Manganese (II) induces chemical hypoxia by inhibiting HIF-prolyl hydroxylase: Implication in manganese-induced pulmonary inflammation

International Nuclear Information System (INIS)

Han, Jeongoh; Lee, Jong-Suk; Choi, Daekyu; Lee, Youna; Hong, Sungchae; Choi, Jungyun; Han, Songyi; Ko, Yujin; Kim, Jung-Ae; Mi Kim, Young; Jung, Yunjin

2009-01-01

Manganese (II), a transition metal, causes pulmonary inflammation upon environmental or occupational inhalation in excess. We investigated a potential molecular mechanism underlying manganese-induced pulmonary inflammation. Manganese (II) delayed HIF-1α protein disappearance, which occurred by inhibiting HIF-prolyl hydroxylase (HPH), the key enzyme for HIF-1α hydroxylation and subsequent von Hippel-Lindau(VHL)-dependent HIF-1α degradation. HPH inhibition by manganese (II) was neutralized significantly by elevated dose of iron. Consistent with this, the induction of cellular HIF-1α protein by manganese (II) was abolished by pretreatment with iron. Manganese (II) induced the HIF-1 target gene involved in pulmonary inflammation, vascular endothelial growth factor (VEGF), in lung carcinoma cell lines. The induction of VEGF was dependent on HIF-1. Manganese-induced VEGF promoted tube formation of HUVEC. Taken together, these data suggest that HIF-1 may be a potential mediator of manganese-induced pulmonary inflammation

Effect of manganese on neonatal rat: manganese distribution in vital organs

Energy Technology Data Exchange (ETDEWEB)

Husain, R; Mushtaq, M; Seth, P K; Chandra, S V

1976-01-01

At present very little is known about the effect of manganese on the early stage of life, though the metal poisoning in adult humans and experimental animals has been known for quite some time. The possibility of the exposure of the general public to the deleterious effects of the metal through the environmental contamination resulting from its increasing industrial applications, and the use of Methyl Cyclopentadienyl Manganese Tricarbonyl (MMT) in gasoline and motor fuel, points to the need for such an information. Our recent studies in this direction have shown that manganese exposed nursing dams can transfer significant amounts of the metal via maternal milk of their sucklings and the brain of the latter exhibited marked enzymatic alterations. The present communication deals with the distribution of manganese in the vital organs of rat pups nursing on mothers receiving the metal orally.

Effect of manganese on neonatal rat: manganese concentration and enzymatic alterations in brain

Energy Technology Data Exchange (ETDEWEB)

Seth, P K; Husain, R; Mushtaq, M; Chandra, S V

1977-01-01

Suckling rats were exposed for 15 and 30 days to manganese through the milk of nursing dams receiving 15 mg MnCl/sub 2/.4H/sub 2/O/kg/day orally and after which the neurological manifestations of metal poisoning were studied. No significant differences in the growth rate, developmental landmarks and walking movements were observed between the control and manganese-exposed pups. The metal concentration was significantly increased in the brain of manganese-fed pups at 15 days and exhibited a further three-fold increase over the control, at 30 days. The accumulation of the metal in the brain of manganese-exposed nursing dams was comparatively much less. A significant decrease in succinic dehydrogenase, adenosine triphosphatase, adenosine deaminase, acetylcholine esterase and an increase in monoamine oxidase activity was observed in the brain of experimental pups and dams. The results suggest that the developing brain may also be susceptible to manganese.

Old age and gender influence the pharmacokinetics of inhaled manganese sulfate and manganese phosphate in rats

International Nuclear Information System (INIS)

Dorman, David C.; McManus, Brian E.; Marshall, Marianne W.; James, R. Arden; Struve, Melanie F.

2004-01-01

In this study, we examined whether gender or age influences the pharmacokinetics of manganese sulfate (MnSO 4 ) or manganese phosphate (as the mineral form hureaulite). Young male and female rats and aged male rats (16 months old) were exposed 6 h day -1 for 5 days week -1 to air, MnSO 4 (at 0.01, 0.1, or 0.5 mg Mn m -3 ), or hureaulite (0.1 mg Mn m -3 ). Tissue manganese concentrations were determined in all groups at the end of the 90-day exposure and 45 days later. Tissue manganese concentrations were also determined in young male rats following 32 exposure days and 91 days after the 90-day exposure. Intravenous 54 Mn tracer studies were also performed in all groups immediately after the 90-day inhalation to assess whole-body manganese clearance rates. Gender and age did not affect manganese delivery to the striatum, a known target site for neurotoxicity in humans, but did influence manganese concentrations in other tissues. End-of-exposure olfactory bulb, lung, and blood manganese concentrations were higher in young male rats than in female or aged male rats and may reflect a portal-of-entry effect. Old male rats had higher testis but lower pancreas manganese concentrations when compared with young males. Young male and female rats exposed to MnSO 4 at 0.5 mg Mn m -3 had increased 54 Mn clearance rates when compared with air-exposed controls, while senescent males did not develop higher 54 Mn clearance rates. Data from this study should prove useful in developing dosimetry models for manganese that consider age or gender as potential sensitivity factors

Characterization of Sumbawa manganese ore and recovery of manganese sulfate as leaching products

Science.gov (United States)

Kusumaningrum, Retno; Rahmani, Siti Astari; Widayatno, Wahyu Bambang; Wismogroho, Agus Sukarto; Nugroho, Dwi Wahyu; Maulana, Syahrizal; Rochman, Nurul Taufiqu; Amal, M. Ikhlasul

2018-05-01

The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate.

Relationship-Oriented Software Defined AS-Level Fast Rerouting for Multiple Link Failures

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Chunxiu Li

2015-01-01

Full Text Available Large-scale deployments of mission-critical services have led to stringent demands on Internet routing, but frequently occurring network failures can dramatically degrade the network performance. However, Border Gateway Protocol (BGP can not react quickly to recover from them. Although extensive research has been conducted to deal with the problem, the multiple failure scenarios have never been properly addressed due to the limit of distributed control plane. In this paper, we propose a local fast reroute approach to effectively recover from multiple link failures in one administrative domain. The principle of Software Defined Networking (SDN is used to achieve the software defined AS-level fast rerouting. Considering AS relationships, efficient algorithms are proposed to automatically and dynamically find protection paths for multiple link failures; then OpenFlow forwarding rules are installed on routers to provide data forwarding continuity. Our approach is able to ensure applicability to ASes with flexibility and adaptability to multiple link failures, contributing toward improving the network performance. Through experimental results, we show that our proposal provides effective failure recovery and does not introduce significant control overhead to the network.

Sub-chronic inhalation of high concentrations of manganese sulfate induces lower airway pathology in rhesus monkeys

Directory of Open Access Journals (Sweden)

Wong Brian A

2005-10-01

Full Text Available Abstract Background Neurotoxicity and pulmonary dysfunction are well-recognized problems associated with prolonged human exposure to high concentrations of airborne manganese. Surprisingly, histological characterization of pulmonary responses induced by manganese remains incomplete. The primary objective of this study was to characterize histologic changes in the monkey respiratory tract following manganese inhalation. Methods Subchronic (6 hr/day, 5 days/week inhalation exposure of young male rhesus monkeys to manganese sulfate was performed. One cohort of monkeys (n = 4–6 animals/exposure concentration was exposed to air or manganese sulfate at 0.06, 0.3, or 1.5 mg Mn/m3 for 65 exposure days. Another eight monkeys were exposed to manganese sulfate at 1.5 mg Mn/m3 for 65 exposure days and held for 45 or 90 days before evaluation. A second cohort (n = 4 monkeys per time point was exposed to manganese sulfate at 1.5 mg Mn/m3 and evaluated after 15 or 33 exposure days. Evaluations included measurement of lung manganese concentrations and evaluation of respiratory histologic changes. Tissue manganese concentrations were compared for the exposure and control groups by tests for homogeneity of variance, analysis of variance, followed by Dunnett's multiple comparison. Histopathological findings were evaluated using a Pearson's Chi-Square test. Results Animals exposed to manganese sulfate at ≥0.3 mg Mn/m3 for 65 days had increased lung manganese concentrations. Exposure to manganese sulfate at 1.5 mg Mn/m3 for ≥15 exposure days resulted in increased lung manganese concentrations, mild subacute bronchiolitis, alveolar duct inflammation, and proliferation of bronchus-associated lymphoid tissue. Bronchiolitis and alveolar duct inflammatory changes were absent 45 days post-exposure, suggesting that these lesions are reversible upon cessation of subchronic high-dose manganese exposure. Conclusion High-dose subchronic manganese sulfate inhalation is

Treating electrolytic manganese residue with alkaline additives for stabilizing manganese and removing ammonia

Energy Technology Data Exchange (ETDEWEB)

Zhou, Changbo; Wang, Jiwei [Chinese Research Academy of Environmental Sciences, Beijing (China); Wang, Nanfang [Hunan Institute of Engineering, Xiangtan (China)

2013-11-15

Electrolytic manganese residue (EMR) from the electrolytic manganese industry is a solid waste containing mainly calcium sulfate dihydrate and quartzite. It is impossible to directly use the EMR as a building material due to some contaminants such as soluble manganese, ammonia nitrogen and other toxic substances. To immobilize the contaminants and reduce their release into the environment, treating EMR using alkaline additives for stabilizing manganese and removing ammonia was investigated. The physical and chemical characteristics of the original EMR were characterized by XRFS, XRD, and SEM. Leaching test of the original EMR shows that the risks to the environment are the high content of soluble manganese and ammonia nitrogen. The influence of various alkaline additives, solidifying reaction time, and other solidifying reaction conditions such as outdoor ventilation and sunlight, and rain flow on the efficiencies of Mn{sup 2+} solidification and ammonia nitrogen removal was investigated. The results show that with mass ratio of CaO to residue 1 : 8, when the solidifying reaction was carried out indoors for 4 h with no rain flow, the highest efficiencies of Mn{sup 2+} solidification and ammonia nitrogen removal (99.98% and 99.21%) are obtained. Leaching test shows that the concentration and emission of manganese and ammonia nitrogen of the treated EMR meets the requirements of the Chinese government legislation (GB8978-1996)

Treating electrolytic manganese residue with alkaline additives for stabilizing manganese and removing ammonia

International Nuclear Information System (INIS)

Zhou, Changbo; Wang, Jiwei; Wang, Nanfang

2013-01-01

Electrolytic manganese residue (EMR) from the electrolytic manganese industry is a solid waste containing mainly calcium sulfate dihydrate and quartzite. It is impossible to directly use the EMR as a building material due to some contaminants such as soluble manganese, ammonia nitrogen and other toxic substances. To immobilize the contaminants and reduce their release into the environment, treating EMR using alkaline additives for stabilizing manganese and removing ammonia was investigated. The physical and chemical characteristics of the original EMR were characterized by XRFS, XRD, and SEM. Leaching test of the original EMR shows that the risks to the environment are the high content of soluble manganese and ammonia nitrogen. The influence of various alkaline additives, solidifying reaction time, and other solidifying reaction conditions such as outdoor ventilation and sunlight, and rain flow on the efficiencies of Mn"2"+ solidification and ammonia nitrogen removal was investigated. The results show that with mass ratio of CaO to residue 1 : 8, when the solidifying reaction was carried out indoors for 4 h with no rain flow, the highest efficiencies of Mn"2"+ solidification and ammonia nitrogen removal (99.98% and 99.21%) are obtained. Leaching test shows that the concentration and emission of manganese and ammonia nitrogen of the treated EMR meets the requirements of the Chinese government legislation (GB8978-1996)

Mineral resource of the month: manganese

Science.gov (United States)

Corathers, Lisa A.

2012-01-01

Manganese is a silver-colored metal resembling iron and often found in conjunction with iron. The earliest-known human use of manganese compounds was in the Stone Age, when early humans used manganese dioxide as pigments in cave paintings. In ancient Rome and Egypt, people started using it to color or remove the color from glass - a practice that continued to modern times. Today, manganese is predominantly used in metallurgical applications as an alloying addition, particularly in steel and cast iron production. Steel and cast iron together provide the largest market for manganese (historically 85 to 90 percent), but it is also alloyed with nonferrous metals such as aluminum and copper. Its importance to steel cannot be overstated, as almost all types of steel contain manganese and could not exist without it.

The scavenging of silver by manganese and iron oxides in stream sediments collected from two drainage areas of Colorado

Science.gov (United States)

Chao, T.T.; Anderson, B.J.

1974-01-01

Stream sediments of two well-weathered and aerated drainage areas of Colorado containing anomalous amounts of silver were allowed to react by shaking with nitric acid of different concentrations (1-10M). Silver, manganese, and iron simultaneously dissolved were determined by atomic absorption. The relationship between silver dissolution and the dissolution of manganese and/or iron was evaluated by linear and multiple regression analyses. The highly significant correlation coefficient (r = 0.913) between silver and manganese dissolution suggests that manganese oxides are the major control on the scavenging of silver in these stream sediments, whereas iron oxides only play a secondary role in this regard. ?? 1974.

Dietary manganese in the Glasgow area

International Nuclear Information System (INIS)

Cross, J.D.; Dale, I.M.; Raie, R.M.

1979-01-01

The manganese content of the diet and human tissue (adult and infant) in the Glasgow area is established. The total manganese intake by a breast fed infant (6 μg/day) is very much lower than that of an adult (5 mg/day). This does not appear to cause any upset in the infant's metabolism and the tissue levels of both groups are similar. This indicates that the human system can obtain its required manganese from both levels of intake. Tea is the major source of manganese in the diet: tobacco, which is rich in manganese, does not contribute a significant amount when smoked. (author)

Defining Multiple Chronic Conditions for Quality Measurement.

Science.gov (United States)

Drye, Elizabeth E; Altaf, Faseeha K; Lipska, Kasia J; Spatz, Erica S; Montague, Julia A; Bao, Haikun; Parzynski, Craig S; Ross, Joseph S; Bernheim, Susannah M; Krumholz, Harlan M; Lin, Zhenqiu

2018-02-01

Patients with multiple chronic conditions (MCCs) are a critical but undefined group for quality measurement. We present a generally applicable systematic approach to defining an MCC cohort of Medicare fee-for-service beneficiaries that we developed for a national quality measure, risk-standardized rates of unplanned admissions for Accountable Care Organizations. To define the MCC cohort we: (1) identified potential chronic conditions; (2) set criteria for cohort conditions based on MCC framework and measure concept; (3) applied the criteria informed by empirical analysis, experts, and the public; (4) described "broader" and "narrower" cohorts; and (5) selected final cohort with stakeholder input. Subjects were patients with chronic conditions. Participants included 21.8 million Medicare fee-for-service beneficiaries in 2012 aged 65 years and above with ≥1 of 27 Medicare Chronic Condition Warehouse condition(s). In total, 10 chronic conditions were identified based on our criteria; 8 of these 10 were associated with notably increased admission risk when co-occurring. A broader cohort (2+ of the 8 conditions) included 4.9 million beneficiaries (23% of total cohort) with an admission rate of 70 per 100 person-years. It captured 53% of total admissions. The narrower cohort (3+ conditions) had 2.2 million beneficiaries (10%) with 100 admissions per 100 person-years and captured 32% of admissions. Most stakeholders viewed the broader cohort as best aligned with the measure concept. By systematically narrowing chronic conditions to those most relevant to the outcome and incorporating stakeholder input, we defined an MCC admission measure cohort supported by stakeholders. This approach can be used as a model for other MCC outcome measures.

Evidence for polaron conduction in nanostructured manganese ferrite

International Nuclear Information System (INIS)

Gopalan, E Veena; Anantharaman, M R; Malini, K A; Saravanan, S; Kumar, D Sakthi; Yoshida, Yasuhiko

2008-01-01

Nanoparticles of manganese ferrite were prepared by the chemical co-precipitation technique. The dielectric parameters, namely, real and imaginary dielectric permittivity (ε' and ε-prime), ac conductivity (σ ac ) and dielectric loss tangent (tanδ), were measured in the frequency range of 100 kHz-8 MHz at different temperatures. The variations of dielectric dispersion (ε') and dielectric absorption (ε-prime) with frequency and temperature were also investigated. The variation of dielectric permittivity with frequency and temperature followed the Maxwell-Wagner model based on interfacial polarization in consonance with Koops phenomenological theory. The dielectric loss tangent and hence ε-prime exhibited a relaxation at certain frequencies and at relatively higher temperatures. The dispersion of dielectric permittivity and broadening of the dielectric absorption suggest the possibility of a distribution of relaxation time and the existence of multiple equilibrium states in manganese ferrite. The activation energy estimated from the dielectric relaxation is found to be high and is characteristic of polaron conduction in the nanosized manganese ferrite. The ac conductivity followed a power law dependence σ ac = Bω n typical of charge transport assisted by a hopping or tunnelling process. The observed minimum in the temperature dependence of the frequency exponent n strongly suggests that tunnelling of the large polarons is the dominant transport process

A simple route to synthesize manganese germanate nanorods

International Nuclear Information System (INIS)

Pei, L.Z.; Yang, Y.; Yuan, C.Z.; Duan Taike; Zhang Qianfeng

2011-01-01

Manganese germanate nanorods have been synthesized by a simple route using germanium dioxide and manganese acetate as the source materials. X-ray diffraction observation shows that the nanorods are composed of orthorhombic and monoclinic manganese germanate phases. Scanning electron microscopy and transmission electron microscopy observations display that the manganese germanate nanorods have flat tips with the length of longer than 10 micrometers and diameter of 60-350 nm, respectively. The role of the growth conditions on the formation of the manganese germanate nanorods shows that the proper selection and combination of the growth conditions are the key factor for controlling the formation of the manganese germanate nanorods. The photoluminescence spectrum of the manganese germanate nanorods exhibits four fluorescence emission peaks centered at 422 nm, 472 nm, 487 nm and 530 nm showing the application potential for the optical devices. - Research Highlights: → Manganese germanate nanorods have been synthesized by simple hydrothermal process. → The formation of manganese germanate nanorods can be controlled by growth conditions. → Manganese germanate nanorods exhibit good PL emission ability for optical device.

Battery recycling: recovery of manganese in the form of electrolytic manganese dioxide

International Nuclear Information System (INIS)

Roriz, Elizabeth Rodrigues Rangel; Von Krüge, Paulo; Espinosa, Denise Crocce Romano; Tenorio, Jorge Alberto Soares

2010-01-01

This work seeks to verify the possibility of using depleted batteries as a source of manganese applying the electrolytic process, considering the growing demand for products containing manganese in their composition. It was used an electrolyte solution containing the metal ions: Ca (270mg / L), Ni (3000 mg / L), Co (630 mg / L), Mn (115.300 mg / L) , Ti (400 mg / L) and Pb (20 mg / L) in concentrated sulfuric acid. The production of electrolytic manganese dioxide (EMD) was performed through galvanization using a stabilized source that monitored the potential of the working electrode. It was used an electrode of lead and two counter electrodes of graphite at a temperature of 98 deg C (± 2 deg C) and current density of 1.69A.dm"-"2. The material obtained was analyzed through the process of X-ray fluorescence spectrometry and X-ray diffraction. The results indicated that it is possible to obtain electrolytic manganese dioxide with a purity of about 94% and that the main allotropic variety obtained under the conditions of the experiment was the ε-MnO_2. (author)

21 CFR 582.5446 - Manganese chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese chloride. 582.5446 Section 582.5446 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5446 Manganese chloride. (a) Product. Manganese chloride. (b) Conditions of use. This...

Fatal manganese intoxication due to an error in the elaboration of Epsom salts for a liver cleansing diet.

Science.gov (United States)

Sánchez, Baltasar; Casalots-Casado, Jaume; Quintana, Salvador; Arroyo, Amparo; Martín-Fumadó, Carles; Galtés, Ignasi

2012-11-30

We describe the case of a 50-year-old man with a fatal intoxication after accidental massive oral ingestion of manganese. The patient presented with lethargy, diffuse abdominal pain, vomiting, and profuse diarrhea after ingesting Epsom salts (magnesium sulfate heptahydrate) during a liver cleansing diet. Despite intensive care management with intubation, prone position ventilation, continuous venovenous hemofiltration, and multiple transfusions, he progressed to refractory shock with multiple organ dysfunction resulting in death within 72 h. Similar patients arrived at several hospitals with identical epidemiology (all had ingested the same salt obtained in the same place). Clinical and forensic investigations (X-ray diffraction) discovered that the supplier had mistakenly prepared the salts with hydrated manganese sulfate instead of magnesium sulfate heptahydrate. The results enabled the other patients to be successfully treated for hydrated manganese sulfate intoxication with life support in the intensive care unit and chelation therapy (EDTA). We describe the clinical presentation of acute manganese poisoning and alert professionals to the risk of an increasingly popular diet. This case demonstrates the importance of collaboration between clinicians, pathologists, and forensic scientists to resolve a difficult-to-diagnose case. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Manganese binding proteins in human and cow's milk

International Nuclear Information System (INIS)

Loennerdal, B.; Keen, C.L.; Hurley, L.S.

1985-01-01

Manganese nutrition in the neonatal period is poorly understood, due in part to a lack of information on the amount of manganese in infant foods and its bioavailability. Since the molecular localization of an element in foods is one determinant of its subsequent bioavailability, a study was made of the binding of manganese in human and cow's milk. An extrinsic label of 54 Mn was shown to equilibrate isotopically with native manganese in milks and formulas. Milk samples were separated into fat, casein and whey by ultracentrifugation. In human milk, the major part (71%) of manganese was found in whey, 11% in casein and 18% in the lipid fraction. In contrast, in cow's milk, 32% of total manganese was in whey, 67% in casein and 1% in lipid. Within the human whey fraction, most of the manganese was bound to lactoferrin, while in cow's whey, manganese was mostly complexed to ligands with molecular weights less than 200. The distribution of manganese in formulas was closer to that of human milk than of cow's milk. The bioavailability of manganese associated with lactoferrin, casein and low molecular weight complexes needs to be assessed

Autonomic function in manganese alloy workers

Energy Technology Data Exchange (ETDEWEB)

Barrington, W.W.; Angle, C.R.; Willcockson, N.K.; Padula, M.A. [Univ. of Nebraska Medical Center, Omaha, NE (United States); Korn, T.

1998-07-01

The observation of orthostatic hypotension in an index case of manganese toxicity lead to this prospective attempt to evaluate cardiovascular autonomic function and cognitive and emotional neurotoxicity in eight manganese alloy welders and machinists. The subjects consisted of a convenience sample consisting of an index case of manganese dementia, his four co-workers in a frog shop for gouging, welding, and grinding repair of high manganese railway track and a convenience sample of three mild steel welders with lesser manganese exposure also referred because of cognitive or autonomic symptoms. Frog shop air manganese samples 9.6--10 years before and 1.2--3.4 years after the diagnosis of the index case exceeded 1.0 mg/m{sup 3} in 29% and 0.2 mg/m{sup 3} in 62%. Twenty-four-hour electrocardiographic (Holter) monitoring was used to determine the temporal variability of the heartrate (RR{prime} interval) and the rates of change at low frequency and high frequency. MMPI and MCMI personality assessment and short-term memory, figure copy, controlled oral word association, and symbol digit tests were used.

21 CFR 184.1446 - Manganese chloride.

Science.gov (United States)

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...

Biological removal of iron and manganese in rapid sand filters - Process understanding of iron and manganese removal

DEFF Research Database (Denmark)

Lin, Katie

to precipitation and corrosion. Manganese and iron can either be removed physico-chemically or biologically or combined. The physico-chemical oxidation and precipitation of manganese can theoretically be achieved by aeration, but this process is slow unless pH is raised far above neutral, making the removal...... of manganese by simple aeration and precipitation under normal drinking water treatment conditions insignificant. Manganese may also be oxidized autocatalytically. Iron is usually easier to remove. First, iron is rapidly chemically oxidized by oxygen at neutral pH followed by precipitation and filtration......-filter, where iron is removed. Step 2: Filtration in an after-filter where e.g. ammonium and manganese is removed. The treatment relies on microbial processes and may present an alternative, greener and more sustainable approach for drinking water production spending less chemicals and energy than chemical (e...

Facile N...N coupling of manganese(V) imido species.

Science.gov (United States)

Yiu, Shek-Man; Lam, William W Y; Ho, Chi-Ming; Lau, Tai-Chu

2007-01-31

(Salen)manganese(V) nitrido species are activated by electrophiles such as trifluoroacetic anhydride (TFAA) or trifluoroacetic acid (TFA) to produce N2. Mechanistic studies suggest that the manganese(V) nitrido species first react with TFAA or TFA to produce an imido species, which then undergoes N...N coupling. It is proposed that the resulting manganese(III) mu-diazene species decomposes via internal redox to give N2 and manganese(II). The manganese(II) species is then rapidly oxidized by manganese(V) imide to give manganese(III) and CF3CONH2 (for TFAA) or NH3 (for TFA).

QSAR analysis for nano-sized layered manganese-calcium oxide in water oxidation: An application of chemometric methods in artificial photosynthesis.

Science.gov (United States)

Shahbazy, Mohammad; Kompany-Zareh, Mohsen; Najafpour, Mohammad Mahdi

2015-11-01

Water oxidation is among the most important reactions in artificial photosynthesis, and nano-sized layered manganese-calcium oxides are efficient catalysts toward this reaction. Herein, a quantitative structure-activity relationship (QSAR) model was constructed to predict the catalytic activities of twenty manganese-calcium oxides toward water oxidation using multiple linear regression (MLR) and genetic algorithm (GA) for multivariate calibration and feature selection, respectively. Although there are eight controlled parameters during synthesizing of the desired catalysts including ripening time, temperature, manganese content, calcium content, potassium content, the ratio of calcium:manganese, the average manganese oxidation state and the surface of catalyst, by using GA only three of them (potassium content, the ratio of calcium:manganese and the average manganese oxidation state) were selected as the most effective parameters on catalytic activities of these compounds. The model's accuracy criteria such as R(2)test and Q(2)test in order to predict catalytic rate for external test set experiments; were equal to 0.941 and 0.906, respectively. Therefore, model reveals acceptable capability to anticipate the catalytic activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Correlation between airborne manganese concentration at the workstations in the iron foundry and manganese concentration in workers’ blood

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Seyedtaghi Mirmohammadi

2017-08-01

Full Text Available Background: Manganese (Mn used as raw material for melting process in the ferrous foundry is considered as hazardous neurotoxic substance because it accumulates in the central nervous system and may cause neurological disorders. The furnace-men and melting department workers are potentially exposed to manganese particles or fume in the workplace. The objective of the research has been to investigate the sources and levels of manganese exposure in the foundry by correlation of blood-manganese (B-Mn and air-manganese (air-Mn measurement. Material and Methods: Air-Mn and Mn of blood serum were measured involving workers who worked in a big-sized foundry during 1 year. The standard method of the Occupational Safety and Health Administration (OSHA ID-121 was used for air and blood assessment and atomic absorption spectroscopy (AAS was carried out for air and blood sample analysis. Results: The air sampling results have revealed that there is a high exposure to manganese (4.5 mg/m3 in the workplace as compared to the National Institute for Occupational Safety and Health’s (NIOSH time weighted average (the reference time-weighted average (TWA = 1 mg/m3. The average blood serum Mn concentration was 2.745 μg/l for subjects working for shorter than 3 months and 274.85 μg/l for subjects working 3–12 months. Conclusions: Against the research hypothesis there was no correlation between the air-Mn concentration and the B-Mn (serum level of manganese in the serum of the exposed subjects. It may be due to short time of air sampling of manganese airborne particles, and a real-time monitoring of airborne manganese particles is suggested for any future study. Med Pr 2017;68(4:449–458

Hydrometallurgical Process and Kinetics of Leaching Manganese from Semi-Oxidized Manganese Ores with Sucrose

Directory of Open Access Journals (Sweden)

Yuhong Wang

2017-02-01

Full Text Available The extraction of manganese from a semi-oxidized manganese ore was investigated with sucrose as the reducing agent in dilute sulfuric acid medium. The kinetics of leaching manganese from the complex ore containing MnCO3 and MnO2 was also investigated. The effects of sucrose and sulfuric acid concentrations, leaching temperature and reaction time on the total Mn (TMn, MnO2 and MnCO3 leaching were investigated. Results showed that MnCO3 could more easily react with hydrogen ions than MnO2 in ores, and MnO2 decomposition could be advantageous for MnCO3 leaching. The leaching efficiencies of 91.8% for total Mn, 91.4% for MnO2 and 96.9% for MnCO3 were obtained under the following optimized conditions: 0.035 mol/L sucrose concentration, 5 mol/L sulfuric acid concentration, 60 min of reaction time and 363.2 K of leaching temperature. In addition, it was found that the leaching process of semi-oxidized manganese ore follows the shrinking core model and the leaching rate was controlled by chemical reaction and diffusion. The apparent activation energy of the total manganese, MnO2, and MnCO3 leaching were 40.83, 40.59, and 53.33 kJ·mol−1, respectively.

Cycle aging studies of lithium nickel manganese cobalt oxide-based batteries using electrochemical impedance spectroscopy

NARCIS (Netherlands)

Maheshwari, Arpit; Heck, Michael; Santarelli, Massimo

2018-01-01

The cycle aging of a commercial 18650 lithium-ion battery with graphite anode and lithium nickel manganese cobalt (NMC) oxide-based cathode at defined operating conditions is studied by regular electrochemical characterization, electrochemical impedance spectroscopy (EIS) and post-mortem analysis.

Soil manganese enrichment from industrial inputs: a gastropod perspective.

Directory of Open Access Journals (Sweden)

Despina-Maria Bordean

Full Text Available Manganese is one of the most abundant metal in natural environments and serves as an essential microelement for all living systems. However, the enrichment of soil with manganese resulting from industrial inputs may threaten terrestrial ecosystems. Several studies have demonstrated harmful effects of manganese exposure by cutaneous contact and/or by soil ingestion to a wide range of soil invertebrates. The link between soil manganese and land snails has never been made although these invertebrates routinely come in contact with the upper soil horizons through cutaneous contact, egg-laying, and feeding activities in soil. Therefore, we have investigated the direct transfer of manganese from soils to snails and assessed its toxicity at background concentrations in the soil. Juvenile Cantareus aspersus snails were caged under semi-field conditions and exposed first, for a period of 30 days, to a series of soil manganese concentrations, and then, for a second period of 30 days, to soils with higher manganese concentrations. Manganese levels were measured in the snail hepatopancreas, foot, and shell. The snail survival and shell growth were used to assess the lethal and sublethal effects of manganese exposure. The transfer of manganese from soil to snails occurred independently of food ingestion, but had no consistent effect on either the snail survival or shell growth. The hepatopancreas was the best biomarker of manganese exposure, whereas the shell did not serve as a long-term sink for this metal. The kinetics of manganese retention in the hepatopancreas of snails previously exposed to manganese-spiked soils was significantly influenced by a new exposure event. The results of this study reveal the importance of land snails for manganese cycling in terrestrial biotopes and suggest that the direct transfer from soils to snails should be considered when precisely assessing the impact of anthropogenic Mn releases on soil ecosystems.

Simple synthetic route to manganese-containing nanowires with the spinel crystal structure

Energy Technology Data Exchange (ETDEWEB)

Yu, Lei; Zhang, Yan; Hudak, Bethany M.; Wallace, Damon K.; Kim, Doo Young; Guiton, Beth S.

