540 On W---- Gr-h-m Esq: of M-sskn-w

Burns, Robert

doi:10.1093/oseo/instance.00044359

Cited by 36 publications

(44 citation statements)

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“…The collapse presumably involves the loss of a water layer and is irreversible. The natural phase that is the presumed analogue of the synthetic 10 Å material has been called buserite (not an approved mineral name) (96)(97)(98) and might be a common component of ocean Mn nodules before they dry out (99,100). Cations such as Ni(II), Mg(II), Ca(II), and Co(II) tend to stabilize the buserite structure against collapse (101,102).…”

Section: Mn Oxide Minerals With Layer Structuresmentioning

confidence: 99%

Manganese oxide minerals: Crystal structures and economic and environmental significance

Post

1999

Proc. Natl. Acad. Sci. U.S.A.

1,550

1,182

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Manganese oxide minerals have been used for thousands of years-by the ancients for pigments and to clarify glass, and today as ores of Mn metal, catalysts, and battery material. More than 30 Mn oxide minerals occur in a wide variety of geological settings. They are major components of Mn nodules that pave huge areas of the ocean f loor and bottoms of many fresh-water lakes. Mn oxide minerals are ubiquitous in soils and sediments and participate in a variety of chemical reactions that affect groundwater and bulk soil composition. Their typical occurrence as fine-grained mixtures makes it difficult to study their atomic structures and crystal chemistries. In recent years, however, investigations using transmission electron microscopy and powder x-ray and neutron diffraction methods have provided important new insights into the structures and properties of these materials. The crystal structures for todorokite and birnessite, two of the more common Mn oxide minerals in terrestrial deposits and ocean nodules, were determined by using powder x-ray diffraction data and the Rietveld refinement method. Because of the large tunnels in todorokite and related structures there is considerable interest in the use of these materials and synthetic analogues as catalysts and cation exchange agents. Birnessite-group minerals have layer structures and readily undergo oxidation reduction and cation-exchange reactions and play a major role in controlling groundwater chemistry.

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Section: Mn Oxide Minerals With Layer Structuresmentioning

confidence: 99%

Manganese oxide minerals: Crystal structures and economic and environmental significance

Post

1999

Proc. Natl. Acad. Sci. U.S.A.

1,550

1,182

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“…The mineralogy of manganese oxides formed in lakes and oceans by oxi dative precipitation is still an active field of research with sometimes intense discussions [e.g., the todorokite-buserite problem (20)(21)(22)]. Laboratory stud ies of abiotic Mn(II) oxidation at pH 9 yielded Mn3 04 (hausmannite) as the initial product.…”

Section: Wehrli Et Al μη Oxidation At Sediment-water Interfacementioning

confidence: 99%

Reaction Rates and Products of Manganese Oxidation at the Sediment-Water Interface

Wehrli

Friedl

Manceau

1995

Advances in Chemistry

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Manganese(II) oxidation rates in a eutrophiclake were calculated from a 4-year record of sediment-trap data, and the structure of the pre vailing manganese oxides were determined by extended X-ray absorp tion fine structure (EXAFS) spectroscopy. The oxidation rate near the sediment surface showed a distinct seasonal pattern, with maxima of up to 2.8 mmol/m 2 per day during summer. The average half-life of Mn(II) during stagnation in summer was 1.4 days. A review of pub lished oxidation rates showed that this half-life, which cannot be ex plained with available data of abiotic surface catalysis, is within the typical range of microbiological oxidation. EXAFS revealed that the oxidation product consists mainly of vernadite (δ-MnO2), an X-ray -amorphous Mn(IV) oxide. INTEREST IN THE AQUATIC REDOX CHEMISTRY of manganese is at least as old as Werner Stumms scientific career. The first Ph.D. student in his laboratory at Harvard University worked on the chemistry of aqueous Mn(II) and Mn(IV) (J). Since then aquatic chemists have refined their analytical tools (2), their conceptual (3) and numerical (4) models of manganese cycling, and their understanding of heterogeneous redox reactions in general (5,6). This chapter examines the biogeochemical and mineralogical aspects of the manganese re-OO65-2393/95/0244-Olll$O8.72/O

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“…Since H . influenzae may flourish in the respiratory tract despite systemic antibody (14) lymphocytes sensitized to H . influenzae somatic antigen could confer beneficial cellular immunity in these sites.…”

Section: Resultsmentioning

confidence: 99%

Transformation of Human Lymphocytes by Haemophilus influenzae Somatic and Polysaccharide Antigens

Alford¹

1973

Experimental Biology and Medicine

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540 On W---- Gr-h-m Esq: of M-sskn-w

Cited by 36 publications

References 0 publications

Manganese oxide minerals: Crystal structures and economic and environmental significance

Manganese oxide minerals: Crystal structures and economic and environmental significance

Reaction Rates and Products of Manganese Oxidation at the Sediment-Water Interface

Transformation of Human Lymphocytes by Haemophilus influenzae Somatic and Polysaccharide Antigens

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