Risk assessment of manganese: A comparison of oral and inhalation derivations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poirier, K.A.; Velazquez, S.F.

1991-03-11

An oral and inhalation human exposure-response risk assessment was calculated for manganese (Mn) using USEPA methodologies for both oral reference dose (RfD) and inhalation reference concentration (RfC) determination. When ingested, Mn is among the least toxic of the essential trace elements. The RfD for Mn is based on ingestion data from normal human diets, balance studies and neurotoxicity resulting from drinking contaminated well water. From these data, a NOAEL of 0.14 mg/kb/day was estimated. Since the NOAEL was thought to account for human sensitivity and Mn is an essential element required for normal human growth, an uncertainty factor (UF) ofmore » 1 was used resulting in a RfD of 1E-1 mg/kg/day. Although neurotoxic effects are rarely observed from oral exposures, they are more commonly associated with exposure to Mn by inhalation. Toxicity from inhaled Mn results in an increased prevalence of respiratory symptoms, reproductive dysfunction and psychomotor disturbances that can ultimately be expressed in a frank effect of manganism characterized by Parkinson disease-like symptoms. Using data from occupational exposure to in organic Mn, a dose duration adjusted LOAEL of 0.34 mg/m{sup 3} is identified. Application of an UF of 300 results in an RfC of 4E-4 mg/m{sup 3}. The RfD and RfC analyses demonstrate a dichotomous data set of toxicological effects dependent upon the route of exposure to Mn. Furthermore, these analyses demonstrate the unique issues of characterizing toxicological risk assessment for essential trace elements.« less

Cross-sections for (p,x) reactions on natural chromium for the production of 52,52m,54Mn radioisotopes

DOE PAGES

Wooten, A. Lake; Lewis, Benjamin C.; Lapi, Suzanne E.

2014-12-11

The production of positron-emitting isotopes of manganese is potentially important for developing contrast agents for dual-modality positron emission tomography and magnetic resonance (PET/MR) imaging, as well as for in vivo imaging of the biodistribution and toxicity of manganese. Furthermore, the decay properties of 52Mn make it an excellent candidate for these applications, and it can easily be produced by bombardment of a chromium target with protons or deuterons from a low-energy biomedical cyclotron. There are several parameters essential to this mode of production—target thickness, beam energy, beam current, and bombardment time—depend heavily on the availability of reliable, reproducible cross-section data.more » Our paper contributes to the routine production of 52gMn for biomedical research by contributing experimental cross-sections for natural chromium ( natCr) targets for the natCr(p,x) 52gMn reaction, as well as for the production of the radiocontaminants 52m, 54Mn.« less

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Lithium manganese oxide (LiMn204... Specific Chemical Substances § 721.4587 Lithium manganese oxide (LiMn204) (generic name). (a) Chemical... as lithium manganese oxide (LiMn204) (P-96-175) is subject to reporting under this section for the...

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Lithium manganese oxide (LiMn204... Specific Chemical Substances § 721.4587 Lithium manganese oxide (LiMn204) (generic name). (a) Chemical... as lithium manganese oxide (LiMn204) (P-96-175) is subject to reporting under this section for the...

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Lithium manganese oxide (LiMn204... Specific Chemical Substances § 721.4587 Lithium manganese oxide (LiMn204) (generic name). (a) Chemical... as lithium manganese oxide (LiMn204) (P-96-175) is subject to reporting under this section for the...

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lithium manganese oxide (LiMn204... Specific Chemical Substances § 721.4587 Lithium manganese oxide (LiMn204) (generic name). (a) Chemical... as lithium manganese oxide (LiMn204) (P-96-175) is subject to reporting under this section for the...

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lithium manganese oxide (LiMn204... Specific Chemical Substances § 721.4587 Lithium manganese oxide (LiMn204) (generic name). (a) Chemical... as lithium manganese oxide (LiMn204) (P-96-175) is subject to reporting under this section for the...

Control of Manganese Dioxide Particles Resulting From In Situ Chemical Oxidation Using Permanganate

DTIC Science & Technology

2008-09-01

Study Description Impacts of MnO2 Reference Field evaluation: A 5-spot recirculation network was employed to deliver 3000 mg/L NaMnO4 to treat up...that affect particle interactions. It may (1) act as a coagulant, facilitating MnO2 aggregation and deposition, (2) convert to other iron hydroxide ...chemical characteristics of the porous media, including pHpzc, zeta potential, particle size (average and distribution), and mineralogy , dictate the extent

Aqueous synthesis of Ag and Mn co-doped In2S3/ZnS quantum dots with tunable emission for dual-modal targeted imaging.

PubMed

Lai, Pei-Yu; Huang, Chih-Ching; Chou, Tzung-Han; Ou, Keng-Liang; Chang, Jia-Yaw

2017-03-01

Here, we present the microwave-assisted synthesis of In 2 S 3 /ZnS core/shell quantum dots (QDs) co-doped with Ag + and Mn 2+ (referred to as AgMn:In 2 S 3 /ZnS). Ag + altered the optical properties of the host QDs, whereas the spin magnetic moment (S=5/2) of Mn 2+ efficiently induced the longitudinal relaxation of water protons. To the best of our knowledge, this is the first report of the aqueous synthesis of color-tunable AgMn:In 2 S 3 /ZnS core/shell QDs with magnetic properties. The synthetic procedure is rapid, facile, reproducible, and scalable. The obtained QDs offered a satisfactory quantum yield (45%), high longitudinal relaxivity (6.84s -1 mM -1 ), and robust photostability. In addition, they exhibited excellent stability over a wide pH range (5-12) and high ionic strength (0.15-2.0M NaCl). As seen by confocal microscopy and magnetic resonance imaging, AgMn:In 2 S 3 /ZnS conjugated to hyaluronic acid (referred to as AgMn:In 2 S 3 /ZnS@HA) efficiently and specifically targeted cluster determinant 44, a receptor overexpressed on cancer cells. Moreover, AgMn:In 2 S 3 /ZnS@HA showed negligible cytotoxicity in vitro and in vivo, rendering it a promising diagnostic probe for dual-modal imaging in clinical applications. In this manuscript, we reported a facial and rapid method to prepare In 2 S 3 /ZnS core/shell quantum dots (QDs) co-doped with Ag + and Mn 2+ (referred to as AgMn:In 2 S 3 /ZnS). Ag + dopants were used to alter the optical properties of the In 2 S 3 host, whereas Mn 2+ co-dopants with their unpaired electrons provided paramagnetic properties. The emission wavelength of the core/shell QDs could be tuned from 550 to 743nm with a maximum PL quantum yield of 45%. The resulting core/shell QDs also maintained a stable emission in aqueous solution at broad ranges of pH (5-12) and ionic strength (0.15-2.0M NaCl), as well as a high photostability under continuous irradiation. In vivo cytotoxicity experiments showed that up to 500μg/mL AgMn:In 2 S 3 /ZnS@HA did not cause obvious toxicity to zebrafish embryos. In vitro targeted cell luminescence and magnetic resonance imaging showed that AgMn:In 2 S 3 /ZnS conjugated to hyaluronic acid was selectively and efficiently internalized in CD44-expressing tumor cells, confirming that the resultant QDs could function as dual-modal imaging probes for accurate diagnosis. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mesopontine median raphe regulates hippocampal ripple oscillation and memory consolidation.

PubMed

Wang, Dong V; Yau, Hau-Jie; Broker, Carl J; Tsou, Jen-Hui; Bonci, Antonello; Ikemoto, Satoshi

2015-05-01

Sharp wave-associated field oscillations (∼200 Hz) of the hippocampus, referred to as ripples, are believed to be important for consolidation of explicit memory. Little is known about how ripples are regulated by other brain regions. We found that the median raphe region (MnR) is important for regulating hippocampal ripple activity and memory consolidation. We performed in vivo simultaneous recording in the MnR and hippocampus of mice and found that, when a group of MnR neurons was active, ripples were absent. Consistently, optogenetic stimulation of MnR neurons suppressed ripple activity and inhibition of these neurons increased ripple activity. Notably, using a fear conditioning procedure, we found that photostimulation of MnR neurons interfered with memory consolidation. Our results demonstrate a critical role of the MnR in regulating ripples and memory consolidation.

Mesopontine median raphe regulates hippocampal ripple oscillation and memory consolidation

PubMed Central

Wang, Dong V.; Yau, Hau-Jie; Broker, Carl J.; Tsou, Jen-Hui; Bonci, Antonello; Ikemoto, Satoshi

2015-01-01

Sharp-wave associated field-oscillations (~200 Hz) of the hippocampus, referred to as “ripples”, are believed to be important for consolidation of explicit memory. Little is known about how ripples are regulated by other brain regions. Here we show that the median raphe region (MnR) plays a key role in regulating hippocampal ripple activity and memory consolidation. We performed in vivo simultaneous recording in the MnR and hippocampus, and found that when a group of MnR neurons were active, ripples were absent. Consistently, optogenetic stimulation of MnR neurons suppressed ripple activity, while inhibition of these neurons increased ripple activity. Importantly, using a fear conditioning procedure, we provided evidence that photostimulation of MnR neurons interfered with memory consolidation. Our results demonstrate a critical role of the MnR in regulating ripples and memory consolidation. PMID:25867120

Role of manganese oxides in the exposure of mute swans (Cygnus olor) to Pb and other elements in the Chesapeake Bay, USA

USGS Publications Warehouse

Beyer, W.N.; Day, D.

2004-01-01

The aims of this study are to estimate exposure of waterfowl to elements in contaminated sediments in the Chesapeake Bay and to consider the potential role of Mn in influencing bioavailability and exposure. Mute swans living on the Aberdeen Proving Ground were collected and samples of swan digesta were analyzed and compared to samples of feces collected from mute swans living at a nearby reference site. Sediments from the proving ground had elevated concentrations of Cu, S, Se, Zn, As, Co, Cr, Hg and Pb, but concentrations of only the first four of these elements were elevated in swan digesta. Sediments from the proving ground had an elevated mean concentration of total As, about seven times the concentration at the reference site, but the swans from that site were not ingesting more As than were reference swans. Swans at both sites were feeding on submerged aquatic vegetation and ingested about 4% sediment at the proving ground and about 5% sediment at the reference site. None of the concentrations detected in the digesta or livers of the swans was considered toxic, although the concentrations of Cu and Se were high compared to those concentrations reported in other waterfowl. A remarkably high mean concentration of Mn (6900 mg/kg, dry weight) detected in the feces of the reference swans was attributed to the deposition of manganese oxides on vegetation. The ingestion of Pb by swans at the reference site was correlated with Mn and Fe concentrations, rather than with markers of sediment ingestion. The Pb was presumably scavenged by Mn and Fe oxides from the water and deposited on the surface of vegetation. Under some environmental chemical conditions, this route of exposure for Pb is more important than sediment ingestion, which was previously thought to be the main route of exposure.

Influence of depositional environment in fossil teeth: a micro-XRF and XAFS study

NASA Astrophysics Data System (ADS)

Zougrou, I. M.; Katsikini, M.; Pinakidou, F.; Papadopoulou, L.; Tsoukala, E.; Paloura, E. C.

2014-04-01

The formation of metal-rich phases during the fossilization of vertebrate fossil teeth, recovered from various deposition environments in northern Greece, is studied by means of synchrotron radiation X-ray fluorescence (SR-XRF) as well as Fe and Mn K edge X-ray absorption fine structure (XAFS) spectroscopy. XRF line-scans from the samples' cross-sections revealed different contamination paths for Mn and Fe. The two-dimensional XRF maps illustrate the spatial distribution of P, Ca, Mn and Fe as well as the precipitation of Fe-rich phases in cementum, dentin and dentinal tubules. Goethite, lepidocrocite and ferrihydrite were detected in the samples' cross-section by means of Fe K edge EXAFS spectroscopy. Moreover the Fe and Mn K edge EXAFS revealed the presence of vivianite and birnessite (MnO2) on the external surface of two samples.

Spin resolved photoelectron spectroscopy of [Mn6IIICrIII]3 + single-molecule magnets and of manganese compounds as reference layers

NASA Astrophysics Data System (ADS)

Helmstedt, Andreas; Müller, Norbert; Gryzia, Aaron; Dohmeier, Niklas; Brechling, Armin; Sacher, Marc D.; Heinzmann, Ulrich; Hoeke, Veronika; Krickemeyer, Erich; Glaser, Thorsten; Bouvron, Samuel; Fonin, Mikhail; Neumann, Manfred

2011-07-01

Properties of the manganese-based single-molecule magnet [\\mathbf {Mn}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}_{\\mathbf {6}} \\mathbf {Cr}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}]^{\\mathbf {3} \\boldsymbol {+}} are studied. It contains six MnIII ions arranged in two bowl-shaped trinuclear triplesalen building blocks linked by a hexacyanochromate and exhibits a large spin ground state of St = 21/2. The dominant structures in the electron emission spectra of [\\mathbf {Mn}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}_{\\mathbf {6}}\\mathbf {Cr}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}]^{\\mathbf {3} \\boldsymbol {+}} resonantly excited at the L3-edge are the L3M2, 3M2, 3, L3M2, 3V and L3VV Auger emission groups following the decay of the primary p3/2 core hole state. Significant differences of the Auger spectra from intact and degraded [\\mathbf {Mn}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}_{\\mathbf {6}}\\mathbf {Cr}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}]^{\\mathbf {3} \\boldsymbol {+}} show up. First measurements of the electron spin polarization in the L3M2, 3V and L3VV Auger emission peaks from the manganese constituents in [\\mathbf {Mn}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}_{\\mathbf {6}} \\mathbf {Cr}^{\\mathbf {I}\\mathbf {I}\\mathbf {I}}]^{\\mathbf {3} \\boldsymbol {+}} resonantly excited at the L3-edge near 640 eV by circularly polarized synchrotron radiation are reported. In addition spin resolved Auger electron spectra of the reference substances MnO, Mn2O3 and MnII(acetate)2·4H2O are given. The applicability of spin resolved electron spectroscopy for characterizing magnetic states of constituent atoms compared to magnetic circular dichroism (MCD) is verified: the spin polarization obtained from MnII(acetate)2·4H2O at room temperature in the paramagnetic state compares to the MCD asymmetry revealed for a star-shaped molecule with a Mn4IIO6 core at 5 K in an external magnetic field of 5 T.

Estimating Air-Manganese Exposures in Two Ohio Towns ...

EPA Pesticide Factsheets

Manganese (Mn), a nutrient required for normal metabolic function, is also a persistent air pollutant and a known neurotoxin at high concentrations. Elevated exposures can result in a number of motor and cognitive deficits. Quantifying chronic personal exposures in residential populations studied by environmental epidemiologists can be time-consuming and expensive. We developed an approach for quantifying chronic exposures for two towns (Marietta and East Liverpool, Ohio) with elevated air Mn concentrations (air-Mn) related to ambient emissions from industrial processes. This was accomplished through the use of measured and modeled data in the communities studied. A novel approach was developed because one of the facilities lacked emissions data for the purposes of modeling. A unit emission rate was assumed over the surface area of both source facilities, and offsite concentrations at receptor residences and air monitoring sites were estimated with the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD). Ratios of all modeled receptor points were created, and a long-running air monitor was identified as a reference location. All ratios were normalized to the reference location. Long-term averages at all residential receptor points were calculated using modeled ratios and data from the reference monitoring location. Modeled five-year average air-Mn exposures ranged from 0.03-1.61 µg/m3 in Marietta and 0.01-6.32 µg/m3 in E

Impact of open manganese mines on the health of children dwelling in the surrounding area

PubMed Central

Duka, Ykateryna D.; Ilchenko, Svetlana I.; Kharytonov, Mykola M.; Vasylyeva, Tetyana L.

2011-01-01

Introduction: Chronic manganese (Mn) exposure is a health hazard associated with the mining and processing of Mn ores. Children living in an area with increased environmental exposure to Mn may have symptoms of chronic toxicity that are different from adults who experience occupational exposure. The aim of the study was to compare health outcomes in a pediatric population living near open Mn mines with a group of children from a reference area and then to develop and implement preventive/rehabilitation measures to protect the children in the mining region. Methods: After environmental assessment, a group of 683 children living in a Mn-rich region of Ukraine were screened by clinical evaluation, detection of sIgA (37 children), micronucleus analysis (56 children), and hair Mn content (166 children). Results: Impaired growth and rickets-like skeletal deformities were observed in 33% of the children. This was a significantly higher percentage than in children in the reference region (15%). The children from the Mn-mining region also had increased salivary levels of immunoglobulin A (104.4±14.2 mcg/ml vs. 49.7±6.1 mcg/ml among the controls (p<0.05), increased serum alpha 1 proteinase inhibitor levels (4.93±0.21 g/l compared with 2.91±0.22 g/l for controls; p<0.001) and greater numbers of micronuclei in the mucous cells of the oral cavity (0.070±0.008 vs. 0.012±0.009, p<0.001). Conclusions: These findings indicate the deleterious health consequences of living in a Mn-mining area. Medical rehabilitation programs were conducted and produced positive results, but further validation of their effectiveness is required. The study provided background information to formulate evidence-based decisions about public health in a region of high Mn exposure. PMID:24149028

The Effect of Rare-Earth Metals on Cast Steels

DTIC Science & Technology

1954-04-01

as the 1-inch section is also illustrated in Figure 23 and consists of tempered bainite and tempered martensite. Both of the control steels (AE-1...section Tempered bainite and tempered martensite 4 inch section Figure 23 Microstructure ol the Mn-Cr-Mo base control steels . Etched with... bainite 4-inch Section Figure 25—Microstructures of the MnCr-Mo + Rare Earths f B cast steels . Etched with picral, SOOX - .1 €. Figure 26

Community Exposure to Air Manganese and Motor and Cognitive Outcomes

EPA Science Inventory

Although manganese (Mn) is an essential nutrient, occupational studies have shown inhaling high levels of Mn can lead to adverse nervous system health effects. Few studies have examined the health effects of air-Mn exposure on adults in a community. We conducted a cross-sectional...

Fracture behavior of neutron-irradiated high-manganese austenitic steels

NASA Astrophysics Data System (ADS)

Yoshida, H.; Miyata, K.; Narui, M.; Kayano, H.

1991-03-01

The instrumented Charpy impact test was applied to study the fracture behavior of high-manganese austenitic steels before and after neutron irradiations. Quarter-size specimens of a commercial high-manganese steel (18% Mn-5% Ni-16% Cr), three reference steels (21% Mn-1% Ni-9% Cr, 20% Mn-1% Ni-11% Cr, 15% Mn-1% Ni-13% Cr) and two model steels (17% Mn-4.5% Si-6.5% Cr, 22% Mn-4.5% Si-6.5% Cr-0.2% N) were used for the impact tests at temperatures between 77 and 523 K. The load-deflection curves showed typical features corresponding to characteristics of the fracture properties. The temperature dependences of fracture energy and failure deflection obtained from the curves clearly demonstrate only small effects up to 2 × 10 23 n/m 2 ( E > 0.1 MeV) and brittleness at room temperature in 17% Mn-Si-Cr steel at 1.6 × 10 25 n/m 2 ( E > 0.1 MeV), while ductility still remains in 22%Mn-Si-Cr steel.

Phytotoxicity of zinc and manganese to seedlings grown in soil contaminated by zinc smelting

USGS Publications Warehouse

Beyer, W.N.; Green, C.E.; Beyer, M.; Chaney, R.L.

2013-01-01

Historic emissions from two zinc smelters have injured the forest on Blue Mountain near Palmerton, Pennsylvania, USA. Seedlings of soybeans and five tree species were grown in a greenhouse in a series of mixtures of smelter-contaminated and reference soils and then phytotoxic thresholds were calculated. As little as 10% Palmerton soil mixed with reference soil killed or greatly stunted seedlings of most species. Zinc was the principal cause of the phytotoxicity to the tree seedlings, although Mn and Cd may also have been phytotoxic in the most contaminated soil mixtures. Calcium deficiency seemed to play a role in the observed phytotoxicity. Exposed soybeans showed symptoms of Mn toxicity. A test of the effect of liming on remediation of the Zn and Mn phytotoxicity caused a striking decrease in Sr-nitrate extractable metals in soils and demonstrated that liming was critical to remediation and restoration.

Cross-sectional aspect ratio modulated electronic properties in Si/Ge core/shell nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Nuo; Lu, Ning; Yao, Yong-Xin

2013-02-28

Electronic structures of (4, n) and (m, 4) (the NW has m layers parallel to the {1 1 1} facet and n layers parallel to {1 1 0}) Si/Ge core/shell nanowires (NWs) along the [1 1 2] direction with cross-sectional aspect ratio (m/n) from 0.36 to 2.25 are studied by first-principles calculations. An indirect to direct band gap transition is observed as m/n decreases, and the critical values of m/n and diameter for the transition are also estimated. The size of the band gap also depends on the aspect ratio. These results suggest that m/n plays an important role inmore » modulating the electronic properties of the NWs.« less

Protective effects of ebselen (Ebs) and para-aminosalicylic acid (PAS) against manganese (Mn)-induced neurotoxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marreilha dos Santos, A.P., E-mail: apsantos@ff.ul.pt; Lucas, Rui L.; Andrade, Vanda

2012-02-01

Chronic, excessive exposure to manganese (Mn) may induce neurotoxicity and cause an irreversible brain disease, referred to as manganism. Efficacious therapies for the treatment of Mn are lacking, mandating the development of new interventions. The purpose of the present study was to investigate the efficacy of ebselen (Ebs) and para-aminosalicylic acid (PAS) in attenuating the neurotoxic effects of Mn in an in vivo rat model. Exposure biomarkers, inflammatory and oxidative stress biomarkers, as well as behavioral parameters were evaluated. Co-treatment with Mn plus Ebs or Mn plus PAS caused a significant decrease in blood and brain Mn concentrations (compared tomore » rats treated with Mn alone), concomitant with reduced brain E{sub 2} prostaglandin (PGE{sub 2}) and enhanced brain glutathione (GSH) levels, decreased serum prolactin (PRL) levels, and increased ambulation and rearing activities. Taken together, these results establish that both PAS and Ebs are efficacious in reducing Mn body burden, neuroinflammation, oxidative stress and locomotor activity impairments in a rat model of Mn-induced toxicity. -- Highlights: ► The manuscript is unique in its approach to the neurotoxicity of Mn. ► The manuscript incorporates molecular, cellular and functional (behavioral) analyses. ► Both PAS and Ebs are effective in restoring Mn behavioral function. ► Both PAS and Ebs are effective in reducing Mn-induced oxidative stress. ► Both PAS and Ebs led to a decrease in Mn-induced neuro-inflammation.« less

Synthesis and Electrochemical Properties Characterization of SnO2-coated LiNi1/3Co1/3Mn1/3O2 Cathode Material for Lithium Ion Batteries

DTIC Science & Technology

2009-01-01

Synthesis and electrochemical properties characterization of SnO2-coated LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion batteries Ping Yang...electrochemical properties characterization of SnO2-coated LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion batteries 5a. CONTRACT NUMBER 5b. GRANT NUMBER...electrochemical reaction. References 1. N Yabuuchi, T Ohzuku, “Novel lithium insertion material of LiCo1/3Ni1/3Mn1/3O2 for advanced lithium - ion batteries ”, J

Dy–Mn–Si as a representative of family of ‘Dy–Transition Metal–Si’ systems: Its isothermal sections, empirical rProd. Type: FTPules and new rare-earth manganese silicides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru; Knotko, A.V.; Yapaskurt, V.O.

2013-10-15

X-ray and microprobe analyses were employed for the investigation of Dy–Mn–Si system at 870/1070/1170 K. The Dy–Mn–Si system, contains the known DyMn{sub 2}Si{sub 2}, DyMnSi and Dy{sub 2}Mn{sub 3}Si{sub 5} compounds and DyMn{sub 4}Si{sub 2}, Dy{sub 2}MnSi{sub 2} and Dy{sub 3}Mn{sub 2}Si{sub 3} were new compounds identified first time and their structure are of the type TmCu{sub 4}Sb{sub 2}, Sc{sub 2}CoSi{sub 2} and Hf{sub 3}Ni{sub 2}Si{sub 3} respectively. The quasi-binary solid solutions were detected at 870/1070/1170 K: the ThMn{sub 12}-type Dy{sub 8}Mn{sub 87}Si{sub 5}, Th{sub 6}Mn{sub 23}-type Dy{sub 23}Mn{sub 72}Si{sub 5}, MgCu{sub 2}-type Dy{sub 33}Mn{sub 58}Si{sub 9} and AlB{sub 2}-typemore » Dy{sub 38}Mn{sub 2}Si{sub 58}. The other binary compounds of the Dy–Mn–Si system do not show any visible solubility. New phases R{sub 2}MnSi{sub 2} and R{sub 3}Mn{sub 2}Si{sub 3} (R=Gd, Tb, Ho–Tm) were found out and their structure of the type Sc{sub 2}CoSi{sub 2} and Hf{sub 3}Ni{sub 2}Si{sub 3} respectively. The specific features of ‘Dy–Transition Metal–Si’ systems were discussed. - Graphical abstract: The isothermal section of Dy–Mn–Si contains the known DyMn{sub 2}Si{sub 2}, DyMnSi, Dy{sub 2}Mn{sub 3}Si{sub 5} and new TmCu{sub 4}Sb{sub 2}-type DyMn{sub 4}Si{sub 2}, Sc{sub 2}CoSi{sub 2}-type Dy{sub 2}MnSi{sub 2} and Hf{sub 3}Ni{sub 2}Si{sub 3}-type Dy{sub 3}Mn{sub 2}Si{sub 3} ternary compounds. The ternary solid solution based on the binary compounds of the Dy–Mn and Dy–Si systems: the ThMn{sub 12}-type Dy{sub 8}Mn{sub 87}Si{sub 5}, Th{sub 6}Mn{sub 23}-type Dy{sub 23}Mn{sub 72}Si{sub 5}, MgCu{sub 2}-type Dy{sub 33}Mn{sub 58}Si{sub 9} and AlB{sub 2}-type Dy{sub 38}Mn{sub 2}Si{sub 58}. The other binary compounds of the Dy–Mn–Si system do not show any visible solubility. New Sc{sub 2}CoSi{sub 2}-type R{sub 2}MnSi{sub 2} and Hf{sub 3}Ni{sub 2}Si{sub 3}-type R{sub 3}Mn{sub 2}Si{sub 3} phases were discovered for R=Gd, Tb, Ho–Tm. Display Omitted - Highlights: • The Dy–Mn–Si section contains three known and three new ternary compounds (phases). • New phase the TmCu{sub 4}Sb{sub 2}-type DyMn{sub 4}Si{sub 2} compound. • New Sc{sub 2}CoSi{sub 2}-type R{sub 2}MnSi{sub 2} and Hf{sub 3}Ni{sub 2}Si{sub 3}-type R{sub 3}Mn{sub 2}Si{sub 3} were detected for R=Gd–Tm. • Dy–Mn–Si supplements the ‘Dy–3d metal–Si’ series and leads to the ‘RT{sub m}X{sub n}’ row's rule.« less

The nervous system effects of occupational exposure on workers in a South African manganese smelter.

PubMed

Myers, Jonathan E; Thompson, Mary Lou; Ramushu, Suzan; Young, Taryn; Jeebhay, Mohamed F; London, Leslie; Esswein, Eric; Renton, Kevin; Spies, Adri; Boulle, Andrew; Naik, Inakshi; Iregren, Anders; Rees, David J

2003-12-01

Five hundred and nine production workers at a manganese (Mn) smelting works comprising eight production facilities and 67 external controls were studied cross-sectionally for Mn related neuroehavioural effects. Exposure measures from personal sampling included Mn in inhalable dust as cumulative exposure indices (CEI) and average intensity (INT). Biological exposure and biological effect measures included blood (MnB), urine (MnU) manganese and serum prolactin. Endpoints included items from the Swedish nervous system questionnaire (Q16), World Health Organisation neurobehavioural core test battery (WHO NCTB), Swedish performance evaluation system (SPES), Luria-Nebraska (LN), and Danish product development (DPD) test batteries, and a brief clinical examination. Potential confounders and effect modifiers included age, educational level, alcohol and tobacco consumption, neurotoxic exposures in previous work, past medical history, previous head injury and home language. Associations were evaluated by multiple linear and logistic regression modelling. Modelling assumptions were tested. Average exposure intensity across all jobs ranged from near 0 (0.06 microg/m3) for external controls to 5.08 mg/m3 for inhalable Mn, and was greater than the ACGIH TLV for 69% of subjects. Results from the large number of tests performed resolved into three groups. Group 1 shows differences between external unexposed referents and all the exposed and/or differences between internal low exposed referents and the rest of the exposed but no further exposure-response relationships. It includes the Santa Ana, Benton and digit-span tests from the WHO NCTB; the hand tapping and endurance tapping tests from the SPES; Luria-Nebraska item 2L; questionnaire items tired, depressed, irritated, having to take notes in order to remember things, and subjects' perception that they had sex less often than normal; a test of clinical abnormality; and increased sway under two conditions (eyes open without foot insulation, eyes open with foot insulation). Group 2 shows the presence of a more substantive exposure-response relationship. It consists of only two tests: and includes the WHO digit-symbol test (although the major impact is at low exposure and therefore counterintuitive, arguably placing this test in group 3) and the LN item 1R which has a step to a poorer score at high exposure. Group 3 contains the overwhelming majority of test results (almost all the questionnaire items, almost all the DPD tests including tremor, sway and diadochokinesia, and serum prolactin) which were either null or counterintuitive (did not make sense). The CEI was the strongest predictor of test abnormalities, except for the clinical test which was more strongly associated with blood manganese. Despite a comprehensive range of endpoints, and levels of exposure ranging from environmental to industrial, this large study of Mn workers found little convincing evidence for a continuum of effects, contributing further questions to current debates about the adequacy of the current ACGIH TLV.

A historical overview of the development of manganese (Mn) pharmacokinetic data under Section 211(b) of the Clean Air Act (CAA)

EPA Science Inventory

Abstract for Manganese 2016A historical overview of the development of manganese (Mn) pharmacokinetic data under Section 211(b) of the Clean Air Act (CAA)William K BoyesBackground. In the 1990’s, the use of methylcyclopentadienyl manganese tricarbonyl (MMT) as an octane-enh...

Manganese and Mn/Ca ratios in soil and vegetation in forests across the northeastern US: Insights on spatial Mn enrichment.

PubMed

Richardson, J B

2017-03-01

Manganese (Mn) cycling in the Critical Zone is important because of its role as an essential nutrient and potential toxicity to plants and organisms. Quantifying Mn enrichment in terrestrial environments has been limited since Mn is monoisotopic. However, elemental ratios of Mn/Ca ratios may be used to determine spatial Mn enrichment and in aboveground and belowground pools. The objectives of this study were to quantify the spatial variation in Mn concentrations and Mn/Ca ratios in foliage, bolewood, forest floor, and mineral soil horizons across the northeastern United States and compare Mn/Ca ratios to estimate enrichment. Forest floor and mineral soil samples were collected from 26 study sites across the northeastern United States and analyzed by strong acid digestion. Foliage and bolewood was collected from 12 of the 26 sites and analyzed for total Mn and Ca. Our results show forest floor and mineral soil horizon Mn concentrations and Mn/Ca ratios were higher at Pennsylvania and New York sites than New Hampshire and Vermont sites. Using a modified isotope equation, enrichment factors (EF) for Mn/Ca ratios were calculated to be ~3.6 in the forest floor, upper and lower mineral soil horizons at sites in New York and Pennsylvania compared to reference sites in New Hampshire and Vermont. Foliar and bolewood Mn concentrations also decreased from Pennsylvania towards New Hampshire. Moreover, foliar and bolewood Mn concentrations were strongly correlated to forest floor, upper, and lower mineral soil Mn concentrations. It was hypothesized that internal cycling (uptake, throughfall, and litterfall) of Mn controls retention of enriched Mn in forests. Geologic influences from a lithologic gradient and soil pH gradient could also influence Mn enrichment in addition to Mn pollution. Ratios of Mn/Ca and other elemental ratios hold promise as geochemical tracers but require further development. Copyright © 2016 Elsevier B.V. All rights reserved.

Prolactin is a peripheral marker of manganese neurotoxicity

PubMed Central

Marreilha dos Santos, AP; Lopes Santos, M; BatorÉu, Maria C; Aschner, M

2011-01-01

Excessive exposure to Mn induces neurotoxicity, referred to as manganism. Exposure assessment relies on Mn blood and urine analyses, both of which show poor correlation to exposure. Accordingly, there is a critical need for better surrogate biomarkers of Mn exposure. The aim of this study was to examine the relationship between Mn exposure and early indicators of neurotoxicity, with particular emphasis on peripheral biomarkers. Male Wistar rats (180–200 g) were injected intraperitoneally with 4 or 8 doses of Mn (10 mg/kg). Mn exposure was evaluated by analysis of Mn levels in brain and blood along with biochemical end-points (see below). Results Brain Mn levels were significantly increased both after 4 and 8 doses of Mn compared with controls (p<0.001). Blood levels failed to reflect a dose-dependent increase in brain Mn, with only the 8-dose treated group showing significant differences (p<0.001). Brain glutathione (GSH) levels were significantly decreased in the 8-dose-treated animals (p<0.001). A significant and dose-dependent increase in prolactin levels was found for both treated groups (p<0.001) compared to controls. In addition, a decrease in motor activity was observed in the 8-dose-treated group compared to controls. Conclusions 1) The present study demonstrates that peripheral blood level is a poor indicator of Mn brain accumulation and exposure; 2) Mn reduces GSH brain levels, likely reflecting oxidative stress; 3) Mn increases blood prolactin levels, indicating changes in the integrity of the dopaminergic system. Taken together these results suggest that peripheral prolactin levels may serve as reliable predictive biomarkers of Mn neurotoxicity. PMID:21262206

Solid state synthesis of Mn{sub 5}Ge{sub 3} in Ge/Ag/Mn trilayers: Structural and magnetic studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myagkov, V.G.; Bykova, L.E.; Matsynin, A.A.

The thin-film solid-state reaction between elemental Ge and Mn across chemically inert Ag layers with thicknesses of (0, 0.3, 1 and 2.2 µm) in Ge/Ag/Mn trilayers was studied for the first time. The initial samples were annealed at temperatures between 50 and 500 °C at 50 °C intervals for 1 h. The initiation temperature of the reaction for Ge/Mn (without a Ag barrier layer) was ~ 120 °C and increased slightly up to ~ 250 °C when the Ag barrier layer thickness increased up to 2.2 µm. In spite of the Ag layer, only the ferromagnetic Mn{sub 5}Ge{sub 3} compoundmore » and the Nowotny phase were observed in the initial stage of the reaction after annealing at 500 °C. The cross-sectional studies show that during Mn{sub 5}Ge{sub 3} formation the Ge is the sole diffusing species. The magnetic and cross-sectional transmission electron microscopy (TEM) studies show an almost complete transfer of Ge atoms from the Ge film, via a 2.2 µm Ag barrier layer, into the Mn layer. We attribute the driving force of the long-range transfer to the long-range chemical interactions between reacting Mn and Ge atoms. - Graphical abstract: The direct visualization of the solid state reaction between Mn and Ge across a Ag buffer layer at 500 °C. - Highlights: • The migration of Ge, via an inert 2.2 µm Ag barrier, into a Mn layer. • The first Mn{sub 5}Ge{sub 3} phase was observed in reactions with different Ag layers. • The Ge is the sole diffusing species during Mn{sub 5}Ge{sub 3} formation • The long-range chemical interactions control the Ge atomic transfer.« less

Red persistent luminescence in rare earth-free AlN:Mn 2+ phosphor

DOE PAGES

Xu, Jian; Cherepy, Nerine J.; Ueda, Jumpei; ...

2017-07-03

Here, we investigated the persistent luminescence (PersL) properties of a rare earth-free Mn 2+ doped AlN (AlN:Mn) red phosphor together with a commercial SrAl 2O 4:Eu 2+, Dy 3+ green persistent phosphor as a reference. Similar to its photoluminescence (PL) spectrum, the PersL spectrum of the AlN:Mn phosphor exhibited a red emission band centered at 600 nm due to the Mn 2+: 4T 1( 4G) → 6A 1( 6S) transition with a relatively narrow full width at half maximum (FWHM) of 43 nm. The luminance of AlN:Mn powders was 0.65 mcd/m 2 at 60 min after ceasing ultraviolet (UV) illumination,more » and its duration upon 0.32 mcd/m 2 could reach over 110 min. An extremely broad thermoluminescence (TL) glow curve was observed ranging from 100 K to 600 K and peaked at around 310 K, indicating a wide trap distribution in this material.« less

Photocatalytic CO2 Reduction to Formate Using a Mn(I) Molecular Catalyst in a Robust Metal-Organic Framework.

PubMed

Fei, Honghan; Sampson, Matthew D; Lee, Yeob; Kubiak, Clifford P; Cohen, Seth M

2015-07-20

A manganese bipyridine complex, Mn(bpydc)(CO)3Br (bpydc = 5,5'-dicarboxylate-2,2'-bipyridine), has been incorporated into a highly robust Zr(IV)-based metal-organic framework (MOF) for use as a CO2 reduction photocatalyst. In conjunction with [Ru(dmb)3](2+) (dmb = 4,4'-dimethyl-2,2'-bipyridine) as a photosensitizer and 1-benzyl-1,4-dihydronicotinamide (BNAH) as a sacrificial reductant, Mn-incorporated MOFs efficiently catalyze CO2 reduction to formate in DMF/triethanolamine under visible-light irradiation. The photochemical performance of the Mn-incorporated MOF reached a turnover number of approximately 110 in 18 h, exceeding that of the homogeneous reference systems. The increased activity of the MOF-incorporated Mn catalyst is ascribed to the struts of the framework providing isolated active sites, which stabilize the catalyst and inhibit dimerization of the singly reduced Mn complex. The MOF catalyst largely retained its crystallinity throughout prolonged catalysis and was successfully reused over several catalytic runs.

Red persistent luminescence in rare earth-free AlN:Mn 2+ phosphor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jian; Cherepy, Nerine J.; Ueda, Jumpei

Here, we investigated the persistent luminescence (PersL) properties of a rare earth-free Mn 2+ doped AlN (AlN:Mn) red phosphor together with a commercial SrAl 2O 4:Eu 2+, Dy 3+ green persistent phosphor as a reference. Similar to its photoluminescence (PL) spectrum, the PersL spectrum of the AlN:Mn phosphor exhibited a red emission band centered at 600 nm due to the Mn 2+: 4T 1( 4G) → 6A 1( 6S) transition with a relatively narrow full width at half maximum (FWHM) of 43 nm. The luminance of AlN:Mn powders was 0.65 mcd/m 2 at 60 min after ceasing ultraviolet (UV) illumination,more » and its duration upon 0.32 mcd/m 2 could reach over 110 min. An extremely broad thermoluminescence (TL) glow curve was observed ranging from 100 K to 600 K and peaked at around 310 K, indicating a wide trap distribution in this material.« less

Intralayer magnetic ordering in Ge/Mn digital alloys

NASA Astrophysics Data System (ADS)

Otrokov, M. M.; Ernst, A.; Ostanin, S.; Fischer, G.; Buczek, P.; Sandratskii, L. M.; Hergert, W.; Mertig, I.; Kuznetsov, V. M.; Chulkov, E. V.

2011-04-01

We present a first-principles investigation of the electronic properties of Ge/Mn digital alloys obtained by the insertion of Mn monolayers in the Ge host. The main attention is devoted to the study of the magnetic properties of the Mn layers for various types of ordering of the Mn atoms. Depending on the type of Mn position three different structures are considered: substitutional, interstitial, and combined substitutional-interstitial. In all three cases numerical structural relaxation of the atomic positions has been performed. We find that the intralayer exchange parameters depend strongly on the crystal structure. For the substitutional and interstitial types of structure the stable magnetic order was found to be ferromagnetic. For the mixed substitutional-interstitial structure the ferromagnetic configuration appears unstable and a complex ferrimagnetic structure forms. The spin-wave excitations are calculated within the Heisenberg model. The critical temperatures of the magnetic phase transitions are determined using Monte Carlo simulations with interatomic exchange parameters obtained for two different magnetic reference states: a ferromagnetic and a disordered local moment state.

Biomonitoring of the environmental genotoxic potential of emissions from a complex of ceramic industries in Monte Carmelo, Minas Gerais, Brazil, using Tradescantia pallida.

PubMed

Campos, Carlos Fernando; Júnior, Edimar Olegário de Campos; Souto, Henrique Nazareth; Sousa, Eduardo de Freitas; Pereira, Boscolli Barbosa

2016-01-01

The micronucleus (MN) test and analysis of heavy metal biological accumulation in Tradescantia pallida (T. pallida) were bioassays used to assess the genotoxic potential of emissions from a complex of ceramic industries into the atmosphere in a city in Brazil that is considered a national reference source for roof tile production. The ceramic industry emission-exposed T. pallida plants were biomonitored during the dry season, in June, July, and August 2013. In addition to the contaminated monitoring site, a reference site in a peri-urban area was utilized, for comparative purposes. Genotoxicity assessments were determined monthly, while heavy metal bioaccumulation was measured at the end of the total exposure period. The MN frequency was significantly greater in T. pallida plants exposed in the ceramic industry emission monitored area compared to the reference site, and highest MN rates were observed in July and August. With respect to heavy metal bioaccumulation in T. pallida leaves, cadmium (Cd) and chromium (Cr) concentrations were significantly higher in plants at the ceramic industry emission monitoring site. Thus, in relation to the parameters assessed, T. pallida was found to be sensitive to atmospheric contamination by heavy metals attributed to ceramic products emissions generated by the ceramic industry, confirming that this plant species may be employed as a reference organism in biomonitoring studies.

Study of the electronic structure and half-metallicity of CaMnO3/BaTiO3 superlattice

NASA Astrophysics Data System (ADS)

Wang, Kai; Jiang, Wei; Chen, Jun-Nan; Huang, Jian-Qi

2016-09-01

In this paper, the electronic structure, magnetic properties and half-metallicity of the CaMnO3/BaTiO3 superlattice are investigated by employing the first-principle calculation based on density functional theory within the GGA or GGA + U exchange-correlation functional. The CaMnO3/BaTiO3 superlattice is constructed by the cubic CaMnO3 and the tetragonal ferroelectric BaTiO3 growing alternately along (0 0 1) direction. The cubic CaMnO3 presents a robust half-metallicity and a metastable ferromagnetic phase. Its magnetic moment is an integral number of 3.000 μB per unit cell. However, the CaMnO3/BaTiO3 superlattice has a stable ferromagnetic phase, for which the magnetic moment is 12.000 μB per unit cell. It also retains the robust half-metallicity which mainly results from the strong hybridization between Mn and O atoms. The results show that the constructed CaMnO3/BaTiO3 superlattice exhibits superior magnetoelectric properties. It may provide a theoretical reference for the design and preparation of new multiferroic materials.

Assembly of a Robust and Economical MnO[subscript2]-Based Reference Electrode

ERIC Educational Resources Information Center

Masse´, Robert C.; Gerken, James B.

2015-01-01

There is a dearth of base-stable reference electrodes that are suitable for use by students in a teaching laboratory or undergraduate research context. To remedy this, we have developed a technique to produce reference electrodes suitable for alkaline environments. By utilizing components of a commercially available alkaline-type battery, an…

Mn and Btex Reference Value Arrays (Final Reports)

EPA Science Inventory

These final reports are a summary of reference value arrays with critical supporting documentation for the chemicals manganese, benzene, toluene, ethylbenzene, and xylene. Each chemical is covered in a separate document, and each is a statement of the status of the available inha...

Metals in agricultural produce associated with acid-mine drainage in Mount Morgan (Queensland, Australia).

PubMed

Vicente-Beckett, Victoria A; McCauley, Gaylene J Taylor; Duivenvoorden, Leo J

2016-01-01

Acid-mine drainage (AMD) into the Dee River from the historic gold and copper mine in Mount Morgan, Queensland (Australia) has been of concern to farmers in the area since 1925. This study sought to determine the levels of AMD-related metals and sulfur in agricultural produce grown near the mine-impacted Dee River, compare these with similar produce grown in reference fields (which had no known AMD influence), and assess any potential health risk using relevant Australian or US guidelines. Analyses of lucerne (Medicago sativa; also known as alfalfa) from five Dee fields showed the following average concentrations (mg/kg dry basis): Cd < 1, Cu 11, Fe 106, Mn 52, Pb < 5, Zn 25 and S 3934; similar levels were found in lucerne hay (used as cattle feed) from two Dee fields. All lucerne and lucerne hay data were generally comparable with levels found in the lucerne reference fields, suggesting no AMD influence; the levels were within the US National Research Council (US NRC) guidelines for maximum tolerable cattle dietary intake. Pasture grass (also cattle feed) from two fields in the Dee River floodplains gave mean concentrations (mg/kg dry) of Cd 0.14, Cu 12, Fe 313, Mn 111, Pb 1.4, Zn 86 and S 2450. All metal levels from the Dee and from reference sites were below the US NRC guidelines for maximum tolerable cattle dietary intake; however, the average Cd, Cu and Fe levels in Dee samples were significantly greater than the corresponding levels in the pasture grass reference sites, suggesting AMD influence in the Dee samples. The average levels in the edible portions of mandarin oranges (Citrus reticulata) from Dee sites (mg/kg wet weight) were Cd 0.011, Cu 0.59, Fe 2.2, Mn 0.56, Pb 0.18, S 91 and Zn 0.96. Cd and Zn were less than or close to, average Fe and Mn levels were at most twice, Cd 1.8 or 6.5 times, and Pb 8.5 or 72 times the maximum levels in raw oranges reported in the US total diet study (TDS) or the Australian TDS, respectively. Average Cd, Fe, Mn, Pb and Zn levels in the citrus reference samples were found to exceed the maximum reported in one or both TDS surveys. Cu, Fe, Mn, Pb and Zn plant-soil transfer factor (TF) values were < 1 for all agricultural samples from both Dee and reference sites, suggesting relatively poor transfer of these metals from soil to plant. In the case of Cd, TF values for Dee pasture grass and citrus fruit samples were 0.14 and 0.73, respectively; lucerne and lucerne hay from both Dee and reference sites gave TF = 10, suggesting some potential risk to cattle, although this conclusion is tentative because Cd levels were close to or less than the detection limit. TF values for S in lucerne, lucerne hay, pasture grass and mandarin oranges from Dee sites were 18, 14, 3 and 3.6, respectively, indicating that S in soil was readily available to plant or fruit. Sulfur in pasture grass and citrus fruit (TF = 11 for both) was apparently more bioavailable at the reference sites than at the Dee sites (TF = 3.0 for pasture grass; TF = 3.6 for citrus fruit).

World Health Organization discontinues its drinking-water guideline for manganese.

PubMed

Frisbie, Seth H; Mitchell, Erika J; Dustin, Hannah; Maynard, Donald M; Sarkar, Bibudhendra

2012-06-01

The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-Water Quality in July 2011. In this edition, the 400-µg/L drinking-water guideline for manganese (Mn) was discontinued with the assertion that because "this health-based value is well above concentrations of manganese normally found in drinking water, it is not considered necessary to derive a formal guideline value." In this commentary, we review the WHO guideline for Mn in drinking water--from its introduction in 1958 through its discontinuation in 2011. For the primary references, we used the WHO publications that documented the Mn guidelines. We used peer-reviewed journal articles, government reports, published conference proceedings, and theses to identify countries with drinking water or potential drinking-water supplies exceeding 400 µg/L Mn and peer-reviewed journal articles to summarize the health effects of Mn. Drinking water or potential drinking-water supplies with Mn concentrations > 400 µg/L are found in a substantial number of countries worldwide. The drinking water of many tens of millions of people has Mn concentrations > 400 µg/L. Recent research on the health effects of Mn suggests that the earlier WHO guideline of 400 µg/L may have been too high to adequately protect public health. The toxic effects and geographic distribution of Mn in drinking-water supplies justify a reevaluation by the WHO of its decision to discontinue its drinking-water guideline for Mn.

Speciation analysis of Mn(II)/Mn(VII) using Fe3O4@ionic liquids-β-cyclodextrin polymer magnetic solid phase extraction coupled with ICP-OES.

PubMed

Chen, Songqing; Qin, Xingxiu; Gu, Weixi; Zhu, Xiashi

2016-12-01

Ionic liquids-β-cyclodextrin polymer (ILs-β-CDCP) was attached on Fe 3 O 4 nanoparticles to prepare magnetic solid phase extraction agent (Fe 3 O 4 @ILs-β-CDCP). The properties and morphology of Fe 3 O 4 @ILs-β-CDCP were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction(XRD), size distribution and magnetic analysis. A new method of magnetic solid phase extraction (MSPE) coupled to ICP-OES for the speciation of Mn(II)/Mn(VII) in water samples was established. The results showed that Mn(VII) and total manganese [Mn(II)+Mn(VII)] were quantitatively extracted after adjusting aqueous sample solution to pH 6.0 and 10.0, respectively. Mn(II) was calculated by subtraction of Mn(VII) from total manganese. Fe 3 O 4 @ILs-β-CDCP showed a higher adsorption capacity toward Mn(II) and Mn(VII). Several factors, such as the pH value, extraction temperature and sample volume, were optimized to achieve the best extraction efficiency. Moreover, the adsorption ability of Fe 3 O 4 @ILs-β-CDCP would not be significantly lower after reusing of 10 times. The accuracy of the developed method was confirmed by analyzing certified reference materials (GSB 07-1189-2000), and by spiking spring water, city water and lake water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiple-orifice liquid injection into hypersonic airstreams and applications to ram C-3 flight

NASA Technical Reports Server (NTRS)

Weaver, W. L.

1972-01-01

Experimental data are presented for the oblique injection of water and three electrophilic liquids (fluorocarbon compounds) through multiple-orifice nozzles from a flat plate and the sides of a hemisphere-cone (0.375 scale of RAM C spacecraft) into hypersonic airstreams. The nozzle patterns included single and multiple orifices, single rows of nozzles, and duplicates of the RAM C-III nozzles. The flat-plate tests were made at Mach 8. Total pressure was varied from 3.45 MN/m2 to 10.34 MN/m2, Reynolds number was varied form 9,840,000 per meter to 19,700,000 per meter, and liquid injection pressure was varied from 0.69 MN/m2 to 3.5 MN/m2. The hemisphere-cone tests were made at Mach 7.3. Total pressure was varied from 1.38 MN/m2, to 6.89 MN/m2, Reynolds number was varied from 3,540,000 per meter to 17,700,000 per meter, and liquid-injection pressure was varied from 0.34 MN/m2 to 4.14 MN/m2. Photographs of the tests and plots of liquid-penetration and spray cross-section area are presented. Maximum penetration was found to vary as the square root of the dynamic-pressure ratio and the square root of the total injection nozzle area. Spray cross-section area was linear with maximum penetration. The test results are used to compute injection parameters for the RAM C-3 flight injection experiment.

Atomic data on inelastic processes in low-energy manganese-hydrogen collisions

NASA Astrophysics Data System (ADS)

Belyaev, Andrey K.; Voronov, Yaroslav V.

2017-10-01

Aims: The aim of this paper is to calculate cross sections and rate coefficients for inelastic processes in low-energy Mn + H and Mn+ + H- collisions, especially, for processes with high and moderate rate coefficients. These processes are required for non-local thermodynamic equilibrium (non-LTE) modeling of manganese spectra in cool stellar atmospheres, and in particular, for metal-poor stars. Methods: The calculations of the cross sections and the rate coefficients were performed by means of the quantum model approach within the framework of the Born-Oppenheimer formalism, that is, the asymptotic semi-empirical method for the electronic MnH molecular structure calculation followed by the nonadiabatic nuclear dynamical calculation by means of the multichannel analytic formulas. Results: The cross sections and the rate coefficients for low-energy inelastic processes in manganese-hydrogen collisions are calculated for all transitions between 21 low-lying covalent states and one ionic state. We show that the highest values of the cross sections and the rate coefficients correspond to the mutual neutralization processes into the final atomic states Mn(3d54s(7S)5s e 6S), Mn(3d54s(7S)5p y 8P°), Mn(3d54s(7S)5s e 8S), Mn(3d54s(7S)4d e 8D) [the first group], the processes with the rate coefficients (at temperature T = 6000 K) of the values 4.38 × 10-8, 2.72 × 10-8, 1.98 × 10-8, and 1.59 × 10-8 cm3/ s, respectively, that is, with the rate coefficients exceeding 10-8 cm3/ s. The processes with moderate rate coefficients, that is, with values between 10-10 and 10-8 cm3/ s include many excitation, de-excitation, mutual neutralization and ion-pair formation processes. In addition to other processes involving the atomic states from the first group, the processes from the second group include those involving the following atomic states: Mn(3d5(6S)4s4p (1P°) y 6P°), Mn(3d54s(7S)4d e 6D), Mn(3d54s(7S)5p w 6P°), Mn(3d5(4P)4s4p (3P°) y 6D°), Mn(3d5(4G)4s4p (3P°) y 6F°). The processes with the highest and moderate rate coefficients are expected to be important for non-LTE modeling of manganese spectra in stellar atmospheres. Rate coefficients Kif(T) for the excitation, de-excitation, mutual neutralization, and ion-pair formation processes in manganese-hydrogen collisions are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/A106

The reflectivity of Mars at 1064 nm: Derivation from Mars Orbiter Laser Altimeter data and application to climatology and meteorology

NASA Astrophysics Data System (ADS)

Heavens, N. G.

2017-06-01

The Mars Orbiter Laser Altimeter (MOLA) on board Mars Global Surveyor (MGS) made > 108 measurements of the reflectivity of Mars at 1064 nm (R1064) by both active sounding and passive radiometry. Past studies of R1064 neglected the effects of atmospheric opacity and viewing geometry on both active and passive measurements and also identified a potential calibration issue with passive radiometry. Therefore, as yet, there exists no acceptable reference R1064 to derive a column opacity product for atmospheric studies and planning future orbital lidar observations. Here, such a reference R1064 is derived by seeking R1064M,N: a Minnaert-corrected normal albedo under clear conditions and assuming minimal phase angle dependence. Over darker surfaces, R1064M,N and the absolute level of atmospheric opacity were estimated from active sounding. Over all surfaces, the opacity derived from active sounding was used to exclude passive radiometry measurements made under opaque conditions and estimate R1064M,N. These latter estimates then were re-calibrated by comparison with RM,N derived from Hubble Space Telescope (HST) observations over areas of approximately uniform reflectivity. Estimates of R1064M,N from re-calibrated passive radiometry typically agree with HST observations within 10%. The resulting R1064M,N is then used to derive and quantify the uncertainties of a column opacity product, which can be applied to meteorological and climatological studies of Mars, particularly to detect and measure mesoscale cloud/aerosol structures.

Relationship between blood manganese levels and children's attention, cognition, behavior, and academic performance--a nationwide cross-sectional study.

PubMed

Bhang, Soo-Young; Cho, Soo-Churl; Kim, Jae-Won; Hong, Yun-Chul; Shin, Min-Sup; Yoo, Hee Jeong; Cho, In Hee; Kim, Yeni; Kim, Bung-Nyun

2013-10-01

Manganese (Mn) is neurotoxic at high concentrations. However, Mn is an essential element that can protect against oxidative damage; thus, extremely low levels of Mn might be harmful. Our aim was to examine whether either high or low environmental Mn exposure is related to academic and attention function development among school-aged children. This cross-sectional study included 1089 children 8-11 years of age living in five representative areas in South Korea. Blood Mn, blood lead, and urine cotinine were measured. We assessed IQ with the Wechsler Abbreviated Scale of Intelligence; attention with a computerized continuous performance test called the Attention-deficit/hyperactivity disorder (ADHD) Diagnostic System (ADS), the Korean version of the Stroop Color-Word Test, the Children's Color Trails Test (CCTT), and the ADHD Rating Scale; academic functions with the Learning Disability Evaluation Scale (LDES); and emotional and behavioral problems with the Korean version of the Child Behavior Checklist (CBCL). We further assessed the presence of ADHD using a highly structured diagnostic interview, the Diagnostic Interview Schedule for Children Version IV (DISC-IV). The median blood concentration of Mn was 14.14 µg/L. We observed a nonlinear association between the CCTT2 completion time and the CPT commission error (F=3.14, p=0.03 and F=4.05, p=0.01, respectively). We divided the data into three groups: lower (<8.154 µg/L), and upper 5th percentile (>21.453 µg/L) and middle 90th percentile to determine whether a lack or overload of Mn could cause adverse effects. After adjusting for urine cotinine, blood lead, children's IQ, and other potential confounders, the high Mn group showed lower scores in thinking (B=-0.83, p=0.006), reading (B=-0.93, p=0.004), calculations (B=-0.72, p=0.005), and LQ (B=-4.06, p=0.006) in the LDES and a higher commission error in the CPT (B=8.02, p=0.048). The low Mn group showed lower color scores in the Stroop test (B=-3.24, p=0.040). We found that excess Mn in children is associated with lower scores of thinking, reading, calculation, and LQ in the LDES and higher scores of commission error in the ADS test. In contrast, lower Mn in children is associated with lower color scores in the Stroop test. The findings of this cross-sectional study suggest that excess exposure or deficiency of Mn can cause harmful effects in children. Copyright © 2013 Elsevier Inc. All rights reserved.

Blood manganese as an exposure biomarker: State of the evidence

PubMed Central

Baker, Marissa G.; Simpson, Christopher D.; Stover, Bert; Sheppard, Lianne; Checkoway, Harvey; Racette, Brad A.; Seixas, Noah S.

2014-01-01

Despite evidence of adverse health effects resulting from exposure to manganese (Mn), biomarkers of exposure are poorly understood. To enhance understanding, mean blood Mn (MnB) and mean air Mn (MnA) were extracted from 63 exposure groups in 24 published papers, and the relationship was modeled using segmented regression. On a log/log scale, a positive association between MnA and MnB was observed among studies reporting MnA concentrations above about 10 μg/m3, although interpretation is limited by largely cross-sectional data, study design variability, and differences in exposure monitoring methods. Based on the results of the segmented regression, we hypothesize that below the concentration of about 10 μg/m3, Mn in the body is dominated by dietary Mn, and additional inhaled Mn only causes negligible changes in Mn levels unless the inhaled amount is substantial. However, stronger study designs are required to account for temporal characteristics of the MnA to MnB relationships which reflect the underlying physiology and toxicokinetics of Mn uptake and distribution. Thus, we present an inception cohort study design we have conducted among apprentice welders, and the analytical strengths this study design offers. To determine if blood could be a useful biomarker for Mn to be utilized by industrial hygienists in general industry requires additional time-specific analyses, which our inception cohort study design will allow. PMID:24579750

Core-shell structured MnSiO3 supported with CNTs as a high capacity anode for lithium-ion batteries.

PubMed

Feng, Jing; Li, Qin; Wang, Huijun; Zhang, Min; Yang, Xia; Yuan, Ruo; Chai, Yaqin

2018-04-17

Metal silicates are good candidates for use in lithium ion batteries (LIBs), however, their electrochemical performance is hindered by their poor electrical conductivity and volume expansion during Li+ insertion/desertion. In this work, one-dimensional core-shell structured MnSiO3 supported with carbon nanotubes (CNTs) (referred to as CNT@MnSiO3) with good conductivity and electrochemical performance has been successfully synthesized using a solvothermal process under moderate conditions. In contrast to traditional composites of CNTs and nanoparticles, the CNT@MnSiO3 composite in this work is made up of CNTs with a layer of MnSiO3 on the surface. The one-dimensional CNT@MnSiO3 nanotubes provide a useful channel for transferring Li+ ions during the discharge/charge process, which accelerates the Li+ diffusion speed. The CNTs inside the structure not only enhance the conductivity of the composite, but also prevent volume expansion. A high reversible capacity (920 mA h g-1 at 500 mA g-1 over 650 cycles) and good rate performance were obtained for CNT@MnSiO3, showing that this strategy of synthesizing coaxial CNT@MnSiO3 nanotubes offers a promising method for preparing other silicates for LIBs or other applications.

Sulfur evolution in chemical looping combustion of coal with MnFe2O4 oxygen carrier.

PubMed

Wang, Baowen; Gao, Chuchang; Wang, Weishu; Zhao, Haibo; Zheng, Chuguang

2014-05-01

Chemical looping combustion (CLC) of coal has gained increasing attention as a novel combustion technology for its advantages in CO2 capture. Sulfur evolution from coal causes great harm from either the CLC operational or environmental perspective. In this research, a combined MnFe2O4 oxygen carrier (OC) was synthesized and its reaction with a typical Chinese high sulfur coal, Liuzhi (LZ) bituminous coal, was performed in a thermogravimetric analyzer (TGA)-Fourier transform infrared (FT-IR) spectrometer. Evolution of sulfur species during reaction of LZ coal with MnFe2O4 OC was systematically investigated through experimental means combined with thermodynamic simulation. TGA-FTIR analysis of the LZ reaction with MnFe2O4 indicated MnFe2O4 exhibited the desired superior reactivity compared to the single reference oxides Mn3O4 or Fe2O3, and SO2 produced was mainly related to oxidization of H2S by MnFe2O4. Experimental analysis of the LZ coal reaction with MnFe2O4, including X-ray diffraction and X-ray photoelectron spectroscopy analysis, verified that the main reduced counterparts of MnFe2O4 were Fe3O4 and MnO, in good agreement with the related thermodynamic simulation. The obtained MnO was beneficial to stabilize the reduced MnFe2O4 and avoid serious sintering, although the oxygen in MnO was not fully utilized. Meanwhile, most sulfur present in LZ coal was converted to solid MnS during LZ reaction with MnFe2O4, which was further oxidized to MnSO4. Finally, the formation of both MnS and such manganese silicates as Mn2SiO4 and MnSiO3 should be addressed to ensure the full regeneration of the reduced MnFe2O4. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Signature of a highly spin polarized resonance state at Co2MnSi(0 0 1)/Ag(0 0 1) interfaces

NASA Astrophysics Data System (ADS)

Lidig, Christian; Minár, Jan; Braun, Jürgen; Ebert, Hubert; Gloskovskii, Andrei; Kronenberg, Alexander; Kläui, Mathias; Jourdan, Martin

2018-04-01

We investigated interfaces of halfmetallic Co2MnSi(1 0 0) Heusler thin films with Ag(1 0 0), Cr(1 0 0), Cu and Al layers relevant for spin valves by high energy x-ray photoemission spectroscopy (HAXPES). Experiments on Co2MnSi samples with an Ag(1 0 0) interface showed a characteristic spectral shoulder feature close to the Fermi edge, which is strongly diminished or suppressed at Co2MnSi (1 0 0) interfaces with the other metallic layers. This feature is found to be directly related to the Co2MnSi(1 0 0) layer, as reflected by control experiments with reference non-magnetic films, i.e. without the Heusler layer. By comparison with HAXPES calculations, the shoulder feature is identified as originating from an interface state related to a highly spin polarized surface resonance of Co2MnSi (1 0 0).

Large low-field magnetocaloric effect in directionally solidified Ni55Mn18+xGa27-x (x = 0, 1, 2) alloys

NASA Astrophysics Data System (ADS)

Li, Zhenzhuang; Li, Zongbin; Yang, Bo; Yang, Yiqiao; Zhang, Yudong; Esling, Claude; Zhao, Xiang; Zuo, Liang

2018-01-01

The magnetostructural transformation and magnetocaloric effect of directionally solidified polycrystalline Ni55Mn18+xGa27-x (x = 0, 1, 2) alloys were studied. It is shown the directionally solidified alloys form coarse columnar-shaped grains with strong 〈0 0 1〉A (the subscript A refers to austenite) preferred orientation along the solidification direction. Through Mn substitution for Ga, a coupled magnetostructural transformation was realized in Ni55Mn19Ga26 and Ni55Mn20Ga25 alloys. Large adiabatic temperature variation (ΔTad) of 1.47 K and 1.57 K under the low field change of 1.5 T were achieved in these two alloys, respectively. Such ΔTad values are obviously higher than that obtained from a single martensitic transformation and magnetic transition. The present results demonstrate that proper composition tuning to achieve magnetostructural transformation as well as increasing the grain size and preferential orientation degree through directional solidification could be an economical processing route to optimize magnetocaloric properties in polycrystalline Ni-Mn-Ga based alloys.

Modeling the Kinetics of Contaminants Oxidation and the Generation of Manganese(III) in the Permanganate/Bisulfite Process.

PubMed

Sun, Bo; Dong, Hongyu; He, Di; Rao, Dandan; Guan, Xiaohong

2016-02-02

Permanganate can be activated by bisulfite to generate soluble Mn(III) (noncomplexed with ligands other than H2O and OH(-)) which oxidizes organic contaminants at extraordinarily high rates. However, the generation of Mn(III) in the permanganate/bisulfite (PM/BS) process and the reactivity of Mn(III) toward emerging contaminants have never been quantified. In this work, Mn(III) generated in the PM/BS process was shown to absorb at 230-290 nm for the first time and disproportionated more easily at higher pH, and thus, the utilization rate of Mn(III) for decomposing organic contaminant was low under alkaline conditions. A Mn(III) generation and utilization model was developed to get the second-order reaction rate parameters of benzene oxidation by soluble Mn(III), and then, benzene was chosen as the reference probe to build a competition kinetics method, which was employed to obtain the second-order rate constants of organic contaminants oxidation by soluble Mn(III). The results revealed that the second-order rate constants of aniline and bisphenol A oxidation by soluble Mn(III) were in the range of 10(5)-10(6) M(-1) s(-1). With the presence of soluble Mn(III) at micromolar concentration, contaminants could be oxidized with the observed rates several orders of magnitude higher than those by common oxidation processes, implying the great potential application of the PM/BS process in water and wastewater treatment.

World Health Organization Discontinues Its Drinking-Water Guideline for Manganese

PubMed Central

Frisbie, Seth H.; Mitchell, Erika J.; Dustin, Hannah; Maynard, Donald M.

2012-01-01

Background: The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-Water Quality in July 2011. In this edition, the 400-µg/L drinking-water guideline for manganese (Mn) was discontinued with the assertion that because “this health-based value is well above concentrations of manganese normally found in drinking water, it is not considered necessary to derive a formal guideline value.” Objective: In this commentary, we review the WHO guideline for Mn in drinking water—from its introduction in 1958 through its discontinuation in 2011. Methods: For the primary references, we used the WHO publications that documented the Mn guidelines. We used peer-reviewed journal articles, government reports, published conference proceedings, and theses to identify countries with drinking water or potential drinking-water supplies exceeding 400 µg/L Mn and peer-reviewed journal articles to summarize the health effects of Mn. Discussion: Drinking water or potential drinking-water supplies with Mn concentrations > 400 µg/L are found in a substantial number of countries worldwide. The drinking water of many tens of millions of people has Mn concentrations > 400 µg/L. Recent research on the health effects of Mn suggests that the earlier WHO guideline of 400 µg/L may have been too high to adequately protect public health. Conclusions: The toxic effects and geographic distribution of Mn in drinking-water supplies justify a reevaluation by the WHO of its decision to discontinue its drinking-water guideline for Mn. PMID:22334150

Heavy Metals in Soil and Salad in the Proximity of Historical Ferroalloy Emission

PubMed Central

Ferri, Roberta; Donna, Filippo; Smith, Donald R.; Guazzetti, Stefano; Zacco, Annalisa; Rizzo, Luigi; Bontempi, Elza; Zimmerman, Neil J.; Lucchini, Roberto G.

2016-01-01

Emissions of manganese (Mn), lead (Pb), iron (Fe), zinc (Zn), copper (Cu) from ferro-alloy operations has taken place in Valcamonica, a pre-Alp valley in the province of Brescia, Italy, for about a century until 2001. Metal concentrations were measured in the soil of local home gardens and in the cultivated vegetables. Soil analysis was carried out using a portable X-Ray Fluorescence (XRF) spectrometer in both surface soil and at 10 cm depth. A subset of soil samples (n = 23) additionally was analysed using the modified BCR sequential extraction method and ICP-OES for intercalibration with XRF (XRF Mn = 1.33 * total OES Mn – 71.8; R = 0.830, p < 0.0001). Samples of salads (Lactuca sativa and Chichorium spp.) were analyzed with a Total Reflection X-Ray Fluorescence (TXRF) technique. Vegetable and soil metal measurements were performed in 59 home gardens of Valcamonica, and compared with 23 gardens from the Garda Lake reference area. Results indicate significantly higher levels of soil Mn (median 986 ppm vs 416 ppm), Pb (median 46.1 ppm vs 30.2 ppm), Fe (median 19,800 ppm vs 13,100 ppm) in the Valcamonica compared to the reference area. Surface soil levels of all metals were significantly higher in surface soil compared to deeper soil, consistent with atmospheric deposition. Significantly higher levels of metals were shown also in lettuce from Valcamonica for Mn (median 53.6 ppm vs 30.2) and Fe (median 153 vs 118). Metals in Chichorium spp. did not differ between the two areas. Surface soil metal levels declined with increasing distance from the closest ferroalloy plant, consistent with plant emissions as the source of elevated soil metal levels. A correlation between Mn concentrations in soil and lettuce was also observed. These data show that historic ferroalloy plant activity, which ended nearly a decade before this study, has contributed to the persistence of increased Mn levels in locally grown vegetables. Further research is needed to assess whether this increase can lead to adverse effects in humans and plants especially for Mn, an essential element that can be toxic in humans when exceeding the homeostatic ranges. PMID:27818841

Insertion of a single-molecule magnet inside a ferromagnetic lattice based on a 3D bimetallic oxalate network: towards molecular analogues of permanent magnets.

PubMed

Clemente-León, Miguel; Coronado, Eugenio; Gómez-García, Carlos J; López-Jordà, Maurici; Camón, Agustín; Repollés, Ana; Luis, Fernando

2014-02-03

The insertion of the single-molecule magnet (SMM) [Mn(III)(salen)(H2O)]2(2+) (salen(2-) = N,N'-ethylenebis-(salicylideneiminate)) into a ferromagnetic bimetallic oxalate network affords the hybrid compound [Mn(III)(salen)(H2O)]2[Mn(II)Cr(III)(ox)3]2⋅(CH3OH)⋅(CH3CN)2 (1). This cationic Mn2 cluster templates the growth of crystals formed by an unusual achiral 3D oxalate network. The magnetic properties of this hybrid magnet are compared with those of the analogous compounds [Mn(III)(salen)(H2O)]2[Zn(II)Cr(III)(ox)3]2⋅(CH3OH)⋅(CH3CN)2 (2) and [In(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]⋅(H2O)0.25⋅(CH3OH)0.25⋅(CH3CN)0.25 (3), which are used as reference compounds. In 2 it has been shown that the magnetic isolation of the Mn2 clusters provided by their insertion into a paramagnetic oxalate network of Cr(III) affords a SMM behavior, albeit with blocking temperatures well below 500 mK even for frequencies as high as 160 kHz. In 3 the onset of ferromagnetism in the bimetallic Mn(II) Cr(III) network is observed at Tc = 5 K. Finally, in the hybrid compound 1 the interaction between the two magnetic networks leads to the antiparallel arrangement of their respective magnetizations, that is, to a ferrimagnetic phase. This coupling induces also important changes on the magnetic properties of 1 with respect to those of the reference compounds 2 and 3. In particular, compound 1 shows a large magnetization hysteresis below 1 K, which is in sharp contrast with the near-reversible magnetizations that the SMMs and the oxalate ferromagnetic lattice show under the same conditions. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of certain features of the electronic structure of the ternary alloys Ni2(Mn, Fe) and Ni3(Mn, Co)

NASA Technical Reports Server (NTRS)

Zhukova, V. M.; Fadin, V. P.

1981-01-01

The changes in electronic structure related to transport processes occurring during the alloying of he alloy Ni3Mn with iron and cobalt, and the ordering of the ternary alloys thus formed are presented. The Hall effect, the absolute thermal emf, the internal saturation induction, the Nernst-Ettingshausen constant, and the electrical resistivity were measured. Results show a decrease in the contribution of hole sections of the Fermi surface to the transport process occurs together with a considerable increase in the contribution of electron sections. In this case, the mobility of 3 dimensional holes decreases and the mobility of 4s electrons increases considerably.

Intellectual Impairment in School-Age Children Exposed to Manganese from Drinking Water

PubMed Central

Bouchard, Maryse F.; Sauvé, Sébastien; Barbeau, Benoit; Legrand, Melissa; Brodeur, Marie-Ève; Bouffard, Thérèse; Limoges, Elyse; Bellinger, David C.; Mergler, Donna

2011-01-01

Background Manganese is an essential nutrient, but in excess it can be a potent neurotoxicant. Despite the common occurrence of manganese in groundwater, the risks associated with this source of exposure are largely unknown. Objectives Our first aim was to assess the relations between exposure to manganese from drinking water and children’s intelligence quotient (IQ). Second, we examined the relations between manganese exposures from water consumption and from the diet with children’s hair manganese concentration. Methods This cross-sectional study included 362 children 6–13 years of age living in communities supplied by groundwater. Manganese concentration was measured in home tap water (MnW) and children’s hair (MnH). We estimated manganese intake from water ingestion and the diet using a food frequency questionnaire and assessed IQ with the Wechsler Abbreviated Scale of Intelligence. Results The median MnW in children’s home tap water was 34 μg/L (range, 1–2,700 μg/L). MnH increased with manganese intake from water consumption, but not with dietary manganese intake. Higher MnW and MnH were significantly associated with lower IQ scores. A 10-fold increase in MnW was associated with a decrease of 2.4 IQ points (95% confidence interval: −3.9 to −0.9; p < 0.01), adjusting for maternal intelligence, family income, and other potential confounders. There was a 6.2-point difference in IQ between children in the lowest and highest MnW quintiles. MnW was more strongly associated with Performance IQ than Verbal IQ. Conclusions The findings of this cross-sectional study suggest that exposure to manganese at levels common in groundwater is associated with intellectual impairment in children. PMID:20855239

Intellectual impairment in school-age children exposed to manganese from drinking water.

PubMed

Bouchard, Maryse F; Sauvé, Sébastien; Barbeau, Benoit; Legrand, Melissa; Brodeur, Marie-Ève; Bouffard, Thérèse; Limoges, Elyse; Bellinger, David C; Mergler, Donna

2011-01-01

Manganese is an essential nutrient, but in excess it can be a potent neurotoxicant. Despite the common occurrence of manganese in groundwater, the risks associated with this source of exposure are largely unknown. Our first aim was to assess the relations between exposure to manganese from drinking water and children's intelligence quotient (IQ). Second, we examined the relations between manganese exposures from water consumption and from the diet with children's hair manganese concentration. This cross-sectional study included 362 children 6-13 years of age living in communities supplied by groundwater. Manganese concentration was measured in home tap water (MnW) and children's hair (MnH). We estimated manganese intake from water ingestion and the diet using a food frequency questionnaire and assessed IQ with the Wechsler Abbreviated Scale of Intelligence. The median MnW in children's home tap water was 34 µg/L (range, 1-2,700 µg/L). MnH increased with manganese intake from water consumption, but not with dietary manganese intake. Higher MnW and MnH were significantly associated with lower IQ scores. A 10-fold increase in MnW was associated with a decrease of 2.4 IQ points (95% confidence interval: -3.9 to -0.9; p < 0.01), adjusting for maternal intelligence, family income, and other potential confounders. There was a 6.2-point difference in IQ between children in the lowest and highest MnW quintiles. MnW was more strongly associated with Performance IQ than Verbal IQ. The findings of this cross-sectional study suggest that exposure to manganese at levels common in groundwater is associated with intellectual impairment in children.

Thermodynamic data from redox reactions at high temperatures. II. The MnO-0Mn3O4 oxygen buffer, and implications for the thermodynamic properties of MnO and Mn3O4

NASA Astrophysics Data System (ADS)

O'Neill, Hugh St. C.; Pownceby, Mark I.

1993-09-01

Theμ _{O_2 } defined by the reaction 6 MnO+O2 =2 Mn3O4 has been determined from 917 to 1,433 K using electrochemical cells (with calcia-stabilized zirconta, CSZ) of the type: MediaObjects/410_2005_BF01046534_f2.tif Steady emfs were achieved rapidly at all temperatures on both increasing and decreasing temperature, indicating that the MnO-Mn3O4 oxygen buffer equilibrates relatively easily. It therefore makes a useful alternative choice in experimental petrology to Fe2O3-Fe3O4 for buffering oxygen potentials at oxidized values. The results are (in J/mol, temperature in K, reference pressure 1 bar);μ _{O_2 } (±200)=-563,241+1,761.758 T-220.490 T in T+0.101819 T 2 with an uncertainty of ±200 J/mol. Third law analysis of these data, including a correction for the deviations in stoichiometry of MnO, implies S 298.15 for Mn3O4 of 166.6 J/K · mol, which is 2.5 J/K · mol higher than the calorimetric determination of Robie and Hemingway (1985). The low value of the calorimetric entropy may be due to incomplete ordering of the magnetic spins. The third law value of Δ r H {298.15/0} is-450.09 kJ/mol, which is significantly different from the calorimetric value of-457.5±3.4 kJ/mol, calculated from Δ f H {298.15/0} of MnO and Mn3O4, implying a small error in one or both of these latter.

Manganese concentrations in the air of the Montreal (Canada) subway in relation to surface automobile traffic density.

PubMed

Boudia, Nacéra; Halley, Renée; Kennedy, Greg; Lambert, Jean; Gareau, Lise; Zayed, Joseph

2006-07-31

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn), used since 1976 in Canadian gasoline as an octane enhancer. Its combustion leads to the emission of Mn particles. Several studies carried out by our research group have established a correlation between atmospheric Mn concentrations and automobile traffic density, suggesting that MMT in gasoline could play a significant role. This study aims to measure Mn concentrations in the air of the underground subway in Montreal (Canada) and to examine the relation with nearby surface automobile traffic density and, by extension, with the use of MMT in gasoline. Three subway stations were chosen for their location in different microenvironments with different traffic densities. Respirable (MnR<5 microm) and total Mn (MnT) were sampled over two weeks, 5 days/week, 12 h/day. For the station located in the lower traffic density area, relatively low levels of MnR and MnT were found, with averages of 0.018 and 0.032 microg/m(3), respectively. These concentrations are within the range of the background levels in Montreal. For the other two stations, the average concentrations of MnR were twice as high and exceeded the US EPA reference concentration of 0.05 microg/m(3). Although there may be several sources of Mn from different components of the subway structure and vehicles, no correlation was found between subway traffic and atmospheric Mn in the subway. Since the air in the underground subway is pumped directly from outside without filtration, our findings strongly suggest that the combustion of MMT in automobiles is an important factor.

High-performance nanostructured supercapacitors on a sponge.

PubMed

Chen, Wei; Rakhi, R B; Hu, Liangbing; Xie, Xing; Cui, Yi; Alshareef, H N

2011-12-14

A simple and scalable method has been developed to fabricate nanostructured MnO2-carbon nanotube (CNT)-sponge hybrid electrodes. A novel supercapacitor, henceforth referred to as "sponge supercapacitor", has been fabricated using these hybrid electrodes with remarkable performance. A specific capacitance of 1,230 F/g (based on the mass of MnO2) can be reached. Capacitors based on CNT-sponge substrates (without MnO2) can be operated even under a high scan rate of 200 V/s, and they exhibit outstanding cycle performance with only 2% degradation after 100,000 cycles under a scan rate of 10 V/s. The MnO2-CNT-sponge supercapacitors show only 4% of degradation after 10,000 cycles at a charge-discharge specific current of 5 A/g. The specific power and energy of the MnO2-CNT-sponge supercapacitors are high with values of 63 kW/kg and 31 Wh/kg, respectively. The attractive performances exhibited by these sponge supercapacitors make them potentially promising candidates for future energy storage systems.

Mechanistic-empirical evaluation of the Mn/ROAD low volume road test sections.