2016-08-15

This report describes a new route to synthesize single-crystalline manganese-containing spinel nanowires (NWs) by a two-step hydrothermal and solid-state synthesis. Interestingly, a nanowire or nanorod morphology is maintained during conversion from MnO{sub 2}/MnOOH to CuMn{sub 2}O{sub 4}/Mg{sub 2}MnO{sub 4}, despite the massive structural rearrangement this must involve. Linear sweep voltammetry (LSV) curves of the products give preliminary demonstration that CuMn{sub 2}O{sub 4} NWs are catalytically active towards the oxygen evolution reaction (OER) in alkaline solution, exhibiting five times the magnitude of current density found with pure carbon black. - Highlights: • Synthesis of single-crystalline manganese-containing spinel nanowires. • Binary oxide nanowire converted to ternary oxide wire through solid state reaction. • Approach to structure conversion with shape retention could be generally applicable. • Copper and Manganese display multiple oxidation states with potential for catalysis. • CuMn{sub 2}O{sub 4} nanowires show promise as catalysts for the oxygen evolution reaction.

Manganese in silicon carbide

Energy Technology Data Exchange (ETDEWEB)

Linnarsson, M.K., E-mail: marga@kth.se [Royal Institute of Technology, School of Information and Communication Technology, P.O. Box E229, SE-16440 Kista-Stockhom (Sweden); Hallen, A. [Royal Institute of Technology, School of Information and Communication Technology, P.O. Box E229, SE-16440 Kista-Stockhom (Sweden)

2012-02-15

Structural disorder and relocation of implanted Mn in semi-insulating 4H-SiC has been studied. Subsequent heat treatment of Mn implanted samples has been performed in the temperature range 1400-2000 Degree-Sign C. The depth distribution of manganese is recorded by secondary ion mass spectrometry. Rutherford backscattering spectrometry has been employed for characterization of crystal disorder. Ocular inspection of color changes of heat-treated samples indicates that a large portion of the damage has been annealed. However, Rutherford backscattering shows that after heat treatment, most disorder from the implantation remains. Less disorder is observed in the [0 0 0 1] channel direction compared to [112{sup Macron }3] channel direction. A substantial rearrangement of manganese is observed in the implanted region. No pronounced manganese diffusion deeper into the sample is recorded.

Manganese in silicon carbide

International Nuclear Information System (INIS)

Linnarsson, M.K.; Hallén, A.

2012-01-01

Structural disorder and relocation of implanted Mn in semi-insulating 4H–SiC has been studied. Subsequent heat treatment of Mn implanted samples has been performed in the temperature range 1400–2000 °C. The depth distribution of manganese is recorded by secondary ion mass spectrometry. Rutherford backscattering spectrometry has been employed for characterization of crystal disorder. Ocular inspection of color changes of heat-treated samples indicates that a large portion of the damage has been annealed. However, Rutherford backscattering shows that after heat treatment, most disorder from the implantation remains. Less disorder is observed in the [0 0 0 1] channel direction compared to [112 ¯ 3] channel direction. A substantial rearrangement of manganese is observed in the implanted region. No pronounced manganese diffusion deeper into the sample is recorded.

Reduction of ripening time of full-scale manganese removal filters with manganese oxide-coated media

NARCIS (Netherlands)

Bruins, J.H.; Petrusevski, B.; Slokar, Y.M.; Huysman, K.; Joris, K.; Kruithof, J.C.; Kennedy, M.D.

2015-01-01

Effective manganese removal by conventional aeration-filtration with virgin filter media requires a long ripening time. The aim of this study was to assess the potential of manganese oxide-coated media to shorten the ripening time of filters with virgin media, under practical conditions. A full

Globally sustainable manganese metal production and use.

Science.gov (United States)

Hagelstein, Karen

2009-09-01

The "cradle to grave" concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices-such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also

Microwave Production of Manganese from Manganese (IV) Oxide ...

African Journals Online (AJOL)

Michael O. Mensah

2015-12-02

Dec 2, 2015 ... energy consumption occurs in the upper part of the ferromanganese furnace ... The pre-reduction of manganese ores by carbon has been investigated by Abdel ..... Awaso Bauxite Ore using Waste Pure Water. Sachets as ...

Restoration of growth by manganese in a mutant strain of Escherichia coli lacking most known iron and manganese uptake systems

DEFF Research Database (Denmark)

Taudte, Nadine; German, Nadezhda; Zhu, Yong-Guan

2016-01-01

The interplay of manganese and iron homeostasis and oxidative stress in Escherichia coli can give important insights into survival of bacteria in the phagosome and under differing iron or manganese bioavailabilities. Here, we characterized a mutant strain devoid of all know iron/manganese-uptake ......The interplay of manganese and iron homeostasis and oxidative stress in Escherichia coli can give important insights into survival of bacteria in the phagosome and under differing iron or manganese bioavailabilities. Here, we characterized a mutant strain devoid of all know iron...

Nanostructured manganese oxides as highly active water oxidation catalysts: a boost from manganese precursor chemistry.

Science.gov (United States)

Menezes, Prashanth W; Indra, Arindam; Littlewood, Patrick; Schwarze, Michael; Göbel, Caren; Schomäcker, Reinhard; Driess, Matthias

2014-08-01

We present a facile synthesis of bioinspired manganese oxides for chemical and photocatalytic water oxidation, starting from a reliable and versatile manganese(II) oxalate single-source precursor (SSP) accessible through an inverse micellar molecular approach. Strikingly, thermal decomposition of the latter precursor in various environments (air, nitrogen, and vacuum) led to the three different mineral phases of bixbyite (Mn2 O3 ), hausmannite (Mn3 O4 ), and manganosite (MnO). Initial chemical water oxidation experiments using ceric ammonium nitrate (CAN) gave the maximum catalytic activity for Mn2 O3 and MnO whereas Mn3 O4 had a limited activity. The substantial increase in the catalytic activity of MnO in chemical water oxidation was demonstrated by the fact that a phase transformation occurs at the surface from nanocrystalline MnO into an amorphous MnOx (1manganese oxides including the newly formed amorphous MnOx . Both Mn2 O3 and the amorphous MnOx exhibit tremendous enhancement in oxygen evolution during photocatalysis and are much higher in comparison to so far known bioinspired manganese oxides and calcium-manganese oxides. Also, for the first time, a new approach for the representation of activities of water oxidation catalysts has been proposed by determining the amount of accessible manganese centers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Manganese activated phosphate glass for dosimetry

International Nuclear Information System (INIS)

Regulla, D.

1975-01-01

A measuring element comprises a metaphosphate glass doped with manganese as an activator. The manganese activated metaphosphate glass can detect and determine radiation doses in the range between milliroentgens and more than 10 megaroentgens. (auth)

Determination of semi-empirical relationship between the manganese and hydrogen atoms ratio, physical density and concentration in an aqueous solution of manganese sulphate

Energy Technology Data Exchange (ETDEWEB)

Rodrigues Bittencourt, Guilherme, E-mail: bittencourt@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/n Recreio dos Bandeirantes, CEP 22780-160, Rio de Janeiro, RJ (Brazil); Souza Patrao, Karla Cristina de, E-mail: karla@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/n Recreio dos Bandeirantes, CEP 22780-160, Rio de Janeiro, RJ (Brazil); Passos Leite, Sandro, E-mail: sandro@ird.gov.b [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Wagner Pereira, Walsan, E-mail: walsan@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/n Recreio dos Bandeirantes, CEP 22780-160, Rio de Janeiro, RJ (Brazil); Simoes da Fonseca, Evaldo, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/n Recreio dos Bandeirantes, CEP 22780-160, Rio de Janeiro, RJ (Brazil)

2010-12-15

The Manganese sulphate solution has been used for neutron metrology through the method of Manganese Bath. This method uses physical parameters of manganese sulphate solution to obtain its corrections. This work established a functional relationship, using the gravimetric method, between those physical parameters: density, concentration and hydrogen to manganese ratio. Comparisons were done between manganese sulphate solution concentration from the Manganese Bath system of Laboratory of Metrology of Ionising Radiation and estimated values from the functional relationship obtained, showing percentage difference of less than 0.1%. This result demonstrates the usefulness in the correlation of the physical values of the solution to the MB.

Alternative irradiation system for efficiency manganese bath determination

Energy Technology Data Exchange (ETDEWEB)

Passos Leite, Sandro, E-mail: sandro@ird.gov.b [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Wagner Pereira, Walsan, E-mail: walsan@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/no, Recreio dos Bandeirantes, CEP: 22780-160, Rio de Janeiro (Brazil); Xavier da Silva, Ademir, E-mail: ademir@con.ufrj.b [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Simoes da Fonseca, Evaldo, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/no, Recreio dos Bandeirantes, CEP: 22780-160, Rio de Janeiro (Brazil); Souza Patrao, Karla Cristina de, E-mail: karla@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/no, Recreio dos Bandeirantes, CEP: 22780-160, Rio de Janeiro (Brazil)

2010-12-15

An alternative irradiation system, which works with a radionuclide neutron source and manganese sulphate solution volume have been proposed for efficiency determination of a Manganese Bath System (MBS). This irradiation system was designed by simulation with MCNP5 code, considering a californium neutron source in several manganese sulphate volumes and different neutron reflectors. Although its solution specific activity are less than those in nuclear reactors, the simulation results have showed that the irradiation system proposed takes a manganese neutron capture increase up to 200 times when it compared to manganese neutron capture from a MBS whose diameter is about 100 cm. That becomes possible to use those samples for some of the absolute specific activity measuring methods.

Statistical Optimization of Synthesis of Manganese Carbonates Nanoparticles by Precipitation Methods

International Nuclear Information System (INIS)

Javidan, A.; Rahimi-Nasrabadi, M.; Davoudi, A.A.

2011-01-01

In this study, an orthogonal array design (OAD), OA9, was employed as a statistical experimental method for the controllable, simple and fast synthesis of manganese carbonate nanoparticle. Ultrafine manganese carbonate nanoparticles were synthesized by a precipitation method involving the addition of manganese ion solution to the carbonate reagent. The effects of reaction conditions, for example, manganese and carbonate concentrations, flow rate of reagent addition and temperature, on the diameter of the synthesized manganese carbonate nanoparticle were investigated. The effects of these factors on the width of the manganese carbonate nanoparticle were quantitatively evaluated by the analysis of variance (ANOVA). The results showed that manganese carbonate nanoparticle can be synthesized by controlling the manganese concentration, flow rate and temperature. Finally, the optimum conditions for the synthesis of manganese carbonate nanoparticle by this simple and fast method were proposed. The results of ANOVA showed that 0.001 mol/ L manganese ion and carbonate reagents concentrations, 2.5 mL/ min flow rate for the addition of the manganese reagent to the carbonate solution and 0 degree Celsius temperature are the optimum conditions for producing manganese carbonate nanoparticle with 75 ± 25 nm width. (author)

Magnesium and manganese content of halophilic bacteria

International Nuclear Information System (INIS)

de Medicis, E.; Paquette, J.; Gauthier, J.J.; Shapcott, D.

1986-01-01

Magnesium and manganese contents were measured by atomic absorption spectrophotometry in bacteria of several halophilic levels, in Vibrio costicola, a moderately halophilic eubacterium growing in 1 M NaCl, Halobacterium volcanii, a halophilic archaebacterium growing in 2.5 NaCl, Halobacterium cutirubrum, an extremely halophilic archaebacterium growing in 4 M NaCl, and Escherichia coli, a nonhalophilic eubacterium growing in 0.17 M NaCl. Magnesium and manganese contents varied with the growth phase, being maximal at the early log phase. Magnesium and manganese molalities in cell water were shown to increase with the halophilic character of the logarithmically growing bacteria, from 30 mmol of Mg per kg of cell water and 0.37 mmol of Mn per kg of cell water for E. coli to 102 mmol of Mg per kg of cell water and 1.6 mmol of Mn per kg of cell water for H cutirubrum. The intracellular concentrations of manganese were determined independently by a radioactive tracer technique in V. costicola and H. volcanii. The values obtained by 54 Mn loading represented about 70% of the values obtained by atomic absorption. The increase of magnesium and manganese contents associated with the halophilic character of the bacteria suggests that manganese and magnesium play a role in haloadaptation

Diffusion abnormalities of the globi pallidi in manganese neurotoxicity

Energy Technology Data Exchange (ETDEWEB)

McKinney, Alexander M.; Filice, Ross W.; Teksam, Mehmet; Casey, Sean; Truwit, Charles; Clark, H. Brent; Woon, Carolyn; Liu, Hai Ying [Department of Radiology, Medical School, Box 292, 420 Delaware Street S.E., 55455, Minneapolis, MN (United States)

2004-04-01

Manganese is an essential trace metal required for normal central nervous system function, which is toxic when in excess amounts in serum. Manganese neurotoxicity has been demonstrated in patients with chronic liver/biliary failure where an inability to excrete manganese via the biliary system causes increased serum levels, and in patients on total parenteral nutrition (TPN), occupational/inhalational exposure, or other source of excess exogenous manganese. Manganese has been well described in the literature to deposit selectively in the globi pallidi and to induce focal neurotoxicity. We present a case of a 53-year-old woman who presented for a brain MR 3 weeks after liver transplant due to progressively decreasing level of consciousness. The patient had severe liver failure by liver function tests and bilirubin levels, and had also been receiving TPN since the transplant. The MR demonstrated symmetric hyperintensity on T1-weighted images in the globi pallidi. Apparent diffusion coefficient (ADC) map indicated restricted diffusion in the globi pallidi bilaterally. The patient eventually succumbed to systemic aspergillosis 3 days after the MR. The serum manganese level was 195 mcg/l (micrograms per liter) on postmortem exam (over 20 times the upper limits of normal). The patient was presumed to have suffered from manganese neurotoxicity since elevated serum manganese levels have been shown in the literature to correlate with hyperintensity on T1-weighted images, neurotoxicity symptoms, and focal concentration of manganese in the globi pallidi. Neuropathologic sectioning of the globi pallidi at autopsy was also consistent with manganese neurotoxicity. (orig.)

Metabolism of manganese, iron, copper, and selenium in calves

International Nuclear Information System (INIS)

Ho, S.Y.

1981-01-01

Sixteen male Holstein calves were used to study manganese and iron metabolism. The calves were fed one of the following diets for 18 days: control, control + iron, control + manganese, and control + iron and manganese. All calves were dosed orally with manganese-54. Tissue concentrations of manganese, iron and manganese-54 were determined. Small intestinal iron was lower in calves fed the high manganese diet than in controls. Tissue manganese-54 was lower in calves fed a high manganese diet. Fecal manganese content increased in calves fed both high manganese and high manganese-high iron diets. Serum total iron was not affected by the dietary treatments. To study the effects of high dietary levels of copper and selenium on the intracellular distributions of these two elements in liver and kidney cytosol, calves were fed one of four diets for 15 days. These were 0 and 100 ppM supplemental copper and 0 and 1 ppM added selenium. The control diet containing 0.1 ppM of selenium and 15 ppM of copper. All calves were orally dosed 48 hrs prior to sacrifice with selenium-75. A high copper diet increased copper concentrations in all intracellular liver fractions and most kidney fractions. Only the effects in the liver were significant. Less copper was found in the mitochondria fractions in liver and kidney of calves fed a high selenium diet. Three major copper-binding protein peaks were separated from the soluble fractions of calf liver and kidney. Peak 1 appeared to be the major copper-binding protein in liver and kidney cytosol of copper-loaded animals. Added selenium alone or in combination with copper accentuated the copper accumulation in this peak. Most of selenium-75 was recovered in the same peak as the copper. The results of this experiment indicated that the large molecular proteins in liver and kidney cytosol of calves play an important role in copper and selenium-75 metabolism

Manganese oxide nanoparticles, methods and applications

Science.gov (United States)

Abruna, Hector D.; Gao, Jie; Lowe, Michael A.

2017-08-29

Manganese oxide nanoparticles having a chemical composition that includes Mn.sub.3O.sub.4, a sponge like morphology and a particle size from about 65 to about 95 nanometers may be formed by calcining a manganese hydroxide material at a temperature from about 200 to about 400 degrees centigrade for a time period from about 1 to about 20 hours in an oxygen containing environment. The particular manganese oxide nanoparticles with the foregoing physical features may be used within a battery component, and in particular an anode within a lithium battery to provide enhanced performance.

Efficacies of manganese chloride and Ca-DTPA for the elimination of incorporated manganese-54 in mice

International Nuclear Information System (INIS)

Sato, Itaru; Matsusaka, Naonori; Shinagawa, Kunihiro; Kobayashi, Haruo; Nishimura, Yoshikazu.

1993-01-01

Efficacies of manganese chloride and Ca-DTPA (calcium diethylenetriaminepentaacetic acid) for the elimination of incorporated 54 Mn were investigated in mice. Each mouse was given an intraperitoneal injection of 54 Mn and initial whole-body radioactivity was measured immediately. Manganese chloride (10 mg-Mn/kg) or Ca-DTPA (10 or 100 mg/kg) was injected intraperitoneally once or repeatedly at various times after 54 Mn injection. Efficacies for elimination were estimated by measuring the whole body retention of 54 Mn for 14 or 21 days. A single injection of manganese chloride eliminated more than 80% of the incorporated 54 Mn when it was injected within 24 h after the injection of 54 Mn. Although the efficacy was decreased with the passage of time after the injection of 54 Mn, about 50% was still eliminated after 14 days. Repeated injection of this agent raised the efficacy, but the second or later injection was less effective than the first injection. Ca-DTPA eliminated the incorporated 54 Mn by 57% for 100 mg/kg and by 19% for 10 mg/kg when it was injected after 3 h. But after 6 h or later, Ca-DTPA had little efficacy. These results indicate that manganese chloride is very effective to eliminate the 54 Mn from accidentally contaminated persons and the efficacy of Ca-DTPA is less than that of manganese chloride. (author)

Determination of manganese content in aqueous solutions

International Nuclear Information System (INIS)

Reeder, S.D.; Smith, J.R.

1977-01-01

The three analytical methods used in the hydrogen-to-manganese cross-section ratio measurement were: volumetric determination of manganese, gravimetric analysis of manganous sulfate; and densimetric determination of manganous sulfate

Failure of manganese to protect from Shiga toxin.

Directory of Open Access Journals (Sweden)

Marsha A Gaston

Full Text Available Shiga toxin (Stx, the main virulence factor of Shiga toxin producing Escherichia coli, is a major public health threat, causing hemorrhagic colitis and hemolytic uremic syndrome. Currently, there are no approved therapeutics for these infections; however manganese has been reported to provide protection from the Stx1 variant isolated from Shigella dysenteriae (Stx1-S both in vitro and in vivo. We investigated the efficacy of manganese protection from Stx1-S and the more potent Stx2a isoform, using experimental systems well-established for studying Stx: in vitro responses of Vero monkey kidney cells, and in vivo toxicity to CD-1 outbred mice. Manganese treatment at the reported therapeutic concentration was toxic to Vero cells in culture and to CD-1 mice. At lower manganese concentrations that were better tolerated, we observed no protection from Stx1-S or Stx2a toxicity. The ability of manganese to prevent the effects of Stx may be particular to certain cell lines, mouse strains, or may only be manifested at high, potentially toxic manganese concentrations.

Manganese Research Health Project (MHRP)

Science.gov (United States)

2009-02-01

green nucleic acid staining further confirmed the neurotoxic effect of cadmium in this cell model (Fig 10C). Next, we examined the enzymatic activity...Quantification of Nissl bodies revealed a widespread reduction in SNpc cell numbers. Other areas of the basal ganglia were also altered by manganese as...the substantia nigra pars compacta (SNpc) following manganese treatment. Quantification of Nissl bodies revealed a widespread reduction in SNpc

Characterization of a manganese ore to define the use in the fluxes synthesis for submerged arc welding

International Nuclear Information System (INIS)

Cruz, A.; Quintana, R.; Perdomo, L.; Garcia, L. L.; Formoso, A.; Cores, A.

2003-01-01

Chemical analysis, thermal analysis (DTA and TG), phase determination by X-ray diffraction and granulometric analysis of the manganese ore from the location Margarita de Cambute in the eastern part of cuba were carried out. Based on these characterization results, a flux synthesis strategy was established, comprising the definition, as a basic condition, of the MnO/SiO 2 range of values. This strategy was confirmed experimentally by obtaining a flux prototype in an electric arc furnace connected to direct current source and the carrying out of the flux in submerged arc welding tests. (Author) 26 refs

Thermodynamic Properties of Manganese and Molybdenum

International Nuclear Information System (INIS)

Desai, P.D.

1987-01-01

This work reviews and discusses the data on the various thermodynamic properties of manganese and molybdenum available through March 1985. These include heat capacity, enthalpy, enthalpy of transitions and melting, vapor pressure, and enthalpy of vaporization. The existing data have been critically evaluated and analyzed. The recommended values for the heat capacity, enthalpy, entropy, and Gibbs energy function from 0.5 to 2400 K for manganese and from 0.4 to 5000 K for molybdenum have been generated, as have heat capacity values for supercooled β-Mn and for γ-Mn below 298.15 K. The recommended values for vapor pressure cover the temperature range from 298.15 to 2400 K for manganese and from 298.15 to 5000 K for molybdenum. These values are referred to temperatures based on IPTS-1968. The uncertainties in the recommended values of the heat capacity range from +-3% to +-5% for manganese and from +-1.5% to +-3% for molybdenum

THE STATE OF MANGANESE IN THE PHOTOSYNTHETIC APPARATUS. I. EXAFS STUDIES ON CHLOROPLASTS AND di-u-oxo BRIDGED di-MANGANESE MODEL COMPOUNDS

Energy Technology Data Exchange (ETDEWEB)

Kirby, J. A.; Robertson, A. S.; Smith, J. P.; Thompson, A. C.; Thompson, A. C.; Klein, M. P.

1980-11-01

Extended X-ray Absorption Fine Structure (EXAFS) studies on the manganese contained in spinach chloroplasts and on certain di-u-oxo bridged manganese dimers of the form (X{sub 2}Mn)O{sub 2}(MnX{sub 2} (X=2,2'-bypyridine and 1,10-phenanthroline) are reported. From these studies, the manganese associated with photosynthetic oxygen evolution is suggested to occur as a bridged transition metal dimer with most likely another manganese. Extensive details on the analysis are included.

Manganese exposure in foundry furnacemen and scrap recycling workers

DEFF Research Database (Denmark)

Lander, F; Kristiansen, J; Lauritsen, Jens

1999-01-01

Cast iron products are alloyed with small quantities of manganese, and foundry furnacemen are potentially exposed to manganese during tapping and handling of smelts. Manganese is a neurotoxic substance that accumulates in the central nervous system, where it may cause a neurological disorder...

Status and Role of Manganese in the Environment

Directory of Open Access Journals (Sweden)

RK Kamble

2014-09-01

Full Text Available Manganese is the second most abundant heavy metal, and in frequency list of elements it occupies 12th place. The Earth’s core contains about 1.5% manganese. According to Indian Standards for Drinking water (IS 10500:2012 manganese concentration in drinking water is 0.1 ppm (acceptable limit and 0.3 ppm as permissible limit. An attempt has been made to record the presence of manganese in different environmental matrices such as air, water, soil, food, its effects on plants, animals including human beings. DOI: http://dx.doi.org/10.3126/ije.v3i3.11081 International Journal of Environment Vol.3(3 2014: 222-234

Manganese and acute paranoid psychosis: a case report

Directory of Open Access Journals (Sweden)

Egger Jos I

2011-04-01

Full Text Available Abstract Introduction Manganese regulates many enzymes and is essential for normal development and body function. Chronic manganese intoxication has an insidious and progressive course and usually starts with complaints of headache, fatigue, sleep disturbances, irritability and emotional instability. Later, several organ systems may be affected and, due to neurotoxicity, an atypical parkinsonian syndrome may emerge. With regard to neuropsychiatry, an array of symptoms may develop up to 30 years after intoxication, of which gait and speech abnormalities, cognitive and motor slowing, mood changes and hallucinations are the most common. Psychotic phenomena are rarely reported. Case presentation We describe the case of a 49-year-old Caucasian man working as a welder who was referred to our facility for evaluation of acute paranoid psychotic behavior. Our patient's medical history made no mention of any somatic complaints or psychiatric symptoms, and he had been involved in a professional career as a metalworker. On magnetic resonance imaging scanning of his brain, a bilateral hyperdensity of the globus pallidus, suggestive for manganese intoxication, was found. His manganese serum level was 52 to 97 nmol/L (range: 7 to 20 nmol/L. A diagnosis of organic psychotic disorder due to manganese overexposure was made. His psychotic symptoms disappeared within two weeks of treatment with low-dose risperidone. At three months later, serum manganese was decreased to slightly elevated levels and the magnetic resonance imaging T1 signal intensity was reduced. No signs of Parkinsonism were found and a definite diagnosis of manganese-induced apathy syndrome was made. Conclusion Although neuropsychiatric and neurological symptoms caused by (chronic manganese exposure have been reported frequently in the past, in the present day the disorder is rarely diagnosed. In this report we stress that manganese intoxication can still occur, in our case in a confined

Manganese contents of soils as determined by activation analysis

International Nuclear Information System (INIS)

El-Kholi, A.F.; Hamdy, A.A.; Al Metwally, A.I.; El-Damaty, A.H.

1976-01-01

The object of this investigation is to determine total manganese by means of neutron activation analysis and evaluate this technique in comparison with the corresponding data obtained by conventional chemical analysis. Data obtained revealed that the values of total manganese in calcareous soils obtained by both chemical analysis and that by neutron activation analysis were similar. Therefore, activation analysis could be recommended as a quick laboratory, less tedious, and time consuming method for the determination of Mn content in both soils and plants than the conventional chemical techniques due to its great specificity, sensitivity and simplicity. Statistical analysis showed that there is a significant correlation at 5% probability level between manganese content in Soybean plant and total manganese determined by activation and chemical analysis giving the evidence that in the case of those highly calcareous soils of low total manganese content this fraction has to be considered as far as available soil manganese is concerned

Manganese oxide-based materials as electrochemical supercapacitor electrodes.

Science.gov (United States)

Wei, Weifeng; Cui, Xinwei; Chen, Weixing; Ivey, Douglas G

2011-03-01

Electrochemical supercapacitors (ECs), characteristic of high power and reasonably high energy densities, have become a versatile solution to various emerging energy applications. This critical review describes some materials science aspects on manganese oxide-based materials for these applications, primarily including the strategic design and fabrication of these electrode materials. Nanostructurization, chemical modification and incorporation with high surface area, conductive nanoarchitectures are the three major strategies in the development of high-performance manganese oxide-based electrodes for EC applications. Numerous works reviewed herein have shown enhanced electrochemical performance in the manganese oxide-based electrode materials. However, many fundamental questions remain unanswered, particularly with respect to characterization and understanding of electron transfer and atomic transport of the electrochemical interface processes within the manganese oxide-based electrodes. In order to fully exploit the potential of manganese oxide-based electrode materials, an unambiguous appreciation of these basic questions and optimization of synthesis parameters and material properties are critical for the further development of EC devices (233 references).

Effects of dietary manganese contents on 54Mn metabolism in mice

International Nuclear Information System (INIS)

Sato, I.; Matsusaka, N.; Kobayashi, H.; Nishimura, Y.

1996-01-01

Several parameters of 54 Mn metabolism were noted in mice maintained on diets with manganese contents of 80 to 8000 mg/kg. Excretion of 54 Mn was promoted as the dietary manganese contents increased. Clearance of 54 Mn from the liver, kidneys, pancreas, and spleen was markedly accelerated by feeding mice a high-manganese diet, but clearance from the muscles, femurs, and brain was relatively insensitive to the dietary manganese. Manganese concentrations in the tissue were regulated homoestatically upto the dietary manganese content of 2400 mg/kg, but marked accumulations of manganese occurred when mice were given 8000 mg/kg diet. No toxic symptoms were found up to the 2400 mg/kg diet, but consumption of the 8000 mg/kg diet was less than for other diets. These results suggest that an oral intake of excess manganese is effective for promoting the excretion of 54 Mn from a body contaminated with this isotope. (author)

Welding fumes from stainless steel gas metal arc processes contain multiple manganese chemical species.

Science.gov (United States)

Keane, Michael; Stone, Samuel; Chen, Bean

2010-05-01

Fumes from a group of gas metal arc welding (GMAW) processes used on stainless steel were generated using three different metal transfer modes and four different shield gases. The objective was to identify and measure manganese (Mn) species in the fumes, and identify processes that are minimal generators of Mn species. The robotic welding system was operated in short-circuit (SC) mode (Ar/CO2 and He/Ar), axial spray (AXS) mode (Ar/O2 and Ar/CO2), and pulsed axial-spray (PAXS) mode (Ar/O2). The fumes were analyzed for Mn by a sequential extraction process followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, and by X-ray diffraction (XRD). Total elemental Mn, iron (Fe), chromium (Cr) and nickel (Ni) were separately measured after aqua regia digestion and ICP-AES analysis. Soluble Mn2+, Fe2+, Fe3+, and Ni2+ in a simple biological buffer (phosphate-buffered saline) were determined at pH 7.2 and 5.0 after 2 h incubation at 37 C by ion chromatography. Results indicate that Mn was present in soluble form, acid-soluble form, and acid-soluble form after reduction by hydroxylamine, which represents soluble Mn0 and Mn2+ compounds, other Mn2+ compounds, and (Mn3+ and Mn4+) compounds, respectively. The dominant fraction was the acid-soluble Mn2+ fraction, but results varied with the process and shield gas. Soluble Mn mass percent in the fume ranged from 0.2 to 0.9%, acid-soluble Mn2+ compounds ranged from 2.6 to 9.3%, and acid plus reducing agent-soluble (Mn3+ and Mn4+) compounds ranged from 0.6 to 5.1%. Total Mn composition ranged from 7 to 15%. XRD results showed fumes had a crystalline content of 90-99% Fe3O4, and showed evidence of multiple Mn oxides, but overlaps and weak signals limited identification. Small amounts of the Mn2+ in the fume (welding process. Mn generation rates for the fractions were tabulated, and the influence of ozone is discussed. The conclusions are that exposures to welding fumes include multiple Mn species, both

Permanganate-based synthesis of manganese oxide nanoparticles in ferritin

Science.gov (United States)

Olsen, Cameron R.; Smith, Trevor J.; Embley, Jacob S.; Maxfield, Jake H.; Hansen, Kameron R.; Peterson, J. Ryan; Henrichsen, Andrew M.; Erickson, Stephen D.; Buck, David C.; Colton, John S.; Watt, Richard K.

2017-05-01

This paper investigates the comproportionation reaction of MnII with {{{{MnO}}}4}- as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that {{{{MnO}}}4}- serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin.

