We aimed to establish objective criteria for adenoma and hyperplasia using the standardized uptake value (SUV) in patients with hyperparathyroidism. Thirty-nine hyperparathyroid patients (male/female: 17/22, age: 58.33 +/- 11.69 years) with at least 1 uptake-positive lesion of any degree by visual assessment in preoperative Tc-99m sestamibi quantitative SPECT/CT were included from Oct 2015 to Oct 2017. Pathologically, 44 lesions (32 adenomas and 12 hyperplasia) were identified. All patients experienced normalized levels of intact parathyroid hormone immediately after surgery. Quantitative SPECT/CT was performed at 10 minute and 2 hour post injection of Tc-99m sestabmibi (dose = 740 MBq), and maximum SUV (SUVmax) was measured for the parathyroid lesions. Experienced pathologists evaluated the percentage cellular proportions of chief cells, oxyphil cells, and clear cells. SUVmax (g/mL) of adenomas, hyperplasia, and reference thyroid tissue were 12.92 +/- 6.68, 7.90 +/- 5.49, and 7.01 +/- 2.62 at 10min (early phase), decreasing to 7.46 +/- 5.66, 4.65 +/- 3.14, and 2.21 +/- 1.07 at 2 hour (delayed phase), respectively. The adenomas showed significantly higher SUVmax than both the hyperplasia (P = .0131) and reference thyroid tissue (P &lt; .0001) along the early and delayed phases, but the SUVmax of the hyperplasia did not differ from that of the reference thyroid tissue (P = .4196). The adenomas and hyperplasia were discriminated from the reference thyroid tissue using a cutoff SUVmax of 3.26 at the delayed phase. The adenomas had lower %proportions of oxyphil cells than the hyperplasia (P = .0054), but its SUVmax at the delayed phase was positively correlated with the %proportions of mitochondria-abundant oxyphil cells (rho = 0.418,P = .0173). The hyperplasia showed no correlation between SUVmax and cellular proportions. SUVmax at the delayed phase in the Tc-99m sestamibi quantitative SPECT/CT was useful for the identification and differentiation of parathyroid lesions causing hyperparathyroidism.Y

    Clinical Applications of the Microbiome in Obstetrics

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    Human microbiome refers to the genetic material of approximately 1013 microorganisms present in the human body. These microbiomes interact significantly with the physiological, metabolic, and immune systems, particularly during pregnancy. Microbiome dysbiosis in pregnant women and their fetuses is associated with obstetric complications and poor neonatal outcomes. Oral and gut microbiomes can influence the placenta, uterus, and fetus via hematogenous translocation. Through ascending translocation, vaginal microbiota can directly affect the uterine environment. Current research focuses on the presence of the placental microbiome, which is characterized by low biomass. However, more well-controlled studies are required to specifically address the contamination issues. Use of antibiotics during pregnancy and the mode of delivery, specifically cesarean section, have been linked to the establishment of the neonatal gut microbiome. Probiotic supplementation may be beneficial during pregnancy, particularly for women receiving antibiotic treatment
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