DOT National Transportation Integrated Search

1998-05-01

The purpose of this study was to use Mn/ROAD mainline flexible pavement data to verify, refine, and modify the Illinois Department of Transportation (IDOT) Mechanistic-Empirical (M-E) based flexible pavement design procedures and concepts.

MN/DOT research peer exchange : pooled fund financial management, August 20 - 23, 2007 : final report.

DOT National Transportation Integrated Search

2007-08-01

The Minnesota Department of Transportation Research Services Section hosted a peer exchange : on August 20-23, 2007 in Bloomington, Minnesota. Representatives from five state DOTs and : FHWA-Headquarters joined representatives from Mn/DOT and FHWA-Mi...

Application of empirical and mechanistic-empirical pavement design procedures to Mn/ROAD concrete pavement test sections

DOT National Transportation Integrated Search

1997-05-01

Current pavement design procedures are based principally on empirical approaches. The current trend toward developing more mechanistic-empirical type pavement design methods led Minnesota to develop the Minnesota Road Research Project (Mn/ROAD), a lo...

A zebrafish model of manganism reveals reversible and treatable symptoms that are independent of neurotoxicity

PubMed Central

Bakthavatsalam, Subha; Das Sharma, Shreya; Sonawane, Mahendra; Thirumalai, Vatsala; Datta, Ankona

2014-01-01

Manganese (manganese ion; referred to as Mn) is essential for neuronal function, yet it is toxic at high concentrations. Environmental and occupational exposure to high concentrations of Mn causes manganism, a well-defined movement disorder in humans, with symptoms resembling Parkinson’s disease (PD). However, manganism is distinct from PD and the neural basis of its pathology is poorly understood. To address this issue, we generated a zebrafish model of manganism by incubating larvae in rearing medium containing Mn. We find that Mn-treated zebrafish larvae exhibit specific postural and locomotor defects. Larvae begin to float on their sides, show a curved spine and swim in circles. We discovered that treatment with Mn causes postural defects by interfering with mechanotransduction at the neuromasts. Furthermore, we find that the circling locomotion could be caused by long-duration bursting in the motor neurons, which can lead to long-duration tail bends in the Mn-treated larvae. Mn-treated larvae also exhibited fewer startle movements. Additionally, we show that the intensity of tyrosine hydroxylase immunoreactivity is reversibly reduced after Mn-treatment. This led us to propose that reduced dopamine neuromodulation drives the changes in startle movements. To test this, when we supplied an external source of dopamine to Mn-treated larvae, the larvae exhibited a normal number of startle swims. Taken together, these results indicate that Mn interferes with neuronal function at the sensory, motor and modulatory levels, and open avenues for therapeutically targeted studies on the zebrafish model of manganism. PMID:25261567

Baseline blood levels of manganese, lead, cadmium, copper, and zinc in residents of Beijing suburb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Long-Lian, E-mail: Longlian57@163.com; Lu, Ling; Pan, Ya-Juan

Baseline blood concentrations of metals are important references for monitoring metal exposure in environmental and occupational settings. The purpose of this study was to determine the blood levels of manganese (Mn), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) among the residents (aged 12–60 years old) living in the suburb southwest of Beijing in China and to compare the outcomes with reported values in various developed countries. Blood samples were collected from 648 subjects from March 2009 to February 2010. Metal concentrations in the whole blood were determined by ICP-MS. The geometric means of blood levels of Mn, Cu,more » Zn, Pb and Cd were 11.4, 802.4, 4665, 42.6, and 0.68 µg/L, respectively. Male subjects had higher blood Pb than the females, while the females had higher blood Mn and Cu than the males. There was no gender difference for blood Cd and Zn. Smokers had higher blood Cu, Zn, and Cd than nonsmokers. There were significant age-related differences in blood levels of all metals studied; subjects in the 17–30 age group had higher blood levels of Mn, Pb, Cu, and Zn, while those in the 46–60 age group had higher Cd than the other age groups. A remarkably lower blood level of Cu and Zn in this population as compared with residents of other developed countries was noticed. Based on the current study, the normal reference ranges for the blood Mn were estimated to be 5.80–25.2 μg/L; for blood Cu, 541–1475 μg/L; for blood Zn, 2349–9492 μg/L; for blood Pb, <100 μg/L; and for blood Cd, <5.30 μg/L in the general population living in Beijing suburbs. - Highlights: • Baseline blood levels of metals in residents of Beijing suburb are investigated. • BMn and BPb in this cohort are higher than those in other developed countries. • Remarkably lower blood levels of Cu and Zn in this Chinese cohort are noticed. • The reference values for blood levels of Mn, Cu, Zn, Pb, and Cd are established.« less

Giant increase of critical current density and vortex pinning in Mn doped K{sub x}Fe{sub 2−y}Se{sub 2} single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Mingtao; Zhang, Jincang, E-mail: jczhang@staff.shu.edu.cn; Materials Genome Institute, Shanghai University, Shanghai 200444

2014-11-10

We report a comparative study of the critical current density (J{sub c}) and vortex pinning among pure and Mn doped K{sub x}Fe{sub 2−y}Se{sub 2} single crystals. It is found that the J{sub c} values can be greatly improved by Mn doping and post-quenching treatment when comparing to pristine pure sample. In contrast to pure samples, an anomalous second magnetization peak (SMP) effect is observed in both 1% and 2% Mn doped samples at T = 3 K for H∥ab but not for H∥c. Referring to Dew-Hughes and Kramer's model, we performed scaling analyses of the vortex pinning force density vs magnetic field inmore » 1% Mn doped and quenched pristine crystals. The results show that the normal point defects are the dominant pinning sources, which probably originate from the variations of intercalated K atoms. We propose that the large nonsuperconducting K-Mn-Se inclusions may contribute to the partial normal surface pinning and give rise to the anomalous SMP effect for H∥ab in Mn doped crystals. These results may facilitate further understanding of the superconductivity and vortex pinning in intercalated iron-selenides superconductors.« less

MnO2 nanorods/SiO2 sphere coated on single-wall carbon nanotubes as supercapacitor electrode for high energy storage applications

NASA Astrophysics Data System (ADS)

Iro, Zaharaddeen S.; Subramani, C.; Kesavan, T.; Dash, S. S.; Sasidharan, M.; Sundramoorthy, Ashok K.

2017-12-01

A composite of MnO2/SiO2 sphere was coated on single-wall carbon nanotubes (MnO2/SiO2/SWCNT) using one-pot hydrothermal synthesis method. KMnO4 was used as an oxidizing agent for mild functionalization of single-wall carbon nanotubes (SWCNT), and also as a precursor of MnO2. A comparative study in the presence of SiO2 and SWCNT was carried out using bare MnO2 as a reference. After addition of SiO2, the composite obtained showed an increase in both the specific capacitance and cycle life which can be associated with spherical shape of SiO2 which offered reduction sites for MnO2. With the addition of SWCNT less than 5%, the composite further showed an increase in capacitance and cycle life, this is because of the good conductive nature, excellent mechanical property and chemical stability of SWCNT. The electrochemical behaviour was studied using cyclic voltammetry and galvanostatic charge/discharge method in 1 M Na2SO4 electrolyte. The specific capacitance of MnO2, MnO2/SiO2 and MnO2/SiO2/SWCNT composite is 73.6 F g-1, 108.7 F g-1 and 136 F g-1 at a current density of 1 A g-1, respectively. The MnO2/SiO2/SWCNT energy density was 68 Wh kg-1 with power density of 444.4 W kg-1. The MnO2/SiO2/SWCNT composite retained 88% of its specific capacitance after 500 cycles. We envisage that this hybrid material could be applied for preparation of supercapacitor electrode.

17β-estradiol and tamoxifen protect mice from manganese-induced dopaminergic neurotoxicity.

PubMed

Pajarillo, Edward; Johnson, James; Kim, Judong; Karki, Pratap; Son, Deok-Soo; Aschner, Michael; Lee, Eunsook

2018-03-01

Chronic exposure to manganese (Mn) causes neurotoxicity, referred to as manganism, with common clinical features of parkinsonism. 17β-estradiol (E2) and tamoxifen (TX), a selective estrogen receptor modulator (SERM), afford neuroprotection in several neurological disorders, including Parkinson's disease (PD). In the present study, we tested if E2 and TX attenuate Mn-induced neurotoxicity in mice, assessing motor deficit and dopaminergic neurodegeneration. We implanted E2 and TX pellets in the back of the neck of ovariectomized C57BL/6 mice two weeks prior to a single injection of Mn into the striatum. One week later, we assessed locomotor activity and molecular mechanisms by immunohistochemistry, real-time quantitative PCR, western blot and enzymatic biochemical analyses. The results showed that both E2 and TX attenuated Mn-induced motor deficits and reversed the Mn-induced loss of dopaminergic neurons in the substantia nigra. At the molecular level, E2 and TX reversed the Mn-induced decrease of (1) glutamate aspartate transporter (GLAST) and glutamate transporter 1 (GLT-1) mRNA and protein levels; (2) transforming growth factor-α (TGF-α) and estrogen receptor-α (ER-α) protein levels; and (3) catalase (CAT) activity and glutathione (GSH) levels, and Mn-increased (1) malondialdehyde (MDA) levels and (2) the Bax/Bcl-2 ratio. These results indicate that E2 and TX afford protection against Mn-induced neurotoxicity by reversing Mn-reduced GLT1/GLAST as well as Mn-induced oxidative stress. Our findings may offer estrogenic agents as potential candidates for the development of therapeutics to treat Mn-induced neurotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

[Normal and cut-off values of the cytokinesis-block micronucleus assay on peripheral blood lymphocytes in the Croatian general population].

PubMed

Kopjar, Nevenka; Kasuba, Vilena; Milić, Mirta; Rozgaj, Ruzica; Zeljezić, Davor; Gajski, Goran; Mladinić, Marin; Garaj-Vrhovac, Vera

2010-06-01

The cytokinesis-block micronucleus (CBMN) assay on peripheral blood lymphocytes is one of the most important methods employed in cytogenetic biomonitoring. For the purposes of biological dosimetry, it is important to know the spontaneous frequency of a biomarker and its normal values in general population. These values are used for population databases, which should be updated regularly. In this study, MN levels were investigated in cytokinesis-blocked lymphocytes of 200 healthy male and female blood donors selected at random from the general population of Croatia. The aim was to assess the variability and determine possible influences of external and/or internal factors on the background levels of MN and to establish the cut-off value for the CBMN assay. The background frequency of MN was (6.90+/-3.32) MN (median 7 MN) and the range was 0 to 18 MN per 1000 binuclear lymphocytes. The cut-off value, which corresponds to 95th percentile of the distribution of 200 individual values, was 12.5 MN. Spontaneous formation of MN was influenced by sex, age, and smoking. Women had higher MN levels than men. However, only age and smoking significantly increased the values of all parameters evaluated by the CBMN assay. Since the existing literature data on smoking-related formation of MN are contradictory, we will continue these investigations to resolve how the number of cigarettes smoked per day and the duration of smoking in years influence the results of the CBMN assay. Our results are consistent with the background MN frequencies reported by other cytogenetic laboratories worldwide. Normal and cut-off values estimated in this study will be used to update the current general population data and as reference for occupationally or accidental exposure.

Neuromotor function in ship welders after cessation of manganese exposure.

PubMed

Wastensson, Gunilla; Sallsten, Gerd; Bast-Pettersen, Rita; Barregard, Lars

2012-08-01

The aim of the present study was to investigate whether previous long-term exposure to manganese (Mn) via inhalation of welding fumes can cause persistent impairment in neuromotor function even long after cessation of exposure. Quantitative tests of tremor, motor speed, manual dexterity, diadochokinesis, eye-hand coordination and postural stability were administered to 17 retired ship welders (mean age 69 years), with mean exposure time 28 years. The welders' exposure had ceased on average 18 years before the study. A cumulative exposure index (CEI) was calculated for each of the former welders. The welders were compared with 21 referents from the same shipyards (mean age was 66 years). Former welders performed less well than referents in the grooved pegboard test, and poorer performance was associated with CEI. The performance in most of the other neurobehavioral tests was similar between groups, but the welders tended to perform slightly better than the referents in tests demanding hand steadiness. The latter finding may be due to a training effect from their former working tasks or selection bias into or out of this occupation. In the present study of welders with previous welding fume exposure, former welders and referents performed similarly in most of the neurobehavioral tests. Previous adverse effects on the neuromotor system might have ceased, and decreased neuromotor function due to normal aging processes in both groups might have disguised any slight effect of previous Mn exposure. The poorer performance in the grooved pegboard test among welders may indicate an adverse effect on motor function of long-term exposure to Mn, but this finding has to be confirmed by other studies.

Environmental Exposure to Manganese in Air: Associations with Cognitive Functions

EPA Science Inventory

Manganese (Mn), an essential element, can be neurotoxic in high doses. This cross-sectional study explored the oognitive function of adults residing in two towns (Marietta and East Liverpool, Ohio, USA) identified as having high levels of environmental airborne Mn from indu...

Spreading of a Lidocaine Formulation on Microneedle-Treated Skin.

PubMed

Nayak, Atul; Das, Diganta B; Chao, Tzu C; Starov, Victor M

2015-12-01

The spreadability of a liquid drug formulation on skin is an indication of it either remaining stationary or distributing (spreading) as a droplet. Factors determining droplet spreadability of the formulation are spreading area, diameter of the droplet base, viscosity of the liquid, contact angle, volume of droplet on skin and any others. The creation of microcavities from the application of microneedle (MN) has the potential to control droplet spreading, and hence, target specific areas of skin for drug delivery. However, there is little work that demonstrates spreading of liquid drug formulation on MN-treated skin. Below, spreading of a lidocaine hydrogel formulation and lidocaine solution (reference liquid) on porcine skin is investigated over MN-treated skin. Controlled spreadability was achieved with the lidocaine hydrogel on MN-treated skin as compared with lidocaine solution. It was observed that the droplet spreading parameters such as spreading radius, droplet height and dynamic contact angle were slightly lower for the lidocaine hydrogel than the lidocaine solution on skin. Also, the lidocaine hydrogel on MN-treated skin resulted in slower dynamic reduction of droplet height, contact angle and reduced time taken in attaining static advancing droplets because of the MN microcavities. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Measurement of trace elements in tree rings using the PIXE method

NASA Astrophysics Data System (ADS)

Aoki, Toru; Katayama, Yukio; Kagawa, Akira; Koh, Susumu; Yoshida, Kohji

1998-03-01

Standard materials were prepared in order to calculate element concentrations in tree samples using the particle induced X-ray emission (PIXE) method. Five standard solutions (1) Ti, Fe, Cu, As, Rb, Sr; (2) Ca, V, Co, Zn, As, Rb; (3) Ti, Mn, Ni, As, Sr; (4) K, Mn, Co, As, Rb, Sr; and (5) Ca, Mn, Cu, As, Rb, Sr, were added to filter papers. The dried filter papers were used as standard samples. Pellets of Pepperbush leaves (National Institute for Environmental Studies (NIES)) and Peach leaves (National Institute of Standards and Technology (NIST)) were used as references. The peak counts of Ca, Mn, Cu, Zn, Rb, and Sr in samples taken from a kaki ( Diospros kaki Thunb.) were measured and the concentrations (ppm) of the elements were calculated using the yield curve obtained from the standard filter papers. The concentrations of Mn, Zn, Rb, and Ca were compared with the data obtained from a separate INAA analysis. Concentrations of Mn, Zn, and Ca obtained by both methods were almost the same, but the concentrations of Rb differed slightly. The amounts of trace elements in samples taken from a sugi ( Cryptomeria japonica D. Don) were also measured.

Variance components of short-term biomarkers of manganese exposure in an inception cohort of welding trainees.

PubMed

Baker, Marissa G; Simpson, Christopher D; Sheppard, Lianne; Stover, Bert; Morton, Jackie; Cocker, John; Seixas, Noah

2015-01-01

Various biomarkers of exposure have been explored as a way to quantitatively estimate an internal dose of manganese (Mn) exposure, but given the tight regulation of Mn in the body, inter-individual variability in baseline Mn levels, and variability in timing between exposure and uptake into various biological tissues, identification of a valuable and useful biomarker for Mn exposure has been elusive. Thus, a mixed model estimating variance components using restricted maximum likelihood was used to assess the within- and between-subject variance components in whole blood, plasma, and urine (MnB, MnP, and MnU, respectively) in a group of nine newly-exposed apprentice welders, on whom baseline and subsequent longitudinal samples were taken over a three month period. In MnB, the majority of variance was found to be between subjects (94%), while in MnP and MnU the majority of variance was found to be within subjects (79% and 99%, respectively), even when controlling for timing of sample. While blood seemed to exhibit a homeostatic control of Mn, plasma and urine, with the majority of the variance within subjects, did not. Results presented here demonstrate the importance of repeat measure or longitudinal study designs when assessing biomarkers of Mn, and the spurious associations that could result from cross-sectional analyses. Copyright © 2014 Elsevier GmbH. All rights reserved.

Exposure to Potentially Traumatic Events in Early Childhood: Differential Links to Emergent Psychopathology

ERIC Educational Resources Information Center

Briggs-Gowan, Margaret J.; Carter, Alice S.; Clark, Roseanne; Augustyn, Marilyn; McCarthy, Kimberly J.; Ford, Julian D.

2010-01-01

Research NeedsObjective: To examine associations between exposure to potentially traumatic events (PTEs) and clinical patterns of symptoms and disorders in preschool children. Method: Two hundred and thirteen referred and non-referred children, ages 24 to 48 months (MN = 34.9, SD = 6.7 months) were studied. Lifetime exposure to PTEs (family…

High-Strength Ultra-Fine-Grained Hypereutectic Al-Si-Fe-X (X = Cr, Mn) Alloys Prepared by Short-Term Mechanical Alloying and Spark Plasma Sintering.

PubMed

Průša, Filip; Bláhová, Markéta; Vojtěch, Dalibor; Kučera, Vojtěch; Bernatiková, Adriana; Kubatík, Tomáš František; Michalcová, Alena

2016-11-30

In this work, Al-20Si-10Fe-6Cr and Al-20Si-10Fe-6Mn (wt %) alloys were prepared by a combination of short-term mechanical alloying and spark plasma sintering. The microstructure was composed of homogeneously dispersed intermetallic particles forming composite-like structures. X-ray diffraction analysis and TEM + EDS analysis determined that the α-Al along with α-Al 15 (Fe,Cr)₃Si₂ or α-Al 15 (Fe,Mn)₃Si₂ phases were present, with dimensions below 130 nm. The highest hardness of 380 ± 7 HV5 was observed for the Al-20Si-10Fe-6Mn alloy, exceeding the hardness of the reference as-cast Al-12Si-1Cu-1 Mg-1Ni alloy (121 ± 2 HV5) by nearly a factor of three. Both of the prepared alloys showed exceptional thermal stability with the hardness remaining almost the same even after 100 h of annealing at 400 °C. Additionally, the compressive strengths of the Al-20Si-10Fe-6Cr and Al-20Si-10Fe-6Mn alloys reached 869 MPa and 887 MPa, respectively, and had virtually the same values of 870 MPa and 865 MPa, respectively, even after 100 h of annealing. More importantly, the alloys showed an increase in ductility at 400 °C, reaching several tens of percent. Thus, both of the investigated alloys showed better mechanical properties, including superior hardness, compressive strength and thermal stability, as compared to the reference Al-10Si-1Cu-1Mg-1Ni alloy, which softened remarkably, reducing its hardness by almost 50% to 63 ± 8 HV5.

High-Strength Ultra-Fine-Grained Hypereutectic Al-Si-Fe-X (X = Cr, Mn) Alloys Prepared by Short-Term Mechanical Alloying and Spark Plasma Sintering

PubMed Central

Průša, Filip; Bláhová, Markéta; Vojtěch, Dalibor; Kučera, Vojtěch; Bernatiková, Adriana; Kubatík, Tomáš František; Michalcová, Alena

2016-01-01

In this work, Al-20Si-10Fe-6Cr and Al-20Si-10Fe-6Mn (wt %) alloys were prepared by a combination of short-term mechanical alloying and spark plasma sintering. The microstructure was composed of homogeneously dispersed intermetallic particles forming composite-like structures. X-ray diffraction analysis and TEM + EDS analysis determined that the α-Al along with α-Al15(Fe,Cr)3Si2 or α-Al15(Fe,Mn)3Si2 phases were present, with dimensions below 130 nm. The highest hardness of 380 ± 7 HV5 was observed for the Al-20Si-10Fe-6Mn alloy, exceeding the hardness of the reference as-cast Al-12Si-1Cu-1 Mg-1Ni alloy (121 ± 2 HV5) by nearly a factor of three. Both of the prepared alloys showed exceptional thermal stability with the hardness remaining almost the same even after 100 h of annealing at 400 °C. Additionally, the compressive strengths of the Al-20Si-10Fe-6Cr and Al-20Si-10Fe-6Mn alloys reached 869 MPa and 887 MPa, respectively, and had virtually the same values of 870 MPa and 865 MPa, respectively, even after 100 h of annealing. More importantly, the alloys showed an increase in ductility at 400 °C, reaching several tens of percent. Thus, both of the investigated alloys showed better mechanical properties, including superior hardness, compressive strength and thermal stability, as compared to the reference Al-10Si-1Cu-1Mg-1Ni alloy, which softened remarkably, reducing its hardness by almost 50% to 63 ± 8 HV5. PMID:28774094

Elevated manganese and cognitive performance in school-aged children and their mothers.

PubMed

Menezes-Filho, José A; Novaes, Cristiane de O; Moreira, Josino C; Sarcinelli, Paula N; Mergler, Donna

2011-01-01

Growing evidence suggests that excess manganese (Mn) in children is associated with neurobehavioral impairments. In Brazil, elevated hair Mn concentrations were reported in children living near a ferro-manganese alloy plant. We investigated these children's and caregivers' cognitive function in relation to bioindicators of Mn exposure. In this cross-sectional study, the WISC-III was administered to 83 children aged between 6 and 12 years; the Raven Progressive Matrix was administered to the primary caregivers (94% mothers), who likewise responded to a questionnaire on socio demographics and birth history. Mn in hair (MnH) and blood (MnB) and blood lead (PbB) were measured by graphite furnace atomic absorption spectrometry (GFAAS). Children's mean MnB and MnH were 8.2 μg/L (2.7-23.4) and 5.83 μg/g (0.1-86.68), respectively. Mean maternal MnH was 3.50 μg/g (0.10-77.45) and correlated to children's MnH (rho=0.294, p=0.010). Children's MnH was negatively related to Full-Scale Intelligence Quotient (IQ) and Verbal IQ; β coefficients for MnH were -5.78 (95% CI -10.71 to -0.21) and -6.72 (-11.81 to -0.63), adjusted for maternal education and nutritional status. Maternal MnH was negatively associated with performance on the Raven's (β=-2.69, 95% CI -5.43 to 0.05), adjusted for education years, family income and age. These findings confirm that high MnH in children is associated with poorer cognitive performance, especially in the verbal domain. Primary caregiver's IQ is likewise associated to Mn exposure, suggesting that, in this situation, children's cognition may be affected directly and indirectly by Mn exposure. Copyright © 2010 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menezes-Filho, Jose A., E-mail: antomen@ufba.br; Public and Environmental Health Program, National School of Public Health, Oswaldo Cruz Foundation; Novaes, Cristiane de O.

Background: Growing evidence suggests that excess manganese (Mn) in children is associated with neurobehavioral impairments. In Brazil, elevated hair Mn concentrations were reported in children living near a ferro-manganese alloy plant. Objectives: We investigated these children's and caregivers' cognitive function in relation to bioindicators of Mn exposure. Methods: In this cross-sectional study, the WISC-III was administered to 83 children aged between 6 and 12 years; the Raven Progressive Matrix was administered to the primary caregivers (94% mothers), who likewise responded to a questionnaire on socio demographics and birth history. Mn in hair (MnH) and blood (MnB) and blood lead (PbB)more » were measured by graphite furnace atomic absorption spectrometry (GFAAS). Results: Children's mean MnB and MnH were 8.2 {mu}g/L (2.7-23.4) and 5.83 {mu}g/g (0.1-86.68), respectively. Mean maternal MnH was 3.50 {mu}g/g (0.10-77.45) and correlated to children's MnH (rho=0.294, p=0.010). Children's MnH was negatively related to Full-Scale Intelligence Quotient (IQ) and Verbal IQ; {beta} coefficients for MnH were -5.78 (95% CI -10.71 to -0.21) and -6.72 (-11.81 to -0.63), adjusted for maternal education and nutritional status. Maternal MnH was negatively associated with performance on the Raven's ({beta}=-2.69, 95% CI -5.43 to 0.05), adjusted for education years, family income and age. Conclusions: These findings confirm that high MnH in children is associated with poorer cognitive performance, especially in the verbal domain. Primary caregiver's IQ is likewise associated to Mn exposure, suggesting that, in this situation, children's cognition may be affected directly and indirectly by Mn exposure.« less

Surface Selective Oxide Reduction During the Intercritical Annealing of Medium Mn Steel

NASA Astrophysics Data System (ADS)

Jo, Kyoung Rae; Cho, Lawrence; Oh, Jong Han; Kim, Myoung Soo; Kang, Ki Cheol; De Cooman, Bruno C.

2017-08-01

Third generation advanced high-strength steels achieve an excellent strength-ductility balance using a cost-effective alloy composition. During the continuous annealing of medium Mn steel, the formation of an external selective oxide layer of MnO has a negative impact on the coating quality after galvanizing. A procedure to reduce the selective oxide was therefore developed. It involves annealing in the temperature range of 1073 K to 1323 K (800 °C to 1050 °C) in a HNx gas atmosphere. Annealing at higher temperatures and the use of larger H2 volume fractions are shown to make the gas atmosphere reducing with respect to MnO. The reduction of the surface MnO layer was observed by SEM, GDOES, and cross-sectional TEM analysis.

Use of poisons in determination of microbial manganese binding rates in seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosson, R.A.; Tebo, B.M.; Nealson, K.H.

1984-04-01

A method was developed to determine whether microorganisms mediate the precipitation of manganese(II) in the marine environment. Radioactive /sup 54/Mn(II) was used as a tracer to measure the precipitation (binding and oxidation) of Mn(II) (i.e., the /sup 54/Mn(II) trapped on 0.2-..mu..m membrane filters) in the presence and absence of biological poisons. A variety of antibiotics, fixatives, and metabolic inhibitors were tested in laboratory control experiments to select poisons that did not interfere in the chemistry of manganese. The poisons were deemed suitable if (i) they did not complex Mn(II) more strongly than the ion-exchange resin Chelex 100, (ii) they didmore » not interfere in the adsorption of /sup 54/Mn(II) onto synthetic deltaMnO/sub 2/ (manganate), (iii) they did not cause desorption of /sup 54/Mn(II) which had been preadsorbed onto synthetic manganate, and (iv) they did not solubilize synthetic /sup 54/manganate. In addition, several known chelators, reducing agents, and buffers normally added to microbiological growth media or used in biochemical assays were tested. Most additions interfered to some extent with manganese chemistry. However, at least one inhibitor, sodium azide, or a mixture of sodium azide, penicillin, and tetracycline was shown to be appropriate for use in field studies of /sup 54/Mn(II) binding. Formaldehyde could also be used in short incubations (1 to 3 h) but was not suitable for longer time course studies. The method was applied to studies of Mn(II) precipitation in Saanich Inlet, British Columbia, Canada. Bacteria were shown to significantly enhance the rate of Mn(II) removal from solution in the manganese-rich particulate layer which occurs just above the oxygen-hydrogen sulfide interface in the water column. 23 references.« less

Speciation of Mn(II), Mn(VII) and total manganese in water and food samples by coprecipitation-atomic absorption spectrometry combination.

PubMed

Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2010-01-15

A speciation procedure based on the coprecipitation of manganese(II) with zirconium(IV) hydroxide has been developed for the investigation of levels of manganese species. The determination of manganese levels was performed by flame atomic absorption spectrometry (FAAS). Total manganese was determined after the reduction of Mn(VII) to Mn(II) by ascorbic acid. The analytical parameters including pH, amount of zirconium(IV), sample volume, etc., were investigated for the quantitative recoveries of manganese(II). The effects of matrix ions were also examined. The recoveries for manganese(II) were in the range of 95-98%. Preconcentration factor was calculated as 50. The detection limit for the analyte ions based on 3 sigma (n=21) was 0.75 microg L(-1) for Mn(II). The relative standard deviation was found to be lower than 7%. The validation of the presented procedure was performed by analysis of certified reference material having different matrices, NIST SRM 1515 (Apple Leaves) and NIST SRM 1568a (Rice Flour). The procedure was successfully applied to natural waters and food samples.

Sorption of lead ions on diatomite and manganese oxides modified diatomite.

PubMed

Al-Degs, Y; Khraisheh, M A; Tutunji, M F

2001-10-01

Naturally occurring diatomaceous earth (diatomite) has been tested as a potential sorbent for Pb(II) ions. The intrinsic exchange properties were further improved by modification with manganese oxides. Modified adsorbent (referred to as Mn-diatomite) showed a higher tendency for adsorbing lead ions from solution at pH 4. The high performance exhibited by Mn-diatomite was attributed to increased surface area and higher negative surface charge after modification. Scanning electron microscope pictures revealed a birnessite structure of manganese oxides, which was featured by a plate-like-crystal structure. Diatomite filtration quality was improved after modification by manganese oxides. Good filtration qualities combined with high exchange capacity emphasised the potential use of Mn-diatomite in filtration systems.

Comparison of data transformation procedures to enhance topographical accuracy in time-series analysis of the human EEG.

PubMed

Hauk, O; Keil, A; Elbert, T; Müller, M M

2002-01-30

We describe a methodology to apply current source density (CSD) and minimum norm (MN) estimation as pre-processing tools for time-series analysis of single trial EEG data. The performance of these methods is compared for the case of wavelet time-frequency analysis of simulated gamma-band activity. A reasonable comparison of CSD and MN on the single trial level requires regularization such that the corresponding transformed data sets have similar signal-to-noise ratios (SNRs). For region-of-interest approaches, it should be possible to optimize the SNR for single estimates rather than for the whole distributed solution. An effective implementation of the MN method is described. Simulated data sets were created by modulating the strengths of a radial and a tangential test dipole with wavelets in the frequency range of the gamma band, superimposed with simulated spatially uncorrelated noise. The MN and CSD transformed data sets as well as the average reference (AR) representation were subjected to wavelet frequency-domain analysis, and power spectra were mapped for relevant frequency bands. For both CSD and MN, the influence of noise can be sufficiently suppressed by regularization to yield meaningful information, but only MN represents both radial and tangential dipole sources appropriately as single peaks. Therefore, when relating wavelet power spectrum topographies to their neuronal generators, MN should be preferred.

Estimation of the bioaccessibility and bioavailability of Fe, Mn, Cu, and Zn in Chinese vegetables using the in vitro digestion/Caco-2 cell model: the influence of gut microbiota.

PubMed

Cai, Xiaolin; Chen, Xiaochen; Yin, Naiyi; Du, Huili; Sun, Guoxin; Wang, Lihong; Xu, Yudong; Chen, Yuqing; Cui, Yanshan

2017-12-13

The influence of the human gut microbiota on the bioaccessibility and bioavailability of trace elements in vegetables has barely been studied. An in vitro digestion model combining the physiologically based extraction test (PBET) and the Simulator of Human Intestinal Microbial Ecosystem (SHIME) was applied. Results showed that the gut microbiota increased the bioaccessibility of iron (Fe) in ten test vegetables by 1.3-1.8 times, but reduced the bioaccessibility of manganese (Mn), copper (Cu), and zinc (Zn) in vegetables in the colon phase by 3.7% to 89.6%, 24.8% to 100.0%, and 59.9% to 100.0%, respectively. Using the Caco-2 cell model to simulate the human absorption process, the bioavailable contents and the bioavailability of the trace elements were further determined. Swamp cabbage was the best source of Fe and Cu; spinach and lettuce provided the highest amounts of bioavailable Mn and Zn, respectively. Referring to the daily reference intakes of trace elements, the obtained data provide a scientific basis for both reasonable ingestion of vegetables in diets and diversification of diets.

High spatial resolution analysis of ferromanganese concretions by LA-ICP-MS†

PubMed Central

Axelsson, Mikael D; Rodushkin, Ilia; Baxter, Douglas C; Ingri, Johan; Öhlander, Björn

2002-01-01

A procedure was developed for the determination of element distributions in cross-sections of ferromanganese concretions using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The effects of carrier flow rates, rf forward power, ablation energy, ablation spot size, repetition rate and number of shots per point on analyte intensity were studied. It is shown that different carrier gas flow rates are required in order to obtain maximum sensitivities for different groups of elements, thus complicating the optimisation of ICP parameters. On the contrary, LA parameters have very similar effects on almost all elements studied, thus providing a common optimum parameter set for the entire mass range. However, for selected LA parameters, the use of compromise conditions was necessary in order to compensate for relatively slow data acquisition by ICP-MS and maintain high spatial resolution without sacrificing the multielemental capabilities of the technique. Possible variations in ablation efficiency were corrected for mathematically using the sum of Fe and Mn intensities. Quantification by external calibration against matrix-matched standards was successfully used for more than 50 elements. These standards, in the form of pressed pellets (no binder), were prepared in-house using ferromanganese concentrates from a deep-sea nodule reference material as well as from shallow-marine concretions varying in size and having different proportions of three major phases: aluminosilicates, Fe- and Mn-oxyhydroxides. Element concentrations in each standard were determined by means of conventional solution nebulisation ICP-MS following acid digestion. Examples of selected inter-element correlations in distribution patterns along the cross-section of a concretion are given.

Collection of chemical-specific toxicological and pharmacokinetic data to improve risk assessments based on epidemiology: Example of Mn

EPA Science Inventory

Data limitations led to the application of default uncertainty factors in prior risk assessments for Mn. These limitations were instrumental in the EPA generation of an alternative tier II test rule under section 211 (b) of the Clean Air Act, (fuels and fuel additives) regarding ...

Interlayer Exchange Coupling: A General Scheme Turning Chiral Magnets into Magnetic Multilayers Carrying Atomic-Scale Skyrmions.

PubMed

Nandy, Ashis Kumar; Kiselev, Nikolai S; Blügel, Stefan

2016-04-29

We report on a general principle using interlayer exchange coupling to extend the regime of chiral magnetic films in which stable or metastable magnetic Skyrmions can appear at a zero magnetic field. We verify this concept on the basis of a first-principles model for a Mn monolayer on a W(001) substrate, a prototype chiral magnet for which the atomic-scale magnetic texture is determined by the frustration of exchange interactions, impossible to unwind by laboratory magnetic fields. By means of ab initio calculations for the Mn/W_{m}/Co_{n}/Pt/W(001) multilayer system we show that for certain thicknesses m of the W spacer and n of the Co reference layer, the effective field of the reference layer fully substitutes the required magnetic field for Skyrmion formation.

Segregation and microstructure evolution in chill cast and directionally solidified Ni-Mn-Sn metamagnetic shape memory alloys

NASA Astrophysics Data System (ADS)

Czaja, P.; Wierzbicka-Miernik, A.; Rogal, Ł.

2018-06-01

A multiphase solidification behaviour is confirmed for a range of Ni-rich and Ni-deficient Ni-Mn-Sn induction cast and directionally solidified (Bridgman) alloys. The composition variation is primarily linked to the changing Mn/Sn ratio, whereas the content of Ni remains largely stable. The partitioning coefficients for the Ni50Mn37Sn13 and Ni46Mn41.5Sn12.5 Bridgman alloys were obtained according to the Scheil equation based on the composition distribution along the longitudinal cross section of the ingots. Homogenization heat treatment performed for 72 h at 1220 K turned out sufficient for ensuring chemical uniformity on the macro- and microscale. It is owed to a limited segregation length scale due to slow cooling rates adopted for the directional solidification process.

A historical overview of the development of manganese (Mn) ...

EPA Pesticide Factsheets

Abstract for Manganese 2016A historical overview of the development of manganese (Mn) pharmacokinetic data under Section 211(b) of the Clean Air Act (CAA)William K BoyesBackground. In the 1990’s, the use of methylcyclopentadienyl manganese tricarbonyl (MMT) as an octane-enhancing gasoline fuel additive led to concerns for potential public health consequences from exposure to Mn combustion products in automotive exhaust. Methods: After a series of regulatory / legal actions and negotiations, the EPA issued under CAA 211(b) an Alternative Tier 2 Test Rule that required development of scientific information intended to help resolve uncertainties in exposure or health risk estimates associated with MMT use. Among the uncertainties identified were: the chemical forms of Mn emitted in automotive exhaust; the relative toxicity of different Mn species; the potential for sensitive subpopulations including females, the young and elderly; differences in sensitivity between test species and humans; differences between inhalation and oral exposures; and the influence of dose rate and exposure duration on tissue accumulation of Mn. It was determined that development of specific sets of pharmacokinetic information and models regarding Mn could help resolve much of the uncertainties identified. Results. The results of the test program included development of several unique Mn PK datasets, and a series of increasingly sophisticated Mn physiologically-based pharmacokinetic

Establishment of a reference value for chromium in the blood for biological monitoring among occupational chromium workers.

PubMed

Li, Ping; Li, Yang; Zhang, Ji; Yu, Shan-Fa; Wang, Zhi-Liang; Jia, Guang

2016-10-01

The concentration of chromium in the blood (CrB) has been confirmed as a biomarker for occupational chromium exposure, but its biological exposure indices (BEIs) are still unclear, so we collected data from the years 2006 and 2008 (Shandong Province, China) to analyze the relationship between the concentration of chromium in the air (CrA) of the workplaces and CrB to establish a reference value of CrB for biological monitoring of occupational workers. The levels of the indicators for nasal injury, kidney (β2 microglobulin (β2-MG)), and genetic damages (8-hydroxy-deoxyguanosine (8-OHdG) and micronucleus (MN)) were measured in all subjects of the year 2011 (Henan Province, China) to verify the protective effect in this reference value of CrB. Compared with the control groups, the concentrations of CrA and CrB in chromium exposed groups were significantly higher (P < 0.05). Positive correlations were found between CrA and CrB in chromium exposed groups (r 2006 = 0.60, r 2008 = 0.35) in the years 2006 and 2008. According to the occupational exposure limitation of CrA (50 μg/m(3), China), the reference value of CrB was recommended to 20 μg/L. The levels of nasal injury, β2-MG, 8-OhdG, and MN were not significantly different between the low chromium exposed group (CrB ≤ 20 μg/L) and the control group, while the levels of β2-MG, 8-OHdG, and MN were statistically different in the high chromium exposed group than that in the control group. This research proved that only in occupational workers, CrB could be used as a biomarker to show chromium exposure in the environment. The recommended reference value of CrB was 20 μg/L. © The Author(s) 2015.

Imaging of single magnetic dopants in III-V semiconductor hosts

NASA Astrophysics Data System (ADS)

Koenraad, Paul; Celebi, Cem; Silov, Andrei; Yakunin, Andrei; Tang, Jian-Ming; Flatte, Michael; Kaminska, Maria

2007-03-01

We present room-temperature cross-sectional scanning tunneling microscopy (STM) topographic measurements of the acceptor state wave function for Mn dopants in InP and compare with measurements for the nonmagnetic dopants Zn and Cd as well as with previous results for Mn in GaAs[1]. We find a strongly anisotropic ``bow-tie'' shape for the Mn acceptor state wave function in InP, similar to Mn in GaAs, which has a binding energy of 210 meV (compared to 113 meV for Mn in GaAs). The shape for Mn in InP is more symmetric with respect to the 001 plane than Mn in GaAs, which agrees with a general trend for the magnetic and nonmagnetic acceptor state symmetry as a function of acceptor binding energy. We present a new theoretical model based on the surface strain of GaAs (110) that explains why the 001-plane asymmetry of acceptor states seen in STM measurements is much larger than expected from bulk calculations. [1] A. M. Yakunin, et al., Phys. Rev. Lett. 92, 216806 (2004).

The Effect of Interface Texture on Exchange Biasing in Ni(80)Fe(20)/Ir(20)Mn(80) System.

PubMed

Chen, Yuan-Tsung

2009-01-01

Exchange-biasing phenomenon can induce an evident unidirectional hysteresis loop shift by spin coupling effect in the ferromagnetic (FM)/antiferromagnetic (AFM) interface which can be applied in magnetoresistance random access memory (MRAM) and recording-head applications. However, magnetic properties are the most important to AFM texturing. In this work, top-configuration exchange-biasing NiFe/IrMn(x A) systems have been investigated with three different conditions. From the high-resolution cross-sectional transmission electron microscopy (HR X-TEM) and X-ray diffraction results, we conclude that the IrMn (111) texture plays an important role in exchange-biasing field (H(ex)) and interfacial exchange energy (J(k)). H(ex) and J(k) tend to saturate when the IrMn thickness increases. Moreover, the coercivity (H(c)) dependence on IrMn thickness is explained based on the coupling or decoupling effect between the spins of the NiFe and IrMn layers near the NiFe/IrMn interface. In this work, the optimal values for H(ex) and J(k) are 115 Oe and 0.062 erg/cm(2), respectively.

Environmental exposure to manganese and motor function of children in Mexico.

PubMed

Hernández-Bonilla, D; Schilmann, A; Montes, S; Rodríguez-Agudelo, Y; Rodríguez-Dozal, S; Solís-Vivanco, R; Ríos, C; Riojas-Rodríguez, H

2011-10-01

Occupational manganese (Mn) exposure has been associated with motor deficits in adult workers, but data on the potential effects of environmental exposure to Mn on the developing motor function for a children population is scarce. The aim of this study was to evaluate the association between exposure to Mn and motor function of school aged children. We conducted a cross-sectional study selecting 195 children (100 exposed and 95 unexposed) between 7 and 11 years old. The following tests were used to evaluate the motor function: Grooved pegboard, finger tapping, and Santa Ana test. Mn exposure was assessed by blood (MnB) and hair concentrations (MnH). We constructed linear regression models to evaluate the association between exposure to Mn and the different test scores adjusting for age, sex, maternal education, hemoglobin and blood lead. The median concentration of MnH and MnB was significantly higher in exposed (12.6 μg/g and 9.5 μg/L) compared to unexposed children (0.6 μg/g and 8.0 μg/L). The exposed children on average performed the grooved pegboard test faster, but made more errors, although these results did not reach statistical significance with neither one of the Mn exposure biomarkers. MnB showed an inverse association on the execution of the finger tapping test (average in 5 trials β -0.4, p=0.02), but no association was observed with MnH. A subtle negative association of Mn exposure on motor speed and coordination was shown. In adults, the main effect of environmental Mn exposure has been associated with motor skills, but these results suggest that such alterations are not the main effect on children. Copyright © 2011 Elsevier Inc. All rights reserved.

Separation of nitrogen heterocyclic compounds from model coal tar fraction by solvent extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, S.J.; Chun, Y.J.

2005-07-01

The separation of four kinds of nitrogen heterocyclic compounds (NHCs) from a model mixture comprising NHCs (indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)), three kinds of bicyclic aromatic compounds (BACs; 1-methyl-naphthalene (IMN), 2-methyl naphthalene (2MN), dimethylnaphthalene (DMN)), biphenyl (Bp) and phenyl ether (Pe) was examined by a solvent extraction. The model mixture used as a raw material of this work was prepared according to the components and compositions contained in coal tar fraction (the temperature ranges of fraction: 240-265{sup o}C). An aqueous solution of methanol, ethanol, iso-propyl alcohol, N,N-dimethyl acetamide, DMF, formamide, N-methylformamide/methanol, and formamide/methanol were used as solvents.more » An aqueous solution of formamide was found suitable for separating NHCs contained in coal tar fraction based on distribution coefficient and selectivity. The effect of operation factors on separating NHCs was investigated by the distribution equilibrium using an aqueous solution of formamide. Increasing the operation temperature and the volume ratio of solvent to feed at initial (S/F)(o) resulted in improving the distribution coefficients of each NHC, but increasing the volume fraction of water in the solvent at initial (y(w,O)) resulted in deteriorating the distribution coefficients of each NHC. With increasing y(w,O) and (S/F)(o), the selectivities of each NHC in reference to DMN increased. Increase in operation temperature resulted in decrease in selectivities of each NHC in reference to DMN. At an experimental condition fixed, the sequence of the distribution coefficient and selectivity in reference to DMN for each NHC was In {gt} iQ {gt} Q {gt} Qu, and also the sequence of the distribution coefficient for each BAC was IMN {gt} 2MN {gt} DMN. The sequence of the distribution coefficient for entire compounds analyzed by this work was In {gt} iQ {gt} Q {gt} Qu {gt} BP {gt} 1MN {gt} 2MN {gt} Pe {gt} DMN.« less

Thermally stimulated properties in ZnSe:Tb and ZnSe:(Mn, Tb) phosphors

NASA Astrophysics Data System (ADS)

Mishra, A. K.; Mishra, S. K.; Pandey, S. P.; Lakshmi Mishra, Kshama

2018-02-01

Thermoluminescence studies were performed of ZnSe:Tb and ZnSe:(Mn, Tb) phosphors. A method of preparation for ZnSe phosphors doped with Tb and (Mn, Tb) has been discussed. The thermoluminescence (TL) properties of these phosphors have been studied from 100 to 370 K temperature after exciting by UV radiation (365 nm) at three uniform heating rates 0.4, 0.6 and 0.9 K/s. The trapping parameters like trap depth, lifetime of electrons and capture cross-section have also been determined using various methods.

Odontometric evaluation of mandibular premolars with tooth shape deviation: a case-control study.

PubMed

Chate, Robert Anthony Clive

2012-09-01

To evaluate the mean dimensions and morphologic characteristics of mandibular premolars that had mesiodistally elongated and faciolingually squeezed tooth shape deviations (MnP-TSD) and determine the population prevalence of this anomaly. Clinical photographs and study models were made for all new patients with MnP-TSD teeth who were seen over 20 years. The mesiodistal (MD) and faciolingual (FL) dimensions of the anomalous premolars were measured. MD/FL indices and MD × FL mm(2) occlusal crown areas were calculated and means and standard deviations were derived. Male and female means from the mandibular first and second anomalous premolars (MnP1/MnP2-TSD) were statistically compared against gender-specific means derived from published normative data using Student's t-tests and chi-square tests. Fifty-six individuals (33 male and 23 female) with MnP-TSD were identified, giving a male to female ratio of 1.4:1, while the prevalence rate in the indigenous British population was estimated to be 0.6%. The MD widths of the MnP1-TSD and MnP2-TSD teeth were approximately 1 mm wider than normal, while the FL diameters were about 0.5 mm and 1.5 mm narrower respectively, for the first and second premolar teeth. The MD/FL indices, instead of being under 90 as usual were above 100, while the mean MD/FL mm(2) crown surface areas were normal. This study supplies odontometric dimensional and morphologic data on MnP-TSD teeth that provide a reference source for future comparisons.

Microneedles: A New Frontier in Nanomedicine Delivery.

PubMed

Larrañeta, Eneko; McCrudden, Maelíosa T C; Courtenay, Aaron J; Donnelly, Ryan F

2016-05-01

This review aims to concisely chart the development of two individual research fields, namely nanomedicines, with specific emphasis on nanoparticles (NP) and microparticles (MP), and microneedle (MN) technologies, which have, in the recent past, been exploited in combinatorial approaches for the efficient delivery of a variety of medicinal agents across the skin. This is an emerging and exciting area of pharmaceutical sciences research within the remit of transdermal drug delivery and as such will undoubtedly continue to grow with the emergence of new formulation and fabrication methodologies for particles and MN. Firstly, the fundamental aspects of skin architecture and structure are outlined, with particular reference to their influence on NP and MP penetration. Following on from this, a variety of different particles are described, as are the diverse range of MN modalities currently under development. The review concludes by highlighting some of the novel delivery systems which have been described in the literature exploiting these two approaches and directs the reader towards emerging uses for nanomedicines in combination with MN.

A Newly Identified Passive Hyperaccumulator Eucalyptus grandis × E. urophylla under Manganese Stress

PubMed Central

Xie, Qingqing; Li, Zhenji; Yang, Limin; Lv, Jing; Jobe, Timothy O.; Wang, Qiuquan

2015-01-01

Manganese (Mn) is an essential micronutrient needed for plant growth and development, but can be toxic to plants in excess amounts. However, some plant species have detoxification mechanisms that allow them to accumulate Mn to levels that are normally toxic, a phenomenon known as hyperaccumulation. These species are excellent candidates for developing a cost-effective remediation strategy for Mn-polluted soils. In this study, we identified a new passive Mn-hyperaccumulator Eucalyptus grandis × E. urophylla during a field survey in southern China in July 2010. This hybrid can accumulate as much as 13,549 mg/kg DW Mn in its leaves. Our results from Scanning Electron Microscope (SEM) X-ray microanalysis indicate that Mn is distributed in the entire leaf and stem cross-section, especially in photosynthetic palisade, spongy mesophyll tissue, and stem xylem vessels. Results from size-exclusion chromatography coupled with ICP-MS (Inductively coupled plasma mass spectrometry) lead us to speculate that Mn associates with relatively high molecular weight proteins and low molecular weight organic acids, including tartaric acid, to avoid Mn toxicity. Our results provide experimental evidence that both proteins and organic acids play important roles in Mn detoxification in Eucalyptus grandis × E. urophylla. The key characteristics of Eucalyptus grandis × E. urophylla are an increased Mn translocation facilitated by transpiration through the xylem to the leaves and further distribution throughout the leaf tissues. Moreover, the Mn-speciation profile obtained for the first time in different cellular organelles of Eucalyptus grandis × E. urophylla suggested that different organelles have differential accumulating abilities and unique mechanisms for Mn-detoxification. PMID:26327118

A Newly Identified Passive Hyperaccumulator Eucalyptus grandis × E. urophylla under Manganese Stress.

PubMed

Xie, Qingqing; Li, Zhenji; Yang, Limin; Lv, Jing; Jobe, Timothy O; Wang, Qiuquan

2015-01-01

Manganese (Mn) is an essential micronutrient needed for plant growth and development, but can be toxic to plants in excess amounts. However, some plant species have detoxification mechanisms that allow them to accumulate Mn to levels that are normally toxic, a phenomenon known as hyperaccumulation. These species are excellent candidates for developing a cost-effective remediation strategy for Mn-polluted soils. In this study, we identified a new passive Mn-hyperaccumulator Eucalyptus grandis × E. urophylla during a field survey in southern China in July 2010. This hybrid can accumulate as much as 13,549 mg/kg DW Mn in its leaves. Our results from Scanning Electron Microscope (SEM) X-ray microanalysis indicate that Mn is distributed in the entire leaf and stem cross-section, especially in photosynthetic palisade, spongy mesophyll tissue, and stem xylem vessels. Results from size-exclusion chromatography coupled with ICP-MS (Inductively coupled plasma mass spectrometry) lead us to speculate that Mn associates with relatively high molecular weight proteins and low molecular weight organic acids, including tartaric acid, to avoid Mn toxicity. Our results provide experimental evidence that both proteins and organic acids play important roles in Mn detoxification in Eucalyptus grandis × E. urophylla. The key characteristics of Eucalyptus grandis × E. urophylla are an increased Mn translocation facilitated by transpiration through the xylem to the leaves and further distribution throughout the leaf tissues. Moreover, the Mn-speciation profile obtained for the first time in different cellular organelles of Eucalyptus grandis × E. urophylla suggested that different organelles have differential accumulating abilities and unique mechanisms for Mn-detoxification.

L10-MnGa based magnetic tunnel junction for high magnetic field sensor

NASA Astrophysics Data System (ADS)

Zhao, X. P.; Lu, J.; Mao, S. W.; Yu, Z. F.; Wang, H. L.; Wang, X. L.; Wei, D. H.; Zhao, J. H.

2017-07-01

We report on the investigation of the magnetic tunnel junction structure designed for high magnetic field sensors with a perpendicularly magnetized L10-MnGa reference layer and an in-plane magnetized Fe sensing layer. A large linear tunneling magnetoresistance ratio up to 27.4% and huge dynamic range up to 5600 Oe have been observed at 300 K, with a low nonlinearity of 0.23% in the optimized magnetic tunnel junction (MTJ). The field response of tunneling magnetoresistance is discussed to explain the field sensing properties in the dynamic range. These results indicate that L10-MnGa based orthogonal MTJ is a promising candidate for a high performance magnetic field sensor with a large dynamic range, high endurance and low power consumption.

Hole Concentration vs. Mn Fraction in a Diluted (Ga,Mn)As Ferromagnetic Semiconductor

DTIC Science & Technology

2002-01-01

4785 (1999). 5. T. Hayashi , M. Tanaka, and T. Nishinaga, J. App!. Ph vs. 81, 4865 (1997). 6. H. Ohno and F. Matsukura, Solid State Commnin . 117, 179...off-set between the " and I bands, and the Fermi energy (EF) increases to the right. 231 REFERENCES I . H. Ohno , H. Munekata, T. Penney, S. von Moln...r, and L. L. Chang, Phys. Rev. Lett. 68, 2664 (1992). 2. H. Ohno , A. Shen, F. Matsukura. A. Oiwa, A. Endo, S. Katsumnoto, and Y. lye, Appl. Ph vs

Opportunities to improve the in vivo measurement of manganese in human hands.

PubMed

Aslam; Chettle, D R; Pejović-Milić, A; Waker, A J

2009-01-07

Manganese (Mn) is an element which is both essential for regulating neurological and skeletal functions in the human body and also toxic when humans are exposed to excessive levels. Its excessive inhalation as a result of exposure through industrial and environmental emissions can cause neurological damage, which may manifest as memory deficit, loss of motor control and reduction in the refinement of certain body motions. A number of clinical studies demonstrate that biological monitoring of Mn exposure using body fluids, particularly blood, plasma/serum and urine is of very limited use and reflect only the most recent exposure and rapidly return to within normal ranges. In this context, a non-invasive neutron activation technique has been developed at the McMaster University accelerator laboratory that could provide an alternative to measure manganese stored in the bones of exposed subjects. In a first pilot study we conducted recently on non-exposed human subjects to measure the ratio of Mn to Ca in hand bones, it was determined that the technique needed further development to improve the precision of the measurements. It could be achieved by improving the minimum detection limit (MDL) of the system from 2.1 microg Mn/g Ca to the reference value of 0.6 microg g(-1) Ca (range: 0.16-0.78 microg Mn/g Ca) for the non-exposed population. However, the developed procedure might still be a suitable means of screening patients and people exposed to excessive amounts of Mn, who could develop many-fold increased levels of Mn in bones as demonstrated through various animal studies. To improve the MDL of the technique to the expected levels of Mn in a reference population, the present study investigates further optimization of irradiation conditions, which includes the optimal selection of proton beam energy, beam current and irradiation time and the effect of upgrading the 4pi detection system. The maximum local dose equivalent that could be given to the hand as a result of irradiation was constrained to be less than 150 mSv as opposed to the previously imposed dose equivalent limit of 20 mSv. A maximum beam current, which could be delivered on the lithium target to produce neutrons, was restricted to 500 microA. The length of irradiation intervals larger than 10 min, was considered inconvenient and impractical to implement with Mn measurements in humans. To fulfil the requirements for developing a protocol for in vivo bone Mn measurements, a revised estimate of the dose equivalent has been presented here. Beam energy of 1.98 MeV was determined to be optimal to complete the irradiation procedure within 10 min using 500 microA beam current. The local dose equivalent given to hand was estimated as 118 mSv, which is lower by a factor of 1.5 compared to that of 2.00 MeV. The optimized beam parameters are expected to improve the currently obtained detection limit of 2.1 microg Mn/g Ca to 0.6 microg Mn/g Ca. Using this dose equivalent delivered to the central location of the hand, the average dose equivalent to the hand of 74 mSv and an effective dose of approximately 70 microSv will be accompanying the non-invasive, in vivo measurements of bone Mn, which is little over the chest radiograph examination dose.

Opportunities to improve the in vivo measurement of manganese in human hands

NASA Astrophysics Data System (ADS)

Aslam; Chettle, D. R.; Pejović-Milić, A.; Waker, A. J.

2009-01-01

Manganese (Mn) is an element which is both essential for regulating neurological and skeletal functions in the human body and also toxic when humans are exposed to excessive levels. Its excessive inhalation as a result of exposure through industrial and environmental emissions can cause neurological damage, which may manifest as memory deficit, loss of motor control and reduction in the refinement of certain body motions. A number of clinical studies demonstrate that biological monitoring of Mn exposure using body fluids, particularly blood, plasma/serum and urine is of very limited use and reflect only the most recent exposure and rapidly return to within normal ranges. In this context, a non-invasive neutron activation technique has been developed at the McMaster University accelerator laboratory that could provide an alternative to measure manganese stored in the bones of exposed subjects. In a first pilot study we conducted recently on non-exposed human subjects to measure the ratio of Mn to Ca in hand bones, it was determined that the technique needed further development to improve the precision of the measurements. It could be achieved by improving the minimum detection limit (MDL) of the system from 2.1 µg Mn/g Ca to the reference value of 0.6 µg g-1 Ca (range: 0.16-0.78 µg Mn/g Ca) for the non-exposed population. However, the developed procedure might still be a suitable means of screening patients and people exposed to excessive amounts of Mn, who could develop many-fold increased levels of Mn in bones as demonstrated through various animal studies. To improve the MDL of the technique to the expected levels of Mn in a reference population, the present study investigates further optimization of irradiation conditions, which includes the optimal selection of proton beam energy, beam current and irradiation time and the effect of upgrading the 4π detection system. The maximum local dose equivalent that could be given to the hand as a result of irradiation was constrained to be less than 150 mSv as opposed to the previously imposed dose equivalent limit of 20 mSv. A maximum beam current, which could be delivered on the lithium target to produce neutrons, was restricted to 500 µA. The length of irradiation intervals larger than 10 min, was considered inconvenient and impractical to implement with Mn measurements in humans. To fulfil the requirements for developing a protocol for in vivo bone Mn measurements, a revised estimate of the dose equivalent has been presented here. Beam energy of 1.98 MeV was determined to be optimal to complete the irradiation procedure within 10 min using 500 µA beam current. The local dose equivalent given to hand was estimated as 118 mSv, which is lower by a factor of 1.5 compared to that of 2.00 MeV. The optimized beam parameters are expected to improve the currently obtained detection limit of 2.1 µg Mn/g Ca to 0.6 µg Mn/g Ca. Using this dose equivalent delivered to the central location of the hand, the average dose equivalent to the hand of 74 mSv and an effective dose of approximately 70 µSv will be accompanying the non-invasive, in vivo measurements of bone Mn, which is little over the chest radiograph examination dose.

21 CFR 184.1461 - Manganese sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Manganese sulfate. 184.1461 Section 184.1461 Food... GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O, CAS Reg. No. 7785-0987-097) is a... of pyrolusite (MnO2) ore with solid ferrous sulfate and coal, followed by leaching and...

21 CFR 184.1461 - Manganese sulfate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O, CAS... dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2) ore with solid ferrous sulfate and coal...

21 CFR 184.1461 - Manganese sulfate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O, CAS... dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2) ore with solid ferrous sulfate and coal...

33 CFR 165.927 - Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site, Duluth, MN.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site, Duluth, MN. 165.927 Section 165.927 Navigation and Navigable... Coast Guard District § 165.927 Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site...

Review of Manganese Processing for Production of TRIP/TWIP Steels, Part 1: Current Practice and Processing Fundamentals

NASA Astrophysics Data System (ADS)

Elliott, R.; Coley, K.; Mostaghel, S.; Barati, M.

2018-02-01

The increasing demand for high-performance steel alloys has led to development of transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) alloys over the past three decades. These alloys offer exceptional combinations of high tensile strength and ductility. Thus, the mechanical behavior of these alloys has been a subject of significant work in recent years. However, the challenge of economically providing Mn in the quantity and purity required by these alloys has received considerably less attention. To enable commercial implementation of ultrahigh-Mn alloys, it is desirable to lower the high material costs associated with their production. Therefore, the present work reviews Mn processing routes in the context of the chemical requirements of these alloys. The aim of this review is to assess the current state of the art regarding reduction of manganese ores and provide a comprehensive reference for researchers working to mitigate material processing costs associated with Mn production. The review is presented in two parts: Part 1 introduces TRIP and TWIP alloys, current industrial practice, and pertinent thermodynamic fundamentals; Part 2 addresses available literature regarding reduction of Mn ores and oxides, and seeks to identify opportunities for future process development.

Effect of Copper on Corrosion of Forged AlSi1MgMn Automotive Suspension Components

NASA Astrophysics Data System (ADS)

Koktas, Serhan; Gokcil, Emre; Akdi, Seracettin; Birol, Yucel

2017-09-01

Recently, modifications in the alloy composition and the manufacturing process cycle were proposed to achieve a more uniform structure with no evidence of coarse grains across the section of the AlSi1MgMn alloys. Cu was added to the AlSi1MgMn alloy to improve its age hardening capacity without a separate solution heat treatment. However, Cu addition degrades the corrosion resistance of this alloy due to the formation of Al-Cu precipitates along the grain boundaries that are cathodic with respect to the aluminum matrix and thus encourage intergranular corrosion. The present work was undertaken to identify the impact of Cu addition on the corrosion properties of AlSi1MgMn alloys with different Cu contents. A series of AlSi1MgMn alloys with 0.06-0.89 wt.% Cu were tested in order to identify an optimum level of Cu addition.

μSR study of Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} and EuMn{sub 2}O{sub 5} multiferroics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vorob’ev, S. I., E-mail: vsiloa@pnpi.spb.ru; Andrievskii, D. S.; Barsov, S. G.

2016-12-15

A comparative μSR study of ceramic samples of the EuMn{sub 2}O{sub 5} and Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} multiferroics is performed in the temperature range from 15 to 300 K. It is found that the Ce doping of the EuMn{sub 2}O{sub 5} sample slightly reduces the temperature of the magnetic phase transition from T{sub N} = 45 K for the EuMn{sub 2}O{sub 5} sample to T{sub N} = 42.5 K for the Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} sample. Below the temperature T{sub N} for both samples, there are two types of localization of a thermalized muon with different temperature dependencesmore » of the precession frequency of the magnetic moment of the muon in an internal magnetic field. The higher frequency in both samples refers to the initial antiferromagnetic matrix. The behavior of this frequency in Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} follows the Curie–Weiss law with the exponent β = 0.29 ± 0.02, which differs from the value β = 0.39 standard for 3D Heisenberg magnetics and is observed in EuMn{sub 2}O{sub 5}, because of the strong frustration of the doped sample. The temperature-independent low frequency is due to the presence of Mn{sup 3+}–Mn{sup 4+} ferromagnetic pairs located along the b axis of the antiferromagnetic matrix and in the regions of phase separation, which contain such ion pairs and e{sub g} electrons recharging them. In both samples, polarization losses are the same (about 20%) and are associated with the formation of Mn{sup 4+}–Mn{sup 4+} + Mu complexes near Mn{sup 3+}–Mn{sup 4+} ferromagnetic pairs. In the temperature interval from 25 to 45 K, the separation of the Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} structure into two fractions where the relaxation rates of polarization of muons differ by an order of magnitude is revealed. This effect is due to a change in the state of regions of phase separation (1D superlattices) at the indicated temperatures. Such effect in EuMn{sub 2}O{sub 5} is significantly weaker.« less

Cryogenic buffer-gas loading and magnetic trapping of CrH and MnH molecules

NASA Astrophysics Data System (ADS)

Stoll, Michael; Bakker, Joost M.; Steimle, Timothy C.; Meijer, Gerard; Peters, Achim

2008-09-01

We report on the buffer-gas cooling and trapping of CrH and MnH molecules in a magnetic quadrupole trap with densities on the order of 106cm-3 at a temperature of 650mK . Storage times of up to 180ms have been observed, corresponding to a 20-fold lifetime enhancement with respect to the field-free diffusion through the He3 buffer-gas. Using Monte Carlo trajectory simulations, inelastic molecule- He3 collision cross sections of 1.6×10-18 and 3.1×10-17cm2 are extracted for CrH and MnH, respectively. Furthermore, elastic molecule- He3 collision cross sections of 1.4(±0.5)×10-14cm2 are determined for both species. We conclude that the confinement time of these molecules in a magnetic trapping field is limited by inelastic collisions with the helium atoms leading to Zeeman relaxation.

New procedure of quantitative mapping of Ti and Al released from dental implant and Mg, Ca, Fe, Zn, Cu, Mn as physiological elements in oral mucosa by LA-ICP-MS.

PubMed

Sajnóg, Adam; Hanć, Anetta; Koczorowski, Ryszard; Barałkiewicz, Danuta

2017-12-01

A new procedure for determination of elements derived from titanium implants and physiological elements in soft tissues by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented. The analytical procedure was developed which involved preparation of in-house matrix matched solid standards with analyte addition based on certified reference material (CRM) MODAS-4 Cormorant Tissue. Addition of gelatin, serving as a binding agent, essentially improved physical properties of standards. Performance of the analytical method was assayed and validated by calculating parameters like precision, detection limits, trueness and recovery of analyte addition using additional CRM - ERM-BB184 Bovine Muscle. Analyte addition was additionally confirmed by microwave digestion of solid standards and analysis by solution nebulization ICP-MS. The detection limits are in range 1.8μgg -1 to 450μgg -1 for Mn and Ca respectively. The precision values range from 7.3% to 42% for Al and Zn respectively. The estimated recoveries of analyte addition line within scope of 83%-153% for Mn and Cu respectively. Oral mucosa samples taken from patients treated with titanium dental implants were examined using developed analytical method. Standards and tissue samples were cryocut into 30µm thin sections. LA-ICP-MS allowed to obtain two-dimensional maps of distribution of elements in tested samples which revealed high content of Ti and Al derived from implants. Photographs from optical microscope displayed numerous particles with µm size in oral mucosa samples which suggests that they are residues from implantation procedure. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of cation doping on the morphology, optical and structural properties of highly oriented wurtzite ZnO-nanorod arrays grown by a hydrothermal method

NASA Astrophysics Data System (ADS)

Hassanpour, A.; Guo, P.; Shen, S.; Bianucci, P.

2017-10-01

Undoped and C-doped (C: Mg2+, Ni2+, Mn2+, Co2+, Cu2+, Cr3+) ZnO nanorods were synthesized by a hydrothermal method at temperatures as low as 60 °C. The effect of doping on the morphology of the ZnO nanorods was visualized by taking their cross section and top SEM images. The results show that the size of nanorods was increased in both height and diameter by cation doping. The crystallinity change of the ZnO nanorods due to each doping element was thoroughly investigated by an x-ray diffraction (XRD). The XRD patterns show that the wurtzite crystal structure of ZnO nanorods was maintained after cation addition. The optical Raman-active modes of undoped and cation-doped nanorods were measured with a micro-Raman setup at room temperature. The surface chemistry of samples was investigated by x-ray photoelectron spectroscopy and energy-dispersive x-ray spectroscopy. Finally, the effect of each cation dopant on band-gap shift of the ZnO nanorods was investigated by a photoluminescence setup at room temperature. Although the amount of dopants (Mg2+, Ni2+, and Co2+) was smaller than the amount of Mn2+, Cu2+, and Cr3+ in the nanorods, their effect on the band structure of the ZnO nanorods was profound. The highest band-gap shift was achieved for a Co-doped sample, and the best crystal orientation was for Mn-doped ZnO nanorods. Our results can be used as a comprehensive reference for engineering of the morphological, structural and optical properties of cation-doped ZnO nanorods by using a low-temperature synthesis as an economical mass-production approach.

Impact of Food Rations and Supplements on Micronutrient Status by Trimester of Pregnancy: Cross-Sectional Studies in the Maela Refugee Camp in Thailand.

PubMed

Stuetz, Wolfgang; Carrara, Verena I; Mc Gready, Rose; Lee, Sue J; Sriprawat, Kanlaya; Po, Basi; Hanboonkunupakarn, Borimas; Grune, Tilman; Biesalski, Hans K; Nosten, François H

2016-01-26

Micronutrient fortified flour (MFF), supplementary food rations and micronutrient (MN) supplements may prevent deficiencies among pregnant women. Objectives of cross-sectional surveys in 2004 (n = 533) and 2006 (n = 515) were to assess the impact of new food rations (flour, oil) and supplements on MN status by trimester of pregnancy in the Maela refugee camp. Hemoglobin, iron status, zinc, retinol, β-carotene and tryptophan decreased, while α-/γ-tocopherol and 5-methyltetrahydrofolate (5-MTHF) increased from first to third trimester. In 2006, mean zinc and α-tocopherol for each trimester was significantly higher than in 2004. The weeks of supplemented thiamine and folic acid were positively correlated with thiamine diphosphate (TDP) and 5-MTHF, but not for ferrous sulfate as iron deficiency was observed in 38.5% of third-trimester women. Frequent consumption of fish paste and owning a garden or animal were associated with significantly higher iron status, retinol, β-carotene, and 5-MTHF. In conclusion, MFF and supplementary oil were most likely to explain improved zinc and α-tocopherol status, while thiamine and folate supplements ensured high TDP and 5-MTHF in late pregnancy. MN supplements, MN-rich staple food, small gardens, and programs to improve iron compliance are promising strategies to prevent MN deficiencies during pregnancy in vulnerable populations.

Genetics Home Reference: branchio-oculo-facial syndrome

MedlinePlus

... Bean LJH, Bird TD, Ledbetter N, Mefford HC, Smith RJH, Stephens K, editors. GeneReviews® [Internet]. Seattle (WA): ... Zori RT, Burch MN, Clemens M, Mulliken JB, Smith R, Lin AE. TFAP2A mutations result in branchio- ...

Brain magnetic resonance imaging and manganese concentrations in red blood cells of smelting workers: Search for biomarkers of manganese exposure

PubMed Central

Jiang, Yueming; Zheng, Wei; Long, Liling; Zhao, Weijia; Li, Xiangrong; Mo, Xuean; Lu, Jipei; Fu, Xue; Li, Wenmei; Liu, Shouting; Long, Quanyong; Huang, Jinli; Pira, Enrico

2014-01-01

The MRI technique has been used in diagnosis of manganism in humans and non-human primates. This cross-sectional study was designed to explore whether the pallidal signal intensity in T1-weighted MRI correlated with Mn levels in the blood compartment among Mn-exposed workers and to understand to what extent the MRI signal could reflect Mn exposure. A group of 18 randomly selected male Mn-exposed workers of which 13 were smelting workers with high exposure (mean of airborne Mn in work place: 1.26 mg/m3; range: 0.31–2.93 mg/m3), and 5 power distribution control workers with low exposure (0.66 mg/m3 and 0.23–0.77 mg/m3) from a ferroalloy factory, and another group of 9 male subjects as controls from a non-smelting factory who were office or cafeteria workers (0.01 mg/m3 and 0–0.03 mg/m3) were recruited for neurological tests, MRI examination, and analysis of Mn in whole blood (MnB), plasma (MnP) or red blood cells (MnRBC). No clinical symptoms and signs of manganism were observed among these workers. MRI data showed average increases of 7.4% (p < 0.05) and 16.1% (p < 0.01) in pallidal index (PI) among low- and high-exposed workers, respectively, as compared to controls. Fourteen out of 18 Mn-exposed workers (78%) had intensified PI values, while this proportion was even higher (85%) among the high Mn-exposed workers. Among exposed workers, the PI values were significantly associated with MnRBC (r = 0.55, p = 0.02). Our data suggest that the workers exposed to airborne Mn, but without clinical symptoms, display an exposure-related, intensified MRI signal. The MRI, as well as MnRBC, may be useful in early diagnosis of Mn exposure. PMID:16978697

Brain magnetic resonance imaging and manganese concentrations in red blood cells of smelting workers: search for biomarkers of manganese exposure.

PubMed

Jiang, Yueming; Zheng, Wei; Long, Liling; Zhao, Weijia; Li, Xiangrong; Mo, Xuean; Lu, Jipei; Fu, Xue; Li, Wenmei; Liu, Shouting; Long, Quanyong; Huang, Jinli; Pira, Enrico

2007-01-01

The MRI technique has been used in diagnosis of manganism in humans and non-human primates. This cross-sectional study was designed to explore whether the pallidal signal intensity in T1-weighted MRI correlated with Mn levels in the blood compartment among Mn-exposed workers and to understand to what extent the MRI signal could reflect Mn exposure. A group of 18 randomly selected male Mn-exposed workers of which 13 were smelting workers with high exposure (mean of airborne Mn in work place: 1.26 mg/m3; range: 0.31-2.93 mg/m3), and 5 power distribution control workers with low exposure (0.66 mg/m3 and 0.23-0.77 mg/m3) from a ferroalloy factory, and another group of 9 male subjects as controls from a non-smelting factory who were office or cafeteria workers (0.01 mg/m3 and 0-0.03 mg/m3) were recruited for neurological tests, MRI examination, and analysis of Mn in whole blood (MnB), plasma (MnP) or red blood cells (MnRBC). No clinical symptoms and signs of manganism were observed among these workers. MRI data showed average increases of 7.4% (p<0.05) and 16.1% (p<0.01) in pallidal index (PI) among low- and high-exposed workers, respectively, as compared to controls. Fourteen out of 18 Mn-exposed workers (78%) had intensified PI values, while this proportion was even higher (85%) among the high Mn-exposed workers. Among exposed workers, the PI values were significantly associated with MnRBC (r=0.55, p=0.02). Our data suggest that the workers exposed to airborne Mn, but without clinical symptoms, display an exposure-related, intensified MRI signal. The MRI, as well as MnRBC, may be useful in early diagnosis of Mn exposure.

Hierarchically mesoporous carbon nanofiber/Mn3O4 coaxial nanocables as anodes in lithium ion batteries

NASA Astrophysics Data System (ADS)

Park, Seok-Hwan; Lee, Wan-Jin

2015-05-01

Carbon nanofiber/Mn3O4 (CNF/Mn3O4) coaxial nanocables with a three-dimensional (3D) structure are prepared for lithium ion batteries by electrophoretic deposition on an electrospun CNF cathode followed by heat treatment in air. The bark-like Mn3O4 shell with a thickness of 30 nm surrounds the CNFs with a diameter of 200 nm; this hierarchically mesoporous Mn3O4 shell consisted of interconnected nanoparticles grows radially toward the CNF core when viewed from the cross-section of the coaxial cables. The charge transfer resistance of the CNF/Mn3O4 is much smaller than that of the Mn3O4 powder, because of (i) the abundant inner spaces provided via the formation of the 3D coaxial core/shell nanocables, (ii) the high electric pathway for the Mn3O4 nanoparticles attained with the 1D CNFs, and (iii) the structural stability obtained through the cushioning effect created by the CNF/Mn3O4 coaxial morphology. These unique characteristics contribute to achieving a high capacity, excellent cyclic stability, and good rate capability. The CNF/Mn3O4 nanocables deliver an initial capacity of 1690 mAh g-1 at a current density of 100 mA g-1 and maintain a high reversible capacity of 760 mAh g-1 even after 50 charge-discharge cycles without showing any obvious decay.

A new generation of high temperature oxygen sensors

NASA Astrophysics Data System (ADS)

Spirig, John V.

Potentiometric internal reference oxygen sensors were created by embedding a metal/metal oxide mixture within an yttria-stabilized zirconia oxygen-conducting ceramic superstructure. A static internal reference oxygen pressure was produced inside the reference chamber of the sensor at the target application temperature. The metal/metal oxide-containing reference chamber was sealed within the stabilized zirconia ceramic superstructure by a high pressure (3-6 MPa) and high temperature (1200-1300°C) bonding method that initiated grain boundary sliding between the ceramic components. The bonding method created ceramic joints that were pore-free and indistinguishable from the bulk ceramic. The oxygen sensor presented in this study is capable of long-term operation and is resistant to the strains of thermal cycling. The temperature ceiling of this device was limited to 800°C by the glass used to seal the sensor package where the lead wire breached the inner-to-outer environment. Were it possible to create a gas-tight joint between an electron carrier and stabilized zirconia, additional sealing agents would not be necessary during sensor construction. In order to enable this enhancement it is necessary to make a gas-tight joint between two dissimilar materials: a ceramic electrolyte and an efficient ceramic electron carrier. Aluminum-doped lanthanum strontium manganese oxide, La0.77Sr 0.20Al0.9Mn0.1O3, was joined to stabilized tetragonal zirconia polymorph YTZP (ZrO2)0.97(Y 2O3)0.03 by a uniaxial stress (3-6 MPa) and high-temperature (1250-1350°C) bonding method that initiated grain-boundary sliding between the ceramic components. An analysis of reactivity between different Al-dopings of LaxSr1-xAlyMn1-yO3 indicated that the Al:Mn ratio must be high to diminish the reaction between LaxSr1-xAlyMn1-yO3 and stabilized zirconia. While the resulting compound, La0.77Sr 0.20Al0.9Mn0.1O3, was an inefficient electron carrier, the successful bond between an aluminum-doped manganate perovskite and stabilized zirconia, served as a model system for joining electron carriers to an electrolyte without the creation of undesirable interlayers. Electron microscopy confirmed that intergranular penetration occurred at the joining plane leading to effective bonding between the two dissimilar ceramics. Raman spectral maps of the joining planes obtained with 2-D Raman microscopy demonstrated the absence of any new phases at the interface. A conducting perovskite with a lower Al:Mn ratio, but compensating A-site deficiency, La0.69Sr0.18Al0.45Mn0.55 O3, was joined to YTZP at 1250°C. X-ray diffraction was used to gain structural information on this A-site deficient perovskite. Room temperature resistivity measurements of the electroceramics were performed on joined and unjoined samples to determine the extent to which joining altered electron conduction within the LSAM. Electron microscopy confirmed that intergranular penetration occurred at the joining plane leading to effective bonding between the two dissimilar ceramics. Raman spectral maps of the joined samples demonstrated that joining temperature determines the extent to which interlayers begin to form in the joining plane. X-ray microdiffraction of the joining planes confirmed a threshold temperature for operation of a device created from these materials at 1350°C. A new material with diminished reactivity and high conductivity is presented to serve as a replacement for metal electrodes. In this manner, the model for a new generation of high-temperature oxygen sensors with internal references and ceramic wires is elucidated.

Visualization of hormone binding proteins in vivo based on Mn-doped CdTe QDs

NASA Astrophysics Data System (ADS)

Liu, Fang fei; Yu, Ying; Lin, Bi xia; Hu, Xiao gang; Cao, Yu juan; Wu, Jian zhong

2014-10-01

Daminozide (B9) is a growth inhibitor with important regulatory roles in plant growth and development. Locating and quantifying B9-binding proteins in plant tissues will assist in investigating the mechanism behind the signal transduction of B9. In this study, red fluorescent Mn-doped CdTe quantum dots (CdTeMn QDs) were synthesized by a high-temperature hydrothermal process. Since CdTeMn QDs possess a maximum fluorescence emission peak at 610 nm, their fluorescence properties are more stable than those of CdTe QDs. A B9-CdTeMn probe was synthesized by coupling B9 with CdTeMn QDs. The fluorescence intensity of the probe is double that of CdTeMn QDs; its fluorescence stability is also superior under different ambient conditions. The probe retains the biological activity of B9 and is unaffected by interference from the green fluorescent protein present in plants. Therefore, we used this probe to label B9-binding proteins selectively in root tissue sections of mung bean seedlings. These proteins were observed predominantly on the surfaces of the cell membranes of the cortex and epidermal parenchyma.

Chemical fractionation of heavy metals in urban soils of Guangzhou, China.