Mercury distribution characteristics in primary manganese smelting plants

International Nuclear Information System (INIS)

Back, Seung-Ki; Sung, Jin-Ho; Moon, Young-Hoon; Kim, Young-Hee; Seok, Kwang-Seol; Song, Geum-Ju; Seo, Yong-Chil

2017-01-01

The mercury (Hg) distribution characteristics were investigated in three primary manganese smelting plants in Korea for the assessment of anthropogenic Hg released. Input and output materials were sampled from each process, and Hg concentrations in the samples were analyzed. Among the input materials, the most mercury was found in the manganese ore (83.1–99.7%) and mercury was mainly released through fly ash or off gas, depending on the condition of off gas cleaning system. As off gas temperature decreases, proportion and concentration of emitted gaseous elemental mercury (Hg 0 ) in off gas decreases. Based on mass balance study from these three plants and national manganese production data, the total amount of mercury released from those Korean plants was estimated to 644 kg/yr. About half of it was emitted into the air while the rest was released to waste as fly ash. With the results of this investigation, national inventory for Hg emission and release could be updated for the response to Minamata Convention on Mercury. - Graphical abstract: 1. Lack of data on mercury (Hg) distribution in manganese smelters. 2. Mass distribution of Hg released from 3 plants (as normalized values) were made as follows by measurements. 3. Information of distribution of Hg in Manganese smelters would be used for emission in to air and releases to other streams for the nation and globe in UNEP mercury report. - Highlights: • The mass balance study by on-site measurement from primary manganese smelting plants was made at first time in the world. • Hg distribution and main input and release pathways of Hg from primary manganese smelting plants could be found as the first time. • Gas temperature in bag filter affects Hg behavior and speciation changes in APCDs. • National inventory of Hg emssion has been updated with new data. - Mercury distribution in manganese smelting plant was investigated as the first measurements at commercial plants in the world. National Hg release

Alternative method of portable irradiation of manganese sulphate solution by an plutonium-beryllium source for manganese sulphate bath efficiency measurements; Metodo alternativo de irradiacao portatil da solucao de sulfato de manganes por uma fonte de plutonio-berilio para medicoes de eficiencia do banho de sulfato de manganes

Energy Technology Data Exchange (ETDEWEB)

Silva, Fellipe Souza da; Martins, Marcelo Marques; Pereira, Walsan Wagner, E-mail: fellipess@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2016-07-01

This study intends to create an alternative irradiation system from a Plutonium-Beryllium source for manganese sulphate solution using the Monte Carlo code. Thus seeking to eliminate the issue of institutes that do not have reactors or particle accelerators in its infrastructure, in order to optimize and provide independence for them to carry out efficiency measurements of MnSO{sub 4} solution in their own locality. The Monte Carlo simulations defined the technical features of this new system so that the solution reaches the maximum neutron capture by manganese in solution. (author)

Transcriptome Analysis of Manganese-deficient Chlamydomonas reinhardtii Provides Insight on the Chlorophyll Biosynthesis Pathway

Energy Technology Data Exchange (ETDEWEB)

Lockhart, Ainsley; Zvenigorodsky, Natasha; Pedraza, Mary Ann; Lindquist, Erika

2011-08-11

The biosynthesis of chlorophyll and other tetrapyrroles is a vital but poorly understood process. Recent genomic advances with the unicellular green algae Chlamydomonas reinhardtii have created opportunity to more closely examine the mechanisms of the chlorophyll biosynthesis pathway via transcriptome analysis. Manganese is a nutrient of interest for complex reactions because of its multiple stable oxidation states and role in molecular oxygen coordination. C. reinhardtii was cultured in Manganese-deplete Tris-acetate-phosphate (TAP) media for 24 hours and used to create cDNA libraries for sequencing using Illumina TruSeq technology. Transcriptome analysis provided intriguing insight on possible regulatory mechanisms in the pathway. Evidence supports similarities of GTR (Glutamyl-tRNA synthase) to its Chlorella vulgaris homolog in terms of Mn requirements. Data was also suggestive of Mn-related compensatory up-regulation for pathway proteins CHLH1 (Manganese Chelatase), GUN4 (Magnesium chelatase activating protein), and POR1 (Light-dependent protochlorophyllide reductase). Intriguingly, data suggests possible reciprocal expression of oxygen dependent CPX1 (coproporphyrinogen III oxidase) and oxygen independent CPX2. Further analysis using RT-PCR could provide compelling evidence for several novel regulatory mechanisms in the chlorophyll biosynthesis pathway.

Manganese Catalyzed C–H Halogenation

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei; Groves, John T.

2015-06-16

The remarkable aliphatic C–H hydroxylations catalyzed by the heme-containing enzyme, cytochrome P450, have attracted sustained attention for more than four decades. The effectiveness of P450 enzymes as highly selective biocatalysts for a wide range of oxygenation reactions of complex substrates has driven chemists to develop synthetic metalloporphyrin model compounds that mimic P450 reactivity. Among various known metalloporphyrins, manganese derivatives have received considerable attention since they have been shown to be versatile and powerful mediators for alkane hydroxylation and olefin epoxidation. Mechanistic studies have shown that the key intermediates of the manganese porphyrin-catalyzed oxygenation reactions include oxo- and dioxomanganese(V) species that transfer an oxygen atom to the substrate through a hydrogen abstraction/oxygen recombination pathway known as the oxygen rebound mechanism. Application of manganese porphyrins has been largely restricted to catalysis of oxygenation reactions until recently, however, due to ultrafast oxygen transfer rates. In this Account, we discuss recently developed carbon–halogen bond formation, including fluorination reactions catalyzed by manganese porphyrins and related salen species. We found that biphasic sodium hypochlorite/manganese porphyrin systems can efficiently and selectively convert even unactivated aliphatic C–H bonds to C–Cl bonds. An understanding of this novel reactivity derived from results obtained for the oxidation of the mechanistically diagnostic substrate and radical clock, norcarane. Significantly, the oxygen rebound rate in Mn-mediated hydroxylation is highly correlated with the nature of the trans-axial ligands bound to the manganese center (L–Mn^V$=$O). Based on the ability of fluoride ion to decelerate the oxygen rebound step, we envisaged that a relatively long-lived substrate radical could be trapped by a Mn–F fluorine source, effecting carbon–fluorine bond

Occupational neurotoxicology due to heavy metals-especially manganese poisoning

International Nuclear Information System (INIS)

Inoue, Naohide

2007-01-01

The most hazardous manganese exposures occur in mining and smelting of ore. Recently, the poisoning has been frequently reported to be associated with welding. In occupational exposure, manganese is absorbed mainly by inhalation. Manganese preferentially accumulates in tissues rich in mitochondria. It also penetrates the blood brain barrior and accumulate in the basal ganglia, especially the globus pallidus, but also the striatum. Manganese poisoning is clinically characterized by the central nervous system involvement including psychiatric symptomes, extrapyramidal signs, and less frequently other neurological manifestations. Psychiatric symptomes are well described in the manganese miners and incrude sleep disturbance, disorientation, emotional lability, compulsive acts, hallucinations, illusions, and delusions. The main characteristic manifestations usually begin shortly after the appearance of these psychiatric symptomes. The latter neurological signs are progressive bradykinesia, dystonia, and disturbance of gait. Bradykinesia is one of the most important findings. There is a remarkable slowing of both active and passive movements of the extremities. Micrographia is frequently observed and a characteristic finding. The patients may show some symmetrical tremor, which usually not so marked. The dystonic posture of the limbs is often accompanied by painfull cramps. This attitudal hypertonia has a tendency to decrease or disappear in the supine position and to increase in orthostation. Cog-wheel rigidity is also elisited on the passive movement of all extremities. Gait disturbance is also characteristic in this poisoning. In the severe cases, cook gait has been reported. The patient uses small steps, but has a tendency to elevate the heels and to rotate them outward. He progress without pressing on the flat of his feet, but only upon the metatarsophalangeal articulations, mainly of the fourth and fifth toes. Increased signal in T1-weighted image in the basal

A magnetic route to measure the average oxidation state of mixed-valent manganese in manganese oxide octahedral molecular sieves (OMS).

Science.gov (United States)

Shen, Xiong-Fei; Ding, Yun-Shuang; Liu, Jia; Han, Zhao-Hui; Budnick, Joseph I; Hines, William A; Suib, Steven L

2005-05-04

A magnetic route has been applied for measurement of the average oxidation state (AOS) of mixed-valent manganese in manganese oxide octahedral molecular sieves (OMS). The method gives AOS measurement results in good agreement with titration methods. A maximum analysis deviation error of +/-7% is obtained from 10 sample measurements. The magnetic method is able to (1) confirm the presence of mixed-valent manganese and (2) evaluate AOS and the spin states of d electrons of both single oxidation state and mixed-valent state Mn in manganese oxides. In addition, the magnetic method may be extended to (1) determine AOS of Mn in manganese oxide OMS with dopant "diamagnetic" ions, such as reducible V5+ (3d0) ions, which is inappropriate for the titration method due to interference of redox reactions between these dopant ions and titration reagents, such as KMnO4, (2) evaluate the dopant "paramagnetic" ions that are present as clusters or in the OMS framework, and (3) determine AOS of other mixed-valent/single oxidation state ion systems, such as Mo3+(3d3)-Mo4+(3d2) systems and Fe3+ in FeCl3.

Energy-Aware Routing in Multiple Domains Software-Defined Networks

Directory of Open Access Journals (Sweden)

Adriana FERNÁNDEZ-FERNÁNDEZ

2016-12-01

Full Text Available The growing energy consumption of communication networks has attracted the attention of the networking researchers in the last decade. In this context, the new architecture of Software-Defined Networks (SDN allows a flexible programmability, suitable for the power-consumption optimization problem. In this paper we address the issue of designing a novel distributed routing algorithm that optimizes the power consumption in large scale SDN with multiple domains. The solution proposed, called DEAR (Distributed Energy-Aware Routing, tackles the problem of minimizing the number of links that can be used to satisfy a given data traffic demand under performance constraints such as control traffic delay and link utilization. To this end, we present a complete formulation of the optimization problem that considers routing requirements for control and data plane communications. Simulation results confirm that the proposed solution enables the achievement of significant energy savings.

Modeling Manganese Sorption and Surface Oxidation During Filtration

OpenAIRE

Bierlein, Kevin Andrew

2012-01-01

Soluble manganese (Mn) is a common contaminant in drinking water sources. High levels of Mn can lead to aesthetic water quality problems, necessitating removal of Mn during treatment to minimize consumer complaints. Mn may be removed during granular media filtration by the â natural greensand effect,â in which soluble Mn adsorbs to manganese oxide-coated (MnOx(s)) media and is then oxidized by chlorine, forming more manganese oxide. This research builds on a previous model developed by Mer...

Aquatic environmental risk assessment of manganese processing industries.

Science.gov (United States)

Marks, Becky; Peters, Adam; McGough, Doreen

2017-01-01

An environmental risk assessment (ERA) has been conducted for sites producing and processing manganese and its inorganic compounds, focussing on potential risks to freshwater. A site specific questionnaire was used to collect information. Sites fall into three broad categories: mining sites, refining sites, and sites producing chemicals and pigments. Waste disposal is principally carried out by the treatment of liquid wastes to separate solids for disposal off-site with a consented wastewater discharge, or disposal on-site using evaporation or settlement ponds in order to maintain the waste materials in a suitable manner following site closure. The main source of emissions from refining and alloying sites is from the treatment of emissions to air using wet scrubber air filters. There is also the potential for fugitive environmental emissions of manganese from stockpiles of raw material held on-site. Data provided from the questionnaires were both site-specific and also commercially sensitive. Therefore, this paper has undertaken the manganese exposure assessment, using a probabilistic approach to reflect the distribution of emissions of manganese and also to maintain the confidentiality of site specific data. An inverse correlation was observed between the total annual tonnage of manganese processed at the site and the emission factor, such that sites processing larger quantities resulted in lower emissions of manganese per tonne processed. The hazard assessment determined a Predicted No Effect Concentration (PNEC) for freshwater using a species sensitivity distribution approach, resulting in a freshwater PNEC of 0.075mgL -1 for soluble manganese. Based on the exposure data and the freshwater PNEC derived for this study, the distributions of risk characterisation ratios using the probabilistic approach indicates that two thirds of manganese processing sites would not be expected to pose a potential risk to the local aquatic environment due to wastewater emissions

Removal of Iron and Manganese in Groundwater using Natural Biosorbent

Science.gov (United States)

Baharudin, F.; Tadza, M. Y. Mohd; Imran, S. N. Mohd; Jani, J.

2018-04-01

This study was conducted to measure and compare the concentration of iron, manganese and hardness of the river and groundwater and to determine the effectiveness of iron and manganese removal by using natural biosorbent which is banana peels. The samples of river and groundwater were collected at riverbank filtration site at Jenderam Hilir, Dengkil. Based on the water quality investigation, the concentration of iron and manganese in the samples of groundwater have exceeded the drinking water quality standard which are 0.3 mg/L for iron and 0.1 mg/L for manganese. The removal process of the iron and manganese in the groundwater was done by using 2, 4 and 8 grams of banana peels activated carbon. It is found that with higher amount of activated banana peels, the removal of iron and manganese is more effective. The ranges of percentage of iron and manganese removal are between 82.25% to 90.84% and 98.79% to 99.43% respectively. From the result, banana peels activated carbon can be concluded as a one of the most effective low-cost adsorbent for groundwater treatment.

Photogeochemical reactions of manganese under anoxic conditions

Science.gov (United States)

Liu, W.; Yee, N.; Piotrowiak, P.; Falkowski, P. G.

2017-12-01

Photogeochemistry describes reactions involving light and naturally occurring chemical species. These reactions often involve a photo-induced electron transfer that does not occur in the absence of light. Although photogeochemical reactions have been known for decades, they are often ignored in geochemical models. In particular, reactions caused by UV radiation during an ozone free early Earth could have influenced the available oxidation states of manganese. Manganese is one of the most abundant transition metals in the crust and is important in both biology and geology. For example, the presence of manganese (VI) oxides in the geologic record has been used as a proxy for oxygenic photosynthesis; however, we suggest that the high oxidation state of Mn can be produced abiotically by photochemical reactions. Aqueous solutions of manganese (II) as well as suspensions of rhodochrosite (MnCO3) were irradiated under anoxic condition using a 450 W mercury lamp and custom built quartz reaction vessels. The photoreaction of the homogeneous solution of Mn(II) produced H2 gas and akhtenskite (ɛ-MnO2) as the solid product . This product is different than the previously identified birnessite. The irradiation of rhodochrosite suspensions also produced H2 gas and resulted in both a spectral shift as well as morphology changes of the mineral particles in the SEM images. These reactions offer alternative, abiotic pathways for the formation of manganese oxides.

Removal of Arsenic, Iron, Manganese, and Ammonia in Drinking Water: Nagaoka International Corporation CHEMILES NCL Series Water Treatment System

Science.gov (United States)

The Nagaoka International Corporation CHEMILES NCL Series system was tested to verify its performance for the reduction of multiple contaminants including: arsenic, ammonia, iron, and manganese. The objectives of this verification, as operated under the conditions at the test si...

Manganese and acute paranoid psychosis: A case report

NARCIS (Netherlands)

W.M.A. Verhoeven (Wim); J.I.M. Egger (Jos); H.J. Kuijpers (Harold)

2011-01-01

textabstractIntroduction: Manganese regulates many enzymes and is essential for normal development and body function. Chronic manganese intoxication has an insidious and progressive course and usually starts with complaints of headache, fatigue, sleep disturbances, irritability and emotional

Defining active progressive multiple sclerosis

DEFF Research Database (Denmark)

Sellebjerg, Finn; Börnsen, Lars; Ammitzbøll, Cecilie

2017-01-01

BACKGROUND: It is unknown whether disease activity according to consensus criteria (magnetic resonance imaging activity or clinical relapses) associate with cerebrospinal fluid (CSF) changes in progressive multiple sclerosis (MS). OBJECTIVE: To compare CSF biomarkers in active and inactive...

Preparation and performance of manganese-oxide-coated zeolite for the removal of manganese-contamination in groundwater.

Science.gov (United States)

Lyu, Cong; Yang, Xuejiao; Zhang, Shengyu; Zhang, Qihui; Su, Xiaosi

2017-12-29

A promising and easily prepared catalytic filler media, manganese-oxide-coated zeolite (MOCZ), for the removal of Mn (II) contamination in groundwater was studied. The optimal condition for MOCZ preparation was given as follows: acid activation of zeolite with 5% HCl mass percent for 12 h, then soaking of acid-activated zeolite with 7% KMnO 4 mass percent for 8 h, and finally calcination at 300°C for 5 h. Acid activation significantly enlarged the specific surface area of the zeolite (>79 m 2  g -1 ), subsequently enhancing the coating of manganese oxides onto the surface of the zeolite. This was further supported by the manganese-to-zeolite ratio (γ Mn ) and Energy dispersive analysis-mapping. The γ Mn was over 12.26 mg Mn g -1 zeolite, representing more active sites for the adsorption and catalytic-oxidation of Mn (II). As such, great performance of Mn (II) removal by MOCZ was obtained in the filter experiment. An estimated 98-100% removal efficiency of Mn (II) was achieved in a greatly short startup time (only 2 h). During the filtration process, newborn flocculent manganese oxides with a mixed-valence of manganese (Mn (II) and Mn (IV)) were generated on the MOCZ surface, further facilitating the adsorption and catalytic-oxidation of Mn (II). The filter with MOCZ as adsorbent had a great performance on the Mn (II) removal in a wide range of hydraulic retention time (HRT) (4-40 min), particularly in a short HRT. Besides, the filter prolonged the filtration period (60 days), which would significantly reduce the frequency of backwash. Thus, it could be concluded that MOCZ prepared in this study showed a good performance in terms of Mn (II) removal in waterworks, especially small waterworks in the villages/towns.

Manganese and acute paranoid psychosis: a case report

NARCIS (Netherlands)

Verhoeven, W.M.A.; Egger, J.I.M.; Kuijpers, H.J.H.

2011-01-01

Introduction Manganese regulates many enzymes and is essential for normal development and body function. Chronic manganese intoxication has an insidious and progressive course and usually starts with complaints of headache, fatigue, sleep disturbances, irritability and emotional instability. Later,

Simultaneous stripping recovery of ammonia-nitrogen and precipitation of manganese from electrolytic manganese residue by air under calcium oxide assist.

Science.gov (United States)

Chen, Hongliang; Liu, Renlong; Shu, Jiancheng; Li, Wensheng

2015-01-01

Leaching tests of electrolytic manganese residue (EMR) indicated that high contents of soluble manganese and ammonia-nitrogen posed a high environmental risk. This work reports the results of simultaneous stripping recovery of ammonia-nitrogen and precipitation of manganese by air under calcium oxide assist. The ammonia-nitrogen stripping rate increased with the dosage of CaO, the air flow rate and the temperature of EMR slurry. Stripped ammonia-nitrogen was absorbed by a solution of sulfuric acid and formed soluble (NH4)2SO4 and (NH4)3H(SO4)3. The major parameters that effected soluble manganese precipitation were the dosage of added CaO and the slurry temperature. Considering these two aspects, the efficient operation conditions should be conducted with 8 wt.% added CaO, 60°C, 800 mL min(-1) air flow rate and 60-min reaction time. Under these conditions 99.99% of the soluble manganese was precipitated as Mn3O4, which was confirmed by XRD and SEM-EDS analyses. In addition, the stripping rate of ammonia-nitrogen was 99.73%. Leaching tests showed the leached toxic substances concentrations of the treated EMR met the integrated wastewater discharge standard of China (GB8978-1996).

Nanostructured manganese oxide thin films as electrode material for supercapacitors

Science.gov (United States)

Xia, Hui; Lai, Man On; Lu, Li

2011-01-01

Electrochemical capacitors, also called supercapacitors, are alternative energy storage devices, particularly for applications requiring high power densities. Recently, manganese oxides have been extensively evaluated as electrode materials for supercapacitors due to their low cost, environmental benignity, and promising supercapacitive performance. In order to maximize the utilization of manganese oxides as the electrode material for the supercapacitors and improve their supercapacitive performance, the nanostructured manganese oxides have therefore been developed. This paper reviews the synthesis of the nanostructured manganese oxide thin films by different methods and the supercapacitive performance of different nanostructures.

Spatial and temporal variations of manganese concentrations in drinking water.

Science.gov (United States)

Barbeau, Benoit; Carrière, Annie; Bouchard, Maryse F

2011-01-01

The objective of this study was to assess the variability of manganese concentrations in drinking water (daily, seasonal, spatial) for eight communities who participated in an epidemiological study on neurotoxic effects associated with exposure to manganese in drinking water. We also assessed the performance of residential point-of-use and point-of-entry devices (POE) for reducing manganese concentrations in water. While the total Mn concentrations measured during this study were highly variable depending on the location (manganese concentration for 4 out of 5 sampling locations. The efficiency of reverse osmosis and ion exchange for total Mn removal was consistently high while activated carbon provided variable results. The four POE greensand filters investigated all increased (29 to 199%) manganese concentration, indicating deficient operation and/or maintenance practices. Manganese concentrations in the distribution system were equal or lower than at the inlet, indicating that sampling at the inlet of the distribution system is conservative. The decline in total Mn concentration was linked to higher water residence time in the distribution system.

Silver manganese oxide electrodes for lithium batteries

Science.gov (United States)

Thackeray, Michael M.; Vaughey, John T.; Dees, Dennis W.

2006-05-09

This invention relates to electrodes for non-aqueous lithium cells and batteries with silver manganese oxide positive electrodes, denoted AgxMnOy, in which x and y are such that the manganese ions in the charged or partially charged electrodes cells have an average oxidation state greater than 3.5. The silver manganese oxide electrodes optionally contain silver powder and/or silver foil to assist in current collection at the electrodes and to improve the power capability of the cells or batteries. The invention relates also to a method for preparing AgxMnOy electrodes by decomposition of a permanganate salt, such as AgMnO4, or by the decomposition of KMnO4 or LiMnO4 in the presence of a silver salt.

Multiple cues add up in defining a figure on a ground.

Science.gov (United States)

Devinck, Frédéric; Spillmann, Lothar

2013-01-25

We studied the contribution of multiple cues to figure-ground segregation. Convexity, symmetry, and top-down polarity (henceforth called wide base) were used as cues. Single-cue displays as well as ambiguous stimulus patterns containing two or three cues were presented. Error rate (defined by responses to uncued stimuli) and reaction time were used to quantify the figural strength of a given cue. In the first experiment, observers were asked to report which of two regions, left or right, appeared as foreground figure. Error rate did not benefit from adding additional cues if convexity was present, suggesting that responses were based on convexity as the predominant figural determinant. However, reaction time became shorter with additional cues even if convexity was present. For example, when symmetry and wide base were added, figure-ground segregation was facilitated. In a second experiment, stimulus patterns were exposed for 150ms to rule out eye movements. Results were similar to those found in the first experiment. Both experiments suggest that under the conditions of our experiment figure-ground segregation is perceived more readily, when several cues cooperate in defining the figure. Copyright © 2012 Elsevier Ltd. All rights reserved.

Bioconcentration of manganese and iron in Panaeoloideae Sing

NARCIS (Netherlands)

Stijve, T.; Blake, C.

1994-01-01

According to literature, the manganese content of most basidiomycetes fluctuates between 10 and 60 mg/kg, whereas the iron levels range from 100-500 mg/kg (both expressed on dry weight). The present authors report that bioconcentration of manganese is a distinguishing feature of the Panaeoloideae,

Spatial mapping of mineralization with manganese-enhanced magnetic resonance imaging

Science.gov (United States)

Chesnick, I.E.; Centeno, J.A.; Todorov, T.I.; Koenig, A.E.; Potter, K.

2011-01-01

Paramagnetic manganese can be employed as a calcium surrogate to sensitize the magnetic resonance imaging (MRI) technique to the processing of calcium during the bone formation process. At low doses, after just 48h of exposure, osteoblasts take up sufficient quantities of manganese to cause marked reductions in the water proton T1 values compared with untreated cells. After just 24h of exposure, 25??M MnCl2 had no significant effect on cell viability. However, for mineralization studies 100??M MnCl2 was used to avoid issues of manganese depletion in calvarial organ cultures and a post-treatment delay of 48h was implemented to ensure that manganese ions taken up by osteoblasts is deposited as mineral. All specimens were identified by their days in vitro (DIV). Using inductively coupled plasma optical emission spectroscopy (ICP-OES), we confirmed that Mn-treated calvariae continued to deposit mineral in culture and that the mineral composition was similar to that of age-matched controls. Notably there was a significant decrease in the manganese content of DIV18 compared with DIV11 specimens, possibly relating to less manganese sequestration as a result of mineral maturation. More importantly, quantitative T1 maps of Mn-treated calvariae showed localized reductions in T1 values over the calvarial surface, indicative of local variations in the surface manganese content. This result was verified with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We also found that ??R1 values, calculated by subtracting the relaxation rate of Mn-treated specimens from the relaxation rate of age-matched controls, were proportional to the surface manganese content and thus mineralizing activity. From this analysis, we established that mineralization of DIV4 and DIV11 specimens occurred in all tissue zones, but was reduced for DIV18 specimens because of mineral maturation with less manganese sequestration. In DIV25 specimens, active mineralization was observed for

Iron and manganese oxides modified maize straw to remove tylosin from aqueous solutions.

Science.gov (United States)

Yin, Yongyuan; Guo, Xuetao; Peng, Dan

2018-08-01

Maize straw modified by iron and manganese oxides was synthesized via a simple and environmentally friendly method. Three maize straw materials, the original maize straw, maize straw modified by manganese oxides and maize straw modified by iron and manganese oxides, were detected by SEM, BET, XPS, XRD and FTIR. The results showed that maize straw was successfully modified and maize straw modified by iron and manganese oxides has a larger surface area than MS. According to the experimental data, the sorption trend could conform to the pseudo-second-order kinetic model well, and the sorption ability of tylosin on sorbents followed the order of original maize straw oxides iron and manganese oxides. The study indicated that manganese oxides and iron-manganese oxides could significantly enhance the sorption capacity of original maize straw. The sorption isotherm data of tylosin on original maize straw fit a linear model well, while Freundlich models were more suitable for maize straw modified by manganese oxides and maize straw modified by iron and manganese oxides. The pH, ionic strength and temperature can affect the sorption process. The sorption mechanisms of tylosin on iron and manganese oxides modified maize straw were attribute to the surface complexes, electrostatic interactions, H bonding and hydrophobic interactions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of Manganese Content on the Fabrication of Porous Anodic Alumina

Directory of Open Access Journals (Sweden)

C. H. Voon

2012-01-01

Full Text Available The influence of manganese content on the formation of well-ordered porous anodic alumina was studied. Porous anodic alumina has been produced on aluminium substrate of different manganese content by single-step anodizing at 50 V in 0.3 M oxalic acid at 15°C for 60 minutes. The well-ordered pore and cell structure was revealed by subjecting the porous anodic alumina to oxide dissolution treatment in a mixture of chromic acid and phosphoric acid. It was found that the manganese content above 1 wt% impaired the regularity of the cell and pore structure significantly, which can be attributed to the presence of secondary phases in the starting material with manganese content above 1 wt%. The pore diameter and interpore distance decreased with the addition of manganese into the substrates. The time variation of current density and the thickness of porous anodic alumina also decreased as a function of the manganese content in the substrates.

Manganese dipyridoxyl diphosphate:

DEFF Research Database (Denmark)

H, Brurok; Ardenkjær-Larsen, Jan Henrik; G, Hansson

1999-01-01

Manganese dipyridoxyl diphosphate (MnDPDP) is a contrast agent for magnetic resonance imaging (MRI) of the liver. Aims of the study were to examine if MnDPDP possesses superoxide dismutase (SOD) mimetic activity in vitro, and if antioxidant protection can be demonstrated in an ex vivo rat heart...

Synthesis and characterization of monomeric manganese(II) and ...

African Journals Online (AJOL)

The geometry at the manganese center is seven-coordinate, and is best described as a capped trigonal pyramid with the water molecule forming the cap and the six nitrogen atoms of the tpen ligand occupying the pyramidal sites. The manganese atom and the water molecule lie on a crystallographic twofold axis.

Brain manganese, catecholamine turnover, and the development of startle in rats prenatally exposed to manganese

International Nuclear Information System (INIS)

Kontur, P.J.; Fechter, L.D.

1985-01-01

Manganese (Mn) can be neurotoxic when present in high concentrations. Neonatal animals show differential absorption, accumulation, and excretion of Mn relative to adults. If similar kinetic differences exist during gestation, then fetal animals may be susceptible to Mn neurotoxicity. The objective of this study was to examine maternal-fetal Mn transfer and the susceptibility of prenatal animals to Mn neurotoxicity. This was approached by studying the ability of Mn to cross the placenta and reach the fetal central nervous system using radiotracer and atomic absorption spectroscopy techniques. Manganese is thought to disrupt catecholamine neurotransmission in the central nervous system. This was examined in newborn rats by alpha-methyl-para-tyrosine induced catecholamine turnover and the development of the acoustic startle response. The results suggest that there are limits on fetal Mn accumulation under conditions of both normal and excessive dietary Mn levels. Manganese accumulation in the fetal brain after exposure to increased dietary Mn does not alter either dopamine or norepinephrine turnover or the development of the acoustic startle response. Excess Mn does not appear to be neurotoxic to fetal rats in spite of its limited accumulation in nervous tissue after gestational exposure

Activation of a water molecule coordinated to manganese: four study cases

International Nuclear Information System (INIS)

Lassalle-Kaiser, B.

2008-10-01

The daunting energy consumption of western societies calls for the development of renewable energies. Among them, hydrogen stands as a major candidate. The cleanest way of producing hydrogen is water electro- or photolysis. This reaction is carried out in natural photosynthesis by a manganese-oxo cluster, the functioning of which remains unknown. Insight into this mechanism would greatly help the search for low-cost water splitting catalysts. Our contribution to this field is the understanding of the fundamental processes that govern the activation of water by manganese complexes. This manuscript describes our attempts to generate electrochemically mononuclear manganese(IV) complexes bearing a fully deprotonated water molecule (oxo ligand). We have studied four different cases, which reflect different possible coordination spheres capable of stabilizing such species. In the first chapter, we will give a brief overview of the present energetic challenges faced by western societies. In the second chapter, we will present general considerations about manganese chemistry and a description of the structure and functioning of the water oxidizing enzyme. We will also describe the basic requirements for the splitting of water and present the goals of our work. In the third chapter, we will present the synthesis of a new family of tetradentate ligands, together with the synthesis and full characterization of the corresponding nickel(II) complexes. The first results obtained with the manganese analogue will also be shown. Chapter four presents the formation and the full characterization of a mononuclear manganese(IV)-oxo complex, by electrochemical oxidation of a manganese(II)-aqua complex. We will present different pathways to generate this species and show which intermediates are involved in this 2 e - , 2 H + reaction. Chapter five describes the formation of a mononuclear manganese(IV) complex, by electrochemical oxidation of a manganese(III)-hydroxo complex. The

Catalase-like activity studies of the manganese(II) adsorbed zeolites

Science.gov (United States)

Ćiçek, Ekrem; Dede, Bülent

2013-12-01

Preparation of manganese(II) adsorbed on zeolite 3A, 4A, 5A. AW-300, ammonium Y zeolite, organophilic, molecular sieve and catalase-like enzyme activity of manganese(II) adsorbed zeolites are reported herein. Firstly zeolites are activated at 873 K for two hours before contact manganese(II) ions. In order to observe amount of adsorption, filtration process applied for the solution. The pure zeolites and manganese(II) adsorbed zeolites were analysed by FT-IR. As a result according to the FT-IR spectra, the incorporation of manganese(II) cation into the zeolite structure causes changes in the spectra. These changes are expected particularly in the pseudolattice bands connected with the presence of alumino and silicooxygen tetrahedral rings in the zeolite structure. Furthermore, the catalytic activities of the Mn(II) adsorbed zeolites for the disproportionation of hydrogen peroxide were investigated in the presence of imidazole. The Mn(II) adsorbed zeolites display efficiency in the disproportion reactions of hydrogen peroxide, producing water and dioxygen in catalase-like activity.

Personality traits in persons with manganese poisoning

Energy Technology Data Exchange (ETDEWEB)

Platonov, A A

1976-10-01

Results of studies with the Minnesota Multiphasic Personality Inventory (MMPI) in 3 groups of arc welders with various degrees of manganese poisoning (22 symptom-free, 23 with functional disturbances, 55 with organic symptoms) and 50 controls were discussed. There was a close relation between the severity of the poisoning and quantitative and qualitative personality changes. Personality tests are considered a useful addition to the clinical diagnosis of chronic manganese poisoning.

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

Science.gov (United States)

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.