PubMed

Lu, Ying; Zhu, Feng; Chen, Jie; Gan, Haihua; Guo, Yanbiao

2007-11-01

Knowledge of the total concentration of heavy metals is not enough to fully assess the environmental impact of urban soils. For this reason, the determination of metal speciation is important to evaluate their environment and the mobilization capacity. Sequential extraction technique proposed by the former European Community Bureau of Reference (BCR) was used to speciate Cd, Cu, Fe, Mn, Ni, Pb, and Zn in urban soils from Guangzhou into four operationally defined fractions: HOAc extractable, reducible, oxidizable, and residual. The Cu, Fe, Ni, and Zn were predominantly located in the residual fraction, Pb in the reducible fraction, and Cd and Mn within the HOAc extractable fraction. The order of Cd in each fraction was generally HOAc extractable > reducible > residual > oxidizable; Cu and Fe were residual > reducible > oxidizable > HOAc extractable; Mn was HOAc extractable > residual > reducible > oxidizable; Ni and Zn were residual > reducible > HOAc extractable > oxidizable; and Pb was reducible > residual > oxidizable > HOAc extractable. Cadmium was identified as being the most mobile of the elements, followed by Mn, Zn, Ni, Cu, Pb and Fe. Iron-Mn oxides can play an important role in binding Cd, Cu, Ni, Pb, and Zn and in decreasing their proportion associated with the residual fraction in the soils. With total concentrations of Cd, Cu, Ni, Pb, Zn, and Mn increase, these metals more easily release and may produce more negative effects on the urban environment.

Cross sections for He and Ne isotopes in natural Mg, Al, and Si, He isotopes in CaF2, Ar isotopes in natural Ca, and radionuclides in natural Al, Si, Ti, Cr, and stainless steel induced by 12- to 45-MeV protons

NASA Technical Reports Server (NTRS)

Walton, J. R.; Heymann, D.; Yaniv, A.; Edgerley, D.; Rowe, M. W.

1976-01-01

Stacks of thin Mg, Al, Si, Ca, CaF2, Ti, and stainless steel foils were bombarded in twelve irradiations by a variable energy cyclotron. Cross sections are reported for He and Ne in natural Mg, Al, and Si, and for He in CaF2, and for Ar in natural Ca, as determined from mass spectrometer analysis of the inert gases. In addition, cross sections of Na-22 in natural Al and Si, of V-48 in natural Ti, and of Cr-51, Mn-52, and Co-57 in stainless steel are reported. From these were deduced Cr-51 and Mn-52 cross sections in natural Cr.

Characterisation of a natural quartz crystal as a reference material for microanalytical determination of Ti, Al, Li, Fe, Mn, Ga and Ge

USGS Publications Warehouse

Audetat, Andreas; Garbe-Schonberg, Dieter; Kronz, Andreas; Pettke, Thomas; Rusk, Brian G.; Donovan, John J.; Lowers, Heather

2015-01-01

A natural smoky quartz crystal from Shandong province, China, was characterised by laser ablation ICP-MS, electron probe microanalysis (EPMA) and solution ICP-MS to determine the concentration of twenty-four trace and ultra trace elements. Our main focus was on Ti quantification because of the increased use of this element for titanium-in-quartz (TitaniQ) thermobarometry. Pieces of a uniform growth zone of 9 mm thickness within the quartz crystal were analysed in four different LA-ICP-MS laboratories, three EPMA laboratories and one solution-ICP-MS laboratory. The results reveal reproducible concentrations of Ti (57 ± 4 μg g-1), Al (154 ± 15 μg g-1), Li (30 ± 2 μg g-1), Fe (2.2 ± 0.3 μg g-1), Mn (0.34 ± 0.04 μg g-1), Ge (1.7 ± 0.2 μg g-1) and Ga (0.020 ± 0.002 μg g-1) and detectable, but less reproducible, concentrations of Be, B, Na, Cu, Zr, Sn and Pb. Concentrations of K, Ca, Sr, Mo, Ag, Sb, Ba and Au were below the limits of detection of all three techniques. The uncertainties on the average concentration determinations by multiple techniques and laboratories for Ti, Al, Li, Fe, Mn, Ga and Ge are low; hence, this quartz can serve as a reference material or a secondary reference material for microanalytical applications involving the quantification of trace elements in quartz.

Structural changes in the nano-oxide layer with annealing in specular spin valves

NASA Astrophysics Data System (ADS)

Jang, S. H.; Kim, Y. W.; Kang, T.; Kim, H. J.; Kim, K. Y.

2003-05-01

We investigated microstructural changes in a nano-oxide layer (NOL) with annealing in specular spin valves (SVs) by cross-sectional transmission electron microscopy and x-ray photoelectron spectroscopy analysis. In the SV annealed at high temperature of 400 °C, an increase in thickness and a local breakdown of the NOL were observed. This local coarsening of the NOL is closely related to the formation of Mn oxides in the oxide-rich part of the NOL through Mn diffusion. Thus, the chemical structure of the NOL changes to the structure with Mn oxide-rich content after annealing.

Four reference soil and rock samples for measuring element availability in the Western Energy Regions

USGS Publications Warehouse

Crock, J.G.; Severson, R.C.

1980-01-01

Attaining acceptable precision in extractable element determinations is more difficult than in total element determinations. In total element determinations, dissolution of the sample is qualitatively checked by the clarity of the solution and the absence of residues. These criteria cannot be used for extracts. Possibilities for error are introduced in virtually every step in soil extractions. Therefore, the use of reference materials whose homogeneity and element content are reasonably well known is essential for determination of extractable elements. In this report, estimates of homogeneity and element content are presented for four reference samples. Bulk samples of about 100 kilograms of each sample were ground to pass an 80-mesh sieve. The samples were homogenized and split using a Jones-type splitter. Fourteen splits of each reference sample were analyzed for total content of Ca, Co, Cu, Fe, K, Mg, Mn, Na, and Zn; DTPA-extractable Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn; exchangeable Ca, Mg, K, and Na; cation exchange capacity water-saturation-extractable Ca, Mg, K, Na, C1, and SO4; soil pH; and hot-water-extractable boron. Error measured between splits was small, indicating that the samples were homogenized adequately and that the laboratory procedure provided reproducible results.

Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO2.

PubMed

Ozmen, Murat; Güngördü, Abbas; Erdemoglu, Sema; Ozmen, Nesrin; Asilturk, Meltem

2015-08-01

The toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO2. Undoped and Mn-doped TiO2 nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV-vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO2 was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO2 nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO2 increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2-4h of degradation. However, biochemical assays showed that both Mn-doped TiO2 and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn-doped TiO2 should be considered due to nanomaterial applications and for spilled nanoparticles in an aquatic ecosystem. Also, the risk of nanoparticles should be considered using indicator reference biochemical markers to verify the environmental health impacts. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of chromium, cobalt and manganese in biological samples (scalp hair, blood, and urine) of Pakistani viral hepatitis (A-E) patients and controls.

PubMed

Afridi, Hassan Imran; Kazi, Tasneem Gul; Kazi, Naveed; Naeemullah; Arain, Sadaf Sadia; Brahman, Kapil Dev; Wadhwa, Sham Kumar

2013-01-01

The aim of the present study was to compare the level of chromium (Cr), cobalt (Co), and manganese (Mn) in biological samples (blood, urine, and scalp hair) of patients suffering from different types of viral hepatitis (A, B, C, D, and E; n = 521) of both genders, ages ranging from 31 - 45 years. For comparative study, 255 age-matched control subjects of both genders residing in the same city were selected as referents. The digests of all biological samples were analysed for Cr, Co, and Mn by electrothermal atomic absorption spectrometry (ETAAS). The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and compared with those values obtained by conventional wet acid digestion method on same CRMs. The results of this study showed that the mean values of Cr, Co, and Mn were higher in blood and scalp hair samples of hepatitis patients than in age-matched control subjects. The urinary levels of these elements were found to be higher in the hepatitis patients than in the age-matched healthy controls (p <0.001). These results are consistent with literature-reported data, confirming that the overload of these trace elements can directly cause lipid peroxidation and eventually hepatic damage.

VizieR Online Data Catalog: A Multiplet Table for MnI (Adelman+, 1989)

NASA Astrophysics Data System (ADS)

Adelman, S. J.; Svatek, G. F.; van Winkler, K.; Warren, W. H., Jr.

1995-08-01

A Multiplet Table for Mn I was prepared by first calculating all possible transitions consistent with a change in J of 0, -1, and +1 from the atomic energy levels of Mn I (Corliss and Sugar 1977). The transitions selected for inclusion were observed lines from Cataln, Meggers, and Garcia-Riquelme (1964), Brown and Ginter (1978), and Baig, Connerade, and Newson (1979). Also included were predicted lines to complete multiplets in which one or more lines were seen by Cataln et al. (1964) and predicted multiplets contained in Kurucz and Peytremann (1975). These predicted transitions satisfy L-S coupling rules. Users should consult the source publication and the references to the original work that are cited in the bibliography at the end of this document for additional details. (2 data files).

Critical Evaluations and Thermodynamic Optimizations of the MnO-Mn2O3-SiO2 and FeO-Fe2O3-MnO-Mn2O3-SiO2 Systems

NASA Astrophysics Data System (ADS)

Kang, Youn-Bae; Jung, In-Ho

2017-06-01

A critical evaluation and thermodynamic modeling for thermodynamic properties of all oxide phases and phase diagrams in the Fe-Mn-Si-O system (MnO-Mn2O3-SiO2 and FeO-Fe2O3-MnO-Mn2O3-SiO2 systems) are presented. Optimized Gibbs energy parameters for the thermodynamic models of the oxide phases were obtained which reproduce all available and reliable experimental data within error limits from 298 K (25°C) to above the liquidus temperatures at all compositions covering from known oxide phases, and oxygen partial pressure from metal saturation to 0.21 bar. The optimized thermodynamic properties and phase diagrams are believed to be the best estimates presently available. Slag (molten oxide) was modeled using the modified quasichemical model in the pair approximation. Olivine (Fe2SiO4-Mn2SiO4) was modeled using two-sublattice model in the framework of the compound energy formalism (CEF), while rhodonite (MnSiO3-FeSiO3) and braunite (Mn7SiO_{12} with excess Mn2O3) were modeled as simple Henrian solutions. It is shown that the already developed models and databases of two spinel phases (cubic- and tetragonal-(Fe, Mn)3O4) using CEF [Kang and Jung, J. Phys. Chem. Solids (2016), vol. 98, pp. 237-246] can successfully be integrated into a larger thermodynamic database to be used in practically important higher order system such as silicate. The database of the model parameters can be used along with a software for Gibbs energy minimization in order to calculate any type of phase diagram section and thermodynamic properties.

Combined use of EPR and 23Na MAS NMR spectroscopy for assessing the properties of the mixed cobalt-nickel-manganese layers of P3-NayCo1-2xNixMnxO2.

PubMed

Kalapsazova, M; Ivanova, S; Kukeva, R; Simova, S; Wegner, S; Zhecheva, E; Stoyanova, R

2017-10-11

Knowledge on the formation of mixed transition metal layers on lithium and sodium transition metal oxides, Li/Na(Co,Ni,Mn,)O 2 , determines the ability to control their electrochemical properties as electrode materials in alkaline ion batteries. Taking this into account, herein we combine the EPR and 23 Na MAS NMR spectroscopic techniques to gain insights into the structural peculiarities of the mixed cobalt-nickel-manganese layers of Na y Co 1-2x Ni x Mn x O 2 with a three-layer stacking (P3-type) structure. Two types of compositions are examined where diamagnetic Co 3+ and paramagnetic Ni 3+ and Mn 4+ are stabilized: Na 2/3 Co 1/3 Ni 1/3 Mn 1/3 O 2 and Na 1/2 Ni 1/2 Mn 1/2 O 2 . EPR spectroscopy operating in the X- and Q-band region is applied with an aim to improve the spectra resolution and, on the other hand, to provide straightforward information on the coordination of the transition metal ions inside the layers. The analysis of EPR spectra is based on the reference for the Mn 4+ and Ni 2+ ions occurring simultaneously in oxides with two layer stacking, P2-Na 2/3 Ni 1/3 Mn 2/3 O 2 . Complementary to EPR, 23 Na MAS NMR spectroscopy at high spinning rates is undertaken to assess the local structure of the Na nucleus in the layered P3-Na y Co 1-2x Ni x Mn x O 2 oxides. All results are discussed taking into account the EPR and NMR data for the well-known lithium analogues O3-LiCo 1/3 Ni 1/3 Mn 1/3 O 2 and O3-LiNi 1/2 Mn 1/2 O 2 . Finally, the structure peculiarities of the transition metal layers extracted from the EPR and NMR methods are demonstrated by electrochemical intercalation of Li + ions into P3-Na y Co 1-2x Ni x Mn x O 2 .

Cyanide Single-Molecule Magnets Exhibiting Solvent Dependent Reversible "On" and "Off" Exchange Bias Behavior.

PubMed

Pinkowicz, Dawid; Southerland, Heather I; Avendaño, Carolina; Prosvirin, Andrey; Sanders, Codi; Wernsdorfer, Wolfgang; Pedersen, Kasper S; Dreiser, Jan; Clérac, Rodolphe; Nehrkorn, Joscha; Simeoni, Giovanna G; Schnegg, Alexander; Holldack, Karsten; Dunbar, Kim R

2015-11-18

The syntheses, structures, and magnetic properties of four new complex salts, (PPN){[Mn(III)(salphen)(MeOH)]2[M(III)(CN)6]}·7MeOH (Mn2M·7MeOH) (M = Fe, Ru, Os and Co; PPN(+) = bis(triphenylphosphoranylidene)ammonium cation; H2salphen = N,N'-bis(salicylidene)-1,2-diaminobenzene), and a mixed metal Co/Os analogue (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH were undertaken. It was found that all compounds exhibit switchable single-molecule magnet (SMM) and exchange-bias behavior depending on the interstitial methanol content. The pristine (PPN){[Mn(salphen)(MeOH)]2[Os(CN)6]}·7MeOH (Mn2Os·7MeOH) behaves as an SMM with an effective barrier for the magnetization reversal, (Ueff/kB), of 17.1 K. Upon desolvation, Mn2Os exhibits an increase of Ueff/kB to 42.0 K and an opening of the hysteresis loop observable at 1.8 K. Mn2Os·7MeOH shows also exchange-bias behavior with magnetic hysteresis loops exhibiting a shift in the quantum tunneling to 0.25 T from zero-field. The Fe(III) and Ru(III) analogues were prepared as reference compounds for assessing the effect of the 5d versus 4d and 3d metal ions on the SMM properties. These compounds are also SMMs and exhibit similar effects but with lower energy barriers. These findings underscore the importance of introducing heavy transition elements into SMMs to improve their slow relaxation of the magnetization properties. The (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)(CN)6]}·7MeOH (Mn2Co·7MeOH) analogue with a diamagnetic Co(III) central atom and the mixed Co/Os (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH (Mn2Co/Os·7MeOH) "magnetically diluted" system with a 9:1 Co/Os metal ratio were prepared in order to further probe the nature of the energy barrier increase upon desolvation of Mn2Os. In addition, inelastic neutron scattering and frequency-domain Fourier-transform THz electron paramagnetic resonance spectra obtained on Mn2Os·7MeOH and Mn2Os in combination with the magnetic data revealed the presence of anisotropic exchange interactions between Mn(III) and Os(III) ions.

Martensitic transformation in as-grown and annealed near-stoichiometric epitaxial Ni2MnGa thin films

NASA Astrophysics Data System (ADS)

Machain, P.; Condó, A. M.; Domenichini, P.; Pozo López, G.; Sirena, M.; Correa, V. F.; Haberkorn, N.

2015-08-01

Magnetic shape memory nanostructures have a great potential in the field of the nanoactuators. The relationship between dimensionality, microstructure and magnetism characterizes the materials performance. Here, we study the martensitic transformation in supported and free-standing epitaxial Ni47Mn24Ga29 films grown by sputtering on (0 0 1) MgO using a stoichiometric Ni2MnGa target. The films have a Curie temperature of ~390 K and a martensitic transition temperature of ~120 K. Similar transition temperatures have been observed in films with thicknesses of 1, 3 and 4 μm. Thicker films (with longer deposition time) present a wider martensitic transformation range that can be associated with small gradients in their chemical concentration due to the high vapour pressure of Mn and Ga. The magnetic anisotropy of the films shows a strong change below the martensitic transformation temperature. No features associated with variant reorientation induced by magnetic field have been observed. Annealed films in the presence of a Ni2MnGa bulk reference change their chemical composition to Ni49Mn26Ga25. The change in the chemical composition increases the martensitic transformation temperature, being closer to the stoichiometric compound, and reduces the transformation hysteresis. In addition, sharper transformations are obtained, which indicate that chemical inhomogeneities and defects are removed. Our results indicate that the properties of Ni-Mn-Ga thin films grown by sputtering can be optimized (fixing the chemical concentration and removing crystalline defects) by the annealing process, which is promising for the development of micromagnetic shape memory devices.

Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders

PubMed Central

Lewis, Mechelle M.; Flynn, Michael R.; Lee, Eun-Young; Van Buren, Scott; Van Buren, Eric; Du, Guangwei; Fry, Rebecca C.; Herring, Amy H.; Kong, Lan; Mailman, Richard B.; Huang, Xuemei

2016-01-01

Objectives We demonstrated recently that the T1 relaxation rate (R1) captured short-term Mn exposure in welders with chronic, relatively low exposure levels in a cross-sectional study. In the current study, we used a longitudinal design to examine whether R1 values reflect the short-term dynamics of Mn exposure. Methods Twenty-nine welders were evaluated at baseline and 12 months. Occupational questionnaires estimated short-term welding exposure using welding hours in the 90 days prior to each study visit (HrsW90). In addition, blood Mn levels, the pallidal index (PI; globus pallidus T1-weighted intensity (T1WI)/frontal white matter T1WI), and R1 values in brain regions of interest (ROIs) were determined as Mn biomarkers at each visit. Associations between changes in estimated welding exposure and changes in purported Mn biomarkers were assessed by Spearman’s correlations with adjustment for age and baseline R1, HrsW90, and blood Mn values. Results Changes in welding hours (HrsW90: the short-term welding exposure estimate), was associated significantly with changes in R1 values in the putamen (r=0.541, p=0.005), caudate (R=0.453, p=0.023), globus pallidus (R=0.430, p=0.032), amygdala (R=0.461, p=0.020), and hippocampus (R=0.447, p=0.025), but not with changes in blood Mn levels or the PI. Discussion Changes in R1 values correlated with changes in the short-term welding exposure estimate, but not with more traditional measures of Mn exposure (blood Mn levels or PI). These results suggest that R1 may serve as a useful marker to capture the short-term dynamics in Mn brain accumulation related to welding exposure. PMID:27567731

Assessment of heavy metal contamination in the sediments from the Yellow River Wetland National Nature Reserve (the Sanmenxia section), China.

PubMed

Cheng, Qingli; Wang, Ruiling; Huang, Wenhai; Wang, Wenlin; Li, Xudong

2015-06-01

The Yellow River Wetland National Nature Reserve (the Sanmenxia section) is an important area of the Yellow River for two important hydrologic gauging stations: the Sanmenxia reservoir and the Xiaolangdi reservoir. Seven sites along the section were selected: Jiziling, Dinghuwan, Houdi, Canglonghu, Shangcun, Wangguan, and Nancun. After the microwave digestion with aqua regia, concentrations of Cu, Pb, Cd, Cr, Zn, and Mn in the sediments were analyzed by flame atomic absorption spectrometry with air-acetylene flame. The results showed that all the concentrations of Cr detected were from the lithogenic source, and 63 % Mn, 48 % Pb, 41 % Cu, 20 % Cd, and 12 % Zn were from the anthropogenic source. The values of the index of geo-accumulation pointed out that there was moderate contamination of Mn at the Dinghuwan (1.04) and Houdi (1.00) sites (class 2), while the modified degree of contamination denoted that the contamination at the Houdi site (2.02) was moderate, nil to very low at the Nancun and Shangcun sites and low at the other sites, consisting with the tendency of pollution load index. For metal toxicity, the sediment pollution index indicated that the sediments of the Canglonghu site were low polluted, that of the Houdi site is nearly slightly contaminated, and those of others were natural and uncontaminated. It was vital to evaluate the degree of contamination with individual and overall elements and even with the metal toxicity. Cu, Pb, and Mn contaminations were aggravated in the Sanmenxia section, and there maybe was one of the main anthropogenic sources of these metals along the Yellow River. The findings were expected to update the current status of the heavy metal pollution in the Sanmenxia section as well as to create awareness concerning the sound condition of the whole reaches of the Yellow River.

Intellectual Function in Mexican Children Living in a Mining Area and Environmentally Exposed to Manganese

PubMed Central

Riojas-Rodríguez, Horacio; Solís-Vivanco, Rodolfo; Schilmann, Astrid; Montes, Sergio; Rodríguez, Sandra; Ríos, Camilo; Rodríguez-Agudelo, Yaneth

2010-01-01

Background Excessive exposure to manganese (Mn), an essential trace element, has been shown to be neurotoxic, especially when inhaled. Few studies have examined potential effects of Mn on cognitive functions of environmentally exposed children. Objective This study was intended to estimate environmental exposure to Mn resulting from mining and processing and to explore its association with intellectual function of school-age children. Methods Children between 7 and 11 years of age from the Molango mining district in central Mexico (n = 79) and communities with similar socioeconomic conditions that were outside the mining district (n = 93) participated in the cross-sectional evaluation. The revised version of the Wechsler Intelligence Scale for Children adapted for the Mexican population was applied. Concentrations of Mn in blood (MnB) and hair (MnH) were used as biomarkers of exposure. Results Exposed children had significantly higher median values for MnH (12.6 μg/g) and MnB (9.5 μg/L) than did nonexposed children (0.6 μg/g and 8.0 μg/L, respectively). MnH was inversely associated with Verbal IQ [β = −0.29; 95% confidence interval (CI), −0.51 to −0.08], Performance IQ (β = −0.08; 95% CI, −0.32 to 0.16), and Total Scale IQ (β = −0.20; 95% CI, −0.42 to 0.02). MnB was inversely but nonsignificantly associated with Total and Verbal IQ score. Age and sex significantly modified associations of MnH, with the strongest inverse associations in young girls and little evidence of associations in boys at any age. Associations with MnB did not appear to be modified by sex but appeared to be limited to younger study participants. Conclusions The findings from this study suggest that airborne Mn environmental exposure is inversely associated with intellectual function in young school-age children. PMID:20936744

Intellectual function in Mexican children living in a mining area and environmentally exposed to manganese.

PubMed

Riojas-Rodríguez, Horacio; Solís-Vivanco, Rodolfo; Schilmann, Astrid; Montes, Sergio; Rodríguez, Sandra; Ríos, Camilo; Rodríguez-Agudelo, Yaneth

2010-10-01

Excessive exposure to manganese (Mn), an essential trace element, has been shown to be neurotoxic, especially when inhaled. Few studies have examined potential effects of Mn on cognitive functions of environmentally exposed children. This study was intended to estimate environmental exposure to Mn resulting from mining and processing and to explore its association with intellectual function of school-age children. Children between 7 and 11 years of age from the Molango mining district in central Mexico (n = 79) and communities with similar socioeconomic conditions that were outside the mining district (n = 93) participated in the cross-sectional evaluation. The revised version of the Wechsler Intelligence Scale for Children adapted for the Mexican population was applied. Concentrations of Mn in blood (MnB) and hair (MnH) were used as biomarkers of exposure. Exposed children had significantly higher median values for MnH (12.6 μg/g) and MnB (9.5 μg/L) than did nonexposed children (0.6 μg/g and 8.0 μg/L, respectively). MnH was inversely associated with Verbal IQ [β = -0.29; 95% confidence interval (CI), -0.51 to -0.08], Performance IQ (β = -0.08; 95% CI, -0.32 to 0.16), and Total Scale IQ (β = -0.20; 95% CI, -0.42 to 0.02). MnB was inversely but nonsignificantly associated with Total and Verbal IQ score. Age and sex significantly modified associations of MnH, with the strongest inverse associations in young girls and little evidence of associations in boys at any age. Associations with MnB did not appear to be modified by sex but appeared to be limited to younger study participants. The findings from this study suggest that airborne Mn environmental exposure is inversely associated with intellectual function in young school-age children.

Highly conductive electrospun carbon nanofiber/MnO2 coaxial nano-cables for high energy and power density supercapacitors

NASA Astrophysics Data System (ADS)

Zhi, Mingjia; Manivannan, Ayyakkannu; Meng, Fanke; Wu, Nianqiang

2012-06-01

This paper presents highly conductive carbon nanofiber/MnO2 coaxial cables in which individual electrospun carbon nanofibers are coated with an ultrathin hierarchical MnO2 layer. In the hierarchical MnO2 structure, an around 4 nm thick sheath surrounds the carbon nanofiber (CNF) in a diameter of 200 nm, and nano-whiskers grow radically outward from the sheath in view of the cross-section of the coaxial cables, giving a high specific surface area of MnO2. The CNFs are synthesized by electrospinning a precursor containing iron acetylacetonate (AAI). The addition of AAI not only enlarges the specific surface area of the CNF but also greatly enhances their electronic conductivity, which leads to a dramatic improvement in the specific capacitance and the rate capability of the CNF/MnO2 electrode. The AAI-CNF/MnO2 electrode shows a specific capacitance of 311 F g-1 for the whole electrode and 900 F g-1 for the MnO2 shell at a scan rate of 2 mV s-1. Good cycling stability, high energy density (80.2 Wh kg-1) and high power density (57.7 kW kg-1) are achieved. This work indicates that high electronic conductivity of the electrode material is crucial to achieving high power and energy density for pseudo-supercapacitors.

Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

NASA Astrophysics Data System (ADS)

Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

2016-08-01

Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

Pure MnTBAP selectively scavenges peroxynitrite over superoxide: Comparison of pure and commercial MnTBAP samples to MnTE-2-PyP in two different models of oxidative stress injuries, SOD-specific E. coli model and carrageenan-induced pleurisy

PubMed Central

Batinić-Haberle, Ines; Cuzzocrea, Salvatore; Rebouças, Júlio S.; Ferrer-Sueta, Gerardo; Mazzon, Emanuela; Di Paola, Rosanna; Radi, Rafael; Spasojević, Ivan; Benov, Ludmil; Salvemini, Daniela

2009-01-01

MnTBAP is often referred to as an SOD mimic in numerous models of oxidative stress. We have recently reported that pure MnTBAP does not dismute superoxide, but commercial/ill-purified samples are able to perform O2•− dismutation with low-to-moderate efficacy via non-innocent Mn-containing impurities. Herein, we show that neither commercial nor pure MnTBAP could substitute for SOD enzyme in the SOD-deficient E. coli model, while MnTE-2-PyP-treated SOD-deficient E. coli grew as well as wild-type strain. This SOD-specific system indicates that MnTBAP does not act as an SOD mimic in vivo. In another model, carrageenan-induced pleurisy in mice, inflammation was evidenced by increased pleural fluid exudate, and neutrophil infiltration and activation: these events were blocked by 0.3 mg/kg of MnTE-2-PyP and to a slightly lesser extent with 10 mg/kg of MnTBAP. Also, 3-nitrotyrosine formation, an indication of the peroxynitrite existence in vivo, was blocked by both compounds; again MnTE-2-PyP was 33-fold more effective. Pleurisy model data indicate that MnTBAP exert some protective actions in common with MnTE-2-PyP, which are not O2•−-related, and can be fully rationalized if one considers that the common biological role shared by MnTBAP and MnTE-2-PyP is related to their reduction of peroxynitrite and carbonate radical, the latter arising from ONOO− adduct with CO2. The log kcat (O2•−) value for MnTBAP is estimated to be about 3.16, which is ~5 and ~7 orders of magnitude smaller than the SOD activity of the potent SOD mimic MnTE-2-PyP and Cu, Zn-SOD, respectively. This very low value indicates that MnTBAP is very inefficient in dismuting superoxide to be of any biological impact, which was confirmed in the SOD-deficient E. coli model. Peroxynitrite scavenging ability of MnTBAP, however, is only ~2.5 orders of magnitude smaller than that of MnTE-2-PyP and is not significantly affected by the presence of the SOD-active impurities in commercial MnTBAP sample (log kred(ONOO−) = 5.06 for pure and 4.97 for commercial sample). The reduction of carbonate radical is equally fast with MnTBAP and MnTE-2-PyP. The dose of MnTBAP required to yield oxidative stress protection and block nitrotyrosine formation in the pleurisy model is >1.5 orders of magnitude higher than that of MnTE-2-PyP, which could be related to the smaller ability of MnTBAP to scavenge peroxynitrite. The slightly better protection observed with the commercial MnTBAP sample (relative to the pure MnTBAP one) could arise from its impurities, which, by scavenging O2•−, reduce consequently the overall peroxynitrite, and secondary ROS/RNS levels. These observations have profound biological repercussions as they may suggest that the effect of MnTBAP observed in numerous studies may conceivably relate to peroxynitrite scavenging. Moreover, provided that pure MnTBAP is unable to dismute superoxide at any significant extent, but is able to partially scavenge peroxynitrite and carbonate radical, this compound may prove valuable to distinguish ONOO−/CO3•− from O2•− pathways. PMID:19007878

6. Detail of interior bin wall section, during demolition. Shows ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Detail of interior bin wall section, during demolition. Shows alternating courses of channel tile with steel bands and largers hollow tile. - Saint Anthony Elevator No. 3, 620 Malcom Avenue, Southeast, Minneapolis, Hennepin County, MN

Level density and mechanism of deuteron-induced reactions on Fe 54 , 56 , 58

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramirez, A. P. D.; Voinov, A. V.; Grimes, S. M.

Here, deuteron elastic cross sections, as well as neutron, proton, and α-particle emission spectra, from d+ 54,56,58Fe reactions have been measured with deuteron beam energies of 5, 7, and 9 MeV. Optical model parameters have been tested against our experimental data. The fraction of total reaction cross section responsible for the formation of compound nuclei has been deduced from the angular distributions. The degree of discrepancy between calculated and experimental compound cross sections was found to increase with increasing neutron number. The nuclear level densities of the residual nuclei 55Co, 57Co, 55Fe, 57Fe, 52Mn, and 54Mn have been deduced frommore » the compound double differential cross sections. The Gilbert-Cameron model with Iljinov parameter systematics [A. S. Iljinov and M. V. Mebel, Nucl. Phys. A 543, 517 (1992)] was found to have a good agreement with our results.« less

Level density and mechanism of deuteron-induced reactions on Fe 54 , 56 , 58

DOE PAGES

Ramirez, A. P. D.; Voinov, A. V.; Grimes, S. M.; ...

2015-07-06

Here, deuteron elastic cross sections, as well as neutron, proton, and α-particle emission spectra, from d+ 54,56,58Fe reactions have been measured with deuteron beam energies of 5, 7, and 9 MeV. Optical model parameters have been tested against our experimental data. The fraction of total reaction cross section responsible for the formation of compound nuclei has been deduced from the angular distributions. The degree of discrepancy between calculated and experimental compound cross sections was found to increase with increasing neutron number. The nuclear level densities of the residual nuclei 55Co, 57Co, 55Fe, 57Fe, 52Mn, and 54Mn have been deduced frommore » the compound double differential cross sections. The Gilbert-Cameron model with Iljinov parameter systematics [A. S. Iljinov and M. V. Mebel, Nucl. Phys. A 543, 517 (1992)] was found to have a good agreement with our results.« less

Blood and urinary levels of metals and metalloids in the general adult population of Northern France: The IMEPOGE study, 2008-2010.

PubMed

Nisse, Catherine; Tagne-Fotso, Romuald; Howsam, Mike; Richeval, Camille; Labat, Laurence; Leroyer, Ariane

2017-04-01

The assessment of human chemical risks related to occupational or environmental exposure to pollutants requires the use of both accurate exposure indicators and reference values. The objective of this study was to evaluate the blood and urinary levels of various metals and metalloids in a sample of adults aged 20-59 years of the general population of Northern France, a formerly heavily industrialised area that retains some industrial activity. A cross-sectional study was conducted between 2008 and 2010, enrolling 2000 residents of Northern France. The quota method was used to guarantee the representativeness of the participants on a sex, age, social category and smoking status basis, according to the census done by the French National Institute of Statistics and Economic Studies. The levels of 14 metals: aluminium (Al), antimony (Sb), total arsenic (As), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), thallium (Tl), vanadium (V) and zinc (Zn) were quantified by ICP-MS in urine and blood samples. A total of 982 men and 1018 women participated, allowing the analysis of 1992 blood and 1910 urine samples. Some metal(loid)s were detected in over 99% of the blood (Cd, Co, Mn, Ni, Pb) and urine (As, Co, Pb, Zn) samples and the remaining metals in 84-99% of the samples, with the exception of blood V (19%), blood Be (57%) and urine Be (58%). Mean blood levels of Pb and Zn were significantly higher in men, and Mn, Co and Cr in women. In urine, mean Pb, Tl and Sb concentrations were significantly higher in men, and Al and Co in women. Current smokers had significantly higher mean levels of blood Cd and Pb and lower blood Co, Mn and Hg. In urine (adjusted on urinary creatinine), the smokers had higher mean levels of Cd, Pb, V and Zn and lower mean levels of As, Co, and Hg. Overall, the mean urinary levels of most metal(loid)s found in the general population of Northern France were higher than those found in the French national survey for the same period except for urinary V. Mean blood lead level was markedly less than that of the French national population. This first biomonitoring survey of a large number of metal(loid)s in the general population of Northern France provides useful information on exposure levels to toxic elements and highlights the specificity of the regional environment. These data could be used, in complement to the national human biomonitoring reference values, for the interpretation of biomonitoring results. Copyright © 2016 Elsevier GmbH. All rights reserved.

Zeeman relaxation of MnH (X7Σ+) in collisions with He3: Mechanism and comparison with experiment

NASA Astrophysics Data System (ADS)

Turpin, F.; Stoecklin, T.; Halvick, Ph.

2011-03-01

We present a theoretical study of the Zeeman relaxation of the magnetically trappable lowest field seeking state of MnH (7Σ) in collisions with He3. We analyze the collisional Zeeman transition mechanism as a function of the final diatomic state and its variation as a function of an applied magnetic field. We show that as a result of this mechanism the levels with ΔMj>2 give negligible contributions to the Zeemam relaxation cross section. We also compare our results to the experimental cross sections obtained from the buffer-gas cooling and magnetic trapping of this molecule and investigate the dependence of the Zeeman relaxation cross section on the accuracy of the three-body interaction at ultralow energies.

Effects of Low MN Perturbation on Last Good Surface

NASA Astrophysics Data System (ADS)

Casas, Micaela; Ali, Halima; Punjabi, Alkesh

2003-10-01

This project explores the effects of low MN perturbation on last good magnetic surface (LGS) in single-null divertor tokamak. Punjabi and Boozer developed Simple Map (SM)/1/to represent cross-sections of field line trajectories in phase space. SM with low MN perturbation is given by: X_n+1=X_n-kY_n(1-δ_LowMNs(frac2π nN_p)-Y_n) and Y_n+1=Y_n-k(1-δ_LowMNs(frac2π nN_p))X_n+1 /2/ where δ_LowMN is amplitude of perturbation and Np is fixed at 10. We fix map parameter k at 0.6. By varying δ_LowMN we determine when and how LGS breaks up and becomes chaotic. We begin graphs with small increments in δ_LowMN. We observe no significant changes in LGS until δ_LowMN is more than 4.9x10-9, then it progresses to chaos in five stages. The paper will present these LGS results in depth. This research is done under mentorship of Drs. H. Ali and A. Punjabi. NASA SHARP and US DOE grant number DE-FG02-02ER54673 support the project. 1. Punjabi A. et al, Phys. Rev. Lett., 69, 3322 (1992) 2. Punjabi A. et al, Phys Plasmas, 4, 337 (1997)

Research on Spectroscopy, Opacity, and Atmospheres

NASA Astrophysics Data System (ADS)

Kurucz, Robert L.

1996-01-01

The main accomplishment was the merging of all the atomic line data into one wavelength-sorted list that is simple to use. We have combined all the atomic files from a CDROM into 534,910 line files GFALL.DAT and GFELEN.DAT. These are the data we use to compute spectra. They are not up to date. References are given in GFALL.REF or GFELEK.REF. There are no references after 1988, and for light elements there are no references after 1979. One new development is the inclusion of hyperfine splitting for the iron group elements using hyperfine data from the literature through 1993. The data are very incomplete. We have supplied a program for splitting the line list for a species. It reads the hyperfine and isotopic splitting parameters for levels and computes the splittings whenever those levels appear. Lines with no splitting data are copied untouched. Because Sc, Mn, and Co are monoisotopic, only the hyperfine splittings are needed. Since 51V is much more abundant than 50V, the isotope shifts are small for 51V, and we approximate V with 51V. GFALLHYP.DAT has 754,946 lines including hyperfine Sc I, V I, Mn I, and Co I.

Thermal and damping behaviour of magnetic shape memory alloy composites

NASA Astrophysics Data System (ADS)

Glock, Susanne; Michaud, Véronique

2015-06-01

Single crystals of ferromagnetic shape memory alloys (MSMA) exhibit magnetic field and stress induced strains via energy dissipating twinning. Embedding single crystalline MSMA particles into a polymer matrix could thus produce composites with enhanced energy dissipation, suitable for damping applications. Composites of ferromagnetic, martensitic or austenitic Ni-Mn-Ga powders embedded in a standard epoxy matrix were produced by casting. The martensitic powder composites showed a crystal structure dependent damping behaviour that was more dissipative than that of austenitic powder or Cu-Ni reference powder composites and than that of the pure matrix. The loss ratio also increased with increasing strain amplitude and decreasing frequency, respectively. Furthermore, Ni-Mn-Ga powder composites exhibited an increased damping behaviour at the martensite/austenite transformation temperature of the Ni-Mn-Ga particles in addition to that at the glass transition temperature of the epoxy matrix, creating possible synergetic effects.

Charge localization and ordering in A 2 Mn 8 O 16 hollandite group oxides: Impact of density functional theory approaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaltak, Merzuk; Fernandez-Serra, Marivi; Hybertsen, Mark S.

The phases of A 2Mn 8O 16 hollandite group oxides emerge from the competition between ionic interactions, Jahn-Teller effects, charge ordering, and magnetic interactions. Their balanced treatment with feasible computational approaches can be challenging for commonly used approximations in density functional theory. Three examples (A = Ag, Li, and K) are studied with a sequence of different approximate exchange-correlation functionals. Starting from a generalized gradient approximation (GGA), an extension to include van der Waals interactions and a recently proposed meta-GGA are considered. Then local Coulomb interactions for the Mn 3d electrons are more explicitly considered with the DFT + Umore » approach. Finally, selected results from a hybrid functional approach provide a reference. Results for the binding energy of the A species in the parent oxide highlight the role of van der Waals interactions. Relatively accurate results for insertion energies can be achieved with a low-U and a high-U approach. In the low-U case, the materials are described as band metals with a high-symmetry, tetragonal crystal structure. In the high-U case, the electrons donated by A result in formation of local Mn 3+ centers and corresponding Jahn-Teller distortions characterized by a local order parameter. The resulting degree of monoclinic distortion depends on charge ordering and magnetic interactions in the phase formed. The reference hybrid functional results show charge localization and ordering. Comparison to low-temperature experiments of related compounds suggests that charge localization is the physically correct result for the hollandite group oxides studied here. Lastly, while competing effects in the local magnetic coupling are subtle, the fully anisotropic implementation of DFT + U gives the best overall agreement with results from the hybrid functional.« less

Charge localization and ordering in A 2 Mn 8 O 16 hollandite group oxides: Impact of density functional theory approaches

DOE PAGES

Kaltak, Merzuk; Fernandez-Serra, Marivi; Hybertsen, Mark S.

2017-12-01

The phases of A 2Mn 8O 16 hollandite group oxides emerge from the competition between ionic interactions, Jahn-Teller effects, charge ordering, and magnetic interactions. Their balanced treatment with feasible computational approaches can be challenging for commonly used approximations in density functional theory. Three examples (A = Ag, Li, and K) are studied with a sequence of different approximate exchange-correlation functionals. Starting from a generalized gradient approximation (GGA), an extension to include van der Waals interactions and a recently proposed meta-GGA are considered. Then local Coulomb interactions for the Mn 3d electrons are more explicitly considered with the DFT + Umore » approach. Finally, selected results from a hybrid functional approach provide a reference. Results for the binding energy of the A species in the parent oxide highlight the role of van der Waals interactions. Relatively accurate results for insertion energies can be achieved with a low-U and a high-U approach. In the low-U case, the materials are described as band metals with a high-symmetry, tetragonal crystal structure. In the high-U case, the electrons donated by A result in formation of local Mn 3+ centers and corresponding Jahn-Teller distortions characterized by a local order parameter. The resulting degree of monoclinic distortion depends on charge ordering and magnetic interactions in the phase formed. The reference hybrid functional results show charge localization and ordering. Comparison to low-temperature experiments of related compounds suggests that charge localization is the physically correct result for the hollandite group oxides studied here. Lastly, while competing effects in the local magnetic coupling are subtle, the fully anisotropic implementation of DFT + U gives the best overall agreement with results from the hybrid functional.« less

Exposure assessment of heavy metals in an e-waste processing area in northern Vietnam.

PubMed

Oguri, Tomoko; Suzuki, Go; Matsukami, Hidenori; Uchida, Natsuyo; Tue, Nguyen Minh; Tuyen, Le Huu; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke; Takigami, Hidetaka

2018-04-15

In developing countries, inappropriate recycling of e-waste has resulted in the environmental release of toxicants, including heavy metals, that may have deleterious health effects. In this study, we estimated daily metal intakes in five households in a Vietnamese village located in an e-waste processing area and assessed the health risk posed by exposure to the metals. Garden soil, floor dust, 24-h duplicate diet, and ambient air samples were collected from five households in northern Vietnam in January 2014. All samples were acid-digested, and contents of Cd, Cu, Mn, Pb, Sb, and Zn were measured by using ICP mass spectrometry and ICP atomic emission spectroscopy. In addition, the soil, dust, and diet samples were subjected to an bioaccessibility extraction test to determine bioaccessible metal concentrations. Hazard quotients were estimated from bioaccessible metal concentrations, provisional tolerable weekly intakes, and reference doses. Garden soil and floor dust were estimated to be mainly contributors to daily Pb intake, as indicated by calculations using bioaccessible metal concentrations and the U.S. Environmental Protection Agency soil plus dust ingestion rate. Diet was suggested to contribute significantly to daily Cd, Cu, Mn, Sb, and Zn intake. Estimated metal exposures via inhalation were negligible, as indicated by calculations using International Atomic Energy Agency reference inhalation rates. The maximum hazard quotients were calculated as 0.2 (Cd), 0.09 (Cu), 0.3 (Mn), 0.6 (Pb), 0.2 (Sb), and 0.5 (Zn), on the basis of bioaccessible metal concentrations. The contributions of Cd, Cu, Mn, Sb, and Zn except Pb to potential noncancer risk for adult residents of the five households in the e-waste processing area may be low. Copyright © 2017 Elsevier B.V. All rights reserved.

Charge localization and ordering in A2Mn8O16 hollandite group oxides: Impact of density functional theory approaches

NASA Astrophysics Data System (ADS)

Kaltak, Merzuk; Fernández-Serra, Marivi; Hybertsen, Mark S.

2017-12-01

The phases of A2Mn8O16 hollandite group oxides emerge from the competition between ionic interactions, Jahn-Teller effects, charge ordering, and magnetic interactions. Their balanced treatment with feasible computational approaches can be challenging for commonly used approximations in density functional theory. Three examples (A = Ag, Li, and K) are studied with a sequence of different approximate exchange-correlation functionals. Starting from a generalized gradient approximation (GGA), an extension to include van der Waals interactions and a recently proposed meta-GGA are considered. Then local Coulomb interactions for the Mn 3 d electrons are more explicitly considered with the DFT + U approach. Finally, selected results from a hybrid functional approach provide a reference. Results for the binding energy of the A species in the parent oxide highlight the role of van der Waals interactions. Relatively accurate results for insertion energies can be achieved with a low-U and a high-U approach. In the low-U case, the materials are described as band metals with a high-symmetry, tetragonal crystal structure. In the high-U case, the electrons donated by A result in formation of local Mn3 + centers and corresponding Jahn-Teller distortions characterized by a local order parameter. The resulting degree of monoclinic distortion depends on charge ordering and magnetic interactions in the phase formed. The reference hybrid functional results show charge localization and ordering. Comparison to low-temperature experiments of related compounds suggests that charge localization is the physically correct result for the hollandite group oxides studied here. Finally, while competing effects in the local magnetic coupling are subtle, the fully anisotropic implementation of DFT + U gives the best overall agreement with results from the hybrid functional.

[Source identification and potential ecological hazards assessment of trace metalloid/heavy metals in the soil of Tianshan Mountains, Xinjiang, China].

PubMed

Zhang, Zhao-Yong; Jilili, Abuduwailil; Jiang, Feng-Qing

2014-11-01

In this study, the contents of ten metalloid/heavy metals (As, Pb, Ni, Cd, Co, Hg, Cu, Mn, Zn and Cr) in soil samples collected from three sections including the central Urumqi-Akesu, eastern Blikun-Yiwu and western Zhaosu-Tekesi in Tianshan Mountains were determined, and their sources were identified by using typical statistical and multivariate statistical methods. The potential ecological risks of these heavy metals were assessed by employing pollution index method, potential ecological risk index and the background values of Tianshan Mountains, and Xinjiang, and also the Second National Standard of the Soil Qualities of China. The results showed that the contents of the heavy metals (Pb, Ni, Cd, Co, Hg, Cu, Mn Zn and Cr) and metalloid As were all higher than the soil background values of the Tianshan Mountain or Xinjiang, and their variation co- efficients belonged to the medium variation. In general, the contents of the ten metalloid/heavy metals in the soil of Tianshan Mountains were low. Principal component analysis showed that the ten metalloid/heavy metals could be identified as two principal components, among which PC1 (Cd, Pb, Hg, Mn and Zn) could be seen as 'human influence sources factor', PC2 (Cu, Ni, Cr, Co and As) as 'natural sources factor'. Mn and As had larger loads both in PC1 and PC2, and they could be co-influenced by human and natural sources. The pollution assessment showed that Hg and Cd in central Urumuqi-Akesu section and As in western Zhaosu-Tekesi section were all at alert level, while the other heavy metals in other sections were all at security level. From the comprehensive pollution indices (P(z)) of heavy metals, it was found that the ten metalloid/heavy metals in the soils of central Urumqi-Akesu section were at low pollution level, but those in the other two sections were at clean level. The potential ecological risk assessment showed that the potential ecological risk coefficient (E(i)r) and the ecological damage index (RI) of Hg and Cd in central Urumqi-Akesu section and that of As in western Zhaosu-Tekesi section were relatively high.

Assessment of genotoxicity associated with hydroxyurea therapy in children with sickle cell anemia

PubMed Central

Flanagan, Jonathan M.; Howard, Thad A.; Mortier, Nicole; Avlasevich, Svetlana L.; Smeltzer, Matthew P.; Wu, Song; Dertinger, Stephen D.; Ware, Russell E.

2018-01-01

Hydroxyurea induces fetal hemoglobin, improves laboratory parameters, and ameliorates clinical complications of sickle cell anemia (SCA), but its long-term efficacy and safety in this patient population remain incompletely defined. Although generally considered non-DNA reactive, an important safety concern is that hydroxyurea may indirectly cause genotoxic damage. To better address this safety issue of hydroxyurea in patients with SCA, we measured the production of micronuclei (MN) in red blood cells (RBC) as a marker of genotoxicity. Blood samples were collected from children with SCA enrolled in the Hydroxyurea Study of Long-term Effects (ClinicalTrials.gov NCT00305175). Flow cytometry quantified circulating MN-containing erythrocyte sub-populations before and during hydroxyurea exposure. The frequency of micronucleated reticulocytes (MN-CD71+) and micronucleated mature erythrocytes (MN-RBC) were then tested for associations with laboratory and clinical data. In cross-sectional analysis of 293 blood samples from 105 children with SCA and a median of 2 years of hydroxyurea therapy, exposure to hydroxyurea was associated with significantly increased frequencies of MN-CD71+ and MN-RBC compared to baseline. The increases were evident by 3 months of therapy, and did not escalate further with up to 12 years of continuous drug exposure. In prospective longitudinal analysis, substantial inter-individual variation in the effect of hydroxyurea on %MN-CD71+ was observed that was associated with the expected laboratory effects of hydroxyurea. In conclusion, clinically relevant exposure to hydroxyurea is associated with increased MN production consistent with erythroblast genotoxicity but with substantial inter-patient variability. Associations between increased %MN-CD71+ and laboratory benefits suggest that hydroxyurea effects on MN production may be related to individual patient sensitivity to hydroxyurea within the bone marrow. PMID:20230905

Soft chemical synthesis and electrochemical properties of calcium ferrite-type LixMn2O4

NASA Astrophysics Data System (ADS)

Mamiya, Mikito; Tokiwa, Kazuyasu; Akimoto, Junji

2016-04-01

Calcium ferrite (CaFe2O4)-type LixMn2O4 was prepared via high-pressure and soft chemical synthesis method. The framework structure of CaFe2O4-type NaMn2O4 was synthesized from the stoichiometric mixture of Na2CO3 and MnO2 annealed by 1273 K for 1 h under 4.5 GPa. Na/Li ion-exchange of the CaFe2O4-type NaMn2O4 was carried out by soaking molten LiNO3 at 633 K for 12 h. The electrochemical properties of the ion-exchanged CaFe2O4-type LixMn2O4 were measured. The initial discharge profile in the voltage range from 4.0 to 1.0 V showed 458 mAh g-1 of the discharge capacity with two plateaus near 3.7 V and 2.7 V (vs. Li/Li+). The discharge capacity was decreased with increasing the cycle number. After 30 cycles, the capacity was decreased to 375 mAh g-1. When the range was set between 4.8 and 3.0 V, the discharge capacity was 113 mAh g-1 in initial, and 111 mAh g-1 after 50th cycle. The reference CaFe2O4-type LiMn2O4 was prepared via one-step high-pressure synthesis and compared the electrochemical properties with the ion-exchanged sample. The initial discharge capacity of the one-step synthesized one was 108 mAh g-1 at 1.0 V (vs. Li/Li+), which was 73% lower than the value of the ion-exchanged one.

The extrinsic and intrinsic apoptotic pathways are involved in manganese toxicity in rat astrocytoma C6 cells.

PubMed

Alaimo, Agustina; Gorojod, Roxana M; Kotler, Mónica L

2011-08-01

Manganese (Mn) is a trace element known to be essential for maintaining the proper function and regulation of many biochemical and cellular reactions. However, chronic exposure to high levels of Mn in occupational or environmental settings can lead to its accumulation in the brain resulting in a degenerative brain disorder referred to as Manganism. Astrocytes are the main Mn store in the central nervous system and several lines of evidence implicate these cells as major players in the role of Manganism development. In the present study, we employed rat astrocytoma C6 cells as a sensitive experimental model for investigating molecular mechanisms involved in Mn neurotoxicity. Our results show that C6 cells undergo reactive oxygen species-mediated apoptotic cell death involving caspase-8 and mitochondrial-mediated pathways in response to Mn. Exposed cells exhibit typical apoptotic features, such as chromatin condensation, cell shrinkage, membrane blebbing, caspase-3 activation and caspase-specific cleavage of the endogenous substrate poly (ADP-ribose) polymerase. Participation of the caspase-8 dependent pathway was assessed by increased levels of FasL, caspase-8 activation and Bid cleavage. The involvement of the mitochondrial pathway was demonstrated by the disruption of the mitochondrial membrane potential, the opening of the mitochondrial permeability transition pore, cytochrome c release, caspase-9 activation and the increased mitochondrial levels of the pro-apoptotic Bcl-2 family proteins. In addition, our data also shows for the first time that mitochondrial fragmentation plays a relevant role in Mn-induced apoptosis. Taking together, these findings contribute to a deeper elucidation of the molecular signaling mechanisms underlying Mn-induced apoptosis. Copyright © 2011 Elsevier B.V. All rights reserved.

44. East tile gauge on south pier. Each square tile ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. East tile gauge on south pier. Each square tile is 4' in size. Top left section of 4' square eagle section - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

47. East tile gauge on south pier. Each square tile ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

47. East tile gauge on south pier. Each square tile is 4' in size. Middle right section of 4' square eagle section - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

46. East tile gauge on south pier. Each square tile ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

46. East tile gauge on south pier. Each square tile is 4' in size. Lower right section of 4' square eagle section - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

45. East tile gauge on south pier. Each square tile ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

45. East tile gauge on south pier. Each square tile is 4' in size. Lower left section of 4' square eagel section - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

26. GRAINELEVATOR SECTION, SECOND FLOOR, INTERIOR, DETAIL OF GRAIN CRIB ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. GRAIN-ELEVATOR SECTION, SECOND FLOOR, INTERIOR, DETAIL OF GRAIN CRIB FRAMING; ELECTRICAL EQUIPMENT IS MOUNTED ON WHAT WAS ONCE THE INTERIOR OF BIN NUMBER NINE; LOOKING SOUTHEAST - Standard Mill, 116-118 Portland Avenue South, Minneapolis, Hennepin County, MN

Interpreting the paleo-redox record: Mn enrichment factors

NASA Astrophysics Data System (ADS)

Chun, C. O.; Delaney, M. L.

2006-12-01

Redox-sensitive metal enrichment factors (EF), have the ability to describe the redox chemistry of the overlying water and marine sediments at time of burial. Manganese (Mn) precipitates as Mn-rich oxyhydroxides in oxic environments, leading to sedimentary EF > 1 calculated relative to average continental crust as the presumed detrital source. Mn EF can also occur from source changes that are unrelated to redox changes. We compared bulk sediment digestions to sample splits treated with a reductive cleaning step prior to sediment digestion, to test whether the Mn EF are from oxyhydroxides. We measured sedimentary Mn EF for the past 30 m.y. for a Nazca Ridge site in the southeast Pacific (ODP Site 1237). The site is marked by a pronounced color change at 162 mcd, within an interval dominated by calcareous-rich lithology, prompting questions of source versus paleo-redox changes. Mn EF were measured across the Paleocene-Eocene Thermal Maximum (PETM) at three sites on Walvis Ridge in the southeast Atlantic (ODP Sites 1262, 1266, and 1263). The PETM global warming event leads to questions of redox changes. At Nazca Ridge Mn EF range from 10-70 prior to the change with decrease to crustal averages after the boundary. After two reductive cleanings on sediments exhibiting Mn EF >1, Mn EF were at crustal averages. Mn EF prior to the color change are oxyhydroxides and not a major input of detrital material. We suggest the color change represents a paleo-redox boundary, more oxygenated depositional setting prior to the change and more reducing depositional setting afterwards. Walvis Ridge PETM sections exhibit Mn EF values ranging between 4 and 12 prior to the warming, values at crustal averages during the warming, return to pre-event values in the recovery period. After the reductive cleaning procedure the deep (1262) and intermediate (1266) sites with Mn EF >1 before and after the warming event reduced to crustal averages with no change to Mn EF during the event. Bottom waters at those two sites were most likely oxygenated prior to the event, reducing at the onset of the warming, and returned to pre-event conditions in the recovery. Future studies of Mn EF as a paleo-redox indicator should include the reductive cleaning procedure to verify Mn-oxyhydroxides.

90. Photographic copy of plan of bins, section of boot, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

90. Photographic copy of plan of bins, section of boot, and photograph of construction originally published in Plans of Grain Elevators (Chicago; Grain Dealers Journal, 1918), p.53. PLAN OF BINS; SECTION OF BOOT; VIEW OF CONSTRUCTION LOOKING NORTHWEST - Northwestern Consolidated Elevator "A", 119 Fifth Avenue South, Minneapolis, Hennepin County, MN

Effects from environmental Mn exposures: a review of the evidence from non-occupational exposure studies.

PubMed

Hudnell, H K

1999-01-01

The risk posed to human health by environmental manganese exposure is unknown. Occupational-exposure outcomes may not extrapolate to environmental exposures due to the healthy worker effect and differences in dosage parameters which may affect the biological response. This paper attempts to combine the existing literature on non-occupational Mn exposures with results from our current study in SW Quebec on environmental Mn exposure (Mergler et al., this issue) within the framework of a biologically-based, dose-response (BBDR) model. BBDR MODEL: The basic BBDR model consists of seven stages relating exposure to health effects. The stages are: 1) sources, 2) applied dose, 3) absorbed dose, 4) target-site dose, 5) toxic event, 6) measurable change, and 7) health outcome. Several air monitoring programs, such as the PTEAM study (Riverside, CA, 1990, mean PM10 Mn outdoor-airborne 24 h average = 0.045 microgram/m3), provided data relevant to the estimation of Mn applied dose, but did not include measures of body burden. Data from the SW Quebec study showed a mean total-particulate airborne Mn concentration of 0.022 microgram/m3 with a range of 0.009 to 0.035 microgram/m3 across four sampling sites, whereas the EPA reference concentration (RfC) is 0.05 microgram/m3. EPA has considered tap water levels to be safe below 200 micrograms/l Mn, and mean Mn tap-water (MnW) level in the participants' homes was 6.38 +/- 11.95 micrograms/l with a range from 0.1 to 158.9 micrograms/l Mn. A previous study of MnW exposure in Greece reported Mn levels in areas with low, medium and high MnW ranging from 4 to 2,300 micrograms/l and a significant association with Mn in hair but not Mn in blood (MnB). The mean absorbed dose of the SW Quebec study participants, as indicated by MnB, was 7.5 +/- 2.3 micrograms/l with a range of 2.5 to 15.9 micrograms/l. Our study and others on environmental Mn exposure did not provide an estimate of target-site dose. However, a significant correlation (r = 0.65) between MnB and signal intensity in T1-weighted MRI images has been reported in liver-disease patients with Parkinson-like signs who had MnB levels as low as 6.6 micrograms/l. Only animal and in vitro studies have provided evidence on the mechanisms of toxicity caused by Mn in the CNS. Several studies reported measurable changes in endpoints suggestive of a Parkinson-like syndrome in subjects with MnB levels ranging from 7.5 to 25.0 micrograms/l. Among other effects on neurobehavioral function observed in the current study was a significant relationship between MnB and the direction and speed of body-sway in men. The effects observed in these participants are sub-clinical and no health outcomes have been diagnosed. However, the Parkinson's disease incidence in the study area was previously reported to be 2-5 times higher than in the rest of Quebec, and several studies indicate that 25-35% of idiopathic Parkinson disease diagnoses are incorrect. Our study, the Greek study, and some clinical studies suggest that the risk of a Parkinson-like syndrome diagnosis may increase with continued Mn exposure and aging. The limited data available for the BBDR model point to the need for evidence, particularly on relationships between Mn species, exposure route, MnB with chronic environmental exposure, ageing, and susceptibility factors, to improve human-health risk assessments for chronic, environmental Mn exposure.

Cognitive Function Related to Environmental Exposure to ...

EPA Pesticide Factsheets

Background: The towns of Marietta and East Liverpool (EL), Ohio, have been identified as having elevated manganese (Mn) in air due to industrial pollution. Objectives: To evaluate relationships between environmental Mn (Mn-air) exposure and distance from the source and cognitive function in residents of two Ohio towns. Methods: Data were obtained from an EPA-sponsored study comparing two towns exposed to Mn-air (Marietta and EL). A cross-sectional design was used. The same inclusion/exclusion criteria and procedures were applied in the two towns. A neuropsychological screening test battery was administered to study participants (EL=86, Marietta=100) which included Stroop Color Word Test, Animal Naming, Auditory Consonant Trigrams (ACT) and Rey-O. To estimate Mn-air, U.S.EPA’s AERMOD dispersion model was used. Distance from source was calculated based on participants’ residential address and air miles from industrial facility emitting Mn-air. A binary logistic regression model controlling for annual household income was used to examine distance from source and neuropsychological outcomes Results: There were no age, sex, or employment status differences between the two towns. Years education was lower in EL (mean (M)=12.9) than Marietta (M=14.6) and years residency in town were higher in EL (M=47.0) than Marietta (M=36.1). EL participants resided closer to the Mn source than Marietta (M=1.12 vs M=4.75 air miles). Mn-air concentrations were higher in EL (M=0

Multi-scale analysis of the occurrence of Pb, Cr and Mn in the NIST standards: Urban dust (SRM 1649a) and indoor dust (SRM 2584)

NASA Astrophysics Data System (ADS)

Jiang, Mingyu; Nakamatsu, Yuki; Jensen, Keld A.; Utsunomiya, Satoshi

2014-01-01

Adverse health effects of ambient particulate matters are closely related to the speciation of the constituting organic matters and toxic metals. To determine multi-parameters of the metal speciation in urban and indoor dusts, we have performed systematic bulk- to nano-scale (“multi-scale”) analysis on the speciation of Pb, Mn, and Cr in two National Institute of Standards and Technology (NIST) standard reference materials (SRMs): urban dust (SRM 1649a) and indoor dust (SRM 2584), utilizing X-ray absorption near-edge structure, powder X-ray diffraction analysis, electron microprobe analysis, scanning electron microscopy, and transmission electron microscopy. Major crystalline phases are quartz, gypsum, kaolinite, and muscovite in SRM 1649a, while quartz, gypsum, calcite, and possibly muscovite (or chabazite) in SRM 2584. A number of Pb sulfate nanoparticles (50-200 nm) occur in SRM 1649a, whereas micron-sized Pb carbonate is present containing various concentrations of Zn and Ti in the complex texture in SRM 2584. Relatively soluble Mn(II) sulfate is the bulk-averaged Mn speciation in SRM 1649a, although discrete Mn sulfate particles are not characterized by individual particle analysis, implying the diluted Mn distribution within other sulfate. In SRM 2584, Mn speciation includes a mixture of oxides and carbonates, and trace Mn in chromite. Chromite (FeCr2O4) is the major Cr speciation in SRM1694a, while unidentified Cr(III) phases with minor chromite and Pb chromate are present in SRM 2584, among which the Pb chromate is composed of Cr(VI). A significant number of the metal-bearing particles are distributed to the submicron-size fraction in the urban dust, SRM 1649a, suggesting that these metal nanoparticles can potentially penetrate into the deep respiratory system. This study demonstrates that multi-scale analysis combining nano and bulk analytical techniques is a powerful approach to investigate the multi-parameters of metal-bearing nanoparticles in heterogeneous PM samples.

Correct Requirements, A Factor for Success in Major Acquisition Programs

DTIC Science & Technology

2008-06-01

23 See Organizational Behavior, Mc Shane/von Glinow, Mc Graw -Hill/Irwin, New York 2007, chapter 14. 24 As stated during MN3304 class...57 LIST OF REFERENCES Apte, Aruna. (2006). Spiral Development: A perspective.NPS-GSBPP-05-009. Banus, Stephen P. (1997). Financing contingency

Manganese in Drinking Water and Cognitive Abilities and Behavior at 10 Years of Age: A Prospective Cohort Study.

PubMed

Rahman, Syed Moshfiqur; Kippler, Maria; Tofail, Fahmida; Bölte, Sven; Hamadani, Jena Derakhshani; Vahter, Marie

2017-05-26

Cross-sectional studies have indicated impaired neurodevelopment with elevated drinking water manganese concentrations (W-Mn), but potential susceptible exposure windows are unknown. We prospectively evaluated the effects of W-Mn, from fetal life to school age, on children's cognitive abilities and behavior. We assessed cognitive abilities and behavior in 1,265 ten-year-old children in rural Bangladesh using the Wechsler Intelligence Scale for Children (WISC-IV) and the Strengths and Difficulties Questionnaire (SDQ), respectively. Manganese in drinking water used during pregnancy and by the children at 5 y and 10 y was measured using inductively coupled plasma mass spectrometry. The median W-Mn was 0.20 mg/L (range 0.001–6.6) during pregnancy and 0.34mg/L (<0.001–8.7) at 10 y. In multivariable-adjusted linear regression analyses, restricted to children with low arsenic (As) exposure, none of the W-Mn exposures was associated with the children’s cognitive abilities. Stratifying by gender (p for interaction in general <0.081) showed that prenatal W-Mn (3 mg/L) was positively associated with cognitive ability measures in girls but not in boys. W-Mn at all time points was associated with an increased risk of conduct problems, particularly in boys (range 24–43% per mg/L). At the same time, the prenatal W-Mn was associated with a decreased risk of emotional problems [odds ratio (OR)=0.39 (95% CI: 0.19, 0.82)] in boys. In girls, W-Mn was mainly associated with low prosocial scores [prenatal W-Mn: OR=1.48 (95% CI: 1.06, 1.88)]. Elevated prenatal W-Mn exposure was positively associated with cognitive function in girls, whereas boys appeared to be unaffected. Early life W-Mn exposure appeared to adversely affect children's behavior. https://doi.org/10.1289/EHP631.

Cross section measurements of radiative KL2,3 RRS in 24Cr and L3M4,5 RRS in 59Pr for Mn Kα1,2 X-rays

NASA Astrophysics Data System (ADS)

Sharma, Veena; Upmanyu, Arun; Singh, Ranjit; Singh, Gurjot; Sharma, Hitesh; Kumar, Sanjeev; Mehta, D.

2017-06-01

The KL2,3 and L3M4,5 radiative resonant Raman scattering (RRS) cross sections have been measured for the quasimonochromatic Mn Kα1,2 X-rays (5.895 keV) in 24Cr (K-shell level width (ΓK) =1.08 eV) and 59 Pr (L3-subshell level width (ΓL3) =3.60 eV), respectively, using targets in metallic and various chemical forms. The incident Mn Kα1,2 X-ray energy is lower than the K-shell binding energy of 24Cr and L3-subshell binding energy of 59Pr by 94 ΓK (Cr) and 94 ΓL3 (Pr), respectively. The experimental measurements were performed with a low energy Ge detector (LEGe) and a radioactive 55Fe annular source in conjunction with 24Cr absorber. The measured cross section values for the 24Cr and 59 Pr elements in their various oxidation states are found to be same within experimental errors. The measurements were further extended to investigate alignment of the intermediate L3-subshell (J =3/2) virtual vacancy states in 59Pr through angular distribution measurements for RRS photon emission, which is found to be isotropic within experimental errors.

Use the results of measurements on KBR facility for testing of neutron data of main structural materials for fast reactors

NASA Astrophysics Data System (ADS)

Koscheev, Vladimir; Manturov, Gennady; Pronyaev, Vladimir; Rozhikhin, Evgeny; Semenov, Mikhail; Tsibulya, Anatoly

2017-09-01

Several k∞ experiments were performed on the KBR critical facility at the Institute of Physics and Power Engineering (IPPE), Obninsk, Russia during the 1970s and 80s for study of neutron absorption properties of Cr, Mn, Fe, Ni, Zr, and Mo. Calculations of these benchmarks with almost any modern evaluated nuclear data libraries demonstrate bad agreement with the experiment. Neutron capture cross sections of the odd isotopes of Cr, Mn, Fe, and Ni in the ROSFOND-2010 library have been reevaluated and another evaluation of the Zr nuclear data has been adopted. Use of the modified nuclear data for Cr, Mn, Fe, Ni, and Zr leads to significant improvement of the C/E ratio for the KBR assemblies. Also a significant improvement in agreement between calculated and evaluated values for benchmarks with Fe reflectors was observed. C/E results obtained with the modified ROSFOND library for complex benchmark models that are highly sensitive to the cross sections of structural materials are no worse than results obtained with other major evaluated data libraries. Possible improvement in results by decreasing the capture cross section for Zr and Mo at the energies above 1 keV is indicated.

Phase transition temperatures and magnetic entropy change in Ni-Mn-In-B based Heusler alloys

NASA Astrophysics Data System (ADS)

Pathak, Arjun; Gautam, Bhoj; Dubenko, Igor; Ali, Naushad

2008-03-01

One of the aspects of great attention of Heusler alloys is the large value of magnetic entropy change (δSM) and their possible application as a working material in magnetocaloric effect based magnetic refrigerators. It was reported earlier that Ni50Mn34.8In15.2 has first order martensitic transition temperature TM 212K, Curie temperature of austenitic phase TC 328K and δSM value associated with TM and TC are respectively 13 and -7 J/kg K [1]. In the present study, we are reporting the effect of partial substitution of In by B in Ni50Mn34.8In15.2 by AC susceptibility, thermal expansion, and magnetization measurements. We observed that substitution of boron sharply increase TM, and significantly enhance the δSM peak value higher than 30 J/kg K at TM 296K; however the δSM value remains almost same at TC. Therefore, the Ni-Mn-In-B based Heusler alloys will be potential material for the study of room temperature magnetic refrigerator materials. Reference: [1] A. K. Pathak, M. Khan, I. Dubenko, S. Stadler, and N. Ali, Appl. Phys. Lett. 90, 262504 (2007).

Magnetism and electronic structure at the interface of a metal CaRuO3 and Mott insulator CaMnO3.

NASA Astrophysics Data System (ADS)

Boris, Alexander; Freeland, John; Kavich, Jerald; Lee, Ho Nyung; Yordanov, Petar; Khaliullin, Giniyat; Keimer, Bernhard; Chakhalian, Jak

2007-03-01

Recent advances in fabrication of ultra-thin complex oxide heterostructures have opened new opportunities to investigate possible novel quantum states at the correlated interfaces. With this aim we fabricated ultra-thin superlattices of CaMnO3(CMO)/CaRuO3(CRO) with the thickness of CRO layers from 1 to 12 unit cells by laser MBE. Electronic properties of CRO/CMO were investigated by soft x-ray spectroscopies at the L-edges of Mn and Ru. SQUID and optical reflectivity revealed a ferromagnetic thickness-independent transition at Tc 100K and CRO thickness-dependent negative magnetoresistance. This behavior is in marked contrast to the individual layers. At the interface we found a clear sign of net magnetic moment on Mn, which saturates only at magnetic field of 5T. Unlike CMO, similar measurements at the Ru L3-edge showed no detectable magnetism in the field up to 5T. Comparison with Ru references confirmed Ru(IV) oxidation state. These findings are in the sharp contrast with previously suggested models involving Ru(IV-V) valency exchange and thus reveal intricate nature of the interface between a metal and Mott insulator.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Bohang; Li, Wangda; Yan, Pengfei

A facile synthesis method was developed to prepare xLi 2MnO 3·(1-x)LiNi 0.7Co 0.15Mn 0.15O 2 (x = 0, 0.03, 0.07, 0.10, 0.20, and 0.30 as molar ratio) cathode materials, combining the advantages of high specific capacity from Ni-rich layered phase and surface chemical stability from Li-rich layered phase. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM) and electrochemical charge/discharge performance confirm the formation of a Li-rich layered phase with C2/m symmetry. Most importantly, high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) reveals a spatial relationship that Li-rich nano-domain islands are integrated into a conventional Ni-rich layered matrix (Rmore » $$\\bar{3}$$m). This is the first time that Li-rich phase has been directly observed inside a particle at the nano-scale, when the overall composition of layered compounds (Li 1+δNi xMn yM 1-x-y-δO 2, M refers to transition metal elements) is Ni-rich (x > 0.5) rather than Mn-rich (y > 0.5). Remarkably, xLi 2MnO 3·(1-x)LiNi 0.7Co 0.15Mn 0.15O 2 cathode with optimized x value shows superior electrochemical performance at C/3, i.e., 170 mA h g -1 with 90.3 % of capacity retention after 400 cycles at 25 °C and 164 mA h g -1 with 81.3 % capacity retention after 200 cycles at 55 °C.« less

Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

USGS Publications Warehouse

Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

1999-01-01

The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep-ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

Modeling of Mn/Road test sections with the CRREL mechanistic pavement design procedure

DOT National Transportation Integrated Search

1996-09-01

The U.S. Army Cold Regions Research and Engineering Laboratory is developing a mechanistic pavement design procedure for use in seasonal frost areas. The procedure was used to predict pavement performance of some test sections under construction at t...

Does Science Presuppose Naturalism (or Anything at All)?

ERIC Educational Resources Information Center

Fishman, Yonatan I.; Boudry, Maarten

2013-01-01

Several scientists, scientific institutions, and philosophers have argued that science is committed to Methodological Naturalism (MN), the view that science, by virtue of its methods, is limited to studying "natural" phenomena and cannot consider or evaluate hypotheses that refer to supernatural entities. While they may in fact exist, gods,…

Control of Vibration in Mechanical Systems Using Shaped Reference Inputs

DTIC Science & Technology

1988-01-01

damping with several discrete actuators. Burke and Hubbard 34! generated a distributed control law by applying a piezoelectric film to the beam that...setpoints from successive memory locations. DATA-kYOVE (- starts servoing to setpoints from successive memory locations for mnicro scified by MN while taking

Genetics Home Reference: ocular albinism

MedlinePlus

... Available from http://www.ncbi.nlm.nih.gov/books/NBK1343/ Citation on PubMed Oetting WS. New insights into ocular albinism type 1 (OA1): Mutations and polymorphisms of the OA1 gene. Hum Mutat. 2002 Feb;19(2):85-92. Review. Citation on PubMed Tak WJ, Kim MN, Hong ...

Radioactivities induced in some LDEF samples

NASA Technical Reports Server (NTRS)

Reedy, Robert C.; Moss, Calvin E.

1992-01-01

Final activities are reported for gamma ray emitting isotopes measured in 35 samples from LDEF. In 26 steel trunnion samples, activities of Mn-54 and Co-57 were measured and limits set on other isotopes. In five Al end support retainer plates and two Al keel plate samples, Na-22 was measured. In two Ti clip samples, Na-22 was measured, limits for Sc-46 were obtained, and high activities for impurity Uranium and daughter isotopes were observed. Four sets of depth vs activity profiles were measured for the D sections of the trunnion. For all 4 profiles, the activities first decreased with increasing distance from the surface of the trunnion but were fairly flat near the center. These profiles are consistent with production by both the lower energy (approx. 100 MeV) trapped particles and high energy (approx. 10 GeV) galactic-cosmic ray particles. For the near surface samples, the earth quadrant had more Mn-54 than the space quadrant. For the D sections, there was less Mn-54 in the east trunnion than in the west trunnion. Comparisons are made among the samples and with activities measured by others. The limit for Sc-46 in the Ti clips is compared with the activities of Mn-54 produced in the steel pieces by similar reactions. Activities predicted by several models are compared with the measured activities.

Biomonitoring of 33 Elements in Blood and Urine Samples from Coastal Populations in Sanmen County of Zhejiang Province.

PubMed

Zhang, Su-jing; Luo, Ru-xin; Ma, Dong; Zhuo, Xian-yi

2016-04-01

To determine the normal reference values of 33 elements, Ag, Al, As, Au, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, Li, Mg, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, Th, Ti, Tl, U, V, Zn and Zr, in the blood and urine samples from the general population in Sanmen County of Zhejiang province, a typical coastal area of eastern China. The 33 elements in 272 blood and 300 urine samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The normality test of data was conducted using SPSS 17.0 Statistics. The data was compared with other reports. The normal reference values of the 33 elements in the blood and urine samples from the general population in Sanmen County were obtained, which of some elements were found to be similar with other reports, such as Co, Cu, Mn and Sr, while As, Cd, Hg and Pb were generally found to be higher than those previously reported. There was a wide variation between the reports from different countries in blood Ba. The normal reference values of the 33 elements in the blood and urine samples from the general population in Sanmen County are established, and successfully applied to two poisoning cases.

Changes in water manganese levels and longitudinal assessment of intellectual function in children exposed through drinking water.

PubMed

Dion, Laurie-Anne; Saint-Amour, Dave; Sauvé, Sébastien; Barbeau, Benoit; Mergler, Donna; Bouchard, Maryse F

2018-01-01

Manganese is commonly found in water but potential neurotoxic effects from exposure through drinking water are poorly understood. We previously reported a cross-sectional study showing that drinking water Mn concentration was associated with lower IQ in children aged 6 to 13 years. For this follow-up study, we aimed to re-assess the relation between exposure to Mn from drinking water and IQ at adolescence. In addition, we aimed to examine whether changes in drinking water Mn concentration was associated with changes in IQ scores. From the 380 children enrolled in the baseline study, 287 participated to this follow-up study conducted in average 4.4 years after. Mn concentration was measured in home tap water and children's hair. The relationships between these Mn exposure indicators and IQ scores (Weschsler Abbreviated Scale of Intelligence) at follow-up were assessed with linear regression analysis, adjusting for potential confounders. Intra-individual differences in IQ scores between the two examinations were compared for children whose Mn concentration in water remained stable between examinations, increased or decreased. The mean age at follow-up was 13.7 years (range, 10.5 to 18.0 years). Geometric mean of Mn concentration in water at follow-up was 14.5μg/L. Higher Mn concentration in water measured at follow-up was associated with lower Performance IQ in girls (β for a 10-fold increase=-2.8, 95% confidence intervals [CI] -4.8 to -0.8) and higher Performance IQ in boys (β=3.9, 95% CI 1.4 to 6.4). IQ scores were not significantly associated with Mn concentration in hair, although similar trends as for concentration in water were observed. For children whose Mn concentration in water increased between baseline and follow-up, Performance IQ scores decreased significantly (intra-individual difference, -2.4 points). Higher levels of Mn in drinking water were associated with lower Performance IQ in girls, whereas the opposite was observed in boys. These findings suggest long-term exposure to Mn through drinking water is associated differently with cognition in boys and girls. Copyright © 2017 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milatovic, Dejan, E-mail: dejan.milatovic@vanderbilt.edu; Gupta, Ramesh C.; Yu, Yingchun

Exposure to excessive manganese (Mn) levels leads to neurotoxicity, referred to as manganism, which resembles Parkinson's disease (PD). Manganism is caused by neuronal injury in both cortical and subcortical regions, particularly in the basal ganglia. The basis for the selective neurotoxicity of Mn is not yet fully understood. However, several studies suggest that oxidative damage and inflammatory processes play prominent roles in the degeneration of dopamine-containing neurons. In the present study, we assessed the effects of Mn on reactive oxygen species (ROS) formation, changes in high-energy phosphates and associated neuronal dysfunctions both in vitro and in vivo. Results from ourmore » in vitro study showed a significant (p < 0.01) increase in biomarkers of oxidative damage, F{sub 2}-isoprostanes (F{sub 2}-IsoPs), as well as the depletion of ATP in primary rat cortical neurons following exposure to Mn (500 {mu}M) for 2 h. These effects were protected when neurons were pretreated for 30 min with 100 of an antioxidant, the hydrophilic vitamin E analog, trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), or an anti-inflammatory agent, indomethacin. Results from our in vivo study confirmed a significant increase in F{sub 2}-IsoPs levels in conjunction with the progressive spine degeneration and dendritic damage of the striatal medium spiny neurons (MSNs) of mice exposed to Mn (100 mg/kg, s.c.) 24 h. Additionally, pretreatment with vitamin E (100 mg/kg, i.p.) or ibuprofen (140 {mu}g/ml in the drinking water for two weeks) attenuated the Mn-induced increase in cerebral F{sub 2}-IsoPs? and protected the MSNs from dendritic atrophy and dendritic spine loss. Our findings suggest that the mediation of oxidative stress/mitochondrial dysfunction and the control of alterations in biomarkers of oxidative injury, neuroinflammation and synaptodendritic degeneration may provide an effective, multi-pronged therapeutic strategy for protecting dysfunctional dopaminergic transmission and slowing of the progression of Mn-induced neurodegenerative processes. -- Research highlights: Black-Right-Pointing-Pointer Mn exposure leads to neurotoxicity in vitro and in vivo. Black-Right-Pointing-Pointer Antioxidants and anti-inflammatory agents attenuate Mn-induced oxidative injury. Black-Right-Pointing-Pointer These agents also protect the striatal neurons from dendritic atrophy and spine loss. Black-Right-Pointing-Pointer These prophylactic strategies may be effective against Mn neurotoxicity.« less

Interplay of Dirac electrons and magnetism in CaMnBi 2 and SrMnBi 2

DOE PAGES

Zhang, Anmin; Liu, Changle; Yi, Changjiang; ...