Rapid manganese removal from mine waters using an aerated packed-bed bioreactor.

Science.gov (United States)

Johnson, Karen L; Younger, Paul L

2005-01-01

In the UK, the Environmental Quality Standard for manganese has recently been lowered to 30 microg/L (annual average), which is less than the UK Drinking Water Inspectorate's Maximum Permitted Concentration Value (50 microg/L). Current passive treatment systems for manganese removal operate as open-air gravel-bed filters, designed to maximize either influent light and/or dissolved oxygen. This requires large areas of land. A novel enhanced bioremediation treatment system for manganese removal has been developed that consists of a passively aerated subsurface gravel bed. The provision of air at depth and the use of catalytic substrates help overcome the slow kinetics usually associated with manganese oxidation. With a residence time of only 8 h and an influent manganese concentration of approximately 20 mg/L, >95% of the manganese was removed. The treatment system also operates successfully at temperatures as low as 4 degrees C and in total darkness. These observations have positive implications for manganese treatment using this technique in both colder climates and where large areas of land are unavailable. Furthermore, as the operation of this passive treatment system continually generates fresh manganese oxyhydroxide, which is a powerful sorbent for most pollutant metals, it potentially has major ancillary benefits as a removal process for other metals, such as zinc.

Electron-tunneling observation of localized excited states in superconducting manganese-doped lead

International Nuclear Information System (INIS)

Tsang, J.; Ginsberg, D.M.

1980-01-01

We have made electron-tunneling measurements on a dilute, superconducting lead-manganese alloy. A well-defined structure was observed in the ac-conductance--voltage curves, indicating excited states within the BCS energy gap. These states were partially accounted for by Shiba theory when spin-dependent s-, p-, and d-wave scattering were included. The phase shifts used in doing that were the results of band calculations. The experimental data also show the existence of a broad background density of states in the energy gap, which cannot be accounted for by the theory

Adsorptive removal of manganese, arsenic and iron from groundwater

NARCIS (Netherlands)

Buamah, R.

2009-01-01

Arsenic, manganese and iron in drinking water at concentrations exceeding recommended guideline values pose health risks and aesthetic defects. Batch and pilot experiments on manganese adsorption equilibrium and kinetics using iron-oxide coated sand (IOCS), Aquamandix and other media have been

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

Science.gov (United States)

Aras, Neny Rasnyanti M.; Arcana, I. Made

2015-09-01

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm-1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate

Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

Energy Technology Data Exchange (ETDEWEB)

Aras, Neny Rasnyanti M., E-mail: neny.rasnyanti@gmail.com; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)

2015-09-30

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm{sup −1} which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese

Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

International Nuclear Information System (INIS)

Aras, Neny Rasnyanti M.; Arcana, I Made

2015-01-01

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm −1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese

Influence of oxalic acid on the dissolution kinetics of manganese oxide

Science.gov (United States)

Godunov, E. B.; Artamonova, I. V.; Gorichev, I. G.; Lainer, Yu. A.

2012-11-01

The kinetics and electrochemical processes of the dissolution of manganese oxides with various oxidation states in sulfuric acid solutions containing oxalate ion additives is studied under variable conditions (concentration, pH, temperature). The parameters favoring a higher degree of the dissolution of manganese oxides in acidic media are determined. The optimal conditions are found for the dissolution of manganese oxides in acidic media in the presence of oxalate ions. The mechanism proposed for the dissolution of manganese oxides in sulfuric acid solutions containing oxalic acid is based on the results of kinetic and electrochemical studies. The steps of the dissolution mechanism are discussed.

Role of manganese in the resistance of Micrococcus radiodurans to ionizing radiation

International Nuclear Information System (INIS)

Wierowski, J.V.

1980-01-01

Micrococcus radiodurans possesses a very high level of intracellular manganese compared to other organisms. This manganese content has previously been shown to participate in the exceptional ulraviolet radiation resistance of M. radiodurans. This study was undertaken to determine the role of manganese in the ionizing radiation resistant of M. radiodurans. The results indicate that manganese is essential for DNA degradation to occur during irradiation. Manganese has also proven essential for the second phase of post-irradiation thymine base damage removal. These factors work together to increase the rate of recovery from radiation damage, which is reflected in a larger Dq, D 37 and exponential portion of the survival curve of high Mn-grown cells

The effect of spices and manganese on meat starter culture activity.

Science.gov (United States)

Coventry, M J; Hickey, M W

1993-01-01

Three species, two proprietary spice blends and six starter preparations used in commercial salami manufacture were analysed for manganese and magnesium content. A mettwurst spices blend showed the highest levels of manganese (0·77 ppm expressed as effective product level assuming a 1% spice content) while mild and hot paprika and milano blend contained levels of manganese 1 4 - 1 3 lower. Magnesium levels for spices ranged from 3·14 to 25·81 ppm. Only two of the six meat starter cultures showed high levels of manganese (7·77 and 16·12 ppm as effective product level based on inoculation rate) while magnesium levels for all starter cultures did not exceed 0·37 ppm. The pH of salami products made with starter cultures containing no added manganese lagged behind that of products made with added mangenese (5 ppm) by 0·2 pH units at 48 h. The effect of manganese ions on the fermentation rate of starter bacteria was studied further in a salami model system, in the absence and presence of added spices. The mettwurst blend produced greatest stimulation and the milano the least. A level of 1·2 ppm of added manganese was sufficient to achieve an optimal (spices tested in the salami model system. Copyright © 1993. Published by Elsevier Ltd.

40 CFR 721.10011 - Barium calcium manganese strontium oxide.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium calcium...

The sorption of silver by poorly crystallized manganese oxides

Science.gov (United States)

Anderson, B.J.; Jenne, E.A.; Chao, T.T.

1973-01-01

The sorption of silver by poorly crystallized manganese oxides was studied using synthesized samples of three members of the manganous manganite (birnessite) group, of different chemical composition and crystallinity, and a poorly organized ??-MnO2. All four oxides sorbed significant quantities of silver. The manganous manganites showed the greatest sorption (up to 0.5 moles silver/mole MnOx at pH 7) while the ??-MnO2 showed the least (0.3 moles silver/ mole MnOx at pH 7). Sorption of silver was adequately described by the Langmuir equation over a considerable concentration range. The relationship failed at low pH values and high equilibrium silver concentrations. The sorption capacity showed a direct relationship with pH. However, the rate of increase of sorption capacity decreased at the higher pH values. Silver sorption maxima. were not directly related to surface area but appeared to vary with the amount of occluded sodium and potassium present in the manganese oxide. The important processes involved in the uptake of silver by the four poorly crystallized manganese oxides ara considered to be surface exchange for manganese, potassium and sodium as well as exchange for structural manganese, potassium and sodium. ?? 1973.

Lithium containing manganese dioxide (composite dimensional manganese oxide-CDMO) as a cathod active material for lithium secondary batteries

Energy Technology Data Exchange (ETDEWEB)

Furukawa, Nobuhiro; Noma, Toshiyuki; Teraji, Kazuo; Nakane, Ikuo; Yamamoto, Yuji; Saito, Toshihiko (Sanyo Electric Co., Ltd., Osaka, Japan)

1989-06-05

Manganese dioxide containing lithium ions in a solid matrix was investigated in the lithium nonaqueous cell. Li/sub x/MnO/sub 2+{delta}/ material prepared, with the thermal treatment, by the solid state reaction of manganese dioxide and lithium hydroxide, 7 to 3 in molar ratio, at the temperature of 375{sup 0}C in air for 20 hours, exhibited the rechargeability in the lithium nonaqueous cell. A discharging and changing cycle test, 0.14 or 0.26e/Mn in each of both the discharge and charge, was also made, with the use of a flat type cell, to demonstrate it in performance. Synthetic Li/sub x/MnO/sub 2+{delta}/ was discussed, in advantageous use for the secondary lithium cell, based on the discharging and charging characteristics. As a conclusion of the foregoing, composite dimensional manganese oxide is expected to be good as active material of positive electrode for the secondary lithium cell use. 11 refs., 11 figs., 3 tabs.

Preparation of Baking-Free Brick from Manganese Residue and Its Mechanical Properties

Directory of Open Access Journals (Sweden)

Ping Wang

2013-01-01

Full Text Available The increasing amount of waste residue produced during the electrolytic preparation process of manganese has nowadays brought about serious environmental problems. The research on utilization of manganese slag has been a hot spot around the world. The utilization of manganese slag is not only environment friendly, but also economically feasible. In the current work, a summarization of the main methods to produced building materials from manganese slag materials was given. Baking-free brick, a promising building material, was produced from manganese slag with the addition of quicklime and cement. The physical properties, chemical composition, and mechanical performances of the obtained samples were measured by several analyses and characterization methods. Then the influence of adding materials and molding pressure during the preparation of baking-free brick samples on their compressive strength properties was researched. It is concluded that the baking-free brick prepared from manganese residue could have excellent compressive strength performance under certain formula.

Manganese oxide micro-supercapacitors with ultra-high areal capacitance

Science.gov (United States)

Wang, Xu; Myers, Benjamin D.; Yan, Jian; Shekhawat, Gajendra; Dravid, Vinayak; Lee, Pooi See

2013-05-01

A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of manganese oxide and short diffusion distance between electrodes give an ultra-high areal capacitance of 56.3 mF cm-2 at a current density of 27.2 μA cm-2.A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of manganese oxide and short diffusion distance between electrodes give an ultra-high areal capacitance of 56.3 mF cm-2 at a current density of 27.2 μA cm-2. Electronic supplementary information (ESI) available: Experimental procedures; optical images of micro-supercapacitors; areal capacitances of samples M-0.3C, M-0.6C and M-0.9C; illustration of interdigital finger electrodes; Nyquist plot of Co(OH)2 deposited on micro-electrodes. See DOI: 10.1039/c3nr00210a

Neurobehavioral function in school-age children exposed to manganese in drinking water.

Science.gov (United States)

Oulhote, Youssef; Mergler, Donna; Barbeau, Benoit; Bellinger, David C; Bouffard, Thérèse; Brodeur, Marie-Ève; Saint-Amour, Dave; Legrand, Melissa; Sauvé, Sébastien; Bouchard, Maryse F

2014-12-01

Manganese neurotoxicity is well documented in individuals occupationally exposed to airborne particulates, but few data are available on risks from drinking-water exposure. We examined associations of exposure from concentrations of manganese in water and hair with memory, attention, motor function, and parent- and teacher-reported hyperactive behaviors. We recruited 375 children and measured manganese in home tap water (MnW) and hair (MnH). We estimated manganese intake from water ingestion. Using structural equation modeling, we estimated associations between neurobehavioral functions and MnH, MnW, and manganese intake from water. We evaluated exposure-response relationships using generalized additive models. After adjusting for potential confounders, a 1-SD increase in log10 MnH was associated with a significant difference of -24% (95% CI: -36, -12%) SD in memory and -25% (95% CI: -41, -9%) SD in attention. The relations between log10 MnH and poorer memory and attention were linear. A 1-SD increase in log10 MnW was associated with a significant difference of -14% (95% CI: -24, -4%) SD in memory, and this relation was nonlinear, with a steeper decline in performance at MnW > 100 μg/L. A 1-SD increase in log10 manganese intake from water was associated with a significant difference of -11% (95% CI: -21, -0.4%) SD in motor function. The relation between log10 manganese intake and poorer motor function was linear. There was no significant association between manganese exposure and hyperactivity. Exposure to manganese in water was associated with poorer neurobehavioral performances in children, even at low levels commonly encountered in North America.

Effects of aluminum and manganese on the growth of ectomycorrhizal fungi.

Science.gov (United States)

Thompson, G W; Medve, R J

1984-09-01

Cenococcum graniforme, Suillus luteus, Thelephora terrestris, and three isolates of Pisolithus tinctorius were cultured on modified Melin-Norkrans medium at pH 3.4 and adjusted to 0 to 500 ppm (0 to 500 mug/ml) of aluminum or manganese sulfate. Except for T. terrestris, which was intolerant of aluminum at 150 and 250 to 500 ppm, and P. tinctorius isolate 250, which was intolerant of aluminum at 450 ppm, all fungi showed some growth at all concentrations of aluminum. S. luteus was the most tolerant to aluminum. Manganese was less fungitoxic than aluminum, with all fungi showing at least 65% growth at 500 ppm as compared with the control. C. graniforme was not inhibited at any concentration of manganese, and S. luteus was only affected at 500 ppm. P. tinctorius isolate 230 showed no significant variation in growth when subjected to various concentrations of three forms of manganese salts. Significant differences in growth were detected in response to three aluminum salts, but no detectable pattern was apparent. Genotypic responses to aluminum and manganese were evident for P. tinctorius. Isolates 210 and 230 were more tolerant to manganese than was isolate 250. Aluminum tolerance was in the order of isolate 230 > 210 > 250. Results of in vitro studies concerning tolerance responses of ectomycorrhizal fungi to aluminum and manganese were not consistent with field observations of the successional sequence of these fungi on acid coal spoils.

Effects of aluminum and manganese on the growth of ectomycorrhizal fungi

Energy Technology Data Exchange (ETDEWEB)

Thompson, G.W.; Medve, R.J.

1984-09-01

Cenococcum graniforme, Suillus luteus, Thelephora terrestris, and three isolates of Pisolithus tinctorius were cultured on modified Melin-Norkrans medium at pH 3.4 and adjusted to 0 to 500 ppm (0 to 500 ..mu..g/ml) of aluminum or manganese sulfate. Except for T. terrestris, which was intolerant of aluminum at 150 and 250 to 500 ppm, and P. tinctorius isolate 250, which was intolerant of aluminum at 450 ppm, all fungi showed some growth at all concentrations of aluminum. S. luteus was the most tolerant to aluminum. Manganese was less fungitoxic than aluminum, with all fungi showing at least 65% growth at 500 ppm as compared with the control. C graniforme was not inhibited at any concentration of manganese, and S. luteus was only affected at 500 ppm. P. tinctorius isolate 230 showed no significant variation in growth when subjected to various concentrations of three forms of manganese salts. Significant differences in growth were detected in response to three aluminum salts, but no detectable pattern was apparent. Genotypic responses to aluminum and manganese were evident for P. tinctorius. Isolates 210 and 230 were more tolerant to manganese than was isolate 250. Aluminum tolerance was in the order of isolate 230 > 210 > 250. Results of in vitro studies concerning tolerance responses of ectomycorrhizal fungi to aluminum and manganese were not consistent with field observations of the successional sequence of these fungi on acid coal spoils. 43 references, 3 tables.

Manganese oxidation state mediates toxicity in PC12 cells

International Nuclear Information System (INIS)

Reaney, S.H.; Smith, D.R.

2005-01-01

The role of the manganese (Mn) oxidation state on cellular Mn uptake and toxicity is not well understood. Therefore, undifferentiated PC12 cells were exposed to 0-200 μM Mn(II)-chloride or Mn(III)-pyrophosphate for 24 h, after which cellular manganese levels were measured along with measures of cell viability, function, and cytotoxicity (trypan blue exclusion, medium lactate dehydrogenase (LDH), 8-isoprostanes, cellular ATP, dopamine, serotonin, H-ferritin, transferrin receptor (TfR), Mn-superoxide dismutase (MnSOD), and copper-zinc superoxide dismutase (CuZnSOD) protein levels). Exposures to Mn(III) >10 μM produced 2- to 5-fold higher cellular manganese levels than equimolar exposures to Mn(II). Cell viability and ATP levels both decreased at the highest Mn(II) and Mn(III) exposures (150-200 μM), while Mn(III) exposures produced increases in LDH activity at lower exposures (≥50 μM) than did Mn(II) (200 μM only). Mn(II) reduced cellular dopamine levels more than Mn(III), especially at the highest exposures (50% reduced at 200 μM Mn(II)). In contrast, Mn(III) produced a >70% reduction in cellular serotonin at all exposures compared to Mn(II). Different cellular responses to Mn(II) exposures compared to Mn(III) were also observed for H-ferritin, TfR, and MnSOD protein levels. Notably, these differential effects of Mn(II) versus Mn(III) exposures on cellular toxicity could not simply be accounted for by the different cellular levels of manganese. These results suggest that the oxidation state of manganese exposures plays an important role in mediating manganese cytotoxicity

Quantification of manganese in human hand bones: a feasibility study

Energy Technology Data Exchange (ETDEWEB)

Aslam; Pejovic-Milic, A; Chettle, D R; McNeill, F E [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, L8S 4K1 (Canada)], E-mail: aslamib@mcmaster.ca

2008-08-07

Manganese is both an essential element to human health and also toxic when humans are exposed to excessive levels, particularly by means of inhalation. Biological monitoring of manganese exposure is problematic. It is subject to homeostasis; levels in blood (or serum/plasma) reflect only the most recent exposure and rapidly return to within normal ranges, even when there has been a temporary excursion in response to exposure. In this context, we have been developing a non-invasive technique for measurement of manganese stored in bone, using in vivo neutron activation analysis. Following preliminary feasibility studies, the technique has been enhanced by two significant infrastructure advances. A specially designed irradiation facility serves to maximize the activation of manganese with respect to the dose of ionizing radiation. Secondly, an array of eight NaI(Tl) crystals provides a detection system with very close to 4{pi} geometry. This feasibility study, using neutron activation analysis to measure manganese in the bones of the hand, takes two features into account. Firstly, there is considerable magnesium present in the bone and this produces a spectral interference with the manganese. The {sup 26}Mg(n,{gamma}){sup 27}Mg reaction produces {gamma}-rays of 0.843 MeV from the decay of {sup 27}Mg, which interfere with the 0.847 MeV {gamma}-rays from the decay of {sup 56}Mn, produced by the {sup 55}Mn(n,{gamma}){sup 56}Mn reaction. Secondly, this work provides estimates of the levels of manganese to be expected in referent subjects. A revised estimate has been made from the most recent literature to explore the potential of the technique as 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. This report presents the enhancements to the neutron activation system, by which manganese can be measured, which resulted in a detection

Quantification of manganese in human hand bones: a feasibility study

International Nuclear Information System (INIS)

Aslam; Pejovic-Milic, A; Chettle, D R; McNeill, F E

2008-01-01

Manganese is both an essential element to human health and also toxic when humans are exposed to excessive levels, particularly by means of inhalation. Biological monitoring of manganese exposure is problematic. It is subject to homeostasis; levels in blood (or serum/plasma) reflect only the most recent exposure and rapidly return to within normal ranges, even when there has been a temporary excursion in response to exposure. In this context, we have been developing a non-invasive technique for measurement of manganese stored in bone, using in vivo neutron activation analysis. Following preliminary feasibility studies, the technique has been enhanced by two significant infrastructure advances. A specially designed irradiation facility serves to maximize the activation of manganese with respect to the dose of ionizing radiation. Secondly, an array of eight NaI(Tl) crystals provides a detection system with very close to 4π geometry. This feasibility study, using neutron activation analysis to measure manganese in the bones of the hand, takes two features into account. Firstly, there is considerable magnesium present in the bone and this produces a spectral interference with the manganese. The 26 Mg(n,γ) 27 Mg reaction produces γ-rays of 0.843 MeV from the decay of 27 Mg, which interfere with the 0.847 MeV γ-rays from the decay of 56 Mn, produced by the 55 Mn(n,γ) 56 Mn reaction. Secondly, this work provides estimates of the levels of manganese to be expected in referent subjects. A revised estimate has been made from the most recent literature to explore the potential of the technique as 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. This report presents the enhancements to the neutron activation system, by which manganese can be measured, which resulted in a detection limit in the hand of human subjects of 1.6 �

Preparation and characterization of amorphous manganese sulfide thin films by SILAR method

International Nuclear Information System (INIS)

Pathan, H.M.; Kale, S.S.; Lokhande, C.D.; Han, Sung-Hwan; Joo, Oh-Shim

2007-01-01

Manganese sulfide thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method using manganese acetate as a manganese and sodium sulfide as sulfide ion sources, respectively. Manganese sulfide films were characterized for their structural, surface morphological and optical properties by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The as-deposited film on glass substrate was amorphous. The optical band gap of the film was found to be thickness dependent. As thickness increases optical band gap was found to be increase. The water angle contact was found to be 34 o , suggesting hydrophilic nature of manganese sulfide thin films. The presence of Mn and S in thin film was confirmed by energy dispersive X-ray analysis

Low copper and high manganese levels in prion protein plaques

Science.gov (United States)

Johnson, Christopher J.; Gilbert, P.U.P.A.; Abrecth, Mike; Baldwin, Katherine L.; Russell, Robin E.; Pedersen, Joel A.; McKenzie, Debbie

2013-01-01

Accumulation of aggregates rich in an abnormally folded form of the prion protein characterize the neurodegeneration caused by transmissible spongiform encephalopathies (TSEs). The molecular triggers of plaque formation and neurodegeneration remain unknown, but analyses of TSE-infected brain homogenates and preparations enriched for abnormal prion protein suggest that reduced levels of copper and increased levels of manganese are associated with disease. The objectives of this study were to: (1) assess copper and manganese levels in healthy and TSE-infected Syrian hamster brain homogenates; (2) determine if the distribution of these metals can be mapped in TSE-infected brain tissue using X-ray photoelectron emission microscopy (X-PEEM) with synchrotron radiation; and (3) use X-PEEM to assess the relative amounts of copper and manganese in prion plaques in situ. In agreement with studies of other TSEs and species, we found reduced brain levels of copper and increased levels of manganese associated with disease in our hamster model. We also found that the in situ levels of these metals in brainstem were sufficient to image by X-PEEM. Using immunolabeled prion plaques in directly adjacent tissue sections to identify regions to image by X-PEEM, we found a statistically significant relationship of copper-manganese dysregulation in prion plaques: copper was depleted whereas manganese was enriched. These data provide evidence for prion plaques altering local transition metal distribution in the TSE-infected central nervous system.

Manganese and iron oxidation by fungi isolated from building stone.

Science.gov (United States)

de la Torre, M A; Gomez-Alarcon, G

1994-01-01

Acid and nonacid generating fungal strains isolated from weathered sandstone, limestone, and granite of Spanish cathedrals were assayed for their ability to oxidize iron and manganese. In general, the concentration of the different cations present in the mineral salt media directly affected Mn(IV) oxide formation, although in some cases, the addition of glucose and nitrate to the culture media was necessary. Mn(II) oxidation in acidogenic strains was greater in a medium containing the highest concentrations of glucose, nitrate, and manganese. High concentrations of Fe(II), glucose, and mineral salts were optimal for iron oxidation. Mn(IV) precipitated as oxides or hydroxides adhered to the mycelium. Most of the Fe(III) remained in solution by chelation with organic acids excreted by acidogenic strains. Other metabolites acted as Fe(III) chelators in nonacidogenic strains, although Fe(III) deposits around the mycelium were also detected. Both iron and manganese oxidation were shown to involve extracellular, hydrosoluble enzymes, with maximum specific activities during exponential growth. Strains able to oxidize manganese were also able to oxidize iron. It is concluded that iron and manganese oxidation reported in this work were biologically induced by filamentous fungi mainly by direct (enzymatic) mechanisms.

Beneficiation studies of Bajaur manganese ore by different processing techniques

International Nuclear Information System (INIS)

Riaz, M.; Khan, F.U.; Yamin, A.; Bilquees, R.; Muhammad, N.

2010-01-01

The manganese ore of Bajaur Agency of Pakistan was subjected to flotation, heavy medium separation, gravity concentration and magnetic separation techniques for beneficiation. The original composition of the manganese ore was 45.56% Mn , 4% Fe/sub 2/O/sub 3/, 40% SiO/sub 2/. The Mn content was raised to a maximum 48.76 % in the concentrate with the recovery of 67.78 % through flotation technique. Other techniques rendered marginal increase in Mn concentration against the theoretical possibility of substantial enrichment by rejecting the 20 % gangue minerals. The separation of manganese minerals from associated gangue was difficult, due to mineralogical complexity of the ore, extreme fineness of the particle size, texture and minerals intergrowth. High Mn/Fe ratio, phosphorus, and silica contents were within tolerable limits for utilisation of the ore in ferro-manganese production. (author)

Interleukin-6 counteracts therapy-induced cellular oxidative stress in multiple myeloma by up-regulating manganese superoxide dismutase.

Science.gov (United States)

Brown, Charles O; Salem, Kelley; Wagner, Brett A; Bera, Soumen; Singh, Neeraj; Tiwari, Ajit; Choudhury, Amit; Buettner, Garry R; Goel, Apollina

2012-06-15

IL (interleukin)-6, an established growth factor for multiple myeloma cells, induces myeloma therapy resistance, but the resistance mechanisms remain unclear. The present study determines the role of IL-6 in re-establishing intracellular redox homoeostasis in the context of myeloma therapy. IL-6 treatment increased myeloma cell resistance to agents that induce oxidative stress, including IR (ionizing radiation) and Dex (dexamethasone). Relative to IR alone, myeloma cells treated with IL-6 plus IR demonstrated reduced annexin/propidium iodide staining, caspase 3 activation, PARP [poly(ADP-ribose) polymerase] cleavage and mitochondrial membrane depolarization with increased clonogenic survival. IL-6 combined with IR or Dex increased early intracellular pro-oxidant levels that were causally related to activation of NF-κB (nuclear factor κB) as determined by the ability of N-acetylcysteine to suppress both pro-oxidant levels and NF-κB activation. In myeloma cells, upon combination with hydrogen peroxide treatment, relative to TNF (tumour necrosis factor)-α, IL-6 induced an early perturbation in reduced glutathione level and increased NF-κB-dependent MnSOD (manganese superoxide dismutase) expression. Furthermore, knockdown of MnSOD suppressed the IL-6-induced myeloma cell resistance to radiation. MitoSOX Red staining showed that IL-6 treatment attenuated late mitochondrial oxidant production in irradiated myeloma cells. The present study provides evidence that increases in MnSOD expression mediate IL-6-induced resistance to Dex and radiation in myeloma cells. The results of the present study indicate that inhibition of antioxidant pathways could enhance myeloma cell responses to radiotherapy and/or chemotherapy.

The effect of adding urea, manganese and linoleic acid to wheat straw and wood chips on lignin degradation by fungi and subsequent

NARCIS (Netherlands)

Kuijk, van S.J.A.; Sonnenberg, A.S.M.; Baars, J.J.P.; Hendriks, W.H.; Cone, J.W.

2016-01-01

The aim of this study was optimizing Ceriporiopsis subvermispora and Lentinula edodes pre-treatment of wheat straw and wood chips by adding urea, manganese and linoleic acid. Optimization was defined as more lignin degradation and an increase in in vitro gas

Iron and manganese oxide mineralization in the Pacific

Science.gov (United States)

Hein, J. R.; Koschinsky, A.; Halbach, P.; Manheim, F. T.; Bau, M.; Jung-Keuk, Kang; Lubick, N.

1997-01-01

Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. These processes are discussed.

The Escherichia coli small protein MntS and exporter MntP optimize the intracellular concentration of manganese.

Directory of Open Access Journals (Sweden)

Julia E Martin

2015-03-01

Full Text Available Escherichia coli does not routinely import manganese, but it will do so when iron is unavailable, so that manganese can substitute for iron as an enzyme cofactor. When intracellular manganese levels are low, the cell induces the MntH manganese importer plus MntS, a small protein of unknown function; when manganese levels are high, the cell induces the MntP manganese exporter and reduces expression of MntH and MntS. The role of MntS has not been clear. Previous work showed that forced MntS synthesis under manganese-rich conditions caused bacteriostasis. Here we find that when manganese is scarce, MntS helps manganese to activate a variety of enzymes. Its overproduction under manganese-rich conditions caused manganese to accumulate to very high levels inside the cell; simultaneously, iron levels dropped precipitously, apparently because manganese-bound Fur blocked the production of iron importers. Under these conditions, heme synthesis stopped, ultimately depleting cytochrome oxidase activity and causing the failure of aerobic metabolism. Protoporphyrin IX accumulated, indicating that the combination of excess manganese and iron deficiency had stalled ferrochelatase. The same chain of events occurred when mutants lacking MntP, the manganese exporter, were exposed to manganese. Genetic analysis suggested the possibility that MntS exerts this effect by inhibiting MntP. We discuss a model wherein during transitions between low- and high-manganese environments E. coli uses MntP to compensate for MntH overactivity, and MntS to compensate for MntP overactivity.

Preparation of the electrochemically formed spinel-lithium manganese oxides

Energy Technology Data Exchange (ETDEWEB)

Katakura, Katsumi; Wada, Kohei; Kajiki, Yoshiyuki; Yamamoto, Akiko [Department of Chemical Engineering, Nara National College of Technology, 22 Yata-cho Yamotokoriyama, Nara 639-1080 (Japan); Ogumi, Zempachi [Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

2009-04-01

Electrochemically formed spinel-lithium manganese oxides were synthesized from manganese hydroxides prepared by a cathodic electrochemical precipitation from various concentrations of manganese nitrate solutions. Two types of manganese hydroxides were formed from diluted and concentrated Mn(NO{sub 3}){sub 2} aqueous solutions. Uniform and equi-sized disk shaped Mn(OH){sub 2} crystals of 0.2-5 {mu}m in diameter were obtained on a Pt substrate after the electrochemical precipitation from lower concentration of ranging from 2 mmol dm{sup -3} to 2 mol dm{sup -3} Mn(NO{sub 3}){sub 2} aq., while the grass blade-like precipitate which is ascribed to manganese hydroxide with 20-80 {mu}m long and 1-5 {mu}m wide were formed from concentrated Mn(NO{sub 3}){sub 2} aq. Both manganese hydroxides gave the electrochemically formed spinel-LiMn{sub 2}O{sub 4} onto a Pt sheet, which is ready for electrochemical measurement, after calcination of the Li incorporated precipitate at 750 C without any additives. While the shape and size of the secondary particle frameworks (aggregates) of the electrochemically formed spinel-LiMn{sub 2}O{sub 4} can be controlled by the electrolysis conditions, the nanostructured primary crystals of 200 nm in diameter were obtained in all cases except that the fiber-like nanostructured spinel-LiMn{sub 2}O{sub 4} crystals with 200 nm in diameter were obtained from concentrated Mn(NO{sub 3}){sub 2} aq. Though these two types of electrochemically formed spinel-LiMn{sub 2}O{sub 4} showed well-shaped CVs even in higher scan rates, it would be suitable for high power density battery applications. These behaviors are assumed to be ascribed to the crystal size and shape of the processed spinel-LiMn{sub 2}O{sub 4}. (author)

Thermodynamic Interactions Among Carbon, Silicon and Iron in Carbon Saturated Manganese Melts

International Nuclear Information System (INIS)

Paek, Min-Kyu; Lee, Won-Kyu; Jin, Jinan; Jang, Jung-Mock; Pak, Jong-Jin

2012-01-01

Thermodynamics of carbon in manganese alloy melts is important in manufacturing low carbon ferromanganese and silico-manganese alloys. In order to predict the carbon solubility in liquid Mn-Si-Fe-Csat alloys as a function of melt composition and temperature, thermodynamic interactions among carbon, silicon and iron in carbon saturated liquid manganese should be known. In the present study, the effects of silicon and iron on the carbon solubility in Mn-Si, Mn-Fe and Mn-Si-Fe melts were measured in the temperature range from 1673 to 1773 K. The carbon solubility decreases significantly as silicon and iron contents increase in liquid manganese alloy. The interaction parameters among carbon, silicon and iron in carbon saturated liquid manganese were determined from the carbon solubility data and the Lupis' relation for the interaction coefficient at constant activity.

Factors affecting radium removal using mixed iron-manganese oxides

International Nuclear Information System (INIS)

Mott, H.V. Singh, S.; Kondapally, V.R.