2016-12-16

Dirac materials exhibit intriguing low-energy carrier dynamics that offer a fertile ground for novel physics discovery. Something of particular interest is the interplay of Dirac carriers with other quantum phenomena such as magnetism. We report on a two-magnon Raman scattering study of AMnBi 2 (A=Ca, Sr), a prototypical magnetic Dirac system comprising alternating Dirac carrier and magnetic layers. We present the first accurate determination of the exchange energies in these compounds and, by comparison with the reference compound BaMn 2Bi 2, we show that the Dirac carrier layers in AMnBi 2 significantly enhance the exchange coupling between the magnetic layers,more » which in turn drives a charge-gap opening along the Dirac locus. These findings break new grounds in unveiling the fundamental physics of magnetic Dirac materials, which offer a novel platform for probing a distinct type of spin–Fermion interaction. Our results also hold great promise for applications in magnetic Dirac devices.« less

Understanding Lignin-Degrading Reactions of Ligninolytic Enzymes: Binding Affinity and Interactional Profile

PubMed Central

Chen, Ming; Zeng, Guangming; Tan, Zhongyang; Jiang, Min; Li, Hui; Liu, Lifeng; Zhu, Yi; Yu, Zhen; Wei, Zhen; Liu, Yuanyuan; Xie, Gengxin

2011-01-01

Previous works have demonstrated that ligninolytic enzymes mediated effective degradation of lignin wastes. The degrading ability greatly relied on the interactions of ligninolytic enzymes with lignin. Ligninolytic enzymes mainly contain laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP). In the present study, the binding modes of lignin to Lac, LiP and MnP were systematically determined, respectively. Robustness of these modes was further verified by molecular dynamics (MD) simulations. Residues GLU460, PRO346 and SER113 in Lac, residues ARG43, ALA180 and ASP183 in LiP and residues ARG42, HIS173 and ARG177 in MnP were most crucial in binding of lignin, respectively. Interactional analyses showed hydrophobic contacts were most abundant, playing an important role in the determination of substrate specificity. This information is an important contribution to the details of enzyme-catalyzed reactions in the process of lignin biodegradation, which can be used as references for designing enzyme mutants with a better lignin-degrading activity. PMID:21980516

[Determination of Al, Be, Cd, Co, Cr, Mn, Ni, Pb, Se and Tl in whole blood by atomic absorption spectrometry without preliminary sample digestion].

PubMed

Ivanenko, N B; Ivanenko, A A; Solov'ev, N D; Navolotskiĭ, D V; Pavlova, O V; Ganeev, A A

2014-01-01

Methods of whole blood trace element determination by Graphite furnace atomic absorption spectrometry (in the variant of Zeeman's modulation polarization spectrometry) have been proposed. They do not require preliminary sample digestion. Furnace programs, modifiers and blood dilution factors were optimized. Seronorm™ human whole blood reference materials were used for validation. Dynamic ranges (for undiluted blood samples) were: Al 8 ¸ 210 мg/L; Be 0.3 ¸ 50 мg/L; Cd 0.2 ¸ 75 мg/L; Сo 5 ¸ 350 мg/L; Cr 10 ¸ 100 мg/L; Mn 6 ¸ 250 мg/L; Ni 10 ¸ 350 мg/L; Pb 3 ¸ 240 мg/L; Se 10 ¸ 500 мg/L; Tl 2 ¸ 600 мg/L. Precision (RSD) for the middle of dynamic range ranged from 5% for Mn to 11 for Se.

Interplay of Dirac electrons and magnetism in CaMnBi2 and SrMnBi2

PubMed Central

Zhang, Anmin; Liu, Changle; Yi, Changjiang; Zhao, Guihua; Xia, Tian-long; Ji, Jianting; Shi, Youguo; Yu, Rong; Wang, Xiaoqun; Chen, Changfeng; Zhang, Qingming

2016-01-01

Dirac materials exhibit intriguing low-energy carrier dynamics that offer a fertile ground for novel physics discovery. Of particular interest is the interplay of Dirac carriers with other quantum phenomena such as magnetism. Here we report on a two-magnon Raman scattering study of AMnBi2 (A=Ca, Sr), a prototypical magnetic Dirac system comprising alternating Dirac carrier and magnetic layers. We present the first accurate determination of the exchange energies in these compounds and, by comparison with the reference compound BaMn2Bi2, we show that the Dirac carrier layers in AMnBi2 significantly enhance the exchange coupling between the magnetic layers, which in turn drives a charge-gap opening along the Dirac locus. Our findings break new grounds in unveiling the fundamental physics of magnetic Dirac materials, which offer a novel platform for probing a distinct type of spin–Fermion interaction. The results also hold great promise for applications in magnetic Dirac devices. PMID:27982036

Deregulation of Mitochondria-Shaping Proteins Opa-1 and Drp-1 in Manganese-Induced Apoptosis

PubMed Central

Alaimo, Agustina; Gorojod, Roxana M.; Beauquis, Juan; Muñoz, Manuel J.; Saravia, Flavia; Kotler, Mónica L.

2014-01-01

Mitochondria are dynamic organelles that undergo fusion and fission processes. These events are regulated by mitochondria-shaping proteins. Changes in the expression and/or localization of these proteins lead to a mitochondrial dynamics impairment and may promote apoptosis. Increasing evidence correlates the mitochondrial dynamics disruption with the occurrence of neurodegenerative diseases. Therefore, we focused on this topic in Manganese (Mn)-induced Parkinsonism, a disorder associated with Mn accumulation preferentially in the basal ganglia where mitochondria from astrocytes represent an early target. Using MitoTracker Red staining we observed increased mitochondrial network fission in Mn-exposed rat astrocytoma C6 cells. Moreover, Mn induced a marked decrease in fusion protein Opa-1 levels as well as a dramatic increase in the expression of fission protein Drp-1. Additionally, Mn provoked a significant release of high MW Opa-1 isoforms from the mitochondria to the cytosol as well as an increased Drp-1 translocation to the mitochondria. Both Mdivi-1, a pharmacological Drp-1 inhibitor, and rat Drp-1 siRNA reduced the number of apoptotic nuclei, preserved the mitochondrial network integrity and prevented cell death. CsA, an MPTP opening inhibitor, prevented mitochondrial Δψm disruption, Opa-1 processing and Drp-1 translocation to the mitochondria therefore protecting Mn-exposed cells from mitochondrial disruption and apoptosis. The histological analysis and Hoechst 33258 staining of brain sections of Mn-injected rats in the striatum showed a decrease in cellular mass paralleled with an increase in the occurrence of apoptotic nuclei. Opa-1 and Drp-1 expression levels were also changed by Mn-treatment. Our results demonstrate for the first time that abnormal mitochondrial dynamics is implicated in both in vitro and in vivo Mn toxicity. In addition we show that the imbalance in fusion/fission equilibrium might be involved in Mn-induced apoptosis. This knowledge may provide new therapeutic tools for the treatment of Manganism and other neurodegenerative diseases. PMID:24632637

Deregulation of mitochondria-shaping proteins Opa-1 and Drp-1 in manganese-induced apoptosis.

PubMed

Alaimo, Agustina; Gorojod, Roxana M; Beauquis, Juan; Muñoz, Manuel J; Saravia, Flavia; Kotler, Mónica L

2014-01-01

Mitochondria are dynamic organelles that undergo fusion and fission processes. These events are regulated by mitochondria-shaping proteins. Changes in the expression and/or localization of these proteins lead to a mitochondrial dynamics impairment and may promote apoptosis. Increasing evidence correlates the mitochondrial dynamics disruption with the occurrence of neurodegenerative diseases. Therefore, we focused on this topic in Manganese (Mn)-induced Parkinsonism, a disorder associated with Mn accumulation preferentially in the basal ganglia where mitochondria from astrocytes represent an early target. Using MitoTracker Red staining we observed increased mitochondrial network fission in Mn-exposed rat astrocytoma C6 cells. Moreover, Mn induced a marked decrease in fusion protein Opa-1 levels as well as a dramatic increase in the expression of fission protein Drp-1. Additionally, Mn provoked a significant release of high MW Opa-1 isoforms from the mitochondria to the cytosol as well as an increased Drp-1 translocation to the mitochondria. Both Mdivi-1, a pharmacological Drp-1 inhibitor, and rat Drp-1 siRNA reduced the number of apoptotic nuclei, preserved the mitochondrial network integrity and prevented cell death. CsA, an MPTP opening inhibitor, prevented mitochondrial Δψm disruption, Opa-1 processing and Drp-1 translocation to the mitochondria therefore protecting Mn-exposed cells from mitochondrial disruption and apoptosis. The histological analysis and Hoechst 33258 staining of brain sections of Mn-injected rats in the striatum showed a decrease in cellular mass paralleled with an increase in the occurrence of apoptotic nuclei. Opa-1 and Drp-1 expression levels were also changed by Mn-treatment. Our results demonstrate for the first time that abnormal mitochondrial dynamics is implicated in both in vitro and in vivo Mn toxicity. In addition we show that the imbalance in fusion/fission equilibrium might be involved in Mn-induced apoptosis. This knowledge may provide new therapeutic tools for the treatment of Manganism and other neurodegenerative diseases.

Does Science Presuppose Naturalism (or Anything at All)?

NASA Astrophysics Data System (ADS)

Fishman, Yonatan I.; Boudry, Maarten

2013-05-01

Several scientists, scientific institutions, and philosophers have argued that science is committed to Methodological Naturalism (MN), the view that science, by virtue of its methods, is limited to studying `natural' phenomena and cannot consider or evaluate hypotheses that refer to supernatural entities. While they may in fact exist, gods, ghosts, spirits, and extrasensory or psi phenomena are inherently outside the domain of scientific investigation. Recently, Mahner (Sci Educ 3:357-371, 2012) has taken this position one step further, proposing the more radical view that science presupposes an a priori commitment not just to MN, but also to ontological naturalism (ON), the metaphysical thesis that supernatural entities and phenomena do not exist. Here, we argue that science presupposes neither MN nor ON and that science can indeed investigate supernatural hypotheses via standard methodological approaches used to evaluate any `non-supernatural' claim. Science, at least ideally, is committed to the pursuit of truth about the nature of reality, whatever it may be, and hence cannot exclude the existence of the supernatural a priori, be it on methodological or metaphysical grounds, without artificially limiting its scope and power. Hypotheses referring to the supernatural or paranormal should be rejected not because they violate alleged a priori methodological or metaphysical presuppositions of the scientific enterprise, but rather because they fail to satisfy basic explanatory criteria, such as explanatory power and parsimony, which are routinely considered when evaluating claims in science and everyday life. Implications of our view for science education are discussed.

Community Exposure to Air Manganese and Motor and ...

EPA Pesticide Factsheets

Although manganese (Mn) is an essential nutrient, occupational studies have shown inhaling high levels of Mn can lead to adverse nervous system health effects. Few studies have examined the health effects of air-Mn exposure on adults in a community. We conducted a cross-sectional study in a control town (Mt. Vernon, Ohio) and 2 towns (Marietta and East Liverpool, Ohio) with elevated air-Mn due to industrial processes. Recruited participants were aged 30-75 years and resided 10 or more years within respective town. Data included neurological and neuropsychological test results. Air modeling was conducted for Marietta (range 0.03-1.61 µg/m3) and East Liverpool (0.01-6.32 µg/m3). Town differences for outcomes used ANOVA (results reported as [F-statistic; partial eta squared (p-value)]). For Marietta and East Liverpool, Spearman’s rho was used to calculate correlations between air-Mn and motor and cognitive outcomes (results reported as [rho(p-value)]). East Liverpool had poorer scores than Marietta and Mount Vernon for word reading [3.7;.03(0.27)]; motor speed dominant hand (DH)[11.5;.08 (<.001)], non-dominant hand (NDH)[7.1;.05(.001)], motor strength DH[10.5;.07(<.001)], NDH[6.3;.04(.002)]; and tactile function DH [7.1;.05(.001)]. Higher air-Mn was correlated to slower motor speed DH[ -.26(<.001)], NDH[ -.16 (.027)]; and worse tactile function scores NDH[ -.15(.04)]. For cognitive outcomes, higher air-Mn was correlated to lower scores on daily memory immediate

A Synthetic Calcite Standard for Determination of Relative Mn/Cr Sensitivity Factor

NASA Astrophysics Data System (ADS)

Fujiya, W.; Ichimura, K.; Takahata, N.; Sugiura, N.; Sano, Y.

2009-12-01

Primitive chondrites which suffered from aqueous alteration often contain carbonates such as calcites, dolomites and breunnerites. 53Mn-53Cr decay system (half-life: 3.7 Myr) is applicable to dating their precipitation and many authors have measured their Mn-Cr ages using the SIMS. However, the relative Mn/Cr sensitivity factor: RSF (measured Mn+/Cr+ ratio divided by the true ratio) is not well established due to the absence of suitable standards, therefore the ages have systematic uncertainties. We prepared a synthetic Mn and Cr bearing calcite to evaluate the Mn/Cr RSF. Here we report the technical details of preparation for the standard and its Mn/Cr RSF. We also measured the Mn/Cr RSF of San Carlos olivine which is often assumed to be the same as that of a carbonate, and compared it with that of our synthetic calcite. The Cr-bearing calcite was produced in a N2 filled closed system by the reaction Ca2+ + CO32- = CaCO3 in an aqueous solution. The reaction proceeded by continuous addition of ammonium carbonate vapor to the solution. The crystal size of the calcite was ~300 μm. A small amount of hydrazine was added to the solution in order to keep chromous ion from oxidation. Mn and Cr concentrations in the calcite grains were determined by the SEM-EDS. A weak, defocused beam was used due to prevent electron beam damage. In a spherical grain, radial zoning of Mn and Cr concentrations occur and they decrease towards the periphery. At the center of the grains, Mn and Cr concentrations are ~0.5 atomic % and the values of the Mn/Cr ratios are relatively constant. The Mn/Cr RSF was determined with the CAMECA NanoSIMS 50 at Ocean Research Institute of Univ. of Tokyo. A primary O- beam of ~1 nA and 5 μm diameter was used. 43Ca+, 52Cr+, 53Cr+ and 55Mn+ ions were analyzed in a combined peak-jumping/multi-detection mode. The total measurement time was typically ~20 minutes. The measurements were started after presputtering of 15 minutes. The mass resolution power was ~3500, sufficient to resolve all relevant isobaric interferences. Several points near the center of calcite grains with constant Mn and Cr concentrations were measured. As for San Carlos olivine, a primary beam was rastered over 20 x 20 μm2 areas. Signals of all ions decreased with time during the measurements. The 55Mn/52Cr RSF also decreased with time. Initially it was ~0.7-0.8, and approached to a nearly constant value of ~0.5-0.6 after ~20 minutes. 53Cr+/52Cr+ isotopic ratio was 0.1105 ± 0.0002 (1σ), not dependent on time and space. This value corresponds to ~-26 permil fractionation from the reference value. On the other hand, the RSF of San Carlos olivine was found to be ~0.9, consistent with previous studies. The RSF of our calcite is significantly lower than the values used in previous studies and the RSF of San Carlos olivine measured in this study. This implies that Mn-Cr ages for carbonates obtained in previous studies may have systematic biases (~3 Myr).

Determination of manganese- and manganese-containing fungicides with lucigenin-Tween-20-enhanced chemiluminescence detection.

PubMed

Yaqoob, Mohammad; Asghar, Mohammad; Nabi, Abdul

2015-11-01

A flow-injection (FI) method is reported for the determination of Mn(II), maneb and mancozeb fungicides based on the catalytic effect of Mn(II) on the oxidation of lucigenin and dissolved oxygen in a basic solution. The Tween-20 surfactant has been reported for first time to enhance lucigenin chemiluminescence (CL) intensity in the presence of Mn(II) (53%) and maneb and mancozeb (89%). The calibration graphs were linear in the concentration range of 0.001-1.5 mg L(-1) (R(2) = 0.9982 (n = 11) with a limit of detection (S/N = 3) of 0.1 µg L(-1) for Mn(II) and 0.01-3.0 mg L(-1) [R(2) = 0.9989 and R(2) = 0.9992 (n = 6)] with a limit of detection (S/N =3) of 1.0 µg L(-1) for maneb and mancozeb respectively. Injection throughputs of 90 and 120 h(-1) for Mn(II) and maneb and mancozeb respectively, and relative standard deviations of 1.0-3.4% were obtained in the concentration range studied. The experimental variables, e.g., reagents concentrations, flow rates, sample volume, and photomultiplier tube voltage, were optimized and potential interferences were investigated. The analysis of Mn(II) in river water reference materials (SLRS-4 and SLRS-5) showed good agreement with the certified values incorporating an on-line 8-hydroxyquinoline chelating column in the manifold for removing interfering metal ions. Recoveries for maneb and mancozeb were in the range of 92 ± 5 to 104 ± 3% and 91 ± 2 to 100 ± 4% (n = 3) respectively. The effect of 30 other pesticides (fungicides, herbicides and insecticides) was also examined in the lucigenin-Tween-20 CL system. Copyright © 2015 John Wiley & Sons, Ltd.

Corrosion Behavior of Low-C Medium-Mn Steel in Simulated Marine Immersion and Splash Zone Environment

NASA Astrophysics Data System (ADS)

Zhang, Dazheng; Gao, Xiuhua; Su, Guanqiao; Du, Linxiu; Liu, Zhenguang; Hu, Jun

2017-05-01

The corrosion behavior of low-C medium-Mn steel in simulated marine immersion and splash zone environment was studied by static immersion corrosion experiment and wet-dry cyclic corrosion experiment, respectively. Corrosion rate, corrosion products, surface morphology, cross-sectional morphology, elemental distribution, potentiodynamic polarization curves and electrochemical impedance spectra were used to elucidate the corrosion behavior of low-C medium-Mn steel. The results show that corrosion rate in immersion zone is much less than that in splash zone owing to its relatively mild environment. Manganese compounds are detected in the corrosion products and only appeared in splash zone environment, which can deteriorate the protective effect of rust layer. With the extension of exposure time, corrosion products are gradually transformed into dense and thick corrosion rust from the loose and porous one in these two environments. But in splash zone environment, alloying elements of Mn appear significant enrichment in the rust layer, which decrease the corrosion resistance of the steel.

Iron-[S,S']-EDDS (FeEDDS) Chelate as an Iron Source for Horticultural Crop Production: Marigold Growth and Nutrition, Spectral Properties, and Photodegradation

USDA-ARS?s Scientific Manuscript database

Aminopolycarboxylic acid (APCA) complexones, commonly referred to as ligands or chelating agents, like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to p...

Project Management Done Here: Lois Langer--Thompson Hennepin County Library, MN

ERIC Educational Resources Information Center

Library Journal, 2004

2004-01-01

How do you simultaneously renovate a grocery store into a state-of-the-art resource library, supervise the daily operations of five libraries, lead a team in reimagining reference service, and plan your wedding? Ask Lois Langer, coordinating librarian of Hennepin County Library. Her answer: "Project management--you can do anything,…

Magneto-structural correlation in a series of bimetallic alternating chain complexes of [CrIIIL(CN)4]n[MnIII(salpn)]n.nsolvents (L=2,2'-bipy or 9,10-phen, salpn=substituted salicyldehyde, solvents=water and methanol).

PubMed

Pan, Feng; Wang, Zhe-Ming; Gao, Song

2007-11-26

Five chain compounds based on the building block of [Cr(L)(CN)4]- (L=2,2'-bipy, 1-4; L=9,10-phen, 5) and [Mn(salpn)]+ (salpn=substituted salicyldehyde-type Schiff base in Scheme 1) have been prepared and characterized structurally and magnetically. The four compounds (1-4) consisting of [Cr(bipy)(CN)4]- units possess straight bimetallic chains as the [Cr(bpy)(CN)4]- unit links the two neighbor [Mn(salpn)]+ units with the two trans-cyanide ligands, while in 5 the chain is zigzag because the [Cr(phen)(CN)4]- unit connects the [Mn(salpn)]+ units with its two cis-cyanide ligands. The bond angles of Mn-N-C-Cr are adjusted by different coligands of salpn and bipy/phen. The chains are stacking via mainly the aromatic pi-pi-type interactions. All compounds show 3D antiferromagnetic ordering with Néel temperatures ranging from 3.7 to 8.1 K, and they are metamagnets displaying antiferromagnetic to ferrimagnetic transition at critical fields of 4.0-13.1 kOe at 1.9 K. This is due to weak interchain antiferromagnetic interactions between the ferrimagnetic bimetallic chains in the materials. The intrachain couplings (J, in cm(-1)) in the materials, between cyanide-bridged CrIII and MnIII ions, from -1.84 to -5.35 cm(-1), follow a linear relationship (J=-33+0.18alpha) to the Mn-N-C angles (alpha, in deg). In addition, the weak interchain antiferromagnetic interactions and critical fields for antiferromagnetic-ferrimagnetic transition are closely related to some of their structural factors, which were studied very superficially only referring to the separations of nearest chains in each material.

Magnetostratigraphy of the Vallesian (late Miocene) in the Vallès-Penedès Basin (northeast Spain)

NASA Astrophysics Data System (ADS)

Garcés, M.; Agustí, J.; Cabrera, L.; Parés, J. M.

1996-08-01

The magnetostratigraphic analysis of the late Miocene continental deposits from the Vallès-Penedès Basin, combined with its well-documented fossil mammal record, has provided a well-resolved chronology for the upper basin infill. The study is based on the biostratigraphic and magnetostratigraphic cross-correlation of 12 sections throughout the alluvial sequences in the western Vallès area. The biostratigraphic framework consists of 21 mammal localities corresponding to the Mammal Neogene MN9 and MN10 units. The composite magnetic polarity sequence is based on 400 paleomagnetic sites. Correlation with the Geomagnetic Polarity Time Scale (GPTS) has led to an absolute dating of the faunal events and a precise chronostratigraphy of the Vallesian mammal stage in its type area. The Hipparion First Appearance Datum (FAD), at the MN8/MN9 boundary, is dated at 11.1 Ma in the Vallès-Penedès Basin. This age, compared to other radiometrically dated localities in Europe, North Africa and Turkey, is consistent with an isochronous dispersal of this equid through the Mediterranean region. A possible isochrony at a larger geographical scale (Old World, Mesogea) must await more reliable ages of the Hipparion FAD in Asia and Africa. The Cricetulodon FAD ( MN9a/MN9b boundary) is dated to 10.4 Ma, in chron C5n. The Progonomys FAD ( MN9/MN10 boundary), corresponding to the intra-Vallesian faunal crisis, is dated at 9.7 Ma (C4Ar.3r). The Vallesian spans 2.4 Myr, from 11.1 Ma (C5r.1n) to 8.7 Ma (C4An) and correlates to the early Tortonian.

Interface adjustment and exchange coupling in the IrMn/NiFe system

NASA Astrophysics Data System (ADS)

Spizzo, F.; Tamisari, M.; Chinni, F.; Bonfiglioli, E.; Del Bianco, L.

2017-01-01

The exchange bias effect was investigated, in the 5-300 K temperature range, in samples of IrMn [100 Å]/NiFe [50 Å] (set A) and in samples with inverted layer-stacking sequence (set B), produced at room temperature by DC magnetron sputtering in a static magnetic field of 400 Oe. The samples of each set differ for the nominal thickness (tCu) of a Cu spacer, grown at the interface between the antiferromagnetic and ferromagnetic layers, which was varied between 0 and 2 Å. It has been found out that the Cu insertion reduces the values of the exchange field and of the coercivity and can also affect their thermal evolution, depending on the stack configuration. Indeed, the latter also determines a peculiar variation of the exchange bias properties with time, shown and discussed with reference to the samples without Cu of the two sets. The results have been explained considering that, in this system, the exchange coupling mechanism is ruled by the glassy magnetic behavior of the IrMn spins located at the interface with the NiFe layer. Varying the stack configuration and tCu results in a modulation of the structural and magnetic features of the interface, which ultimately affects the spins dynamics of the glassy IrMn interfacial component.

Analysis of urinary metanephrines by reversed-phase high-performance liquid chromatography and electrochemical detection.

PubMed

Bertani-Dziedzic, L M; Krstulovic, A M; Dziedzic, S W; Gitlow, S E; Cerqueira, S

1981-02-19

A sensitive and specific direct analysis of urinary normetanephrine (NMN) and metanephrine (MN) was achieved utilizing reversed-phase high performance liquid chromatography and electrochemical detection. Individual specimens from "control" subjects and those with pheochromocytoma were hydrolyzed and the metanephrines separated from other urinary constituents by elution with ammonia from a Dowex CG-50 resin. Chromatographic peaks were identified by retention behavior, co-chromatography with reference compounds, ratio of responses at various oxidation potentials and stopped-flow UV spectra of the collected fractions. The NMN and MN content for the control subjects was between 0.086 and 0.21 (mean - 0.14) microgram/mg creatinine and 0.012 and 0.092 (mean = 0.039) microgram/mg creatinine, respectively. The values for subjects with pheochromocytoma varied from 1.5 to 27.5 (mean = 9.9) microgram/mg creatinine for NMN and 0.10 to 1.60 (mean = 0.86) microgram/mg creatine for MN. The patient with ganglioneuroma had an NMN of 4.1 and an MN of 0.80 microgram/mg creatinine. While this method permits discrimination between those patients with pheochromocytoma and the overwhelming majority of hypertensive patients, it may ultimately be further extended to separate normal subjects from those with more subtle derangements in catecholamine metabolism.

Medullary neurons in the core white matter of the olfactory bulb: a new cell type.

PubMed

Paredes, Raúl G; Larriva-Sahd, Jorge

2010-02-01

The structure of a new cell type, termed the medullary neuron (MN) because of its intimate association with the rostral migratory stream (RMS) in the bulbar core, is described in the adult rat olfactory bulb. The MN is a triangular or polygonal interneuron whose soma lies between the cellular clusters of the RMS or, less frequently, among the neuron progenitors therein. MNs are easily distinguished from adjacent cells by their large size and differentiated structure. Two MN subtypes have been categorized by the Golgi technique: spiny pyramidal neurons and aspiny neurons. Both MN subtypes bear a large dendritic field impinged upon by axons in the core bulbar white matter. A set of collaterals from the adjacent axons appears to terminate on the MN dendrites. The MN axon passes in close apposition to adjacent neuron progenitors in the RMS. MNs are immunoreactive with antisera raised against gamma-aminobutyric acid and glutamate decarboxylase 65/67. Electron-microscopic observations confirm that MNs correspond to fully differentiated, mature neurons. MNs seem to be highly conserved among macrosmatic species as they occur in Nissl-stained brain sections from mouse, guinea pig, and hedgehog. Although the functional role of MNs remains to be determined, we suggest that MNs represent a cellular interface between endogenous olfactory activity and the differentiation of new neurons generated during adulthood.

Magnetization reversal in ferromagnetic wires patterned with antiferromagnetic gratings

NASA Astrophysics Data System (ADS)

Sani, S. R.; Liu, F.; Ross, C. A.

2017-04-01

The magnetic reversal behavior is examined for exchange-biased ferromagnetic/antiferromagnetic nanostructures consisting of an array of 10 nm thick Ni80Fe20 stripes with width 200 nm and periodicity 400 nm, underneath an orthogonal array of 10 nm thick IrMn stripes with width ranging from 200 nm to 500 nm and periodicity from 400 nm to 1 μm. The Ni80Fe20 stripes show a hysteresis loop with one step when the IrMn width and spacing are small. However, upon increasing the IrMn width and spacing, the hysteresis loops showed two steps as the pinned and unpinned sections of the Ni80Fe20 stripes switch at different fields. Micromagnetic modeling reveals the influence of geometry on the reversal behavior.

TEM Study of Manganese Biosorption by Cyanobacterium Synechocystis 6803

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dohnalkova, Alice; Bilskis, Christina L.; Kennedy, David W.

2006-09-01

The capture of solar energy and its conversion into chemical energy in photosynthetic organisms involves a series of charge reactions across photosynthetic membranes. Oxygen is generated by a proton-electron coupling in photosystem II (PSII) during a water oxidation process where hydrogen is extracted from water terminally bound to a Mn4Ca1Clx inorganic cluster [1]. Manganese is, therefore, an essential catalytic element for photosynthetic growth in cyanobacteria and plants. Since bioavailability of this micronutrient largely depends on the Mn concentration in natural environments, cells have to manage its uptake in order to endure Mn fluctuations. Previous studies have shown that metal biosorptionmore » in cyanobacteria can occur by passive adsorption to their outer membrane (pool A), and by metabolically mediated internal uptake [2]. The fresh water cyanobacterium Synechocystis 6803 has been widely used as a model organism for studying photosynthetic processes. This Gram-negative organism has an intricate architecture of internal thylakoid membranes where photosynthetic electron transfer takes place. Here we report on the spatial distribution of Mn biosorbed by cells in both external pool A and intracellular pool B, as observed and analyzed by methods of TEM. The Synechocystis 6803 cells were cultured in BG11 medium at 30 C with continuous irradiance and constant air bubbling. To determine the influence of solid or liquid Mn substrate and its oxidation state on the cell biosorption ability, cells were exposed to two Mn substrates: 1mM solution of MnCl2, and 0.5mM suspension of nanocrystalline MnO2. Cells were incubated with the respective Mn solutions for 48 hours, harvested, and processed using a modified protocol for plastic embedding of bacterial samples containing minerals that was developed in our laboratory [3]. In order to preserve the fragile redox conditions within the cells, all the common heavy metal-based fixatives and stains were omitted, resulting in cells with very low contrast produced principally by electron-dense manganese precipitates. Thin sections were imaged and analyzed using JEOL 2010 HRTEM coupled with EDS (Oxford) and EELS (Gatan) systems. Manganese uptake was measured using a colorimetric method. Cells incubated with Mn solutions were able to take up about 150uM of Mn(II) or Mn(IV) in 48 hours. The predominant accumulation of Mn was associated with the outer membrane for both Mn substrates. Massive deposits seemed to be related in a large extent to the external polymeric substances (EPS) as shown in Fig. 1A-C. Elemental analyses of these precipitates revealed a signal consistent with manganese phosphate. The potential of EPS such as polysaccharides for biosorption or reduction of metals has been described [4], however, the fact that Mn bound to the EPS withstood multiple washes during TEM sample processing is remarkable. From our work with Gram-negative soil bacteria, we hypothesized that the periplasm, an area between the outer and plasma membrane, might be the storage space for internal Mn in pool B. This phenomenon was not observed at any time point for either culture exposed to the Mn. Instead, thin layers of Mn deposits were often found lining the outer and plasma membrane (F). In the MnCl2 solution only, we also observed fine deposits of Mn precipitates along the thylakoid membranes deep inside the cells (Fig. E). Localization of Mn precipitation sites in Synechocystis has important implications for better understanding of the Mn transport and storage processes within cyanobacterial cells, as well as of metal precipitation, solubilization and cycling in the environment.« less

Anaerobic nitrification-denitrification mediated by Mn-oxides in meso-tidal sediments: Implications for N2 and N2O production

NASA Astrophysics Data System (ADS)

Fernandes, Sheryl Oliveira; Javanaud, Cedric; Aigle, Axel; Michotey, Valérie D.; Guasco, Sophie; Deborde, Jonathan; Deflandre, Bruno; Anschutz, Pierre; Bonin, Patricia C.

2015-04-01

Field measurements in the Arcachon Bay (southwest France) indicated anaerobic production of NOx via nitrification, which was coupled to the reduction of Mn-oxides. To prove the occurrence of this process, laboratory microcosm experiments were set up. A 15N tracer-based approach was used to track if NOx produced through Mn-oxide-mediated anaerobic nitrification would be reduced to N2 via denitrification or anammox. We also hypothesized the generation of the potent greenhouse gas nitrous oxide (N2O) during nitrification-denitrification in the presence of Mn-oxides. The microcosms were prepared using sediment sectioned at varying depths (0-2.5, 2.5-4.5, 4.5-8.5, 8.5-12 and 12-17 cm) during two sampling campaigns in October (fall) and January (winter). Labeling with 15NO3- revealed low N2 production originating from NO3- in the water column (Pw), which did not increase significantly on amendment with Mn-oxides during both sampling periods. However, for both seasons, a significant increase of N2 produced via nitrification (Pn) was observed upon addition of Mn-oxides reaching 76-fold enhancement at ≤ 2.5 cm. To support these results, sediment slurries of October were subjected to amendment of 15NH4+, 14NO3- with or without addition of Mn-oxides. A substantial production of P15 (N2 production from 15NH4+) within 0-17 cm provided further evidence on nitrification-denitrification mediated by Mn-oxides probably with minimal intervention of anammox. In organically rich sediments, anaerobic nitrification-denitrification mediated by Mn-oxides could play an important role in lowering re-mineralized NH4+ levels in the benthic system. As hypothesized, significant production of N2O through the pathway was observed revealing newer mechanisms leading to the generation of the radiative gas.

Trace metal-rich Quaternary hydrothermal manganese oxide and barite deposit, Milos Island, Greece

USGS Publications Warehouse

Hein, J.R.; Stamatakis, G.; Dowling, J.S.

2000-01-01

The Cape Vani Mn oxide and barite deposit on Milos Island offers an excellent opportunity to study the three-dimensional characteristics of a shallow-water hydrothermal system. Milos Island is part of the active Aegean volcanic arc. A 1 km long basin located between two dacitic domes in northwest Milos is filled with a 35-50 m thick section of Quaternary volcaniclastic and pyroclastic rocks capped by reef limestone that were hydrothermally mineralized by Mn oxides and barite. Manganese occurs as thin layers, as cement of sandstone and as metasomatic replacement of the limestone, including abundant fossil shells. Manganese minerals include chiefly δ-MnO2, pyrolusite and ramsdellite. The MnO contents for single beds range up to 60%. The Mn oxide deposits are rich in Pb (to 3.4%), BaO (to 3.1%), Zn (to 0.8%), As (to 0.3%), Sb (to 0.2%) and Ag (to 10 ppm). Strontium isotopic compositions of the Mn oxide deposits and sulphur isotopic compositions of the associated barite show that the mineralizing fluids were predominantly sea water. The Mn oxide deposit formed in close geographical proximity to sulphide-sulphate-Au-Ag deposits and the two deposit types probably formed from the same hydrothermal system. Precipitation of Mn oxide took place at shallow burial depths and was promoted by the mixing of modified sea water (hydrothermal fluid) from which the sulphides precipitated at depth and sea water that penetrated along faults and fractures in the Cape Vani volcaniclastic and tuff deposits. The hydrothermal fluid was formed from predominantly sea water that was enriched in metals leached from the basement and overlying volcanogenic rocks. The hydrothermal fluids were driven by convection sustained by heat from cooling magma chambers. Barite was deposited throughout the time of Mn oxide mineralization, which occurred in at least two episodes. Manganese mineralization occurred by both focused and diffuse flow, the fluids mineralizing the beds of greatest porosity and filling dilatational fractures along with barite.

Bioaccumulation and locomotor effects of manganese phosphate/sulfate mixture in Sprague-Dawley rats following subchronic (90 days) inhalation exposure.

PubMed

Salehi, Fariba; Krewski, Daniel; Mergler, Donna; Normandin, Louise; Kennedy, Greg; Philippe, Suzanne; Zayed, Joseph

2003-09-15

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic manganese (Mn) compound added to unleaded gasoline in Canada. The primary combustion products of MMT are Mn phosphate, Mn sulfate, and a Mn phosphate/Mn sulfate mixture. Concerns have been raised that the combustion products of MMT containing Mn could be neurotoxic, even at low levels of exposure. The objective of this study is to investigate exposure-response relationships for bioaccumulation and locomotor effects following subchronic inhalation exposure to a mixture of manganese phosphates/sulfate mixture. A control group and three groups of 30 male Sprague-Dawley rats were exposed in inhalation chambers for a period of 13 weeks, 5 days per week, 6 h a day. Exposure concentrations were 3000, 300, and 30 microg/m(3). At the end of the exposure period, locomotor activity and resting time tests were conducted for 36 h using a computerized autotrack system. Rats were then euthanized by exsanguination and Mn concentrations in different tissues (liver, lung, testis, and kidney) and blood and brain (caudate putamen, globus pallidus, olfactory bulb, frontal cortex, and cerebellum) were determined by neutron activation analysis. Increased manganese concentrations were observed in blood, kidney, lung, testis, and in all brain sections in the highest exposure group. Mn in the lung and in the olfactory bulb were dose dependent. Our data indicate that the olfactory bulb accumulated more Mn than other brain regions following inhalation exposure. Locomotor activity was increased at 3000 microg/m(3), but no difference was observed in resting time among the exposed groups. At the end of the experiment, rats exposed to 300 and 3000 microg/m(3) exhibited significantly decreased body weight in comparison with the control group. Biochemical profiles also revealed some significant differences in certain parameters, specifically alkaline phospatase, urea, and chlorate.

Periplasmic Manganese in a Subsurface Bacterium During Anaerobic Growth on Birnessite

NASA Astrophysics Data System (ADS)

Langley, S.; Glasauer, S.; Beveridge, T.

2002-12-01

In subsurface environments, where oxygen is not metabolically available for energy production, bacteria use alternate terminal electron acceptors (TEAs) to respire and grow. Anaerobic TEAs include, but are not limited to, Fe3+ and Mn4+. These metals can be present as mineral phases (e.g., ferrihydrite and hematite in the case of iron; birnessite and pyrolusite in the case of manganese). Bacteria bind strongly to minerals and reduce the metal by a process called dissimilatory metal reduction (DMR). Shewanella putrefaciens strain CN32 is a Gram-negative bacterium capable of DMR. In previous reports, when this organism was grown on birnessite, we observed cytoplasmic granules of a Mn-rich mineral phase, and an unusual deposition of electron-dense material within the periplasm (that region of the cell located between the inner and outer membranes). In an attempt to characterize the periplasmic precipitates, CN32 was inoculated into an anaerobic defined medium (DM), supplemented with 20 mM Mn (birnessite) and incubated in an anaerobic chamber. Reduced and total Mn concentrations were monitored using atomic absorption spectrophotometry, and cell numbers determined by viable counts on trypticase soy agar. TEM, combined with energy dispersive X-ray spectroscopy (EDS), was used to localize and confirm the presence of any Mn-rich depositions. Soluble Mn concentration increased steadily after inoculation, indicating active metabolism and metal reduction by the cells. Viable counts indicated that the cells reached their maximum number on day 9. Stained thin sections from 4-day-old samples examined with TEM showed cells in close association with the mineral. Secondary mineral products derived from birnessite reduction were evident (e.g., manganese phosphate). TEM-EDS also revealed the presence of ~30 nm-thick deposits of electron-dense material in the periplasm of some cells. However, examination of similar sections which had not been previously stained with osmium tetroxide (an oxidizing EM stain), failed to reveal similar periplasmic depositions. We therefore speculate that soluble manganese accumulated within the periplasm of the cells. This pool of soluble manganese was then precipitated upon addition of the oxidizing osmium stain, and appeared as the electron-dense precipitates in stained sections. We believe this is the first report of a pool of soluble manganese accumulating within the periplasm of cells during DMR. At this point, we do not know whether the accumulation is related to the anaerobic metabolism of the cells (i.e., biologically induced), or is simply a passive by-product of their growth on manganese minerals. Further studies are needed to fully investigate this point.

On the “alpha-phase” of Ca{sub 2−x}Sr{sub x}MnO{sub 4} and extending the chemistry of Sr{sub 7−y}Ca{sub y}Mn{sub 4}O{sub 15} to y>1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craddock, Sarah; Senn, Mark S.

There has been renewed interest in the Ruddlesden-Popper phase (n=2) of composition Ca{sub n+1}Mn{sub n}O{sub 3} {sub n+1} in the light of recent research that has highlighted the nature of the improper ferroelectric ground state, which arises due to the couplings between specific combinations of MnO{sub 6} octahedral rotations and tilts. A fruitful route to control these octahedral degrees of freedom, and hence such desired physical properties, is through chemical substitution on the A–site cation i.e. Ca{sub 2−x}Sr{sub x}MnO{sub 4} for n =1, and in light of this, we have reinvestigated the chemistry of this solid solution. Here we focusmore » on a common impurity phase observed during this synthesis which has been termed the “alpha-phase” in the literature. We show that this impurity phase is actually comprised mainly of a structure related to Sr{sub 7}Mn{sub 4}O{sub 15} but is found here with significantly higher Ca substitution than previously believed possible. Sr{sub 7}Mn{sub 4}O{sub 15} is an interesting structural type in its own right, but has been mainly overlooked to date, exhibiting interesting physics related to low dimensional magnetic ordering and dimer interactions, and we show here that the structural type is a likely candidate for exhibiting a multiferroic ground state. The prospect of being able to tune the lattice and the exchange interactions through further chemical substitution is likely to lead to a renewed interest in this material. - Graphical abstract: Extending the chemistry of Sr{sub 7−y}Ca{sub y}Mn{sub 4}O{sub 15} beyond y>1, revealing highly anisotropic cation ordering and tunable magnetic properties. - Highlights: • Chemistry of the unique structural type Sr{sub 7}Mn{sub 4}O{sub 15} is extended to high Ca concentrations. • Cation occupancy model is determined, showing highly anisotropic solubility of Ca on the 7 unique Sr crystallographic sites. • Anomalies in the magnetic susceptibility data are discussed with reference to symmetry arguments pointing towards a possible novel multiferroic mechanism in this material.« less

Reference Values of 14 Serum Trace Elements for Pregnant Chinese Women: A Cross-Sectional Study in the China Nutrition and Health Survey 2010-2012.

PubMed

Liu, Xiaobing; Zhang, Yu; Piao, Jianhua; Mao, Deqian; Li, Yajie; Li, Weidong; Yang, Lichen; Yang, Xiaoguang

2017-03-21

The development of reference values of trace elements is recognized as a fundamental prerequisite for the assessment of trace element nutritional status and health risks. In this study, a total of 1400 pregnant women aged 27.0 ± 4.5 years were randomly selected from the China Nutrition and Health Survey 2010-2012 (CNHS 2010-2012). The concentrations of 14 serum trace elements were determined by high-resolution inductively coupled plasma mass spectrometry. Reference values were calculated covering the central 95% reference intervals (P2.5-P97.5) after excluding outliers by Dixon's test. The overall reference values of serum trace elements were 131.5 (55.8-265.0 μg/dL for iron (Fe), 195.5 (107.0-362.4) μg/dL for copper (Cu), 74.0 (51.8-111.3) μg/dL for zinc (Zn), 22.3 (14.0-62.0) μg/dL for rubidium (Rb), 72.2 (39.9-111.6) μg/L for selenium (Se), 45.9 (23.8-104.3) μg/L for strontium (Sr), 1.8 (1.2-3.6) μg/L for molybdenum (Mo), 2.4 (1.2-8.4) μg/L for manganese (Mn), 1.9 (0.6-9.0) ng/L for lead (Pb), 1.1 (0.3-5.6) ng/L for arsenic (As), 835.6 (219.8-4287.7) ng/L for chromium (Cr), 337.9 (57.0-1130.0) ng/L for cobalt (Co), 193.2 (23.6-2323.1) ng/L for vanadium (V), and 133.7 (72.1-595.1) ng/L for cadmium (Cd). Furthermore, some significant differences in serum trace element reference values were observed between different groupings of age intervals, residences, anthropometric status, and duration of pregnancy. We found that serum Fe, Zn, and Se concentrations significantly decreased, whereas serum Cu, Sr, and Co concentrations elevated progressively compared with reference values of 14 serum trace elements in pregnant Chinese women. The reference values of serum trace elements established could play a key role in the following nutritional status and health risk assessment.

Manganese minerals and associated fine particulates in the streambed of Pinal Creek, Arizona, U.S.A.: a mining-related acid drainage problem

USGS Publications Warehouse

Lind, Carol J.; Hem, J.D.

1993-01-01

The Pinal creek drainage basin in Arizona is a good example of the principal non-coal source of mining-related acid drainage in the U.S.A., namely copper mining. Infiltration of drainage waters from mining and ore refining has created an acid groundwater plume that has reacted with calcite during passage through the alluvium, thereby becoming less acid. Where O2 is present and the water is partially neutralized, iron oxides have precipitated and, farther downstream where the pH of the stream water is near neutral, high-Mn crusts have developed. Trace metal composition of several phases in the Pinal Creek drainage basin illustrates the changes caused by mining activities and the significant control Mn-crusts and iron oxide deposits exert on the distribution and concentration of trace metals. The phases and locales considered are the dissolved phase of Webster Lake, a former acid waste disposal pond; selected sections of cores drilled in the alluvium within the intermittent reach of Pinal Creek; and the dissolved phase, suspended sediments, and streambed deposits at specified locales along the perennial reach of Pinal creek. In the perennial reach of Pinal Creek, manganese oxides precipitate from the streamflow as non-cemented particulates and coatings of streambed material and as cemented black crusts. Chemical and X-ray diffraction analyses indicate that the non-cemented manganese oxides precipitate in the reaction sequence observed in previous laboratory experiments using simpler solution composition, Mn3O4 to MnOOH to an oxide of higher oxidation number usually <4.0, i.e. Na-birnessite, and that the black cemented crusts contain (Ca,Mn,Mg)CO3 and a 7-A?? phyllomanganate mixture of rancieite ((Ca,Mn)Mn4O9 ?? (3H2O)) and takanelite ((Mn,Ca)Mn4O9 ?? (3H2O)). In the laboratory, aerating and increasing the pH of Pinal Creek water to 9.00 precipitated (Ca,Mn,Mg)CO3 from an anoxic groundwater that contained CO2 HCO3, and precipitated Mn3O4 and subsequently MnOOH from an oxic surface water from which most of the dissolved CO2 had been removed. It is suggested that the black cemented crusts form by precipitation of Fe on the Mn-enriched carbonates, creating a site for the MnFe oxidation cycle and thus encouraging the conversion of the carbonates to 7-A?? physllomanganates. The non-magnetic <63-??m size-fractions of the black cemented crusts consisted mostly of the manganese-calcium oxides but also contained about 20% (Ca,Mn,Mg)CO3, 5% Fe (calculated as FeOOH), 2-4% exchangeable cations, and trace amounts of several silicates. ?? 1992.

Palaeoredox indicators from the organic-rich Messinian early post-evaporitic deposits of the Apennines (Central Italy)

NASA Astrophysics Data System (ADS)

Sampalmieri, G.; Iadanza, A.; Cipollari, P.; Cosentino, D.; Lo Mastro, S.

2009-04-01

Bottom redox conditions in marine and lacustrine ancient basins are often inferred by the occurrence of peculiar sedimentological structures and microfaunal assemblages. The co-occurrence, in such environments, of authigenic uranium, framboidal pyrite, barite and Fe-Mn nodules and encrustations, provides a good constraint for palaeo reconstructions. Authigenic uranium is a common constituent of hydrocarbon source rocks: it forms at the sediment-water interface under oxygen-deficient conditions and accumulates together with organic matter (OM). Its precipitation is triggered by the reduction of the soluble U6+ion in seawater to insoluble U4+. With respect to black shales, uranium content has even been used to estimate the TOC. Also authigenic pyrite forms under anoxic conditions and replaces organic matter: 1) the increase in pyrite content and in organic matter are directly correlated; 2) the size distribution of framboidal pyrite (consistent with sulphate-reducing bacterial activity) is considered a measure of redox conditions within the sediment. Barite is an authigenic mineral related to Corg content, since its organic precipitation is triggered by sulphate-reduction processes occurring in decaying OM-bearing microenvironments. Finally, also Fe-Mn oxyhydroxide are typical indicators of redox conditions. About 6 My ago the Mediterranean Sea underwent a giant event of concentration referred to as Messinian Salinity Crisis, which can be roughly subdivided into an evaporitic and a post evaporitic phase. The post evaporitic phase (p-ev; 5.61-5.33 Ma) developed in a context of humid conditions and can be further distinguished into two steps: p-ev1 (early post evaporitic phase) and p-ev2 (late post evaporitic phase). Previous works focused on pev2, which is interpreted to represent the establishment of brackish water conditions (Lago-Mare biofacies). In other respects, the palaeoenvironment of p-ev1 deposits, mostly represented by resedimented evaporitic deposits or barren laminated sediments, hasn't been thoroughly clarified yet. The aim of the present study, dealing with messinian p-ev1 deposits from Marche and Maiella successions, is to provide more details in the definition of the environment developed during the early post-evaporitic phase. Since the lamination and the absence of benthic fauna suggest the occurrence of anoxic conditions, the following indirect proxies for the detection of organic matter have been investigated: 1) sedimentary fabric and microfacies; 2) framboidal pyrite size distribution; 3) natural radioactivity (authigenic uranium values, Th/U ratios). Natural radioactivity has been achieved through gamma spectrometry, with field and laboratory specific techniques. In the Maccarone section (Marche region), p-ev1 deposits are constituted by: barren greyish shales; laminated black shales interbedded with calcitic and ankeritic horizons; thin intercalations of sandstones. Organic-matter and framboidal pyrite commonly occur. Size analysis of framboids populations yielded a mean diameter of 4÷8 m, typical of disaerobic facies. Microfacies analysis yielded also the presence of crystals aggregates of barite, up to 50 m in size, and of isolated detrital (silicilastic) crystals. Without considering γ-ray values of the volcaniclastic layer (52-65 Cps) occurring within the p-ev1 interval, black shales horizons revealed the maximum natural radioactivity (NRD of about 50 Cps) recorded inthe studied section. Lower γ-activity characterizes the calcitic layers (i.e. "Colombacci") and the ankerites. Field NRD spectra acquired on different lithologies, showed variable contributions of 238U, 232Th and 40K. Both the blue-greyish shales and the black shales are characterized by total NRD related to the three main radioelements: 40K is associated to abundant 238U content (Thppm/Uppm 1). The 238U content is primarily referable to processes of organic matter enrichment (authigenic uranium) and secondarily to the input of detrital grains. In contrast, 40K and 232Th are entirely ascribed to the clastic fraction. P-ev1 deposits from Maiella section consist of thinly-laminated grey-brownish pelites, enclosing carbonatic lenses and interrupted horizons. The pelitic fraction contains Fe-Mn-Ni encrustated micronodules. The carbonate portion is made up of locally brecciated calcitic limestones, associated with calcitic concretions and discontinuous laminae. Traces of organic matter and bitumen have been observed in thin section. Framboidal pyrite occurs both as single element and as aggregate, reaching dimensions up to about 10 m. Barite and celestite occur as well. NRD measurements yielded high values of radioactivity both in carbonates (20-63 Cps) and in terrigenous sediments (21-70 Cps). Limestones NRD-spectra showed a 238U-dominant (5 ppm in content) radioactivity. 238U is totally referable to an authigenic origin, since the γ-activity of limestones is devoid of contributions from 40K and 232Th (proxies for the detritic fraction). In the latest Messinian frame, authigenic uranium, barite, ankerite, Fe-Mn oxyhydroxide and framboidal pyrite indicate strongly palaeoredox conditions (from disaerobic to fully anoxic). In particular, with respect to NRD data, this peculiar environment is confirmed by the Th/U ratio, mostly

6. North wall and east end of air brake shop ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. North wall and east end of air brake shop section of roundhouse at center. East end of boiler shop section of roundhouse to the right of air brake shop. East end of blacksmith shop section of roundhouse at far right. View to southeast. - Duluth & Iron Range Rail Road Company Shops, Roundhouse, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

Assessment of complex water pollution with heavy metals and Pyrethroid pesticides on transcript levels of metallothionein and immune related genes.

PubMed

Ghazy, Haneen A; Abdel-Razek, Mohamed A S; El Nahas, Abeer F; Mahmoud, Shawky

2017-09-01

Alteration of immunological function of an aquatic organism can be used as an indicator for evaluating the direct effect of exposure to pollutants. The aim of this work is to assess the impact of complex water pollution with special reference to Pyrethroid pesticides and heavy metals on mRNA transcript levels of Metallothionine and some immune related genes of Nile tilapia (Oreochromas Niloticus). Residues of six heavy metals and six Pyrethroid were assessed in water as well as fish tissues at three different sites of Lake Burullus, located at Northern Egypt. Variations of water physicochemical properties associated with different levels of heavy metals at the three different sections were recorded. Tissue residues of Fe, Mn and Zn, Cu, Ni exceed water levels in contrast to elevated water level of Pb. All assessed Pyrethroids are detected in fish tissue samples with higher concentration (3-42 folds) than that found in water samples especially Cypermethrin. Significant down-regulation of expression levels of metallothionein (MT) at the three sections of the lake was observed. The expression of immune related genes (IgM) and inflammatory cytokines (TNF, IL.8 and IL.1) were affected. IgM and TNF were significantly down-regulated at eastern and western section of the lake; meanwhile the expression of IL8 is down regulated at the three sections of the lack. IL1 was significantly up-regulated at eastern and middle sections. We conclude that, variable gene expression of MT and immune-related genes at the three sections of the lack impose different response to complex water pollution in relation to variable aquatic environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Manganese speciation in Diplodon chilensis patagonicus shells: a XANES study

NASA Astrophysics Data System (ADS)

Soldati, A. L.; Vicente-Vilas, V.; Goettlicher, J.; Jacob, D. E.

2009-04-01

In addition to other types of climate archives, biogenic skeletons of a variety of different organisms (i.e. shells of bivalves, skeletal hard parts of corals or sponges) are increasingly used for high-resolution climate reconstructions. Bivalves are particularly suited for such analyses because they are geographically broadly distributed and have been shown to record climate and environmental information reliably and over long time intervals. Variation of environmental parameters such as food supply, substratum type, salinity, illumination, temperature, concentration of dissolved oxygen or oxygen/carbon dioxide ratio, among others, may affect growth pattern, shell structure, mineralogy, isotopic fractionation and chemistry. Thus, shell features, minor and trace element composition patterns and isotopic signals may serve as an archive of environmental history. In turn, palaeoclimatic parameters such as ambient temperature, precipitation gradients, seawater salinity and primary production can be reconstructed from the shells by means of sclerochronological and geochemical methods. However, the distribution of minor and trace elements in the biominerals is not only influenced by the environment or vital effects, but also by intrinsic biomineralisation parameters like the carbonate polymorphism and the mineral habit (Soldati et al., 2008a). Generally, it is assumed that the X2+ ions are replacing the Ca2+ ion in the calcium carbonate (CaCO3) structure, but newest findings show that amorphous (or disordered) phases may play a role in hosting some of the elements use as proxies (Meibom et al., 2008; and Finch and Allison, 2007). In this work we focused on the freshwater clam Diplodon chilensis patagonicus, a widely distributed inhabitant of lakes and rivers in southern South America. Thanks to its long life span and seasonal growth Diplodon mussels exhibit excellent characteristics to construct an accurate chronological archive, with time windows of up to around a century, resolving the environmental signal annually and even seasonally (Soldati et al., 2008b). High resolution trace elemental analysis by LA-ICPMS and EPMA in the shells show that elements like Mg and Mn are related to the seasonal pattern and can be enriched along the organic-rich annual shell growth lines. Thus, these elements could possibly be bound organically instead of occupying a defined site in the crystal lattice of the calcium carbonate phase. LA-ICP-MS results show that Mn concentrations in these Diplodon shells range between 1000-300 g/g and 100-10 g/g and that the areas of enrichment are in the micrometer range. Raman and XRD measurements at high spatial resolution failed in recognizing whether the Mn is in carbonate solid solution or not. Therefore, speciation techniques like X-ray absorption fine structure (XAFS) spectroscopy with a high lateral resolution are required to address this question. Prior to XAFS spectroscopy the samples were mapped with the intensity of the Mn Kα fluorescence emission line in order to locate the Mn rich areas of interest. Because of the Mn concentrations in the sub % range the XAFS spectra at the positions of interest have been recorded in fluorescence mode using a 7 element Si(Li) detector. This study focuses on the near edge (XANES: X-ray absorption near edge structure) part of the spectra. For data evaluation, XANES spectra of reference substances were additionally measured in order to get first hints to Mn valence and bonding. As standards were used Mn and Mn rich carbonates, Mn oxides with Mn in different oxidation states, and Mn in organic compounds (Mn-porphyrin and Mn-acetate). The XAFS measurements have been carried out at the SUL-X beamline of the synchrotron radiation source ANKA of the Forschungszentrum Karlsruhe. Data evaluation is ongoing. References MEIBOM, A., CUIF, J.P., HOULBREQUE, F., MOSTEFAOUI, S., DAUPHIN, Y., MEIBOM; K.L. & DUNBAR, R. (2008). Compositional variations at ultra-structure length scales in coral skeleton. Geochimica et Cosmochimica Acta 72: 1555-1569. FINCH, A.A. & ALLISON, N. (2007). Coordination of Sr and Mg in calcite and aragonite. Mineralogical Magazine 71: 539-552. SOLDATI A.L., JACOB D.E., WEHRMEISTER, U. & HOFMEISTER, W. (2008a). Structural characterization and chemical composition of aragonite and vaterite in freshwater cultured pearls. Mineralogical Magazine 72: 577-590. SOLDATI A.L., JACOB D., SCHÖNE B.R., BIANCHI M.M. & HAJDUK A. (2008b). Seasonal periodicity of growth and composition in valves of Diplodon chilensis patagonicus (D'Orbigny, 1835). Journal of Molluscan Studies, doi:10.1093/mollus/eyn044.

Nanocrystalline hydroxyapatite enriched in selenite and manganese ions: physicochemical and antibacterial properties

NASA Astrophysics Data System (ADS)

Kolmas, Joanna; Groszyk, Ewa; Piotrowska, Urszula

2015-07-01

In this work, we used the co-precipitation method to synthesize hydroxyapatite (Mn-SeO3-HA) containing both selenium IV (approximately 3.60 wt.%) and manganese II (approximately 0.29 wt.%). Pure hydroxyapatite (HA), hydroxyapatite-containing manganese (II) ions (Mn-HA), and hydroxyapatite-containing selenite ions alone (SeO3-HA), prepared with the same method, were used as reference materials. The structures and physicochemical properties of all the obtained samples were investigated. PXRD studies showed that the obtained materials were homogeneous and consisted of apatite phase. Introducing selenites into the hydroxyapatite crystals considerably affects the size and degree of ordering. Experiments with transmission electron microscopy (TEM) showed that Mn-SeO3-HA crystals are very small, needle-like, and tend to form agglomerates. Fourier transform infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance (ssNMR) were used to analyze the structure of the obtained material. Preliminary microbiological tests showed that the material demonstrated antibacterial activity against Staphylococcus aureus, yet such properties were not confirmed regarding Escherichia coli. PACS codes: 61, 76, 81

Synthesis, characterization and molecular modeling of some transition metal complexes of Schiff base derived from 5-aminouracil and 2-benzoyl pyridine

NASA Astrophysics Data System (ADS)

Abdel-Monem, Yasser K.; Abouel-Enein, Saeyda A.; El-Seady, Safa M.

2018-01-01

Multidentate Schiff base (H2L) ligand results from condensation of 5-aminouracil and 2-benzoyl pyridine and its metal chloride (Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Fe(III), Cr(III), Ru(III), Zr(IV) and Hf(IV)) complexes were prepared. The structural features of the ligand and its metal complexes were confirmed by elemental analyses, spectroscopic methods (IR, UV-Vis, 1H NMR, mass), magnetic moment measurements and thermal studies. The data refer to the ligand coordinates with metal ions in a neutral form and shows different modes of chelation toward the metal atom. All complexes have octahedral skeleton structure, tetrahedrally Mn(II), Ni(II), trigonalbipyramidal Co(II) and square planner Pd(II). Thermal decomposition of complexes as well as the interaction of different types of solvent of crystallization are assigned by thermogravimetric analysis. Molecular modeling of prepared complexes were investigated to study the expected anticancer activities of the prepared complexes. All metal complexes have no interaction except the complexes of Pd(II), Fe(III) and Mn(II).

Biomonitoring air quality during and after a public transportation strike in the center of Uberlândia, Minas Gerais, Brazil by Tradescantia micronucleus bioassay.

PubMed

Pereira, Boscolli Barbosa; de Campos, Edimar Olegário; de Lima, Euclides Antônio Pereira; Barrozo, Marcos Antonio Souza; Morelli, Sandra

2014-03-01

The aim of this study was to address the lack of information concerning the air quality in the city of Uberlândia, Minas Gerais, Brazil. In this study, we conducted an unprecedented experiment involving the in situ biomonitoring of air genotoxicity in the city center during and after a public transportation strike using the Tradescantia micronucleus test. The frequency of micronuclei was significantly higher in the city center compared with the reference site (Mann-Whitney test, p < 0.05), with the highest MN levels being observed during public transport stoppage (Kruskal-Wallis, Dunn p < 0.01). In addition, the multiple linear regression analyses revealed that the low circulation of buses during public transport stoppage and the increase in the concentration of particulate matter from the increased flow of vehicles in the city center during the strike positively influenced the MN frequency. The climatic factors did not change during the biomonitoring period, reflecting the fact that climatic factors did not influence the MN frequency.

The Evaluation of Triphenyl Phosphate as a Flame Retardant Additive to Improve the Safety of Lithium-Ion Battery Electrolytes

NASA Technical Reports Server (NTRS)

Smart, M. C.; Krause, F. C.; Hwang, C.; West, W. C.; Soler, J.; Prakash, G. K. S.; Ratnakumar, B. V.

2011-01-01

With the intent of improving the safety characteristics of lithium ion cells, electrolytes containing flame retardant additives have been investigated. A number of triphenyl phosphate-containing electrolytes were evaluated in both coin cells and experimental three electrode lithium-ion cells (containing reference electrodes). A number of chemistries were investigated, including MCMB carbon/LiNi(0.8)Co(0.2)O2 (NCO), graphite/LiNi(0.8)Co(0.15)Al(0.05)O2 (NCA), Li/Li(Li(0.17)Ni(0.25)Mn(0.58))O2, Li/LiNiMnCoO2 (NMC) and graphite/LiNiMnCoO2 (NMC), to study the effect that different electrolyte compositions have upon performance. A wide range of TPP-containing electrolytes were demonstrated to have good compatibility with the C/NCO, C/NCA, and Li/NMC systems, however, poor performance was initially observed with the high voltage C/NMC system. This necessitated the development of improved electrolytes with stabilizing additives, leading to formulations containing lithium bis(oxalato)borate (LiBOB) that displayed substantially improved performance.

Fluorescent, MRI, and colorimetric chemical sensors for the first-row d-block metal ions.

PubMed

Zhu, Hao; Fan, Jiangli; Wang, Benhua; Peng, Xiaojun

2015-07-07

Transition metals (d-blocks) are recognized as playing critical roles in biology, and they most often act as cofactors in diverse enzymes; however, improper regulation of transition metal stores is also connected to serious disorders. Therefore, the monitoring and imaging of transition metals are significant for biological research as well as clinical diagnosis. In this article, efforts have been made to review the chemical sensors that have been developed for the detection of the first-row d-block metals (except Cu and Zn): Cr, Mn, Fe, Co, and Ni. We focus on the development of fluorescent sensors (fall into three classes: "turn-off", "turn-on", and ratiometric), colorimetric sensors, and responsive MRI contrast agents for these transition metals (242 references). Future work will be likely to fill in the blanks: (1) sensors for Sc, Ti, and V; (2) MRI sensors for Cr, Mn, Co, Ni; (3) ratiometric fluorescent sensors for Cr(6+), Mn(2+), and Ni(2+), explore new ways of sensing Fe(3+) or Cr(3+) without the proton interference, as well as extend applications of MRI sensors to living systems.

77 FR 37728 - GMB Mezzanine Capital II, L.P.; Notice Seeking Exemption Under Section 312 of the Small Business...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-22

... SMALL BUSINESS ADMINISTRATION [License No. 05/05-0299] GMB Mezzanine Capital II, L.P.; Notice Seeking Exemption Under Section 312 of the Small Business Investment Act, Conflicts of Interest Notice is hereby given that GMB Mezzanine Capital II, L.P., 50 South Sixth Street, Suite 1460, Minneapolis, MN...

76 FR 18821 - Convergent Capital Partners II, L.P.; Notice Seeking Exemption Under Section 312 of the Small...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-05

... SMALL BUSINESS ADMINISTRATION [License No. 05/05-0293] Convergent Capital Partners II, L.P.; Notice Seeking Exemption Under Section 312 of the Small Business Investment Act, Conflicts of Interest..., Minneapolis, MN 55441, a Federal Licensee under the Small Business Investment Act of 1958, as amended (``the...

Cross Sections of P-Induced Reactions up to 100 MeV for the Interpretation of Solar Cosmic Ray Produced Nuclides

NASA Astrophysics Data System (ADS)

Schiekel, T.; Rosel, R.; Herpers, U.; Bodemann, R.; Michel, R.; Dittrich, B.; Hofmann, H. J.; Suter, M.; Wolfli, W.; Holmqvist, B.; Conde, H.; Malmborg, P.

1992-07-01

Integral excitation functions for the production of residual nuclides by proton-induced reactions are the basic data for an accurate modelling of the interactions of solar cosmic ray (SCR) particles with extraterrestrial matter. Due to the relatively low energies (<200 MeV/A) of SCR particles the production of nuclear active secondary particles can be widely neglected and theoretical production rate depth profiles can be calculated by simply folding the depth dependent SCR spectra with thin target cross sections of the underlying nuclear reactions. The accuracy of such calculations exclusively depends on the quality of the available cross sections. For many nuclides, in particular for long-lived radionuclides and stable rare gas isotopes, the exis- ting cross section database is neither comprehensive nor reliable. Therefore, we started a series of experiments to improve this situation. Eighteen elements (C, N as Si3N4, O as SiO2, Mg, Al, Si, Ti, V, Mn as Mn/Ni-alloy, Fe, Co, Ni, Cu, Zr, Nb, Rh, Ba as Ba-contai- ning glass, and Au) were irradiated with 94 and 99 MeV protons at the external beam of the TSL-cyclotron at Uppsala. Cross sections were determined using the stacked foil technique. Beam monitoring was done by investigating the production of ^22Na from Al, for which evaluated cross sections exist. Residual nuclides were measured by X-, gamma- and accelerator-mass spectrometry. In order to check the quality of our experimental procedure some target elements (22 <= Z <= 28) were included in the new exper- iments, which had been formerly irradiated at Julich, at Louvain La Neuve, and at IPN Orsay. Comparisons between the earlier measurements (1,2) and the new cross sections showed excellent agreement. Up to now, cross sections were measured for more than 120 different reactions. Here, we report on the results obtained for the target elements C, N, O, Mg, Al, and Si. The status of experimental excitation functions for the production of some radionuclides relevant for SCR interactions with terrestrial and extraterrestrial matter, i.e., ^7Be and ^10Be from C, N, O, Mg, Al, and Si and ^22Na and ^26Al from Mg, Al, and Si, is discussed in detail. In order to investigate whether theoretical calculations can be used to supply the necessary cross sections for SCR model calcu- lations, a theoretical analysis of the experimental data is given on the basis of model calculations of equilibrium and pre-equilibrium reactions for light target elements. The new data are applied to model calculations of the production of SCR-produced nuclides in lunar surface materials and in meteorites. Acknowledgement: This work was supported by the Deutsche Forschungsgemeinschaft and by the Swiss National Science Foundation. References: (1) Michel et al. (1984) J. Geophys Res. 89, B673- B684. (2) Michel R. et al. (1985) Nucl. Phys. A441, 617-639.

Temporal and spatial variability of Fe and Mn in perched groundwater flowing through weathered argillite underlying a steep forested hillslope

NASA Astrophysics Data System (ADS)

Kim, H.; Bishop, J. K.

2013-12-01

Groundwater flowing through weathered bedrock dictates the runoff chemistry to streams in many catchments yet; its chemical evolution has been rarely documented. In particular, observations of Fe and Mn dynamics in groundwater are extremely challenging due to their high reactivity. To preserve the sample integrity for these elements we have developed a new sampling scheme that is applicable to autosamplers; a gravitational filtration system (GFS). GFS is capable of filtering samples by gravity within 30 minutes after the sampling. The GFS samples showed a good agreement with reference samples, which were collected following the standard sampling method for trace metals (i.e. immediate filtration and acidification). Since October 2011, GFS has been employed to monitor Fe and Mn in perched groundwater that moves through weathered argillite in an intensively instrumented hillslope (Rivendell), in the Angelo Coast Range Reserve. The study site is located at the headwaters of the Eel River, northern California, characterized by a typical coastal Californian Mediterranean climate. We collected groundwater samples at 3 wells along the hillslope (upslope (W10), mid-slope (W3) and near the creek (W1)) with 1-3 day intervals. Additionally, rainwater and throughfall samples were collected at a meadow near the hillslope and at the middle of the hillslope, respectively. The results from our observations indicate that Fe and Mn exhibit distinct spatial and temporal behavior under variable hydrologic conditions. The concentrations of Fe in throughfall vs. rainwater were similar (0.45μM vs. 0.49μM), but Mn in throughfall was 10-fold higher than that in rainwater (1.2 μM vs. 0.1 μM). In the early rainy season, W10's water table was deep (-18m) and Fe and Mn in W10 were 30-150 nM and 1-2 μM, respectively. As the rainy season proceeds, W10's water table rose by 4-6m, indicating the arrival of new water. At this time, Mn in W10 decreased to ~0.1 μM, synchronizing with the water table rise, and remained unchanged throughout the season. In contrast, Fe slowly declined to <10nM for this high water table regime. During the summer recession limb, Fe and Mn concentrations in W10 began to increase. During the dry summer, the concentrations of Fe and Mn at W3 were 2-3μM and 15-20 μM, respectively. At the beginning of the rainy seasons, the W3 water table slowly rose (<1 m) and both Fe and Mn decreased by 10-fold. The concentrations of Fe and Mn decreased to 20-70nM and 0.1 μM, respectively, when W3's water table became highly dynamic and fluctuated about 4 m. At W1, Fe and Mn remained in the 50-100nM and 5-10 μM ranges, respectively; however, the water table was extremely responsive to rainfall inputs. Mn in W1 was briefly diluted to <0.1 μM during large rainstorms and rebounded within several days. In the late summer of 2012, Fe and Mn in W1 increased up to 2-6 μM and 80 μM, respectively. These high-frequency observations of Fe and Mn will provide insight into the biogeochemical cycles of redox sensitive elements in upland terrains, allowing for better quantitative estimation of these elemental fluxes.

Development of Bifunctional Gadolinium-Labeled Superparamagnetic Nanoparticles (Gd-MnMEIO) for In Vivo MR Imaging of the Liver in an Animal Model.

PubMed

Kuo, Yu-Ting; Chen, Chiao-Yun; Liu, Gin-Chung; Wang, Yun-Ming

2016-01-01

Liver tumors are common and imaging methods, particularly magnetic resonance imaging (MRI), play an important role in their non-invasive diagnosis. Previous studies have shown that detection of liver tumors can be improved by injection of two different MR contrast agents. Here, we developed a new contrast agent, Gd-manganese-doped magnetism-engineered iron oxide (Gd-MnMEIO), with enhancement effects on both T1- and T2-weighted MR images of the liver. A 3.0T clinical MR scanner equipped with transmit/receiver coil for mouse was used to obtain both T1-weighted spoiled gradient-echo and T2-weighted fast spin-echo axial images of the liver before and after intravenous contrast agent injection into Balb/c mice with and without tumors. After pre-contrast scanning, six mice per group were intravenously injected with 0.1 mmol/kg Gd-MnMEIO, or the control agents, i.e., Gd-DTPA or SPIO. The scanning time points for T1-weighted images were 0.5, 5, 10, 15, 20, 25, and 30 min after contrast administration. The post-enhanced T2-weighted images were then acquired immediately after T1-weighted acquisition. We found that T1-weighted images were positively enhanced by both Gd-DTPA and Gd-MnMEIO and negatively enhanced by SPIO. The enhancement by both Gd-DTPA and Gd-MnMEIO peaked at 0.5 min and gradually declined thereafter. Gd-MnMEIO (like Gd-DTPA) enhanced T1-weighted images and (like SPIO) T2-weighted images. Marked vascular enhancement was clearly visible on dynamic T1-weighted images with Gd-MnMEIO. In addition, the T2 signal was significantly decreased at 30 min after administration of Gd-MnMEIO. Whereas the effects of Gd-MnMEIO and SPIO on T2-weighted images were similar (p = 0.5824), those of Gd-MnMEIO and Gd-DTPA differed, with Gd-MnMEIO having a significant T2 contrast effect (p = 0.0086). Our study confirms the feasibility of synthesizing an MR contrast agent with both T1 and T2 shortening effects and using such an agent in vivo. This agent enables tumor detection and characterization in single liver MRI sections.

Inadequate dietary intake of minerals: prevalence and association with socio-demographic and lifestyle factors.

PubMed

Sales, Cristiane H; Fontanelli, Mariane de M; Vieira, Diva A S; Marchioni, Dirce M; Fisberg, Regina M

2017-01-01

This cross-sectional, population-based study aimed to estimate the prevalence of dietary mineral inadequacies among residents in urban areas of Sao Paulo, to identify foods contributing to mineral intake and to verify possible associations between socio-demographic and lifestyle factors and mineral intake. Data were obtained from the 2008 Health Survey of Sao Paulo (n 1511; mean age 43·6 (sd 23·2), range 14-97 years). Dietary intake of minerals was measured using two 24-h dietary recalls. Socio-demographic and lifestyle data were collected. The prevalence of inadequate intake was estimated according to Dietary Reference Intakes methods. Associations between mineral intake and baseline factors were determined using multiple linear regression. Na, Ca and Mg showed the highest dietary inadequacies. Some age/sex groups had lower intakes of P, Zn, Cu and Se. Rice, beans and bread were the main foods contributing towards mineral intake. Female sex was negatively associated with K, Na, P, Mg, Zn and Mn intakes. All age groups were positively associated with the intakes of K, P, Mg and Mn. Family income above one minimum wage was positively associated with Se intake. Living in a household whose head completed ≥10 years of education was positively associated with Ca and negatively associated with Na intake. Former smoker status was negatively associated with Ca intake. Current smoker status was inversely associated with K, Ca, P and Cu intakes. Sufficient physical activity was positively associated with K, Ca and Mg intakes. Overall, the intakes of all major minerals were inadequate and were influenced by socio-demographic and lifestyle factors.

Freeze-Fracture Ultrastructure of Thylakoid Membranes in Chloroplasts from Manganese-Deficient Plants

PubMed Central

Simpson, David J.; Robinson, Simon P.

1984-01-01

Leaves from spinach (Spinacia oleracea L. cv Hybrid 102) plants grown in Mn-deficient nutrient solution were characterized by chlorosis, lowered chlorophyll a/b ratio and reduced electron transport. There were characteristic changes in room temperature fluorescence induction kinetics with increased initial yield (Fo) and decreased variable fluorescence (Fv). The fluorescence yield after the maximum fell rapidly to a level below Fo. The shape of the rise from Fo to the maximum was altered and the size of photosystem II units increased, as measured by half-rise time of Fv in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The Mn-deficient leaves were harvested before necrosis, when thin section electron microscopy revealed no disorganization of the thylakoid system. Thylakoid membranes were examined by freeze-fracture electron microscopy. The effect of Mn-deficiency was the specific loss of three-quarters of the particles from the endoplasmic fracture face of appressed thylakoids (EFs). Mn-deficient leaves were restored to near normal 2 days after application of exogenous Mn to the nutrient solution. It is concluded that the loss of most, but not all, functional photosystem II reaction centers from grana, with no alteration in light-harvesting complex or photosystem I, is responsible for the fluorescence and functional properties observed. The response of thylakoids to Mn deficiency shows that there is a fundamental difference in composition and function of stacked and unstacked endoplasmic fracture particles. The stacked endoplasmic fracture particle probably contains, in close association, the photosystem II reaction center and also the Mn-containing polypeptide, the 3-(3,4-dichlorophenyl)-1,1-dimethylurea-binding protein, and all electron transport components in between. Images Fig. 3 Fig. 4 Fig. 5 PMID:16663491

Asymmetric carbon nanotube-MnO2 two-ply yarn supercapacitors for wearable electronics

NASA Astrophysics Data System (ADS)

Su, Fenghua; Miao, Menghe

2014-04-01

Strong and flexible two-ply carbon nanotube yarn supercapacitors are electrical double layer capacitors that possess relatively low energy storage capacity. Pseudocapacitance metal oxides such as MnO2 are well known for their high electrochemical performance and can be coated on carbon nanotube yarns to significantly improve the performance of two-ply carbon nanotube yarn supercapacitors. We produced a high performance asymmetric two-ply yarn supercapacitor from as-spun CNT yarn and CNT@MnO2 composite yarn in aqueous electrolyte. The as-spun CNT yarn serves as negative electrode and the CNT@MnO2 composite yarn as positive electrode. This asymmetric architecture allows the operating potential window to be extended from 1.0 to 2.0 V and results in much higher energy and power densities than the reference symmetric two-ply yarn supercapacitors, reaching 42.0 Wh kg-1 at a lower power density of 483.7 W kg-1, and 28.02 Wh kg-1 at a higher power density of 19 250 W kg-1. The asymmetric supercapacitor can sustain cyclic charge-discharge and repeated folding/unfolding actions without suffering significant deterioration of specific capacitance. The combination of high strength, flexibility and electrochemical performance makes the asymmetric two-ply yarn supercapacitor a suitable power source for flexible electronic devices for applications that require high durability and wearer comfort.

Size distribution, characteristics and sources of heavy metals in haze episode in Beijing.

PubMed

Duan, Jingchun; Tan, Jihua; Hao, Jiming; Chai, Fahe

2014-01-01

Size segragated samples were collected during high polluted winter haze days in 2006 in Beijing, China. Twenty nine elements and 9 water soluble ions were determined. Heavy metals of Zn, Pb, Mn, Cu, As, Cr, Ni, V and Cd were deeply studied considering their toxic effect on human being. Among these heavy metals, the levels of Mn, As and Cd exceeded the reference values of National Ambient Air Quality Standard (GB3095-2012) and guidelines of World Health Organization. By estimation, high percentage of atmospheric heavy metals in PM2.5 indicates it is an effective way to control atmospheric heavy metals by PM2.5 controlling. Pb, Cd, and Zn show mostly in accumulation mode, V, Mn and Cu exist mostly in both coarse and accumulation modes, and Ni and Cr exist in all of the three modes. Considering the health effect, the breakthrough rates of atmospheric heavy metals into pulmonary alveoli are: Pb (62.1%) > As (58.1%) > Cd (57.9%) > Zn (57.7%) > Cu (55.8%) > Ni (53.5%) > Cr (52.2%) > Mn (49.2%) > V (43.5%). Positive matrix factorization method was applied for source apportionment of studied heavy metals combined with some marker elements and ions such as K, As, SO4(2-) etc., and four factors (dust, vehicle, aged and transportation, unknown) are identified and the size distribution contribution of them to atmospheric heavy metals are discussed.

Bright metal coatings from sustainable electrolytes: the effect of molecular additives on electrodeposition of nickel from a deep eutectic solvent.

PubMed

Abbott, Andrew P; Ballantyne, Andrew; Harris, Robert C; Juma, Jamil A; Ryder, Karl S

2017-01-25

Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the [111] orientation whereas DMH and BA direct crystal growth to the [220] orientation.

Geochemical analysis of soils and sediments, Coeur d'Alene drainage basin, Idaho: sampling, analytical methods, and results

USGS Publications Warehouse

Box, Stephen E.; Bookstrom, Arthur A.; Ikramuddin, Mohammed; Lindsay, James

2001-01-01

(Fe), manganese (Mn), arsenic (As), and cadmium (Cd). In general inter-laboratory correlations are better for samples within the compositional range of the Standard Reference Materials (SRMs) from the National Institute of Standards and Technology (NIST). Analyses by EWU are the most accurate relative to the NIST standards (mean recoveries within 1% for Pb, Fe, Mn, and As, 3% for Zn and 5% for Cd) and are the most precise (within 7% of the mean at the 95% confidence interval). USGS-EDXRF is similarly accurate for Pb and Zn. XRAL and ACZ are relatively accurate for Pb (within 5-8% of certified NIST values), but were considerably less accurate for the other 5 elements of concern (10-25% of NIST values). However, analyses of sample splits by more than one laboratory reveal that, for some elements, XRAL (Pb, Mn, Cd) and ACZ (Pb, Mn, Zn, Fe) analyses were comparable to EWU analyses of the same samples (when values are within the range of NIST SRMs). These results suggest that, for some elements, XRAL and ACZ dissolutions are more effective on the matrix of the CdA samples than on the matrix of the NIST samples (obtained from soils around Butte, Montana). Splits of CdA samples analyzed by CHEMEX were the least accurate, yielding values 10-25% less than those of EWU.

13. Detail of doubledoor opening between machine shop section of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Detail of double-door opening between machine shop section of roundhouse and engine house section of roundhouse. Engine house visible through rectangular opening. At one time the opening extended to the intrados of the arch above the doorway, allowing railroad engines to fit inside the machine shop. View to east. - Duluth & Iron Range Rail Road Company Shops, Roundhouse, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

Reconstruction of the Nd isotope composition of seawater on epicontinental seas: Testing the potential of Fe-Mn oxyhydroxide coatings on foraminifera tests for deep-time investigations

NASA Astrophysics Data System (ADS)

Charbonnier, Guillaume; Pucéat, Emmanuelle; Bayon, Germain; Desmares, Delphine; Dera, Guillaume; Durlet, Christophe; Deconinck, Jean-François; Amédro, Francis; Gourlan, Alexandra T.; Pellenard, Pierre; Bomou, Brahimsamba

2012-12-01

The Fe-Mn oxide fraction leached from deep-sea sediments has been increasingly used to reconstruct the Nd isotope composition of deep water masses, that can be used to track changes in oceanic circulation with a high temporal resolution. Application of this archive to reconstruct the Nd isotope composition of bottom seawater in shallow shelf environments remained however to be tested. Yet as the Nd isotope composition of seawater on continental margins is particularly sensitive to changes in erosional inputs, establishment of neritic seawater Nd isotope evolution around areas of deep water formation would be useful to discriminate the influence of changes in oceanic circulation and in isotopic composition of erosional inputs on the Nd isotope record of deep waters. The purpose of this study is to test the potential of Fe-Mn coatings leached from foraminifera tests to reconstruct the Nd isotope composition of seawater in shelf environments for deep-time intervals. Albian to Turonian samples from two different outcrops have been recovered, from the Paris Basin (Wissant section, northern France) and from the Western Interior Seaway (Hot Spring, South Dakota, USA), that were deposited in epicontinental seas. Rare Earth Element (REE) spectra enriched in middle REEs in the foraminifera leach at Wissant highlight the presence of Fe-Mn oxides. The similarity of the Nd isotopic signal of the Fe-Mn oxide fraction leached from foraminifera tests with that of fish teeth suggests that Fe-Mn oxides coating foraminifera can be good archives of shelf bottom seawater Nd isotopic composition. Inferred bottom shelf water Nd isotope compositions at Wissant range from -8.5 to -9.7 ɛ-units, about 1.5-2 ɛ-units higher than that of the contemporaneous local detrital fraction. At Hot Spring, linear REE spectra characterizing foraminifera leach may point to an absence of authigenic marine Fe-Mn oxide formation in this area during the Late Cenomanian-Early Turonian, consistent with dysoxic to anoxic conditions at Hot Spring, contemporaneous to an Oceanic Anoxic Event. The similarity of the Nd isotopic signal of the carbonate matrix of foraminifera with that of fish teeth suggests that it records the Nd isotope composition of bottom shelf seawater as well. Inferred bottom shelf water Nd isotope compositions at Hot Spring are quite radiogenic, between -7 and -6 ɛ-units, about 2.5-4 ɛ-units higher than that of the contemporaneous local detrital fraction. In contrast, in both sections Fe-Mn oxides leached directly from the decarbonated sediment tend to yield a less radiogenic Nd isotopic composition, typically between 0.2 and 0.8 ɛ-units lower, that is intermediate between that of fish teeth and of the detrital fraction. This suggests the contribution of pre-formed continental Fe-Mn oxides to the Nd isotopic signal, along with authigenic marine oxides, or a detrital contamination during leaching.

Evaluation Plan for the Computerized Adaptive Vocational Aptitude Battery

DTIC Science & Technology

1982-05-15

Educational and Psychological Tests published by the American Psychological Association, the American Educational Research Association, and the National...Psychometric Society Meetings, May 1981. References 71 American Psychological Association. Standards for educational and psychological tests . Washington, D.C...Methods Program, Dept. of Psychology , Uni- versity of Minnesota, MN, September, 1981. Koch, W.R. & Reckase, M.D. A live tailored testing comparison study

Photopyroelectric spectroscopic studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) ceramics.

PubMed

Rizwan, Zahid; Zakaria, Azmi; Ghazali, Mohd Sabri Mohd

2011-01-01

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.

Photopyroelectric Spectroscopic Studies of ZnO-MnO2-Co3O4-V2O5 Ceramics

PubMed Central

Rizwan, Zahid; Zakaria, Azmi; Ghazali, Mohd Sabri Mohd

2011-01-01

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO2 + 0.4Co3O4 + xV2O5), x = 0–1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300–800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (Eg) was 2.11 eV for 0.3 mol% V2O5 at a sintering temperature of 1025 °C as determined from the plot (ρhυ)2 versus hυ. With a further increase in V2O5, the value of Eg was found to be 2.59 eV. Steepness factor ‘σA’ and ‘σB’, which characterize the slope of exponential optical absorption, is discussed with reference to the variation of Eg. XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively. PMID:21673911

107. DAM EARTH DIKE SUBMERSIBLE DAMS PLANS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

107. DAM - EARTH DIKE - SUBMERSIBLE DAMS - PLANS & SECTIONS (ML-8-52/3-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

78 FR 4459 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-22

... investigation resulting in-- (A) An affirmative determination of serious injury or threat thereof under section..., MN...... Inc., General Mills, Inc., Manpower, Certes, Salo, etc. The investigation revealed that the...

Genotoxicity of TiO2 nanoparticles assessed by mini-gel comet assay and micronucleus scoring with flow cytometry.

PubMed

Di Bucchianico, Sebastiano; Cappellini, Francesca; Le Bihanic, Florane; Zhang, Yuning; Dreij, Kristian; Karlsson, Hanna L

2017-01-01

The widespread production and use of nanoparticles calls for faster and more reliable methods to assess their safety. The main aim of this study was to investigate the genotoxicity of three reference TiO 2 nanomaterials (NM) within the frame of the FP7-NANoREG project, with a particular focus on testing the applicability of mini-gel comet assay and micronucleus (MN) scoring by flow cytometry. BEAS-2B cells cultured under serum-free conditions were exposed to NM100 (anatase, 50-150nm), NM101 (anatase, 5-8nm) and NM103 (rutile, 20-28nm) for 3, 24 or 48h mainly at concentrations 1-30 μg/ml. In the mini-gel comet assay (eight gels per slide), we included analysis of (i) DNA strand breaks, (ii) oxidised bases (Fpg-sensitive sites) and (iii) light-induced DNA damage due to photocatalytic activity. Furthermore, MN assays were used and we compared the results of more high-throughput MN scoring with flow cytometry to that of cytokinesis-block MN cytome assay scored manually using a microscope. Various methods were used to assess cytotoxic effects and the results showed in general no or low effects at the doses tested. A weak genotoxic effect of the tested TiO 2 materials was observed with an induction of oxidised bases for all three materials of which NM100 was the most potent. When the comet slides were briefly exposed to lab light, a clear induction of DNA strand breaks was observed for the anatase materials, but not for the rutile. This highlights the risk of false positives when testing photocatalytically active materials if light is not properly avoided. A slight increase in MN formation for NM103 was observed in the different MN assays at the lower doses tested (1 and 5 μg/ml). We conclude that mini-gel comet assay and MN scoring using flow cytometry successfully can be used to efficiently study cytotoxic and genotoxic properties of nanoparticles. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society.

Genotoxicity of TiO2 nanoparticles assessed by mini-gel comet assay and micronucleus scoring with flow cytometry

PubMed Central

Di Bucchianico, Sebastiano; Cappellini, Francesca; Le Bihanic, Florane; Zhang, Yuning; Dreij, Kristian; Karlsson, Hanna L.

2017-01-01

The widespread production and use of nanoparticles calls for faster and more reliable methods to assess their safety. The main aim of this study was to investigate the genotoxicity of three reference TiO2 nanomaterials (NM) within the frame of the FP7-NANoREG project, with a particular focus on testing the applicability of mini-gel comet assay and micronucleus (MN) scoring by flow cytometry. BEAS-2B cells cultured under serum-free conditions were exposed to NM100 (anatase, 50–150nm), NM101 (anatase, 5–8nm) and NM103 (rutile, 20–28nm) for 3, 24 or 48h mainly at concentrations 1–30 μg/ml. In the mini-gel comet assay (eight gels per slide), we included analysis of (i) DNA strand breaks, (ii) oxidised bases (Fpg-sensitive sites) and (iii) light-induced DNA damage due to photocatalytic activity. Furthermore, MN assays were used and we compared the results of more high-throughput MN scoring with flow cytometry to that of cytokinesis-block MN cytome assay scored manually using a microscope. Various methods were used to assess cytotoxic effects and the results showed in general no or low effects at the doses tested. A weak genotoxic effect of the tested TiO2 materials was observed with an induction of oxidised bases for all three materials of which NM100 was the most potent. When the comet slides were briefly exposed to lab light, a clear induction of DNA strand breaks was observed for the anatase materials, but not for the rutile. This highlights the risk of false positives when testing photocatalytically active materials if light is not properly avoided. A slight increase in MN formation for NM103 was observed in the different MN assays at the lower doses tested (1 and 5 μg/ml). We conclude that mini-gel comet assay and MN scoring using flow cytometry successfully can be used to efficiently study cytotoxic and genotoxic properties of nanoparticles. PMID:27382040

Protective effects of antioxidants and anti-inflammatory agents against manganese-induced oxidative damage and neuronal injury.

PubMed

Milatovic, Dejan; Gupta, Ramesh C; Yu, Yingchun; Zaja-Milatovic, Snjezana; Aschner, Michael

2011-11-01

Exposure to excessive manganese (Mn) levels leads to neurotoxicity, referred to as manganism, which resembles Parkinson's disease (PD). Manganism is caused by neuronal injury in both cortical and subcortical regions, particularly in the basal ganglia. The basis for the selective neurotoxicity of Mn is not yet fully understood. However, several studies suggest that oxidative damage and inflammatory processes play prominent roles in the degeneration of dopamine-containing neurons. In the present study, we assessed the effects of Mn on reactive oxygen species (ROS) formation, changes in high-energy phosphates and associated neuronal dysfunctions both in vitro and in vivo. Results from our in vitro study showed a significant (p<0.01) increase in biomarkers of oxidative damage, F(2)-isoprostanes (F(2)-IsoPs), as well as the depletion of ATP in primary rat cortical neurons following exposure to Mn (500 μM) for 2h. These effects were protected when neurons were pretreated for 30 min with 100 of an antioxidant, the hydrophilic vitamin E analog, trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), or an anti-inflammatory agent, indomethacin. Results from our in vivo study confirmed a significant increase in F(2)-IsoPs levels in conjunction with the progressive spine degeneration and dendritic damage of the striatal medium spiny neurons (MSNs) of mice exposed to Mn (100mg/kg, s.c.) 24h. Additionally, pretreatment with vitamin E (100mg/kg, i.p.) or ibuprofen (140 μg/ml in the drinking water for two weeks) attenuated the Mn-induced increase in cerebral F(2)-IsoPs? and protected the MSNs from dendritic atrophy and dendritic spine loss. Our findings suggest that the mediation of oxidative stress/mitochondrial dysfunction and the control of alterations in biomarkers of oxidative injury, neuroinflammation and synaptodendritic degeneration may provide an effective, multi-pronged therapeutic strategy for protecting dysfunctional dopaminergic transmission and slowing of the progression of Mn-induced neurodegenerative processes. Copyright © 2011 Elsevier Inc. All rights reserved.

Water-extractable magnesium, manganese and copper in leaves and herbs of medicinal plants.

PubMed

Konieczyński, Paweł; Wesołowski, Marek

2012-01-01

Since herbal teas, infusions and decoctions prepared from medicinal plants are popular remedies, it remains a topical question whether these herbal drugs can be treated as sources of essential elements for humans, who often use them in their everyday diet. Therefore, total and water-extractable contents of Mg, Mn and Cu were determined in 41 leaves originating from four botanical species of Plantago lanceolata, Arctostaphyllos uva-ursi, Rubus fruticosus and Betula sp., as well as in 33 samples of herbs represented by three species of Urtica dioica, Hypericum perforatum and Achillea millefolium. The highest level was determined in the case of Mg (in a range from 2.0 to 7.0 mg/g of dry mass [d.m.]), followed by Mn (from 50.0 to 1300.0 mg/kg d.m.), and lowest of all, Cu (from 3.5 to 19.5 mg/kg d.m.). Student's t-test showed that a statistically significant difference exists between samples originating from different plant species regarding the total content and water-extractable forms of Mg, Mn and Cu. By analysis of the relations between elements, it was observed that total level of Cu correlated with total levels of Mg and Mn, which indicates a synergistic interaction between the essential elements under study. With regard to Dietary Reference Intakes (DRIs), the leaves of Rubus fruticosus contained the highest amounts of a water-extractable bioavailable form of Mn, which guarantees from 160 to 200% of the daily requirement of Mn for women and men, respectively. On the other hand, the extract obtained from Urticae folium gave water-extractable Mg in the amount of 76 mg/500 mL, which constitutes about 20% of daily requirement. The plant material richest in water-extractable Cu was Hyperici herba, containing 154.5 microg/500 mL, or 17% of DRI for both sexes.

Evaluation of air sparging and vadose zone aeration for remediation of iron and manganese-impacted groundwater at a closed municipal landfill.

PubMed

Pleasant, Saraya; O'Donnell, Amanda; Powell, Jon; Jain, Pradeep; Townsend, Timothy

2014-07-01

High concentrations of iron (Fe(II)) and manganese (Mn(II)) reductively dissolved from soil minerals have been detected in groundwater monitoring wells near many municipal solid waste landfills. Air sparging and vadose zone aeration (VZA) were evaluated as remedial approaches at a closed, unlined municipal solid waste landfill in Florida, USA. The goal of aeration was to oxidize Fe and Mn to their respective immobile forms. VZA and shallow air sparging using a partially submerged well screen were employed with limited success (Phase 1); decreases in dissolved iron were observed in three of nine monitoring wells during shallow air sparging and in two of 17 wells at VZA locations. During Phase 2, where deeper air sparging was employed, dissolved iron levels decreased in a significantly greater number of monitoring wells surrounding injection points, however no radial pattern was observed. Additionally, in wells affected positively by air sparging (mean total iron (FeTOT) <4.2mg/L, after commencement of air sparging), rising manganese concentrations were observed, indicating that the redox potential of the groundwater moved from an iron-reducing to a manganese-reducing environment. The mean FeTOT concentration observed in affected monitoring wells throughout the study was 1.40 mg/L compared to a background of 15.38 mg/L, while the mean Mn concentration was 0.60 mg/L compared to a background level of 0.27 mg/L. Reference wells located beyond the influence of air sparging areas showed little variation in FeTOT and Mn, indicating the observed effects were the result of air injection activities at study locations and not a natural phenomenon. Air sparging was found effective in intercepting plumes of dissolved Fe surrounding municipal landfills, but the effect on dissolved Mn was contrary to the desired outcome of decreased Mn groundwater concentrations. Copyright © 2014 Elsevier B.V. All rights reserved.

A negative excursion at 14-16 Ma in seawater osmium isotope record: Implications for paleoceanographic studies using Fe-Mn crusts

NASA Astrophysics Data System (ADS)

Goto, K. T.; Tejada, M. L. G.; Suzuki, K.

2017-12-01

Osmium isotope stratigraphy is a recently proposed method to determine the depositional age of Fe-Mn crusts [1, 2]. Seawater Os isotope (187Os/188Os) is roughly determined by the balance of riverine Os inputs with radiogenic value (187Os/188Os = 1.4), and mantle-derived and extra-terrestrial Os inputs with non-radiogenic value (187Os/188Os = 0.12) [3]. Secular variation of global seawater Os isotope (seawater Os isotope curve) has been reconstructed by the analysis of pelagic sediments and exhibits large variations ranging from 0.2 to 1.0 with several negative excursions [3]. Hence, the depositional age of Fe-Mn crusts can be approximately estimated by fitting their Os isotope depth profiles to the seawater Os isotope curve (Osmium isotope stratigraphy). However, this method allows multiple interpretations which are partly due to the lack of high-resolution seawater Os isotope curve [1, 2]. For example, the available seawater Os isotope curve does not exhibit negative anomaly during the Miocene, which contrasts with Os isotope records of Fe-Mn crusts [4]. In the present study, we obtained a high-resolution Os isotope record of Miocene seawater using hemipelagic sediments from IODP Expedition 351 SiteU1438. We found a small negative Os isotope anomaly as low as 0.7 from sediments deposited at 14-16 Ma. The magnitude of this anomaly is similar to those reported from Fe-Mn crusts. Although the extrapolation of Be-10 ages for Fe-Mn crust indicate a younger age for the anomaly ( 11 Ma) [4], we could not find any discernable isotope anomaly at 11 Ma. Our finding is consistent with the timing of major eruption of the Columbia River flood basalts (CFRB) which could provide non-radiogenic Os to seawater at 14-16 Ma [5]. Hence, we suggest that the observed isotope anomaly reflect eruption and subsequent weathering of the CFRB. As the similar Os isotope anomaly is commonly found from Fe-Mn crusts, the Os isotope anomaly at 14-16 Ma could be used as a key event to constrain depositional ages of Fe-Mn crusts. In the presentation, we will also discuss the significance of our findings to paleoceanographic studies using Fe-Mn crusts. References: [1] Klemm et al., 2005 EPSL; [2] Nielsen et al., 2009 EPSL; [3] Peucker-Ehrenbrink & Ravizza, 2012 The Geologic Time Scale 2012; [4] Klemm et al., 2008 EPSL; [5] Hopper et al., 2002 GSA Bulletin

Siderophore-mediated oxidation of Ce and fractionation of HREE by Mn (hydr)oxide-coprecipitation and sorption on MnO2: Experimental evidence for negative Ce-anomalies in abiogenic manganese precipitates

NASA Astrophysics Data System (ADS)

Krämer, Dennis; Tepe, Nathalie; Bau, Michael

2014-05-01

We conducted experiments with Rare Earths and Yttrium (REY), where the REY were sorbed on synthetic manganese dioxide as well as on coprecipitating manganese (hydr)oxide in the presence and absence of the siderophore desferrioxamine-B (DFOB). Siderophores are a group of globally abundant biogenic complexing agents which are excreted by plants and bacteria to enhance the bioavailability of Fe in oxic environments. The model siderophore used in this study, DFOB, is a hydroxamate siderophore occurring in almost all environmental settings with concentrations in the nanomolar to millimolar range and is one of the most thoroughly studied siderophores. In the absence of siderophores and other organic ligands, trivalent Ce is usually surface-oxidized to tetravalent Ce during sorption onto manganese (hydr)oxides. Such Mn precipitates, therefore, often show positive Ce anomalies, whereas the ambient solutions exhibit negative Ce anomalies (Ohta and Kawabe, 2001). In marked contrast, however, REY sorption in the presence of DFOB produces negative Ce anomalies in the Mn precipitates and a distinct and characteristic positive Ce anomaly in the residual siderophore-bearing solution. Furthermore, the heavy REY with ionic radii larger than the radius of Sm are also almost completely prevented from sorption onto the Mn solid phases. Sorption of REY onto Mn (hydr)oxides in the presence of DFOB creates a distinct and pronounced fractionation of Ce and the heavy REY from the light and middle REY. Apart from Ce, which is oxidized in solution by the siderophore, the distribution of the other REY mimics the stability constants for multi-dentate complexes of REY with DFOB, as determined by Christenson & Schijf (2011). Heavier REY are forming stronger complexes (and are hence better "protected" from sorption) than light REY, excluding Ce. Preferential partitioning of Ce into the liquid phase during the precipitation of Mn (hydr)oxides has only rarely been described for natural Mn (hydr)oxides (e.g., Tanaka et al., 2010, Loges et al., 2012). Our experimental results demonstrate that biogenic organic ligands such as hydroxamate siderophores, may produce solutions with positive Ce anomaly (Bau et al., 2013) and may even counteract the surface oxidation of Ce on Mn (hydr)oxides. References Bau, M., Tepe, N., Mohwinkel, D., 2013. Siderophore-promoted transfer of rare earth elements and iron from volcanic ash into glacial meltwater, river and ocean water. Earth Planet. Sci. Lett. 364, 30-36. Christenson E. A. and Schijf J. (2011) Stability of YREE complexes with the trihydroxamate siderophore desferrioxamine B at seawater ionic strength. Geochim. Cosmochim. Acta 75, 7047-7062. Loges, A., Wagner, T., Barth, M., Bau, M., Göb, S., and Markl, G. 2012. Negative Ce anomalies in Mn oxides: The role of Ce4+ mobility during water-mineral interaction. Geochimica and Cosmochimica Acta 86, 296-317 Ohta A. and Kawabe I. (2001) REE (III) adsorption onto Mn dioxide (delta-MnO2) and Fe oxyhydroxide: Ce(III) oxidation by delta-MnO2. Geochim. Cosmochim. Acta 65, 695-703. Tanaka K., Tani Y., Takahashi Y., Tanimizu M., Suzuki Y., Kozai N. and Ohnuki T. (2010) A specific Ce oxidation process during sorption of rare earth elements on biogenic Mn oxide produced by Acremonium sp. strain KR21-2. Geochim. Cosmochim. Acta 74, 5463-5477.

Selective Oxidation of a 0.1C-6Mn-2Si Third Generation Advanced High-Strength Steel During Dew-Point Controlled Annealing

NASA Astrophysics Data System (ADS)

Pourmajidian, Maedeh; McDermid, Joseph R.

2018-03-01

The present study investigates the selective oxidation of a 0.1C-6Mn-2Si medium-Mn advanced high-strength steel during austenization annealing heat treatments as a function of process atmosphere oxygen partial pressure and annealing time. It was determined that the surface oxide growth kinetics followed a parabolic rate law with the minimum rate belonging to the lowest oxygen partial pressure atmosphere at a dew point of 223 K (- 50 °C). The chemistry of the surface and subsurface oxides was studied using STEM + EELS on the sample cross sections, and it was found that the surface oxides formed under the 223 K (- 50 °C) dew-point atmosphere consisted of a layered configuration of SiO2, MnSiO3, and MnO, while in the case of the higher pO2 process atmospheres, only MnO was detected at the surface. Consistent with the Wagner calculations, it was shown that the transition to internal oxidation for Mn occurred under the 243 K (- 30 °C) and 278 K (+ 5 °C) dew-point atmospheres. However, the predictions of the external to internal oxidation for Si using the Wagner model did not correlate well with the experimental findings nor did the predictions of the Mataigne et al. model for multi-element alloys. Investigations of the internal oxide network at the grain boundaries revealed a multilayer oxide structure composed of amorphous SiO2 and crystalline MnSiO3, respectively, at the oxide core and outer shell. A mechanism for the formation of the oxide morphologies observed, based on kinetic and thermodynamic factors, was proposed. It is expected that only the fine and nodule-like MnO oxides formed on the surface of the samples annealed under the 278 K (+ 5 °C) dew-point process atmosphere for 60 and 120 seconds are sufficiently thin and of the desired dispersed morphology to promote reactive wetting by the molten galvanizing bath.

Effects of a fruit-vegetable dietary pattern on oxidative stress and genetic damage in coke oven workers: a cross-sectional study.

PubMed

Xie, Zheng; Lin, Haijiang; Fang, Renfei; Shen, Weiwei; Li, Shuguang; Chen, Bo

2015-05-06

Coke oven workers (COWs) are exposed to high level of genotoxic chemicals that induce oxidative stress and genetic damage. The dietary intake of certain types of foods may reverse these effects. We conducted a cross-sectional study with 51 topside COWs, 79 other COWs, and 67 controls, to assess the effects of dietary patterns on oxidative stress and genetic damage. Compared to the controls, both topside and other COWs had significantly higher urinary 1-hydroxypyrene levels, serum oxidant levels [malondialdehyde, (MDA)], and genetic damage [micronucleus (MN) frequency & 8-oxo-2'-deoxyguanosine (8-OH-dG)], but lower antioxidant levels [superoxide dismutase (SOD) and glutathione peroxidase, (GPx)]. The fruit-vegetable (FV) dietary pattern was positively correlated with serum SOD levels and negative correlated with serum MDA, MN frequency, and urinary 8-OH-dG. COWs with an FV patter in the highest quartile (Q4) had significantly increased antioxidant levels (SOD and GPx) and decreased oxidant levels (MDA) and genetic damage (MN frequency and 8-OH-dG) than those with an FV pattern in the lowest quartile (Q1). Compared to control subjects, COWs had increased oxidative stress and genetic damage. A FV dietary pattern may reverse oxidative stress and genetic damage in COWs.

Formation of the structure and properties of an Mg-Al-Zn-Mn alloy during plastic deformation by rolling

NASA Astrophysics Data System (ADS)

Bozhko, S. A.; Betsofen, S. Ya.; Kolobov, Yu. R.; Vershinina, T. N.

2015-03-01

The laws of formation of an ultrafine structure in an Mg-Al-Zn-Mn alloy (MA5 alloy) under severe plastic deformation have been studied during lengthwise section rolling at a strain e = 1.59. The deformation behavior and the physical factors of anisotropy of yield strength during compression tests in various directions with respect to axis of rolling are analyzed. The role of crystallographic texture and twinning processes in the generation of strength processes and the development of plastic deformation of the alloy is analyzed.

Influence of convection on eutectic microstructure

NASA Technical Reports Server (NTRS)

Baskaran, V.; Eisa, G. F.; Wilcox, W. R.

1985-01-01

When the MnBi-Bi eutectic is directionally solidified, it forms fibers of MnBi in a matrix of bismuth. When the material solidified in space at rates of 30 and 50 cm/hr, the average fiber spacing lambda was about one half of the value obtained in cases in which the same material solidified on earth. Neither an altered temperature gradient nor a fluctuating freezing rate are apparently responsible for the change in lambda, and the possibility is studied that natural convection increases lambda on earth by perturbing the compositional field in the melt ahead of the growing solid. A theoretical analysis is conducted along with some experiments. On the basis of the theoretical results for lamellar growth, it is concluded that the spacing lambda increases with increasing stirring, especially at small freezing rates. The experiments indicate that at low growth rates the cross-sectional area of the MnBi blades increases with increased stirring and with decreased growth rate.

Research on Spectroscopy, Opacity, and Atmospheres

NASA Astrophysics Data System (ADS)

Kurucz, Robert L.; Bell, Barbara

1996-01-01

This line list is a replacement for the Kurucz-Peytremann line list. We have combined all the atomic files from CDROM 18 into 534910 line files GFALL.DAT and GFELEM.DAT. These are the data we actually use to compute spectra. They are not up to date. References are given in GFALL.REF or GFELEN.REF. There are no references after 1988. For light elements there are no references after 1979. We have the literature into the 1990's but have not had manpower or funding to update everything. Our current plan is to make a new semiempirical calculation for each species and at that time to include all the data from the literature. One new development is the inclusion of hyperfine splitting for the iron group elements using hyperfine data from the literature through 1993. The data are very incomplete. We have not yet included data for isotopic splitting. We supply a program for splitting the line list for a species. It reads the hyperfine and isotopic splitting parameters for levels and computes the oplittings whenever those levels appear. Lines with no splitting data are copied untouched. Because Sc, Mn, and Co are monoisotopic, only the hyperfine splittings are needed. Since 51V is much more abundant than S0V, the isotope shifts are small for 51V, and we approximate V with 51V. GFALLKYP.DAT has 754946 lines including hyperfine Sc(I), V(I), Mn(I), and Co(I). A bibliography for last year (1994-1995) is also attached.

98. DAM ROLLER GATE GENERAL ARRANGEMENTSECTION AND ELEVATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. DAM - ROLLER GATE - GENERAL ARRANGEMENT-SECTION AND ELEVATION (ML-8-47/1-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

Automation of the in vitro micronucleus and chromosome aberration assay for the assessment of the genotoxicity of the particulate and gas-vapor phase of cigarette smoke.

PubMed

Roemer, Ewald; Zenzen, Volker; Conroy, Lynda L; Luedemann, Kathrin; Dempsey, Ruth; Schunck, Christian; Sticken, Edgar Trelles

2015-01-01

Total particulate matter (TPM) and the gas-vapor phase (GVP) of mainstream smoke from the Reference Cigarette 3R4F were assayed in the cytokinesis-block in vitro micronucleus (MN) assay and the in vitro chromosome aberration (CA) assay, both using V79-4 Chinese hamster lung fibroblasts exposed for up to 24 h. The Metafer image analysis platform was adapted resulting in a fully automated evaluation system of the MN assay for the detection, identification and reporting of cells with micronuclei together with the determination of the cytokinesis-block proliferation index (CBPI) to quantify the treatment-related cytotoxicity. In the CA assay, the same platform was used to identify, map and retrieve metaphases for a subsequent CA evaluation by a trained evaluator. In both the assays, TPM and GVP provoked a significant genotoxic effect: up to 6-fold more micronucleated target cells than in the negative control and up to 10-fold increases in aberrant metaphases. Data variability was lower in the automated version of the MN assay than in the non-automated. It can be estimated that two test substances that differ in their genotoxicity by approximately 30% can statistically be distinguished in the automated MN and CA assays. Time savings, based on man hours, due to the automation were approximately 70% in the MN and 25% in the CA assays. The turn-around time of the evaluation phase could be shortened by 35 and 50%, respectively. Although only cigarette smoke-derived test material has been applied, the technical improvements should be of value for other test substances.

Light in the darkening on Naica gypsum crystals

NASA Astrophysics Data System (ADS)

Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Fuentes-Montero, M. E.; Esparza-Ponce, H. E.; Carreno-Márquez, J.; Reyes-Cortes, M.; Montero-Cabrera, M. E.

2015-07-01

Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performed at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe2O3), β-MnO2, Mn2O3, MnO and/or MnCO3, PbS, PbCO3 and/or PbSO4, ZnO4, ZnS and/or smithsonite (ZnCO3), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases.

Watershed-scale assessment of background concentrations and guidance values for heavy metals in soils from a semiarid and coastal zone of Brazil.

PubMed

da Silva, Yuri Jacques Agra Bezerra; do Nascimento, Clístenes Williams Araújo; Cantalice, José Ramon Barros; da Silva, Ygor Jacques Agra Bezerra; Cruz, Cinthia Maria Cordeiro Atanázio

2015-09-01

Determining heavy metal background concentrations in soils is fundamental in order to support the monitoring of potentially contaminated areas. This is particularly important to areas submitted to high environmental impact where an intensive and local monitoring is required. To this end, the aim of this study was to establish background concentrations and quality reference values (QRVs) for the heavy metals Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, As, and Hg in an environmentally impacted watershed from Brazil. Geochemical associations among Fe, Mn, and trace elements were also assessed to provide an alternative tool for establishing background concentrations. A total of one hundred and four samples comprised twenty-six composite soil samples from areas of native forest or minimal anthropic influence. Samples were digested (USEPA method 3051A), and the metals were determined by ICP-OES, except for As and Hg measured by atomic absorption spectrophotometer. Background concentrations of heavy metals in soils had the following decreasing order: Fe > Mn > Zn > Cr > Pb > Ni > Cu > As > Cd > Hg. These values were usually lower than those observed in the international and national literature. The QRVs for Ipojuca watershed followed the order (mg kg(-1)) Fe (13,020.40) > Mn (91.80) > Zn (30.12) > Cr (15.00) > Pb (13.12) > Cu (3.53) > Ni (3.30) > As (0.51) > Cd (0.08) > Hg (0.04). Significant correlation among Fe, Mn, and heavy metals shows that solubilization by the method 3051A provides a reasonable estimate for predicting background concentrations for Cd, Cr, and Cu as well as Zn, Cr, Cu, and Ni.

Multivariate analysis of selected metals in tannery effluents and related soil.

PubMed

Tariq, Saadia R; Shah, Munir H; Shaheen, N; Khalique, A; Manzoor, S; Jaffar, M

2005-06-30

Effluent and relevant soil samples from 38 tanning units housed in Kasur, Pakistan, were obtained for metal analysis by flame atomic absorption spectrophotometric method. The levels of 12 metals, Na, Ca, K, Mg, Fe, Mn, Cr, Co, Cd, Ni, Pb and Zn were determined in the two media. The data were evaluated towards metal distribution and metal-to-metal correlations. The study evidenced enhanced levels of Cr (391, 16.7 mg/L) and Na (25,519, 9369 mg/L) in tannery effluents and relevant soil samples, respectively. The effluent versus soil trace metal content relationship confirmed that the effluent Cr was strongly correlated with soil Cr. For metal source identification the techniques of principal component analysis, and cluster analysis were applied. The principal component analysis yielded two factors for effluents: factor 1 (49.6% variance) showed significant loading for Ca, Fe, Mn, Cr, Cd, Ni, Pb and Zn, referring to a tanning related source for these metals, and factor 2 (12.6% variance) with higher loadings of Na, K, Mg and Co, was associated with the processes during the skin/hide treatment. Similarly, two factors with a cumulative variance of 34.8% were obtained for soil samples: factor 1 manifested the contribution from Mg, Mn, Co, Cd, Ni and Pb, which though soil-based is basically effluent-derived, while factor 2 was found associated with Na, K, Ca, Cr and Zn which referred to a tannery-based source. The dendograms obtained from cluster analysis, also support the observed results. The study exhibits a gross pollution of soils with Cr at levels far exceeding the stipulated safe limit laid down for tannery effluents.

Determining the effectiveness of various treatment modalities in carpal tunnel syndrome by ultrasonography and comparing ultrasonographic findings with other outcomes.

PubMed

Soyupek, Feray; Yesildag, Ahmet; Kutluhan, Suleyman; Askin, Ayhan; Ozden, Ahmet; Uslusoy, Gokcen Ay; Demirci, Seden

2012-10-01

Firstly, we aimed to determine the effectiveness of various treatment modalities using ultrasonography (US), and secondly, we aimed to assess the correlations between the ultrasonographic findings and electrophysiological tests, symptom severity, functional status and physical findings. 74 hands of 47 patients with carpal tunnel syndrome (CTS) were randomly treated by applying wrist splinting alone in the neutral position (23 hands), phonophoresis with corticosteroid (PCS) (28 hands) and phonophoresis with non-steroid anti-inflamatory drug (PNSAI) (23 hands). The cross-sectional area (CSA) of the median nerve (MN) was determined by ultrasound on the initial and at the 3 months after treatment. MN conduction studies were performed on the initial visit and 3 months after treatment. The patients completed the Boston symptom severity questionnaire. For clinical evaluation, we used Phalen's and Tinel's signs. We could find reduction in CSA of MN in PCS group (P < 0.001). The CSA of MN was inversely correlated with motor sensory and median nerve conduction velocity (NCV) (r = 0.421, r = 0.213, respectively). Statistically significant correlations were not detected between ultrasonographic parameters and clinical evaluation parameters (P > 0.05) and also between ultrasonographic parameters and BQ scores (P > 0.05). Although there was some improvement in clinical parameters, ultrasonographic parameters did not change in P-NSAI group. The most effective treatment modality was P-CS according to ultrasonographic and other findings. Although there were inverse correlations between the CSA of MN and sensory and motor MN conduction velocity, no relationship was found between symptom severity, functional status and US findings or electrophysiological studies.

Environmental Exposure to Manganese in Air: Associations ...

EPA Pesticide Factsheets

Manganese (Mn), an essential element, can be neurotoxic in high doses. This cross-sectional study explored the oognitive function of adults residing in two towns (Marietta and East Liverpool, Ohio, USA) identified as having high levels of environmental airborne Mn from industrial sources. Air-Mn site surface emissions method modeling for total suspended particulate (TSP) ranged from 0.03 to 1.61 µg/m(3) in Marietta and 0.01-6.32 µg/m(3) in East Liverpool. A comprehensive screening test battery of cognitive function, including the domains of abstract thinking, attention/concentration, executive function and memory was administered. The mean age of the participants was 56 years (±10.8 years). Participants were mostly female (59.1) and primarily white (94.6%). Significant relationships (p<0.05) were found between Mn exposure and performance on working and visuospatial memory (e.g., Rey-0 Immediate B3=0.19, Rey-0 Delayed B3=0.16) and verbal skills (e.g., Similarities B3=0.19). Using extensive cognitive testing and computer modeling of 10-plus years of measured air monitoring data, this study suggests that long-term environmental exposure to high levels of air-Mn, the exposure metric of this paper, may result in mild deficits of cognitive function in adult populations. This study addresses research questions under Sustainable and Healthy Communities (2.2.1.6 lessons learned, best practices and stakeholder feedback from community and tribal participa

Metal contamination of home garden soils and cultivated vegetables in the province of Brescia, Italy: implications for human exposure.

PubMed

Ferri, Roberta; Hashim, Dana; Smith, Donald R; Guazzetti, Stefano; Donna, Filippo; Ferretti, Enrica; Curatolo, Michele; Moneta, Caterina; Beone, Gian Maria; Lucchini, Roberto G

2015-06-15

For the past century, ferroalloy industries in Brescia province, Italy produced particulate emissions enriched in manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), chromium (Cr), iron (Fe), and aluminum (Al). This study assessed metal concentrations in soil and vegetables of regions with varying ferroalloy industrial activity levels. Home gardens (n=63) were selected in three regions of varying ferroalloy plant activity durations in Brescia province. Total soil metal concentration and extractability were measured by X-Ray Fluorescence (XRF), aqua regia extraction, and modified Community Bureau of Reference (BCR) sequential extraction. Unwashed and washed spinach and turnips cultivated in the same gardens were analyzed for metal concentrations by flame atomic absorption spectrometry. Median soil Al, Cd, Fe, Mn, Pb, and Zn concentrations were significantly higher in home gardens near ferroalloy plants compared to reference home gardens. The BCR method yielded the most mobile soil fraction (the sum of extractable metals in Fractions 1 and 2) and all metal concentrations were higher in ferroalloy plant areas. Unwashed spinach showed higher metal concentrations compared to washed spinach. However, some metals in washed spinach were higher in the reference area likely due to history of agricultural product use. Over 60% of spinach samples exceeded the 2- to 4-fold Commission of European Communities and Codex Alimentarius Commission maximum Pb concentrations, and 10% of the same spinach samples exceeded 2- to 3-fold maximum Cd concentrations set by both organizations. Turnip metal concentrations were below maximum standard reference values. Prolonged industrial emissions increase median metal concentrations and most soluble fractions (BCR F1+F2) in home garden soils near ferroalloy plants. Areas near ferroalloy plant sites had spinach Cd and Pb metal concentrations several-fold above maximum standard references. We recommend thorough washing of vegetables to minimize metal exposure. Copyright © 2015 Elsevier B.V. All rights reserved.

Metal contamination of home gardens soils and cultivated vegetables in the province of Brescia, Italy: Implications for human exposure

PubMed Central

Ferri, Roberta; Hashim, Dana; Smith, Donald R.; Guazzetti, Stefano; Donna, Filippo; Ferretti, Enrica; Curatolo, Michele; Moneta, Caterina; Beone, Gian Maria; Lucchini, Roberto G.

2015-01-01

Background For the past century, ferroalloy industries in Brescia province, Italy produced particulate emissions enriched in manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), chromium (Cr), iron (Fe), aluminum (Al). This study assessed metal concentrations in soil and vegetables of regions with varying ferroalloy industrial activity levels. Methods Home gardens (n=63) were selected in three regions of varying ferroalloy plant activity duration in Brescia province. Total soil metal concentration and extractability were measured by X-ray fluorescence (XRF), aqua regia extraction, and modified Community Bureau of Reference (BCR) sequential extraction. Unwashed and washed spinach and turnips cultivated in the same gardens were analyzed for metal concentrations by flame atomic absorption spectrometry. Results Median soil Al, Cd, Fe, Mn, Pb, and Zn concentrations were significantly higher in home gardens near ferroalloy plants compared to reference home gardens. The BCR method yielded the most mobile soil fraction (the sum of extractable metals in Fractions 1 and 2) and all metal concentrations were higher in ferroalloy plant areas. Unwashed spinach showed higher metal concentrations compared to washed spinach. However, some metals in washed spinach were higher in the reference area likely due to history of agricultural product use. Over 60% of spinach samples exceeded the 2- to 4-fold Commission of European Communities and Codex Alimentarius Commission maximum Pb concentrations, and 10% of the same spinach samples exceeded 2- to 3-fold maximum Cd concentrations set by both organizations. Turnip metal concentrations were below maximum standard reference values. Conclusions Prolonged industrial emissions increase median metal concentrations and most soluble fractions (BCR F1+F2) in home garden soils near ferroalloy plants. Areas near ferroalloy plant sites had spinach Cd and Pb metal concentrations several-fold above maximum standard references. We recommend thoroughly washing vegetables to minimize metal exposure. PMID:25777956

Microbially-induced Fe and Mn oxides in condensed pelagic sediments (Middle-Upper Jurassic, Western Sicily)

NASA Astrophysics Data System (ADS)

Préat, A.; Mamet, B.; Di Stefano, P.; Martire, L.; Kolo, K.

2011-06-01

This article presents a petrographic comparison of the Rosso Ammonitico facies of Western Sicily and the original Rosso Ammonitico Veronese of Northern Italy based on a total of 27 sections. The Rosso Ammonitico has been the subject of numerous controversies that range from bathyal to shallow-water platform sedimentation. Therefore it seemed interesting to verify if the term Rosso Ammonitico has the same geologic connotation from region to region. The Middle-Upper Jurassic Rosso Ammonitico of Western Sicily is a condensed succession formed during a period of extensional synsedimentary tectonics related to the spreading of the Ionian Ocean. Slope-to-basin or pelagic carbonate deposits characterize the sedimentation which consists of reddish mudstones and wackestones. The abundant fauna is composed of radiolarians, protoglobigerinids, Saccocoma, Bositra associated with ammonites. A few ferruginous hardgrounds, Fe-Mn oxide crusts and Mn-coated condensation horizons are also present. The red matrices contain abundant Fe-Mn encrusted, microbored and bioeroded bioclasts. Sporadic Fe-Mn oncolites composed of amorphous Mn-minerals and goethite are also conspicuous. The matrix, as well as the shells and the fillings of the complex associated veinlets, are frequently altered into calcite microsparite. Submicronic iron bacterial and fungal filaments associated with mineralized extracellular polymeric substances (EPS) are observed in the matrix. They record dysaerobic microenvironments at or near the sediment-water interfaces. Early mineralized discontinuities enhanced by subsequent pressure dissolution are reported in the succession. Mn-(Ni) bacterial filaments are exceptionally observed in the cortex of the Fe-Mn oncolites. As a consequence of an early lithification, the Mn filaments are poorly preserved. The pigmentation of the rock is due to the dispersion of submicronic oxyhydroxides (now goethite and amorphous iron) formed by bacterial mediation during early diagenesis in microaerophilitic environments. As in the case of the original 'Rosso Ammonitico Veronese', Fe and Mn bacteria/fungi were able to produce bioconstructions which have no bathymetric significance. The limiting factor must have been the oxygen content which was low in these very quiet and relatively deep environments. Thus the Rosso Ammonitico of northern and southern Italy have a number of points in common, but some obvious dissimilarities are observed that explain some of the various sedimentological interpretations. Among them, the chemical composition is of particular importance, more Fe is present in Veneto (Northern Italy) while Mn is associated with the Sicilian Rosso Ammonitico. The Sicilian localities were more proximal to oceanic magmatic sources which were related to the activity of the oceanic crust.

Ground penetrating radar survey of pavement thickness on Mn/Road sections : final report

DOT National Transportation Integrated Search

1994-11-01

The research shows that highway speed horn antenna ground penetrating radar equipment and automated analysis software can accurately measure asphalt thickness. To accurately measure concrete and base thickness, lower speed ground coupled equipment al...

76 FR 49527 - Supplemental Environmental Impact Statement; Cottonwood and Watonwan Counties, Minnesota

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-10

... three sections of Trunk Highway (TH) 60. FOR FURTHER INFORMATION CONTACT: Philip Forst, Environmental... TH 60 from Worthington to St. James in 1983 (FHWA-MN-EIS-82-02-F). A Record of Decision (ROD) was...

48. East tile gauge on south pier. Each square tile ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

48. East tile gauge on south pier. Each square tile is 4' in size. Lower section of tile cross only - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

Electron propagator calculations on the ionization energies of CrH -, MnH - and FeH -

NASA Astrophysics Data System (ADS)

Lin, Jyh-Shing; Ortiz, J. V.

1990-08-01

Electron propagator calculations with unrestricted Hartree-Fock reference states yield the ionization energies of the title anions. Spin contamination in the anionic reference state is small, enabling the use of second-and third-order self-energies in the Dyson equation. Feynman-Dyson amplitudes for these ionizations are essentially identical to canonical spin-orbitals. For most of the final states, these consist of an antibonding combination of an sp metal hybrid, polarized away from the hydrogen, and hydroegen s functions. In one case, the Feynman-Dyson amplitude consists of nonbonding d functions. Calculated ionization energies are within 0.5 eV of experiment.

Energy dispersive X-ray fluorescence (EDXRF) equipment calibration for multielement analysis of soil and rock samples

NASA Astrophysics Data System (ADS)

de Moraes, Alex Silva; Tech, Lohane; Melquíades, Fábio Luiz; Bastos, Rodrigo Oliveira

2014-11-01

Considering the importance to understand the behavior of the elements on different natural and/or anthropic processes, this study had as objective to verify the accuracy of a multielement analysis method for rocks characterization by using soil standards as calibration reference. An EDXRF equipment was used. The analyses were made on samples doped with known concentration of Mn, Zn, Rb, Sr and Zr, for the obtainment of the calibration curves, and on a certified rock sample to check the accuracy of the analytical curves. Then, a set of rock samples from Rio Bonito, located in Figueira city, Paraná State, Brazil, were analyzed. The concentration values obtained, in ppm, for Mn, Rb, Sr and Zr varied, respectively, from 175 to 1084, 7.4 to 268, 28 to 2247 and 15 to 761.

The origin and evolution of the odd-Z iron-peak elements Sc, V, Mn, and Co in the Milky Way stellar disk

NASA Astrophysics Data System (ADS)

Battistini, Chiara; Bensby, Thomas

2015-05-01

Context. Elements heavier than Li are produced in the interiors of stars. However, for many elements the exact production sites and the timescales on which they are dispersed into the interstellar medium are unknown. Having a clear picture on the origins of the elements is important for our ability to trace and understand the formation and chemical evolution of the Milky Way and its stellar populations. Aims: The aim of this study is to investigate the origin and evolution of Sc, V, Mn, and Co for a homogeneous and statistically significant sample of stars probing the different populations of the Milky Way, in particular the thin and thick disks. Methods: Using high-resolution spectra obtained with the MIKE, FEROS, SOFIN, FIES, UVES, and HARPS spectrographs, we determine Sc, V, Mn, and Co abundances for a large sample of F and G dwarfs in the solar neighborhood. The method is based on spectral synthesis and using one-dimensional, plane-parallel, local thermodynamic equilibrium (LTE) model stellar atmospheres calculated with the MARCS 2012 code. The non-LTE (NLTE) corrections from the literature were applied to Mn and Co. Results: We find that the abundance trends derived for Sc (594 stars), V (466 stars), and Co (567 stars) are very similar to what has been observed for the α-elements in the thin and thick disks. On the contrary, Mn (569 stars) is generally underabundant relative to the Sun (i.e., [ Mn/Fe ] < 0) for [ Fe/H ] < 0. In addition, for Mn, when NLTE corrections are applied, the trend changes and is almost flat over the entire metallicity range of the stars in our sample (-2 ≲ [ Fe/H ] ≲ + 0.4). The [Sc/Fe]-[Fe/H] abundance trends show a small separation between the thin and thick disks, while for V and Co they completely overlap. For Mn there is a small difference in [Mn/Fe], but only when NLTE corrections are used. Comparisons with Ti as a reference element show flat trends for all the elements except for Mn that show well separated [Mn/Ti]-[Ti/H] trends for the thin and thick disks. Conclusions: The elements Sc and V present trends compatible with production from type II supernovae (SNII) events. In addition, Sc clearly shows a metallicity dependence for [ Fe/H ] < -1. Instead, Mn is produced in SNII events for [ Fe/H ] ≲ -0.4 and then type Ia supernovae start to produce Mn. Finally, Co appears to be produced mainly in SNII with suggestion of enrichment from hypernovae at low metallicities. This paper includes data gathered with the 6.5 m Magellan Telescopes located at the Las Campanas Observatory, Chile; the Nordic Optical Telescope (NOT) on La Palma, Spain; the Very Large Telescope (VLT) at the European Southern Observatory (ESO) on Paranal, Chile (ESO Proposal ID 69.B-0277 and 72.B-0179); the ESO 1.5-m, 2.2-m. and 3.6-m telescopes on La Silla, Chile (ESO Proposal ID 65.L-0019, 67.B-0108, 76.B-0416, 82.B-0610); and data from UVES Paranal Observatory Project (ESO DDT Program ID 266.D-5655).Full versions of Tables 2 and 5 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/577/A9Appendices are available in electronic form at http://www.aanda.org

Synthesis of a highly efficient 3D graphene-CNT-MnO2-PANI nanocomposite as a binder free electrode material for supercapacitors.

PubMed

Asif, Muhammad; Tan, Yi; Pan, Lujun; Rashad, Muhammad; Li, Jiayan; Fu, Xin; Cui, Ruixue

2016-09-29

Graphene based nanocomposites have been investigated intensively, as electrode materials for energy storage applications. In the current work, a graphene-CNT-MnO 2 -PANI (GCM@PANI) nanocomposite has been synthesized on 3D graphene grown on nickel foam, as a highly efficient binder free electrode material for supercapacitors. Interestingly, the specific capacitance of the synthesized electrode increases up to the first 1500 charge-discharge cycles, and is thus referred to as an electrode activation process. The activated GCM@PANI nanocomposite electrode exhibits an extraordinary galvanostatic specific capacitance of 3037 F g -1 at a current density of 8 A g -1 . The synthesized nanocomposite exhibits an excellent cyclic stability with a capacitance retention of 83% over 12 000 charge-discharge cycles, and a high rate capability by retaining a specific capacitance of 84.6% at a current density of 20 A g -1 . The structural and electrochemical analysis of the synthesized nanocomposite suggests that the astonishing electrochemical performance might be attributed to the growth of a novel PANI nanoparticle layer and the synergistic effect of CNT/MnO 2 nanostructures.

Electronic structure and spectroscopic properties of mononuclear manganese(III) Schiff base complexes: a systematic study on [Mn(acen)X] complexes by EPR, UV/vis, and MCD spectroscopy (X = Hal, NCS).

PubMed

Westphal, Anne; Klinkebiel, Arne; Berends, Hans-Martin; Broda, Henning; Kurz, Philipp; Tuczek, Felix

2013-03-04

The manganese(III) Schiff base complexes [Mn(acen)X] (H2acen: N,N'-ethylenebis(acetylacetone)imine, X: I(-), Br(-), Cl(-), NCS(-)) are considered as model systems for a combined study of the electronic structure using vibrational, UV/vis absorption, parallel-mode electron paramagnetic resonance (EPR) and low-temperature magnetic circular dichroism (MCD) spectroscopy. By variation of the co-ligand X, the influence of the axial ligand field within a given square-pyramidal coordination geometry on the UV/vis, EPR, and MCD spectra of the title compounds is investigated. Between 25000 and 35000 cm(-1), the low-temperature MCD spectra are dominated by two very intense, oppositely signed pseudo-A terms, referred to as "double pseudo-A terms", which change their signs within the [Mn(acen)X] series dependent on the axial ligand X. Based on molecular orbital (MO) and symmetry considerations, these features are assigned to π(n.b.)(s, a) → yz, z(2) ligand-to-metal charge transfer transitions. The individual MCD signs are directly determined from the calculated MOs of the [Mn(acen)X] complexes. The observed sign change is explained by an inversion of symmetry among the π(n.b.)(s, a) donor orbitals which leads to an interchange of the positive and negative pseudo-A terms constituting the "double pseudo-A term".

Synthesis, spectroscopic characterization, first order nonlinear optical properties and DFT calculations of novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 1,3-diphenyl-4-phenylazo-5-pyrazolone ligand

NASA Astrophysics Data System (ADS)

Abdel-Latif, Samir A.; Mohamed, Adel A.

2018-02-01

Novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions with 1,3-diphenyl-4-phenylazo-5-pyrazolone (L) have been prepared and characterized using different analytical and spectroscopic techniques. 1:1 Complexes of Mn(II), Co(II) and Zn(II) are distorted octahedral whereas Ni(II) complex is square planar and Cu(II) is distorted trigonal bipyramid. 1:2 Complexes of Mn(II), Co(II), Cu(II) and Zn(II) are distorted trigonal bipyramid whereas Ni(II) complex is distorted tetrahedral. All complexes behave as non-ionic in dimethyl formamide (DMF). The electronic structure and nonlinear optical parameters (NLO) of the complexes were investigated theoretically at the B3LYP/GEN level of theory. Molecular stability and bond strengths have been investigated by applying natural bond orbital (NBO) analysis. The geometries of the studied complexes are non-planner. DFT calculations have been also carried out to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The calculated small energy gap between HOMO and LUMO energies shows that the charge transfer occurs within the complexes. The total static dipole moment (μtot), the mean polarizability (<α>), the anisotropy of the polarizability (Δα) and the mean first-order hyperpolarizability (<β>) were calculated and compared with urea as a reference material. The complexes show implying optical properties.

Manganese-oxidizing photosynthesis before the rise of cyanobacteria

NASA Astrophysics Data System (ADS)

Johnson, J. E.; Webb, S.; Thomas, K. S.; Ono, S.; Kirschvink, J. L.; Fischer, W. W.

2012-12-01

The evolution of oxygenic photosynthesis was a singularity that fundamentally transformed our planet's core biogeochemical cycles and changed the redox structure of Earth's surface, crust, and mantle. To date, understanding the evolution of this molecular machinery has largely been derived from comparative biology. Several biochemical innovations enabled water-splitting, including a central photosynthetic pigment with a higher redox potential and coupled photosystems. However the critical photochemical invention was the water oxidizing complex (WOC) of photosystem II, a cubane cluster of four redox-active Mn atoms and a Ca atom bound by oxo bridges, that couple the single electron photochemistry of the photosystem to the four-electron oxidation of water to O2. Transitional forms of the WOC have been postulated, including an Mn-containing catalase-like peptide using an H2O2 donor, or uptake and integration of environmental Mn-oxides. One attractive hypothesis from the perspective of modern photo-assembly of the WOC posits an initial Mn(II)-oxidizing photosystem as a precursor to the WOC (Zubay, 1996; Allen and Martin, 2007). To test these hypotheses, we studied the behavior of the ancient Mn cycle captured by 2415 ± 6 Ma scientific drill cores retrieved by the Agouron Drilling Project through the Koegas Subgroup in Griqualand West, South Africa. This succession contains substantial Mn-enrichments (up to 17 wt.% in bulk). To better understand the petrogenesis and textural context of these deposits, we employed a novel X-ray absorption spectroscopy microprobe to make redox maps of ultra-thin sample sections at a 2μm scale. Coupled to light and electron microscopy and C isotopic measurements, we observe that all of the Mn is present as Mn(II), contained within carbonate minerals produced from early diagenetic reduction of Mn-oxide phases with organic matter. To assay the environmental oxidant responsible for the production of the Mn-oxides we examined two independent techniques sensitive to low levels of environmental O2—multiple sulfur isotopes analyzed using whole-rock IRMS and texture-specific SIMS techniques, and the presence of redox-sensitive detrital grains. Despite the conspicuous oxidation of Mn, both proxies reveal a lack of significant molecular oxygen present in the environment at this time (O2 << 1 ppm). These results provide strong geological support for the idea that an early Mn-oxidizing photosystem once existed as a transitional form prior to the evolution of the WOC of photosystem II and oxygenic photosynthesis. [Refs: Zubay J (1996) Origins of Life on the Earth and in the Cosmos, Academic Press: San Diego. Allen JF, Martin W (2007) Evolutionary biology: Out of thin air, Nature, 445, 610-612.

Photographic copy of architectural drawing, 1921 (original located at University ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of architectural drawing, 1921 (original located at University of Minnesota Facilities Management Office, Minneapolis). BIN TOWER SECTIONS AND PLAN - Mines Experiment Station, University of Minnesota, Twin Cities Campus, 56 East River Road, Minneapolis, Hennepin County, MN

Photographic copy of architectural drawing, 1921 (original located at University ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of architectural drawing, 1921 (original located at University of Minnesota Facilities Management Office, Minneapolis). SOUTH ELEVATION, TRANSVERSE SECTION, NORTH ELEVATION - Mines Experiment Station, University of Minnesota, Twin Cities Campus, 56 East River Road, Minneapolis, Hennepin County, MN

43. East tile gauge on south pier. Each square tile ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

43. East tile gauge on south pier. Each square tile is 4' in size. Eagle itself in 4' square eagle section - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

Optical anisotropy and domain structure of multiferroic Ni-Mn-Ga and Co-Ni-Ga Heusler-type alloys

NASA Astrophysics Data System (ADS)

Ivanova, A. I.; Gasanov, O. V.; Kaplunova, E. I.; Kalimullina, E. T.; Zalyotov, A. B.; Grechishkin, R. M.

2015-03-01

A study is made of the reflectance anisotropy of martensitic and magnetic domains in ferromagnetic shape memory alloys (FSMA) Ni-Mn-Ga and Co-Ni-Ga. The reflectance of metallographic sections of these alloys was measured in the visible with the aid of standard inverted polarized light microscope with a 360° rotatable specimen stage. Calculations are presented for the estimation of image contrast values between neighboring martensite twins. Qualitative and quantitative observations and angular measurements in reflected polarized light proved to be useful for the analysis of specific features of the martensite microstructure of multiferroic materials.

Reference Values of 14 Serum Trace Elements for Pregnant Chinese Women: A Cross-Sectional Study in the China Nutrition and Health Survey 2010–2012

PubMed Central

Liu, Xiaobing; Zhang, Yu; Piao, Jianhua; Mao, Deqian; Li, Yajie; Li, Weidong; Yang, Lichen; Yang, Xiaoguang

2017-01-01

The development of reference values of trace elements is recognized as a fundamental prerequisite for the assessment of trace element nutritional status and health risks. In this study, a total of 1400 pregnant women aged 27.0 ± 4.5 years were randomly selected from the China Nutrition and Health Survey 2010–2012 (CNHS 2010–2012). The concentrations of 14 serum trace elements were determined by high-resolution inductively coupled plasma mass spectrometry. Reference values were calculated covering the central 95% reference intervals (P2.5–P97.5) after excluding outliers by Dixon’s test. The overall reference values of serum trace elements were 131.5 (55.8-265.0 μg/dL for iron (Fe), 195.5 (107.0–362.4) μg/dL for copper (Cu), 74.0 (51.8–111.3) μg/dL for zinc (Zn), 22.3 (14.0–62.0) μg/dL for rubidium (Rb), 72.2 (39.9–111.6) μg/L for selenium (Se), 45.9 (23.8-104.3) μg/L for strontium (Sr), 1.8 (1.2–3.6) μg/L for molybdenum (Mo), 2.4 (1.2–8.4) μg/L for manganese (Mn), 1.9 (0.6–9.0) ng/L for lead (Pb), 1.1 (0.3-5.6) ng/L for arsenic (As), 835.6 (219.8–4287.7) ng/L for chromium (Cr), 337.9 (57.0–1130.0) ng/L for cobalt (Co), 193.2 (23.6–2323.1) ng/L for vanadium (V), and 133.7 (72.1–595.1) ng/L for cadmium (Cd). Furthermore, some significant differences in serum trace element reference values were observed between different groupings of age intervals, residences, anthropometric status, and duration of pregnancy. We found that serum Fe, Zn, and Se concentrations significantly decreased, whereas serum Cu, Sr, and Co concentrations elevated progressively compared with reference values of 14 serum trace elements in pregnant Chinese women. The reference values of serum trace elements established could play a key role in the following nutritional status and health risk assessment. PMID:28335545

Characterization and differentiation of rock varnish types from different environments by microanalytical techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macholdt, D. S.; Jochum, K. P.; Pöhlker, C.

We investigated rock varnishes collected from several locations and environments worldwide by a wide range of microanalytical techniques. These techniques were selected to address the challenges posed by the chemical and structural complexity within the micrometer- to nanometer-sized structures in these geological materials. Femtosecond laser ablation-inductively coupled plasma-mass spectrometry (fs LA-ICP-MS), scanning transmission X-ray microscopy-near edge X-ray adsorption fine structure spectroscopy (STXM-NEXAFS) in combination with scanning electron microscopy (SEM) of focused ion beam (FIB) ultra-thin (100–200 nm) sections, conventional and polarization microscopy, as well as electron paramagnetic resonance (EPR) measurements were used to obtain information about these rock varnishes. Rockmore » varnishes from different environments, which cannot readily be distinguished based on their macroscopic appearance, differ significantly in their constituent elemental mass fractions, e.g., of Mn, Fe, Ni, Co, Ba, and Pb, and their rare earth element (REE) patterns. Structural characteristics such as the particle sizes of embedded dust grains, internal structures such as layers of Mn-, Fe-, and Ca -rich material, and structures such as cavities varied between varnishes from different environments and regions in the world. The EPR spectra were consistent with aged biogenic Mn oxides in all samples, but showed subtle differences between samples of different origin. Our observations allow us to separate rock varnishes into different types, with differences that might be indicators of distinct geneses. Five different types of rock varnish could be distinguished, Type I–V, of which only Type I might be used as potential paleoclimate archive. Each varnish type has specific characteristics in terms of their elemental composition, element distribution, and structures. The combination of element ratios (Mn/Ba, Al/Ni, Mn/REY, Mn/Ce, Mn/Pb, La N /Yb N , and Ce/Ce*), total REE contents, and structures can be used to separate the different types of rock varnish from each other.« less

31 CFR 598.401 - Reference to amended sections.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Reference to amended sections. 598.401 Section 598.401 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Interpretations § 598.401 Reference to amended sections. Except as otherwise specified, reference...

Nickel and cobalt distribution in the laterites of the Lomié region, south-east Cameroon

NASA Astrophysics Data System (ADS)

Yongue-Fouateu, R.; Ghogomu, R. T.; Penaye, J.; Ekodeck, G. E.; Stendal, H.; Colin, F.

2006-05-01

In the Lomié region (south-east Cameroon), strong weathering of serpentinized ultramafic rocks has produced a thick laterite cover with significant nickel and cobalt contents. The highest concentrations of these elements are located in the middle section of the laterite profiles, in the lower clay horizon, and preferentially along the slopes of the interfluves. The investigation of the composition of the laterite ores (by whole-rock analysis) and of the main components, using SEM/microprobe and XRD, reveals the presence of four main enriched facies: a non-differentiated facies, a layered smectitic facies, a quartz-rich facies and a gibbsitic nodular facies. Nickel, with generally low concentrations (less than 2% NiO), is hosted by several secondary mineral phases (goethite, Mn-oxyhydroxides and smectite locally). Cobalt is generally of higher grade (up to 0.9% CoO), and is associated with cryptocrystalline and crystallized Mn-oxyhydroxides. SEM/microprobe observations suggest that nickel and cobalt concentration in secondary minerals is due to repeated remobilization. This has also favored the formation of mineral phases, of which the best crystallized and most richly mineralized are mainly those of the asbolan-lithiophorite group. The SEM studies indicate that these mineral phases show various morphologies related to their chemical composition: poorly crystallized nipple shaped (Fe, Mn, Ni), fine cross-bedded needles (Mn, Ni) and elongated crystals (Mn, Al, Ni, Co) occur in the layered smectitic facies, while platy and needle-like forms (Mn, Al, Ni, Co) characterize the gibbsitic nodular facies. The predominantly cobaltiferous nature of the Lomié laterite ore deposit is the result of remobilizations and transformations of elements that led to the impoverishment of both the Ni-Co contents of the laterite but most importantly of Ni rather than Co.

Study design and statistical analysis of data in human population studies with the micronucleus assay.

PubMed

Ceppi, Marcello; Gallo, Fabio; Bonassi, Stefano

2011-01-01

The most common study design performed in population studies based on the micronucleus (MN) assay, is the cross-sectional study, which is largely performed to evaluate the DNA damaging effects of exposure to genotoxic agents in the workplace, in the environment, as well as from diet or lifestyle factors. Sample size is still a critical issue in the design of MN studies since most recent studies considering gene-environment interaction, often require a sample size of several hundred subjects, which is in many cases difficult to achieve. The control of confounding is another major threat to the validity of causal inference. The most popular confounders considered in population studies using MN are age, gender and smoking habit. Extensive attention is given to the assessment of effect modification, given the increasing inclusion of biomarkers of genetic susceptibility in the study design. Selected issues concerning the statistical treatment of data have been addressed in this mini-review, starting from data description, which is a critical step of statistical analysis, since it allows to detect possible errors in the dataset to be analysed and to check the validity of assumptions required for more complex analyses. Basic issues dealing with statistical analysis of biomarkers are extensively evaluated, including methods to explore the dose-response relationship among two continuous variables and inferential analysis. A critical approach to the use of parametric and non-parametric methods is presented, before addressing the issue of most suitable multivariate models to fit MN data. In the last decade, the quality of statistical analysis of MN data has certainly evolved, although even nowadays only a small number of studies apply the Poisson model, which is the most suitable method for the analysis of MN data.

Interference Method for Obtaining the Potential Flow Past an Arbitrary Cascade of Airfoils

DTIC Science & Technology

1947-05-01

1 ’ m2?mN copy.*”..... .#,. NATIONALADVISORYCOMMITTEE FORAERONAUTICS TECHNICALNOTE No. 1252 INTERFERENCE METHOD FOR OBTAI?N’ENGTHE POTENTIAL FLOW PAST...infinitelattices.Mostofthesestudiesinvolveapproximate procedures(foremmple,references 1 to 3) or presentsolutions forspecialclassesofshapes...ofinterferingbodies, . b u . NACATNNO,1252 v r. K v 7 m z Z* 1 t c c]. a ~ 0 s P u x * a ~ AP c) circtiation IBq@ng-fUnctilxl localvelocity

Factors Influencing Temperature Fields during Combustion Reactions

DTIC Science & Technology

2014-05-20

promoting thermal energy distributions. Keywords: Thermites · Nanoparticle combustion • Aluminum · Infrared thermometry • Non-ideal explosives 1...materials (nano- thermite ) comprised of a metallic fuel and organic or metal- lic oxidizer and will be referred to as nanothermites hence forth. The most...magnesium (Mg), manganese (Mn), and titanium (Ti) nanoparticles were added to Al/CuO at 10% by weight of the nanothermite sample. The nano- thermites with

Results of JAUS OPC Experiment 3.0

DTIC Science & Technology

2006-05-01

AFRL-ML-TY-TP-2006-4555 POSTPRINT RESULTS OF JAUS OPC EXPERIMENT 3.0 M.N. Clark Harris Corporation-GCSD Melbourne FL 32902-0037...permission to manufacture, use, or sell any patented invention that may relate to them. This technical report was reviewed and cleared for public...Service (NTIS). Reference PAO Case Number AFRL/MLQ-06-069. This report is releasable to the National Technical Information Service (NTIS) where

Synthesis and Electrochemical Performance of LixMn2-yCoyO4-dCld Cathode Material

DTIC Science & Technology

2016-06-13

Lithium manganese oxide spinel is a potential candidate for Li- ion battery cathodes because of its...240 mAh/g of active material, and 4) high rate charge and discharge. Keywords: Lithium and Li- ion battery , Lithium manganese oxide spinel, Spinel...demonstrate desirable traits for incorporation into lithium - ion batteries for the military. References 1. David Linden (Ed.); Handbook of Batteries

Petrography of isotopically-dated clasts in the Kapoeta howardite and petrologic constraints on the evolution of its parent body

NASA Technical Reports Server (NTRS)

Dymek, R. F.; Albee, A. L.; Chodos, A. A.; Wasserburg, G. J.

1976-01-01

Results are presented for petrographic and electron microprobe studies of the isotopically dated A, B, C, and rho basaltic rock fragments separated from the howardite Kapoeta. Other lithic clasts and numerous mineral fragments in thin sections of Kapoeta are investigated in order to outline the range in lithology and chemistry of the source materials from which the Kapoeta meteorite is derived. The data obtained are compared to those from other meteorite and lunar samples, with particular reference to the observational consequences for the evolution of the Kapoeta parent body. A major conclusion is that there is no clearcut evidence for young magmatism on the Kapoeta parent body. The observations preclude the interpretation that the Kapoeta is a simple mixture of eucrites and diogenites. In contrast to the moon, a source of anorthositic rocks does not appear to have been present on the Kapoeta parent body which involved chiefly pyroxene. The FeO-MnO relationships suggest that the source of the materials in the Kapoeta parent planet are fundamentally related.

23. Photographic copy of photograph (ca. 1930, photograph taken by ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. Photographic copy of photograph (ca. 1930, photograph taken by Harold Youngren; print located at Two Harbors Public Library, Two Harbors). "Machine shop and blacksmith shop." West end wall of boiler shop section of roundhouse also visible. Note monitors atop each section. View to northeast. - Duluth & Iron Range Rail Road Company Shops, Roundhouse, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

31 CFR 598.401 - Reference to amended sections.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Reference to amended sections. 598.401 Section 598.401 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 598.401 Reference to amended sections. Except as otherwise specified, reference to any provision...

31 CFR 598.401 - Reference to amended sections.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Reference to amended sections. 598.401 Section 598.401 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 598.401 Reference to amended sections. Except as otherwise specified, reference to any provision...

31 CFR 598.401 - Reference to amended sections.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Reference to amended sections. 598.401 Section 598.401 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 598.401 Reference to amended sections. Except as otherwise specified, reference to any provision...

31 CFR 598.401 - Reference to amended sections.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Reference to amended sections. 598.401 Section 598.401 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 598.401 Reference to amended sections. Except as otherwise specified, reference to any provision...

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands.

PubMed

Kubová, Jana; Matús, Peter; Bujdos, Marek; Hagarová, Ingrid; Medved', Ján

2008-05-30

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.

Concentrations of metals in blood and feathers of nestling ospreys (Pandion haliaetus) in Chesapeake and Delaware Bays

USGS Publications Warehouse

Rattner, B.A.; Golden, N.H.; Toschik, P.C.; McGowan, P.C.; Custer, T.W.

2008-01-01

In 2000, 2001, and 2002, blood and feather samples were collected from 40-45-day-old nestling ospreys (Pandion haliaetus) from Chesapeake Bay and Delaware Bay and River. Concentrations of 18 metals, metalloids, and other elements were determined in these samples by inductively coupled plasma-mass spectroscopy, and Hg concentrations were measured by cold vapor atomic absorption spectroscopy. When compared to concurrent reference areas (South, West, and Rhode Rivers), mean As and Hg concentrations in blood were greater (p < 0.05) in two of three Chesapeake Bay regions of concern (Baltimore Harbor [As: 1.18 vs. 0.548 mug/g dw], Anacostia River [Hg: 0.305 vs. 0.178 mug/g dw], and Elizabeth River [As: 0.876 vs. 0.663 mug/g dw; Hg: 0.260 vs. 0.180 mug/g dw]). Lead was detected more frequently in blood of nestlings from the highly industrialized Elizabeth River compared to the rural reference area. When compared to the concurrent reference area, mean Al, Ba, Hg, Mn, and Pb concentrations in feathers were substantially greater (p < 0.05) in one or more Chesapeake regions of concern (Anacostia River [Al: 206 vs. 62.1 mug/g dw; Ba: 3.31 vs. 0.823 mug/g dw; Mn: 65.4 vs. 22.9 mug/g dw] and Elizabeth River [Al: 165 vs. 63.5 mug/g dw; Hg: 1.24 vs. 0.599 mug/g dw; Pb 1.47 vs. 0.543 mug/g dw]). When compared to the coastal Inland Bays reference area, feathers of nestlings from northern Delaware Bay and River had greater concentrations (p < 0.05) of Ba (1.90 vs. 0.660 mug/g dw), Fe (258 vs. 109 mug/g dw), Mn (18.5 vs. 4.66 mug/g dw), Mo (0.130 vs. 0.040 mug/g dw), Pb (1.96 vs. 0.624 mug/g dw), and V (0.671 vs. 0.325 mug/g dw), presumably due to extensive metal-working and petroleum refinery activities. Concentrations of Hg in nestling feathers from Delaware were frequently greater than in the Chesapeake. The present findings and those of related reproductive studies suggest that concentrations of several heavy metals (e.g., Cd, Hg, Pb) in nestling blood and feathers from Chesapeake and Delaware Bays were below toxicity thresholds and do not seem to be affecting chick survival during the nestling period.

A look inside the nerve - Morphology of nerve fascicles in healthy controls and patients with polyneuropathy.

PubMed

Grimm, Alexander; Winter, Natalie; Rattay, Tim W; Härtig, Florian; Dammeier, Nele M; Auffenberg, Eva; Koch, Marilin; Axer, Hubertus

2017-12-01

Polyneuropathies are increasingly analyzed by ultrasound. Summarizing, diffuse enlargement is typical in Charcot-Marie Tooth type 1 (CMT1a), regional enlargement occurs in inflammatory neuropathies. However, a distinction of subtypes is still challenging. Therefore, this study focused on fascicle size and pattern in controls and distinct neuropathies. Cross-sectional area (CSA) of the median, ulnar and peroneal nerve (MN, UN, PN) was measured at predefined landmarks in 50 healthy controls, 15 CMT1a and 13 MMN patients. Additionally, largest fascicle size and number of visible fascicles was obtained at the mid-upper arm cross-section of the MN and UN and in the popliteal fossa cross-section of the PN. Cut-off normal values for fascicle size in the MN, UN and PN were defined (<4.8mm 2 , <2.8mm 2 and <3.5mm 2 ). In CMT1a CSA and fascicle values are significantly enlarged in all nerves, while in MMN CSA and fascicles are regionally enlarged with predominance in the upper arm nerves. The ratio of enlarged fascicles and all fascicles was significantly increased in CMT1a (>50%) in all nerves (p<0.0001), representing diffuse fascicle enlargement, and moderately increased in MMN (>20%), representing differential fascicle enlargement (enlarged and normal fascicles at the same location) sparing the peroneal nerve (regional fascicle enlargement). Based on these findings distinct fascicle patterns were defined. Normal values for fascicle size could be evaluated; while CMT1a features diffuse fascicle enlargement, MMN shows regional and differential predominance with enlarged fascicles as single pathology. Pattern analysis of fascicles might facilitate distinction of several otherwise similar neuropathies. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Development of a new magnetocaloric material used in a magnetic refrigeration device

NASA Astrophysics Data System (ADS)

Guillou, F.; Legait, U.; Kedous-Lebouc, A.; Hardy, V.

2012-06-01

Testing directly a magnetocaloric material in a magnetic refrigeration (MR) system is the best way to judge of its applicative potentialities. In this spirit, an oxide expected to show promising magnetocaloric properties around room temperature (Pr0.65Sr0.35MnO3) was produced in large scale and shaped in order to build a regenerator. Magnetization, heat capacity, resistivity, thermal conductivity and a direct test in a MR device were carried out on this manganite. The results were compared to those observed in the reference material which is Gadolinium. The two main conclusions of these preliminary results are: (i) the Pr0.65Sr0.35MnO3 actually displays not only a significant magnetocaloric effect but also a real refrigeration capability at room temperature; (ii) the temperature spans reached in these first experiments are even found to well compare with those obtained with Gd.

Hard permanent magnet development trends and their application to A.C. machines

NASA Technical Reports Server (NTRS)

Mildrum, H. F.

1981-01-01

The physical and magnetic properties of Mn-Al-C, Fe-Cr-Co, and RE-TM (rare earth-transition metal intermetallics) in polymer and soft metal bonded or sintered form are considered for ac circuit machine usage. The manufacturing processes for the magnetic materials are reviewed, and the mechanical and electrical properties of the magnetic materials are compared, with consideration given to the reference Alnico magnet. The Mn-Al-C magnets have the same magnetic properties and costs as Alnico units, operate well at low temperatures, but have poor high temperature performance. Fe-Cr-Co magnets also have comparable cost to Alnico magnets, and operate at high or low temperature, but are brittle, expensive, and contain Co. RE-Co magnets possess a high energy density, operate well in a wide temperature range, and are expensive. Recommendation for exploring the rare-earth alternatives are offered.

Decontamination System Utilizing Hydrogen Peroxide, UV Light and Catalytic Surfaces

DTIC Science & Technology

1992-02-01

Min %DMO RecoveredDisk# Catalyst (relative to control) 1 Ag 2 0 5.4 2 Ag2 0 10.1 4 FeTiO3 56 5 FeTio3 48 7 None 558 None 56 Control None 100 Ag 2 0...Std. Ag2 0 44 FeTiO3 Std. FeTiO3 100 Reference 87 - 36 - Table 9g. Experiment U, 1-09-91, 50% H2 02 , No UV Light, Run Time - 40 Min % DMO...Ag 2 0 2 7.8 44 1-09 T FeTiO3 2 52 100 1-09 U MnO 2 59 921-09 U Mn304 2 62 89 1-21 Y Ag 2 S/CaCO3 2 36 103 1-21 Y Ag 2 S 2 39 100 1-21 Z FeS2 2 6.0

Patents & Inventions: An Information Aid for Inventors. Revised Edition.

ERIC Educational Resources Information Center

Patent Office (DOC), Washington, DC.

This pamphlet explains what a patent is, discusses the importance of patents, and gives basic steps to take in obtaining a patent. A section on marketing and developing inventions is also included along with answers to questions frequently asked concerning patents and inventions. (MN)

Effects of microstructural variation on Charpy impact properties in heavy-section Mn-Mo-Ni low alloy steel for reactor pressure vessel

NASA Astrophysics Data System (ADS)

Hong, Seokmin; Song, Jaemin; Kim, Min-Chul; Choi, Kwon-Jae; Lee, Bong-Sang

2016-03-01

The effects of microstructural changes in heavy-section Mn-Mo-Ni low alloy steel on Charpy impact properties were investigated using a 210 mm thick reactor pressure vessel. Specimens were sampled from 5 different positions at intervals of 1/4 thickness from the inner surface to the outer surface. A detailed microstructural analysis of impact-fractured specimens showed that coarse carbides along the lath boundaries acted as fracture initiation sites, and cleavage cracks deviated at prior-austenite grain boundaries and bainite lath boundaries. Upper shelf energy was higher and energy transition temperature was lower at the surface positon, where fine bainitic microstructure with homogeneously distributed fine carbides were present. Toward the center, coarse upper bainite and precipitation of coarse inter-lath carbides were observed, which deteriorated impact properties. At the 1/4T position, the Charpy impact properties were worse than those at other positions owing to the combination of elongated-coarse inter-lath carbides and large effective grain size.