1993-01-01

Batch experiments confirmed that sorption of radium by a mixed iron-manganese oxide solid phase shows promise for treating radium-contaminated water. The capacities of these mixed oxides for sorption of radium depend on the composition of the solid phase, the pH of the aqueous solution, and the presence of competing cations. The removal of the oxide-radium complexes from aqueous suspension by manganese greensand filtration was also investigated. It was found that influent radium concentrations of 100 pCi/L were reduced to 2--9 pCi/L by this process. Additional study of the fate of radium in manganese greensand filters is recommended before this procedure is used for drinking water treatment

Factors affecting radium removal using mixed iron-manganese oxides

Energy Technology Data Exchange (ETDEWEB)

Mott, H.V. Singh, S.; Kondapally, V.R. (South Dakota School of Mines and Technology, Rapid City, SD (United States))

1993-10-01

Batch experiments confirmed that sorption of radium by a mixed iron-manganese oxide solid phase shows promise for treating radium-contaminated water. The capacities of these mixed oxides for sorption of radium depend on the composition of the solid phase, the pH of the aqueous solution, and the presence of competing cations. The removal of the oxide-radium complexes from aqueous suspension by manganese greensand filtration was also investigated. It was found that influent radium concentrations of 100 pCi/L were reduced to 2--9 pCi/L by this process. Additional study of the fate of radium in manganese greensand filters is recommended before this procedure is used for drinking water treatment.

Manganese: it turns iron into steel (and does so much more)

Science.gov (United States)

Cannon, William F.

2014-01-01

Manganese is a common ferrous metal with atomic weight of 25 and the chemical symbol Mn. It constitutes roughly 0.1 percent of the Earth’s crust, making it the 12th most abundant element. Its early uses were limited largely to pigments and oxidants in chemical processes and experiments, but the significance of manganese to human societies exploded with the development of modern steelmaking technology in the 1860s. U.S consumption of manganese is about 500,000 metric tons each year, predominantly by the steel industry. Because manganese is essential and irreplaceable in steelmaking and its global mining industry is dominated by just a few nations, it is considered one of the most critical mineral commodities for the United States.

Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel

Directory of Open Access Journals (Sweden)

S. Ilaiyavel

2013-03-01

Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.

Relationship between blood manganese and blood pressure in the Korean general population according to KNHANES 2008

International Nuclear Information System (INIS)

Lee, Byung-Kook; Kim, Yangho

2011-01-01

Introduction: We present data on the association of manganese (Mn) level with hypertension in a representative sample of the adult Korean population who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) 2008. Methods: This study was based on the data obtained by KNHANES 2008, which was conducted for three years (2007-2009) using a rolling sampling design involving a complex, stratified, multistage, probability-cluster survey of a representative sample of the noninstitutionalized civilian population of South Korea. Results: Multiple regression analysis after controlling for covariates, including gender, age, regional area, education level, smoking, drinking status, hemoglobin, and serum creatinine, showed that the beta coefficients of log blood Mn were 3.514, 1.878, and 2.517 for diastolic blood pressure, and 3.593, 2.449, and 2.440 for systolic blood pressure in female, male, and all participants, respectively. Multiple regression analysis including three other blood metals, lead, mercury, and cadmium, revealed no significant effects of the three metals on blood pressure and showed no effect on the association between blood Mn and blood pressure. In addition, doubling the blood Mn increased the risk of hypertension 1.828, 1.573, and 1.567 fold in women, men, and all participants, respectively, after adjustment for covariates. The addition of blood lead, mercury, and cadmium as covariates did not affect the association between blood Mn and the prevalence of hypertension. Conclusion: Blood Mn level was associated with an increased risk of hypertension in a representative sample of the Korean adult population. - Highlights: → We showed the association of manganese with hypertension in Korean population. → This study was based on the data obtained by KNHANES 2008. → Blood manganese level was associated with an increased risk of hypertension.

Manganese phospate physical chemistry and surface properties

International Nuclear Information System (INIS)

Najera R, N.; Romero G, E. T.

2008-01-01

This paper presents the methodology for the manganese phosphate (III) synthesis (MnP0 4 H 2 0) from manganese chloride. The physicochemical characterization was carried out by: X-ray diffraction, scanning electron microscopy, infrared analysis and thermal gravimetric analysis. The surface characterization is obtained through the determination of surface area, point of zero charge and kinetics of moisture. As a phosphate compound of a metal with low oxidation state is a promising compound for removal pollutants from water and soil, can be used for the potential construction of containment barriers for radioactive wastes. (Author)

Low power loss and field-insensitive permeability of Fe-6.5%Si powder cores with manganese oxide-coated particles

Energy Technology Data Exchange (ETDEWEB)

Li, Junnan, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Wang, Xian; Xu, Xiaojun; Gong, Rongzhou, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Feng, Zekun [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Yajie; Harris, V. G. [Department of Electrical and Computer Engineering, Center for Microwave Magnetic Materials and Integrated Circuits, Northeastern University, Boston, Massachusetts 02115 (United States)

2015-05-07

Fe-6.5%Si alloy powders coated with manganese oxides using an innovative in situ process were investigated. The in-situ coating of the insulating oxides was realized with a KMnO{sub 4} solution by a chemical process. The insulating manganese oxides with mixed valance state were verified by X-ray photoelectron spectroscopy analysis. The thickness of the insulating layer on alloy particles was determined to be in a range of 20–210 nm, depending upon the KMnO{sub 4} concentration. The powder core loss and the change in permeability under a DC-bias field were measured at frequencies ranging from 50 to 100 kHz. The experiments indicated that the Fe-6.5%Si powder cores with a 210 nm-thick manganese oxide layer not only showed a low core loss of 459 mW/cm{sup 3} at 100 kHz but also showed a small reduction in permeability (μ(H)/μ(0) = 85% for μ = 42) at a DC-bias field of 80 Oe. This work has defined a novel pathway to realizing low core loss and field-insensitive permeability for Fe-Si powder cores.

Manganese(II) chelate contrast media

International Nuclear Information System (INIS)

Rocklage, S.M.; Quay, S.C.

1994-01-01

New chelate forming compounds for use as contrast media in NMR imaging are described. Especially mentioned are manganese(II) ion chelates of N,N' dipyridoxaldiamine, N,N' diacetic acid, and salts and esters thereof. 1 fig

Manganese oxide-based multifunctionalized mesoporous silica nanoparticles for pH-responsive MRI, ultrasonography and circumvention of MDR in cancer cells.

Science.gov (United States)

Chen, Yu; Yin, Qi; Ji, Xiufeng; Zhang, Shengjian; Chen, Hangrong; Zheng, Yuanyi; Sun, Yang; Qu, Haiyun; Wang, Zheng; Li, Yaping; Wang, Xia; Zhang, Kun; Zhang, Linlin; Shi, Jianlin

2012-10-01

Nano-biotechnology has been introduced into cancer theranostics by engineering a new generation of highly versatile hybrid mesoporous composite nanocapsules (HMCNs) for manganese-based pH-responsive dynamic T(1)-weighted magnetic resonance imaging (MRI) to efficiently respond and detect the tumor acidic microenvironment, which was further integrated with ultrasonographic function based on the intrinsic unique hollow nanostructures of HMCNs for potentially in vitro and in vivo dual-modality cancer imaging. The manganese oxide-based multifunctionalization of hollow mesoporous silica nanoparticles was achieved by an in situ redox reaction using mesopores as the nanoreactors. Due to the dissolution nature of manganese oxide nanoparticles under weak acidic conditions, the relaxation rate r(1) of manganese-based mesoporous MRI-T(1) contrast agents (CAs) could reach 8.81 mM(-1)s(-1), which is a 11-fold magnitude increase compared to the neutral condition, and is almost two times higher than commercial Gd(III)-based complex agents. This is also the highest r(1) value ever reported for manganese oxide nanoparticles-based MRI-T(1) CAs. In addition, the hollow interiors and thin mesoporous silica shells endow HMCNs with the functions of CAs for efficient in vitro and in vivo ultrasonography under both harmonic- and B-modes. Importantly, the well-defined mesopores and large hollow interiors of HMCNs could encapsulate and deliver anticancer agents (doxorubicin) intracellularly to circumvent the multidrug resistance (MDR) of cancer cells and restore the anti-proliferative effect of drugs by nanoparticle-mediated endocytosis process, intracellular drug release and P-gp inhibition/ATP depletion in cancer cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

Manganese kinetics in the shore crab Carcinus maenas exposed via food and water

International Nuclear Information System (INIS)

Bjerregaard, P.; Hastrup, M.

1999-01-01

Oxygen depletion in marine water has been an increasing problem in many coastal areas due to eutrophication. Under hypoxic and anoxic conditions in bottom waters, the flux of manganese out of the sediment increases and substantial concentrations of dissolved manganese in the water column can be reached. Manganese liberated as Mn ++ from the sediment during hypoxic conditions is re-oxidised fairly slowly (in order of weeks) after reintroduction of oxygen to the water. Therefore, benthic organisms may encounter concurrent exposure to increased manganese concentrations and hypoxic condition

The INEL beryllium multiplication experiment

International Nuclear Information System (INIS)

Smith, J.R.; King, J.J.

1991-03-01

The experiment to measure the multiplication of 14-MeV neutrons in bulk beryllium has been completed. The experiment consists of determining the ratio of 56 Mn activities induced in a large manganese bath by a central 14-MeV neutron source, with and without a beryllium sample surrounding the source. In the manganese bath method a neutron source is placed at the center of a totally-absorbing aqueous solution of MnSo 4 . The capture of neutrons by Mn produces a 56 Mn activity proportional to the emission rate of the source. As applied to the measurement of the multiplication of 14- MeV neutrons in bulk beryllium, the neutron source is a tritium target placed at the end of the drift tube of a small deuteron accelerator. Surrounding the source is a sample chamber. When the sample chamber is empty, the neutrons go directly to the surrounding MnSO 4 solution, and produce a 56 Mn activity proportional to the neutron emission rate. When the chamber contains a beryllium sample, the neutrons first enter the beryllium and multiply through the (n,2n) process. Neutrons escaping from the beryllium enter the bath and produce a 56 Mn activity proportional to the neutron emission rate multiplied by the effective value of the multiplication in bulk beryllium. The ratio of the activities with and without the sample present is proportional to the multiplication value. Detailed calculations of the multiplication and all the systematic effects were made with the Monte Carlo program MCNP, utilizing both the Young and Stewart and the ENDF/B-VI evaluations for beryllium. Both data sets produce multiplication values that are in excellent agreement with the measurements for both raw and corrected values of the multiplication. We conclude that there is not real discrepancy between experimental and calculated values for the multiplication of neutrons in bulk beryllium. 12 figs., 11 tabs., 18 refs

Behavior of manganese ion in basic medium: consequence for the ...

African Journals Online (AJOL)

Dr. J. T. Ekanem

2006-01-25

Jan 25, 2006 ... adding manganese chloride or manganese sulfate to sodium hydroxyde or sodium carbonate in aqueous ... carbonate (1 M). The release of p- nitrophenoxide anion (pNP) was quantified at. 420 nm using a spectrophotometer (Spectronic. Genesis 5). .... These curves were bell-type with an ascending.

Characterization of chloroplast phosphoproteins controlling manganese use efficiency using quantitative proteomics

DEFF Research Database (Denmark)

Petersen, Jørgen; Sprenger, Richard Remko; Rogowska-Wrzesinska, Adelina

Manganese is important for molecular functions in plants, i.e. as a co-factor in enzymes and in the oxygen evolving complex of photosystem II, located like most of the photosynthetic machinery, in the thylakoid membranes of chloroplasts. Soils that lack plant available micronutrients such as mang......Manganese is important for molecular functions in plants, i.e. as a co-factor in enzymes and in the oxygen evolving complex of photosystem II, located like most of the photosynthetic machinery, in the thylakoid membranes of chloroplasts. Soils that lack plant available micronutrients...... involved in manganese use efficiency, focusing on the phosphoproteome from thylakoid preparations from two barley genotypes, manganese efficient (Vanessa) and inefficient (Antonia) genotype. Experimental: By monitoring the photosynthetic efficiency (Fv/Fm) a decline in activity is observed as a consequence...

Manganese and selenium concentrations in cerebrospinal fluid of seriously ill children.

Science.gov (United States)

Franěk, Tomáš; Kotaška, Karel; Průša, Richard

2017-11-01

The homeostasis of essential trace elements such as selenium and manganese may be altered in patients with severe diseases of various etiologies (trauma brain injuries, tumors, leukemias, lymphomas, neurological diseases). Concentration of manganese and selenium were determined in cerebrospinal fluid by electrothermal atomic absorption spectrometry in 50 hospitalized children with various clinical ethiologies including oncological, neurological, and brain related diseases. The concentrations of manganese in cerebrospinal fluid of children were 0.97±0.67 μg/L. The concentrations of selenium were 13.3±3.5 μg/L. The concentrations were similar as published in adults. The values did not correlated with the age, gender and severity of the disease. We evaluated values of selenium and manganese in cerebrospinal fluid of seriously diseased children. © 2017 Wiley Periodicals, Inc.

Organometallic complexes of thiocarbanilides and substituted thiocarbanilides using manganese (II) chloride

International Nuclear Information System (INIS)

Babiker, Musa Elaballa Mohamed

2000-01-01

Organo-metallic complexes of substituted thiocarbanilide using manganese (II) chloride were prepared, these are: (VIII) 3:3'-Dichloro thiocarbanilide. Manganese (II) chloride. (IX) 3:3'-Dimethyl thiocarbanilide. Manganese (II) chloride. (X) 2:2'-dimethyl thiocarbanilide. Manganese (II) chloride. These compounds are coloured, soluble in most organic solvents, insoluble in water, decomposed by hot solvents. The physical properties of compounds (IX) and (X) were studied by UV and IR spectra, and the physical properties of compound (VIII) were studied by UV, IR, mass spectra and NMR. The molecular weight of the compound (VIII) was determined by three different methods; Rast's camphor method, mass spectra and the nitrogen contents. The stoichiometry of the reaction was found to be 2:1, and the coordination is from sulphur atom more than nitrogen.(Author)

Characteristics and treatment mechanism of mine water with high concentration of iron and manganese

Energy Technology Data Exchange (ETDEWEB)

Li, F.; Yang, J.; He, X.; Yang, J.; Tian, T. [Hebei University of Engineering, Handan (China)

2006-12-15

The characteristics and treatment of mine water with high concentration or iron and manganese were studied with mine water produced in Jiukuang and Siwan belonging to Hebi Coal Industry Group Co., Ltd. Analysis shows that the mine water is abundant in dissolved oxygen and has high TDS and high turbidity so the mine water does not need aeration. The effect of removal of iron and manganese by coagulation-sedimentation and the influence of filter material and influent water flow rate on effluent quality were investigated. It is shown that the removal rate of iron can reach 90% while removal of manganese can only reach about 20%. The concentration of iron and manganese in the effluent is lower than 0.1 mg/L with filter material of manganese sand which was immersed in KMnO{sub 4} solution at a filtration rate of 7 - 9 m/h. The results show that the layer of activated compound substance membrane formed on the surface of the manganese sand plays an important role in the removal of manganese. 7 refs., 2 figs., 3 tabs.

Spectroscopic characterization of manganese minerals.

Science.gov (United States)

Lakshmi Reddy, S; Padma Suvarna, K; Udayabhaska Reddy, G; Endo, Tamio; Frost, R L

2014-01-03

Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals. Copyright © 2013 Elsevier B.V. All rights reserved.

Bioconcentration of manganese and iron in Panaeoloideae Sing

OpenAIRE

Stijve, T.; Blake, C.

1994-01-01

According to literature, the manganese content of most basidiomycetes fluctuates between 10 and 60 mg/kg, whereas the iron levels range from 100-500 mg/kg (both expressed on dry weight). The present authors report that bioconcentration of manganese is a distinguishing feature of the Panaeoloideae, as demonstrated by the analysis of 44 collections representing 15 taxons. Carpophores generally contain between 250 and 2500 mg/kg on dry weight, and, with the notable exception of Panaeolus semiova...

Synthesis of condensed double rubidium manganese phosphates in melts of polyphosphoric acids

International Nuclear Information System (INIS)

Guzeeva, L.S.; Tananaev, I.V.

1988-01-01

The aim of this work was to study the character of the reaction of MnO 2 and Rb 2 O with melts of polyphosphoric acids, and to establish the composition and the conditions of formation of the condensed double rubidium manganese phosphates. In the reaction of manganese and rubidium oxides with melts of polyphosphoric acids at 140-350 degree C, three types of trivalent manganese and rubidium condensed double phosphates are formed - diphosphates RbMn(H 2 P 2 O 7 ) and Rb 2 MnH 3 (P 2 O 7 ) 2 , triphosphate RbMnHP 3 O 10 and diphosphate RbMnP 2 O 7 - in addition to a double cyclotriphosphate of divalent manganese with rubidium RbMnP 3 O 9 . The thermal transformations of the compound isolated were studied. It was shown that rubidium manganese cyclotriphosphate can be obtained by the thermal decomposition of the diphosphate RbMn(H 2 P 2 O 7 ) 2

Polydisulfide Manganese(II) Complexes as Non-Gadolinium Biodegradable Macromolecular MRI Contrast Agents

Science.gov (United States)

Ye, Zhen; Jeong, Eun-Kee; Wu, Xueming; Tan, Mingqian; Yin, Shouyu; Lu, Zheng-Rong

2011-01-01

Purpose To develop safe and effective manganese(II) based biodegradable macromolecular MRI contrast agents. Materials and Methods In this study, we synthesized and characterized two polydisulfide manganese(II) complexes, Mn-DTPA cystamine copolymers and Mn-EDTA cystamine copolymers, as new biodegradable macromolecular MRI contrast agents. The contrast enhancement of the two manganese based contrast agents were evaluated in mice bearing MDA-MB-231 human breast carcinoma xenografts, in comparison with MnCl2. Results The T1 and T2 relaxivities were 4.74 and 10.38 mM−1s−1 per manganese at 3T for Mn-DTPA cystamine copolymers (Mn=30.50 kDa) and 6.41 and 9.72 mM−1s−1 for Mn-EDTA cystamine copolymers (Mn= 61.80 kDa). Both polydisulfide Mn(II) complexes showed significant liver, myocardium and tumor enhancement. Conclusion The manganese based polydisulfide contrast agents have a potential to be developed as alternative non-gadolinium contrast agents for MR cancer and myocardium imaging. PMID:22031457

Biological manganese removal from acid mine drainage in constructed wetlands and prototype bioreactors.

Science.gov (United States)

Hallberg, Kevin B; Johnson, D Barrie

2005-02-01

Mine drainage waters vary considerably in the range and concentration of heavy metals they contain. Besides iron, manganese is frequently present at elevated concentrations in waters draining both coal and metal mines. Passive treatment systems (aerobic wetlands and compost bioreactors) are designed to remove iron by biologically induced oxidation/precipitation. Manganese, however, is problematic as it does not readily form sulfidic minerals and requires elevated pH (>8) for abiotic oxidation of Mn (II) to insoluble Mn (IV). As a result, manganese removal in passive remediation systems is often less effective than removal of iron. This was found to be the case at the pilot passive treatment plant (PPTP) constructed to treat water draining the former Wheal Jane tin mine in Cornwall, UK, where effective removal of manganese occurred only in one of the three rock filter components of the composite systems over a 1-year period of monitoring. Water in the two rock filter systems where manganese removal was relatively poor was generally system. These differences in water chemistry and manganese removal were due to variable performances in the compost bioreactors that feed the rock filter units in the composite passive systems at Wheal Jane. An alternative approach for removing soluble manganese from mine waters, using fixed bed bioreactors, was developed. Ferromanganese nodules (about 2 cm diameter), collected from an abandoned mine adit in north Wales, were used to inoculate the bioreactors (working volume ca. 700 ml). Following colonization by manganese-oxidizing microbes, the aerated bioreactor catalysed the removal of soluble manganese, via oxidation of Mn (II) and precipitation of the resultant Mn (IV) in the bioreactor, in synthetic media and mine water from the Wheal Jane PPTP. Such an approach has potential application for removing soluble Mn from mine streams and other Mn-contaminated water courses.

Selective Synthesis of Manganese/Silicon Complexes in Supercritical Water

Directory of Open Access Journals (Sweden)

Jiancheng Wang

2014-01-01

Full Text Available A series of manganese salts (Mn(NO32, MnCl2, MnSO4, and Mn(Ac2 and silicon materials (silica sand, silica sol, and tetraethyl orthosilicate were used to synthesize Mn/Si complexes in supercritical water using a tube reactor. X-ray diffraction (XRD, X-ray photoelectron spectrometer (XPS, transmission electron microscopy (TEM, and scanning electron microscopy (SEM were employed to characterize the structure and morphology of the solid products. It was found that MnO2, Mn2O3, and Mn2SiO4 could be obtained in supercritical water at 673 K in 5 minutes. The roles of both anions of manganese salts and silicon species in the formation of manganese silicon complexes were discussed. The inorganic manganese salt with the oxyacid radical could be easily decomposed to produce MnO2/SiO2 and Mn2O3/SiO2. It is interesting to found that Mn(Ac2 can react with various types of silicon to produce Mn2SiO4. The hydroxyl groups of the SiO2 surface from different silicon sources enhance the reactivity of SiO2.

Manganese oxide/graphene oxide composites for high-energyaqueous asymmetric electrochemical capacitors

CSIR Research Space (South Africa)

Jafta, CJ

2013-11-01

Full Text Available A high-energy aqueous asymmetric electrochemical capacitor was developed using manganese diox-ide ( -MnO2)/graphene oxide (GO) nanocomposites. The nanostructured -MnO2was prepared frommicron-sized commercial electrolytic manganese dioxide (EMD) via...

Sequential analysis: manganese, catecholamines, and L-dopa induced dyskinesia. [Cat's brain

Energy Technology Data Exchange (ETDEWEB)

Papavasiliou, P S; Miller, S T; Cotzias, G C; Kraner, H W; Hsieh, R S

1975-01-01

The paper specifies methodology for the sequential determination of manganese and catecholamines in selfsame brain samples and shows correlations between them. Small samples were obtained from five regions of brain of cats that had received either saline or levodopa. The doses of levodopa were varied so that although all animals reacted, some developed dyskinesia while others did not. Each sample was first analyzed nondestructively for manganese and then destructively for dopa and dopamine; thus errors inherent in analyzing separate samples, due to the structural heterogeneity of the brain, were avoided. Statistically significant correlations were found (1) between levodopa-induced dyskinesia and the concentrations of dopamine and manganese in some of the regions analysed, and (2) between the concentrations of dopamine and of manganese in the caudates of the cats receiving the highest doses of levodopa. (auth)

Dissolution of manganese and cobalt and their deposition on Type 304 stainless steel in liquid sodium

International Nuclear Information System (INIS)

Yokota, Norikatsu; Shimoyashiki, Shigehiro

1989-01-01

Dissolution of manganese and cobalt and their deposition on Type 304 stainless steel in liquid sodium at 833 K for 3.6 x 10 3 ks were examined using a liquid sodium pot. Manganese was easily dissolved in sodium from the iron-manganese alloy specimen and deposited on the steel to form two kind of deposition particles, α-phase (body-centered cubic) composed of iron and γ-phase (face-centered cubic) composed of iron and manganese, respectively. Cobalt which was less easily dissolved than manganese also deposited on the Type 304 stainless steel, giving an iron-cobalt alloy. These three deposition particles corresponded to the precipitation lines of iron-manganese and iron-cobalt phase diagrams at 833 K, respectively. Therefore, the deposition process of manganese or cobalt in sodium was explained as a precipitation process of iron-manganese or iron-cobalt in the solid region of the binary phase diagram. A sodium chromite (NaCrO 2 ) layer was formed on the steel surface. (author)

[Factors affecting biological removal of iron and manganese in groundwater].

Science.gov (United States)

Xue, Gang; He, Sheng-Bing; Wang, Xin-Ze

2006-01-01

Factors affecting biological process for removing iron and manganese in groundwater were analyzed. When DO and pH in groundwater after aeration were 7.0 - 7.5 mg/L and 6.8 - 7.0 respectively, not only can the activation of Mn2+ oxidizing bacteria be maintained, but also the demand of iron and manganese removal can be satisfied. A novel inoculating approach of grafting mature filter material into filter bed, which is easier to handle than selective culture media, was employed in this research. However, this approach was only suitable to the filter material of high-quality manganese sand with strong Mn2+ adsorption capacity. For the filter material of quartz sand with weak adsorption capacity, only culturing and domesticating Mn2+ oxidizing bacteria by selective culture media can be adopted as inoculation in filter bed. The optimal backwashing rate of biological filter bed filled with manganese sand and quartz sand should be kept at a relatively low level of 6 - 9 L/(m2 x s) and 7 -11 L/( m2 x s), respectively. Then the stability of microbial phase in filter bed was not disturbed, and iron and manganese removal efficiency recovered in less than 5h. Moreover, by using filter material with uniform particle size of 1.0 - 1.2 mm in filter bed, the filtration cycle reached as long as 35 - 38h.

Kinetics of manganese in MAG/MIG welding with a 18/8/6 wire

OpenAIRE

Tušek, Janez

2001-01-01

The paper deals with a study of MAG/MIG welding of low-alloy ferritic steel and highalloy austenitic steel with a 18/8/6 wire. Manganese burn-off from the wire in welding a single-V butt weld was studied. It was found that manganese burns off in the arc during melting of a droplet at the wire end, and from the weld pool during weld formation. The range of manganese burn-off depends mainly on the type of shielding gas used and the arc length, i.e., from the arc voltage. The manganese burn-off ...

Iron-responsive olfactory uptake of manganese improves motor function deficits associated with iron deficiency.

Directory of Open Access Journals (Sweden)

Jonghan Kim

Full Text Available Iron-responsive manganese uptake is increased in iron-deficient rats, suggesting that toxicity related to manganese exposure could be modified by iron status. To explore possible interactions, the distribution of intranasally-instilled manganese in control and iron-deficient rat brain was characterized by quantitative image analysis using T1-weighted magnetic resonance imaging (MRI. Manganese accumulation in the brain of iron-deficient rats was doubled after intranasal administration of MnCl(2 for 1- or 3-week. Enhanced manganese level was observed in specific brain regions of iron-deficient rats, including the striatum, hippocampus, and prefrontal cortex. Iron-deficient rats spent reduced time on a standard accelerating rotarod bar before falling and with lower peak speed compared to controls; unexpectedly, these measures of motor function significantly improved in iron-deficient rats intranasally-instilled with MnCl(2. Although tissue dopamine concentrations were similar in the striatum, dopamine transporter (DAT and dopamine receptor D(1 (D1R levels were reduced and dopamine receptor D(2 (D2R levels were increased in manganese-instilled rats, suggesting that manganese-induced changes in post-synaptic dopaminergic signaling contribute to the compensatory effect. Enhanced olfactory manganese uptake during iron deficiency appears to be a programmed "rescue response" with beneficial influence on motor impairment due to low iron status.

Neutron-activation analysis for investigation of biochemical manganese in soils cotton soweol zone of Uzbekistan

International Nuclear Information System (INIS)

Zhumamuratov, A.; Tillaev, T.; Khatamov, Sh.; Suvanov, M.; Osinskaya, N.S.; Rakhmanova, T.P.

2004-01-01

Full text: For many years we neutron activation analysis of soils sampled from different areas of landscape-geochemical regions of Uzbekistan including zone of extreme ecological catastrophe of Aral. Content of manganese and some other elements in the 'soil-cotton' system was investigated. Neutron-activation method of manganese determining with productivity up to 400 samples on shift with detection limit of 1,1 10 -5 % and discrepancies not more than 10%. Was developed extremely uniform distribution of manganese in cotton sowed soils of the Republic (340-1800mg/kg) is determined. Practically all soils of cotton-sowed zone of Republic are with lack of manganese. Distribution of manganese on soil profile of separate organs of cotton (leaves seeds etc.) was studied. Correlation between gross concentration of manganese and its active part extracted by distilled water on the basis of quantity analysis was found. Successive comparison of gross content of manganese in the soil with crop capacity of cotton in different zones of Republic made it possible to find interconnection between these quantities, which proves necessity of using micro-additions of manganese in the soils where its low concentration is detected

Sinterization of manganese ore tailings under argon atmosphere

Energy Technology Data Exchange (ETDEWEB)

Valduga, M.M.F.; Lima, F.; Lima, R.M.F. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

2014-07-01

Manganese is an element widely used in Metallurgy, however the Brazilian reserves has low grade. The aim of this work was to obtain and characterize the sinters from manganese ore tailings. The fines (less than 400⧣) were calcinated (800°C - 3600s) and homogenized with activated charcoal (7 and 10%) and CaO (5 and 10%). The sintering were carried out at 1135, 1140 and 1145°C during 7200 and 14400s under argon atmosphere. The sintered products were characterized by EDS analysis, BET surface area, apparent density, X-rays diffraction and SEM/EDS. The surface area was 0.03m2/g. The alkali element present (potassium) justified the low melting point of waste (1140°C). Due to the chemical complexity of the tailings, several phases were characterized in the products: pores, silicates with high content of manganese in the matrix, other silicates with different proportions of Al, Mn, Mg and Ca, pure Fe, SiO2, etc. (author)

Sinterization of manganese ore tailings under natural air

Energy Technology Data Exchange (ETDEWEB)

Lima, M.M.F.; Souza, L.G.P.R.M.F. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

2014-07-01

The manganese ore has wide application in metallurgy. However, from each of three hundred concentrations found, only one can be seen as a deposit. The aim of this study was to obtain and characterize a sinter from manganese ore tailing. The tailing was milled, classified (<400 ⧣) and calcinated (800°C - 3600s). The mixture had 12% moisture, 7 and 9% of activated charcoal. After homogenization, the sintering were carried out at 1140, 1145 and 1150°C during 1800, 7200 and 14400s at natural air. The sintered products were characterized by EDS analysis, BET surface area, apparent density, X-rays diffraction and SEM/EDS. The mass loss was approximately 14% and 16% in the calcination and sintering, respectively, due to the elimination of volatile products and water. The main phases characterized: SiO2, silicate with high content of manganese in the matrix and other silicates with different proportions of Ti, Na, Mn, Mg and Ca. (author)

Arsenic removal by manganese greensand filters

Energy Technology Data Exchange (ETDEWEB)

Phommavong, T. [Saskatchewan Environment, Regina (Canada); Viraraghavan, T. [Univ. of Regina, Saskatchewan (Canada). Faculty of Engineering

1994-12-31

Some of the small communities in Saskatchewan are expected to have difficulty complying with the new maximum acceptable concentration (MAC) of 25 {micro}g/L for arsenic. A test column was set up in the laboratory to study the removal of arsenic from the potable water using oxidation with KMnO{sub 4}, followed by manganese greensand filtration. Tests were run using water from the tap having a background arsenic concentration of <0.5 {micro}g/L and iron concentration in the range of 0.02 to 0.77 mg/L. The test water was spiked with arsenic and iron. Results showed that 61 % to 98% of arsenic can be removed from the potable water by oxidation with KMnO{sub 4} followed by manganese greensand filtration.

Arsenic enrichment in estuarine sediments-impact of iron and manganese mining

Digital Repository Service at National Institute of Oceanography (India)

Nair, M.; Joseph, T.; Balachandran, K.K.; Nair, K.K.C.; Paimpillii, J.S.

River Mandovi and Zuari, Goa (west coast of India) are flowing through iron and manganese mining areas and are heavily used for iron and manganese ore transport. This region generates 25-30 million tons of mining rejects per year. The iron ore...

Removal of iron and manganese using biological roughing up flow filtration technology.

Science.gov (United States)

Pacini, Virginia Alejandra; María Ingallinella, Ana; Sanguinetti, Graciela

2005-11-01

The removal of iron and manganese from groundwater using biological treatment methods is almost unknown in Latin America. Biological systems used in Europe are based on the process of double rapid biofiltration during which dissolved oxygen and pH need to be strictly controlled in order to limit abiotic iron oxidation. The performance of roughing filter technology in a biological treatment process for the removal of iron and manganese, without the use of chemical agents and under natural pH conditions was studied. Two pilot plants, using two different natural groundwaters, were operated with the following treatment line: aeration, up flow roughing filtration and final filtration (either slow or rapid). Iron and manganese removal efficiencies were found to be between 85% and 95%. The high solid retention capability of the roughing filter means that it is possible to remove iron and manganese simultaneously by biotic and abiotic mechanisms. This system combines simple, low-cost operation and maintenance with high iron and manganese removal efficiencies, thus constituting a technology which is particularly suited to small waterworks.

Research on the removal of radium from uranium effluent by air-aeration hydrated manganese hydroxide adsorption

International Nuclear Information System (INIS)

Zhang Jianguo; Chen Shaoqing; Qi Jing

2002-01-01

In the acidic leaching uranium process, pyrolusite or manganese oxide (MnO 2 ) powder is often used as an oxidizer. In the processed effluent, manganese ion present as a contaminant in addition to U, Ra, Th, As, Zn, Cu, F, SO 4 2- , etc. Manganese ion content is about 100∼200 mg/1 in effluent. In this case, a new process technique can be developed to treat the effluent using the Mn 2+ present in the effluent. The approach is as follows: The effluent is neutralized by lime milk to pH about 11. As a result, most contaminants are precipitated to meet the uranium effluent discharge standards (U, Th, Mn, SO 4 2- etc.), but radium is still present in the effluent. In this process, manganese ion forms manganese hydroxide Mn(OH) 2 . The manganese hydroxide is easily to oxide to form MnO(OH) 2 by air aeration. This hydrated manganese hydroxide complex can then be used to adsorb radium in effluent. The experiments show: (1) Effluent pH, manganese concentration in effluent, and aeration strength and time etc. influence the radium removal efficiency. Under the test conditions, when manganese in effluent is between 100∼300 mg/l, and pH is over 10.5, radium can be reduced to lower 1.11 Bq/1 in the processed effluent. Higher contents of impurity elements such as aluminum, silicon and magnesium in the effluent affect the removal efficiency; (2) Under the experimental conditions, the lime precipitation air-aeration formed hydrated manganese hydroxide complex sludge is stable. There is no obvious release of radium from the adsorbed hydrated manganese hydroxide complex sludge; (3) The current experiments show that hydrated manganese hydroxide complex sludge has a very good re-adsorption ability for removal of radium from uranium effluent. Some experimental parameters have been measured. (author)

Sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides

Directory of Open Access Journals (Sweden)

R.V. Smotraiev

2016-05-01

Full Text Available The actual problem of water supply in the world and in Ukraine, in particular, is a high level of pollution in water resources and an insufficient level of drinking water purification. With industrial wastewater, a significant amount of pollutants falls into water bodies, including suspended particles, sulfates, iron compounds, heavy metals, etc. Aim: The aim of this work is to determine the impact of aluminum and manganese ions additives on surface and sorption properties of zirconium oxyhydroxide based sorbents during their production process. Materials and Methods: The sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides were prepared by sol-gel method during the hydrolysis of metal chlorides (zirconium oxychloride ZrOCl2, aluminum chloride AlCl3 and manganese chloride MnCl2 with carbamide. Results: The surface and sorption properties of sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides were investigated. X-ray amorphous structure and evolved hydroxyl-hydrate cover mainly characterize the obtained xerogels. The composite sorbents based on xerogels of zirconium oxyhydroxide doped with aluminum oxyhydroxide (aS = 537 m2/g and manganese oxyhydroxide (aS = 356 m2/g have more developed specific surface area than single-component xerogels of zirconium oxyhydroxide (aS = 236 m2/g and aluminum oxyhydroxide (aS = 327 m2/g. The sorbent based on the xerogel of zirconium and manganese oxyhydroxides have the maximum SO42--ions sorption capacity. It absorbs 1.5 times more SO42–-ions than the industrial anion exchanger AN-221. The sorbents based on xerogels of zirconium oxyhydroxide has the sorption capacity of Fe3+-ions that is 1.5…2 times greater than the capacity of the industrial cation exchanger KU-2-8. The Na+-ions absorption capacity is 1.47…1.56 mmol/g for each sorbent. Conclusions: Based on these data it can be concluded that the proposed method is effective for sorbents production based on

In vitro sensitivity testing of Cladobotryum mycophilum to carbendazim and prochloraz manganese

Directory of Open Access Journals (Sweden)

Alinesi Chakwiya

2015-11-01

Full Text Available Limited information of fungicide efficacy on cultivated mushrooms and resistance development potential is available. Minor crop industries in general have a smaller arsenal of protectants to rely on and the likelihood of resistance build-up is of greater concern. This study focused on Cladobotryum mycophilum's sensitivity to carbendazim and prochloraz manganese following recent reports on decreased efficacy of both fungicides. The median effective dose (ED50 values for carbendazim ranged between 0.02 mg/L and 4.31 mg/L with 60% of the South African isolates being moderately resistant. The highest resistance factor for carbendazim was 215. Prochloraz manganese ED50 values varied from 0.00001 mg/L to 0.55 mg/L. A significant difference in mean ED50 values for both fungicides tested was observed. Using cluster analysis, no discrimination of isolates previously exposed and unexposed to prochloraz manganese was observed. A wide range of differences in ED50 values indicated moderate resistance to carbendazim and high sensitivity to prochloraz manganese among isolates under investigation. Discriminant analysis indicated significant differences between clusters contributed by one or a few variables. This study provided evidence that prochloraz manganese remains highly fungitoxic to C. mycophilum. However, prochloraz manganese is to be used in a disease management strategy in combination with strict farm hygiene management strategies to retain product efficacy and ensure crop protection.

Cognitive dysfunction, MRI findings and manganese levels in alcoholics

Energy Technology Data Exchange (ETDEWEB)

Itoh, Tsutomu; Nakane, Yoshibumi [Nagasaki Univ. (Japan). School of Medicine; Takahashi, Katsurou; Shimanaga, Masaki [National Nagasaki Medical Center, Omura (Japan)

2002-12-01

Alcoholic patients have been known to have brain atrophy and cognitive dysfunction. However, recent studies have reported bilateral signal hyperintensities of the globus pallidus on T1-weighted magnetic resonance imaging (MRI) in liver failure, findings that are typically associated with manganese intoxication. The present study compared brain atrophy on T1-weighted MRI, signal intensity ratios of the globus pallidus on T1-weighted MRI, whole blood manganese levels, and Wechsler Adult Intelligence Scale-Revised (WAIS-R) IQ parameters between alcoholics with and without liver cirrhosis, to investigate cognitive dysfunction, MRI findings and manganese levels in alcoholics. Pallidal hyperintensity was visually identified in 80% of alcoholic patients with liver cirrhosis. In addition, a significant correlation was seen between pallidal signal intensity (P.S.I.) ratio and blood manganese level. However, no significant correlations were found between pallidal signal intensity ratio and any of the WAIS-R parameters. These findings suggest that no direct connection exists between cognitive dysfunction and pallidal hyperintensity in alcoholic patients with liver cirrhosis. We confirmed that brain MRI in alcoholics could detect pallidal signal hyperintensity, suggesting severe liver dysfunction. In addition to diagnosis, brain MRI is useful for therapeutic psychoeducation to alcoholic patients with liver cirrhosis, visualizing the severe liver dysfunction. (author)

Cognitive dysfunction, MRI findings and manganese levels in alcoholics

International Nuclear Information System (INIS)

Itoh, Tsutomu; Nakane, Yoshibumi

2002-01-01

Alcoholic patients have been known to have brain atrophy and cognitive dysfunction. However, recent studies have reported bilateral signal hyperintensities of the globus pallidus on T1-weighted magnetic resonance imaging (MRI) in liver failure, findings that are typically associated with manganese intoxication. The present study compared brain atrophy on T1-weighted MRI, signal intensity ratios of the globus pallidus on T1-weighted MRI, whole blood manganese levels, and Wechsler Adult Intelligence Scale-Revised (WAIS-R) IQ parameters between alcoholics with and without liver cirrhosis, to investigate cognitive dysfunction, MRI findings and manganese levels in alcoholics. Pallidal hyperintensity was visually identified in 80% of alcoholic patients with liver cirrhosis. In addition, a significant correlation was seen between pallidal signal intensity (P.S.I.) ratio and blood manganese level. However, no significant correlations were found between pallidal signal intensity ratio and any of the WAIS-R parameters. These findings suggest that no direct connection exists between cognitive dysfunction and pallidal hyperintensity in alcoholic patients with liver cirrhosis. We confirmed that brain MRI in alcoholics could detect pallidal signal hyperintensity, suggesting severe liver dysfunction. In addition to diagnosis, brain MRI is useful for therapeutic psychoeducation to alcoholic patients with liver cirrhosis, visualizing the severe liver dysfunction. (author)

Contribution of arginase to manganese metabolism of Aspergillus niger.

Science.gov (United States)

Keni, Sarita; Punekar, Narayan S

2016-02-01

Aspects of manganese metabolism during normal and acidogenic growth of Aspergillus niger were explored. Arginase from this fungus was a Mn[II]-enzyme. The contribution of the arginase protein towards A. niger manganese metabolism was investigated using arginase knockout (D-42) and arginase over-expressing (ΔXCA-29) strains of A. niger NCIM 565. The Mn[II] contents of various mycelial fractions were found in the order: D-42 strain niger mycelia harvested from acidogenic growth media contain substantially less Mn[II] as compared to those from normal growth media. Nevertheless, acidogenic mycelia harbor considerable Mn[II] levels and a functional arginase. Altered levels of mycelial arginase protein did not significantly influence citric acid production. The relevance of arginase to cellular Mn[II] pool and homeostasis was evaluated and the results suggest that arginase regulation could occur via manganese availability.

Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

Science.gov (United States)

Birkner, Nancy; Nayeri, Sara; Pashaei, Babak; Najafpour, Mohammad Mahdi; Casey, William H; Navrotsky, Alexandra

2013-05-28

Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn(3+)/Mn(4+) ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.

Ternary manganese ferrite/graphene/polyaniline nanostructure with enhanced electrochemical capacitance performance

Science.gov (United States)

Xiong, Pan; Hu, Chenyao; Fan, Ye; Zhang, Wenyao; Zhu, Junwu; Wang, Xin

2014-11-01

A ternary manganese ferrite/graphene/polyaniline (MGP) nanostructure is designed and synthesized via a facile two-step approach. This nanostructure exhibits outstanding electrochemical performances, such as high specific capacitance (454.8 F g-1 at 0.2 A g-1), excellent rate capability (75.8% capacity retention at 5 A g-1), and good cycling stability (76.4% capacity retention after 5000 cycles at 2 A g-1), which are superior to those of its individual components (manganese ferrite, reduced-graphene oxide, polyaniline) and corresponding binary hybrids (manganese ferrite/graphene (MG), manganese ferrite/polyaniline (MP), and graphene/polyaniline (GP)). A symmetric supercapacitor device using the as-obtained hybrid has been fabricated and tested. The device exhibits a high specific capacitance of 307.2 F g-1 at 0.1 A g-1 with a maximum energy density of 13.5 W h kg-1. The high electrochemical performance of ternary MGP can be attributed to its well-designed nanostructure and the synergistic effect of the individual components.

Distribution of U and Th in Growth Zones of Manganese Nodules

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Friedrich, G. H. W.

1976-01-01

Growth zones and individual sublayers from one manganese nodule and three manganese crusts from an area south of Hawaii were analysed for U and Th by the delayed-neutron counting technique. The concentrations of uranium and thorium in the manganese nodule are highest in the outermost zone on top...... to the sediment which has low concentrations of Fe, relative to the zone last exposed to sea water, has also low U contents (2.7 ppm). Th concentrations are higher in the outermost zone on top of the nodule (40 to a maximum of 130 ppm) than in the zone last exposed to the sediment (about 20 ppm Th). Manganese...... crusts contain up to 9 ppm U in the outermost zones last exposed to the sea water. They also have higher concentrations of Th (up to 64 ppm) relative to the inner zones of the crust growing on altered andesitic rock, which contains about 8 ppm U and about 26 ppm Th as an average....

Chronic organic manganese administration in the rat does not damage dopaminergic nigrostriatal neurons.

Science.gov (United States)

Yong, V W; Perry, T L; Godolphin, W J; Jones, K A; Clavier, R M; Ito, M; Foulks, J G

1986-01-01

In an attempt to produce an animal model of Parkinson's disease, we injected rats repeatedly with high doses of methylcyclopentadienyl manganese tricarbonyl (MMT), a compound which has been reported to lower striatal dopamine content in mice. Chronic MMT administration for up to 5 months, even though it produced a substantial elevation in brain manganese content during the period of exposure, did not destroy dopaminergic nigrostriatal neurons. This was assessed by measurements of tyrosine hydroxylase activity and contents of dopamine and its metabolites in the striatum, and by histological examination of the substantia nigra. Our results differ from those of others who administered manganese chloride in drinking water to rats. This discrepancy is unlikely to be a consequence of differences in duration of exposure or route of administration. It could be due to our having used an organic rather than an inorganic manganese compound, or to a species difference in vulnerability to organic manganese between rats and mice.

Field-induced resistance switching at metal/perovskite manganese oxide interface

International Nuclear Information System (INIS)

Ohkubo, I.; Tsubouchi, K.; Harada, T.; Kumigashira, H.; Itaka, K.; Matsumoto, Y.; Ohnishi, T.; Lippmaa, M.; Koinuma, H.; Oshima, M.

2008-01-01

Planar type metal/insulator/metal structures composed of an epitaxial perovskite manganese oxide layer and various metal electrodes were prepared for electric-field-induced resistance switching. Only the electrode pairs including Al show good resistance switching and the switching ratio reaches its maximum of 1000. This resistance switching occurs around the interface between Al electrodes and epitaxial perovskite manganese oxide thin films

Subchronic, Low-Level Intraperitoneal Injections of Manganese (IV) Oxide and Manganese (II) Chloride Affect Rat Brain Neurochemistry

DEFF Research Database (Denmark)

Nielsen, Brian S.; Larsen, Erik Huusfeldt; Ladefoged, Ole

2017-01-01

Manganese (Mn) is neurotoxic and can induce manganism, a Parkinson-like disease categorized as being a serious central nervous system irreversible neurodegenerative disease. An increased risk of developing symptoms of Parkinson disease has been linked to work-related exposure, for example......Cl2)/kg bw/day for 7 d/wk for 8 or 12 weeks. This dosing regimen adds relevant new knowledge about Mn neurotoxicity as a consequence of low-dose subchronic Mn dosing. Manganese concentrations increased in the striatum, the rest of the brain, and in plasma, and regional brain neurotransmitter...... with MnCl2. Plasma prolactin concentration was not significantly affected due to a potentially reduced dopaminergic inhibition of the prolactin release from the anterior hypophysis. No effects on the striatal α-synuclein and synaptophysin protein levels were detected....

Electron-tunneling observation of local excited states in manganese-doped indium

International Nuclear Information System (INIS)

Tsang, J.; Ginsberg, D.M.

1980-01-01

We have measured the electron-tunneling characteristics of a dilute indium-manganese alloy. Well-defined structure was observed, corresponding to a band of local excited states within the energy gap. The measurements were made on two samples, and were quantitatively compared with the theory of Shiba and of Rusinov. We obtained good agreement of the tunneling data with the theory by taking into account only s-wave scattering of conduction electrons from the magnetic-impurity atoms. Even better agreement was obtained by including p- and d-wave scattering. Only by including these higher partial waves could we account for the magnitude of the observed depression of the transition temperature. The phase shifts used are in good agreement with band-theory values calculated recently

Kinetics of manganese in MAG/MIG welding with a 18/8/6 wire

International Nuclear Information System (INIS)

Tusek, J.

2001-01-01

The paper deals with a study of MAG/MIG welding of low-alloy ferritic steel and high-alloy austenitic steel with a 18/8/6 wire. Manganese burn-off from the wire in welding a single-V butt weld was studied. It was found that manganese burns off in the arc during melting of a droplet at the wire end, and from the weld pool during weld formation. The range of manganese burn-of-depends mainly on the type of shielding gas used and the arc length,i. e., from the arc voltage. The manganese burn-off increases with an increase of the content of active gases, i.e., CO 2 and O 2 in the neutral gas i. e., argon. It also increases with an increase in arc voltage. The longer the welding arc, the longer exposition of the filler materials to the welding arc and the wider the penetration, Which allows manganese vapours to evaporate from the weld pool. The most important finding is that manganese burn-off from the 18/8/6 wire during welding of austenitic stainless steel with low-alloy ferritic steel is considerably strong, i.e., from 20% to 30%; nevertheless the wire concerned is perfectly suitable for welding of different types of steel. (Author) 23 refs

10Be in manganese nodules

International Nuclear Information System (INIS)

Thomas, J.; Parker, P.; Mangini, A.; Cochran, K.; Turekian, K.; Krishnaswami, S.; Sharma, P.

1981-01-01

10 Be (t/sub 1/2) = 1.5 MY) is(formed in the upper atmosphere by cosmic ray spallation on nitrogen and oxygen. It is transported to the earth's surface via precipitation. In the oceans it is eventually associated with solid phases depositing on the ocean floor such as manganese nodules and deep-sea sediments. One of the assumptions that is normally made in analysis of such processes is that 10 Be has been produced at a relatively uniform rate over the pat several million years. If we assume, in addition, that the initial specific concentration of 10 Be as it precipitates with a solid phase is invariant with time, then we would expect that the decrease of the 10 Be concentration as a function of depth in a deep-sea core or in a manganese nodule would provide a record of sediment accumulation rate in the former and of growth rate in the latter. The possibility of using cosmic-ray produced 10 Be for the dating of marine deposits had been proposed 25 years ago by Arnold and Goel et al. The method of analysis used by these investigators, and those subsequently pursuing the problem, was low-level β counting. Though the potential of using 10 Be for dating manganese nodules was explored more than a decade ago, only a few measurements of 10 Be in nodules exist in date. This is largely because of the 10 Be measurements in environmental samples have gained considerable momentum during the past 3 to 4 years, after the development of accelerator mass spectrometry for its determination

Mercury distribution characteristics in primary manganese smelting plants.

Science.gov (United States)

Back, Seung-Ki; Sung, Jin-Ho; Moon, Young-Hoon; Kim, Young-Hee; Seok, Kwang-Seol; Song, Geum-Ju; Seo, Yong-Chil

2017-08-01

The mercury (Hg) distribution characteristics were investigated in three primary manganese smelting plants in Korea for the assessment of anthropogenic Hg released. Input and output materials were sampled from each process, and Hg concentrations in the samples were analyzed. Among the input materials, the most mercury was found in the manganese ore (83.1-99.7%) and mercury was mainly released through fly ash or off gas, depending on the condition of off gas cleaning system. As off gas temperature decreases, proportion and concentration of emitted gaseous elemental mercury (Hg 0 ) in off gas decreases. Based on mass balance study from these three plants and national manganese production data, the total amount of mercury released from those Korean plants was estimated to 644 kg/yr. About half of it was emitted into the air while the rest was released to waste as fly ash. With the results of this investigation, national inventory for Hg emission and release could be updated for the response to Minamata Convention on Mercury. Copyright © 2017. Published by Elsevier Ltd.

Iron and manganese removal from a groundwater supply

Energy Technology Data Exchange (ETDEWEB)

Lorenz, W.; Seifert, K.; Kasch, O.K. (Arber Richard P. Associates, Inc., Denver, CO (USA))

1988-11-01

The treatment options and planning techniques used by the town of Castle Rock (Colorado) for a new water treatment facility are described. Castle Rock officials assessed the available treatment options for dissolved iron and manganese removal and selected potassium permanganate as the primary oxidant to be followed by manganese greensand. A backup prechlorination system for oxidation was also installed. In addition, to prevent excess headloss buildup in the manganese greensand filter media, an anthracite carbon cap was used as the top filter medium for precipitate removal. It is recommended that a treatability study be performed to determine individual design criteria to allow for specific site conditions. The town also assessed the capital and operation and maintenance costs for both treatment at individual well fields and a centralized location for treatment of a cluster of well fields. The results indicate that it is more economical to provide centralized water treatment even though there are capital costs associated with piping raw water from the individual well fields to the central facility. 3 refs.

Defining the clinical course of multiple sclerosis

DEFF Research Database (Denmark)

Lublin, Fred D; Reingold, Stephen C; Cohen, Jeffrey A

2014-01-01

Accurate clinical course descriptions (phenotypes) of multiple sclerosis (MS) are important for communication, prognostication, design and recruitment of clinical trials, and treatment decision-making. Standardized descriptions published in 1996 based on a survey of international MS experts...

Dissection of the mechanism of manganese porphyrin-catalyzed chlorine dioxide generation.

Science.gov (United States)

Umile, Thomas P; Wang, Dong; Groves, John T

2011-10-17

Chlorine dioxide, an industrially important biocide and bleach, is produced rapidly and efficiently from chlorite ion in the presence of water-soluble, manganese porphyrins and porphyrazines at neutral pH under mild conditions. The electron-deficient manganese(III) tetra-(N,N-dimethyl)imidazolium porphyrin (MnTDMImP), tetra-(N,N-dimethyl)benzimidazolium (MnTDMBImP) porphyrin, and manganese(III) tetra-N-methyl-2,3-pyridinoporphyrazine (MnTM23PyPz) were found to be the most efficient catalysts for this process. The more typical manganese tetra-4-N-methylpyridiumporphyrin (Mn-4-TMPyP) was much less effective. Rates for the best catalysts were in the range of 0.24-32 TO/s with MnTM23PyPz being the fastest. The kinetics of reactions of the various ClO(x) species (e.g., chlorite ion, hypochlorous acid, and chlorine dioxide) with authentic oxomanganese(IV) and dioxomanganese(V)MnTDMImP intermediates were studied by stopped-flow spectroscopy. Rate-limiting oxidation of the manganese(III) catalyst by chlorite ion via oxygen atom transfer is proposed to afford a trans-dioxomanganese(V) intermediate. Both trans-dioxomanganese(V)TDMImP and oxoaqua-manganese(IV)TDMImP oxidize chlorite ion by 1-electron, generating the product chlorine dioxide with bimolecular rate constants of 6.30 × 10(3) M(-1) s(-1) and 3.13 × 10(3) M(-1) s(-1), respectively, at pH 6.8. Chlorine dioxide was able to oxidize manganese(III)TDMImP to oxomanganese(IV) at a similar rate, establishing a redox steady-state equilibrium under turnover conditions. Hypochlorous acid (HOCl) produced during turnover was found to rapidly and reversibly react with manganese(III)TDMImP to give dioxoMn(V)TDMImP and chloride ion. The measured equilibrium constant for this reaction (K(eq) = 2.2 at pH 5.1) afforded a value for the oxoMn(V)/Mn(III) redox couple under catalytic conditions (E' = 1.35 V vs NHE). In subsequent processes, chlorine dioxide reacts with both oxomanganese(V) and oxomanganese(IV)TDMImP to afford chlorate

Bioleaching of a manganese and silver Ore

International Nuclear Information System (INIS)

Porro, S.; Tedesco, P.H.; La Plata

1990-01-01

The bioleaching with a strain of Thiobacillus thiooxidans of the ore of Farallon Negro (Catamarca, Argentina) was studied in order to estimate its application to the solution and recovery of the manganese, and to improve the silver extraction. The State company which works the mine has not yet found an economical process to extract the manganese and has only reached a 30% efficiency in the recovery of silver by cianuration. The effects of pulp density variations and the addition of different quantities of FeS were analysed looking for the best working conditions. 74 μm (mesh Tyler 200) of ore particles were used because that is the size used in this plant for the cianuration process. (Author)

Oxidative Precipitation of Manganese from Acid Mine Drainage by Potassium Permanganate

Directory of Open Access Journals (Sweden)

Regeane M. Freitas

2013-01-01

Full Text Available Although oxidative precipitation by potassium permanganate is a widely recognised process for manganese removal, research dealing with highly contaminated acid mine drainage (AMD has yet to be performed. The present study investigated the efficiency of KMnO4 in removing manganese from AMD effluents. Samples of AMD that originated from inactive uranium mine in Brazil were chemically characterised and treated by KMnO4 at pH 3.0, 5.0, and 7.0. Analyses by Raman spectroscopy and geochemical modelling using PHREEQC code were employed to assess solid phases. Results indicated that the manganese was rapidly oxidised by KMnO4 in a process enhanced at higher pH. The greatest removal, that is, 99%, occurred at pH 7.0, when treated waters presented manganese levels as low as 1.0 mg/L, the limit established by the Brazilian legislation. Birnessite (MnO2, hausmannite (Mn3O4, and manganite (MnOOH were detected by Raman spectroscopy. These phases were consistently identified by the geochemical model, which also predicted phases containing iron, uranium, manganese, and aluminium during the correction of the pH as well as bixbyite (Mn2O3, nsutite (MnO2, pyrolusite (MnO2, and fluorite (CaF2 following the KMnO4 addition.

Manganese deposition in drinking water distribution systems.

Science.gov (United States)

Gerke, Tammie L; Little, Brenda J; Barry Maynard, J

2016-01-15

This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400 μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn(3+) and Mn(4+)) and hollandite (Mn(2+) and Mn(4+)), and a Mn silicate, braunite (Mn(2+) and Mn(4+)), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality. Copyright © 2015 Elsevier B.V. All rights reserved.

Manganese and the II system in photosynthesis

International Nuclear Information System (INIS)

Joyard, Jacques

1971-01-01

The evolution during greening of some components of system II of photosynthesis has been followed in plastids extracted from Zea mays grown in the dark. Manganese studies were done by means of neutron activation, electron spin resonance (ESR) was also used in some experiments. Oxygen evolution of isolated plastids was followed by polarography (with a membrane electrode). The evolution of manganese/carotenoids ratio can be divided in three parts. During the first hour of greening, the increase shows an input of Mn in the plastids; then, whereas carotenoids content of those plastids presents no changes, Mn is released in the medium; at last, carotenoids synthesis is parallel to Mn fixation in the plastids, the ratio being constant after 24 hours of greening. From various measurements on chloroplastic manganese, it is shown that the development of system II can be divided in two main phases: during the first one (that is during the first day of light) the components are not yet bound together but the relations become more and more strong. Then, during the last period of the development, the organisation of system II is complete and the transformations of the plastids are parallel to the raise of their activity. (author) [fr

Determination of the oxidizing capacity of manganese ores.

Science.gov (United States)

Prasad, R

1974-09-01

An accurate method is described for determining the amount of active oxygen in manganese ores, based on the oxidation-reduction reaction between the ore and arsenic(III) in presence of ammonium molybdate, followed by the back-titration of excess of arsenic(III) with cerium(IV), using osmium tetroxide as catalyst and Disulphine Blue V as indicator. A survey has been made of the applicability of this method to various pyrolusite ores containing less than 0.2% phosphorus. Aluminium(III), copper(II), iron(III), manganese(II), and molybdenum(VI) do not interfere. Up to 30% phosphorus(V) causes no interference.

Manganese Oxidation by Bacteria: Biogeochemical Aspects

Digital Repository Service at National Institute of Oceanography (India)

Sujith, P.P.; LokaBharathi, P.A.

Manganese is an essential trace metal that is not as readily oxidizable like iron. Several bacterial groups posses the ability to oxidize Mn effectively competing with chemical oxidation. The oxides of Mn are the strongest of the oxidants, next...

21 CFR 73.2775 - Manganese violet.

Science.gov (United States)

2010-04-01

.... Mercury (as Hg), not more than 1 part per million. Total color, based on Mn content in “as is” sample, not less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics...

Iron Intermetallic Phases in the Alloy Based on Al-Si-Mg by Applying Manganese

Directory of Open Access Journals (Sweden)

Podprocká R.

2017-09-01

Full Text Available Manganese is an effective element used for the modification of needle intermetallic phases in Al-Si alloy. These particles seriously degrade mechanical characteristics of the alloy and promote the formation of porosity. By adding manganese the particles are being excluded in more compact shape of “Chinese script” or skeletal form, which are less initiative to cracks as Al5FeSi phase. In the present article, AlSi7Mg0.3 aluminium foundry alloy with several manganese content were studied. The alloy was controlled pollution for achieve higher iron content (about 0.7 wt. % Fe. The manganese were added in amount of 0.2 wt. %, 0.6 wt. %, 1.0 wt. % and 1.4 wt. %. The influence of the alloying element on the process of crystallization of intermetallic phases were compared to microstructural observations. The results indicate that increasing manganese content (> 0.2 wt. % Mn lead to increase the temperature of solidification iron rich phase (TAl5FeSi and reduction this particles. The temperature of nucleation Al-Si eutectic increase with higher manganese content also. At adding 1.4 wt. % Mn grain refinement and skeleton particles were observed.

Uniform manganese hexacyanoferrate hydrate nanocubes featuring superior performance for low-cost supercapacitors and nonenzymatic electrochemical sensors

Science.gov (United States)

Pang, Huan; Zhang, Yizhou; Cheng, Tao; Lai, Wen-Yong; Huang, Wei

2015-09-01

Uniform manganese hexacyanoferrate hydrate nanocubes are prepared via a simple chemical precipitation method at room temperature. Due to both micro/mesopores of the Prussian blue analogue and nanocubic structures, the manganese hexacyanoferrate hydrate nanocubes allow the efficient charge transfer and mass transport for electrolyte solution and chemical species. Thus, the manganese hexacyanoferrate hydrate nanocube electrode shows a good rate capability and cycling stability for electrochemical capacitors. Furthermore, electrodes modified with manganese hexacyanoferrate hydrate nanocubes demonstrate a sensitive electrochemical response to hydrogen peroxide (H2O2) in buffer solutions with a high selectivity.Uniform manganese hexacyanoferrate hydrate nanocubes are prepared via a simple chemical precipitation method at room temperature. Due to both micro/mesopores of the Prussian blue analogue and nanocubic structures, the manganese hexacyanoferrate hydrate nanocubes allow the efficient charge transfer and mass transport for electrolyte solution and chemical species. Thus, the manganese hexacyanoferrate hydrate nanocube electrode shows a good rate capability and cycling stability for electrochemical capacitors. Furthermore, electrodes modified with manganese hexacyanoferrate hydrate nanocubes demonstrate a sensitive electrochemical response to hydrogen peroxide (H2O2) in buffer solutions with a high selectivity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04322k

Manganese toxicity effects on nodulation and nitrogen fixation of beans (Phaseolus vulgaris L. ), in acid soils

Energy Technology Data Exchange (ETDEWEB)

Doebereiner, J

1966-02-01

Three greenhouse experiments were conducted to study manganese toxicity effects on the nitrogen fixing symbiosis of beans (Phaseolus vulgaris). Addition of 40 ppm of manganese to two acid soils affected nodulation and nitrogen fixation. Dependent on the Rhizobion strain either nodule numbers or efficiency in nitrogen fixation were reduced; the efficiency of one Rhizobium-host combination was more affected than another. Under less severe conditions of manganese toxicity, reduction of nodule numbers or of efficiency in nitrogen fixation could be compensated by an increase of nodule size. In the absence of manganese toxicity nodulation and nitrogen fixation of beans were abundant in a soil with pH 4.4. Naturally occurring manganese toxicity in a gray hydromorphic soil was eliminated by liming. The total nitrogen content of bean plants which were dependent on symbiotic nitrogen fixation decreased linearly with the logarithm of the manganese concentration in the plants. This did not happen when the plants were grown with mineral nitrogen. The role of manganese toxicity in the well known sensitivity to acid soil conditions of certain legumes and the importance of selection of manganese tolerant Rhizobium strains for the inoculation of beans in acid tropical soils, are discussed. 25 references, 1 figure, 6 tables.