Late Devonian conodonts and event stratigraphy in northwestern Algerian Sahara

NASA Astrophysics Data System (ADS)

Mahboubi, Abdessamed; Gatovsky, Yury

2015-01-01

Conodonts recovered from the Late Devonian South Marhouma section comprise 5 genera with 31 species (3 undetermined). The fauna establishes the presence of MN Zones 5, undifferentiated 6/7, 8/10 for the Middle Frasnian, the MN Zones 11, 12, 13 for the Upper Frasnian as well as the Early through Late triangularis Zones in the basal Famennian. The outcropping lithological succession is one of mostly nodular calcilutites alternating with numerous marly and shaly deposits, which, in the lower and upper part, comprise several dysoxic dark shale intervals. Among these the Upper Kellwasser horizon can be precisely dated and as such the presence of the terminal Frasnian Kellwasser Event is recognized for the first time in Algeria. Both the Middlesex and Rhinestreet Events cannot yet be precisely located, but supposedly occur among the dark shale horizons in the lower part of the section. However, their assignment to a precise level has so far not been established. Though poor in conodont abundance the South Marhouma section provides first evidence of the presence of several Montagne Noire conodont zones within the so far widely unstudied Frasnian of the Ougarta Chain. As such it is considered representative for the northwestern Algerian Saoura region.

Evaluated activation cross sections of longer-lived radionuclides produced by deuteron induced reactions on natural nickel

NASA Astrophysics Data System (ADS)

Takács, S.; Tárkányi, F.; Király, B.; Hermanne, A.; Sonck, M.

2007-07-01

Activation cross sections for deuteron induced nuclear reactions on natural nickel target were studied by using a standard stacked foil technique and gamma spectrometry up to 50 MeV deuteron bombarding energy. Reaction products with half life of at least half an hour were studied. Experimental elemental activation cross sections were determined for reactions on nickel resulting in 61,64Cu, 56,57Ni, 55,56,57,58,60,61Co, 52,54,56Mn and 51Cr radionuclides and were compared with earlier measured data.

Radioactive by-products of a self-shielded cyclotron and the liquid target system for F-18 routine production.

PubMed

Kambali, I; Suryanto, H; Parwanto

2016-06-01

Routine production of F-18 radionuclide using proton beams accelerated in a cyclotron could potentially generate residual radioisotopes in the cyclotron vicinity which eventually become major safety concerns over radiation exposure to the workers. In this investigation, a typical 11-MeV proton, self-shielded cyclotron has been assessed for its residual radiation sources in the cyclotron's shielding, tank/chamber, cave wall as well as target system. Using a portable gamma ray spectroscopy system, the radiation measurement in the cyclotron environment has been carried out. Experimental results indicate that relatively long-lived radioisotopes such as Mn-54, Zn-65 and Eu-152 are detected in the inner and outer surface of the cyclotron shielding respectively while Mn-54 spectrum is observed around the cyclotron chamber. Weak intensity of Eu-152 radioisotope is again spotted in the inner and outer surface of the cyclotron cave wall. Angular distribution measurement of the Eu-152 shows that the intensity slightly drops with increasing observation angle relative to the proton beam incoming angle. In the target system, gamma rays from Co-56, Mn-52, Co-60, Mn-54, Ag-110 m are identified. TALYS-calculated nuclear cross-section data are used to study the origins of the radioactive by-products.

Effects of deformation-induced martensite and grain size on ductile-to-brittle transition behavior of austenitic 18Cr-10Mn-N stainless steels

NASA Astrophysics Data System (ADS)

Hwang, Byoungchul; Lee, Tae-Ho; Kim, Sung-Joon

2010-12-01

Effects of deformation-induced martensite and grain size on ductile-to-brittle transition behavior of austenitic 18Cr-10Mn-(0.3˜0.6)N stainless steels with different alloying elements were investigated by means of Charpy impact tests and microstructural analyses. The steels all exhibited ductile-to-brittle transition behavior due to unusual brittle fracture at low temperatures despite having a face-centered cubic structure. The ductileto-brittle transition temperature (DBTT) obtained from Chapry impact tests did not coincide with that predicted by an empirical equation depending on N content in austenitic Cr-Mn-N stainless steels. Furthermore, a decrease of grain size was not effective in terms of lowering DBTT. Electron back-scattered diffraction and transmission electron microscopy analyses of the cross-sectional area of the fracture surface showed that some austenites with lower stability could be transformed to α'-martensite by localized plastic deformation near the fracture surface. Based on these results, it was suggested that when austenitic 18Cr-10Mn-N stainless steels have limited Ni, Mo, and N content, the deterioration of austenite stability promotes the formation of deformation-induced martensite and thus increases DBTT by substantially decreasing low-temperature toughness.

Review of European electric propulsion developments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartoli, C.; Berry, W.

1987-05-01

European activities in the field of electric propulsion research, primarily under ESA sponsorship, are discussed. Attention is given to German RF ion thrusters using Xe gas propellant, a family of British Xe-propellant Kaufmann thrusters with outputs in the 10-200 mN range, the results of tests with the Field Emission Electric Propulsion system, Italian MPD thruster-related research, and recent developments in power-augmented catalytic thruster and resistojet electrothermal propulsion systems. 51 references.

Hierarchical Goal Network Planning: Initial Results

DTIC Science & Technology

2011-05-31

svikas@cs.umd.edu Ugur Kuter Smart Information Flow Technologies 211 North 1st Street Minneapolis, MN 55401 USA ukuter@sift.net Dana S. Nau Dept. of...inferred. References [1] Ron Alford, Ugur Kuter, and Dana S. Nau. Translating HTNs to PDDL: A small amount of domain knowledge can go a long way. In...10] Ugur Kuter, Dana S. Nau, Marco Pistore, and Paolo Traverso. Task decomposition on abstract states, for planning under nondeterminism. Artif

Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser

PubMed Central

Kupitz, Christopher; Basu, Shibom; Grotjohann, Ingo; Fromme, Raimund; Zatsepin, Nadia A.; Rendek, Kimberly N.; Hunter, Mark S.; Shoeman, Robert L.; White, Thomas A.; Wang, Dingjie; James, Daniel; Yang, Jay-How; Cobb, Danielle E.; Reeder, Brenda; Sierra, Raymond G.; Liu, Haiguang; Barty, Anton; Aquila, Andrew L.; Deponte, Daniel; Kirian, Richard A.; Bari, Sadia; Bergkamp, Jesse J.; Beyerlein, Kenneth R.; Bogan, Michael J.; Caleman, Carl; Chao, Tzu-Chiao; Conrad, Chelsie E.; Davis, Katherine M.; Fleckenstein, Holger; Galli, Lorenzo; Hau-Riege, Stefan P.; Kassemeyer, Stephan; Laksmono, Hartawan; Liang, Mengning; Lomb, Lukas; Marchesini, Stefano; Martin, Andrew V.; Messerschmidt, Marc; Milathianaki, Despina; Nass, Karol; Ros, Alexandra; Roy-Chowdhury, Shatabdi; Schmidt, Kevin; Seibert, Marvin; Steinbrener, Jan; Stellato, Francesco; Yan, Lifen; Yoon, Chunhong; Moore, Thomas A.; Moore, Ana L.; Pushkar, Yulia; Williams, Garth J.; Boutet, Sébastien; Doak, R. Bruce; Weierstall, Uwe; Frank, Matthias; Chapman, Henry N.; Spence, John C. H.; Fromme, Petra

2015-01-01

Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth’s oxygenic atmosphere1. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed2 technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the ‘dangler’ Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies3,4. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules. PMID:25043005

The influence of microtopography on soil nutrients in created mitigation wetlands

USGS Publications Warehouse

Moser, K.F.; Ahn, C.; Noe, G.B.

2009-01-01

This study explores the relationship between microtopography and soil nutrients (and trace elements), comparing results for created and reference wetlands in Virginia, and examining the effects of disking during wetland creation. Replicate multiscale tangentially conjoined circular transects were used to quantify microtopography both in terms of elevation and by two microtopographic indices. Corresponding soil samples were analyzed for moisture content, total C and N, KCl-extractable NH4-N and NO3-N, and Mehlich-3 extractable P, Ca, Mg, K, Al, Fe, and Mn. Means and variances of soil nutrient/element concentrations were compared between created and natural wetlands and between disked and nondisked created wetlands. Natural sites had higher and more variable soil moisture, higher extractable P and Fe, lower Mn than created wetlands, and comparatively high variability in nutrient concentrations. Disked sites had higher soil moisture, NH4-N, Fe, and Mn than did nondisked sites. Consistently low variances (Levene test for inequality) suggested that nondisked sites had minimal nutrient heterogeneity. Across sites, low P availability was inferred by the molar ratio (Mehlich-3 [P/(Al + Fe)] < 0.06); strong intercorrelations among total C, total N, and extractable Fe, Al, and P suggested that humic-metal-P complexes may be important for P retention and availability. Correlations between nutrient/element concentrations and microtopographic indices suggested increased Mn and decreased K and Al availability with increased surface roughness. Disking appears to enhance water and nutrient retention, as well as nutrient heterogeneity otherwise absent from created wetlands, thus potentially promoting ecosystem development. ?? 2008 Society for Ecological Restoration International.

Comparative genomics of Ceriporiopsis subvermispora and Phanerochaete chrysosporium provide insight into selective ligninolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez-Fueyo, Elena; Ruiz-Duenas, Francisco J.; Ferreira, Patrica

Efficient lignin depolymerization is unique to the wood decay basidiomycetes, collectively referred to as white rot fungi. Phanerochaete chrysosporium simultaneously degrades lignin and cellulose, whereas the closely related species, Ceriporiopsis subvermispora, also depolymerizes lignin but may do so with relatively little cellulose degradation. To investigate the basis for selective ligninolysis, we conducted comparative genome analysis of C. subvermispora and P. chrysosporium. Genes encoding manganese peroxidase numbered 13 and five in C. subvermispora and P. chrysosporium, respectively. In addition, the C. subvermispora genome contains at least seven genes predicted to encode laccases, whereas the P. chrysosporium genome contains none. We alsomore » observed expansion of the number of C. subvermispora desaturase-encoding genes putatively involved in lipid metabolism. Microarray-based transcriptome analysis showed substantial up-regulation of several desaturase and MnP genes in wood-containing medium. MS identified MnP proteins in C. subvermispora culture filtrates, but none in P. chrysosporium cultures. These results support the importance of MnP and a lignin degradation mechanism whereby cleavage of the dominant nonphenolic structures is mediated by lipid peroxidation products. Two C. subvermispora genes were predicted to encode peroxidases structurally similar to P. chrysosporium lignin peroxidase and, following heterologous expression in Escherichia coli, the enzymes were shown to oxidize high redox potential substrates, but not Mn2. Apart from oxidative lignin degradation, we also examined cellulolytic and hemicellulolytic systems in both fungi. In summary, the C. subvermispora genetic inventory and expression patterns exhibit increased oxidoreductase potential and diminished cellulolytic capability relative to P. chrysosporium.« less

Comparative genomics of Ceriporiopsis subvermispora and Phanerochaete chrysosporium provide insight into selective ligninolysis

PubMed Central

Fernandez-Fueyo, Elena; Ruiz-Dueñas, Francisco J.; Ferreira, Patricia; Floudas, Dimitrios; Hibbett, David S.; Canessa, Paulo; Larrondo, Luis F.; James, Tim Y.; Seelenfreund, Daniela; Lobos, Sergio; Polanco, Rubén; Tello, Mario; Honda, Yoichi; Watanabe, Takahito; Watanabe, Takashi; Ryu, Jae San; Kubicek, Christian P.; Schmoll, Monika; Gaskell, Jill; Hammel, Kenneth E.; St. John, Franz J.; Vanden Wymelenberg, Amber; Sabat, Grzegorz; Splinter BonDurant, Sandra; Syed, Khajamohiddin; Yadav, Jagjit S.; Doddapaneni, Harshavardhan; Subramanian, Venkataramanan; Lavín, José L.; Oguiza, José A.; Perez, Gumer; Pisabarro, Antonio G.; Ramirez, Lucia; Santoyo, Francisco; Master, Emma; Coutinho, Pedro M.; Henrissat, Bernard; Lombard, Vincent; Magnuson, Jon Karl; Kües, Ursula; Hori, Chiaki; Igarashi, Kiyohiko; Samejima, Masahiro; Held, Benjamin W.; Barry, Kerrie W.; LaButti, Kurt M.; Lapidus, Alla; Lindquist, Erika A.; Lucas, Susan M.; Riley, Robert; Salamov, Asaf A.; Hoffmeister, Dirk; Schwenk, Daniel; Hadar, Yitzhak; Yarden, Oded; de Vries, Ronald P.; Wiebenga, Ad; Stenlid, Jan; Eastwood, Daniel; Grigoriev, Igor V.; Berka, Randy M.; Blanchette, Robert A.; Kersten, Phil; Martinez, Angel T.; Vicuna, Rafael; Cullen, Dan

2012-01-01

Efficient lignin depolymerization is unique to the wood decay basidiomycetes, collectively referred to as white rot fungi. Phanerochaete chrysosporium simultaneously degrades lignin and cellulose, whereas the closely related species, Ceriporiopsis subvermispora, also depolymerizes lignin but may do so with relatively little cellulose degradation. To investigate the basis for selective ligninolysis, we conducted comparative genome analysis of C. subvermispora and P. chrysosporium. Genes encoding manganese peroxidase numbered 13 and five in C. subvermispora and P. chrysosporium, respectively. In addition, the C. subvermispora genome contains at least seven genes predicted to encode laccases, whereas the P. chrysosporium genome contains none. We also observed expansion of the number of C. subvermispora desaturase-encoding genes putatively involved in lipid metabolism. Microarray-based transcriptome analysis showed substantial up-regulation of several desaturase and MnP genes in wood-containing medium. MS identified MnP proteins in C. subvermispora culture filtrates, but none in P. chrysosporium cultures. These results support the importance of MnP and a lignin degradation mechanism whereby cleavage of the dominant nonphenolic structures is mediated by lipid peroxidation products. Two C. subvermispora genes were predicted to encode peroxidases structurally similar to P. chrysosporium lignin peroxidase and, following heterologous expression in Escherichia coli, the enzymes were shown to oxidize high redox potential substrates, but not Mn2+. Apart from oxidative lignin degradation, we also examined cellulolytic and hemicellulolytic systems in both fungi. In summary, the C. subvermispora genetic inventory and expression patterns exhibit increased oxidoreductase potential and diminished cellulolytic capability relative to P. chrysosporium. PMID:22434909

Increased risk of parkinsonism associated with welding exposure.

PubMed

Racette, Brad A; Criswell, Susan R; Lundin, Jessica I; Hobson, Angela; Seixas, Noah; Kotzbauer, Paul T; Evanoff, Bradley A; Perlmutter, Joel S; Zhang, Jing; Sheppard, Lianne; Checkoway, Harvey

2012-10-01

Manganese (Mn), an established neurotoxicant, is a common component of welding fume. The neurological phenotype associated with welding exposures has not been well described. Prior epidemiologic evidence linking occupational welding to parkinsonism is mixed, and remains controversial. This was a cross-sectional and nested case-control study to investigate the prevalence and phenotype of parkinsonism among 811 shipyard and fabrication welders recruited from trade unions. Two reference groups included 59 non-welder trade workers and 118 newly diagnosed, untreated idiopathic PD patients. Study subjects were examined by a movement disorders specialist using the Unified Parkinson Disease Rating Scale motor subsection 3 (UPDRS3). Parkinsonism cases were defined as welders with UPDRS3 score ≥15. Normal was defined as UPDRS3<6. Exposure was classified as intensity adjusted, cumulative years of welding. Adjusted prevalence ratios for parkinsonism were calculated in relation to quartiles of welding years. The overall prevalence estimate of parkinsonism was 15.6% in welding exposed workers compared to 0% in the reference group. Among welders, we observed a U-shaped dose-response relation between weighted welding exposure-years and parkinsonism. UPDRS3 scores for most domains were similar between welders and newly diagnosed idiopathic Parkinson disease (PD) patients, except for greater frequency of rest tremor and asymmetry in PD patients. This work-site based study among welders demonstrates a high prevalence of parkinsonism compared to nonwelding-exposed workers and a clinical phenotype that overlaps substantially with PD. Copyright © 2012 Elsevier Inc. All rights reserved.

Increased risk of parkinsonism associated with welding exposure

PubMed Central

Racette, Brad A.; Criswell, Susan R.; Lundin, Jessica I.; Hobson, Angela; Seixas, Noah; Kotzbauer, Paul T.; Evanoff, Bradley A.; Perlmutter, Joel S.; Zhang, Jing; Sheppard, Lianne; Checkoway, Harvey

2013-01-01

Objective Manganese (Mn), an established neurotoxicant, is a common component of welding fume. The neurological phenotype associated with welding exposures has not been well described. Prior epidemiologic evidence linking occupational welding to parkinsonism is mixed, and remains controversial. Methods This was a cross-sectional and nested case–control study to investigate the prevalence and phenotype of parkinsonism among 811 shipyard and fabrication welders recruited from trade unions. Two reference groups included 59 non-welder trade workers and 118 newly diagnosed, untreated idiopathic PD patients. Study subjects were examined by a movement disorders specialist using the Unified Parkinson Disease Rating Scale motor subsection 3 (UPDRS3). Parkinsonism cases were defined as welders with UPDRS3 score ≥15. Normal was defined as UPDRS3 < 6. Exposure was classified as intensity adjusted, cumulative years of welding. Adjusted prevalence ratios for parkinsonism were calculated in relation to quartiles of welding years. Results The overall prevalence estimate of parkinsonism was 15.6% in welding exposed workers compared to 0% in the reference group. Among welders, we observed a U-shaped dose–response relation between weighted welding exposure-years and parkinsonism. UPDRS3 scores for most domains were similar between welders and newly diagnosed idiopathic Parkinson disease (PD) patients, except for greater frequency of rest tremor and asymmetry in PD patients. Conclusion This work-site based study among welders demonstrates a high prevalence of parkinsonism compared to nonwelding-exposed workers and a clinical phenotype that overlaps substantially with PD. PMID:22975422

Effect of natural homointerfaces on the magnetic properties of pseudomorphic La0.7Sr0.3MnO3 thin film: Phase separation vs split domain structure

NASA Astrophysics Data System (ADS)

Congiu, Francesco; Sanna, Carla; Maritato, Luigi; Orgiani, Pasquale; Geddo Lehmann, Alessandra

2016-12-01

We studied the effect of naturally formed homointerfaces on the magnetic and electric transport behavior of a heavily twinned, 40 nm thick, pseudomorphic epitaxial film of La0.7Sr0.3MnO3 deposited by molecular beam epitaxy on ferroelastic LaAlO3(001) substrate. As proved by high resolution X-ray diffraction analysis, the lamellar twin structure of the substrate is imprinted in La0.7Sr0.3MnO3. In spite of the pronounced thermomagnetic irreversibility in the DC low field magnetization, spin-glass-like character, possibly related to the structural complexity, was ruled out, on the base of AC susceptibility results. The magnetic characterization indicates anisotropic ferromagnetism, with a saturation magnetization Ms = 3.2 μB/Mn, slightly reduced with respect to the fully polarized value of 3.7 μB/Mn. The low field DC magnetization vs temperature is non bulklike, with a two step increase in the field cooled MFC(T) branch and a two peak structure in the zero field cooled MZFC(T) one. Correspondingly, two peaks are present in the resistivity vs temperature ρ(T) curve. With reference to the behavior of epitaxial manganites deposited on bicrystal substrates, results are discussed in terms of a two phase model, in which each couple of adjacent ferromagnetic twin cores, with bulklike TC = 370 K, is separated by a twin boundary with lower Curie point TC = 150 K, acting as barrier for spin polarized transport. The two phase scenario is compared with the alternative one based on a single ferromagnetic phase with the peculiar ferromagnetic domains structure inherent to twinned manganites films, reported to be split into interconnected and spatially separated regions with in-plane and out-of-plane magnetization, coinciding with twin cores and twin boundaries respectively.

Two-Oxide Disequilibrium: A New Geospeedometer Based on Diffusion in Ilmenite

NASA Astrophysics Data System (ADS)

Williams, K. B.; Krawczynski, M. J.; Van Orman, J. A.

2016-12-01

Diffusion-annealing experiments were conducted in a 0.5" piston cylinder apparatus to investigate diffusivity of Fe2+, Mg2+, and Mn2+ in ilmenite solid solutions between 800ºC and 1000ºC. Polycrystalline ilmenite (FeTiO3) was juxtaposed against either an oriented geikielite (MgTiO3) single crystal or polycrystalline Mn-bearing (5 mol% Mn) ilmenite, in a "diffusion-couple" geometry. Geikielite single crystals were synthesized at Los Alamos National Laboratory, cut into 1 mm edge-length cubes, and polished either perpendicular or parallel to the c-axis. Polycrystalline ilmenite starting materials were synthesized by mixing high purity reagent-grade oxides (FeO, MnO, and TiO2) and sintering in a piston cylinder apparatus, then cut into wafers and polished. Experimental run products were analyzed by electron microprobe at Washington University in St. Louis. Microprobe analyses were obtained perpendicularly across the diffusion interface for each experiment. Experimental diffusion profiles create smooth curves that, when fit with an error function, define Fe-Mg and Fe-Mn interdiffusion coefficients in ilmenite. The diffusion coefficients do not appear compositionally dependent, but do show significant anisotropy. Preliminary results suggest diffusion activation energies are lower in ilmenite than in titanomagnetite [1]. Ilmenite-titanomagnetite equilibria define pre-eruptive temperatures and oxygen fugacities. However, oxides often exist out of equilibrium [2]. We use the cation diffusion data for ilmenite and existing data on titanomagnetite to establish two-oxide disequilibrium as a geospeedometer. Our data constrain oxide-oxide re-equilibration timescales at Mt. Unzen to months, consistent with estimates from zoned, single crystals of magnetite [3,4]. Future experiments will examine the effect of oxygen fugacity on diffusivity in ilmenite solid solutions. References:[1] Van Orman & Crispin (2010) RiMG 72, 757-825.[2] Bacon & Hirschmann (1988) Am. Min. 73, 57-61.[3] Nakamura (1995) Geology 23, 807-810.[4] Venezky & Rutherford (1999) J. Volc. Geo. Res. 89, 213-230.

Light in the darkening on Naica gypsum crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Esparza-Ponce, H. E.

2015-07-23

Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performedmore » at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe{sub 2}O{sub 3}), β-MnO{sub 2}, Mn{sub 2}O{sub 3}, MnO and/or MnCO{sub 3}, PbS, PbCO{sub 3} and/or PbSO4, ZnO{sub 4}, ZnS and/or smithsonite (ZnCO{sub 3}), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases.« less

Trace elements in muscle of three fish species from Todos os Santos Bay, Bahia State, Brazil.

PubMed

de Santana, Carolina Oliveira; de Jesus, Taíse Bomfim; de Aguiar, William Moura; de Jesus Sant'anna Franca-Rocha, Washington; Soares, Carlos Alberto Caroso

2017-03-01

In this study, an analysis was performed on the concentrations of the trace elements Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in muscle of two carnivorous and one planktivorous fish species collected at Todos os Santos Bay (BTS). The accumulation order of the trace elements in Lutjanus analis was Al >Zn >Fe >Cr >Ba >Ni. In Cetengraulis edentulus, the order was Al >Fe >Zn >Cr >Ni >Mn >As. In the species Diapterus rhombeus, the order was Al >Fe >Zn >Cr >Ni >Mn >Cd. To determine the risk related to the consumption of fish, toxicity guidelines were used as standard references. It was observed that the species C. edentulus contained concentrations of As exceeding WHO limits, but these concentrations were acceptable according to the Agência Nacional de Vigilância Sanitária (ANVISA) guidelines. Cd levels were found only in D. rhombeus and in low concentrations according to the determinations of WHO and ANVISA. Pb levels were not detected in any of the three fish species. The analyzed elements did not differ statistically according to the species and feeding habits. The results point to possible risks of human contamination by As related to the consumption of the fish species C. edentulus from the BTS.

Comparison of dry, wet and microwave digestion methods for the multi element determination in some dried fruit samples by ICP-OES.

PubMed

Altundag, Huseyin; Tuzen, Mustafa

2011-11-01

The aim of this study was used to investigate the level of trace metals (Ba, Pb, Cd, Mn, Cr, Co, Ni, Cu, Mn, Zn, Sr and Fe) in some dried fruits (Prunus domestica L., Ficus carica L., Morus alba L., Vitis vinifera L., Prunus armeniaca L., and Malus domestica) samples from Turkey. Trace elements were determined by ICP-OES after dry, wet and microwave digestion methods in dried fruit samples. Validation of the proposed method was carried out by using a NIST-SRM 1515-Apple Leaves certified reference material. Element concentrations in dried fruit samples were 0.33-1.77 (Ba), 0.12-0.54 (Cd), 0.25-1.03 (Co), 0.45-2.30 (Cr), 0.43-2.74 (Cu), 0.56-4.87 (Mn), 0.61-2.54 (Ni), 0.40-2.14 (Pb), 2.16-6.54 (Zn), 0.83-12.02 (Al), 11.82-40.80 (Fe) and 0.16-6.34 (Sr) μg/g. The analytical parameters show that the microwave oven digestion procedure provided best results as compared to the wet and dry digestion procedures. The results were compared with the literature values. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of the oxidation of enrofloxacin by permanganate and the antimicrobial activity of the products.

PubMed

Xu, Yongpeng; Liu, Shiyao; Guo, Fang; Zhang, Bo

2016-02-01

Permanganate [Mn(VII)] oxidation of the fluoroquinolone (FQ) antibiotic enrofloxacin (ENR) was investigated with respect to kinetics and mechanisms, and the products were evaluated for residual antibacterial activity. The degradation of ENR by Mn(VII) obeyed second-order kinetics. A modern liquid chromatography coupled to a hybrid quadrupole time-of-flight mass spectrometer (LC-Q-TOF) was used to determine the accurate mass of the measured degradation products. The structures of nine oxidation products were identified at a neutral pH, one of which was an N-oxide product formed from the oxidation of tertiary amines. One proposed plausible reaction pathway was that the oxidation occurred on the piperazine ring; the C-H adjacent to the amine group was attacked by Mn(VII). The identified products from ENR arose through four pathways involving two mechanisms of N-dealkylation, C-hydroxylation and the reactions of amine oxides. The quinolone core remained intact for all of the products. The residual antibacterial activity of the oxidative reaction byproducts against the nonresistant Escherichia coli (G(-)) reference strain DH5ɑ was evaluated by quantifying the bacterial colonies. The oxidation products exhibited reduced antibacterial activity compared with their parent compound. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of micromineral contents of school meals.

PubMed

Shin, Dongsoon

2014-08-01

Korean ordinary diets are referred to be good for human health in worldwide. However it is uncertain whether they provide microminerals enough for growth and health of teenagers. A main purpose of this study was to identify micromineral contents in school meals. The fifty cuisines were collected from elementary schools and middle schools in Gyeongnam area. The contents of Fe, Zn, Cu and Mn among microminerals were analyzed by using ICP-OES method. Data were expressed as mean, standard deviation and range value and linear regression analysis performed. Fe level of Pangibuseotpaprika-salad was the highest among side-dishes (average 346.6 µg) and Zn level of Sullung-tang was highest among soups (average 229.1 µg). Cu level of Buchu-kimchi was the highest among kimchies (average 217.5 µg) and Mn level of Gumeunkongyangnyum-gui was highest among side-dishes (average 198.4 µg). Generally cooked-rices as main dish had relative smaller amounts of microminerals than the other cuisines. The results showed that the ratio of Cu : Fe : Zn was approximately 12 : 4 : 1 and the relationship between Fe versus Zn or Fe versus Cu was significantly positive. Comparing to Korean Dietary Recommended Intakes (KDRI) level, school meals provided not sufficient amount (<25% DRI) of Fe, Zn or Mn, while they did excessive amount (>125% DRI) of Cu.

Bioaccumulation of Heavy Metals in Water, Sediments, and Tissues and Their Histopathological Effects on Anodonta cygnea (Linea, 1876) in Kabul River, Khyber Pakhtunkhwa, Pakistan

PubMed Central

Khan, Muhammad Iftikhar; Gulfam, Naila; Siraj, Muhammad; Zaidi, Farrah; Ahmadullah; Abidullah; Fatima, Syeda Hira; Noreen, Shumaila; Hamidullah; Shah, Zafar Ali; Qadir, Fazli

2018-01-01

The present investigation aimed to assess the concentrations of selected heavy metals in water and sediments and their bioaccumulation in tissues of freshwater mussels and their histopathological effects on the digestive gland, gills, and gonads of Anodonta cygnea. Water, sediments, and freshwater mussel samples were collected at four sites, that is, reference and polluted sites, along the Kabul River, Khyber Pakhtunkhwa. The polluted sites were receiving effluents from the industrial, agricultural, municipal, and domestic sources. The order of metals in the water was Zn > Pb > Ni > Cu > Mn > Fe > Cr > Cd, in sediments the order was Fe > Zn > Cr > Ni > Mn > Pb > Cu > Cd, and in the soft tissues the order was Fe > Zn > Mn > Pb > Cu > Cr > Ni > Cd. Histopathological alterations observed in polluted sites of Kabul River were inflammation, hydropic vacuolation, and lipofuscin pigments (in digestive gland), gill lamellar fusion, dilated hemolymphatic sinus, clumping, and generation of cilia and hemocytic infiltration (in gills), and atresia, necrosis, granulocytoma, hemocytic infiltration, and lipofuscin pigments (in gonads). The histopathological alterations in the organs of Anodonta cygnea can be considered as reliable biomarkers in biomonitoring of heavy metal pollution in aquatic ecosystems. PMID:29693003

Bioavailability of trace metals in sediments of a recovering freshwater coastal wetland in China's Yellow River Delta, and risk assessment for the macrobenthic community.

PubMed

Yang, Wei; Li, Xiaoxiao; Pei, Jun; Sun, Tao; Shao, Dongdong; Bai, Junhong; Li, Yanxia

2017-12-01

We investigated the speciation of trace metals and their ecological risks to macrobenthic communities in a recovering coastal wetland of China's Yellow River Delta during the freshwater release project. We established 16 sampling sites in three restoration areas and one intertidal reference area, and collected sediments and macrobenthos four times from 2014 to 2015. The instability index for the trace metals showed a moderate risk for Mn and a high risk for Cd. For both Mn and Cd, the carbonate and FeMn-bound fractions appear to contribute mostly to the instability and bioavailability indexes, but for Cd, the exchangeable fraction also have a much higher contribution. The bioavailability index indicated higher bioavailability of trace metals in freshwater restoration areas than that in the intertidal area. The single-factor contamination index indicated that most trace metal concentrations in the macrobenthos were in excess of the national standard. The biota-sediment accumulation factor suggested that the macrobenthos accumulated most As, Cd, and Cu. Redundancy analysis showed clear relationships between the macrobenthos and sediment metal concentrations. Our results will help wetland managers to assess the bioaccumulation risks based on metal speciation, and to improve management of these recovering freshwater wetland ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of excess nitrogen on biogeochemistry of a temperate hardwood forest: Evidence of nutrient redistribution by a forest understory species

NASA Astrophysics Data System (ADS)

Gilliam, Frank S.; Billmyer, Jake H.; Walter, Christopher A.; Peterjohn, William T.

2016-12-01

Excess nitrogen (N) in terrestrial ecosystems can arise from anthropogenically-increased atmospheric N deposition, a phenomenon common in eastern US forests. In spite of decreased N emissions over recent years, atmospheric concentrations of reactive N remain high in areas within this region. Excess N in forests has been shown to alter biogeochemical cycling of essential plant nutrients primarily via enhanced production and leaching of nitrate, which leads to loss of base cations from the soil. The purpose of our study was to investigate this phenomenon using a multifaceted approach to examine foliar nutrients of two herbaceous layer species in one N-treated watershed (WS3-receiving aerial applications of 35 kg N/ha/yr as ammonium sulfate, from 1989 to the present) and two untreated reference watersheds at the Fernow Experimental Forest, WV, USA. In 1993, we analyzed foliar tissue of Viola rotundifolia, a dominant herb layer species and prominent on all seven sample plots in each watershed. In 2013 and 2014, we used foliar tissue from Rubus allegheniensis, which had become the predominant species on WS3 and had increased, though to a lesser extent, in cover on both reference watersheds. Foliar N and potassium (K) were higher and foliar calcium (Ca) was lower on WS3 than on the reference watersheds for both species. Magnesium (Mg) was lower on WS3 for Viola, but was not different among watersheds for Rubus. Results support the stream chemistry-based observation that excess N lowers plant-available Ca and, to a lesser degree, Mg, but not of K. Foliar manganese (Mn) of Rubus averaged >4 times that of Viola, and was >50% higher on WS3 than on the reference watersheds. A Mn-based mechanism is proposed for the N-meditated increase in Rubus on WS3. Data suggest that excess N deposition not only alters herb community composition and biogeochemical cycling of forest ecosystems, but can do so simultaneously and interactively.

Reference levels of trace elements in hair samples from children and adolescents in Madrid, Spain.

PubMed

Llorente Ballesteros, María Teresa; Navarro Serrano, Irene; Izquierdo Álvarez, Silvia

2017-09-01

Hair samples are used as a tool to evaluate environmental exposure to contaminants and metabolic status in the individual. However, the use of human hair is controversial, mainly because of the lack of well-defined reference levels. In the case of Spain, very few biomonitoring studies have investigated these issues in infants, children or adolescents. To establish reference levels for trace elements in children and teenagers in Madrid, Spain. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure Al, As, Ag, Ba, Bi, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sr, Tl and Zn levels in hair samples from 648 healthy children and adolescents (253 boys and 395 girls) between April 2008 and December 2009. Median levels were as follows: Al 18.5μg/g, As 0.07μg/g, Ag 196ng/g, Ba 0.5μg/g, Bi 0.01μg/g, Cd 18.3ng/g, Cr 0.4μg/g, Co 14.5ng/g, Cu 25.7μg/g, Fe 15.5μg/g, Mn 328ng/g, Mo 0.04μg/g, Ni 0.5μg/g, Pb 0.70μg/g, Se 0.5μg/g, Sr 1.29μg/g, Tl 0.28ng/g and Zn 121μg/g. The values of trace elements here described could be considered as possible reference ranges for hair samples from children and adolescents aged 0-18 years living in the Madrid region (central Spain). These values could also be selected as a preliminary screening tool to assess exposure sources and to generate information needed to develop prevention strategies and likewise could be a complement to other diagnostic procedures. Copyright © 2016 Elsevier GmbH. All rights reserved.

Referred pain location depends on the affected section of the sacroiliac joint.

PubMed

Kurosawa, Daisuke; Murakami, Eiichi; Aizawa, Toshimi

2015-03-01

Pain referred from the sacroiliac joint (SIJ) may originate in the joint's posterior ligamentous region. The site of referred pain may depend on which SIJ section is affected. This study aimed to determine the exact origin of pain referred from four SIJ sections. The study included 50 patients with SIJ dysfunction, confirmed by more than 70 % pain relief after periarticular injection of local anesthetic into the SIJ. The posterior SIJ was divided into four sections-upper, middle, lower, and other (cranial portion of the ilium outside the SIJ)-designated sections 1, 2, 3, and 0, respectively. We then inserted a needle into the periarticular SIJ under fluoroscopy. After the patient identified the area(s) in which the needle insertion produced referred pain, we injected a mixture of 2 % lidocaine and contrast medium into the corresponding SIJ section. Referred pain from SIJ section 0 was mainly located in the upper buttock along the iliac crest; pain from section 1, around the posterosuperior iliac spine; pain from section 2, in the middle buttock area; pain from section 3, in the lower buttock. In all, 22 (44.0 %) patients complained of groin pain, which was slightly relieved by lidocaine injection into SIJ sections 1 and 0. Dysfunctional upper sections of the SIJ are associated with pain in the upper buttock and lower sections with pain in the lower buttock. Groin pain might be referred from the upper SIJ sections.

[Dietary reference intakes of trace elements for Japanese and problems in clinical fields].

PubMed

Inoue, Yoshifumi

2016-07-01

In the dietary reference intakes, EAR(estimated average requirement), RDA(recommended dietary allowance), AL(adequate intake), DG(tentative dietary goal for preventing life style related diseases) and UL(tolerable upper intake level) of eight types of trace elements (iron: Fe, zinc: Zn, copper: Cu, manganese: Mn, iodine: I, selenium: Se, chromium: Cr, molybdenum: Mo) have been set. However, in the meals of hospitals, only iron of which has been taken into account. The content of these trace elements in the enteral nutrient released after 2000 was determined by considering the content of dietary reference intakes of trace elements for Japanese and considered so not fall into deficiency. However, enteral nutrient must be used considering the content of Zn, Cu and the Zn/Cu ratio, the selenium content, and the route of administration, in order to avoid falling into deficiency.

Dissociative excitation of the manganese atom quartet levels by collisions e-MnBr2

NASA Astrophysics Data System (ADS)

Smirnov, Yu M.

2017-04-01

Dissociative excitation of quartet levels of the manganese atom was studied in collisions of electrons with manganese dibromide molecules. Eighty-two cross-sections for transitions originating at odd levels and eleven cross-sections for transitions originating at even levels have been measured at an incident electron energy of 100 eV. An optical excitation function has been recorded in the electron energy range of 0-100 eV for transitions originating from 3d 64p z 4 F° levels. For the majority of transitions, a comparison of the resulting cross-section values to cross-sections produced by direct excitation is provided.

Trace element reference intervals in the blood of healthy green sea turtles to evaluate exposure of coastal populations.

PubMed

Villa, C A; Flint, M; Bell, I; Hof, C; Limpus, C J; Gaus, C

2017-01-01

Exposure to essential and non-essential elements may be elevated for green sea turtles (Chelonia mydas) that forage close to shore. Biomonitoring of trace elements in turtle blood can identify temporal trends over repeated sampling events, but any interpretation of potential health risks due to an elevated exposure first requires a comparison against a baseline. This study aims to use clinical reference interval (RI) methods to produce exposure baseline limits for essential and non-essential elements (Na, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba, and Pb) using blood from healthy subadult turtles foraging in a remote and offshore part of the Great Barrier Reef. Subsequent blood biomonitoring of three additional coastal populations, which forage in areas dominated by agricultural, urban and military activities, showed clear habitat-specific differences in blood metal profiles relative to the those observed in the offshore population. Coastal turtles were most often found to have elevated concentrations of Co, Mo, Mn, Mg, Na, As, Sb, and Pb relative to the corresponding RIs. In particular, blood from turtles from the agricultural site had Co concentrations ranging from 160 to 840 μg/L (4-25 times above RI), which are within the order expected to elicit acute effects in many vertebrates. Additional clinical blood biochemistry and haematology results indicate signs of a systemic disease and the prevalence of an active inflammatory response in a high proportion (44%) of turtles from the agricultural site. Elevated Co, Sb, and Mn in the blood of these turtles significantly correlated with elevated markers of acute inflammation (total white cell counts) and liver dysfunction (alkaline phosphatase and total bilirubin). The results of this study support the notion that elevated trace element exposures may be adversely affecting the health of nearshore green sea turtles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anthropogenic land uses elevate metal levels in stream water in an urbanizing watershed.

PubMed

Yu, Shen; Wu, Qian; Li, Qingliang; Gao, Jinbo; Lin, Qiaoying; Ma, Jun; Xu, Qiufang; Wu, Shengchun

2014-08-01

Land use/cover change is a dominant factor affecting surface water quality in rapidly developing areas of Asia. In this study we examined relationships between land use and instream metal loadings in a rapidly developing mixed land use watershed in southeastern China. Five developing subwatersheds and one forested reference site (head water) were instrumented with timing- and rainfall-triggered autosampler and instream loadings of anthropogenic metals (Cu, Zn, Pb, Cr, Cd, and Mn) were monitored from March 2012 to December 2013. Farm land and urban land were positively, and forest and green land were negatively associated with metal loadings (except Cr) in stream water. All developing sites had higher loadings than the reference head water site. Assessed by Chinese surface water quality standard (GB3830-2002), instream loadings of Cu and Zn occasionally exceeded the Class I thresholds at monitoring points within farmland dominated subwatersheds while Mn loadings were greater than the limit for drinking water sources at all monitoring points. Farm land use highly and positively contributed to statistical models of instream loadings of Cu, Zn, Cd, and Mn while urban land use was the dominant contributor to models of Pb and Cd loadings. Rainfall played a crucial role in metal loadings in stream water as a direct source (there were significant levels of Cu and Zn in rain water) and as a driver of watershed processes (loadings were higher in wet years and seasons). Urbanization effects on metal loadings in this watershed are likely to change rapidly with development in future years. Further monitoring to characterize these changes is clearly warranted and should help to develop plans to avoid conflicts between economic development and water quality degradation in this watershed and in watersheds throughout rapidly developing areas of Asia. Copyright © 2014 Elsevier B.V. All rights reserved.

15. Photographic copy of blueprints and plans (from the originals ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Photographic copy of blueprints and plans (from the originals in possession of Detroit District, U.S. Army Corps of Engineers, Duluth, Minnesota). North pier of Duluth Canal, 1899, crib sections - Duluth Ship Canal, North Pier, North end of Minnesota Point at Canal Park, Duluth, St. Louis County, MN

40 CFR 63.11169 - What is the purpose of this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...? 63.11169 Section 63.11169 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Surface Coating Operations at Area Sources What This Subpart Covers § 63.11169 What is the purpose of this... containing compounds of chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), or cadmium (Cd), collectively...

40 CFR 63.11169 - What is the purpose of this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...? 63.11169 Section 63.11169 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Surface Coating Operations at Area Sources What This Subpart Covers § 63.11169 What is the purpose of this... containing compounds of chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), or cadmium (Cd), collectively...

40 CFR 63.11169 - What is the purpose of this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...? 63.11169 Section 63.11169 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Surface Coating Operations at Area Sources What This Subpart Covers § 63.11169 What is the purpose of this... containing compounds of chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), or cadmium (Cd), collectively...

40 CFR 63.11169 - What is the purpose of this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...? 63.11169 Section 63.11169 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Surface Coating Operations at Area Sources What This Subpart Covers § 63.11169 What is the purpose of this... containing compounds of chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), or cadmium (Cd), collectively...

40 CFR 63.11169 - What is the purpose of this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...? 63.11169 Section 63.11169 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Surface Coating Operations at Area Sources What This Subpart Covers § 63.11169 What is the purpose of this... containing compounds of chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), or cadmium (Cd), collectively...

Formation of Fe-Mn crusts within a continental margin environment

USGS Publications Warehouse

Conrad, Tracey A.; Hein, James R.; Paytan, Adina; Clague, David A.

2017-01-01

This study examines Fe-Mn crusts that form on seamounts along the California continental-margin (CCM), within the United States 200 nautical mile exclusive economic zone. The study area extends from approximately 30° to 38° North latitudes and from 117° to 126° West longitudes. The area of study is a tectonically active northeast Pacific plate boundary region and is also part of the North Pacific Subtropical Gyre with currents dominated by the California Current System. Upwelling of nutrient-rich water results in high primary productivity that produces a pronounced oxygen minimum zone. Hydrogenetic Fe-Mn crusts forming along the CCM show distinct chemical and mineral compositions compared to open-ocean crusts. On average, CCM crusts contain more Fe relative to Mn than open-ocean Pacific crusts. The continental shelf and slope release both Fe and Mn under low-oxygen conditions. Silica is also enriched relative to Al compared to open-ocean crusts. This is due to the North Pacific silica plume and enrichment of Si along the path of deep-water circulation, resulting in Si enrichment in bottom and intermediate waters of the eastern Pacific.The CCM Fe-Mn crusts have a higher percentage of birnessite than open-ocean crusts, reflecting lower dissolved seawater oxygen that results from the intense coastal upwelling and proximity to zones of continental slope pore-water anoxia. Carbonate fluorapatite (CFA) is not present and CCM crusts do not show evidence of phosphatization, even in the older sections. The mineralogy indicates a suboxic environment under which birnessite forms, but in which pH is not high enough to facilitate CFA deposition. Growth rates of CCM crusts generally increase with increasing water depth, likely due to deep-water Fe sources mobilized from reduced shelf and slope sediments.Many elements of economic interest including Mn, Co, Ni, Cu, W, and Te have slightly or significantly lower concentrations in CCM crusts relative to crusts from the Pacific Prime Crust Zone and other open-ocean basins. However, concentrations of total rare earth elements and yttrium average only slightly lower contents and in the future may be a strategic resource for the U.S.

Assessment of health risk of trace metal pollution in surface soil and road dust from e-waste recycling area in China

PubMed Central

Yekeen, Taofeek Akangbe; Xu, Xijin; Zhang, Yuling; Wu, Yousheng; Kim, Stephani; Reponen, Tiina; Dietrich, Kim N.; Ho, Shuk-mei; Chen, Aimin; Huo, Xia

2017-01-01

Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden on the ecosystem in Guiyu, China. In this investigation, we evaluated the trace metals concentration of community soil and road dust samples from 11 locations in Guiyu and 5 locations (consists of residential areas, kindergarten/school and farm field) in a reference area using graphite furnace atomic absorption spectrophotometer. The study spanned four seasons, 2012–2013, with a view to assess the risk associated with e-waste recycling in the study area. The concentration of Pb, Cd, Cr and Mn were 448.73, 0.71, 63.90 and 806.54 mg/kg in Guiyu soil and 589.74, 1.94, 69.71 and 693.74 mg/kg, in the dust, respectively. Pb and Cd values were significantly higher (P≤ 0.05) than the reference area and the mixed model analysis with repeated seasonal measurements revealed soil Pb and Cd levels that were 2.32 and 4.34 times, while the ratios for dust sample were 4.10 and 3.18 times higher than the reference area. Contamination factor, degree of contamination and pollution load index indicated that all sampling points had high level of metal contamination except farm land and kindergarten compound. The cumulative hazard index of Pb, Cd, Cr and Mn for children in exposed area was 0.99 and 1.62 for soil and dust respectively, suggesting non-cancer health risk potential. The significant accumulation of trace metals in the e-waste recycling area predisposes human life, especially children, to a potentially serious health risk. PMID:27230155

Assessment of health risk of trace metal pollution in surface soil and road dust from e-waste recycling area in China.

PubMed

Yekeen, Taofeek Akangbe; Xu, Xijin; Zhang, Yuling; Wu, Yousheng; Kim, Stephani; Reponen, Tiina; Dietrich, Kim N; Ho, Shuk-Mei; Chen, Aimin; Huo, Xia

2016-09-01

Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden on the ecosystem in Guiyu, China. In this investigation, we evaluated the trace metal concentration of community soil and road dust samples from 11 locations in Guiyu and 5 locations (consisting of residential areas, kindergarten/school, and farm field) in a reference area using graphite furnace atomic absorption spectrophotometer. The study spanned four seasons, 2012-2013, with a view to assess the risk associated with e-waste recycling in the study area. The concentrations of Pb, Cd, Cr, and Mn were 448.73, 0.71, 63.90, and 806.54 mg/kg in Guiyu soil and 589.74, 1.94, 69.71, and 693.74 mg/kg, in the dust, respectively. Pb and Cd values were significantly higher (P ≤ 0.05) than the reference area, and the mixed model analysis with repeated seasonal measurements revealed soil Pb and Cd levels that were 2.32 and 4.34 times, while the ratios for dust sample were 4.10 and 3.18 times higher than the reference area. Contamination factor, degree of contamination, and pollution load index indicated that all sampling points had a high level of metal contamination except farm land and kindergarten compound. The cumulative hazard index of Pb, Cd, Cr, and Mn for children in exposed area was 0.99 and 1.62 for soil and dust, respectively, suggesting non-cancer health risk potential. The significant accumulation of trace metals in the e-waste recycling area predisposes human life, especially children, to a potentially serious health risk.

The electronic spectrum of manganese hydride

NASA Astrophysics Data System (ADS)

Balfour, Walter J.

1988-04-01

The electronic spectrum of MnH is discussed with particular reference to the infrared system near 847 nm, which is assigned by rotational analysis to a 5 Σ-5 Σ transition, and the 480 nm system which is assigned to a 5 Π-5 Σ transition. The two systems have the same lower state. Bond lengths in the lower 5 Σ, the upper 5 Σ and the 5 Π states are 0.1638, 0.1655, and 0.1674 nm, respectively.

Ab initio calculation of the electronic structures of the (7)Sigma+ ground and A (7)Pi and a (5)Sigma+ excited states of MnH.

PubMed

Tomonari, Mutsumi; Nagashima, Umpei; Hirano, Tsuneo

2009-04-21

Electronic structures and molecular constants of the ground (7)Sigma(+) and low-lying A (7)Pi and a (5)Sigma(+) electronic excited states of the MnH molecule were studied by multireference single and double excitation configuration interaction (MR-SDCI) with Davidson's correction (+Q) calculations under exact C(infinity v) symmetry using Slater-type basis sets. To correctly describe the (7)Sigma(+) electronic ground state, X (7)Sigma(+), at the MR-SDCI+Q calculation, we employed a large number of reference configurations in terms of the state-averaged complete active space self-consistent field (CASSCF) orbitals, taking into account the contribution from the B (7)Sigma(+) excited state. The A (7)Pi and a (5)Sigma(+) states can well be described by the MR-SDCI wave functions based on the CASSCF orbitals obtained for the lowest state only. In the MR-SDCI+Q, calculations of the X (7)Sigma(+), A (7)Pi, and a (5)Sigma(+) states required 16, 7, and 17 reference configurations, respectively. Molecular constants, i.e., r(e) and omega(e) of these states and excitation energy from the X (7)Sigma(+) state, obtained at the MR-SDCI+Q level, showed a good agreement with experimental values. The small remaining differences may be accounted for by taking relativistic effects into account.

Ab initio calculation of the electronic structures of the 7∑+ ground and A 7Π and a 5∑+ excited states of MnH

NASA Astrophysics Data System (ADS)

Tomonari, Mutsumi; Nagashima, Umpei; Hirano, Tsuneo

2009-04-01

Electronic structures and molecular constants of the ground ∑7+ and low-lying A 7Π and a ∑5+ electronic excited states of the MnH molecule were studied by multireference single and double excitation configuration interaction (MR-SDCI) with Davidson's correction (+Q) calculations under exact C∞v symmetry using Slater-type basis sets. To correctly describe the ∑7+ electronic ground state, X ∑7+, at the MR-SDCI+Q calculation, we employed a large number of reference configurations in terms of the state-averaged complete active space self-consistent field (CASSCF) orbitals, taking into account the contribution from the B ∑7+ excited state. The A 7Π and a ∑5+ states can well be described by the MR-SDCI wave functions based on the CASSCF orbitals obtained for the lowest state only. In the MR-SDCI+Q, calculations of the X ∑7+, A 7Π, and a ∑5+ states required 16, 7, and 17 reference configurations, respectively. Molecular constants, i.e., re and ωe of these states and excitation energy from the X ∑7+ state, obtained at the MR-SDCI+Q level, showed a good agreement with experimental values. The small remaining differences may be accounted for by taking relativistic effects into account.

Characterization of airborne and bulk particulate from iron and steel manufacturing facilities.

PubMed

Machemer, Steven D

2004-01-15

Characterization of airborne and bulk particulate material from iron and steel manufacturing facilities, commonly referred to as kish, indicated graphite flakes and graphite flakes associated with spherical iron oxide particles were unique particle characteristics useful in identifying particle emissions from iron and steel manufacturing. Characterization of airborne particulate material collected in receptor areas was consistent with multiple atmospheric release events of kish particles from the local iron and steel facilities into neighboring residential areas. Kish particles deposited in nearby residential areas included an abundance of graphite flakes, tens of micrometers to millimeters in size, and spherical iron oxide particles, submicrometer to tens of micrometers in size. Bulk kish from local iron and steel facilities contained an abundance of similar particles. Approximately 60% of blast furnace kish by volume consisted of spherical iron oxide particles in the respirable size range. Basic oxygen furnace kish contained percent levels of strongly alkaline components such as calcium hydroxide. In addition, concentrations of respirable Mn in airborne particulate in residential areas and at local iron and steel facilities were approximately 1.6 and 53 times the inhalation reference concentration of 0.05 microg/m3 for chronic inhalation exposure of Mn, respectively. Thus, airborne release of kish may pose potential respirable particulate, corrosive, or toxic hazards for human health and/or a corrosive hazard for property and the environment.

Inductively coupled plasma atomic fluorescence spectrometric determination of cadmium, copper, iron, lead, manganese and zinc

USGS Publications Warehouse

Sanzolone, R.F.

1986-01-01

An inductively coupled plasma atomic fluorescence spectrometric method is described for the determination of six elements in a variety of geological materials. Sixteen reference materials are analysed by this technique to demonstrate its use in geochemical exploration. Samples are decomposed with nitric, hydrofluoric and hydrochloric acids, and the residue dissolved in hydrochloric acid and diluted to volume. The elements are determined in two groups based on compatibility of instrument operating conditions and consideration of crustal abundance levels. Cadmium, Cu, Pb and Zn are determined as a group in the 50-ml sample solution under one set of instrument conditions with the use of scatter correction. Limitations of the scatter correction technique used with the fluorescence instrument are discussed. Iron and Mn are determined together using another set of instrumental conditions on a 1-50 dilution of the sample solution without the use of scatter correction. The ranges of concentration (??g g-1) of these elements in the sample that can be determined are: Cd, 0.3-500; Cu, 0.4-500; Fe, 85-250 000; Mn, 45-100 000; Pb, 5-10 000; and Zn, 0.4-300. The precision of the method is usually less than 5% relative standard deviation (RSD) over a wide concentration range and acceptable accuracy is shown by the agreement between values obtained and those recommended for the reference materials.

Recent Compositional Trends within the Murray Formation, Gale Crater, Mars, as seen by APXS: Implications for Sedimentary, Diagenetic and Alteration History.

NASA Astrophysics Data System (ADS)

Thompson, L. M.; Yen, A.; Spray, J. G.; Johnson, J. R.; Fraeman, A. A.; Berger, J. A.; Gellert, R.; Boyd, N.; Desouza, E.; O'Connell-Cooper, C.; VanBommel, S.

2017-12-01

The >230 m thick Murray Formation is the lower-most unit of the Mount Sharp Group, and interpreted as primarily lacustrine. Representative mudstone, siltstone and fine sandstone targets, encountered above -4330 m elevation, trend to lower Si, Al, Ti, Cr and Ca, and higher Fe, Mn, Zn, P and Mg than the Murray below. Less common, distinctive, coarser grained sandstone lenses tend to exhibit slightly different compositions to the more typical Murray but, overall, show similar elemental trends with elevation, albeit exaggerated. This suggests that the variations observed with elevation in Al, Ti, Cr, K, Fe, Mn, Zn and P within both the coarser sandstones and finer grained Murray are the result of diagenetic and/or alteration processes rather than provenance or physical sedimentary processes such as sorting. This is supported by the chemistry of obvious diagenetic, dark grey nodules, and other potential diagenetic/alteration features within this section, which show variations in the same element concentrations (i.e., P, Mn, Fe, Zn, Mg, Ca and S), distinct from diagenetic features lower down in the stratigraphy, indicating mobility of these elements within this section and changing fluid chemistry. Trends in FeO/MnO generally mimic the presence of ferric absorption features observed in visible/near infrared passive spectra from the ChemCam instrument and from CRISM orbital data, which may be consistent with changes in redox conditions as we climb up section towards Vera Rubin Ridge (Hematite Ridge). Layer-parallel CaSO4 is also common, and not observed below -4330 m. This may represent syndepositional evaporite layers, or late bedding/laminae parallel veins emplaced after lithification, in conjunction with cross-cutting veins. The overall differences in composition between the sandstone targets and finer grained Murray are attributed to distinct provenances and/or sorting during transport. We will discuss the implications of the trends and composition of the Murray above -4330 m elevation and how this pertains to the history and evolution of the Murray Formation as a whole, climatic conditions during the formation of the Murray and the nature of Gale crater lake. Also, what do the trends imply about how circulating fluids have evolved within the Murray sediments and pH, redox, salinity conditions of these fluids?

Microstructure, magnetic and magnetocaloric properties in Ni42.9Co6.9Mn38.3Sn11.9 alloy ribbons

NASA Astrophysics Data System (ADS)

Ma, S. C.; Ge, Q.; Yang, S.; Liu, K.; Han, X. Q.; Yu, K.; Song, Y.; Zhang, Z. S.; Jiang, Q. Z.; Chen, C. C.; Liu, R. H.; Zhong, Z. C.

2018-05-01

The microstructure, magnetic and magnetocaloric properties are investigated in the melt-spun and annealed Ni42.9Co6.9Mn38.3Sn11.9 ribbons. The columnar grains grow perpendicular to ribbon surfaces. After annealing, the grain size increases greatly. Meanwhile, the parent phase is suppressed and therefore L10 martensite predominates, indicating obvious shift of martensitic transformation to high temperature. More interestingly, the martensite variants are distinctly observed on the fractured cross-section of annealed ribbons, not just on the free surface in general. The significant enhancement of magnetic entropy change and effective refrigerant capacities with relatively smaller thermal hysteresis make annealed ribbons potential candidate in magnetic refrigeration around room temperature.

Permanent magnet properties of Mn-Al-C between -50 C and +150 C

NASA Technical Reports Server (NTRS)

Abdelnour, Z. A.; Mildrum, H. F.; Strnat, K. J.

1981-01-01

Anisotropic Mn-Al-C (Ni) magnets are potential substitutes for Alnico 5 and 8. The limited machinability of the alloy and the fact that it is cobalt-free made it particularly interesting. The low Curie point and the costly warm extrusion process needed for grain orientation are drawbacks. The objective of this study was a detailed magnetic characterization of the material for possible use in electric machinery. The principal subjects of the study were the largest extruded bars presently available, of 31 mm diameter. Easy and hard axis magnetization curves and second-quadrant recoil loop fields were measured at various temperatures ranging from -50 C to +150 C. Property variations over the cross section of a bar were also studied.

Nouvelles découvertes de Vertébrés miocènes dans le synclinal de Dera Bugti (Balouchistan, Pakistan)

NASA Astrophysics Data System (ADS)

Welcomme, Jean-Loup; Antoine, Pierre-Olivier; Duranthon, Francis; Mein, Pierre; Ginsburg, Léonard

1997-10-01

Since Forster-Cooper in 1910, no paleontologist bas visited the area of Dera Bugti in Baluchistan (Pakistan). In 1995 and 1996, two small French expeditions prospected the syncline of Dera Bugti. They established stratigraphical sections ana discovered many fossils, mainly reptiles, and mammals. On top of the Eocene marine limestone of the Kirthar there lies a Burdigalian marine falun. Above, about 250 m of continental marls, sands and sandstones are deposited. The first 100 m have yielded five fossiliferous levels of MN3 b in age, and one of MN4, surrounded by a more sandy series. The top of the series has yielded Hipparion of the Upper Miocene.

Nuclear level densities in {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, and {sup 54}Mn from neutron evaporation spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuravlev, B. V., E-mail: zhurav@ippe.ru; Lychagin, A. A.; Titarenko, N. N.

The spectra of neutrons from the (p, n) reactions on {sup 47}Ti, {sup 48}Ti, {sup 49}Ti, {sup 53}Cr, and {sup 54}Cr nuclei were measured in the proton-energy range 7-11 MeV. The measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used, low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured data was performed withinmore » the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level density. The nuclear level densities for {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, and {sup 54}Mn were determined along with their energy dependences and model parameters. The results are discussed together with available experimental data and recommendations of model systematics.« less

Elevated Frequencies of Micronuclei and other Nuclear Abnormalities of Chrome Plating Workers Occupationally Exposed to Hexavalent Chromium.

PubMed

Sudha, S; Kripa, S K; Shibily, P; Shyn, J

2011-01-01

Biomonitoring provides a useful tool to estimate the genetic risk from exposure to genotoxic agents. The aim of this study was to assess the potential cytogenetic damage associated with occupational exposure to hexavalent chromium by using micronuclei (MN) as a biomarker. This was a cross-sectional study and all participants were males. Both the exposed and control individuals were selected from Coimbatore, Southern India. Exfoliated buccal cells from 44 chrome plating workers and 40 age and sex matched control subjects were examined for MN frequency and nuclear abnormalities (NA) other than micronuclei, such as binucleates, broken eggs, karyorrhexis, karyolysis and pyknosis. Results showed statistically significant difference between chrome plating workers and control groups. MN and NA frequencies in chrome plating workers were significantly higher than those in control groups (p < 0.05) and also significantly related to smoking habit (P < 0.05). A significant difference in NA was observed in workers exposed to chromium for longer duration. In addition to this, a higher degree of NA was observed among smokers. MN and other NA reflect genetic changes, events associated with carcinogenesis. Therefore the results of this study indicate that chrome plating workers are under risk of significant cytogenetic damage. Therefore, there is a need to educate those who work with heavy metals about the potential hazard of occupational exposure and the importance of using protective measures.

Urinary cyclophosphamide excretion and micronuclei frequencies in peripheral lymphocytes and in exfoliated buccal epithelial cells of nurses handling antineoplastics.

PubMed

Burgaz, S; Karahalil, B; Bayrak, P; Taşkin, L; Yavuzaslan, F; Bökesoy, I; Anzion, R B; Bos, R P; Platin, N

1999-02-02

In this study, urinary cyclophosphamide (CP) excretion rate, as well as micronuclei (MN) in peripheral lymphocytes and in buccal epithelial cells were determined for 26 nurses handling antineoplastics and 14 referents matched for age and sex. In urine samples of 20 out of 25 exposed nurses CP excretion rate was found in a range of 0.02-9.14 microg CP/24 h. Our results of the analyses of CP in urine demonstrates that when the nurses were handling CP (and other antineoplastic drugs) this particular compound was observed in urine. The mean values (+/-SD) of MN frequencies (%) in peripheral lymphocytes from the nurses and controls were 0.61 (+/-0. 32) and 0.28 (+/-0.16), respectively (p<0.01). The mean value (+/-SD) of MN frequency (%) in buccal epithelial cells of nurses was 0.16 (+/-0.19) and also mean MN frequency in buccal epithelial cells for controls was found to be as 0.08 (+/-0.08), (p>0.05). Age, sex and smoking habits have not influenced the parameters analyzed in this study. Handling time of antineoplastics, use of protective equipment and handling frequency of drugs have no effect on urinary and cytogenetic parameters analyzed. No correlation was found between the urinary CP excretion and the cytogenetic findings in nurses. Neither could we find any relationship between two cytogenetic endpoints. Our results have identified the possible genotoxic damage of oncology nurses related to occupational exposure to at least one antineoplastic agent, which is used as a marker for drug handling. As a whole, there is concern that the present handling practices of antineoplastic drugs used in the several hospitals in Ankara will not be sufficient to prevent exposure. Copyright 1999 Elsevier Science B.V.

Surface Selective Oxidation of Sn-Added CMnSi TRIP Steel

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Seo, Eun Jung; Jung, Geun Su; Suh, Dong Woo; De Cooman, Bruno C.

2016-04-01

The influence of the addition of Sn on the selective oxidation and the reactive wetting of CMnSi transformation-induced plasticity (TRIP) steels was studied by means of galvanizing simulator tests. A reference TRIP steel and TRIP steels containing Sn in the range of 0.05 to 1 wt pct were intercritically annealed at 1093 K (820 °C) in an N2+ 5 pct H2 gas atmosphere with a dew point of -60 °C. The thin-film oxides formed on the surface of the Sn-added CMnSi TRIP steel were investigated using transmission electron microscopy and 3-dimensional atom probe tomography. The addition of Sn (≥0.05 wt pct) changed the morphology of the xMnO·SiO2 surface oxides from a continuous film morphology to a lens-shaped island morphology. It also suppressed the formation of the Mn-rich oxides of MnO and 2MnO·SiO2. The changes in the morphology and chemistry of the surface oxides were clearly related to the surface segregation of Sn, which appeared to result in a decrease of the oxygen permeability at the surface. The formation of lens-shaped oxides improved the wettability of the CMnSi TRIP steel surface by the molten Zn. The improved wetting effect was attributed to an increased area fraction of the surface where the oxide layer was thinner. This enabled a direct, unhindered reaction between Fe and the Al in the liquid Zn and the formation of the inhibition layer in the initial stages of the hot dipping. The addition of a small amount of Sn was also found to decrease significantly the density of Zn-coating defects on CMnSi TRIP steel.

Electronic structure of the dilute magnetic semiconductor G a1 -xM nxP from hard x-ray photoelectron spectroscopy and angle-resolved photoemission

NASA Astrophysics Data System (ADS)

Keqi, A.; Gehlmann, M.; Conti, G.; Nemšák, S.; Rattanachata, A.; Minár, J.; Plucinski, L.; Rault, J. E.; Rueff, J. P.; Scarpulla, M.; Hategan, M.; Pálsson, G. K.; Conlon, C.; Eiteneer, D.; Saw, A. Y.; Gray, A. X.; Kobayashi, K.; Ueda, S.; Dubon, O. D.; Schneider, C. M.; Fadley, C. S.

2018-04-01

We have investigated the electronic structure of the dilute magnetic semiconductor (DMS) G a0.98M n0.02P and compared it to that of an undoped GaP reference sample, using hard x-ray photoelectron spectroscopy (HXPS) and hard x-ray angle-resolved photoemission spectroscopy (HARPES) at energies of about 3 keV. We present experimental data, as well as theoretical calculations, to understand the role of the Mn dopant in the emergence of ferromagnetism in this material. Both core-level spectra and angle-resolved or angle-integrated valence spectra are discussed. In particular, the HARPES experimental data are compared to free-electron final-state model calculations and to more accurate one-step photoemission theory. The experimental results show differences between G a0.98M n0.02P and GaP in both angle-resolved and angle-integrated valence spectra. The G a0.98M n0.02P bands are broadened due to the presence of Mn impurities that disturb the long-range translational order of the host GaP crystal. Mn-induced changes of the electronic structure are observed over the entire valence band range, including the presence of a distinct impurity band close to the valence-band maximum of the DMS. These experimental results are in good agreement with the one-step photoemission calculations and a prior HARPES study of G a0.97M n0.03As and GaAs [Gray et al., Nat. Mater. 11, 957 (2012), 10.1038/nmat3450], demonstrating the strong similarity between these two materials. The Mn 2 p and 3 s core-level spectra also reveal an essentially identical state in doping both GaAs and GaP.

Spinel, YbFe2O4, and Yb2Fe3O7 types of structure for compounds in the In2O3 and Sc2O3-A2O3-BO systems (A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, Cu, or Zn) at temperatures over 1000C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimizuka, N.; Mohri, T.

In the Sc2O3-Ga2O3-CuO, Sc2O3-Ga2O3-ZnO, and Sc2O3-Al2O3-CuO systems, ScGaCuO4, ScGaZnO4, and ScAlCuO4 with the YbFe2O4-type structure and Sc2Ga2CuO7 with the Yb2Fe3O7-type structure were obtained. In the In2O3-A2O3-BO systems (A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, or Zn), InGaFeO4, InGaNiO4, and InFeT MgO4 with the spinel structure, InGaZnO4, InGaMgO4, and InAl-CuO4 with the YbFe2O4-type structure, and In2Ga2MnO7 and In2Ga2ZnO7 with the Yb2Fe3O7-type structure were obtained. InGaMnO4 and InFe2O4 had both the YbFe2O4-type and spinel-type structures. The revised classification for the crystal structures of AB2O4 compounds is presented, based upon the coordination numbers of constituent A and B cations. 5more » references, 2 tables.« less

An unconventional origin of metal-ion rescue and inhibition in the Tetrahymena group I ribozyme reaction.

PubMed Central

Shan, S O; Herschlag, D

2000-01-01

The presence of catalytic metal ions in RNA active sites has often been inferred from metal-ion rescue of modified substrates and sometimes from inhibitory effects of alternative metal ions. Herein we report that, in the Tetrahymena group I ribozyme reaction, the deleterious effect of a thio substitution at the pro-Sp position of the reactive phosphoryl group is rescued by Mn2+. However, analysis of the reaction of this thio substrate and of substrates with other modifications strongly suggest that this rescue does not stem from a direct Mn2+ interaction with the Sp sulfur. Instead, the apparent rescue arises from a Mn2+ ion interacting with the residue immediately 3' of the cleavage site, A(+1), that stabilizes the tertiary interactions between the oligonucleotide substrate (S) and the active site. This metal site is referred to as site D herein. We also present evidence that a previously observed Ca2+ ion that inhibits the chemical step binds to metal site D. These and other observations suggest that, whereas the interactions of Mn2+ at site D are favorable for the chemical reaction, the Ca2+ at site D exerts its inhibitory effect by disrupting the alignment of the substrates within the active site. These results emphasize the vigilance necessary in the design and interpretation of metal-ion rescue and inhibition experiments. Conversely, in-depth mechanistic analysis of the effects of site-specific substrate modifications can allow the effects of specific metal ion-RNA interactions to be revealed and the properties of individual metal-ion sites to be probed, even within the sea of metal ions bound to RNA. PMID:10864040

Simultaneous quantification of 17 trace elements in blood by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) equipped with a high-efficiency sample introduction system.

PubMed

D'Ilio, S; Violante, N; Di Gregorio, M; Senofonte, O; Petrucci, F

2006-10-10

A quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) equipped with a dynamic reaction cell (DRC) and coupled with a desolvating nebulization system (APEX-IR) was employed to determine 17 elements (Al, As, Ba, Cd, Co, Cr, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, V, and Zr) in blood samples. Ammonia (for Al, Cr, Mn, and V) and O2 (for As and Se) were used as reacting gases. Selection of the best flow rate of the gases and optimization of the quadrupole dynamic bandpass tuning parameter (RPq) were carried out, using digested blood diluted 1+9 with deionized water and spiked with 1 microg L(-1) of Al, Cr, Mn, V and 5 microgL(-1) of As and Se. Detection limits were determined in digested blood using the 3sigma criterion. The desolvating system allowed a sufficient sensitivity to be achieved to determine elements at levels of ng L(-1) without detriment of signal stability. The accuracy of the method was tested with the whole blood certified reference material (CRM), certified for Al, As, Cd, Co, Cr, Mn, Mo, Ni, Pb, Sb, Se, and V, and with indicative values for Ba, Li, Sn, Sr, and Zr. The addition calibration approach was chosen for analysis. In order to confirm the DRC data, samples were also analyzed by means of sector field inductively coupled plasma mass spectrometry (SF-ICP-MS), operating in medium (m/Deltam=4000) and high (m/Deltam=10,000) resolution mode and achieving a good agreement between the two techniques.

Observation of new neutron-rich Mn, Fe, Co, Ni, and Cu isotopes in the vicinity of 78Ni

NASA Astrophysics Data System (ADS)

Sumikama, T.; Nishimura, S.; Baba, H.; Browne, F.; Doornenbal, P.; Fukuda, N.; Franchoo, S.; Gey, G.; Inabe, N.; Isobe, T.; John, P. R.; Jung, H. S.; Kameda, D.; Kubo, T.; Li, Z.; Lorusso, G.; Matea, I.; Matsui, K.; Morfouace, P.; Mengoni, D.; Napoli, D. R.; Niikura, M.; Nishibata, H.; Odahara, A.; Sahin, E.; Sakurai, H.; Söderström, P.-A.; Stefan, G. I.; Suzuki, D.; Suzuki, H.; Takeda, H.; Taniuchi, R.; Taprogge, J.; Vajta, Zs.; Watanabe, H.; Werner, V.; Wu, J.; Xu, Z. Y.; Yagi, A.; Yoshinaga, K.

2017-05-01

Neutron-rich nuclei in the vicinity of 78Ni were produced using a 238U beam at the RIKEN Radioactive Isotope Beam Factory. The particle-identification plot for the in-flight fission fragments highlights the first observation of eight new isotopes: 73Mn, 76Fe, Co,7877, 80,81,82Ni, and 83Cu. Although the β -decay half-lives of 77Co and 80Ni were recently reported by Xu et al. [Phys. Rev. Lett. 113, 032505 (2014)], 10.1103/PhysRevLett.113.032505 using data from the same experiment, the current work provides the first direct, quantitative evidence for the existence of these isotopes. The experimental production cross sections are reproduced in a satisfactory manner by theoretical predictions. An odd-even staggering of the cross sections was observed, and the effect appears to become more pronounced for the most exotic nuclei that were investigated. The staggering effect was interpreted as an increase of the neutron-evaporation probability for odd-N isotopes, owing to the decrease of the neutron-separation energy, Sn. The predicted cross section for 80Ni is significantly overestimated, which may be related to a weak binding of the neutron pair above the N =50 shell closure.

A Proposal of New Reference System for the Standard Axial, Sagittal, Coronal Planes of Brain Based on the Serially-Sectioned Images

PubMed Central

Park, Jin Seo; Park, Hyo Seok; Shin, Dong Sun; Har, Dong-Hwan; Cho, Zang-Hee; Kim, Young-Bo; Han, Jae-Yong; Chi, Je-Geun

2010-01-01

Sectional anatomy of human brain is useful to examine the diseased brain as well as normal brain. However, intracerebral reference points for the axial, sagittal, and coronal planes of brain have not been standardized in anatomical sections or radiological images. We made 2,343 serially-sectioned images of a cadaver head with 0.1 mm intervals, 0.1 mm pixel size, and 48 bit color and obtained axial, sagittal, and coronal images based on the proposed reference system. This reference system consists of one principal reference point and two ancillary reference points. The two ancillary reference points are the anterior commissure and the posterior commissure. And the principal reference point is the midpoint of two ancillary reference points. It resides in the center of whole brain. From the principal reference point, Cartesian coordinate of x, y, z could be made to be the standard axial, sagittal, and coronal planes. PMID:20052359

SEM observation on microbial like structure in the ferromanganese crust from the western Pacific Magellan Seamount

NASA Astrophysics Data System (ADS)

Yang, K.; Park, H.; Baik, H.; Kim, J.; Park, K. R.; Yoon, J.; Kim, J. W.

2016-12-01

Understanding the biogeochemical process in the Fe-Mn crust layer is important to reconstruct the paleo-environment when the Fe-Mn crust layer forms. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Electron Energy Loss Spectroscopy (EELS), and Polymerase Chain Reaction (PCR) were utilized to determine the redox states of Fe/Mn and microbial diversity at each layer. Samples were dredged from the western Pacific Magellan Seamount (OSM11) that consists of five well-defined layers from the rim (L1) to the core (L5). Some microbial like structures of sheath-like with filaments (L1 - L3), capsule-shaped (L2), fossilized coccolith mounds with phosphatized globules (L4), and bean-shaped (L4) were detected in entire layers. The cross sectional observation of bean-shaped microbe like structures encrusted with Fe-vernadite (L3) by Scanning Transmission Electron Microscopy (STEM) and Focused Ion Beam (FIB) technique revealed 1-μm diameter cavity in the center and porous structures of encrusting Fe-vernadite in periphery. Moreover, the organic carbon in the center cavity compared with inorganic C (from carbonate) in periphery was differentiated by C-K edge EELS spectra, suggesting that the microbe used to occupy. Indeed, the PCR analysis indicated the presence of functional gene (cumA; 1056bp & coxC; 810bp) association with Mn & Fe oxidizer that promote the formation of the crust. The cloning and sequencing of DNA PCR fragments revealed the appearance of geobacter species in L3 (G. sulfurreducens and G. lovleyi). The DNA molecular biological analysis and SEM direct observations suggest the evidence of biotic process in the formation of Fe-Mn crust.

75 FR 81176 - Drawbridge Operation Regulation; Rainey River, Rainer, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-27

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-1055] RIN 1625... January 26, 2011. ADDRESSES: You may submit comments identified by docket number USCG- 2010-1055 using any..., please include the docket number for this rulemaking (USCG-2010-1055), indicate the specific section of...

The Effect of Molar Preparation Axial Height on Retention of Adhesively-luted CAD/CAM Ceramic Crowns

DTIC Science & Technology

2015-04-29

IL, USA). The sectioned teeth were then mounted in autopolymerizing denture base methacrylate resin (Diamond D, Keystone Industries, Cherry Hill... Paul , MN, USA) was placed into the intaglio surface of the ceramic restoration. The restoration was then seated onto the tooth using digital finger

21 CFR 184.1446 - Manganese chloride.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese chloride. 184.1446 Section 184.1446 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1446 Manganese chloride. (a) Manganese chloride (MnCl2·4H2O, CAS...

11. Photographic copy of lines drawing of original construction (24 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Photographic copy of lines drawing of original construction (24 January 1911, in possession of St. Louis County Bridge Engineer, Virginia, Minnesota). Profile of main and approach spans; plan and sectional view of concrete river pier - Brosseau Road Bridge, County Road 694 spanning Cloquet at River, Burnett, St. Louis County, MN

78 FR 56229 - Ocean Transportation Intermediary License Revocations and Terminations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-12

... revoked or terminated for the reason shown pursuant to section 19 of the Shipping Act of 1984 (46 U.S.C.... Address: 19987 Commerce Parkway, Cleveland, OH 44130. Date Revoked: August 9, 2013. Reason: Failed to...., Suite C, Vadnais Heights, MN 55110. Date Revoked: July 29, 2013. Reason: Voluntary Surrender of License...

[Effect of the change in sulphate and dissolved oxygen mass concentration on metal release in old cast iron distribution pipes].

PubMed

Wu, Yong-li; Shi, Bao-you; Sun, Hui-fang; Zhang, Zhi-huan; Gu, Jun-nong; Wang, Dong-sheng

2013-09-01

To understand the processes of corrosion by-product release and the consequent "red water" problems caused by the variation of water chemical composition in drinking water distribution system, the effect of sulphate and dissolved oxygen (DO) concentration on total iron release in corroded old iron pipe sections historically transporting groundwater was investigated in laboratory using small-scale pipe section reactors. The release behaviors of some low-level metals, such as Mn, As, Cr, Cu, Zn and Ni, in the process of iron release were also monitored. The results showed that the total iron and Mn release increased significantly with the increase of sulphate concentration, and apparent red water occurred when sulphate concentration was above 400 mg x L(-1). With the increase of sulfate concentration, the effluent concentrations of As, Cr, Cu, Zn and Ni also increased obviously, however, the effluent concentrations of these metals were lower than the influent concentrations under most circumstances, which indicated that adsorption of these metals by pipe corrosion scales occurred. Increasing DO within a certain range could significantly inhibit the iron release.

Age-related differences in hair trace elements: a cross-sectional study in Orenburg, Russia.

PubMed

Skalnaya, Margarita G; Tinkov, Alexey A; Demidov, Vasily A; Serebryansky, Eugeny P; Nikonorov, Alexandr A; Skalny, Anatoly V

2016-09-01

Age-related differences in the trace element content of hair have been reported. However, some discrepancies in the data exist. The primary objective of this study was to estimate the change in hair trace elements content in relation to age. Six hundred and eighteen women and 438 men aged from 10-59 years took part in the current cross-sectional study. Hair Cr, Mn, Ni, Si, Al, As, Be, Cd and Pb tended to decrease with age in the female sample, whereas hair Cu, Fe, I, Se, Li and Sn were characterised by an age-associated increase. Hair levels of Cr, Cu, I, Mn, Ni, Si and Al in men decreased with age, whereas hair Co, Fe, Se, Cd, Li and Pb content tended to increase. Hair mercury increased in association with age in men and in women, whereas hair vanadium was characterised by a significant decrease in both sexes. The difference in hair trace element content between men and women decreased with age. These data suggest that age-related differences in trace element status may have a direct implication in the ageing process.

Multireversible redox processes in pentanuclear bis(triple-helical) manganese complexes featuring an oxo-centered triangular {Mn(II)2Mn(III)(μ3-O)}5+ or {Mn(II)Mn(III)2(μ3-O)}6+ core wrapped by two {Mn(II)2(bpp)3}-.