Hydrothermal manganese oxide deposits from the Izu-Ogasawara (Bonin)-Mariana Arc and adjacent areas

Energy Technology Data Exchange (ETDEWEB)

Usui, A.; Nishimura, A. (Geological Survey of Japan, Tsukuba (Japan))

1992-04-27

Modern and fossil hydrothermal manganese oxide deposits were discovered from a number of locations in the Izu-Ogasawara(Bonin)-Mariana Arc and adjacent areas during the Hakurei-Maru cruises from 1984 to 1989. This paper describes the occurrence and characteristics of these manganese deposits and their geological significance. It was found that the mineralogical and chemical composition and microstructure of the deposits are typically different from manganese nodules and crusts of hydrogenetic or diagenetic origin. Hardpans, veinlets, sheets, and irregular mass of the hydrothermal manganese deposits often cover a large area of sea bed, which suggests possible high-temperature hydrothermal sulfide deposits in their vicinity. On the other hand, the manganese minerals sometimes occur as substrate of younger hydrogenetic crusts and as nucleus of hydrogenetic nodules, which can provide a geological history of low-temperature hydrothermal activity on the past island arcs. 45 refs., 19 figs., 3 tabs.

Manganese and Iron Catalysts in Alkyd Paints and Coatings

Directory of Open Access Journals (Sweden)

Ronald Hage

2016-04-01

Full Text Available Many paint, ink and coating formulations contain alkyd-based resins which cure via autoxidation mechanisms. Whilst cobalt-soaps have been used for many decades, there is a continuing and accelerating desire by paint companies to develop alternatives for the cobalt soaps, due to likely classification as carcinogens under the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals legislation. Alternative driers, for example manganese and iron soaps, have been applied for this purpose. However, relatively poor curing capabilities make it necessary to increase the level of metal salts to such a level that often coloring of the paint formulation occurs. More recent developments include the application of manganese and iron complexes with a variety of organic ligands. This review will discuss the chemistry of alkyd resin curing, the applications and reactions of cobalt-soaps as curing agents, and, subsequently, the paint drying aspects and mechanisms of (model alkyd curing using manganese and iron catalysts.

A redox-assisted supramolecular assembly of manganese oxide nanotube

International Nuclear Information System (INIS)

Tao Li; Sun Chenggao; Fan Meilian; Huang Caijuan; Wu Hailong; Chao Zisheng; Zhai Hesheng

2006-01-01

In this paper, we report the hydrothermal synthesis of manganese oxide nanotube from an aqueous medium of pH 7, using KMnO 4 and MnCl 2 as inorganic precursors, polyoxyethylene (10) nonyl phenyl ether (TX-10) a surfactant and acetaldehyde an additive. The characterization of X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and N 2 adsorption at 77 K (BET) reveals that the synthesized manganese oxide nanotube has a mesopore size of ca. 3.65 nm and a wall thickness of ca. 12 nm, with the wall being composed of microporous crystals of monoclinic manganite. The X-ray photoelectron spectroscopy (XPS) result demonstrates a decrease of the binding energy of the Mn 3+ in the manganese oxide nanotube, which may be related to both the nanotubular morphology and the crystalline pore wall. A mechanism of a redox-assisted supramolecular assembly, regulated by acetaldehyde, is postulated

Dimensional crossover in manganese based analogues of iron pnictides

Energy Technology Data Exchange (ETDEWEB)

Zingl, Manuel; Assmann, Elias; Aichhorn, Markus [University of Technology, Institute of Theoretical Physics and Computational Physics, Graz (Austria)

2016-07-01

The manganese pnicitides BaMn{sub 2}As{sub 2} and LaOMnAs crystallize in the same structure as the extensively studied iron pnictide high-temperature superconductors BaFe{sub 2}As{sub 2} and LaOFeAs. In contrast to the d{sup 6} configuration of the iron systems, the manganese d-shell is only half-filled (d{sup 5}). As a consequence, electronic correlations are much stronger, placing these compounds at the verge of the Mott metal-insulator transition. In this region of the phase diagram materials are prone to enhanced magnetism, apparent in the remarkably high Neel temperature of 625 K for BaMn{sub 2}As{sub 2}. We demonstrate that the experimentally observed differences in the Neel temperatures, the band gap, and the optical properties of the manganese compounds under consideration can be traced back to their effective dimensionality. Our fully charge self-consistent DFT+DMFT calculations show excellent agreement with experiments, especially measured optical spectra.

Cyclic deformation and fatigue behaviors of Hadfield manganese steel

Energy Technology Data Exchange (ETDEWEB)

Kang, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, F.C., E-mail: zfc@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Long, X.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Lv, B. [School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China)

2014-01-03

The cyclic deformation characteristics and fatigue behaviors of Hadfield manganese steel have been investigated by means of its ability to memorize strain and stress history. Detailed studies were performed on the strain-controlled low cycle fatigue (LCF) and stress-controlled high cycle fatigue (HCF). Initial cyclic hardening to saturation or peak stress followed by softening to fracture occurred in LCF. Internal stress made the dominant contribution to the fatigue crack propagation until failure. Effective stress evolution revealed the existence of C–Mn clusters with short-range ordering in Hadfield manganese steel and demonstrated that the interaction between C atoms in the C–Mn cluster and dislocation was essential for its cyclic hardening. The developing/developed dislocation cells and stacking faults were the main cyclic deformation microstructures on the fractured sample surface in LCF and HCF, which manifested that fatigue failure behavior of Hadfield manganese steel was induced by plastic deformation during strain-controlled or stress-controlled testing.

Study and optimisation of manganese oxide-based electrodes for electrochemical supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Staiti, P.; Lufrano, F. [CNR-ITAE, Istituto di Tecnologie Avanzate per l' Energia ' ' Nicola Giordano' ' , Via Salita S. Lucia n. 5, 98126 S. Lucia, Messina (Italy)

2009-02-01

A manganese oxide material was synthesised by an easy precipitation method based on reduction of potassium permanganate(VII) with a manganese(II) salt. The material was treated at different temperatures to study the effect of thermal treatment on capacitive property. The best capacitive performance was obtained with the material treated at 200 C. This material was used to prepare electrodes with different amounts of polymer binder, carbon black and graphite fibres to individuate the optimal composition that gave the best electrochemical performances. It was found that graphite fibres improve the electrochemical performance of electrodes. The highest specific capacitance (267 F g{sup -1} MnO{sub x}) was obtained with an electrode containing 70% of MnO{sub x}, 15% of carbon black, 10% of graphite fibres and 5% of PVDF. This electrode, with CB/GF ratio of 1.5, showed a higher utilization of manganese oxide. The results reported in the present paper further confirmed that manganese oxide is a very interesting material for supercapacitor application. (author)

Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source

International Nuclear Information System (INIS)

Cardoso, Antonio

1976-01-01

Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction 55 Mn (n.gamma) 56 Mn, high concentration of manganese in the matrix and short half - life of 56 Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions 56 Fe(n,p) 56 Mn and 59 Co (n, α) 56 were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

Electrochemical oxidation of sulfites by DWCNTs, MWCNTs, higher fullerenes and manganese

Science.gov (United States)

Uzun, Dzhamal; Pchelarov, George; Dimitrov, Ognian; Vassilev, Sasho; Obretenov, Willi; Petrov, Konstantin

2018-03-01

Different electrocatalysts were tested for oxidation of sulfites to sulfates, namely, manganese thin films deposited on fullerenes and carbon nanotubes. The results presented clearly show that electrodes containing HFs (higher fullerenes), DWCNTs (double-wall carbon nanotubes) and manganese acetate are effective catalysts in S/O2 fuel cells. HFs and DWCNTs have high catalytic activity and can be employed as standalone catalysts. Manganese was deposited on DWCNTs, HFs and fullerenes C60/C70 by a thermal process. The electrocatalysts were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical testing was carried out by plotting the E/V polarization curve. The polarization curves of the electrodes composed of pristine DWCNTs showed the lowest overpotentials.

Effect of mass density on surface morphology of electrodeposited manganese oxide films

Science.gov (United States)

Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder

2018-05-01

This work focus on high surface area morphology of manganese oxide films which are currently required for electrochemical capacitor electrode to enhance their performance. Electrodeposition of manganese oxide films was carried out using Chronoamperometry for different deposition time ranging from 30 to 120 sec. Cronoamperomertic I-T integrated data have been used to analyze active mass of all electrodeposited films. Morphological study of the deposited films with different mass was carried out through scanning electron microscopy. Film deposited for 30 sec time show highest porous morphology than others. Manganese oxide films with high porosity are suitable for electrochemical capacitor electrode.

The influence of high iron diet on rat lung manganese absorption

International Nuclear Information System (INIS)

Thompson, Khristy; Molina, Ramon; Donaghey, Thomas; Brain, Joseph D.; Wessling-Resnick, Marianne

2006-01-01

Individuals chronically exposed to manganese are at high risk for neurotoxic effects of this metal. A primary route of exposure is through respiration, although little is known about pulmonary uptake of metals or factors that modify this process. High dietary iron levels inversely affect intestinal uptake of manganese, and a major goal of this study was to determine if dietary iron loading could increase lung non-heme iron levels and alter manganese absorption. Rats were fed a high iron (1% carbonyl iron) or control diet for 4 weeks. Lung non-heme iron levels increased ∼2-fold in rats fed the high iron diet. To determine if iron-loading affected manganese uptake, 54 Mn was administered by intratracheal (it) instillation or intravenous (iv) injection for pharmacokinetic studies. 54 Mn absorption from the lungs to the blood was lower in it-instilled rats fed the 1% carbonyl iron diet. Pharmacokinetics of iv-injected 54 Mn revealed that the isotope was cleared more rapidly from the blood of iron-loaded rats. In situ analysis of divalent metal transporter-1 (DMT1) expression in lung detected mRNA in airway epithelium and bronchus-associated lymphatic tissue (BALT). Staining of the latter was significantly reduced in rats fed the high iron diet. In situ analysis of transferrin receptor (TfR) mRNA showed staining in BALT alone. These data demonstrate that manganese absorption from the lungs to the blood can be modified by iron status and the route of administration

Synthesis of condensed double cesium manganese phosphates in melts of polyphosphoric acids

International Nuclear Information System (INIS)

Guzeeva, L.S.; Tananaev, I.V.

1988-01-01

This work is a continuation of investigations to establish the composition and formation conditions of condensed double cesium manganese phosphates and obtain x-ray and other characteristics of the compounds isolated. We studied cross sections of Cs 2 O-MnO 2 -P 2 O 5 -H 2 O systems at 150-400 degree C and three initial P : Mn ratios - 5, 7.5, and 10 - and at a constant P : Mn ratio of 15. The reaction of manganese and cesium oxides with melts of polyphosphoric acids at 150-400 degree C leads to the separation of three types of trivalent manganese and cesium condensed double phosphates - Cs 2 MnH 3 (P 2 O 7 ) 2 , triphosphate CsMnHP 3 O 10 , and cyclohexaphosphate Cs 3 Mn 3 -(P 6 O 18 ) 2 - in addition to a divalent manganese double cyclotriphosphate CsMnP 3 O 9 . The compounds separated were characterized by chemical, x-ray phase analysis, IR spectroscopic, and thermogravimetric methods

Nanodiamond-Manganese dual mode MRI contrast agents for enhanced liver tumor detection.

Science.gov (United States)

Hou, Weixin; Toh, Tan Boon; Abdullah, Lissa Nurrul; Yvonne, Tay Wei Zheng; Lee, Kuan J; Guenther, Ilonka; Chow, Edward Kai-Hua

2017-04-01

Contrast agent-enhanced magnetic resonance (MR) imaging is critical for the diagnosis and monitoring of a number of diseases, including cancer. Certain clinical applications, including the detection of liver tumors, rely on both T1 and T2-weighted images even though contrast agent-enhanced MR imaging is not always reliable. Thus, there is a need for improved dual mode contrast agents with enhanced sensitivity. We report the development of a nanodiamond-manganese dual mode contrast agent that enhanced both T1 and T2-weighted MR imaging. Conjugation of manganese to nanodiamonds resulted in improved longitudinal and transverse relaxivity efficacy over unmodified MnCl 2 as well as clinical contrast agents. Following intravenous administration, nanodiamond-manganese complexes outperformed current clinical contrast agents in an orthotopic liver cancer mouse model while also reducing blood serum concentration of toxic free Mn 2+ ions. Thus, nanodiamond-manganese complexes may serve as more effective dual mode MRI contrast agent, particularly in cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Multiple Voices, Multiple Realities: Self-Defined Images of Self among Adolescent Hispanic English Language Learners

Science.gov (United States)

Ajayi, Lasisi J.

2006-01-01

Acquisition of multiple identities to negotiate new forms of social participation and the concomitant attendant multiple languages and multiple cultures is "sine qua non" to success in English language learning classrooms. This study therefore, investigates how middle school Hispanic students reconceptualize their identities to negotiate…

Noncollinear magnetism in manganese nanostructures

Czech Academy of Sciences Publication Activity Database

Zelený, Martin; Šob, Mojmír; Hafner, J.

2009-01-01

Roč. 80, č. 14 (2009), 144414/1-144414/19 ISSN 1098-0121 R&D Projects: GA AV ČR IAA100100920; GA MŠk OC09011 Institutional research plan: CEZ:AV0Z20410507 Keywords : magnetism of nanostructures * nanowires * noncollinear magnetism * manganese Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.475, year: 2009

Inverse association of intellectual function with very low blood lead but not with manganese exposure in Italian adolescents

Energy Technology Data Exchange (ETDEWEB)

Lucchini, Roberto G., E-mail: lucchini@med.unibs.it [Department of Preventive Medicine, Mount Sinai School of Medicine, NY (United States); Section of Occupational Medicine, University of Brescia, P.le Spedali Civili 1, 25123 Brescia (Italy); Zoni, Silvia [Section of Occupational Medicine, University of Brescia, P.le Spedali Civili 1, 25123 Brescia (Italy); Guazzetti, Stefano [Public Health Service, Reggio Emilia (Italy); Bontempi, Elza [INSTM and Chemistry for Technologies Laboratory, University of Brescia (Italy); Micheletti, Serena [Cognition Psychology Neuroscience lab., University of Pavia and Unit of Child Neurology and Psychiatry, Civil Hospital of Brescia (Italy); Broberg, Karin [Division of Occupational and Environmental Medicine, Lund University (Sweden); Parrinello, Giovanni [Statistics and Biometry, University of Brescia (Italy); Smith, Donald R. [Microbiology and Environmental Toxicology, University of California at Santa Cruz (United States)

2012-10-15

Background: Pediatric lead (Pb) exposure impacts cognitive function and behavior and co-exposure to manganese (Mn) may enhance neurotoxicity. Objectives: To assess cognitive and behavioral function in adolescents with environmental exposure to Pb and Mn. Methods: In this cross sectional study, cognitive function and behavior were examined in healthy adolescents with environmental exposure to metals. The Wechsler Intelligence Scale for Children (WISC) and the Conners-Wells' Adolescent Self-Report Scale Long Form (CASS:L) were used to assess cognitive and behavioral function, respectively. ALAD polymorphisms rs1800435 and rs1139488 were measured as potential modifiers. Results: We examined 299 adolescents (49.2% females) aged 11-14 years. Blood lead (BPb) averaged 1.71 {mu}g/dL (median 1.5, range 0.44-10.2), mean Blood Manganese (BMn) was 11.1 {mu}g/dL (median 10.9, range 4.00-24.1). Average total IQ was 106.3 (verbal IQ=102, performance IQ=109.3). According to a multiple regression model considering the effect of other covariates, a reduction of about 2.4 IQ points resulted from a two-fold increase of BPb. The Benchmark Level of BPb associated with a loss of 1 IQ-point (BML01) was 0.19 {mu}g/dL, with a lower 95% confidence limit (BMLL01) of 0.11 {mu}g/dL. A very weak correlation resulted between BPb and the ADHD-like behavior (Kendall's tau rank correlation=0.074, p=0.07). No influence of ALAD genotype was observed on any outcome. Manganese was not associated with cognitive and behavioral outcomes, nor was there any interaction with lead. Conclusions: These findings demonstrate that very low level of lead exposure has a significant negative impact on cognitive function in adolescent children. Being an essential micro-nutrient, manganese may not cause cognitive effects at these low exposure levels.

Inverse association of intellectual function with very low blood lead but not with manganese exposure in Italian adolescents

International Nuclear Information System (INIS)

Lucchini, Roberto G.; Zoni, Silvia; Guazzetti, Stefano; Bontempi, Elza; Micheletti, Serena; Broberg, Karin; Parrinello, Giovanni; Smith, Donald R.

2012-01-01

Background: Pediatric lead (Pb) exposure impacts cognitive function and behavior and co-exposure to manganese (Mn) may enhance neurotoxicity. Objectives: To assess cognitive and behavioral function in adolescents with environmental exposure to Pb and Mn. Methods: In this cross sectional study, cognitive function and behavior were examined in healthy adolescents with environmental exposure to metals. The Wechsler Intelligence Scale for Children (WISC) and the Conners-Wells’ Adolescent Self-Report Scale Long Form (CASS:L) were used to assess cognitive and behavioral function, respectively. ALAD polymorphisms rs1800435 and rs1139488 were measured as potential modifiers. Results: We examined 299 adolescents (49.2% females) aged 11–14 years. Blood lead (BPb) averaged 1.71 μg/dL (median 1.5, range 0.44–10.2), mean Blood Manganese (BMn) was 11.1 μg/dL (median 10.9, range 4.00–24.1). Average total IQ was 106.3 (verbal IQ=102, performance IQ=109.3). According to a multiple regression model considering the effect of other covariates, a reduction of about 2.4 IQ points resulted from a two-fold increase of BPb. The Benchmark Level of BPb associated with a loss of 1 IQ-point (BML01) was 0.19 μg/dL, with a lower 95% confidence limit (BMLL01) of 0.11 μg/dL. A very weak correlation resulted between BPb and the ADHD-like behavior (Kendall's tau rank correlation=0.074, p=0.07). No influence of ALAD genotype was observed on any outcome. Manganese was not associated with cognitive and behavioral outcomes, nor was there any interaction with lead. Conclusions: These findings demonstrate that very low level of lead exposure has a significant negative impact on cognitive function in adolescent children. Being an essential micro-nutrient, manganese may not cause cognitive effects at these low exposure levels.

Manganese-enhanced magnetic resonance imaging (MEMRI).

Science.gov (United States)

Koretsky, Alan P; Silva, Afonso C

2004-12-01

Manganese ion (Mn2+) is an essential metal that participates as a cofactor in a number of critical biological functions, such as electron transport, detoxification of free radicals and synthesis of neurotransmitters. Mn2+ can enter excitable cells using some of the same transport systems as Ca2+ and it can bind to a number of intracellular sites because it has high affinity for Ca2+ and Mg2+ binding sites on proteins and nucleic acids. Paramagnetic forms of manganese ions are potent MRI relaxation agents. Indeed, Mn2+ was the first contrast agent proposed for use in MRI. Recently, there has been renewed interest in combining the strong MRI relaxation effects of Mn2+ with its unique biology, in order to further expand the already broad assortment of useful information that can be measured by MRI. Such an approach has been continuously developed in the past several years to provide unique tissue contrast, to assess tissue viability, to act as a surrogate marker of calcium influx into cells and to trace neuronal connections. This special issue of NMR in Biomedicine on manganese-enhanced MRI (MEMRI) is aimed at providing the readers of this journal with an extensive review of some of the most prominent applications of MEMRI in biological systems. Written by several of the leaders in the field, the reviews and original research articles featured in this special issue are likely to offer an exciting and inspiring view of the broad range of applications of MEMRI. Copyright 2004 John Wiley & Sons, Ltd.

Associations of iron metabolism genes with blood manganese levels: a population-based study with validation data from animal models

Directory of Open Access Journals (Sweden)

Claus Henn Birgit

2011-11-01

Full Text Available Abstract Background Given mounting evidence for adverse effects from excess manganese exposure, it is critical to understand host factors, such as genetics, that affect manganese metabolism. Methods Archived blood samples, collected from 332 Mexican women at delivery, were analyzed for manganese. We evaluated associations of manganese with functional variants in three candidate iron metabolism genes: HFE [hemochromatosis], TF [transferrin], and ALAD [δ-aminolevulinic acid dehydratase]. We used a knockout mouse model to parallel our significant results as a novel method of validating the observed associations between genotype and blood manganese in our epidemiologic data. Results Percentage of participants carrying at least one copy of HFE C282Y, HFE H63D, TF P570S, and ALAD K59N variant alleles was 2.4%, 17.7%, 20.1%, and 6.4%, respectively. Percentage carrying at least one copy of either C282Y or H63D allele in HFE gene was 19.6%. Geometric mean (geometric standard deviation manganese concentrations were 17.0 (1.5 μg/l. Women with any HFE variant allele had 12% lower blood manganese concentrations than women with no variant alleles (β = -0.12 [95% CI = -0.23 to -0.01]. TF and ALAD variants were not significant predictors of blood manganese. In animal models, Hfe-/- mice displayed a significant reduction in blood manganese compared with Hfe+/+ mice, replicating the altered manganese metabolism found in our human research. Conclusions Our study suggests that genetic variants in iron metabolism genes may contribute to variability in manganese exposure by affecting manganese absorption, distribution, or excretion. Genetic background may be critical to consider in studies that rely on environmental manganese measurements.

Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks.

Science.gov (United States)

Shen, Yiwen; Hattink, Maarten H N; Samadi, Payman; Cheng, Qixiang; Hu, Ziyiz; Gazman, Alexander; Bergman, Keren

2018-04-16

Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. We present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly network testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 µs control plane latency for data-center and high performance computing platforms.

76 FR 47996 - Cobalt Lithium Manganese Nickel Oxide; Significant New Use Rule

Science.gov (United States)

2011-08-08

... Safety and Health Administration (OSHA) Permissible Exposure Level (PEL) of 0.1 mg/m\\3\\ for nickel. The... 2070-AB27 Cobalt Lithium Manganese Nickel Oxide; Significant New Use Rule AGENCY: Environmental... lithium manganese nickel oxide (CAS No. 182442-95-1), which was the subject of premanufacture notice (PMN...

Early diagenesis of manganese, iron and phosphorus in European continental margin sediments

NARCIS (Netherlands)

Zee, C. van der

2002-01-01

This thesis describes the results of a project that was carried out as a part of the Sedimentary Manganese and Iron cycLEs (SMILE) research program funded by the Netherlands Organisation of Scientific Research (NWO/ALW). SMILE aimed at studying the biogeochemistry of iron and manganese cycles in

Early diagenesis of Manganese, Iron and Phosphorus in European continental margin sediments

NARCIS (Netherlands)

van der Zee, C.

2002-01-01

This thesis describes the results of a project that was carried out as a part of the Sedimentary Manganese and Iron cycLEs (SMILE) research program funded by the Netherlands Organisation of Scientific Research (NWO/ALW). SMILE aimed at studying the biogeochemistry of iron and manganese cycles in

A regional mineralogical study of the manganese-bearing Voelwater subgroup in the northern Cape Province

International Nuclear Information System (INIS)

Kleyenstueber, A.S.E.

1985-11-01

The Voelwater Subgroup, of the Proterozoic Transvaal Sequence, in the Hotazel area, is preserved in five structurally controlled basins, on the eastern side of the Dimoten syncline. The Subgroup represents a relatively undisturbed unit of mixed volcanogenic - chemical sedimentary rocks. The Hotazel Formation within the Voelwater Subgroup, consists of a finely banded carbonate - silicate - hematite - manganese lutite sequence of banded iron-formation and must be unique in that it contains the world's largest land-based repository of manganese. Twenty-one drill cores, sampled lithologically at intervals of approximately one metre through the total sedimentary sequence, were studied by microscopic, X-ray diffraction and electron microprobe methods. The mineralogy of the Voelwater Subgroup was studied on a regional scale, with the emphasis on the minerals within the manganese beds of the Hotazel Formation. The objective of the study was: a. To study the variation and distrubution of minerals in the various manganese ores on a regional scale. b. To compare the mineralogical differences of the different ores mined, in order to gain a better understanding of their metallurgical behaviour. c. To try to locate high-grade manganese ore target areas for future exploration, with the aid of mineralogical information. d. To try to establish the origin of the manganese in the Voelwater Formation. e. To study the relationship of the manganese units with the adjacent chemical sediments of the Hotazel Formation

Hot Ductility Behavior of Boron Containing Microalloyed Steels with Varying Manganese Contents

Science.gov (United States)

Brune, Tobias; Senk, Dieter; Walpot, Raphael; Steenken, Bernhard

2015-02-01

The hot ductility is measured for six different steel grades with different microalloying elements and with varying manganese contents using the hot tensile test machine with melting/solidification unit at the Department of Ferrous Metallurgy RWTH Aachen University. To identify the influence of manganese on hot ductility, tests are performed with varying the manganese content from 0.7 to 18.2 wt pct, a high manganese steel. Additionally, the effect of different cooling and strain rates is analyzed by changing the particular rate for selected samples in the minima. To investigate and detect the cause of cracking during testing, the fracture surfaces in the ductility minima are considered with scanning electron microscope-energy dispersive X-ray spectroscopy. Thermodynamic modeling is conducted on basis of the commercial software ThermoCalc©. A sharp decrease of the hot ductility is recognizable at 1398 K (1125 °C), at only 0.7 wt pct manganese because of the low manganese to sulfur ratio. The grades with a Mn content up to 1.9 wt pct show a good ductility with minimal ductility loss. In comparison, the steel grade with 18.2 wt pct has a poor hot ductility. Because of the formation of complex precipitates, where several alloying elements are involved, the influence of boron on hot ductility is not fully clarified. By increasing the cooling rate, the reduction of area values are shifted to smaller values. For high test temperatures, these measured values are decreased for lower strain rates. Thereby, an early drop of the ductility is noticeable for the high temperatures around 1373 K (1100 °C).

Research on rejection performance of reverse osmosis to manganese in simulated radioactive wastewater

International Nuclear Information System (INIS)

Kong Jinsong; Wang Xiaowei

2012-01-01

In order to reveal the performance of reverse osmosis applied in the radioactive wastewater treatment, treatment experiments are carried out on a pilot RO equipment using wastewater containing manganese nuclide. Results show that the rejection ratio of RO to manganese is almost not influenced by the operation pressure and the ration of reclaiming, and has no direct relation with the salt rejection ratio. The ratio of manganese rejection is more than 95% and can meet the requirement on the disposal of radioactive wastewater produced by pressurized water reactors. (authors)

Solvent extractions applications to hydrometallurgy. Pt.III: Nickel, cobalt, manganese and ocean nodules

International Nuclear Information System (INIS)

Amer, S.

1981-01-01

The main applications of solvent extraction to the hydrometallurgy of nickel, cobalt, manganese and manganese rich ocean nodules, which also contain nickel, cooper and cobalt, are exposed. A short description of the processes with commercial applications is made. (author)

Longitudinal and contemporaneous manganese exposure in apartheid-era South Africa: Implications for the past and future.

Science.gov (United States)

Hess, Catherine A; Smith, Martin J; Trueman, Clive; Schutkowski, Holger

2015-03-01

Manganese is a potent environmental toxin, with significant effects on human health. Manganese exposure is of particular concern in South Africa where in the last decade, lead in gasoline has been replaced by methylcyclopentadienyl manganese tricarbonyl (MMT). We investigated recent historical levels of manganese exposure in urban Gauteng, South Africa prior to the introduction of MMT in order to generate heretofore non-existent longitudinal public health data on manganese exposure in urban South Africans. Cortical bone manganese concentration was measured by inductively coupled plasma mass spectrometer in 211 deceased adults with skeletal material from a fully identified archived tissue collection at the University of Pretoria, South Africa. All tissues came from individuals who lived and died in urban Gauteng (Transvaal), between 1958 and 1998. Median Mn concentration within the sampled tissues was 0.3μgg -1 , which is within reported range for bone manganese concentration in non-occupationally exposed populations and significantly below that reported in individuals environmentally exposed to MMT. No significant differences were seen in bone Mn between men and women or in individuals of different ethnicity, which further suggests environmental, as opposed to occupational exposure. There were no significant temporal or geographic differences in bone Mn. The results suggest that Mn exposure was low and uniformly distributed across the whole population prior to the introduction of MMT as a gasoline additive. In addition, should manganese exposure follow the same patterns as vehicle-emitted lead, a clear pattern of exposure will emerge with individuals in the urban core facing the greatest manganese exposure. Copyright © 2014 Elsevier Inc. All rights reserved.

Nanostructural evolution from nanosheets to one-dimensional nanoparticles for manganese oxide

International Nuclear Information System (INIS)

Pan, Hongmei; Kong, Xingang; Wen, Puhong; Kitayama, Tomonori; Feng, Qi

2012-01-01

Highlights: ► Nanosheets were transformed to other one-dimensional nanoparticles. ► Nanofibers, nanotubes, nanoribbons, and nanobelts were obtained. ► Nanoparticle morphology can be controlled with organic amines. ► Organic amines act as morphology directing agent. -- Abstract: This paper introduces a novel hydrothermal soft chemical synthesis process for manganese oxide nanostructured particles using two-dimensional manganese oxide nanosheets as precursor. In this process, a birnessite-type manganese oxide with a layered structure was exfoliated into its elementary layer nanosheets, and then the nanosheets were hydrothermally treated to transform the two-dimensional morphology of the nanosheets to one-dimensional nanoparticles. The manganese oxide nanofibers, nanotubes, nanobelts, nanoribbons, and fabric-ribbon-like particles constructed from nanofibers or nanobelts were obtained using this hydrothermal soft chemical process. The nanostructural evolution from the two-dimensional nanosheets to the one-dimensional nanoparticles was characterized by XRD, SEM, TEM, and TG-DTA analysis. The morphology and nanostructure of the products are strongly dependent on the molecular dimension of organic amine cations added in the reaction system. The organic amine cations act as a morphology directing agent in the nanostructural evolution process.

Antiferromagnetic iridium-manganese intermediate layers for perpendicular recording media (invited)

Science.gov (United States)

Srinivasan, Kumar; Piramanayagam, S. N.; Sbiaa, Rachid; Kay, Yew Seng; Tan, Hang Khume; Wong, Seng Kai

2009-04-01

Current generation of cobalt-oxide-based perpendicular magnetic recording media uses single or dual ruthenium intermediate layers in order to grow crystallographically textured, and magnetically isolated granular media. In this work, the potential advantages of an antiferromagnetic iridium-manganese intermediate layer directly under the recording layer are highlighted. Owing to its close lattice matching with hexagonal cobalt, iridium-manganese which has the L12, or AuCu3-type crystal structure, can support the heteroepitaxial growth of the cobalt-based recording layer. In one of the media schemes described here, (111) textured iridium-manganese thin film was grown on 7.5 nm thick ruthenium layer. On the iridium-manganese as segregation layer, the Co-oxide-based magnetic recording layer showed perpendicular texture with Δθ50 below 4°, coercivity of over 4000 Oe alongside magnetic exchange decoupling, average grain sizes of 6 nm with distributions under 14%, and improved thermal stability. Measurements of the anisotropy constant did not show any significant change and even an IrMn capping layer was observed to improve the thermal stability. The possible mechanisms through which the IrMn layer could affect the thermal stability are hypothesized. The initial layers of the magnetic recording layer on IrMn segregation layers also showed exchange-decoupled and segregated grains, which is unlike that observed on Ru segregation layers. In a second media scheme, (111) textured iridium-manganese thin film was grown on a crystalline soft magnetic underlayer belonging on top of amorphous soft underlayers. In this scheme, partial pinning of the soft underlayer due to exchange-bias interaction with the IrMn layer was observed. This scheme offers the possibility to reduce the intermediate layer thickness, thus improve media writability, and with further optimization, could potentially facilitate the approach toward 1 Tbits/in.2.