PubMed

Romain, Sophie; Rich, Jordi; Sens, Cristina; Stoll, Thibaut; Benet-Buchholz, Jordi; Llobet, Antoni; Rodriguez, Montserrat; Romero, Isabel; Clérac, Rodolphe; Mathonière, Corine; Duboc, Carole; Deronzier, Alain; Collomb, Marie-Noëlle

2011-09-05

A new pentanuclear bis(triple-helical) manganese complex has been isolated and characterized by X-ray diffraction in two oxidation states: [{Mn(II)(μ-bpp)(3)}(2)Mn(II)(2)Mn(III)(μ-O)](3+) (1(3+)) and [{Mn(II)(μ-bpp)(3)}(2)Mn(II)Mn(III)(2)(μ-O)](4+) (1(4+)). The structure consists of a central {Mn(3)(μ(3)-O)} core of Mn(II)(2)Mn(III) (1(3+)) or Mn(II)Mn(III)(2) ions (1(4+)) which is connected to two apical Mn(II) ions through six bpp(-) ligands. Both cations have a triple-stranded helicate configuration, and a pair of enantiomers is present in each crystal. The redox properties of 1(3+) have been investigated in CH(3)CN. A series of five distinct and reversible one-electron waves is observed in the -1.0 and +1.50 V potential range, assigned to the Mn(II)(4)Mn(III)/Mn(II)(5), Mn(II)(3)Mn(III)(2)/Mn(II)(4)Mn(III), Mn(II)(2)Mn(III)(3)/Mn(II)(3)Mn(III)(2), Mn(II)Mn(III)(4)/Mn(II)(2)Mn(III)(3), and Mn(III)(5)/Mn(II)Mn(III)(4) redox couples. The two first oxidation processes leading to Mn(II)(3)Mn(III)(2) (1(4+)) and Mn(II)(2)Mn(III)(3) (1(5+)) are related to the oxidation of the Mn(II) ions of the central core and the two higher oxidation waves, close in potential, are thus assigned to the oxidation of the two apical Mn(II) ions. The 1(4+) and 1(5+) oxidized species and the reduced Mn(4)(II) (1(2+)) species are quantitatively generated by bulk electrolyses demonstrating the high stability of the pentanuclear structure in four oxidation states (1(2+) to 1(5+)). The spectroscopic characteristics (X-band electron paramagnetic resonance, EPR, and UV-visible) of these species are also described as well as the magnetic properties of 1(3+) and 1(4+) in solid state. The powder X- and Q-band EPR signature of 1(3+) corresponds to an S = 5/2 spin state characterized by a small zero-field splitting parameter (|D| = 0.071 cm(-1)) attributed to the two apical Mn(II) ions. At 40 K, the magnetic behavior is consistent for 1(3+) with two apical S = 5/2 {Mn(II)(bpp)(3)}(-) and one S = 2 noninteracting spins (11.75 cm(3) K mol(-1)), and for 1(4+) with three S = 5/2 noninteracting spins (13.125 cm(3) K mol(-1)) suggesting that the {Mn(II)(2)Mn(III)(μ(3)-O)}(5+) and {Mn(II)Mn(III)(2)(μ(3)-O)}(6+) cores behave at low temperature like S = 2 and S = 5/2 spin centers, respectively. The thermal behavior below 40 K highlights the presence of intracomplex magnetic interactions between the two apical spins and the central core, which is antiferromagnetic for 1(3+) leading to an S(T) = 3 and ferromagnetic for 1(4+) giving thus an S(T) = 15/2 ground state.

Well-Covered Graphs: A Survey

DTIC Science & Technology

1991-01-01

critical G’s/# G’s -) 0 as IV(G)I -- oo? References [B1] C. Berge, Regularizable graphs, Ann. Discrete Math ., 3, 1978, 11-19. [B2] _ _, Some common...Springer-Verlag, Berlin, 1980, 108-123. [B3] _ _, Some common properties for regularizable graphs, edge-critical graphs, and B-graphs, Ann. Discrete Math ., 12...graphs - an extension of the K6nig-Egervgiry theorem, Discrete Math ., 27, 1979, 23-33. [ER] M.N Ellingham and G.F. Royle, Well-covered cubic graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uçar, Sevilay, E-mail: sevilayucar@maltepe.edu.tr; Kartal, Sehban; Armağan, Turgay

Structure factor S(q) and thermodynamic properties like entropy (S), isothermal compressibility (χ{sub T}), specific heat (C{sub V}) have been calculated for liquid 3d (Ti, V, Cr and Mn), 4d (Pd, Zr) and 5d (Pt) transition metals. In this work, we have used newly constructed Bretonnet-Silbert potential to describe electron-ion and ion-ion interaction using different reference systems. It is observed that our results are found to be in good agreement with experimental data as well as with other theoretical results.

High temperature phase chemistries and solidification mode prediction in nitrogen-strengthened austenitic stainless steels

NASA Astrophysics Data System (ADS)

Ritter, Ann M.; Henry, Michael F.; Savage, Warren F.

1984-07-01

Nitronic 50 and Nitronic 50W, two nitrogen-strengthened stainless steels, were heat treated over a wide range of temperatures, and the compositions of the ferrite and austenite at each temperature were measured with analytical electron microscopy techniques. The compositional data were used to generate the (γ + δ phase field on a 58 pct Fe vertical section. Volume fractions of ferrite and austenite were calculated from phase chemistries and compared with volume fractions determined from optical micrographs. Weld solidification modes were predicted by reference to the Cr and Ni contents of each alloy, and the results were compared with predictions based on the ratios of calculated Cr and Ni equivalents for the alloys. Nitronic 50, which contained ferrite and austenite at the solidus temperature of 1370 °C, solidified through the eutectic triangle, and the weld microstructure was similar to that of austenitic-ferritic solidification. Nitronic 50W was totally ferritic at 1340 °C and solidified as primary delta ferrite. During heat treatments, Nitronic 50 and Nitronic 50W precipitated secondary phases, notably Z-phase (NbCrN), sigma phase, and stringered phases rich in Mn and Cr.

Influence of heavy metal leaf contaminants on the in vitro growth of urban-tree phylloplane-fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, W.H.

1977-01-01

The surfaces of urban woody vegetation are contaminated with varying amounts of numerous metallic compounds, including Cd, Cu, Mn, Al, Cr, Ni, Fe, Pb, Na, and Zn. To examine the possibility that these metals may affect phylloplane fungi, the above cations were tested in vitro for their ability to influence the growth of numerous saprophytic and parasitic fungi isolated from the leaves of London plane trees. Considerable variation in growth inhibition by the metals was observed. Generally Aureobasidium pullulans, Epicoccum sp., and Phialophora verrucosa were relatively tolerant; Gnomonia platani, Cladsporium sp., and Pleurophomella sp. were intermediate; and Pestalotiopsis and Chaetomiummore » sp. were relatively sensitive to the incorporation of certain metals into solid and liquid media. If similar growth inhibitions occur in nature, competitive abilities or population structures of plant surface microbes may be altered by surface metal contamination. Metals causing the greatest and broadest spectrum growth suppression included Ni, Zn, Pb, Al, Fe, and Mn. 25 references, 4 figures.« less

A Hop-Sensitive Mechanism to Establish Route Optimization in Mobile Networks

NASA Astrophysics Data System (ADS)

Gnanaraj, J. Isac; Newton, P. Calduwel; Arockiam, L.; Kim, Tai-Hoon

The mobile network plays a vital role in mobile communications. It supports both host mobility and network mobility. The mobile network which supports network mobility can be called as NEMO. The NEMO refers to NEtwork MObility or mobile network that moves. Though NEMO provides many supports, it also suffers due to Quality of Service (QoS) issues. One such issue is Route Optimization (RO). When a Mobile Node (MN) is away from Home Network (HN), it will send a binding update to Home Agent (HA) in HN to inform its movement. If the Correspondent Node (CN) wants to send data to MN, it will send data through HA. In this scenario, three networks such as HN, Foreign Network (FN) and Correspondent Network are involved in data transfer. The involvement of these three networks affects the QoS. This paper concentrates on some of the QoS parameters to propose a QoS mechanism to establish RO among these three networks and significantly increases performance of the mobile network.

Heavy-metal pollution assessment in the coastal lagoons of Jacarepaguá, Rio de Janeiro, Brazil.

PubMed

Fernandes, H M; Bidone, E D; Veiga, L H; Patchineelam, S R

1994-01-01

The Jacarepaguá lagoon receives the waste from 239 industries and domestic sewage. Bottom sediment analysis revealed that metal pollution is not spread over the lagoons but restricted to the discharge areas of the main metal-carrier rivers. Metal concentrations in superficial water showed the following concentrations values in ng/ml: Zn, 9.63+/-3.59; Pb, 0.61+/-0.43; Cu, 0.94+/-0.45; Mn, 12.7+/-8.0. Metal concentration in fish (average of seven different species) presented the following results, in mg/kg wet weight: Cr, 0.08+/-0.01; Cu, 0.4+/-0.15; Zn, 4.6+/-3.4; Fe, 2.4+/-1.3; Mn, 0.4+/-0.3. These results imply, considering fish consumption rate and the RfD (USEPA Reference Dose), that the local population is not exposed to undue health risks. Metal concentrations in the water may, however, increase due to their dissolution induced by pH and redox changes in the sediments.

Elemental investigation of Syrian medicinal plants using PIXE analysis

NASA Astrophysics Data System (ADS)

Rihawy, M. S.; Bakraji, E. H.; Aref, S.; Shaban, R.

2010-09-01

Particle induced X-ray emission (PIXE) technique has been employed to perform elemental analysis of K, Ca, Mn, Fe, Cu, Zn, Br and Sr for Syrian medicinal plants used traditionally to enhance the body immunity. Plant samples were prepared in a simple dried base. The results were verified by comparing with those obtained from both IAEA-359 and IAEA-V10 reference materials. Relative standard deviations are mostly within ±5-10% suggest good precision. A correlation between the elemental content in each medicinal plant with its traditional remedial usage has been proposed. Both K and Ca are found to be the major elements in the samples. Fe, Mn and Zn have been detected in good levels in most of these plants clarifying their possible contribution to keep the body immune system in good condition. The contribution of the elements in these plants to the dietary recommended intakes (DRI) has been evaluated. Advantages and limitations of PIXE analytical technique in this investigation have been reviewed.

Mineral Composition of Wild and Cultivated Blueberries.

PubMed

Dróżdż, Paulina; Šėžienė, Vaida; Pyrzynska, Krystyna

2018-01-01

The concentrations of 13 elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn) were determined in several samples of native (wild) naturally growing and cultivated blueberry fruits. The total metal contents after mineralization were analyzed by inductively coupled plasma optical emission spectrometry. Reliability of the procedure was checked by the analysis of the certified reference materials Mixed Polish Herbs (INGT-MPH-2) and Leaves of Poplar (NCS DC 73350). In the fruits collected in the forest (wild blueberries), higher contents of Ca, Na, and Mg as well as Mn and Zn were observed. Similar levels of Cu, Cr, Fe, and Ni were detected in both wild-growing and cultivated plants. The significantly higher content of Fe and Cd in cultivated blueberries was connected with the content of these metals in soil samples collected from the same places. The metal extraction efficiency by hot water varied widely for the different blueberries (wild or cultivated) as well as their form (fresh or dried).

Process of prototyping coronary stents from biodegradable Fe-Mn alloys.

PubMed

Hermawan, Hendra; Mantovani, Diego

2013-11-01

Biodegradable stents are considered to be a recent innovation, and their feasibility and applicability have been proven in recent years. Research in this area has focused on materials development and biological studies, rather than on how to transform the developed biodegradable materials into the stent itself. Currently available stent technology, the laser cutting-based process, might be adapted to fabricate biodegradable stents. In this work, the fabrication, characterization and testing of biodegradable Fe-Mn stents are described. A standard process for fabricating and testing stainless steel 316L stents was referred to. The influence of process parameters on the physical, metallurgical and mechanical properties of the stents, and the quality of the produced stents, were investigated. It was found that some steps of the standard process such as laser cutting can be directly applied, but changes to parameters are needed for annealing, and alternatives are needed to replace electropolishing. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Tracking Metal Pollution in Lake Chapala: Concentrations in Water, Sediments, and Fish.

PubMed

Torres, Zaria; Mora, Miguel A; Taylor, Robert J; Alvarez-Bernal, Dioselina

2016-09-01

We measured concentrations of selected metals (Al, Ba, Cu, Mn, Hg, Sr, V, and Zn) in water, sediments, and fish from Lake Chapala and a reference site to evaluate potential negative effects on wildlife, particularly fish-eating birds. Fish metal concentrations ranged from 0.05 µg/g wet weight (ww) for Al and Cu to 64.70 µg/g ww for Sr. There was a positive and significant correlation between fish length and metals particularly for Ba, Cu, Mn, and Zn in Lake Chapala (p < 0.05). However, there were no significant correlations between metal concentrations and δ(15)N values in fish indicating no biomagnification through the food web. Overall, metal concentrations in water, sediments, and fish were similar to and in some cases below those reported for Lake Chapala over the last 20 years. Also, metal concentrations were below those that could be of concern for negative effects on fish and wildlife of Lake Chapala.

Mn(II) Oxidation by the Multicopper Oxidase Complex Mnx: A Coordinated Two-Stage Mn(II)/(III) and Mn(III)/(IV) Mechanism.

PubMed

Soldatova, Alexandra V; Romano, Christine A; Tao, Lizhi; Stich, Troy A; Casey, William H; Britt, R David; Tebo, Bradley M; Spiro, Thomas G

2017-08-23

The bacterial manganese oxidase MnxG of the Mnx protein complex is unique among multicopper oxidases (MCOs) in carrying out a two-electron metal oxidation, converting Mn(II) to MnO 2 nanoparticles. The reaction occurs in two stages: Mn(II) → Mn(III) and Mn(III) → MnO 2 . In a companion study , we show that the electron transfer from Mn(II) to the low-potential type 1 Cu of MnxG requires an activation step, likely forming a hydroxide bridge at a dinuclear Mn(II) site. Here we study the second oxidation step, using pyrophosphate (PP) as a Mn(III) trap. PP chelates Mn(III) produced by the enzyme and subsequently allows it to become a substrate for the second stage of the reaction. EPR spectroscopy confirms the presence of Mn(III) bound to the enzyme. The Mn(III) oxidation step does not involve direct electron transfer to the enzyme from Mn(III), which is shown by kinetic measurements to be excluded from the Mn(II) binding site. Instead, Mn(III) is proposed to disproportionate at an adjacent polynuclear site, thereby allowing indirect oxidation to Mn(IV) and recycling of Mn(II). PP plays a multifaceted role, slowing the reaction by complexing both Mn(II) and Mn(III) in solution, and also inhibiting catalysis, likely through binding at or near the active site. An overall mechanism for Mnx-catalyzed MnO 2 production from Mn(II) is presented.

The Megafaunal Communities of Mn-crusted Guyots in the Central and Western Pacific

NASA Astrophysics Data System (ADS)

Kelley, C.; France, S.; Gerringer, M.; Pomponi, S. A.; Amon, D.; Mundy, B.; Molodtsova, T.; Matsumoto, A. K.; Watling, L.; Baco-Taylor, A.

2016-12-01

The NOAA Office of Ocean Exploration and Research (OER) recently completed the second year of its 3 year CAPSTONE initiative to explore the deep waters of the U.S Pacific Monuments. At the preparation of this abstract, six ROV cruises were completed in the Papahanaumokuakea Marine National Monument (PMNM), the Mariana Trench Marine National Monument (MTMNM) and the Johnston Atoll unit of the Pacific Remote Islands Marine National Monument (PRIMNM). A seventh ROV cruise is scheduled for July 27 through August 9 in the Wake unit of PRIMNM. Manganese (Mn)-crusted guyots have been one of the priorities of these cruises. Sixteen guyots have been surveyed to date with 11 more targeted for the dives around Wake. A major science objective has been to gain a better understanding of the megafaunal communities on this type of seamount because interest is building in mining manganese crusts in the Central and Western Pacific, an area referred to as the Prime Crust Zone (PCZ). These surveys revealed the presence of unique animals and in some locations, high density communities of deepwater corals and sponges living on Mn crusts that could be severely impacted by deep sea mining operations. This presentation will summarize the initial findings from the surveys on all 27 guyots and will hopefully raise awareness of the need for cautious and responsible development of the deep sea mining industry.

Impact of metals in surface matrices from formal and informal electronic-waste recycling around Metro Manila, the Philippines, and intra-Asian comparison.

PubMed

Fujimori, Takashi; Takigami, Hidetaka; Agusa, Tetsuro; Eguchi, Akifumi; Bekki, Kanae; Yoshida, Aya; Terazono, Atsushi; Ballesteros, Florencio C

2012-06-30

We report concentrations, enrichment factors, and hazard indicators of 11 metals (Ag, As, Cd, Co, Cu, Fe, In, Mn, Ni, Pb, and Zn) in soil and dust surface matrices from formal and informal electronic waste (e-waste) recycling sites around Metro Manila, the Philippines, referring to soil guidelines and previous data from various e-waste recycling sites in Asia. Surface dust from e-waste recycling sites had higher levels of metal contamination than surface soil. Comparison of formal and informal e-waste recycling sites (hereafter, "formal" and "informal") revealed differences in specific contaminants. Formal dust contained a mixture of serious pollutant metals (Ni, Cu, Pb, and Zn) and Cd (polluted modestly), quite high enrichment metals (Ag and In), and crust-derived metals (As, Co, Fe, and Mn). For informal soil, concentration levels of specific metals (Cd, Co, Cu, Mn, Ni, Pb, and Zn) were similar among Asian recycling sites. Formal dust had significantly higher hazardous risk than the other matrices (p<0.005), excluding informal dust (p=0.059, almost significant difference). Thus, workers exposed to formal dust should protect themselves from hazardous toxic metals (Pb and Cu). There is also a high health risk for children ingesting surface matrices from informal e-waste recycling sites. Copyright © 2012 Elsevier B.V. All rights reserved.

Asymmetric carbon nanotube-MnO₂ two-ply yarn supercapacitors for wearable electronics.

PubMed

Su, Fenghua; Miao, Menghe

2014-04-04

Strong and flexible two-ply carbon nanotube yarn supercapacitors are electrical double layer capacitors that possess relatively low energy storage capacity. Pseudocapacitance metal oxides such as MnO₂ are well known for their high electrochemical performance and can be coated on carbon nanotube yarns to significantly improve the performance of two-ply carbon nanotube yarn supercapacitors. We produced a high performance asymmetric two-ply yarn supercapacitor from as-spun CNT yarn and CNT@Mn₂2 composite yarn in aqueous electrolyte. The as-spun CNT yarn serves as negative electrode and the CNT@MnO₂ composite yarn as positive electrode. This asymmetric architecture allows the operating potential window to be extended from 1.0 to 2.0 V and results in much higher energy and power densities than the reference symmetric two-ply yarn supercapacitors, reaching 42.0 Wh kg(-1) at a lower power density of 483.7 W kg(-1), and 28.02 Wh kg(-1) at a higher power density of 19,250 W kg(-1). The asymmetric supercapacitor can sustain cyclic charge-discharge and repeated folding/unfolding actions without suffering significant deterioration of specific capacitance. The combination of high strength, flexibility and electrochemical performance makes the asymmetric two-ply yarn supercapacitor a suitable power source for flexible electronic devices for applications that require high durability and wearer comfort.

Phytoextraction from mine spoils: insights from New Caledonia.

PubMed

Losfeld, Guillaume; Mathieu, Romain; L'Huillier, Laurent; Fogliani, Bruno; Jaffré, Tanguy; Grison, Claude

2015-04-01

Increasing pressure on mineral resources has drawn research efforts into innovative supply and recycling. Metal-rich biomass produced in phytoextraction recently proved an interesting starting material for green chemistry. It allows the production of new catalysts, referred to as ecocatalysts. Ecocatalysts provide increased yields in chemical production and increased regio- and chemo-selectivity, which result in high added value. This new approach to using metal-rich biomass could spur the development of phytoextraction, a technique considered promising for long, yet without credible economic outlets. In this regard, metallophyte biodiversity hotspots, such as New Caledonia, are of particular interest for biomass supply. Potential phytoextraction from mine spoils using two species endemic to New Caledonia is discussed here. Geissois pruinosa, a hypernickelophore, and Grevillea exul, a Mn accumulator, were selected for these original experiments. The results presented here 20 months after plantation of young trees from a nursery show the interest of the approach. Mean Ni concentrations of up to 1513 mg kg(-1) are reported in G. pruinosa, as well as 2000 mg kg(-1) Mn in G. exul. Concentrations of Ni and Mn in the leaves of each species appear to be correlated with leaf age. Plantation of these species may also ensure mine reclamation, and experiments were conducted with the principles of ecological restoration in mind adding a further dimension to the approach.

Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium, and lead in the liver and kidneys of dogs according to age, gender, and the occurrence of chronic kidney disease

PubMed Central

Mainzer, Barbara; Lahrssen-Wiederholt, Monika; Schafft, Helmut; Palavinskas, Richard; Breithaupt, Angele; Zentek, Jürgen

2015-01-01

This study was conducted to measure the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se), and lead (Pb) in canine liver, renal cortex, and renal medulla, and the association of these concentrations with age, gender, and occurrence of chronic kidney disease (CKD). Tissues from 50 dogs were analyzed using inductively coupled plasma mass spectrometry. Cu, Zn, and Mn levels were highest in the liver followed by the renal cortex and renal medulla. The highest Sr, Cd, and Se concentrations were measured in the renal cortex while lower levels were found in the renal medulla and liver. Female dogs had higher tissue concentrations of Sr (liver and renal medulla), Cd (liver), Zn (liver and renal cortex), Cr (liver, renal cortex, and renal medulla), and Pb (liver) than male animals. Except for Mn and Sb, age-dependent variations were observed for all element concentrations in the canine tissues. Hepatic Cd and Cr concentrations were higher in dogs with CKD. In conclusion, the present results provide new knowledge about the storage of specific elements in canine liver and kidneys, and can be considered important reference data for diagnostic methods and further investigations. PMID:25234328

49 CFR 385.4 - Matter incorporated by reference.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Matter incorporated by reference. 385.4 Section... FITNESS PROCEDURES General § 385.4 Matter incorporated by reference. (a) Incorporation by reference. Part 385 includes references to certain matter or materials, as listed in paragraph (b) of this section...

49 CFR 385.4 - Matter incorporated by reference.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Matter incorporated by reference. 385.4 Section... FITNESS PROCEDURES General § 385.4 Matter incorporated by reference. (a) Incorporation by reference. Part 385 includes references to certain matter or materials, as listed in paragraph (b) of this section...

Apparatus and method for solid fuel chemical looping combustion

DOEpatents

Siriwardane, Ranjani V; Weber, Justin M

2015-04-14

The disclosure provides an apparatus and method utilizing fuel reactor comprised of a fuel section, an oxygen carrier section, and a porous divider separating the fuel section and the oxygen carrier section. The porous divider allows fluid communication between the fuel section and the oxygen carrier section while preventing the migration of solids of a particular size. Maintaining particle segregation between the oxygen carrier section and the fuel section during solid fuel gasification and combustion processes allows gases generated in either section to participate in necessary reactions while greatly mitigating issues associated with mixture of the oxygen carrier with char or ash products. The apparatus and method may be utilized with an oxygen uncoupling oxygen carrier such as CuO, Mn.sub.3O.sub.4, or Co.sub.3O.sub.4, or utilized with a CO/H.sub.2 reducing oxygen carrier such as Fe.sub.2O.sub.3.

Homogeneity study of a corn flour laboratory reference material candidate for inorganic analysis.

PubMed

Dos Santos, Ana Maria Pinto; Dos Santos, Liz Oliveira; Brandao, Geovani Cardoso; Leao, Danilo Junqueira; Bernedo, Alfredo Victor Bellido; Lopes, Ricardo Tadeu; Lemos, Valfredo Azevedo

2015-07-01

In this work, a homogeneity study of a corn flour reference material candidate for inorganic analysis is presented. Seven kilograms of corn flour were used to prepare the material, which was distributed among 100 bottles. The elements Ca, K, Mg, P, Zn, Cu, Fe, Mn and Mo were quantified by inductively coupled plasma optical emission spectrometry (ICP OES) after acid digestion procedure. The method accuracy was confirmed by analyzing the rice flour certified reference material, NIST 1568a. All results were evaluated by analysis of variance (ANOVA) and principal component analysis (PCA). In the study, a sample mass of 400mg was established as the minimum mass required for analysis, according to the PCA. The between-bottle test was performed by analyzing 9 bottles of the material. Subsamples of a single bottle were analyzed for the within-bottle test. No significant differences were observed for the results obtained through the application of both statistical methods. This fact demonstrates that the material is homogeneous for use as a laboratory reference material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Manganese (Mn) Oxidation Increases Intracellular Mn in Pseudomonas putida GB-1

PubMed Central

Banh, Andy; Chavez, Valarie; Doi, Julia; Nguyen, Allison; Hernandez, Sophia; Ha, Vu; Jimenez, Peter; Espinoza, Fernanda; Johnson, Hope A.

2013-01-01

Bacterial manganese (Mn) oxidation plays an important role in the global biogeochemical cycling of Mn and other compounds, and the diversity and prevalence of Mn oxidizers have been well established. Despite many hypotheses of why these bacteria may oxidize Mn, the physiological reasons remain elusive. Intracellular Mn levels were determined for Pseudomonas putida GB-1 grown in the presence or absence of Mn by inductively coupled plasma mass spectrometry (ICP-MS). Mn oxidizing wild type P. putida GB-1 had higher intracellular Mn than non Mn oxidizing mutants grown under the same conditions. P. putida GB-1 had a 5 fold increase in intracellular Mn compared to the non Mn oxidizing mutant P. putida GB-1-007 and a 59 fold increase in intracellular Mn compared to P. putida GB-1 ∆2665 ∆2447. The intracellular Mn is primarily associated with the less than 3 kDa fraction, suggesting it is not bound to protein. Protein oxidation levels in Mn oxidizing and non oxidizing cultures were relatively similar, yet Mn oxidation did increase survival of P. putida GB-1 when oxidatively stressed. This study is the first to link Mn oxidation to Mn homeostasis and oxidative stress protection. PMID:24147089

Manganese accumulation in hair and teeth as a biomarker of manganese exposure and neurotoxicity in rats.

PubMed

Liang, Guiqiang; Zhang, Li'e; Ma, Shuyan; Lv, Yingnan; Qin, Huiyan; Huang, Xiaowei; Qing, Li; Li, Qin; Chen, Kangcheng; Xiong, Feng; Ma, Yifei; Nong, Jie; Yang, Xiaobo; Zou, Yunfeng

2016-06-01

Manganese (Mn) is an essential trace element to humans. However, excessive Mn causes cognitive impairment resulting from injury to the central nervous system within the hippocampus. No ideal biomarker is currently available for evaluating Mn exposure and associated neurotoxicity in the body. Hence, this study used Mn levels in the serum (MnS), teeth (MnT), and hair (MnH) as biomarkers for evaluating the association between Mn exposure and cognitive impairment in Mn-treated rats. A total of 32 male Sprague-Dawley rats were randomly divided into four groups, received 0, 5, 10, and 20 mg/(kg day) of MnCl2·4H2O for 5 days a week for 18 weeks, respectively. Lifetime Mn cumulative dose (LMCD) was used to evaluate external Mn exposure. Hippocampus, serum, teeth, and hair specimens were collected from the rats for Mn determination by graphite furnace atomic absorption spectrometry. Learning and memory functions were assessed using the Morris water maze test. Results showed that chronic Mn exposure increased the hippocampus (MnHip), MnS, MnT, and MnH levels, as well as impaired learning and memory function in rats. MnHip, MnT, and MnH levels were positively correlated with LMCD (r = 0.759, r = 0.925, and r = 0.908, respectively; p < 0.05), escape latency (r = 0.862, r = 0.716, and r = 0.814, respectively; p < 0.05), and the number of platform crossings (r = -0.734, r = -0.514, and r = -0.566, respectively; p < 0.05). No association was observed between MnS levels and the number of platform crossings (r = -0.286, p > 0.05). Thus, MnT and MnH detected long-term low-dose Mn exposure. These parameters can be reliable biomarkers for Mn exposure and associated neurotoxicity in Mn-treated rats.

Zn-Mn alloy coatings from acidic chloride bath: Effect of deposition conditions on the Zn-Mn electrodeposition-morphological and structural characterization

NASA Astrophysics Data System (ADS)

Loukil, N.; Feki, M.

2017-07-01

Zn-Mn alloy electrodeposition on steel electrode in chloride bath was investigated using cyclic voltammetric, chronopotentiometric and chronoamperometric techniques. Cyclic voltammetries (CV) reveal a deep understanding of electrochemical behaviors of each metal Zn, Mn, proton discharge and Zn-Mn co-deposition. The electrochemical results show that with increasing Mn2+ ions concentration in the electrolytic bath, Mn2+ reduction occurs at lower over-potential leading to an enhancement of Mn content into the Zn-Mn deposits. A dimensionless graph model was used to analyze the effect of Mn2+ ions concentration on Zn-Mn nucleation process. It was found that the nucleation process is not extremely affected by Mn2+ concentration. Nevertheless, it significantly depends on the applied potential. Several parameters such as Mn2+ ions concentration, current density and stirring were investigated with regard to the Mn content into the final Zn-Mn coatings. It was found that the Mn content increases with increasing the applied current density jimp and Mn2+ ions concentration in the electrolytic bath. However, stirring of the solution decreases the Mn content in the Zn-Mn coatings. The phase structure and surface morphology of Zn-Mn deposits are characterized by means of X-ray diffraction analysis and Scanning Electron Microscopy (SEM), respectively. The Zn-Mn deposited at low current density is tri-phasic and consisting of η-Zn, ζ-MnZn13 and hexagonal close packed ε-Zn-Mn. An increase in current density leads to a transition from crystalline to amorphous structure, arising from the hydroxide inclusions in the Zn-Mn coating at high current density.

Quantification of retinal pigment epithelial phenotypic variation using laser scanning cytometry.

PubMed

Hjelmeland, L M; Fujikawa, A; Oltjen, S L; Smit-McBride, Z; Braunschweig, D

2010-06-16

Quantifying phenotypic variation at the level of protein expression (variegation) within populations of retinal pigment epithelium (RPE) cells may be important in the study of pathologies associated with this variation. The lack of quantitative methods for examining single cells, however, and the variable presence of pigment and/or lipofuscin complicate this experimental goal. We have applied the technique of laser scanning cytometry (LSC) to paraffin sections of mouse and human eyes to evaluate the utility of LSC for these measurements. Mouse eyes were perfusion fixed in 4% paraformaldehyde and embedded in paraffin. Postmortem human eyes were fixed and dissected to obtain a 9-mm punch, which was then embedded in paraffin. A laser scanning cytometer equipped with violet, argon, and helium-neon lasers and the detectors for blue, green, and long red were used to record the fluorescence of each individual cell at all three wavelengths. Raw data were recorded and processed using the WinCyte software. Individual nuclei were identified by the fluorescence of the 4',6-diamidino-2-phenylindole (DAPI) nuclear counterstain. Next, RPE cells were uniquely identified in the green channel using an anti-retinal pigment epithelium-specific protein 65 kDa (anti-RPE65) monoclonal antibody with an Alexa Fluor 488-labeled secondary antibody. Mn-superoxide dismutase (MnSOD) was quantified in the long-red channel using an anti-MnSOD antibody and an Alexa Fluor 647-labeled secondary antibody. MnSOD(+) and RPE65(+) cells exhibited peaks in the plot of fluorescence intensity versus cell number, which could be characterized by the mean fluorescence intensity (MFI), the coefficient of variation (CV), and the percentage of total RPE cells that were also labeled for MnSOD. RPE cells can be uniquely identified in human and mouse paraffin sections by immunolabeling with anti-RPE65 antibody. A second antigen, such as MnSOD, can then be probed only within this set of RPE. Results are plotted primarily with the population frequency diagram, which can be subdivided into multiple regions. The data collected for each region include the MFI, the CV, and the number of cells that are immunolabeled in that region. Background interference from pigment or autofluorescent material can be successfully overcome by elevating the concentrations of fluorescent secondary antibodies. In the human and mouse eyes, age-related changes in MFI, CV, and percent RPE cells immunolabeled for MnSOD were observed. The extent of the variability of gene expression in RPE cells at the protein level can be quantified by LSC. Relative changes in the MFI, the CV, and/or percentage of RPE cells double labeled for a second antigen quantify the changes observed. The analysis of these data also suggest whether the effects observed are related to local changes in transcription (alterations of CV) or major changes of protein expression (MFI), which are likely to be due to changes in the chromatin structure. The changes of these variables with age suggest that the observed age-related variegation is primarily due to changes in the chromatin structure in individual cells.

Ion Mobility Measurements of Multianionic Metalloporphyrin Dimers: Structural Changes Induced by Countercation Exchange

NASA Astrophysics Data System (ADS)

Schneider, Erik; Brendle, Katrina; Jäger, Patrick; Weis, Patrick; Kappes, Manfred M.

2018-04-01

We present gas-phase structures of dimers of MnIII and FeIII meso-tetra(4-sulfonatophenyl)porphyrin multianions with various amounts of sodium and hydrogen counterions. The structural assignments are achieved by combining mass spectrometry, ion mobility measurements, quantum chemical calculations, and trajectory method collision cross section calculations. For a common charge state, we observe significant topological variations in the dimer structures of [(MTPPS)2+nX](6-n)- (M=MnIII, FeIII; X=H, Na; n = 1-3) induced by replacing hydrogen counterions by sodium. For sodium, the dimer structures are much more compact, a finding that can be rationalized by the stronger interactions of the sodium cations with the anionic sulfonic acid groups of the porphyrins as compared to hydrogen. [Figure not available: see fulltext.

RECENT REFERENCES: JULY 1, 2005 TO SEPTEMBER 30, 2005

DOE Office of Scientific and Technical Information (OSTI.GOV)

WINCHELL, D.F.

2005-09-30

This document lists experimental references added to Nuclear Science References (NSR) during the period July 1, 2005 to September 30, 2005. The first section lists keynumbers and keywords sorted by mass and nuclide. The second section lists all references, ordered by keynumber.

RECENT REFERENCES: OCTOBER 1, 2005 TO DECEMBER 31, 2005

DOE Office of Scientific and Technical Information (OSTI.GOV)

WINCHELL, D.F.

2005-12-31

This document lists experimental references added to Nuclear Science References (NSR) during the period October 1, 2005 to December 31, 2005. The first section lists keynumbers and keywords sorted by mass and nuclide. The second section lists all references, ordered by keynumber.

Correlation between structural, magnetic, and dielectric properties of manganese substituted cobalt ferrite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramana, C. V., E-mail: rvchintalapalle@utep.edu; Kolekar, Y. D.; Kamala Bharathi, K.

2013-11-14

Manganese (Mn) substituted cobalt ferrites (CoFe{sub 2−x}Mn{sub x}O{sub 4}, referred to CFMO) were synthesized and their structural, magnetic, and dielectric properties were evaluated. X-ray diffraction measurements coupled with Rietveld refinement indicate that the CFMO materials crystallize in the inverse cubic spinel phase. Temperature (T = 300 K and 10 K) dependent magnetization (M(H)) measurements indicate the long range ferromagnetic ordering in CoFe{sub 2−x}Mn{sub x}O{sub 4} (x = 0.00–0.15) ferrites. The cubic anisotropy constant (K{sub 1}(T)) and saturation magnetization (M{sub s}(T)) were derived by using the “law of approach” to saturation that describes the field dependence of M(H) for magnetic fields much higher than the coercive fieldmore » (H{sub c}). Saturation magnetization (M{sub s}), obtained from the model, decreases with increasing temperature. For CoFe{sub 2}O{sub 4}, M{sub s} decreases from 3.63 μ{sub B} per formula unit (f.u.) to 3.47 μ{sub B}/f.u. with increasing temperature from 10 to 300 K. CFMO (0.00–0.15) exhibit the similar trend while the magnitude of M{sub s} is dependent on Mn-concentration. M{sub s}-T functional relationship obeys the Bloch's law. The lattice parameter and magnetic moment calculated for CFMO reveals that Mn ions occupying the Fe and Co position at the octahedral site in the inverse cubic spinel phase. The structure and magnetism in CFMO are further corroborated by bond length and bond angle calculations. The dielectric constant dispersion of CFMO in the frequency range of 20 Hz–1 MHz fits to the modified Debye's function with more than one ion contributing to the relaxation. The relaxation time and spread factor derived from modeling the experimental data are ∼10{sup −4} s and ∼0.35(±0.05), respectively.« less

Utilizing a Key Aptamer Structure-Switching Mechanism for the Ultrahigh Frequency Detection of Cocaine.

PubMed

Neves, Miguel A D; Blaszykowski, Christophe; Thompson, Michael

2016-03-15

Aptasensing of small molecules remains a challenge as detection often requires the use of labels or signal amplification methodologies, resulting in both difficult-to-prepare sensor platforms and multistep, complex assays. Furthermore, many aptasensors rely on the binding mechanism or structural changes associated with target capture by the aptameric probe, resulting in a detection scheme customized to each aptamer. It is in this context that we report herein a sensitive cocaine aptasensor that offers both real-time and label-free measurement capabilities. Detection relies on the electromagnetic piezoelectric acoustic sensor (EMPAS) platform. The sensing interface consists of a S-(11-trichlorosilyl-undecanyl)benzenethiosulfonate (BTS) adlayer-coated quartz disc onto which a structure-switching cocaine aptamer (MN6) is immobilized, completing the preparation of the MN6 cocaine aptasensor (M6CA). The EMPAS system has recently been employed as the foundation of a cocaine aptasensor based on a structurally rigid cocaine aptamer variant (MN4), an aptasensor referred to by analogy as M4CA. M6CA represents a significant increase in terms of analytical performance, compared to not only M4CA but also other cocaine aptamer-based sensors that do not rely on signal amplification, producing an apparent K(d) of 27 ± 6 μM and a 0.3 μM detection limit. Remarkably, the latter is in the range of that achieved by cocaine aptasensors relying on signal amplification. Furthermore, M6CA proved to be capable not only of regaining its cocaine-binding ability via simple buffer flow over the sensing interface (i.e., without the necessity to implement an additional regeneration step, such as in the case of M4CA), but also of detecting cocaine in a multicomponent matrix possessing potentially assay-interfering species. Finally, through observation of the distinct shape of its response profiles to cocaine injection, demonstration was made that the EMPAS system in practice offers the possibility to distinguish between the binding mechanisms of structure-switching (MN6) vs rigid (MN4) aptameric probes, an ability that could allow the EMPAS to provide a more universal aptasensing platform than what is ordinarily observed in the literature.

Enhancement of efficiency by embedding ZnS and Mn-doped ZnS nanoparticles in P3HT:PCBM hybrid solid state solar cells

NASA Astrophysics Data System (ADS)

Jabeen, Uzma; Adhikari, Tham; Shah, Syed Mujtaba; Nunzi, Jean-Michel; Badshah, Amin; Ahmad, Iqbal

2017-06-01

Zinc sulphide (ZnS) and Mn-doped ZnS nanoparticles were synthesized by wet chemical method. The synthesized nanoparticles were characterized by UV-visible, fluorescence, X-ray diffraction (XRD), fourier transform infra-red (FTIR) spectrometer, field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). Scanning electron microscope (SEM) was used to find particle size while chemical composition of the synthesized materials was investigated by EDAX. UV-visible absorption spectrum of Mn-doped ZnS was slightly shifted to lower wavelength with respect to the un-doped zinc sulphide with decrease in the size of nanoparticles. Consequently, the band gap was tuned from 3.04 to 3.13 eV. The photoluminescence (PL) emission positioned at 597 nm was ascribed to 4T1 → 6A1 transition within the 3d shell of Mn2+. X-ray diffraction (XRD) analysis revealed that the synthesized nanomaterials existed in cubic crystalline state. The effect of embedding un-doped and doped ZnS nanoparticles in the active layer and changing the ratio of PCBM ([6, 6]-phenyl-C61-butyric acid methyl ester) to nanoparticles on the performance of hybrid solar cell was studied. The device with active layer consisting of poly(3-hexylthiophene) (P3HT), [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM), and un-doped ZnS nanoparticles combined in the ratio of (1:0.5:0.5) attained an efficiency of 2.42% which was found 71% higher than the reference device under the same conditions but not containing nanoparticles. Replacing ZnS nanoparticles with Mn-doped ZnS had a little effect on the enhancement of efficiency. The packing behavior and morphology of blend of nanoparticles with P3HT:PCBM were examined using atomic force microscope (AFM) and XRD. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al-5Mg-Mn Alloys Solidified Under Near-Rapid Cooling.

PubMed

Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

2016-01-29

Mn was an important alloying element used in Al-Mg-Mn alloys. However, it had to be limited to a low level (<1.0 wt %) to avoid the formation of coarse intermetallics. In order to take full advantage of the benefits of Mn, research was carried out to investigate the possibility of increasing the content of Mn by studying the effect of cooling rate on the formation of Fe- and Mn-rich intermetallics at different content levels of Mn and Fe. The results indicated that in Al-5Mg-Mn alloy with low Fe content (<0.1 wt %), intermetallic Al₆(Fe,Mn) was small in size and amount. With increasing Mn content, intermetallic Al₆(Fe,Mn) increased, but in limited amount. In high-Fe-containing Al-5Mg-Mn alloys (0.5 wt % Fe), intermetallic Al₆(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al₆(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al₆(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al₆(Fe,Mn) to become the primary phase at a lower Mn content.

[Chemical forms and ecological effect of soil Mn in liver cancer's high incidence area in Zhu-jiang River Delta, China].

PubMed

Dou, Lei; Zhou, Yong-Zhang; Li, Yong; Ma, Jin; An, Yan-Fei; Du, Hai-Yan; Li, Zhan-Qiang

2008-06-01

The samples of surface soil, deep soil, and vegetables were collected from the liver cancer's high- and low incidence areas in Zhujiang River Delta to study the relationships between soil Mn forms and vegetables' Mn enrichment. The results showed that the soil Mn in study area was mainly derived from parent materials, and rarely come from human activities. The average soil Mn content in liver cancer's high incidence area was 577.65 mg x kg(-1), being significantly lower than that of liver cancer's low incidence area (718.04 mg x kg(-1)) and whole country (710 mg x kg(-1)). The Mn forms in high incidence area were mainly of residual Mn and Fe-Mn oxide, and less of water soluble Mn and exchangeable Mn, with the sum of the latter two's distribution coefficients being not higher than 4%. In low incidence area, the distribution pattern of soil Mn forms was similar to that in high incidence area, but the absolute contents of the Mn forms were significantly higher. Soil total Mn and soil pH had significant effects on soil Mn forms. There existed significant positive correlations between soil total Mn and the Mn forms of Fe-Mn bound, humic acid bound, carbonate bound, and residual, and negative correlations between soil pH and soil water soluble and organic bound Mn forms. Among the test five kinds of vegetables, Youmai lettuce and Chinese cabbage in liver cancer' s high incidence area had a significantly lower Mn content than in low incidence area, while the other three had less difference. The Mn enrichment in test vegetables was positively correlated with to the content of soil available Mn (sum of water soluble Mn and exchangeable Mn), but had no correlations with the contents of soil total Mn and other Mn forms.

30. Photographic copy of historic construction drawing, ink on linen, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. Photographic copy of historic construction drawing, ink on linen, December 1889 (original filed in drawer 98, Bridge Division, Department of Public Works, St. Paul City Annex). Selby Avenue Bridge (truss spans): section of roadway with details. - Selby Avenue Bridge, Spanning Short Line Railways track at Selby Avenue between Hamline & Snelling Avenues, Saint Paul, Ramsey County, MN

75 FR 7031 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-16

... investigation resulting in-- (A) An affirmative determination of serious injury or threat thereof under section... Connection and Manpower, Vadnais Heights, MN, June 30, 2008. TA-W-71,807; B & C Machine Company, Barberton..., Northwest Division, Renton, WA, June 5, 2008. TA-W-71,258; UPM Raflatac, Inc., Leased Workers from Manpower...

78 FR 8587 - Thomson Reuters, Finance Operations & Technology Division, Including On-Site Leased Workers From...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-06

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-81,755] Thomson Reuters, Finance Operations & Technology Division, Including On-Site Leased Workers From Adecco; Eagan, MN; Amended Certification Regarding Eligibility To Apply for Worker Adjustment Assistance In accordance with Section 223 of the Trade Act of 1974, as amended (`...

Force Measurement Services at Kebs: AN Overview of Equipment, Procedures and Uncertainty

NASA Astrophysics Data System (ADS)

Bangi, J. O.; Maranga, S. M.; Nganga, S. P.; Mutuli, S. M.

This paper describes the facilities, instrumentation and procedures currently used in the force laboratory at the Kenya Bureau of Standards (KEBS) for force measurement services. The laboratory uses the Force Calibration Machine (FCM) to calibrate force-measuring instruments. The FCM derives its traceability via comparisons using reference transfer force transducers calibrated by the Force Standard Machines (FSM) of a National Metrology Institute (NMI). The force laboratory is accredited to ISO/IEC 17025 by the Germany Accreditation Body (DAkkS). The accredited measurement scope of the laboratory is 1 MN to calibrate force transducers in both compression and tension modes. ISO 376 procedures are used while calibrating force transducers. The KEBS reference transfer standards have capacities of 10, 50, 300 and 1000 kN to cover the full range of the FCM. The uncertainty in the forces measured by the FCM were reviewed and determined in accordance to the new EURAMET calibration guide. The relative expanded uncertainty of force W realized by FCM was evaluated in a range from 10 kN-1 MN, and was found to be 5.0 × 10-4 with the coverage factor k being equal to 2. The overall normalized error (En) of the comparison results was also found to be less than 1. The accredited Calibration and Measurement Capability (CMC) of the KEBS force laboratory was based on the results of those intercomparisons. The FCM enables KEBS to provide traceability for the calibration of class ‘1’ force instruments as per the ISO 376.

Validation of a dilute and shoot method for quantification of 12 elements by inductively coupled plasma tandem mass spectrometry in human milk and in cow milk preparations.

PubMed

Dubascoux, Stéphane; Andrey, Daniel; Vigo, Mario; Kastenmayer, Peter; Poitevin, Eric

2018-09-01

Nutritional information about human milk is essential as early human growth and development have been closely linked to the status and requirements of several macro- and micro-elements. However, methods addressing whole mineral profiling in human milk have been scarce due in part to their technical complexities to accurately and simultaneously measure the concentration of micro- and macro-trace elements in low volume of human milk. In the present study, a single laboratory validation has been performed using a "dilute and shoot" approach for the quantification of sodium (Na), magnesium (Mg), phosphorus (P), potassium (K), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo) and iodine (I), in both human milk and milk preparations. Performances in terms of limits of detection and quantification, of repeatability, reproducibility and trueness have been assessed and verified using various reference or certified materials. For certified human milk sample (NIST 1953), recoveries obtained for reference or spiked values are ranged from 93% to 108% (except for Mn at 151%). This robust method using new technology ICP-MS/MS without high pressure digestion is adapted to both routinely and rapidly analyze human milk micro-sample (i.e. less than 250 μL) in the frame of clinical trials but also to be extended to the mineral profiling of milk preparations like infant formula and adult nutritionals. Copyright © 2018 Elsevier GmbH. All rights reserved.

Comparing the Metal Concentration in the Hair of Cancer Patients and Healthy People Living in the Malwa Region of Punjab, India

PubMed Central

Blaurock-Busch, Eleonore; Busch, Yvette M.; Friedle, Albrecht; Buerner, Holger; Parkash, Chander; Kaur, Anudeep

2014-01-01

The cancer prevalence in the Malwa region of Punjab (1089/million/year) is much higher than the national average cancer prevalence in India (800/million/year). The participants in the present study were 50 healthy individuals and 49 cancer patients all living in the Malwa region of Punjab, with the healthy people being selected from the same household as the cancer patients. High concentrations of several potentially toxic elements were found in hair samples from people living in Punjab. Compared to standard reference ranges, the metals in excess in both the control and patient groups were aluminium (Al), barium (Ba), manganese (Mn), strontium (Sr) and uranium (U). The most significant findings were high lead (Pb), U and Ba concentrations. The maximum values for Ba, Mn, Pb and U were found in hair from breast cancer patients. The mean concentration of U in hair from the breast cancer patients was 0.63 μg U/g, which is more than double the value found in the control group and over six times higher than the reference range of 0.1 μg U/g. Water, soil, and phosphate fertilizers all seem to play a potential role, causing an increased metal burden in Punjabi people living in the Malwa region. The present study indicates that metals, and especially U, may be a factor in the development of breast cancer among Punjabi women. PMID:24453505

Synchrotron study of metal localization in Typha latifolia L. root sections

DOE PAGES

Qian, Yu; Jones, Keith W.; Feng, Huan; ...

2015-09-15

Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal-contaminated land. With the assistance of the synchrotron X-ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues of Typha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron-plaque-enriched dermal tissue and regular dermal tissue based on the spatial distribution ofmore » Pb and Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron-plaque-enriched dermal tissue, while significant (p < 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. Furthermore, the Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.« less

Elevated Frequencies of Micronuclei and other Nuclear Abnormalities of Chrome Plating Workers Occupationally Exposed to Hexavalent Chromium

PubMed Central

Sudha, S; Kripa, SK; Shibily, P; Shyn, J

2011-01-01

Background Biomonitoring provides a useful tool to estimate the genetic risk from exposure to genotoxic agents. The aim of this study was to assess the potential cytogenetic damage associated with occupational exposure to hexavalent chromium by using micronuclei (MN) as a biomarker. Methods This was a cross-sectional study and all participants were males. Both the exposed and control individuals were selected from Coimbatore, Southern India. Exfoliated buccal cells from 44 chrome plating workers and 40 age and sex matched control subjects were examined for MN frequency and nuclear abnormalities (NA) other than micronuclei, such as binucleates, broken eggs, karyorrhexis, karyolysis and pyknosis. Results Results showed statistically significant difference between chrome plating workers and control groups. MN and NA frequencies in chrome plating workers were significantly higher than those in control groups (p < 0.05) and also significantly related to smoking habit (P < 0.05). A significant difference in NA was observed in workers exposed to chromium for longer duration. In addition to this, a higher degree of NA was observed among smokers. Conclusion MN and other NA reflect genetic changes, events associated with carcinogenesis. Therefore the results of this study indicate that chrome plating workers are under risk of significant cytogenetic damage. Therefore, there is a need to educate those who work with heavy metals about the potential hazard of occupational exposure and the importance of using protective measures. PMID:26328050

Nano-sized Mn3O4 and β-MnOOH from the decomposition of β-cyclodextrin-Mn: 2. The water-oxidizing activities.

PubMed

Najafpour, Mohammad Mahdi; Mostafalu, Ramin; Hołyńska, Małgorzata; Ebrahimi, Foad; Kaboudin, Babak

2015-11-01

Nano-sized Mn oxides contain Mn3O4, β-MnOOH and Mn2O3 have been prepared by a previously reported method using thermal decomposition of β-cyclodextrin-Mn complexes. In the next step, the water-oxidizing activities of these Mn oxides using cerium(IV) ammonium nitrate as a chemical oxidant are studied. The turnover frequencies for β-MnO(OH) and Mn3O4 are 0.24 and 0.01-0.17 (mmol O2/mol Mns), respectively. Subsequently, water-oxidizing activities of these compounds are compared to the other previously reported Mn oxides. Important factors affecting water oxidation by these Mn oxides are also discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

30 CFR 250.198 - Documents incorporated by reference.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Addenda, and all Section I Interpretations Volume 55, incorporated by reference at § 250.803(b)(1), (b)(1...; July 1, 2005 Addenda, and all Section IV Interpretations Volume 55, incorporated by reference at § 250... Addenda, Divisions 1 and 2, and all Section VIII Interpretations Volumes 54 and 55, incorporated by...

Arsenite Oxidation by a Poorly-Crystalline Manganese Oxide 2. Results from X-ray Absorption Spectroscopy and X-ray Diffraction

PubMed Central

Lafferty, Brandon J.; Ginder-Vogel, Matthew; Zhu, Mengqiang; Livi, Kenneth J. T.; Sparks, Donald L.

2010-01-01

Arsenite (AsIII) oxidation by manganese oxides (Mn-oxides) serves to detoxify and, under many conditions, immobilize arsenic (As) by forming arsenate (AsV). AsIII oxidation by MnIV-oxides can be quite complex, involving many simultaneous forward reactions and subsequent back reactions. During AsIII oxidation by Mn-oxides, a reduction in oxidation rate is often observed, which is attributed to Mn-oxide surface passivation. X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) data show that MnII sorption on a poorly-crystalline hexagonal birnessite (δ-MnO2) is important in passivation early during reaction with AsIII. Also, it appears that MnIII in the δ-MnO2 structure is formed by conproportionation of sorbed MnII and MnIV in the mineral structure. The content of MnIII within the δ-MnO2 structure appears to increase as the reaction proceeds. Binding of AsV to δ-MnO2 also changes as MnIII becomes more prominent in the δ-MnO2 structure. The data presented indicate that AsIII oxidation and AsV sorption by poorly-crystalline δ-MnO2 is greatly affected by Mn oxidation state in the δ-MnO2 structure. PMID:20977204

Assessment of saliva, hair and toenails as biomarkers of low level exposure to manganese from drinking water in children.

PubMed

Ntihabose, Ruth; Surette, Céline; Foucher, Delphine; Clarisse, Olivier; Bouchard, Maryse F

2018-01-01

We evaluated hair, toenails, and saliva (whole and supernatant) as biomarkers of exposure to manganese (Mn) in 274 school age children (6-13 years) consuming well water in southeastern New Brunswick, Canada. Mn concentrations in tap water ranged from <0.03 to 1046μgL -1 (geometric mean 5.96μgL -1 ). The geometric mean of Mn intake resulting from the consumption of water was 0.25 (0-34.95) μg kg -1 day -1 . Both Mn concentration in water and Mn intake were significantly correlated with Mn in hair (r=0.60 and r=0.53, respectively), Mn in toenail (r=0.29 and r=0.37 respectively) and to a lesser extent with Mn in saliva supernatant (r=0.14 and r=0.18, respectively). Mn in whole saliva did not correlate with Mn in water or Mn intake. Both Mn in hair and Mn in toenail allowed to discriminate the most exposed group from the least exposed group, based on Mn in water and Mn intake from water. In this group of children with low level Mn exposure, Mn concentrations in hair, and toenails reflected reasonably well Mn exposure from drinking water, whereas Mn content in saliva correlated less strongly. Copyright © 2017 Elsevier B.V. All rights reserved.

Theoretical investigation of the reaction of Mn+ with ethylene oxide.

PubMed

Li, Yuanyuan; Guo, Wenyue; Zhao, Lianming; Liu, Zhaochun; Lu, Xiaoqing; Shan, Honghong

2012-01-12

The potential energy surfaces of Mn(+) reaction with ethylene oxide in both the septet and quintet states are investigated at the B3LYP/DZVP level of theory. The reaction paths leading to the products of MnO(+), MnO, MnCH(2)(+), MnCH(3), and MnH(+) are described in detail. Two types of encounter complexes of Mn(+) with ethylene oxide are formed because of attachments of the metal at different sites of ethylene oxide, i.e., the O atom and the CC bond. Mn(+) would insert into a C-O bond or the C-C bond of ethylene oxide to form two different intermediates prior to forming various products. MnO(+)/MnO and MnH(+) are formed in the C-O activation mechanism, while both C-O and C-C activations account for the MnCH(2)(+)/MnCH(3) formation. Products MnO(+), MnCH(2)(+), and MnH(+) could be formed adiabatically on the quintet surface, while formation of MnO and MnCH(3) is endothermic on the PESs with both spins. In agreement with the experimental observations, the excited state a(5)D is calculated to be more reactive than the ground state a(7)S. This theoretical work sheds new light on the experimental observations and provides fundamental understanding of the reaction mechanism of ethylene oxide with transition metal cations.

Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al–5Mg–Mn Alloys Solidified Under Near-Rapid Cooling

PubMed Central

Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

2016-01-01

Mn was an important alloying element used in Al–Mg–Mn alloys. However, it had to be limited to a low level (<1.0 wt %) to avoid the formation of coarse intermetallics. In order to take full advantage of the benefits of Mn, research was carried out to investigate the possibility of increasing the content of Mn by studying the effect of cooling rate on the formation of Fe- and Mn-rich intermetallics at different content levels of Mn and Fe. The results indicated that in Al–5Mg–Mn alloy with low Fe content (<0.1 wt %), intermetallic Al6(Fe,Mn) was small in size and amount. With increasing Mn content, intermetallic Al6(Fe,Mn) increased, but in limited amount. In high-Fe-containing Al–5Mg–Mn alloys (0.5 wt % Fe), intermetallic Al6(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al6(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al6(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al6(Fe,Mn) to become the primary phase at a lower Mn content. PMID:28787888

Synchrotron-Based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment.

PubMed

Blamey, F Pax C; Hernandez-Soriano, Maria C; Cheng, Miaomiao; Tang, Caixian; Paterson, David J; Lombi, Enzo; Wang, Wei Hong; Scheckel, Kirk G; Kopittke, Peter M

2015-11-01

Plant species differ in response to high available manganese (Mn), but the mechanisms of sensitivity and tolerance are poorly understood. In solution culture, greater than or equal to 30 µm Mn decreased the growth of soybean (Glycine max), but white lupin (Lupinus albus), narrow-leafed lupin (Lupin angustifolius), and sunflower (Helianthus annuus) grew well at 100 µm Mn. Differences in species' tolerance to high Mn could not be explained simply by differences in root, stem, or leaf Mn status, being 8.6, 17.1, 6.8, and 9.5 mmol kg(-1) leaf fresh mass at 100 µm Mn. Furthermore, x-ray absorption near edge structure analyses identified the predominance of Mn(II), bound mostly to malate or citrate, in roots and stems of all four species. Rather, differences in tolerance were due to variations in Mn distribution and speciation within leaves. In Mn-sensitive soybean, in situ analysis of fresh leaves using x-ray fluorescence microscopy combined with x-ray absorption near edge structure showed high Mn in the veins, and manganite [Mn(III)] accumulated in necrotic lesions apparently through low Mn sequestration in vacuoles or other vesicles. In the two lupin species, most Mn accumulated in vacuoles as either soluble Mn(II) malate or citrate. In sunflower, Mn was sequestered as manganite at the base of nonglandular trichomes. Hence, tolerance to high Mn was ascribed to effective sinks for Mn in leaves, as Mn(II) within vacuoles or through oxidation of Mn(II) to Mn(III) in trichomes. These two mechanisms prevented Mn accumulation in the cytoplasm and apoplast, thereby ensuring tolerance to high Mn in the root environment. © 2015 American Society of Plant Biologists. All Rights Reserved.

Synchrotron-Based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment1[OPEN

PubMed Central

Blamey, F. Pax C.; Hernandez-Soriano, Maria C.; Cheng, Miaomiao; Tang, Caixian; Paterson, David J.; Lombi, Enzo; Wang, Wei Hong; Scheckel, Kirk G.; Kopittke, Peter M.

2015-01-01

Plant species differ in response to high available manganese (Mn), but the mechanisms of sensitivity and tolerance are poorly understood. In solution culture, greater than or equal to 30 µm Mn decreased the growth of soybean (Glycine max), but white lupin (Lupinus albus), narrow-leafed lupin (Lupin angustifolius), and sunflower (Helianthus annuus) grew well at 100 µm Mn. Differences in species’ tolerance to high Mn could not be explained simply by differences in root, stem, or leaf Mn status, being 8.6, 17.1, 6.8, and 9.5 mmol kg–1 leaf fresh mass at 100 µm Mn. Furthermore, x-ray absorption near edge structure analyses identified the predominance of Mn(II), bound mostly to malate or citrate, in roots and stems of all four species. Rather, differences in tolerance were due to variations in Mn distribution and speciation within leaves. In Mn-sensitive soybean, in situ analysis of fresh leaves using x-ray fluorescence microscopy combined with x-ray absorption near edge structure showed high Mn in the veins, and manganite [Mn(III)] accumulated in necrotic lesions apparently through low Mn sequestration in vacuoles or other vesicles. In the two lupin species, most Mn accumulated in vacuoles as either soluble Mn(II) malate or citrate. In sunflower, Mn was sequestered as manganite at the base of nonglandular trichomes. Hence, tolerance to high Mn was ascribed to effective sinks for Mn in leaves, as Mn(II) within vacuoles or through oxidation of Mn(II) to Mn(III) in trichomes. These two mechanisms prevented Mn accumulation in the cytoplasm and apoplast, thereby ensuring tolerance to high Mn in the root environment. PMID:26395840

Dietary Manganese Modulates PCB126 Toxicity, Metal Status, and MnSOD in the Rat

PubMed Central

Wang, Bingxuan; Klaren, William D.; Wels, Brian R.; Simmons, Donald L.; Olivier, Alicia K.; Wang, Kai; Robertson, Larry W.; Ludewig, Gabriele

2016-01-01

PCB126 (3,3′,4,4′,5-pentachlorobiphenyl) is a potent aryl hydrocarbon receptor agonist and induces oxidative stress. Because liver manganese (Mn) levels decrease in response to PCB126, a Mn dietary study was designed to investigate the role of Mn in PCB126 toxicity. Male Sprague Dawley rats received diets containing 0, 10, or 150 ppm added Mn for 3 weeks, followed by a single ip injection of corn oil or PCB126 (5 µmol/kg body weight). After 2 weeks, Mn, Cu, Zn, and Fe levels in the heart, liver, and liver mitochondria, and Mn-containing superoxide dismutase (MnSOD) and metallothionein mRNA, MnSOD protein, and MnSOD activity were determined. Mn levels in liver, heart, and liver mitochondria were strongly decreased by the Mn-deficient diet. Small effects on Fe levels and a stepwise increase in MnSOD activity with dietary Mn were also visible. PCB126 caused profound changes in Cu (up), Zn, Fe, and Mn (down) in liver, but not in heart, and differing effects (Cu, Zn, and Fe up, Mn down) in liver mitochondria. Liver MnSOD and metallothionein mRNA levels and MnSOD protein were increased but MnSOD activity was decreased by PCB126. PCB126-induced liver enlargement was dose-dependently reduced with increasing dietary Mn. These changes in metals homeostasis and MnSOD activity in liver but not heart may be a/the mechanism of PCB126 liver-specific toxicity. Specifically, transport of Fenton metals (Cu, Fe) into and Mn out of the mitochondria, a probable mechanism for lower MnSOD activity, may be a/the cause of PCB126-induced oxidative stress. The role of metallothioneins needs further evaluation. Dietary Mn slightly alleviated PCB126-induced toxicities. PMID:26660635

Structural response of phyllomanganates to wet aging and aqueous Mn(II)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinkle, Margaret A. G.; Flynn, Elaine D.; Catalano, Jeffrey G.

Naturally occurring Mn(IV/III) oxides are often formed through microbial Mn(II) oxidation, resulting in reactive phyllomanganates with varying Mn(IV), Mn(III), and vacancy contents. Residual aqueous Mn(II) may adsorb in the interlayer of phyllomanganates above vacancies in their octahedral sheets. The potential for interlayer Mn(II)-layer Mn(IV) comproportionation reactions and subsequent formation of structural Mn(III) suggests that aqueous Mn(II) may cause phyllomanganate structural changes that alters mineral reactivity or trace metal scavenging. Here we examine the effects of aging phyllomanganates with varying initial vacancy and Mn(III) content in the presence and absence of dissolved Mn(II) at pH 4 and 7. Three phyllomanganates weremore » studied: two exhibiting turbostratic layer stacking (δ-MnO2 with high vacancy content and hexagonal birnessite with both vacancies and Mn(III) substitutions) and one with rotationally ordered layer stacking (triclinic birnessite containing predominantly Mn(III) substitutions). Structural analyses suggest that during aging at pH 4, Mn(II) adsorbs above vacancies and promotes the formation of phyllomanganates with rotationally ordered sheets and mixed symmetries arranged into supercells, while structural Mn(III) undergoes disproportionation. These structural changes at pH 4 correlate with reduced Mn(II) uptake onto triclinic and hexagonal birnessite after 25 days relative to 48 h of reaction, indicating that phyllomanganate reactivity decreases upon aging with Mn(II), or that recrystallization processes involving Mn(II) uptake occur over 25 days. At pH 7, Mn(II) adsorbs and causes limited structural effects, primarily increasing sheet stacking in δ-MnO2. These results show that aging-induced structural changes in phyllomanganates are affected by aqueous Mn(II), pH, and initial solid-phase Mn(III) content. In conclusion, such restructuring likely alters manganese oxide reactions with other constituents in environmental and geologic systems, particularly trace metals and redox-active compounds.« less

A Comparison of Two Yeast MnSODs: Mitochondrial Saccharomyces cerevisiae versus Cytosolic Candida albicans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng Y.; Cabelli D.; Stich, T.A.

Human MnSOD is significantly more product-inhibited than bacterial MnSODs at high concentrations of superoxide (O{sub 2}{sup -}). This behavior limits the amount of H{sub 2}O{sub 2} produced at high [O{sub 2}{sup -}]; its desirability can be explained by the multiple roles of H{sub 2}O{sub 2} in mammalian cells, particularly its role in signaling. To investigate the mechanism of product inhibition in MnSOD, two yeast MnSODs, one from Saccharomyces cerevisiae mitochondria (ScMnSOD) and the other from Candida albicans cytosol (CaMnSODc), were isolated and characterized. ScMnSOD and CaMnSODc are similar in catalytic kinetics, spectroscopy, and redox chemistry, and they both rest predominantlymore » in the reduced state (unlike most other MnSODs). At high [O{sub 2}{sup -}], the dismutation efficiencies of the yeast MnSODs surpass those of human and bacterial MnSODs, due to very low level of product inhibition. Optical and parallel-mode electron paramagnetic resonance (EPR) spectra suggest the presence of two Mn{sup 3+} species in yeast Mn{sup 3+}SODs, including the well-characterized 5-coordinate Mn{sup 3+} species and a 6-coordinate L-Mn{sup 3+} species with hydroxide as the putative sixth ligand (L). The first and second coordination spheres of ScMnSOD are more similar to bacterial than to human MnSOD. Gln154, an H-bond donor to the Mn-coordinated solvent molecule, is slightly further away from Mn in yeast MnSODs, which may result in their unusual resting state. Mechanistically, the high efficiency of yeast MnSODs could be ascribed to putative translocation of an outer-sphere solvent molecule, which could destabilize the inhibited complex and enhance proton transfer from protein to peroxide. Our studies on yeast MnSODs indicate the unique nature of human MnSOD in that it predominantly undergoes the inhibited pathway at high [O{sub 2}{sup -}].« less

A Comparison of Two Yeast MnSODs: Mitochondrial Saccharomyces cerevisiae versus Cytosolic Candida albicans

PubMed Central

Sheng, Yuewei; Stich, Troy A.; Barnese, Kevin; Gralla, Edith B.; Cascio, Duilio; Britt, R. David; Cabelli, Diane E.; Valentine, Joan Selverstone

2011-01-01

Human MnSOD is significantly more product-inhibited than bacterial MnSODs at high concentrations of superoxide (O2−). This behavior limits the amount of H2O2 produced at high [O2−]; its desirability can be explained by the multiple roles of H2O2 in mammalian cells, particularly its role in signaling. To investigate the mechanism of product inhibition in MnSOD, two yeast MnSODs, one from Saccharomyces cerevisiae mitochondria (ScMnSOD) and the other from Candida albicans cytosol (CaMnSODc), were isolated and characterized. ScMnSOD and CaMnSODc are similar in catalytic kinetics, spectroscopy and redox chemistry, and they both rest predominantly in the reduced state (unlike most other MnSODs). At high [O2−] the dismutation efficiencies of the yeast MnSODs surpass those of human and bacterial MnSODs, due to very low level of product inhibition. Optical and parallel-mode electron paramagnetic resonance (EPR) spectra suggest the presence of two Mn3+ species in yeast Mn3+SODs, including the well-characterized 5-coordinate Mn3+ species and a 6-coordinate L-Mn3+ species with hydroxide as the putative sixth ligand (L). The first and second coordination spheres of ScMnSOD are more similar to bacterial than to human MnSOD. Gln154, an H-bond donor to the Mn-coordinated solvent molecule, is slightly further away from Mn in yeast MnSODs, which may result in their unusual resting state. Mechanistically, the high efficiency of yeast MnSODs could be ascribed to putative translocation of an outer-sphere solvent molecule, which could destabilize the inhibited complex and enhance proton transfer from protein to peroxide. Our studies on yeast MnSODs indicate the unique nature of human MnSOD in that it predominantly undergoes the inhibited pathway at high [O2−]. PMID:22077216

Structural response of phyllomanganates to wet aging and aqueous Mn(II)

DOE PAGES

Hinkle, Margaret A. G.; Flynn, Elaine D.; Catalano, Jeffrey G.

2016-08-06

Naturally occurring Mn(IV/III) oxides are often formed through microbial Mn(II) oxidation, resulting in reactive phyllomanganates with varying Mn(IV), Mn(III), and vacancy contents. Residual aqueous Mn(II) may adsorb in the interlayer of phyllomanganates above vacancies in their octahedral sheets. The potential for interlayer Mn(II)-layer Mn(IV) comproportionation reactions and subsequent formation of structural Mn(III) suggests that aqueous Mn(II) may cause phyllomanganate structural changes that alters mineral reactivity or trace metal scavenging. Here we examine the effects of aging phyllomanganates with varying initial vacancy and Mn(III) content in the presence and absence of dissolved Mn(II) at pH 4 and 7. Three phyllomanganates weremore » studied: two exhibiting turbostratic layer stacking (δ-MnO2 with high vacancy content and hexagonal birnessite with both vacancies and Mn(III) substitutions) and one with rotationally ordered layer stacking (triclinic birnessite containing predominantly Mn(III) substitutions). Structural analyses suggest that during aging at pH 4, Mn(II) adsorbs above vacancies and promotes the formation of phyllomanganates with rotationally ordered sheets and mixed symmetries arranged into supercells, while structural Mn(III) undergoes disproportionation. These structural changes at pH 4 correlate with reduced Mn(II) uptake onto triclinic and hexagonal birnessite after 25 days relative to 48 h of reaction, indicating that phyllomanganate reactivity decreases upon aging with Mn(II), or that recrystallization processes involving Mn(II) uptake occur over 25 days. At pH 7, Mn(II) adsorbs and causes limited structural effects, primarily increasing sheet stacking in δ-MnO2. These results show that aging-induced structural changes in phyllomanganates are affected by aqueous Mn(II), pH, and initial solid-phase Mn(III) content. In conclusion, such restructuring likely alters manganese oxide reactions with other constituents in environmental and geologic systems, particularly trace metals and redox-active compounds.« less

The X-Ray Spectra of Blazars: Analysis of the Complete EXOSAT Archive: Erratum

NASA Astrophysics Data System (ADS)

Sambruna, Rita M.; Barr, Paul; Giommi, Paolo; Maraschi, Laura; Tagliaferri, Gianpiero; Treves, Aldo

1995-07-01

In the paper "The X-Ray Spectra of Blazars: Analysis of the Complete EXOSAT Archive" by Rita M. Sambruna, Paul Barr, Paolo Giommi, Laura Maraschi, Gianpiero Tagliaferri, and Aldo Treves (ApJS, 95,371 [1994]), the section regarding the object PKS 1510-08 (Section 4.4.14) contains an erroneous quotation. K. P. Singh, A.R. Rao, and M.N. Vahia (ApJ, 365,455 [1990]) in fact detected: emission line only in the 1984 data, and not in the 1985 spectrum, as stated.

Reducing mineral usage in feedlot diets for Nellore cattle: II. Impacts of calcium, phosphorus, copper, manganese, and zinc contents on intake, performance, and liver and bone status.

PubMed

Prados, L F; Sathler, D F T; Silva, B C; Zanetti, D; Valadares Filho, S C; Alhadas, H M; Detmann, E; Santos, S A; Mariz, L D S; Chizzotti, M L

2017-04-01

Weaned Nellore bulls ( = 36; 274 ± 34 kg) were used in a randomized block design with a 2 × 2 factorial arrangement of treatments to evaluate intake, fecal excretion, and performance with different concentrations of minerals. Experimental diets were formulated with 2 concentrations of Ca and P (macromineral factor; diet supplying 100% of Ca and P according to BR-CORTE () [CaP+] or diet without limestone and dicalcium phosphate [CaP-]) and 2 concentrations of microminerals (micromineral factor; diet with supplementation of microminerals [Zn, Mn, and Cu; CuMnZn+] or diet without supplementation of microminerals [Zn, Mn, and Cu; CuMnZn-]). The factor CaP- was formulated without the addition of limestone and dicalcium phosphate, and the factor CuMnZn- was formulated without inorganic supplementation of microminerals (premix). The diets were isonitrogenous (13.3% CP). Intake was individually monitored every day. Indigestible NDF was used as an internal marker for digestibility estimates. The bulls were slaughtered (84 or 147 d on feed), and then carcass characteristics were measured and liver and rib samples were collected. Feed, feces, rib bones, and liver samples were analyzed for DM, ash, CP, ether extract (EE), Ca, P, Zn, Mn, and Cu. There were no significant interactions ( ≥ 0.06) between macro- and micromineral supplementation for any variables in the study. Calcium, P, and micromineral concentrations did not affect ( ≥ 0.20) intake of DM, OM, NDF, EE, CP, TDN, and nonfiber carbohydrates (NFC). Calcium and P intake were affected ( < 0.01) by macromineral factor. Animals fed without Ca and P supplementation consumed less of these minerals. Dry matter and nutrient fecal excretion (OM, NDF, EE, CP, and NFC) were similar ( ≥ 0.23) among all factors. Performance and carcass characteristics were similar ( ≥ 0.09) among diets. The content of ash in rib bones was not affected by diets ( ≥ 0.06). Plasma P and phosphatase alkaline concentrations were similar ( ≥ 0.52) among diets. Supplementation of microminerals decreased ( < 0.01) plasma Ca concentration; nevertheless, all analyzed blood metabolites were within the reference values. Supplementation of Ca and P increased ( < 0.01) fecal excretion of these minerals. These results indicate that mineral supplementation (Ca, P, Zn, Mn, and Cu) of conventional feedlot diets for Nellore bulls may be not necessary. Dietary reductions in these minerals would represent a decrease in the cost of feedlot diets. Dietary reduction in Ca and P content cause a decrease in fecal excretion of these minerals, which, in turn, represents an opportunity to reduce the environmental impact of feedlot operations.

Magnetic and electrical properties of several Mn-based amorphous alloys

NASA Astrophysics Data System (ADS)

Obi, Y.; Morita, H.; Fujimori, H.

1987-03-01

Magnetic and electrical properties of amorphous Mn-Y, Mn-Zr, and Mn-Nb alloys have been investigated. All these alloys have a temperature-dependent susceptibility which is well fitted by a Curie-Weiss law. This implies the existence of localized magnetic moments associated with the Mn atoms. In addition, amorphous Mn-Y alloys exhibit spin-glass characteristics at low temperature. The experimental results of the electrical resistivity show that the temperature coefficient of resistivity (TCR) of both Mn-Y and Mn-Zr are negative, while Mn-Nb has a positive TCR. On the other hand, the resistivity-temperature curves of Mn-Zr and Mn-Nb have nearly the same tendency but are different from that of Mn-Y.

Maastrichtian sedimentation and palaeoenvironments of the Saratov Volga region

NASA Astrophysics Data System (ADS)

Iakovishina, Elena; Blinova, Irina; Kopaevich, Ludmila; Vishnevskaya, Valentina; Bordunov, Sergey

2016-04-01

The Saratov Volga region was a shallow-marine epicontinental basin North-Eastern shelf zone of the Tethys Ocean in the Maastrichtian. The basis for the modeling conditions of sedimentation was the detection mineral composition of rocks, as well as the contents of various chemical elements in rocks in three reference sections: Lower Bannovka, quarries "Bolshevik" and "Kommunar". Rocks of quarries "Bolshevik" and "Kommunar" characterized by quartz-calcite mineral association. The main rock-forming mineral is calcite, small amounts in rocks contain quartz. Other mineral composition characterized section Lower Bannovka. At the base of the section in the rock marked the presence of the opal. The source of silica are radiolarians. Favorable conditions for the existence of which is cold deep water enriched with SiO2. Above the section marked authigenic glauconite, which are confined to zones of skip in sedimentation.Further up begins to dominate the accumulation of calcite with rich bentic foraminifera. Clay minerals in rocks of the section Lower Bannovka presented montmorillonite and illite. The relationship of chemical elements and their alkali modules allow to detail the conditions of sedimentation. The ratio of Fe/Mn in them varies from 44 to 5729. Higher values are characteristic of glauconite sandstones. Up the section marked decrease in the Ti/Zr, indicating that the increase in the distance from the source area to the place of deposition. The similarity values of the ratio Ti/Zr samples indicates a community source area. Sedimentation Model revealed the impact of the PreUral strait connecting Tethys and Paleoarktic. Through the Strait of deep cold water saturated with SiO2, penetrated into the of the Saratov Volga region, were accumulated clay. The closing of the PreUral Strait changed the conditions of sedimentation, the associated fall in sea levels due to global cooling reflected in the crisis of radiolarians, increase in the number of glauconite. Subsequent warming and warm-water transgression caused dominance of carbonates. The work was supported by grants 15-05-04990, 15-05-04700 Russian Foundation for Basic Research and IGCP project 609.

Creation of a 3Mn/1Fe cluster in the oxygen-evolving complex of photosystem II and investigation of its functional activity.

PubMed

Semin, B К; Davletshina, L N; Seibert, M; Rubin, A B

2018-01-01

Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H 2 Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH5.7) than at neutral pH (3Mn/RC are extracted at pH6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]. Here we investigated the efficiency of Mn extraction by Fe(II) at acidic pH and found that Fe(II) cations can extract only 1Mn/RC from PSII(-Ca,4Mn) membranes at pH 5.7, forming a 3Mn/1Fe cluster. Also we found that the presence of Fe cations in a heteronuclear cluster (2Mn/2Fe) increases the resistance of the remaining Mn cations to H 2 Q action, since H 2 Q can extract Mn cations from homonuclear Mn clusters of PSII(-Ca,4Mn) and PSII(-Ca,2Mn) membranes but not from the heteronuclear cluster in PSII(-Ca,2Mn,2Fe) membranes. H 2 Q also cannot extract Mn from PSII membranes obtained by incubation of PSII(-Ca,4Mn) membranes with Fe(II) cations at pH5.7, which suggests the formation of a heteronuclear 3Mn/1Fe cluster in the OEC. Functional activity of PSII with a 3Mn/1Fe cluster was investigated. PSII preparations with a 3Mn/1Fe cluster in the OEC are able to photoreduce the exogenous electron acceptor 2,6-dichlorophenolindophenol, possibly due to incomplete oxidation of water molecules as is the case with PSII(-Ca,2Mn,2Fe) samples. However, in the contrast to PSII(-Ca,2Mn,2Fe) samples PSII(-Ca,3Mn,1Fe) membranes can evolve O 2 at a low rate in the presence of exogenous Ca 2+ (at about 27% of the rate of O 2 evolution in native PSII membranes). The explanation for this phenomenon (either water splitting and production of molecular O 2 by the 3Mn/1Fe cluster or apparent O 2 evolution due to minor contamination of PSII(3Mn,1Fe) samples with PSII(-Ca,4Mn) membranes) is discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Manganese in plasma: a promising biomarker of exposure to Mn in welders. A pilot study.

PubMed

Hoet, Perrine; Vanmarcke, Els; Geens, Tom; Deumer, Gladys; Haufroid, Vincent; Roels, Harry A

2012-08-13

There is raising concern about the potential neurotoxic effects of manganese (Mn) inhalation exposure in welders. Because most of the airborne particles in welding fume are in the respirable fraction, their bioavailability is likely to be higher than for coarser dust exposure. No well-validated biomarker for Mn exposure is available. To investigate the interest of measuring Mn in plasma (Mn-P) and urine (Mn-U) as biomarkers of exposure in a group of 28 welders whose tasks were only welding-related. Ambient air exposure to Mn (Mn-air) was determined by personal full-shift measurements on Monday and Tuesday. On the same days, blood and urine samples were collected before and after the shift. Mn-air varied from 1.3 to 729 μg/m(3) (GM 27.7). For Mn-U 65% of the values in welders were below the LOQ (0.20 μg/L). Compared to controls, the welders' Mn-P averaged 33% higher (1.5 vs 2.0 μg/L). In welders, the after-shift Mn-P values correlated well with Mn-air above 10 μg/m(3). In spite of similar Mn-air exposure on Monday and Tuesday, the relationships between Mn-air and after-shift Mn-P strikingly differed on Tuesday in that the inflection in the relationship was less obvious and the slope of the regression line (Mn-P after-shift/logMn-air) for a doubling of logMn-air was 2.3 times lower than on Monday. On Monday (the first day of the workweek), a Mn-P value of 2 μg/L could distinguish Mn-air exposure above or below 20 μg/m(3) with a sensitivity of 69% and a specificity of 82%. This preliminary study indicates that Mn-P is a promising biomarker of current exposure to Mn in welders and lends biological plausibility to the intended change for the Mn TLV-TWA of 20 μg/m(3) proposed by ACGIH for respirable Mn particulate. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Manganese in the shell of the bivalve Mytilus edulis: Seawater Mn or physiological control?

NASA Astrophysics Data System (ADS)

Freitas, Pedro S.; Clarke, Leon J.; Kennedy, Hilary; Richardson, Christopher A.

2016-12-01

Manganese in the shell calcite of marine bivalves has been suggested to reflect ambient seawater Mn concentrations, thus providing a high-resolution archive of past seawater Mn concentrations. However, a quantitative relationship between seawater Mn and shell Mn/Ca ratios, as well as clear understanding of which process(es) control(s) shell Mn/Ca, are still lacking. Blue mussels, Mytilus edulis, were grown in a one-year duration field experiment in the Menai Strait, U.K., to study the relationship between seawater particulate and dissolved Mn2+ concentrations and shell calcite Mn/Ca ratios. Shell Mn/Ca showed a well-defined intra-annual double-peak, with maximum values during early spring and early summer and low values during autumn and winter. Seawater particulate Mn peaked during winter and autumn, with a series of smaller peaks during spring and summer, whereas dissolved Mn2+ exhibited a marked single maximum during late-spring to early-summer, being low during the remainder of the year. Consequently, neither seawater particulate Mn nor dissolved Mn2+ concentrations explain the intra-annual variation of shell Mn/Ca ratios. A physiological control on shell Mn/Ca ratios is evident from the strong similarity and timing of the double-peaked intra-annual variations of Mn/Ca and shell growth rate (SGR), the latter corresponding to periods of increased metabolic activity (as indicated by respiration rate). It is thus likely that in M. edulis SGR influences shell Mn/Ca by altering the concentration or activity of Mn2+ within the extra-pallial fluid (EPF), by changing the flux of Mn into or the proportion of protein bound Mn within the EPF. By linking shell Mn/Ca ratios to the endogenous and environmental factors that determine growth and metabolic activity, this study helps to explain the lack of a consistent relationship between shell Mn/Ca in marine bivalve shell calcite and seawater particulate and dissolved Mn2+ concentrations. The use of Mn content from M. edulis shell calcite as a proxy for the dissolved and/or particulate Mn concentrations, and thus the biogeochemical processes that control them, remains elusive.

High performance 1.2 Ah Si-alloy/Graphite|LiNi0.5Mn0.3Co0.2O2 prototype Li-ion battery

NASA Astrophysics Data System (ADS)

Marinaro, Mario; Yoon, Dong-hwan; Gabrielli, Giulio; Stegmaier, Petra; Figgemeier, Egbert; Spurk, Paul C.; Nelis, Daniël; Schmidt, Gregory; Chauveau, Jerome; Axmann, Peter; Wohlfahrt-Mehrens, Margret

2017-07-01

The study reports on realization and electrochemical testing of prototype Si-alloy/Graphite|LiNi0.5Mn0.3Co0.2O2 batteries. Water soluble polyacrylic acid (PAA), used as the only binder at the anode side, demonstrates excellent dispersant and binding properties. Sedimentation tests and rheological measurements show remarkable stability and mostly a thinning behavior of the non-Newtonian type of slurry. The cathode is processed in N-Methylpyrrolidone based slurry using polyvinylidene fluoride (PVDF) as the binding agent. The electronic conductivities of the manufactured Si-alloy/Graphite and LiNi0.5Mn0.3Co0.2O2 electrodes are evaluated. Furthermore, the cathode and anode electrochemical behavior is initially studied in half-cells, and subsequently in full Li-ion stacked prototype soft pouch-cells (1.22 Ah). It is demonstrated that the manufactured prototype cells can sustain about 290 charge/discharge galvanostatic cycles before the retained capacity drops below 80%. Cell aging is monitored using Electrochemical Impedance Spectroscopy (EIS), whereas post-mortem SEM analysis of electrodes cross-section is used to shed light on the causes of performance degradation of the cells.

Mycobacterium tuberculosis whole cell lysate enhances proliferation of CD8 positive lymphocytes and nitric oxide secretion in the lungs of live porcine respiratory and reproductive syndrome virus vaccinated pigs.

PubMed

Manickam, Cordelia; Dwivedi, Varun; Miller, Jayla; Papenfuss, Tracey; Renukaradhya, Gourapura J

2013-02-01

Porcine respiratory and reproductive syndrome (PRRS) is an economically important disease of pigs worldwide. Currently used PRRSV vaccines provide incomplete protection. Recently, we identified Mycobacterium tuberculosis whole cell lysate (Mtb WCL) as a potent mucosal adjuvant to modified live PRRSV vaccine (PRRS-MLV). In this study, pigs were unvaccinated or vaccinated with PRRS-MLV plus Mtb WCL, intranasally, and challenged with either homologous (strain VR2332) or virulent heterologous (strain MN184) PRRSV; subsequently, euthanized at three time points post-challenge to evaluate lung immune responses. Microscopic examination of lung sections revealed reduced disruption of the lung architecture and less of interstitial pneumonia in vaccinated, compared to unvaccinated MN184 challenged pigs. The restimulated lung and peripheral blood mononuclear cells revealed increased proliferation of CD8(+) lymphocytes, and in the lung homogenate increased secretion of nitric oxide was detected in vaccinated MN184 challenged pigs. In summary, the adjuvant effects of Mtb WCL to PRRS-MLV resulted in favorable anti-PRRSV immune microenvironment in the lungs to help better viral clearance.

Mn(II,III) oxidation and MnO 2 mineralization by an expressed bacterial multicopper oxidase

DOE PAGES

Butterfield, Cristina N.; Soldatova, Alexandra V.; Lee, Sung -Woo; ...

2013-07-01

Reactive Mn(IV) oxide minerals are ubiquitous in the environment and control the bioavailability and distribution of many toxic and essential elements and organic compounds. Their formation is thought to be dependent on microbial enzymes, because spontaneous Mn(II) to Mn(IV) oxidation is slow. Several species of marine Bacillus spores oxidize Mn(II) on their exosporium, the outermost layer of the spore, encrusting them with Mn(IV) oxides. Molecular studies have identified the mnx (Mn oxidation) genes, including mnxG, encoding a putative multicopper oxidase (MCO), as responsible for this two-electron oxidation, a surprising finding because MCOs only catalyze single-electron transfer reactions. Characterization of themore » enzymatic mechanism has been hindered by the lack of purified protein. By purifying active protein from the mnxDEFG expression construct, we found that the resulting enzyme is a blue (absorption maximum 590 nm) complex containing MnxE, MnxF, and MnxG proteins. Further, by analyzing the Mn(II)- and (III)-oxidizing activity in the presence of a Mn(III) chelator, pyrophosphate, we found that the complex facilitates both electron transfers from Mn(II) to Mn(III) and from Mn(III) to Mn(IV). X-ray absorption spectroscopy of the Mn mineral product confirmed its similarity to Mn(IV) oxides generated by whole spores. Our results demonstrate that Mn oxidation from soluble Mn(II) to Mn(IV) oxides is a two-step reaction catalyzed by an MCO-containing complex. Lastly, with the purification of active Mn oxidase, we will be able to uncover its mechanism, broadening our understanding of Mn mineral formation and the bioinorganic capabilities of MCOs.« less

Mn(II,III) oxidation and MnO2 mineralization by an expressed bacterial multicopper oxidase

NASA Astrophysics Data System (ADS)

Butterfield, Cristina N.; Soldatova, Alexandra V.; Lee, Sung-Woo; Spiro, Thomas G.; Tebo, Bradley M.

2013-07-01

Reactive Mn(IV) oxide minerals are ubiquitous in the environment and control the bioavailability and distribution of many toxic and essential elements and organic compounds. Their formation is thought to be dependent on microbial enzymes, because spontaneous Mn(II) to Mn(IV) oxidation is slow. Several species of marine Bacillus spores oxidize Mn(II) on their exosporium, the outermost layer of the spore, encrusting them with Mn(IV) oxides. Molecular studies have identified the mnx (Mn oxidation) genes, including mnxG, encoding a putative multicopper oxidase (MCO), as responsible for this two-electron oxidation, a surprising finding because MCOs only catalyze single-electron transfer reactions. Characterization of the enzymatic mechanism has been hindered by the lack of purified protein. By purifying active protein from the mnxDEFG expression construct, we found that the resulting enzyme is a blue (absorption maximum 590 nm) complex containing MnxE, MnxF, and MnxG proteins. Further, by analyzing the Mn(II)- and (III)-oxidizing activity in the presence of a Mn(III) chelator, pyrophosphate, we found that the complex facilitates both electron transfers from Mn(II) to Mn(III) and from Mn(III) to Mn(IV). X-ray absorption spectroscopy of the Mn mineral product confirmed its similarity to Mn(IV) oxides generated by whole spores. Our results demonstrate that Mn oxidation from soluble Mn(II) to Mn(IV) oxides is a two-step reaction catalyzed by an MCO-containing complex. With the purification of active Mn oxidase, we will be able to uncover its mechanism, broadening our understanding of Mn mineral formation and the bioinorganic capabilities of MCOs.

Long-term manganese-toxicity-induced alterations of physiology and leaf protein profiles in two Citrus species differing in manganese-tolerance.

PubMed

You, Xiang; Yang, Lin-Tong; Qi, Yi-Ping; Guo, Peng; Lai, Ning-Wei; Ye, Xin; Li, Qiang; Chen, Li-Song

2017-11-01

Manganese (Mn)-intolerant 'Sour pummelo' (Citrus grandis) and Mn-tolerant 'Xuegan' (Citrus sinensis) seedlings were irrigated for 17 weeks with 2 (control) or 600μM (Mn-toxicity or -excess) MnSO 4 . C. sinensis had higher Mn-tolerance than C. grandis, as indicated by the higher photosynthesis rates in Mn-excess C. sinensis leaves. Under Mn-toxicity, Mn levels were similar between C. sinensis and C. grandis roots, but lower in C. sinensis leaves than in C. grandis leaves. This might be responsible for C. sinensis Mn-tolerance. Using two-dimensional electrophoresis, we identified more differentially abundant proteins (DAPs) in Mn-excess C. grandis than in Mn-excess C. sinensis leaves, which agrees with the higher Mn levels in Mn-excess C. grandis leaves. DAPs were mainly related to carbohydrate and energy metabolism, stress response, and protein and amino acid metabolism. DAPs involved in the cytoskeleton and signal transduction were found only in Mn-excess C. grandis leaves. We isolated more photosynthesis-related proteins with decreased abundances in Mn-excess C. grandis leaves than in Mn-excess C. sinensis leaves, which might account for the larger decrease in photosynthesis rates in C. grandis leaves. The abundances of proteins involved in reactive oxygen species (ROS) scavenging and photorespiration were increased in Mn-excess C. grandis leaves, while only proteins involved in ROS detoxification were increased in Mn-excess C. sinensis leaves. This agrees with the increased requirement for dissipating the excess absorbed light energy, which was higher in Mn-excess C. grandis leaves than Mn-excess C. sinensis leaves because Mn-toxicity inhibited photosynthesis to a greater degree in C. grandis leaves. Copyright © 2017 Elsevier GmbH. All rights reserved.

Mn(II,III) oxidation and MnO2 mineralization by an expressed bacterial multicopper oxidase

PubMed Central

Butterfield, Cristina N.; Soldatova, Alexandra V.; Lee, Sung-Woo; Spiro, Thomas G.; Tebo, Bradley M.

2013-01-01

Reactive Mn(IV) oxide minerals are ubiquitous in the environment and control the bioavailability and distribution of many toxic and essential elements and organic compounds. Their formation is thought to be dependent on microbial enzymes, because spontaneous Mn(II) to Mn(IV) oxidation is slow. Several species of marine Bacillus spores oxidize Mn(II) on their exosporium, the outermost layer of the spore, encrusting them with Mn(IV) oxides. Molecular studies have identified the mnx (Mn oxidation) genes, including mnxG, encoding a putative multicopper oxidase (MCO), as responsible for this two-electron oxidation, a surprising finding because MCOs only catalyze single-electron transfer reactions. Characterization of the enzymatic mechanism has been hindered by the lack of purified protein. By purifying active protein from the mnxDEFG expression construct, we found that the resulting enzyme is a blue (absorption maximum 590 nm) complex containing MnxE, MnxF, and MnxG proteins. Further, by analyzing the Mn(II)- and (III)-oxidizing activity in the presence of a Mn(III) chelator, pyrophosphate, we found that the complex facilitates both electron transfers from Mn(II) to Mn(III) and from Mn(III) to Mn(IV). X-ray absorption spectroscopy of the Mn mineral product confirmed its similarity to Mn(IV) oxides generated by whole spores. Our results demonstrate that Mn oxidation from soluble Mn(II) to Mn(IV) oxides is a two-step reaction catalyzed by an MCO-containing complex. With the purification of active Mn oxidase, we will be able to uncover its mechanism, broadening our understanding of Mn mineral formation and the bioinorganic capabilities of MCOs. PMID:23818588

Hair Manganese as an Exposure Biomarker among Welders.

PubMed

Reiss, Boris; Simpson, Christopher D; Baker, Marissa G; Stover, Bert; Sheppard, Lianne; Seixas, Noah S

2016-03-01

Quantifying exposure and dose to manganese (Mn) containing airborne particles in welding fume presents many challenges. Common biological markers such as Mn in blood or Mn in urine have not proven to be practical biomarkers even in studies where positive associations were observed. However, hair Mn (MnH) as a biomarker has the advantage over blood and urine that it is less influenced by short-term variability of Mn exposure levels because of its slow growth rate. The objective of this study was to determine whether hair can be used as a biomarker for welders exposed to manganese. Hair samples (1cm) were collected from 47 welding school students and individual air Mn (MnA) exposures were measured for each subject. MnA levels for all days were estimated with a linear mixed model using welding type as a predictor. A 30-day time-weighted average MnA (MnA30d) exposure level was calculated for each hair sample. The association between MnH and MnA30d levels was then assessed. A linear relationship was observed between log-transformed MnA30d and log-transformed MnH. Doubling MnA30d exposure levels yields a 20% (95% confidence interval: 11-29%) increase in MnH. The association was similar for hair washed following two different wash procedures designed to remove external contamination. Hair shows promise as a biomarker for inhaled Mn exposure given the presence of a significant linear association between MnH and MnA30d levels. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Hair Manganese as an Exposure Biomarker among Welders

PubMed Central

Reiss, Boris; Simpson, Christopher D.; Baker, Marissa G.; Stover, Bert; Sheppard, Lianne; Seixas, Noah S.

2016-01-01

Quantifying exposure and dose to manganese (Mn) containing airborne particles in welding fume presents many challenges. Common biological markers such as Mn in blood or Mn in urine have not proven to be practical biomarkers even in studies where positive associations were observed. However, hair Mn (MnH) as a biomarker has the advantage over blood and urine that it is less influenced by short-term variability of Mn exposure levels because of its slow growth rate. The objective of this study was to determine whether hair can be used as a biomarker for welders exposed to manganese. Hair samples (1cm) were collected from 47 welding school students and individual air Mn (MnA) exposures were measured for each subject. MnA levels for all days were estimated with a linear mixed model using welding type as a predictor. A 30-day time-weighted average MnA (MnA30d) exposure level was calculated for each hair sample. The association between MnH and MnA30d levels was then assessed. A linear relationship was observed between log-transformed MnA30d and log-transformed MnH. Doubling MnA30d exposure levels yields a 20% (95% confidence interval: 11–29%) increase in MnH. The association was similar for hair washed following two different wash procedures designed to remove external contamination. Hair shows promise as a biomarker for inhaled Mn exposure given the presence of a significant linear association between MnH and MnA30d levels. PMID:26409267

Operando identification of the point of [Mn- 2]O- 4 spinel formation during gamma-MnO 2 discharge within batteries

DOE PAGES

Gallaway, Joshua W.; Hertzberg, Benjamin J.; Zhong, Zhong; ...

2016-05-07

The rechargeability of γ-MnO 2 cathodes in alkaline batteries is limited by the formation of the [Mn 2]O 4 spinels ZnMn 2O 4 (hetaerolite) and Mn 3O 4 (hausmannite). However, the time and formation mechanisms of these spinels are not well understood. Here we directly observe γ-MnO 2 discharge at a range of reaction extents distributed across a thick porous electrode. Coupled with a battery model, this reveals that spinel formation occurs at a precise and predictable point in the reaction, regardless of reaction rate. Observation is accomplished by energy dispersive X-ray diffraction (EDXRD) using photons of high energy andmore » high flux, which penetrate the cell and provide diffraction data as a function of location and time. After insertion of 0.79 protons per γ-MnO 2 the α-MnOOH phase forms rapidly. α-MnOOH is the precursor to spinel, which closely follows. ZnMn 2O 4 and Mn 3O 4 form at the same discharge depth, by the same mechanism. The results show the final discharge product, Mn 3O 4 or Mn(OH) 2, is not an intrinsic property of γ-MnO 2. While several studies have identified Mn(OH) 2 as the final γ-MnO 2 discharge product, we observe direct conversion to Mn 3O 4 with no Mn(OH) 2.« less

Fungal oxidative dissolution of the Mn(II)-bearing mineral rhodochrosite and the role of metabolites in manganese oxide formation.

PubMed

Tang, Yuanzhi; Zeiner, Carolyn A; Santelli, Cara M; Hansel, Colleen M

2013-04-01

Microbially mediated oxidation of Mn(II) to Mn(III/IV) oxides influences the cycling of metals and remineralization of carbon. Despite the prevalence of Mn(II)-bearing minerals in nature, little is known regarding the ability of microbes to oxidize mineral-hosted Mn(II). Here, we explored oxidation of the Mn(II)-bearing mineral rhodochrosite (MnCO3 ) and characteristics of ensuing Mn oxides by six Mn(II)-oxidizing Ascomycete fungi. All fungal species substantially enhanced rhodochrosite dissolution and surface modification. Mineral-hosted Mn(II) was oxidized resulting in formation of Mn(III/IV) oxides that were all similar to δ-MnO2 but varied in morphology and distribution in relation to cellular structures and the MnCO3 surface. For four fungi, Mn(II) oxidation occurred along hyphae, likely mediated by cell wall-associated proteins. For two species, Mn(II) oxidation occurred via reaction with fungal-derived superoxide produced at hyphal tips. This pathway ultimately resulted in structurally unique Mn oxide clusters formed at substantial distances from any cellular structure. Taken together, findings for these two fungi strongly point to a role for fungal-derived organic molecules in Mn(III) complexation and Mn oxide templation. Overall, this study illustrates the importance of fungi in rhodochrosite dissolution, extends the relevance of biogenic superoxide-based Mn(II) oxidation and highlights the potential role of mycogenic exudates in directing mineral precipitation. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Manganese acquisition by Lactobacillus plantarum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Archibald, F.S.; Duong, M.N.

1984-04-01

Lactobacillus plantarum has an unusually high Mn(II) requirement for growth and accumulated over 30 mM intracellular Mn(II). The acquisition of Mn(II) by L. plantarum occurred via a specific active transport system powered by the transmembrane proton gradient. The Mn(II) uptake system has a K/sub m/ of 0.2 ..mu..M and a V/sub max/ of 24 nmol mg/sup -1/ of protein min/sup -1/. Above a medium Mn(II) concentration of 200 ..mu..M, the intracellular Mn(II) level was independent of the medium Mn(II) and unresponsive to oxygen stresses but was reduced by phosphate limitation. At a pH of 5.5, citrate, isocitrate, and cis-aconitate effectivelymore » promoted MN(II) uptake, although measurable levels of 1,5-(/sup 14/C)citrate were not accumulated. When cells were presented with equimolar Mn(II) and Cd(II), Cd(II) was preferentially taken up by the Mn(II) transport system. Both Mn(II) and Cd(II) uptake were greatly increased by Mn(II) starvation. Mn(II) uptake by Mn(II)-starved cells was subject to a negative feedback regulatory mechanism functioning less than 1 min after exposure of the cells to Mn(II) and independent of protein synthesis. When presented with a relatively large amount of exogenous Mn(II), Mn(II)-starved cells exhibited a measurable efflux of their internal Mn(II), but the rate was only a small fraction of the maximal Mn(II) uptake rate.« less

Magnetic properties of transition metal substituted La 0.85Ag 0.15Mn 1-yM yO 3 compounds (M=Co, Cr and Al)

NASA Astrophysics Data System (ADS)

Srivastava, S. K.; Ravi, S.

2009-12-01

In this paper we report a systematic study of Mn-site substitution by M=Co, Cr and Al in La 0.85Ag 0.15MnO 3 series to understand the magnetic interactions between Mn and other transition metals. The long-range ferromagnetic (FM) ordering of the parent compound was significantly affected by Mn-site substitution. The measured magnetic properties of Co-doped samples have been explained on the basis of FM interactions in Mn 3+-O-Mn 4+, Co 2+-O-Mn 4+, Co 3+-O-Mn 4+ networks and simultaneous antiferromagnetic (AFM) interactions in Mn 4+-O-Mn 4+, Co 2+-O-Mn 3+ networks. The magnetic properties of Cr-doped compounds could be understood on the basis of double exchange FM interactions in Mn 3+-O 2--Mn 4+ networks and competing AFM in Cr 3+-O-Mn 4+, Mn 4+-O-Mn 4+, Cr 3+-O-Mn 3+ networks. However, it is found that the doping of Al ions play a role of magnetic dilution, without contributing any other competing magnetic interaction. The field variations of magnetization of all the above three series could be analysed by fitting to Brillouin function model and the effective spin contribution for FM has been determined. The measured saturation magnetization has been explained quantitatively.

Mn2+ concentration manipulated red emission in BaMg2Si2O7:Eu2+,Mn2+

NASA Astrophysics Data System (ADS)

Ye, Song; Zhang, Jiahua; Zhang, Xia; Lu, Shaozhe; Ren, Xinguang; Wang, Xiaojun

2007-02-01

The luminescent properties of concentration dependence are reported in BaMg2Si2O7:Eu2+,Mn2+ red phosphor. It is observed that the broad red emission of Mn2+ consists of two bands, located at 620 and 675 nm, respectively, which are attributed to two different Mn2+ centers [Mn2+(I) and Mn2+(II)] substituting for two nonidentical Mg2+ sites [Mg2+(I) and Mg2+(II)] in the host. It is also found that the relative emission intensity of the Mn2+(II) to the Mn2+(I) increases with increasing Mn2+ concentration, leading to a red-shift of the overall emission. A detail analysis on the energy transfer from Eu2+ to the two Mn2+ centers is presented, which indicates that the number ratio of Mn2+(II) to Mn2+(I) increases with increasing Mn2+ concentration. This result is interpreted by the preferential formation of Mn2+(I) substituting for Mg2+(I) site. Based on energy transfer, the emission intensity ratios of Mn2+(I) to Eu2+ and Mn2+(II) to Eu2+, which is Mn2+ concentration dependent, are calculated using related fluorescence lifetimes. The calculated results are in good agreement with that obtained experimentally in the emission spectra.

Reduced graphene oxide supported MnS nanotubes hybrid as a novel non-precious metal electrocatalyst for oxygen reduction reaction with high performance

NASA Astrophysics Data System (ADS)

Tang, Yongfu; Chen, Teng; Guo, Wenfeng; Chen, Shunji; Li, Yanshuai; Song, Jianzheng; Chang, Limin; Mu, Shichun; Zhao, Yufeng; Gao, Faming

2017-09-01

Electronic structure of Mn cations, electric conductivity of active materials and three dimensional structure for mass transport play vital roles in the electrocatalytic activity of Mn-based electrocatalysts for oxygen reduction reaction (ORR). To construct efficient and robust Mn-based electrocatalysts, MnS nanotubes anchored on reduced graphene oxide (MnS-NT@rGO) hybrid was synthesized and used as a novel non-precious metal electrocatalyst for ORR. The formation of nano-tubular structure, which offers more active sites and suitable channels for mass transport to enhance the electrocatalytic activity towards ORR, are carefully illustrated based on the core-dissolution/shell-recrystallization type Ostwald ripening effect. Tuned electronic structure of Mn cations, enhanced electric conductivity and suitable nano-tubular structure endow MnS-NT@rGO electrocatalyst comparative catalytic activity to commercial 20 wt % Pt/C in alkaline electrolyte. The MnS-NT@rGO electrocatalyst exhibits higher catalytic activity than rGO supported MnS nanoparticles (MnS-NP@rGO) and MnS nanotubes without rGO substrate (MnS-NT), as well as rGO supported Mn(OH)2 (Mn(OH)2@rGO) and rGO supported MnO (MnO@rGO). Moreover, the MnS-NT@rGO electrocatalyst shows superior durability and methanol tolerance to commercial Pt/C.

Multicopper Oxidase Involvement in Both Mn(II) and Mn(III) Oxidation during Bacterial Formation of MnO2

PubMed Central

Soldatova, Alexandra V.; Butterfield, Cristina; Oyerinde, Oyeyemi F.; Tebo, Bradley M.; Spiro, Thomas G.

2013-01-01

Global cycling of environmental manganese requires catalysis by bacteria and fungi for MnO2 formation, since abiotic Mn(II) oxidation is slow under ambient conditions. Genetic evidence from several bacteria implicates multicopper oxidases (MCOs) as being required for MnO2 formation. However, MCOs catalyze one-electron oxidations, whereas conversion of Mn(II) to MnO2 is a two-electron process. Trapping experiments with pyrophosphate (PP), a Mn(III) chelator, have demonstrated that Mn(III) is an intermediate in Mn(II) oxidation when mediated by exosporium from the Mn-oxidizing bacterium Bacillus SG-1. The reaction of Mn(II) depends on O2 and is inhibited by azide, consistent with MCO catalysis. We show that the subsequent conversion of Mn(III) to MnO2 also depends on O2 and is inhibited by azide. Thus, both oxidation steps appear to be MCO-mediated, likely by the same enzyme, indicated by genetic evidence to be the MnxG gene product. We propose a model of how the manganese oxidase active site may be organized to couple successive electron transfers to the formation of polynuclear Mn(IV) complexes as precursors to MnO2 formation. PMID:22892957

Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge compensation.

PubMed

Lassalle-Kaiser, Benedikt; Hureau, Christelle; Pantazis, Dimitrios A; Pushkar, Yulia; Guillot, Régis; Yachandra, Vittal K; Yano, Junko; Neese, Frank; Anxolabéhère-Mallart, Elodie

2010-07-01

Activation of a water molecule by the electrochemical oxidation of a Mn-aquo complex accompanied by the loss of protons is reported. The sequential (2 × 1 electron/1 proton) and direct (2 electron/2 proton) proton-coupled electrochemical oxidation of a non-porphyrinic six-coordinated Mn(II)OH 2 complex into a mononuclear Mn(O) complex is described. The intermediate Mn(III)OH 2 and Mn(III)OH complexes are electrochemically prepared and analysed. Complete deprotonation of the coordinated water molecule in the Mn(O) complex is confirmed by electrochemical data while the analysis of EXAFS data reveals a gradual shortening of an Mn-O bond upon oxidation from Mn(II)OH 2 to Mn(III)OH and Mn(O). Reactivity experiments, DFT calculations and XANES pre-edge features provide strong evidence that the bonding in Mn(O) is best characterized by a Mn(III)-oxyl description. Such oxyl species could play a crucial role in natural and artificial water splitting reactions. We provide here a synthetic example for such species, obtained by electrochemical activation of a water ligand.

Structure and properties of Mn4Cl9: an antiferromagnetic binary hyperhalogen.

PubMed

Li, Yawei; Zhang, Shunhong; Wang, Qian; Jena, Puru

2013-02-07

Calculations based on density functional theory show that the structure of Mn(4)Cl(9) anion is that of a Mn atom at the core surrounded by three MnCl(3) moieties. Since Mn is predominantly divalent and MnCl(3) is known to be a superhalogen with a vertical detachment energy (VDE) of 5.27 eV, Mn(4)Cl(9) can be viewed as a hyperhalogen with the formula unit Mn(MnCl(3))(3). Indeed, the calculated VDE of Mn(4)Cl(9) anion, namely 6.76 eV, is larger than that of MnCl(3) anion. More importantly, unlike previously discovered hyperhalogens, Mn(4)Cl(9) is the first such hyperhalogen species composed of only two constituent atoms. We further show that Mn(4)Cl(9) can be used as a ligand to design molecules with even higher VDEs. For example, Li[Mn(MnCl(3))(3)](2) anion has a VDE of 7.26 eV. These negatively charged clusters are antiferromagnetic with most of the magnetic moments localized at the Mn sites. Our studies show new pathways for creating binary hyperhalogens.

Structure and properties of Mn4Cl9: An antiferromagnetic binary hyperhalogen

NASA Astrophysics Data System (ADS)

Li, Yawei; Zhang, Shunhong; Wang, Qian; Jena, Puru

2013-02-01

Calculations based on density functional theory show that the structure of Mn4Cl9 anion is that of a Mn atom at the core surrounded by three MnCl3 moieties. Since Mn is predominantly divalent and MnCl3 is known to be a superhalogen with a vertical detachment energy (VDE) of 5.27 eV, Mn4Cl9 can be viewed as a hyperhalogen with the formula unit Mn(MnCl3)3. Indeed, the calculated VDE of Mn4Cl9 anion, namely 6.76 eV, is larger than that of MnCl3 anion. More importantly, unlike previously discovered hyperhalogens, Mn4Cl9 is the first such hyperhalogen species composed of only two constituent atoms. We further show that Mn4Cl9 can be used as a ligand to design molecules with even higher VDEs. For example, Li[Mn(MnCl3)3]2 anion has a VDE of 7.26 eV. These negatively charged clusters are antiferromagnetic with most of the magnetic moments localized at the Mn sites. Our studies show new pathways for creating binary hyperhalogens.

Direct effects of manganese compounds on dopamine and its metabolite Dopac: an in vitro study

PubMed Central

Sistrunk, Shannon C.; Ross, Matthew K.; Filipov, Nikolay M.

2007-01-01

Following combustion of fuel containing the additive methylcyclopentadienyl-manganese-tricarbonyl (MMT), manganese phosphate (MnPO4) and manganese sulfate (MnSO4) are emitted in the atmosphere. Manganese chloride (MnCl2), another Mn2+ species, is widely used experimentally. Using rat striatal slices, we found that MnPO4 decreased tissue and media dopamine (DA) and media Dopac (a DA metabolite) levels substantially more than either MnCl2 or MnSO4; antioxidants were partially protective. Also, both MnCl2 and MnPO4 (more potently) oxidized DA and Dopac even in the absence of tissue in the media, suggesting a direct interaction between Mn and DA/Dopac. Because aminochrome is a major oxidation product of DA, we next determined whether MnPO4 will be more potent in forming aminochrome than MnCl2 or MnSO4 which, indeed, was the case. Thus, a potential additional mechanism for the neurotoxic effects of environmentally-relevant forms of Mn, MnPO4 in particular, is the generation of reactive DA intermediates. PMID:18449324

The Self-Referring Text: Strategies and Intentions.

ERIC Educational Resources Information Center

Washington, Gene

This paper discusses self-reference in the text, in order to examine its rhetorical intentions, and the writing strategies it offers an author. Following a brief introduction, the first section deals with definitions, and classifies self-reference "markers." The second section discusses intentions and self-reference, while the third…

39 CFR 20.1 - International Mail Manual; incorporation by reference.

Code of Federal Regulations, 2010 CFR

2010-07-01

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40 CFR 1042.910 - Reference materials.

Code of Federal Regulations, 2010 CFR

2010-07-01

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40 CFR 1042.910 - Reference materials.

Code of Federal Regulations, 2014 CFR

2014-07-01

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40 CFR 1043.100 - Reference materials.

Code of Federal Regulations, 2014 CFR

2014-07-01

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Vertical Geochemical Variations and Speciation Studies of As, Fe, Mn, Zn, and Cu in the Sediments of the Central Gangetic Basin: Sequential Extraction and Statistical Approach

PubMed Central

Ramanathan, AL.

2018-01-01

A geochemical and speciation study of As, Fe, Mn, Zn, and Cu was performed using sequential extraction and statistical approaches in the core sediments taken at two locations—Rigni Chhapra and Chaube Chhapra—of the central Gangetic basin (India). A gradual increase in the grain size (varying from clay to coarse sands) was observed in both the core profiles up to 30.5 m depth. The concentrations of analyzed elements ranged as follows: 6.9–14.2 mg/kg for As, 13,849–31,088 mg/kg for Fe, 267–711 mg/kg for Mn, 45–164 mg/kg for Cu for Rigni Chhapra while for Chaube Chhapra the range was 7.5–13.2 mg/kg for As, 10,936–37,052 mg/kg for Fe, 267–1052 mg/kg for Mn, 60–198 mg/kg for Zn and 60–108 mg/kg for Cu. Significant amounts (53–95%) of all the fractionated elemental concentrations were bound within the crystal structure of the minerals as a residual fraction. The reducible fraction was the second most dominant fraction for As (7% and 8%), Fe (3%), Mn (20% and 26%), and Cu (7% and 6%) respectively for both the cores. It may be released when aquifers subjected to changing redox conditions. The acid soluble fraction was of most interest because it could quickly mobilize into the water system which formed the third most dominating among all three fractions. Four color code of sediments showed an association with total As concentration and did not show a relation with any fraction of all elements analyzed. The core sediment was observed enriched with As and other elements (Cu, Fe, Mn, and Zn). However, it fell under uncontaminated to moderately contaminate which might exhibit a low risk in prevailing natural conditions. X-ray diffraction analyses indicated the availability of siderite and magnetite minerals in the core sediments in a section of dark grey with micaceous medium sand with organic matter (black). PMID:29360767

Mn(II) Oxidation by the Multicopper Oxidase Complex Mnx: A Binuclear Activation Mechanism.

PubMed

Soldatova, Alexandra V; Tao, Lizhi; Romano, Christine A; Stich, Troy A; Casey, William H; Britt, R David; Tebo, Bradley M; Spiro, Thomas G

2017-08-23

The bacterial protein complex Mnx contains a multicopper oxidase (MCO) MnxG that, unusually, catalyzes the two-electron oxidation of Mn(II) to MnO 2 biomineral, via a Mn(III) intermediate. Although Mn(III)/Mn(II) and Mn(IV)/Mn(III) reduction potentials are expected to be high, we find a low reduction potential, 0.38 V (vs Normal Hydrogen Electrode, pH 7.8), for the MnxG type 1 Cu 2+ , the electron acceptor. Indeed the type 1 Cu 2+ is not reduced by Mn(II) in the absence of molecular oxygen, indicating that substrate oxidation requires an activation step. We have investigated the enzyme mechanism via electronic absorption spectroscopy, using chemometric analysis to separate enzyme-catalyzed MnO 2 formation from MnO 2 nanoparticle aging. The nanoparticle aging time course is characteristic of nucleation and particle growth; rates for these processes followed expected dependencies on Mn(II) concentration and temperature, but exhibited different pH optima. The enzymatic time course is sigmoidal, signaling an activation step, prior to turnover. The Mn(II) concentration and pH dependence of a preceding lag phase indicates weak Mn(II) binding. The activation step is enabled by a pK a > 8.6 deprotonation, which is assigned to Mn(II)-bound H 2 O; it induces a conformation change (consistent with a high activation energy, 106 kJ/mol) that increases Mn(II) affinity. Mnx activation is proposed to decrease the Mn(III/II) reduction potential below that of type 1 Cu(II/I) by formation of a hydroxide-bridged binuclear complex, Mn(II)(μ-OH)Mn(II), at the substrate site. Turnover is found to depend cooperatively on two Mn(II) and is enabled by a pK a 7.6 double deprotonation. It is proposed that turnover produces a Mn(III)(μ-OH) 2 Mn(III) intermediate that proceeds to the enzyme product, likely Mn(IV)(μ-O) 2 Mn(IV) or an oligomer, which subsequently nucleates MnO 2 nanoparticles. We conclude that Mnx exploits manganese polynuclear chemistry in order to facilitate an otherwise difficult oxidation reaction, as well as biomineralization. The mechanism of the Mn(III/IV) conversion step is elucidated in an accompanying paper .

DOE Office of Scientific and Technical Information (OSTI.GOV)

WINCHELL, D.F.

This document lists experimental references added to Nuclear Science References (NSR) during the period January 1, 2005 to December 31, 2005. The first section lists keynumbers and keywords sorted by mass and nuclide. The second section lists all references, ordered by keynumber.

DOE Office of Scientific and Technical Information (OSTI.GOV)

WINCHELL, D.F.

This document lists experimental references added to Nuclear Science References (NSR) during the period April 1, 2005 to June 30, 2005. The first section lists keynumbers and keywords sorted by mass and nuclide. The second section lists all references, ordered by keynumber.

Oxidative Formation and Removal of Complexed Mn(III) by Pseudomonas Species

PubMed Central

Wright, Mitchell H.; Geszvain, Kati; Oldham, Véronique E.; Luther, George W.; Tebo, Bradley M.

2018-01-01

The observation of significant concentrations of soluble Mn(III) complexes in oxic, suboxic, and some anoxic waters has triggered a re-evaluation of the previous Mn paradigm which focused on the cycling between soluble Mn(II) and insoluble Mn(III,IV) species as operationally defined by filtration. Though Mn(II) oxidation in aquatic environments is primarily bacterially-mediated, little is known about the effect of Mn(III)-binding ligands on Mn(II) oxidation nor on the formation and removal of Mn(III). Pseudomonas putida GB-1 is one of the most extensively investigated of all Mn(II) oxidizing bacteria, encoding genes for three Mn oxidases (McoA, MnxG, and MopA). P. putida GB-1 and associated Mn oxidase mutants were tested alongside environmental isolates Pseudomonas hunanensis GSL-007 and Pseudomonas sp. GSL-010 for their ability to both directly oxidize weakly and strongly bound Mn(III), and to form these complexes through the oxidation of Mn(II). Using Mn(III)-citrate (weak complex) and Mn(III)-DFOB (strong complex), it was observed that P. putida GB-1, P. hunanensis GSL-007 and Pseudomonas sp. GSL-010 and mutants expressing only MnxG and McoA were able to directly oxidize both species at varying levels; however, no oxidation was detected in cultures of a P. putida mutant expressing only MopA. During cultivation in the presence of Mn(II) and citrate or DFOB, P. putida GB-1, P. hunanensis GSL-007 and Pseudomonas sp. GSL-010 formed Mn(III) complexes transiently as an intermediate before forming Mn(III/IV) oxides with the overall rates and extents of Mn(III,IV) oxide formation being greater for Mn(III)-citrate than for Mn(III)-DFOB. These data highlight the role of bacteria in the oxidative portion of the Mn cycle and suggest that the oxidation of strong Mn(III) complexes can occur through enzymatic mechanisms involving multicopper oxidases. The results support the observations from field studies and further emphasize the complexity of the geochemical cycling of manganese. PMID:29706936

Oxidative Formation and Removal of Complexed Mn(III) by Pseudomonas Species.

PubMed

Wright, Mitchell H; Geszvain, Kati; Oldham, Véronique E; Luther, George W; Tebo, Bradley M

2018-01-01

The observation of significant concentrations of soluble Mn(III) complexes in oxic, suboxic, and some anoxic waters has triggered a re-evaluation of the previous Mn paradigm which focused on the cycling between soluble Mn(II) and insoluble Mn(III,IV) species as operationally defined by filtration. Though Mn(II) oxidation in aquatic environments is primarily bacterially-mediated, little is known about the effect of Mn(III)-binding ligands on Mn(II) oxidation nor on the formation and removal of Mn(III). Pseudomonas putida GB-1 is one of the most extensively investigated of all Mn(II) oxidizing bacteria, encoding genes for three Mn oxidases (McoA, MnxG, and MopA). P. putida GB-1 and associated Mn oxidase mutants were tested alongside environmental isolates Pseudomonas hunanensis GSL-007 and Pseudomonas sp. GSL-010 for their ability to both directly oxidize weakly and strongly bound Mn(III), and to form these complexes through the oxidation of Mn(II). Using Mn(III)-citrate (weak complex) and Mn(III)-DFOB (strong complex), it was observed that P. putida GB-1, P. hunanensis GSL-007 and Pseudomonas sp. GSL-010 and mutants expressing only MnxG and McoA were able to directly oxidize both species at varying levels; however, no oxidation was detected in cultures of a P. putida mutant expressing only MopA. During cultivation in the presence of Mn(II) and citrate or DFOB, P. putida GB-1, P. hunanensis GSL-007 and Pseudomonas sp. GSL-010 formed Mn(III) complexes transiently as an intermediate before forming Mn(III/IV) oxides with the overall rates and extents of Mn(III,IV) oxide formation being greater for Mn(III)-citrate than for Mn(III)-DFOB. These data highlight the role of bacteria in the oxidative portion of the Mn cycle and suggest that the oxidation of strong Mn(III) complexes can occur through enzymatic mechanisms involving multicopper oxidases. The results support the observations from field studies and further emphasize the complexity of the geochemical cycling of manganese.

Constraints on superoxide mediated formation of manganese oxides

PubMed Central

Learman, Deric R.; Voelker, Bettina M.; Madden, Andrew S.; Hansel, Colleen M.

2013-01-01

Manganese (Mn) oxides are among the most reactive sorbents and oxidants within the environment, where they play a central role in the cycling of nutrients, metals, and carbon. Recent discoveries have identified superoxide (O2−) both of biogenic and abiogenic origin as an effective oxidant of Mn(II) leading to the formation of Mn oxides. Here we examined the conditions under which abiotically produced superoxide led to oxidative precipitation of Mn and the solid-phases produced. Oxidized Mn, as both aqueous Mn(III) and Mn(III/IV) oxides, was only observed in the presence of active catalase, indicating that hydrogen peroxide (H2O2), a product of the reaction of O2− with Mn(II), inhibits the oxidation process presumably through the reduction of Mn(III). Citrate and pyrophosphate increased the yield of oxidized Mn but decreased the amount of Mn oxide produced via formation of Mn(III)-ligand complexes. While complexing ligands played a role in stabilizing Mn(III), they did not eliminate the inhibition of net Mn(III) formation by H2O2. The Mn oxides precipitated were highly disordered colloidal hexagonal birnessite, similar to those produced by biotically generated superoxide. Yet, in contrast to the large particulate Mn oxides formed by biogenic superoxide, abiotic Mn oxides did not ripen to larger, more crystalline phases. This suggests that the deposition of crystalline Mn oxides within the environment requires a biological, or at least organic, influence. This work provides the first direct evidence that, under conditions relevant to natural waters, oxidation of Mn(II) by superoxide can occur and lead to formation of Mn oxides. For organisms that oxidize Mn(II) by producing superoxide, these findings may also point to other microbially mediated processes, in particular enzymatic hydrogen peroxide degradation and/or production of organic ligand metabolites, that allow for Mn oxide formation. PMID:24027565

Stability of βMnOOH and manganese oxide deposition from springwater

USGS Publications Warehouse

Hem, J.D.; Roberson, C.E.; Fournier, Reba B.

1982-01-01

Beta MnOOH is precipitated preferentially (with respect to Mn3O4) at temperatures near O°C when Mn2+ is oxidized in aerated aqueous solutions. Upon aging in solutions open to the atmosphere a slurry of βMnOOH tends to disproportionate to form MnO2 and Mn2+. In such aged solutions, Mn2+ and H+ activities can be constant, and both the oxidation reaction Mn2++¼O2(aq) + 3/2H2O → βMnOOH (c) + 2H+ and the disproportionate reaction 2βMnOOH (c) + 2H+ → MnO2(c) + Mn2+ + 2H2O can have positive reaction affinities. It is not possible for both reactions to be in thermodynamic equilibrium in the same system unless oxygen is almost completely absent. A value for ΔGf0 of −129.8±0.6 kcal/mol was obtained for βMnOOH from experimental data by assuming that the reaction affinity for the oxidation reaction is equal to that for the disproportionation. A value for ΔGf0 for βMnOOH of −129.8±0.5 kcal/mol was determined by measuring the redox potentials for the postulated half-reaction MnO2 (c) + H+ + e− → βMnOOH (c) at 0°, 5°, and 15°C and extrapolating to 25°C. Both these values are consistent with laboratory observations that βMnOOH is less stable than γMnOOH or Mn3O4 at 25°C. Analytical data for manganese-depositing springwater samples are consistent with a nonequilibrium model involving disproportionation of either βMnOOH or Mn3O4.

Novel Co- or Ni-Mn binary oxide catalysts with hydroxyl groups for NH3-SCR of NOx at low temperature

NASA Astrophysics Data System (ADS)

Gao, Fengyu; Tang, Xiaolong; Yi, Honghong; Zhao, Shunzheng; Wang, Jiangen; Shi, Yiran; Meng, Xiaomi

2018-06-01

Novel hydroxyl-containing Me-Mn binary oxides (Me = Co, Ni) were prepared for the selective catalytic reduction of NOx with NH3 by a combined complexation-esterification method. The binary oxides of Co-MnOx and Ni-MnOx with mixed crystal phases of Mn3O4 and Co3O4, Mn2O3 and NiMnO3 were obtained at 550 °C. SCR activity decreased in the order of Mn3O4-Co3O4-OH > Mn2O3-NiMnO3-OH > Mn2O3-OH > Mn3O4-OH, benefiting from the high concentration of chemisorbed oxygen and effective electron transformation of cations. Mn2O3-containing catalysts had better selectivity to N2 than those containing Mn3O4. Higher selectivity to N2O over Mn3O4-containing catalysts was attributed to the depth dehydrogenation of coordinated NH3 by the active oxygen species with lower Mnsbnd O band energy. The typical Eley-Rideal mechanism over Mn3O4-OH and Mn3O4-Co3O4-OH, and the additional formation pathway of NH4NO3 species over Mn2O3-OH and Mn2O3-NiMnO3-OH catalysts were proposed via the in-situ DRIFTS experiments. Although the Co and Ni elements had a good role in delaying the poisoning of SO2, these catalysts were eventually sulfated by SO2 over the postponement, which might due to the metal sulfate and ammonia hydrogensulfite species.

Dissociation kinetics of Mn2+ complexes of NOTA and DOTA.

PubMed

Drahoš, Bohuslav; Kubíček, Vojtěch; Bonnet, Célia S; Hermann, Petr; Lukeš, Ivan; Tóth, Éva

2011-03-07

The kinetics of transmetallation of [Mn(nota)](-) and [Mn(dota)](2-) was investigated in the presence of Zn(2+) (5-50-fold excess) at variable pH (3.5-5.6) by (1)H relaxometry. The dissociation is much faster for [Mn(nota)](-) than for [Mn(dota)](2-) under both experimental and physiologically relevant conditions (t(½) = 74 h and 1037 h for [Mn(nota)](-) and [Mn(dota)](2-), respectively, at pH 7.4, c(Zn(2+)) = 10(-5) M, 25 °C). The dissociation of the complexes proceeds mainly via spontaneous ([Mn(nota)](-)k(0) = (2.6 ± 0.5) × 10(-6) s(-1); [Mn(dota)](2-)k(0) = (1.8 ± 0.6) × 10(-7) s(-1)) and proton-assisted pathways ([Mn(nota)](-)k(1) = (7.8 ± 0.1) × 10(-1) M(-1) s(-1); [Mn(dota)](2-)k(1) = (4.0 ± 0.6) × 10(-2) M(-1) s(-1), k(2) = (1.6 ± 0.1) × 10(3) M(-2) s(-1)). The observed suppression of the reaction rates with increasing Zn(2+) concentration is explained by the formation of a dinuclear Mn(2+)-L-Zn(2+) complex which is about 20-times more stable for [Mn(dota)](2-) than for [Mn(nota)](-) (K(MnLZn) = 68 and 3.6, respectively), and which dissociates very slowly (k(3)∼10(-5) M(-1) s(-1)). These data provide the first experimental proof that not all Mn(2+) complexes are kinetically labile. The absence of coordinated water makes both [Mn(nota)](-) and [Mn(dota)](2-) complexes inefficient for MRI applications. Nevertheless, the higher kinetic inertness of [Mn(dota)](2-) indicates a promising direction in designing ligands for Mn(2+) complexation.

Ferromagnetic dinuclear mixed-valence Mn(II)/Mn(III) complexes: building blocks for the higher nuclearity complexes. structure, magnetic properties, and density functional theory calculations.

PubMed

Hänninen, Mikko M; Välivaara, Juha; Mota, Antonio J; Colacio, Enrique; Lloret, Francesc; Sillanpää, Reijo

2013-02-18

A series of six mixed-valence Mn(II)/Mn(III) dinuclear complexes were synthesized and characterized by X-ray diffraction. The reactivity of the complexes was surveyed, and structures of three additional trinuclear mixed-valence Mn(III)/Mn(II)/Mn(III) species were resolved. The magnetic properties of the complexes were studied in detail both experimentally and theoretically. All dinuclear complexes show ferromagnetic intramolecular interactions, which were justified on the basis of the electronic structures of the Mn(II) and Mn(III) ions. The large Mn(II)-O-Mn(III) bond angle and small distortion of the Mn(II) cation from the ideal square pyramidal geometry were shown to enhance the ferromagnetic interactions since these geometrical conditions seem to favor the orthogonal arrangement of the magnetic orbitals.

Surface Mn(II) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals

PubMed Central

Zhang, Zhen; Zhang, Zhongming; Chen, Hong; Liu, Jin; Liu, Chang; Ni, Hong; Zhao, Changsong; Ali, Muhammad; Liu, Fan; Li, Lin

2015-01-01

In this manuscript, we report that a bacterial multicopper oxidase (MCO266) catalyzes Mn(II) oxidation on the cell surface, resulting in the surface deposition of Mn(III) and Mn(IV) oxides and the gradual formation of bulky oxide aggregates. These aggregates serve as nucleation centers for the formation of Mn oxide micronodules and Mn-rich sediments. A soil-borne Escherichia coli with high Mn(II)-oxidizing activity formed Mn(III)/Mn(IV) oxide deposit layers and aggregates under laboratory culture conditions. We engineered MCO266 onto the cell surfaces of both an activity-negative recipient and wild-type strains. The results confirmed that MCO266 governs Mn(II) oxidation and initiates the formation of deposits and aggregates. By contrast, a cell-free substrate, heat-killed strains, and intracellularly expressed or purified MCO266 failed to catalyze Mn(II) oxidation. However, purified MCO266 exhibited Mn(II)-oxidizing activity when combined with cell outer membrane component (COMC) fractions in vitro. We demonstrated that Mn(II) oxidation and aggregate formation occurred through an oxygen-dependent biotic transformation process that requires a certain minimum Mn(II) concentration. We propose an approximate electron transfer pathway in which MCO266 transfers only one electron to convert Mn(II) to Mn(III) and then cooperates with other COMC electron transporters to transfer the other electron required to oxidize Mn(III) to Mn(IV). PMID:26039669

Surface Mn(II) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals.

PubMed

Zhang, Zhen; Zhang, Zhongming; Chen, Hong; Liu, Jin; Liu, Chang; Ni, Hong; Zhao, Changsong; Ali, Muhammad; Liu, Fan; Li, Lin

2015-06-03

In this manuscript, we report that a bacterial multicopper oxidase (MCO266) catalyzes Mn(II) oxidation on the cell surface, resulting in the surface deposition of Mn(III) and Mn(IV) oxides and the gradual formation of bulky oxide aggregates. These aggregates serve as nucleation centers for the formation of Mn oxide micronodules and Mn-rich sediments. A soil-borne Escherichia coli with high Mn(II)-oxidizing activity formed Mn(III)/Mn(IV) oxide deposit layers and aggregates under laboratory culture conditions. We engineered MCO266 onto the cell surfaces of both an activity-negative recipient and wild-type strains. The results confirmed that MCO266 governs Mn(II) oxidation and initiates the formation of deposits and aggregates. By contrast, a cell-free substrate, heat-killed strains, and intracellularly expressed or purified MCO266 failed to catalyze Mn(II) oxidation. However, purified MCO266 exhibited Mn(II)-oxidizing activity when combined with cell outer membrane component (COMC) fractions in vitro. We demonstrated that Mn(II) oxidation and aggregate formation occurred through an oxygen-dependent biotic transformation process that requires a certain minimum Mn(II) concentration. We propose an approximate electron transfer pathway in which MCO266 transfers only one electron to convert Mn(II) to Mn(III) and then cooperates with other COMC electron transporters to transfer the other electron required to oxidize Mn(III) to Mn(IV).

Dissolved Mn(III) in water treatment works: Prevalence and significance.

PubMed

Johnson, Karen L; McCann, Clare M; Wilkinson, John-Luke; Jones, Matt; Tebo, Bradley M; West, Martin; Elgy, Christine; Clarke, Catherine E; Gowdy, Claire; Hudson-Edwards, Karen A

2018-09-01

Dissolved Mn(III) has been identified at all stages throughout a Water Treatment Works (WTW) receiving inflow from a peaty upland catchment in NE England. Ninety percent of the influent total manganese into the WTW is particulate Mn, in the form of Mn oxide (>0.2 μm). Approximately 9% (mean value, n = 22, range of 0-100%) of the dissolved (<0.2 μm) influent Mn is present as dissolved Mn(III). Mn(III) concentrations are highest (mean of 49% of total dissolved Mn; n = 26, range of 17-89%) within the WTW where water comes into contact with the organic-rich sludges which are produced as waste products in the WTW. These Mn(III)-containing wastewaters are recirculated to the head of the works and constitute a large input of Mn(III) into the WTW. This is the first report of Mn(III) being identified in a WTW. The ability of Mn(III) to act as both an oxidant and a reductant is of interest to the water industry. Understanding the formation and removal of Mn(III) within may help reduce Mn oxide deposits in pipe networks. Further understanding how the ratio of Mn(III) to Mn(II) can be used to optimise dissolved Mn removal would save the water industry significant money in reducing discoloration 'events' at the customers' tap. Copyright © 2018. Published by Elsevier Ltd.

Magnetism in Mn-nanowires and -clusters as δ-doped layers in group IV semiconductors (Si, Ge)

NASA Astrophysics Data System (ADS)

Simov, K. R.; Glans, P.-A.; Jenkins, C. A.; Liberati, M.; Reinke, P.

2018-01-01

Mn doping of group-IV semiconductors (Si/Ge) is achieved by embedding nanostructured Mn-layers in group-IV matrix. The Mn-nanostructures are monoatomic Mn-wires or Mn-clusters and capped with an amorphous Si or Ge layer. The precise fabrication of δ-doped Mn-layers is combined with element-specific detection of the magnetic signature with x-ray magnetic circular dichroism. The largest moment (2.5 μB/Mn) is measured for Mn-wires with ionic bonding character and a-Ge overlayer cap; a-Si capping reduces the moment due to variations of bonding in agreement with theoretical predictions. The moments in δ-doped layers dominated by clusters is quenched with an antiferromagnetic component from Mn-Mn bonding.

Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides

NASA Astrophysics Data System (ADS)

Lan, Shuai; Wang, Xiaoming; Xiang, Quanjun; Yin, Hui; Tan, Wenfeng; Qiu, Guohong; Liu, Fan; Zhang, Jing; Feng, Xionghan

2017-08-01

Oxidation of Mn(II) is an important process that controls the mobility and bioavailability of Mn, as well as the formation of Mn (oxyhydr)oxides in natural systems. It was found that the surfaces of minerals, such as iron (oxyhydr)oxides, can accelerate Mn(II) oxidation to a certain degree, but the underlying mechanism has not been clearly understood. This study explores the reaction pathways and mechanisms of Mn(II) oxidation on ferrihydrite surfaces at neutral pH, commonly found in natural environments, by comparisons with montmorillonite, amorphous Al(OH)3, goethite, and magnetite using macroscopic experiments and spectroscopic analyses. Results show that when Mn(II) concentrations are below 4 mM, macroscopic Mn(II) adsorption on the three iron (oxyhydr)oxide surfaces conforms well to the Langmuir equation, with ferrihydrite showing the highest adsorption capacity. With Mn(II) concentrations ranging within 6-24 mM, the adsorbed Mn(II) is mainly oxidized into manganite (γ-MnOOH) and/or feitknechtite (β-MnOOH) by dissolved O2, and Mn(II) removal on a unit mass basis in the presence of magnetite is the highest compared with ferrihydrite and goethite. Ferrihydrite, a semiconductor material, shows stronger catalytic ability for Mn(II) oxidation on the same surface area than insulator minerals (i.e., montmorillonite and amorphous Al(OH)3). Additionally, the products of Mn(II) oxidation in the presence of semiconductor iron (oxyhydr)oxides (i.e., ferrihydrite, goethite, or magnetite) at the same Fe/Mn molar ratio include both manganite and a small amount of Mn(IV) minerals, and the Mn average oxidation states (Mn AOSs) of these products follow the order: magnetite > goethite > ferrihydrite. Magnetite and goethite, with relatively smaller SSAs and lower band gap energies, exhibit greater catalysis for Mn(II) oxidation than ferrihydrite at the same Fe/Mn ratio, which goes against the conventional interfacial effect and is related to the electrochemical properties. Thus, the Mn(II) catalytic oxidation by O2 on ferrihydrite surfaces should include an electrochemical pathway, i.e., electron transfer (ET) in the Mn(II)-Conduction Band (CB)Ferrihydrite-O2 complexes, in addition to the conventional two interfacial catalytic pathways, i.e., ET in the Mn(II)-Fe(II, III)-O2 complexes and direct ET in the Mn(II)-O2 complexes. These results reveal new implications for understanding the processes and mechanisms of Mn(II) oxidation on iron (oxyhydr)oxide surfaces and the abiotic formation of Mn (oxyhydr)oxides in surface environments.

Tunable multiple emissions in manganese-concentrated sulfide through simultaneous tailoring of Mn-site coordination and Mn-Mn pair geometry

NASA Astrophysics Data System (ADS)

Chen, Zitao; Song, Enhai; Ye, Shi; Zhang, Qinyuan

2017-12-01

In contrast to generally single-band visible emission feature from Mn2+, simultaneous visible (VIS) and near-infrared (NIR) multiple emissions are demonstrated in Mn2+ concentrated sulfide (MnS) by only involving a single crystallographic site. Upon varying the Mn2+-site coordination and/or Mn-Mn pairs geometry in different structural MnS, the multiple emissions from divalent manganese can be easily tuned from 575 to 720 nm (VIS) or from 880 to 900 or 1380 nm (NIR), respectively. The excitation spectroscopy and the luminescent decay, together with crystal structural analyses, are employed to investigate the electronic transition and the excited state dynamics of these Mn2+ concentrated systems. It is found that the VIS and NIR emissions can be ascribed to the isolated Mn2+ ion and exchange coupled Mn-Mn pair center, respectively. The effect of crystal field and bridging geometry, as well as temperature on the exchange coupled Mn2+ pairs NIR emissive center, is also investigated in detail. This work not only provides keen insights into the de-excitation pathway of Mn2+-concentrated material, but also offers the possibilities of designing a novel NIR emitting source for various photonic applications.

Naturally occurring levels of elements in fishes as determined by PIXE and XRF methods

NASA Astrophysics Data System (ADS)

Tallandini, L.; Giacobini, F.; Turchetto, M.; Galassini, S.; Liu, Q. X.; Shao, H. R.; Moschini, G.; Moro, R.; Gialanella, G.; Ghermandi, G.; Cecchi, R.; Injuk, J.; Valković, V.

1989-04-01

Naturally occurring levels of S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Sb, Sr and Pb were measured in the gills, liver and muscles of fishes ( Zosterisessor ophiocephalus Pall) in the northwestern region of the Adriatic Sea. The overall performance of PIXE and XRF methods was tested by the analysis of standard reference materials. The mean concentration values for elements were calculated from the distribution of experimentally determined concentration values. The obtained data are discussed in the framework of metal metabolism and toxicology.

Aerodynamics, Dimensions, Inertial Properties, and Performance of Artillery Projectiles

DTIC Science & Technology

1977-01-01

vary in ’*ese characteristics due both’o ru-mn-inv1 chancies r-ade over the years and! changes in the method of r 1a71_1faCtL rf- and of maoufacturer...Aerodynamic Coefficients All of the aerodynamic coefficients presented in this report, except for the XM712 (CLGP), were estimated by the same method and...are pre- sented in the same format. The method used is documented in Reference 22 and is available as a computer program, SPIN73, in FORTRAN. It

An Inexpensive and Easy Ultrasound Phantom: A Novel Use for SPAM.

PubMed

Nolting, Laura; Hunt, Patrick; Cook, Thomas; Douglas, Barton

2016-04-01

Ultrasound models, commonly referred to as "phantoms," are simulation tools for ultrasound education. Commercially produced phantoms are available, but there are "homemade" alternatives such as raw poultry and gelatin molds. Precooked, processed meat, better known as SPAM (Hormel Foods Corporation, Austin, MN), can be used as an ultrasound phantom to teach several ultrasound applications. It is a versatile, hygienic, and easily manipulated medium that does not require refrigeration or preparatory work and can be easily discarded at the end of use. © 2016 by the American Institute of Ultrasound in Medicine.

Calculations of Excitation Functions of Some Structural Fusion Materials for ( n, t) Reactions up to 50 MeV Energy

NASA Astrophysics Data System (ADS)

Tel, E.; Durgu, C.; Aktı, N. N.; Okuducu, Ş.

2010-06-01

Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of ( n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. In this study, ( n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al( n, t)25Mg, 51V( n, t)49Ti, 52Cr( n, t)50V, 55Mn( n, t)53Cr and 56Fe( n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, we have calculated ( n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results are discussed and compared with the experimental data taken from the literature.

Enhanced Cycleability of Amorphous MnO₂ by Covering on α-MnO₂ Needles in an Electrochemical Capacitor.

PubMed

Liu, Quanbing; Ji, Shan; Yang, Juan; Wang, Hui; Pollet, Bruno G; Wang, Rongfang

2017-08-24

An allomorph MnO₂@MnO₂ core-shell nanostructure was developed via a two-step aqueous reaction method. The data analysis of Scanning Electron Microscopy, Transmission Electron Microscopy, X-Ray Diffraction and N₂ adsorption-desorption isotherms experiments indicated that this unique architecture consisted of a porous layer of amorphous-MnO₂ nano-sheets which were well grown onto the surface of α-MnO₂ nano-needles. Cyclic voltammetry experiments revealed that the double-layer charging and Faradaic pseudo -capacity of the MnO₂@MnO₂ capacitor electrode contributed to a specific capacitance of 150.3 F·g -1 at a current density of 0.1 A·g -1 . Long cycle life experiments on the as-prepared MnO₂@MnO₂ sample showed nearly a 99.3% retention after 5000 cycles at a current density of 2 A·g -1 . This retention value was found to be significantly higher than those reported for amorphous MnO₂-based capacitor electrodes. It was also found that the remarkable cycleability of the MnO₂@MnO₂ was due to the supporting role of α-MnO₂ nano-needle core and the outer amorphous MnO₂ layer.

Oxidation of MnO(100) and NaMnO2 formation: Characterization of Mn2+ and Mn3+ surfaces via XPS and water TPD

NASA Astrophysics Data System (ADS)

Feng, Xu; Cox, David F.

2018-09-01

The oxidation of clean and Na precovered MnO(100) has been investigated by X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and temperature programmed desorption (TPD) of adsorbed water. XPS results indicate that Mn3O4-like and Mn2O3-like surfaces can be formed by various oxidation treatments of clean and nearly-stoichiometric MnO(100), while a NaMnO2-like surface can be produced by the oxidation of MnO(100) pre-covered with multilayers of metallic Na. Water TPD results indicate that water adsorption/desorption is sensitive to the available oxidation states of surface Mn cations, and can be used to distinguish between surfaces exposing Mn2+and Mn3+ cations, or a combination of these oxidation states. Carbon dioxide and water TPD results from the NaMnO2-like surface indicate that pre-adsorbed water blocks the uptake of CO2, while water displaces pre-adsorbed CO2. No indication of a strong reactive interaction is observed between CO2, water and the NaMnO2-like surface under the conditions of our study.

Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge compensation†

PubMed Central

Lassalle-Kaiser, Benedikt; Hureau, Christelle; Pantazis, Dimitrios A.; Pushkar, Yulia; Guillot, Régis; Yachandra, Vittal K.; Yano, Junko; Neese, Frank; Anxolabéhère-Mallart, Elodie

2014-01-01

Activation of a water molecule by the electrochemical oxidation of a Mn-aquo complex accompanied by the loss of protons is reported. The sequential (2 × 1 electron/1 proton) and direct (2 electron/2 proton) proton-coupled electrochemical oxidation of a non-porphyrinic six-coordinated Mn(II)OH2 complex into a mononuclear Mn(O) complex is described. The intermediate Mn(III)OH2 and Mn(III)OH complexes are electrochemically prepared and analysed. Complete deprotonation of the coordinated water molecule in the Mn(O) complex is confirmed by electrochemical data while the analysis of EXAFS data reveals a gradual shortening of an Mn–O bond upon oxidation from Mn(II)OH2 to Mn(III)OH and Mn(O). Reactivity experiments, DFT calculations and XANES pre-edge features provide strong evidence that the bonding in Mn(O) is best characterized by a Mn(III)-oxyl description. Such oxyl species could play a crucial role in natural and artificial water splitting reactions. We provide here a synthetic example for such species, obtained by electrochemical activation of a water ligand. PMID:24772190

Effect of (Mn,Cr) co-doping on structural, electronic and magnetic properties of zinc oxide by first-principles studies

NASA Astrophysics Data System (ADS)

Aimouch, D. E.; Meskine, S.; Boukortt, A.; Zaoui, A.

2018-04-01

In this study, structural, electronic and magnetic properties of Mn doped (ZnO:Mn) and (Mn,Cr) co-doped zinc oxide (ZnO:(Mn,Cr)) have been calculated with the FP-LAPW method by using the LSDA and LSDA+U approximations. Going through three configurations of Mn,Cr co-doped ZnO corresponding to three different distances between manganese and chromium, we have analyzed that ZnO:(Mn,Cr) system is more stable in its preferred configuration2. The lattice constant of undoped ZnO that has been calculated in this study is in a good agreement with the experimental and theoretical values. It was found to be increased by doping with Mn or (Mn,Cr) impurities. The band structure calculations showed the metallic character of Mn doped and Mn,Cr co-doped ZnO. As results, by using LSDA+U (U = 6eV), we show the half-metallic character of ZnO:Mn and ZnO:Mn,Cr. We present the calculated exchange couplings d-d of Mn doped ZnO which is in a good agreement with the former FPLO calculation data and the magnetization step measurement of the experimental work. The magnetic coupling between neighboring Mn impurities in ZnO is found to be antiferromagnetic. In the case of (Mn,Cr) co-doped ZnO, the magnetic coupling between Mn and Cr impurities is found to be antiferromagnetic for configuration1 and 3, and ferromagnetic for configuration2. Thus, the ferromagnetic coupling is weak in ZnO:Mn. Chromium co-doping greatly enhance the ferromagnetism, especially when using configuration2. At last, we present the 2D and 3D spin-density distribution of ZnO:Mn and ZnO:(Mn,Cr) where the ferromagnetic state in ZnO:(Mn,Cr) comes from the strong p-d and d-d interactions between 2p-O, 3d-Mn and 3d-Cr electrons. The results of our calculations suggest that the co-doping ZnO(Mn, Cr) can be among DMS behavior for spintronic applications.

The effect of microstructure and strength on the fracture toughness of an 18 Ni, 300 grade maraging steel

NASA Technical Reports Server (NTRS)

Psioda, J. A.; Low, J. R., Jr.

1977-01-01

Fractography and metallographic sectioning were used to investigate the influence of microstructure and strength on the fracture toughness (KIc) and fracture mechanism of an 18 Ni, 300 grade maraging steel. Increased yield strength from 1442 to 2070 MN/m squared through precipitation hardening results in a KIc loss from 143 to 55 MN/m superscript 3/2. Ti (C,N) Ti2S, and TiC inclusions in sizes from 1 to 8, 1 to 15, and 0.1 to 2 microns respectively serve as sites for void nucleation and lead to fracture by the dimpled rupture process in all strength levels considered. TiC nucleated dimples occupy more than half the fracture in all conditions. Void nucleation rate and resultant number of dimples per unit area of fracture increase with increasing yield strength. Average dimple size decreases with increasing strength and/or overaging which follows from the decreasing amount of stable void growth measured by sectioning tensile specimens. Void growth is assisted by crack branching along a path of TiC inclusions. Coalescence occurs in the highest strength materials by a combination of TiC void nucleation and premature separation at strengthening precipitates.

18 CFR 385.103 - References to rules (Rule 103).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false References to rules (Rule 103). 385.103 Section 385.103 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Definitions § 385.103 References to rules (Rule 103). This part cross-references its sections according to...

18 CFR 385.103 - References to rules (Rule 103).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false References to rules (Rule 103). 385.103 Section 385.103 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Definitions § 385.103 References to rules (Rule 103). This part cross-references its sections according to...

Creation of a 3Mn/1Fe cluster in the oxygen-evolving complex of photosystem II and investigation of its functional activity

DOE PAGES

Semin, B. K.; Davletshina, L. N.; Seibert, M.; ...

2017-11-11

Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H 2Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH 5.7) than at neutral pH (3Mn/RC are extracted at pH 6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH 6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]. Here we investigated the efficiency of Mn extraction by Fe(II) at acidic pH and found that Fe(II) cations can extractmore » only 1Mn/RC from PSII(-Ca,4Mn) membranes at pH 5.7, forming a 3Mn/1Fe cluster.« less

Creation of a 3Mn/1Fe cluster in the oxygen-evolving complex of photosystem II and investigation of its functional activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semin, B. K.; Davletshina, L. N.; Seibert, M.

Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H 2Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH 5.7) than at neutral pH (3Mn/RC are extracted at pH 6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH 6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]. Here we investigated the efficiency of Mn extraction by Fe(II) at acidic pH and found that Fe(II) cations can extractmore » only 1Mn/RC from PSII(-Ca,4Mn) membranes at pH 5.7, forming a 3Mn/1Fe cluster.« less

VizieR Online Data Catalog: Nebular [OIII] collision strengths - SS3 (Storey+, 2015)

NASA Astrophysics Data System (ADS)

Storey, P. J.; Sochi, T.

2015-03-01

The data set consists of ten Upsilon files labeled 'up_mn.dat' and ten Downsilon files labeled 'do_mn.dat' where m=1,2,3,4 and n=2,3,4,5 with m

EnviroAtlas - Minneapolis/St. Paul, MN - One Meter Resolution Urban Area Land Cover Map (MULC) (2010)

EPA Pesticide Factsheets

The Minneapolis-St. Paul, MN EnviroAtlas Meter-scale Urban Land Cover (MULC) data were generated from four-band (red, green, blue, and near infrared) aerial photography provided by the United States Department of Agriculture (USDA) National Agricultural Imagery Program (NAIP). The NAIP imagery for the state of Minnesota was collected during the summer and fall of 2010. Lidar data and relevant ancillary datasets contributed to the classification. Eight land cover types were classified: water, impervious surface, soil and barren land, trees and forest, grass and herbaceous, agriculture, woody wetland, and emergent wetland. An accuracy assessment of 644 completely random and 62 stratified random photointerpreted reference points yielded an overall User's Accuracy of 83 percent. The boundary of this data layer is delineated by the US Census Bureau's 2010 Urban Statistical Area for Minneapolis-St. Paul, MN plus a 1-km buffer. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associat

Environmental implications of high metal content in soils of a titanium mining zone in Kenya.

PubMed

Maina, David M; Ndirangu, Douglas M; Mangala, Michael M; Boman, Johan; Shepherd, Keith; Gatari, Michael J

2016-11-01

Mining activities contribute to an increase of specific metal contaminants in soils. This may adversely affect plant life and consequently impact on animal and human health. The objective of this study was to obtain the background metal concentrations in soils around the titanium mining in Kwale County for monitoring its environmental impacts. Forty samples were obtained with half from topsoils and the other from subsoils. X-ray fluorescence spectrometry was used to determine the metal content of the soil samples. High concentrations of Ti, Mn, Fe, and Zr were observed where Ti concentrations ranged from 0.47 to 2.8 %; Mn 0.02 to 3.1 %; Fe 0.89 to 3.1 %; and Zr 0.05 to 0.85 %. Using ratios of elemental concentrations in topsoil to subsoil method and enrichment factors concept, the metals were observed to be of geogenic origin with no anthropogenic input. The high concentrations of Mn and Fe may increase their concentration levels in the surrounding agricultural lands through deposition, thereby causing contamination on the land and the cultivated food crops. The latter can cause adverse human health effects. In addition, titanium mining will produce tailings containing low-level titanium concentrations, which will require proper disposal to avoid increasing titanium concentrations in the soils of the region since it has been observed to be phytotoxic to plants at high concentrations. The results of this study will serve as reference while monitoring the environmental impact by the titanium mining activities.

Membrane solid phase microextraction with alumina hollow fiber on line coupled with ICP-OES for the determination of trace copper, manganese and nickel in environmental water samples.

PubMed

Cui, Chao; He, Man; Hu, Bin

2011-03-15

A novel alumina hollow fiber was synthesized by sol-gel template method and was characterized by scanning electron microscopy, N(2) adsorption technique and X-ray diffraction. With the use of prepared alumina hollow fiber as extraction membrane, a new method of flow injection (FI)-membrane solid phase microextraction (MSPME) on-line coupled to inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for simultaneous determination of trace metals (Cu, Mn and Ni) in environmental water samples. The adsorption capacities of the alumina hollow fiber for Cu, Mn and Ni were found to be 6.6, 8.7 and 13.3 mg g(-1), respectively. With a preconcentration factor of 10, the limits of detection (LODs) for Cu, Mn and Ni were found to be 0.88, 0.61 and 0.38 ng mL(-1), respectively, and the relative standard deviations (RSDs) were ranging from 6.2 to 7.9% (n = 7, c = 10 ng mL(-1)). To validate the accuracy, the proposed method was applied to the analysis of certified reference material GSBZ50009-88 environmental water and the determined values are in good agreement with the certified values. The developed method was also employed for the analysis of Yangtze River water and East Lake water, and the recoveries for the spiked samples were in the range of 87.4-110.2%. Copyright © 2011 Elsevier B.V. All rights reserved.

Manganese speciation of laboratory-generated welding fumes

PubMed Central

Andrews, Ronnee N.; Keane, Michael; Hanley, Kevin W.; Feng, H. Amy; Ashley, Kevin

2015-01-01

The objective of this laboratory study was to identify and measure manganese (Mn) fractions in chamber-generated welding fumes (WF) and to evaluate and compare the results from a sequential extraction procedure for Mn fractions with that of an acid digestion procedure for measurement of total, elemental Mn. To prepare Mn-containing particulate matter from representative welding processes, a welding system was operated in short circuit gas metal arc welding (GMAW) mode using both stainless steel (SS) and mild carbon steel (MCS) and also with flux cored arc welding (FCAW) and shielded metal arc welding (SMAW) using MCS. Generated WF samples were collected onto polycarbonate filters before homogenization, weighing and storage in scintillation vials. The extraction procedure consisted of four sequential steps to measure various Mn fractions based upon selective solubility: (1) soluble Mn dissolved in 0.01 M ammonium acetate; (2) Mn (0,II) dissolved in 25 % (v/v) acetic acid; (3) Mn (III,IV) dissolved in 0.5% (w/v) hydroxylamine hydrochloride in 25% (v/v) acetic acid; and (4) insoluble Mn extracted with concentrated hydrochloric and nitric acids. After sample treatment, the four fractions were analyzed for Mn by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). WF from GMAW and FCAW showed similar distributions of Mn species, with the largest concentrations of Mn detected in the Mn (0,II) and insoluble Mn fractions. On the other hand, the majority of the Mn content of SMAW fume was detected as Mn (III,IV). Although the concentration of Mn measured from summation of the four sequential steps was statistically significantly different from that measured from the hot block dissolution method for total Mn, the difference is small enough to be of no practical importance for industrial hygiene air samples, and either method may be used for Mn measurement. The sequential extraction method provides valuable information about the oxidation state of Mn in samples and allows for comparison to results from previous work and from total Mn dissolution methods. PMID:26345630

Manganese speciation of laboratory-generated welding fumes.

PubMed

Andrews, Ronnee N; Keane, Michael; Hanley, Kevin W; Feng, H Amy; Ashley, Kevin

The objective of this laboratory study was to identify and measure manganese (Mn) fractions in chamber-generated welding fumes (WF) and to evaluate and compare the results from a sequential extraction procedure for Mn fractions with that of an acid digestion procedure for measurement of total, elemental Mn. To prepare Mn-containing particulate matter from representative welding processes, a welding system was operated in short circuit gas metal arc welding (GMAW) mode using both stainless steel (SS) and mild carbon steel (MCS) and also with flux cored arc welding (FCAW) and shielded metal arc welding (SMAW) using MCS. Generated WF samples were collected onto polycarbonate filters before homogenization, weighing and storage in scintillation vials. The extraction procedure consisted of four sequential steps to measure various Mn fractions based upon selective solubility: (1) soluble Mn dissolved in 0.01 M ammonium acetate; (2) Mn (0,II) dissolved in 25 % (v/v) acetic acid; (3) Mn (III,IV) dissolved in 0.5% (w/v) hydroxylamine hydrochloride in 25% (v/v) acetic acid; and (4) insoluble Mn extracted with concentrated hydrochloric and nitric acids. After sample treatment, the four fractions were analyzed for Mn by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). WF from GMAW and FCAW showed similar distributions of Mn species, with the largest concentrations of Mn detected in the Mn (0,II) and insoluble Mn fractions. On the other hand, the majority of the Mn content of SMAW fume was detected as Mn (III,IV). Although the concentration of Mn measured from summation of the four sequential steps was statistically significantly different from that measured from the hot block dissolution method for total Mn, the difference is small enough to be of no practical importance for industrial hygiene air samples, and either method may be used for Mn measurement. The sequential extraction method provides valuable information about the oxidation state of Mn in samples and allows for comparison to results from previous work and from total Mn dissolution methods.

Early Childhood Education: Organization of Reference Topics for Use in Undergraduate Courses. ERIC 1967-Spring 1973. (A Selective Listing).

ERIC Educational Resources Information Center

Wallat, Cynthia, Comp.

This selective bibliography cites references pertaining to early childhood education from "Research in Education" (RIE) and "Current Index to Journals in Education" (CIJE). The bibliography is divided into three sections. The first two sections contain references from RIE and CIJE from spring 1967 through spring 1973; the last section updates the…