Iron and manganese deposits in Uruguay

International Nuclear Information System (INIS)

Alvarado, B.

1959-01-01

This report is the results of the study carried out for the United Nations expert which the main object was: the study of the information available about iron and manganese formation in Uruguay, as well as the main researching deposit to determinate economical possibilities in the exportation.

Absorption of manganese and iron in a mouse model of hemochromatosis.

Directory of Open Access Journals (Sweden)

Jonghan Kim

Full Text Available Hereditary hemochromatosis, an iron overload disease associated with excessive intestinal iron absorption, is commonly caused by loss of HFE gene function. Both iron and manganese absorption are regulated by iron status, but the relationships between the transport pathways of these metals and how they are affected by HFE-associated hemochromatosis remain poorly understood. Loss of HFE function is known to alter the intestinal expression of DMT1 (divalent metal transporter-1 and Fpn (ferroportin, transporters that have been implicated in absorption of both iron and manganese. Although the influence of HFE deficiency on dietary iron absorption has been characterized, potential effects on manganese metabolism have yet to be explored. To investigate the role of HFE in manganese absorption, we characterized the uptake and distribution of the metal in Hfe (-/- knockout mice after intravenous, intragastric, and intranasal administration of (54Mn. These values were compared to intravenous and intragastric administration of (59Fe. Intestinal absorption of (59Fe was increased and clearance of injected (59Fe was also increased in Hfe(-/- mice compared to controls. Hfe (-/- mice displayed greater intestinal absorption of (54Mn compared to wild-type Hfe(+/+ control mice. After intravenous injection, the distribution of (59Fe to heart and liver was greater in Hfe (-/- mice but no remarkable differences were observed for (54Mn. Although olfactory absorption of (54Mn into blood was unchanged in Hfe (-/- mice, higher levels of intranasally-instilled (54Mn were associated with Hfe(-/- brain compared to controls. These results show that manganese transport and metabolism can be modified by HFE deficiency.

Autoradiography of manganese: accumulation and retention in the pancreas

International Nuclear Information System (INIS)

Lyden, A.; Lindquist, N.G.; Larsson, B.S.

1983-01-01

By means of whole-body autoradiography, the general distribution of 54 MnCl 2 was studied in mice and a Marmoset monkey. High accumulation and retention were observed in the pancreas in both species. Gamma counting experiments in mice after a single intravenous injection of 54 MnCl 2 showed that the level in the pancreas exceeded that of the liver at all survival times (20 min. - 30 days). Also in the monkey, the concentration in the pancreas exceeded that of the liver, and the pancreas had the highest tissue/liver ratio of the organs measured at 24 hours after injection. The high uptake and long retention in the pancreas suggest that manganese is of importance for the pancreatic function but also that the pancreas may be a target organ for manganese toxicity. Positron tomography, using 11 C-labelled amino acids, has been found to be a promising diagnostic technique for the study of pancreatic disease. Positron emitting manganese isotopes may be worth further studies as possible agents for pancreatic imaging. (author)

Study and determination of the ratio atoms between hydrogen and manganese in the manganese sulphate bath: procedure and calculation

International Nuclear Information System (INIS)

Castro, Leonardo C. de; Pereira, Walsan W.; Fonseca, Evaldo S.; Leite, Sandro P.

2007-01-01

The Brazilian Neutron Laboratory (LN) is part of the National Laboratory of Ionising Radiation of Metrology (LNMRI/IRD). It operates a system for absolute standardization for the measurement of the neutrons sources fluence. The Manganese Sulphate Bath (MSB) is part of this measurement system and was donated by the Bureau International de Poids et Measures (BIPM) in 1996. Since then at LN has become a fulfilled inquiry and measurements of fluence rate of a neutrons source Q. LN has carried through activities for the maintenance and dissemination of the reference values for this primary standard. Currently LN advances in two work lines: One of them is the study of the bath sensibility of the detection system (e), and the other is the study of f parameter, that measures the fraction of captured neutrons by 55 Mn. In the present work, we dedicate special attention to the measurement of the neutron fraction that depends on the amount of ratio atoms between hydrogen and manganese. A revision of the procedures and the experience involved with the measurement system gave chance to evaluate points for a metrology refinement leading to lower uncertainties and greater reliability degree values. To obtain the cited refinement, the following stages had been fulfilled: Firstly, the development of a tool for confection of standardized crucibles. Secondly, the characterization of the muffle used in the work through the survey of heating slopes. And finally, the study of the volatility with the temperature of manganese sulphate (MnSO4 + H2O) through a thermo-gravimetric analysis in the own muffle conditions used in the work. It was observed that the steady temperature of operation in the quantification of the Manganese in the solution meets above of 350 deg C and this caused a significant improvement over the measurement proceeding. This work demonstrates that the improvements in the proceeding for the determination of the NH/NMn ratio leads to the one of the goals longed for this

Sublethal effects of cadmium, manganese, lead, zinc and iron on the ...

African Journals Online (AJOL)

The toxicological evaluations of cadmium, iron, manganese, lead and zinc were carried out against albino mice model, Mus musculus. On the basis of 96 hrLC50 value, cadmium (0.47 mM) was found to be the most toxic followed by zinc (2.40 mM), lead (2.42 mM), iron (4.25 mM) and manganese (5.70 mM) was least toxic.

Determination of manganese in tissues by neutron activation analysis using an antomony pentoxide column

International Nuclear Information System (INIS)

Miyata, S.; Nakamura, S.; Toyoshima, M.; Hirata, Y.; Saito, M.; Kameyama, M.; Matsushita, R.; Koyama, M.

1980-01-01

A rapid and accurate method is presented for the determination of manganese in biological samples, using neutron activation analysis. Biological samples were irradiated at 5000 kW for 30 min. The samples were ashed on a hot plate with 14 mol/l HNO 3 and 6 mol/l HClO 4 , and resolved in 1 mol/l HClO 4 . 24 Na and 42 K were removed by passing each sample through an antimony pentoxide column. 54 Mn was added as a tracer to calculate the ratio of manganese recovered by the separation procedure. Recovery was over 90%. This method was applied in order to determine manganese in various tissues. In the cervical spinal cord of the controls, the mean manganese concentrations in the anterior horn, the lateral and the posterior columns were 1.14, 1.06 and 0.90 ng/mg of dried tissue, respectively. In two cases of amyotrophic lateral sclerosis the manganese concentrations in the cervical spinal cord were elevated, particularly in the anterior horn and the lateral column. (Auth.)

The separation of trace elements in manganese dioxide

International Nuclear Information System (INIS)

Jones, E.A.; Dixon, K.

1981-01-01

Separations from manganese are discribed for (a)Al(III), Mo(VI), V(V), and Ti(IV), and (b)trace elements in general. In the first separation, a combined anion-cation exchange, the oxalate complexes are absorbed onto the anionic BIO.RAD 1-X8 resin. V(V) and Al(III) are then eluted into a cation-exchange column from which they are eluted successively, Mo(VI) and Ti(IV) then being eluted from the anionic resin. In the second separation, up to 2g of manganese is absorbed onto BIO.RAD AG 50W-X8 resin, from which V(V) is eluted with dilute hydrochloric acid prior to the elution of Co(II), Cu(II), Zn(II), Cd(II), Fe(III), As(III), Sb(III), Mo(VI), W(VI), and Sn(II) with a mixture of 1 M hydrochloric acid, 80 per cent acetone, and 0,1 per cent hydrogen peroxide. Mn(11) is eluted next with a mixture of 0,75M hydrochloric acid and 90 per cent acetone, after which the remaining cations are eluted with 4M hydrochloric acid. Satisfactory recoveries ranging from 0,8 to 60 mg/l were obtained for 18 of the 21 elements tested. After concentration by evaporation, final measurements were made by the use of atomic-absorption spectrophotometry, or direct-reading spectrometry with excitation from an inductively coupled plasma source. Comparative results were obtained with atomic-absorption procedures where the manganese was not separated. However, the separation procedure can reduce the time required for analysis by the direct method because it limits the number of dilutions necessary and eliminates the need for the use of the method of additions to compensate for interferences from manganese

Chelation in metal intoxication. V. Lowering of manganese content in poisoned rat organs

Energy Technology Data Exchange (ETDEWEB)

Tandon, S K; Mathur, A K

1976-01-01

Metal chelation has been considered useful in the management of manganese poisoning to a considerable extent. Our own studies in this direction have shown that some polyaminocarboxylic acids and a few amino acids are effective in not only removing manganese from the vital organs of experimentally poisoned animals but also in restoring certain metal induced biochemical and histological changes in such organs. Further, the success of p-aminosalicylic acid (PAS), a chemotherapeutic agent for tuberculosis, in manganese mobilization has led us to examine some other structurally related compounds together with a few other possible metal binding agents for their ability to remove excess metal from the organs, their sub-cellular fractions and blood cells of manganese administered rats and to investigate if there exists any relationship between the structure of such compounds and their metal mobilizing capacity. The present communication deals with the results of these investigations.

Preparation of MnO nanofibers by novel hydrothermal treatment of manganese acetate/PVA electrospun nanofiber mats

International Nuclear Information System (INIS)

Barakat, Nasser A.M.; Park, Soo Jin; Khil, Myung Seob; Kim, Hak Yong

2009-01-01

In the present study, manganese monoxide (MnO) which is hard to prepare because of the chemical activity of the manganese metal has been synthesized in nanofibrous form. An electrospun manganese acetate/poly(vinyl alcohol) nanofiber mats have been hydrothermally treated by novel strategy. The treatment process was based on producing of water gas (Co and H 2 ) to eliminate the polymer and reduced the manganese acetate to manganese monoxide. The process was carried out by heating the dried nanofiber mates at 400 deg. C for 3 h in an especial designed reactor in which a stream of water vapor was passing through a bed of an activated carbon. The obtained physiochemical characterization results indicated that the proposed hydrothermal treatment process does have the ability to produce pure MnO nanofibers with good crystallinity.

Preparation of MnO nanofibers by novel hydrothermal treatment of manganese acetate/PVA electrospun nanofiber mats

Energy Technology Data Exchange (ETDEWEB)

Barakat, Nasser A.M. [Chemical Engineering Department, Faculty of Engineering, El-Minia University, El-Minia (Egypt); Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)], E-mail: nasbarakat@yahoo.com; Park, Soo Jin [Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Khil, Myung Seob [Department of Textile Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Hak Yong [Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Textile Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)], E-mail: khy@chonbuk.ac.kr

2009-06-15

In the present study, manganese monoxide (MnO) which is hard to prepare because of the chemical activity of the manganese metal has been synthesized in nanofibrous form. An electrospun manganese acetate/poly(vinyl alcohol) nanofiber mats have been hydrothermally treated by novel strategy. The treatment process was based on producing of water gas (Co and H{sub 2}) to eliminate the polymer and reduced the manganese acetate to manganese monoxide. The process was carried out by heating the dried nanofiber mates at 400 deg. C for 3 h in an especial designed reactor in which a stream of water vapor was passing through a bed of an activated carbon. The obtained physiochemical characterization results indicated that the proposed hydrothermal treatment process does have the ability to produce pure MnO nanofibers with good crystallinity.

Gold, iron and manganese in central Amapá, Brazil

Directory of Open Access Journals (Sweden)

Wilson Scarpelli

Full Text Available ABSTRACT: Greenstone belts with deposits of gold, iron and manganese are common in the Paleoproterozoic Maroni-Itacaiunas Tectonic Province of the Guiana Shield. In Brazil, in the State of Amapá and northwest of Pará, they are represented by the Vila Nova Group, constituted by a basal unit of metabasalts, covered by metasediments of clastic and chemical origin. The basal metasediments, the Serra do Navio Formation, are made of a cyclothem with lenses of manganese marbles at the top of each cycle. Under the intense weathering of the Amazon, these lenses were oxidized to large deposits of high-grade manganese oxides. The exploitation of these oxides left behind the manganese carbonates and low-grade oxides. The overlaying Serra da Canga Formation presents a calcium and magnesium domain grading to an iron domain with banded silicate and oxide iron formations, mined for iron ores. Overlapping structures and superposed metamorphic crystallizations indicate two phases of dynamothermal metamorphism, the first one with axis to north-northeast and the second one to northwest, with an intermediate phase of thermal metamorphism related to syntectonic granitic intrusions. Shears oriented north-south, possibly formed during the first dynamothermal metamorphism and reactivated in the second, are ideal sites for hydrothermalism and gold mineralization, which is greater when occurs in iron formation and carbonate-bearing rocks, as it happened at the Tucano mine. Layered mafic-ultramafic intrusions in the greenstones represent a potential for chromite and platinum group elements. Pegmatites are source of cassiterite and tantalite exploited from alluvial deposits.

Irradiation alternative method of manganese sulfate solution by a Pu-Be source for efficiency measurements; Metodo alternativo de irradiacao da solucao de sulfato de manganes por uma fonte de Pu-Be para medicoes de eficiencia

Energy Technology Data Exchange (ETDEWEB)

Silva, Fellipe Souza da; Martins, Marcelo Marques; Pereira, Walsan Wagner, E-mail: fellipess@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2015-07-01

This study intends to create an alternative irradiation system from a Plutonium-Beryllium source for manganese sulphate solution using the Monte Carlo code. Thus seeking to eliminate the issue of institutes that do not have reactors or particle accelerators in its infrastructure, in order to optimize and provide independence for them to carry out efficiency measurements of MnSO{sub 4} solution in their own locality. The Monte Carlo simulations defined the technical features of this new system so that the solution reaches the maximum neutron capture by manganese in solution. (author)

Structural and surface changes of cobalt modified manganese oxide during activation and ethanol steam reforming reaction

Science.gov (United States)

Gac, Wojciech; Greluk, Magdalena; Słowik, Grzegorz; Turczyniak-Surdacka, Sylwia

2018-05-01

Surface and structural changes of unmodified manganese and cobalt-manganese oxide during activation and ethanol steam reforming reaction conditions (ESR) were studied by means of X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction/oxidation (TPR/TPO) and transmission electron microscopy. It was shown that synthesis of cobalt manganese oxide by the redox precipitation method led to the formation of strongly dispersed cobalt ionic species within cryptomelane-based manganese oxide structure. Development of large cube-like MnO nanoparticles with spherical cobalt metallic crystallites decorated by manganese oxide on the high oxidation state and potassium species was observed during reduction. Cobalt manganese catalyst showed high initial activity and selectivity to H2 and CO2 in ethanol stem reforming reaction in the range of 390-480 °C. The drop of ethanol conversion and changes of selectivity with the time-on-stream were observed. An increase of reaction temperature led to intensification of deactivation phenomena. TEM studies evidenced coexistence of Co and CoOx nanoparticles formed under ethanol steam reforming conditions, partially covered by filamentous and encapsulating carbonaceous deposits.

Highly Conductive One-Dimensional Manganese Oxide Wires by Coating with Graphene Oxides

Science.gov (United States)

Tojo, Tomohiro; Shinohara, Masaki; Fujisawa, Kazunori; Muramatsu, Hiroyuki; Hayashi, Takuya; Ahm Kim, Yoong; Endo, Morinobu

2012-10-01

Through coating with graphene oxides, we have developed a chemical route to the bulk production of long, thin manganese oxide (MnO2) nanowires that have high electrical conductivity. The average diameter of these hybrid nanowires is about 25 nm, and their average length is about 800 nm. The high electrical conductivity of these nanowires (ca. 189.51+/-4.51 µS) is ascribed to the homogeneous coating with conductive graphene oxides as well as the presence of non-bonding manganese atoms. The growth mechanism of the nanowires is theoretically supported by the initiation of morphological conversion from graphene oxide to wrapped structures through the formation of covalent bonds between manganese and oxygen atoms at the graphene oxide edge.

Removal of iron and manganese from groundwater: a study of using potassium permanganate and sedimentation

Directory of Open Access Journals (Sweden)

Elsheikh Mohamed

2018-01-01

Full Text Available Experiments are done for different combinations of Fe+2 and Mn+2 concentrations. The obtained results show that Potassium Permanganate (PP gives good results in iron and manganese removal. By using PP dose near to half of the theoretically required one, it can remove up to 100 % and 90 % of iron and manganese, respectively over different tested concentrations at pH=7.0. Increasing rate of filtration influences the Mn+2 removal process obviously. Sedimentation is required when combined concentrations of iron and manganese are greater than 5.0 ppm to reduce filter rapid clogging. Using conventional treatment with adding alum, flocculation, sedimentation and filtration can remove up to 97% and 18% of iron and manganese, respectively. Using PP in addition to alum enhances manganese removal but decreases iron removal. However, using alum with increasing pH to 10 leads to 100 % and 95 % of Fe+2 and Mn+2 removal and increases filter working period.

On-line determination of manganese in solid seafood samples by flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Yebra, M.C.; Moreno-Cid, A.

2003-01-01

Manganese is extracted on-line from solid seafood samples by a simple continuous ultrasound-assisted extraction system (CUES). This system is connected to an on-line manifold, which permits the flow-injection flame atomic absorption spectrometric determination of manganese. Optimisation of the continuous leaching procedure is performed by an experimental design. The proposed method allows the determination of manganese with a relative standard deviation of 0.9% for a sample containing 23.4 μg g -1 manganese (dry mass). The detection limit is 0.4 μg g -1 (dry mass) for 30 mg of sample and the sample throughput is ca. 60 samples per hour. Accurate results are obtained by measuring TORT-1 certified reference material. The procedure is finally applied to mussel, tuna, sardine and clams samples

Furfural and 5-hydroxymethyl-furfural degradation using recombinant manganese peroxidase.

Science.gov (United States)

Yee, Kelsey L; Jansen, Lauren E; Lajoie, Curtis A; Penner, Michael H; Morse, Lettie; Kelly, Christine J

2018-01-01

Biomass pretreatment-derived degradation compounds, such as furfural and 5-hydroxymethyl-furfural (HMF), inhibit the growth of fermentation microorganisms that utilize biomass to produce fuels and chemicals. Here we report that recombinant manganese peroxidase (rMnP) produced from the yeast Pichia pastoris can degrade furfural and HMF making them less toxic to microorganisms. Treatment with rMnP or manganese(III) acetate reduced furfural and HMF concentrations in a dose-dependent manner. Furfural disappearance was accompanied by malonate disappearance and accumulation of four distinct degradation products. Furfural was more readily degraded by rMnP and manganese(III) acetate than HMF. Growth assays using Saccharomyces cerevisiae indicated that rMnP treatment reduced the toxicity of furfural and HMF. This work provides an avenue to use rMnP to increase the growth of fermentation microorganisms that are inhibited by toxic compounds derived from pretreatment of biomass. Copyright © 2017 Elsevier Inc. All rights reserved.

Fluxes of dissolved aluminum and manganese to the Weddell Sea and indications for manganese co-limitation

NARCIS (Netherlands)

Middag, R.; de Baar, H.J.W.; Klunder, M.B.; Laan, P.

2013-01-01

The trace metals aluminum (Al) and manganese (Mn) were studied in the Weddell Sea in March 2008. Concentrations of dissolved Al ([Al]) were slightly elevated (0.23-0.35 nmol L-1) in the surface layer compared to the subsurface minimum (0.07-0.21 nmol L-1) observed in the winter water. Atmospheric

Daily dietary intake of iron, copper, zinc and manganese in a Spanish population.

Science.gov (United States)

Rubio, Carmen; Gutiérrez, Angel José; Revert, Consuelo; Reguera, Juan Ignacio; Burgos, Antonio; Hardisson, Arturo

2009-11-01

To evaluate the daily dietary intake of essential metals in the Canary Islands, the iron, copper, zinc and manganese contents in 420 food and drink samples collected in local markets were analysed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The estimated daily dietary intakes of iron, copper, zinc and manganese are 13.161 mg/day, 2.098 mg/day, 8.954 mg/day and 2.372 mg/day, respectively. The iron dietary intake was found to be below the recommendations fixed for adult women, while the copper and manganese dietary intakes fulfilled the Recommended Dietary Allowances. The mean daily intake of zinc was below the Recommended Dietary Allowance. Cereals were found to be the food group that contributed most to the intake of these metals. While the island of El-Hierro presented iron, copper, zinc and manganese mean intakes over the estimated intakes for the whole archipelago, Fuerteventura island showed the lowest intakes. Tenerife and Fuerteventura showed the lowest iron intakes, being below the recommendations.

Absorption of Manganese and Iron in a Mouse Model of Hemochromatosis

Science.gov (United States)

Kim, Jonghan; Buckett, Peter D.; Wessling-Resnick, Marianne

2013-01-01

Hereditary hemochromatosis, an iron overload disease associated with excessive intestinal iron absorption, is commonly caused by loss of HFE gene function. Both iron and manganese absorption are regulated by iron status, but the relationships between the transport pathways of these metals and how they are affected by HFE-associated hemochromatosis remain poorly understood. Loss of HFE function is known to alter the intestinal expression of DMT1 (divalent metal transporter-1) and Fpn (ferroportin), transporters that have been implicated in absorption of both iron and manganese. Although the influence of HFE deficiency on dietary iron absorption has been characterized, potential effects on manganese metabolism have yet to be explored. To investigate the role of HFE in manganese absorption, we characterized the uptake and distribution of the metal in Hfe −/− knockout mice after intravenous, intragastric, and intranasal administration of 54Mn. These values were compared to intravenous and intragastric administration of 59Fe. Intestinal absorption of 59Fe was increased and clearance of injected 59Fe was also increased in Hfe−/− mice compared to controls. Hfe −/− mice displayed greater intestinal absorption of 54Mn compared to wild-type Hfe+/+ control mice. After intravenous injection, the distribution of 59Fe to heart and liver was greater in Hfe −/− mice but no remarkable differences were observed for 54Mn. Although olfactory absorption of 54Mn into blood was unchanged in Hfe −/− mice, higher levels of intranasally-instilled 54Mn were associated with Hfe−/− brain compared to controls. These results show that manganese transport and metabolism can be modified by HFE deficiency. PMID:23705020

Spectroscopic characterization of manganese-doped alkaline earth ...

Indian Academy of Sciences (India)

The shapes of spectra are also changed with varying alkaline earth ions content. ... of manganese ion and electrical properties of glass contain- ing mobile ions like .... octahedral crystal field are located above the ground 6S state. Figure 2.

On the manganese content of the egg of Oryzias latipes and its change during the early development

International Nuclear Information System (INIS)

Hori, R.; Iwasaki, S.I.

1976-01-01

The content of manganese of the egg of Oryzias latipes was determined by atomic absorption spectrophotometry and activation analysis. The amount of manganese in the unfertilized egg was 0.51 mμg and increased remarkably in one hour after fertilization. Although the increasing rate became gradually lower in further stages, the content of manganese amounted to 2.61 mμg in the embryo after gastrulation. Tracer-experiments showed that the egg accumulated manganese positively from the surrounding medium during the short time after fertilization. (author)

The complex compounds of manganese (II) with poly dental ligands and polyhedron borane anions

International Nuclear Information System (INIS)

Buranova, S.A.

1996-01-01

The purpose of the present work is synthesis of complex compounds of manganese with organic ligands. Their studying by spectroscopic methods purposely to determinate the influence of borane anions on composition and structure of coordinating sphere of manganese

Efficient and selective N-alkylation of amines with alcohols catalysed by manganese pincer complexes

Science.gov (United States)

Elangovan, Saravanakumar; Neumann, Jacob; Sortais, Jean-Baptiste; Junge, Kathrin; Darcel, Christophe; Beller, Matthias

2016-01-01

Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C–N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the selective N-alkylation of amines with alcohols can be catalysed by defined PNP manganese pincer complexes. A variety of substituted anilines are monoalkylated with different (hetero)aromatic and aliphatic alcohols even in the presence of other sensitive reducible functional groups. As a special highlight, we report the chemoselective monomethylation of primary amines using methanol under mild conditions. PMID:27708259

Effects of manganese exposure on visuoperception and visual memory in schoolchildren.

Science.gov (United States)

Hernández-Bonilla, D; Escamilla-Núñez, C; Mergler, D; Rodríguez-Dozal, S; Cortez-Lugo, M; Montes, S; Tristán-López, L A; Catalán-Vázquez, M; Schilmann, A; Riojas-Rodriguez, Horacio

2016-12-01

Manganese (Mn) is an essential metal involved in multiple physiological functions. Environmental exposure to airborne Mn is associated with neurocognitive deficits in humans. Children, whose nervous system is in development, are particularly susceptible to Mn neurotoxicity. The objective of this study was to assess the association between Mn environmental exposure, and effects on visuoperception and visual memory in schoolchildren. We assessed schoolchildren between 7 and 11 years old, with similar socioeconomic status, from the mining district of Molango (n=148) and Agua Blanca (n=119, non-mining area) in Hidalgo state, Mexico. The Rey-Osterrieth Complex Figure (ROCF) test was used to assess visuoperception and short-term visual memory. Hair manganese (MnH) concentrations were determined. Linear regression models were constructed to estimate the associations between MnH and ROCF scores, adjusted for potential confounders. The geometric mean MnH was nine times higher in schoolchildren from the Mn mining area (5.25μg/g) than in schoolchildren from the non-mining area (0.55μg/g). For the ROCF Copy trial, MnH was significantly associated with an increase in distortion errors (tangency, closure), angle errors, overtracing (partial overtracing). In the Immediate Recall trial, MnH was significantly associated with increased overtracing (partial overtracing) and omissions, and negatively associated with the number of perceptual drawn units, total score and percentage immediate recall. MnH is associated with alterations in visuoperception and short-term visual memory in schoolchildren exposed to airborne Mn. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of manganese and manganese-nitrogen applications on growth and nutrition of Douglas-fir seedlings.

Science.gov (United States)

M. A. Radwan; John S. Shumway; Dean S. DeBell

1979-01-01

Effects of manganese (Mn) on Douglas-fir grown in soil, with and without urea, and in nutrient solution were investigated. In addition, Mn sorption by forest soils was evaluated. Results show that Douglas-fir does not respond to added Mn and is quite tolerant to high Mn levels. Moreover, Mn sorption by soils is high. It is doubtful that Mn toxicity is of practical...

Influence of metallic additives on manganese ferrites sintering

Science.gov (United States)

Shevelev, S. A.; Luchnikov, P. A.; Yarullina, A. R.

2018-01-01

Influence of cuprum nanopowder additive received by electric explosion on the process of manganese ferrites MgFe2O4 consolidating at thermal sintering was researched by dilatometry method. Cuprum nanopowder at a rate of 5 mass % was added into the original commercial-grade powder of manganese ferrite MgFe2O4. Powder mixture was numerously blended with screening for better blending before pressing. Powder compacts were formed by cold one-axle static pressing. It was proved that introduction of cuprum additive caused shrinkage increase at final heating stage. There was abnormal compact enlarging at sintering in the air at isothermal stage; the specified process was not observed in vacuum. This difference can be explained by changes in conditions of gaseous discharge from volume of pores.

Advanced manganese oxide material for rechargeable lithium cells

Energy Technology Data Exchange (ETDEWEB)

Atwater, Terrill B.; Salkind, Alvin J. [Rutgers University, Piscataway, NJ (United States)

2006-11-22

A family of potassium-doped manganese oxide materials were synthesized with the stoichiometric formula Li{sub 0.9-X}K{sub X}Mn{sub 2}O{sub 4}, where X=0.0-0.25 and evaluated for their viability as a cathode material for a rechargeable lithium battery. A performance maximum was found at X=0.1 where the initial specific capacity for the lithium-potassium-doped manganese dioxide electrochemical couple was 130mAhg{sup -1} of active cathode material. The discharge capacity of the system was maintained through 90 cycles (95% initial capacity). Additionally, the capacity was maintained at greater than 90% initial discharge through 200 cycles. Other variants demonstrated greater than 75% initial discharge through 200 cycles at comparable capacity. (author)

Charpy impact behavior of manganese-stabilized martensitic steels

International Nuclear Information System (INIS)

Hu, W.L.; Gelles, D.S.

1986-05-01

Tests were conducted to evaluate the irradiation-induced shift in ductile-to-brittle transition behavior of two manganese stabilized martensitic steels. Miniature Charpy specimens were fabricated from two heats of steel similar in composition to HT-9 but with 0.1% C and Mn contents ranging from 3.3 to 6.6.%. The 3.3% Mn steel showed a transition temperature similar to that of HT-9 in both the unirradiated condition and in specimens irradiated to 11.3 dpa. The steel containing 6.6% Mn exhibited a higher transition temperature after irradiation than the steel containing 3.3% Mn. The upper shelf energy (USE) after irradiation for the manganese stabilized alloys was much higher than for HT-9. 6 refs., 3 figs., 2 tabs

Topographical Distribution of Arsenic, Manganese, and Selenium in the Normal Human Brain

DEFF Research Database (Denmark)

Larsen, Niels Agersnap; Pakkenberg, H.; Damsgaard, Else

1979-01-01

The concentrations of arsenic, manganese and selenium per gram wet tissue weight were determined in samples from 24 areas of normal human brains from 5 persons with ages ranging from 15 to 81 years of age. The concentrations of the 3 elements were determined for each sample by means of neutron...... activation analysis with radiochemical separation. Distinct patterns of distribution were shown for each of the 3 elements. Variations between individuals were found for some but not all brain areas, resulting in coefficients of variation between individuals of about 30% for arsenic, 10% for manganese and 20......% for selenium. The results seem to indicate that arsenic is associated with the lipid phase, manganese with the dry matter and selenium with the aqueous phase of brain tissue....

Effect of Organic Binders on The Quality of Manganese Ore Sinter Fines Briquettes

International Nuclear Information System (INIS)

Mohamed, F. M.; Ahmed, Y.M.Z.; Shalabi, M. E. H.

2004-01-01

Sinai Manganese Company imports the manganese ore sinter from abroad for ferromanganese alloy production. Large quantities of manganese ore sinter fines are produced in this process. These fines must be agglomerated to a suitable size in order to be reused for charging the electric arc furnace. The aim of this work is studying the briquetting ability of these fines using organic binders such as starch and bitumen. The results showed that, the suitable briquettes were produced with the addition of 5 % of starch and 20% H 2 O under pressure 3 ton/cm 2 or 8 % bitumen under pressure 4 ton/cm 2 and 3 days curing time

Diode laser heat treatment of lithium manganese oxide films

International Nuclear Information System (INIS)

Pröll, J.; Kohler, R.; Mangang, A.; Ulrich, S.; Bruns, M.; Seifert, H.J.; Pfleging, W.

2012-01-01

The crystallization of lithium manganese oxide thin films prepared by radio frequency magnetron sputtering on stainless steel substrates under 10 Pa argon pressure is demonstrated by a laser annealing technique. Laser annealing processes were developed as a function of annealing time and temperature with the objective to form an electrochemically active lithium manganese oxide cathode. It is demonstrated, that laser annealing with 940 nm diode laser radiation and an annealing time of 2000 s at 600 °C delivers appropriate parameters for formation of a crystalline spinel-like phase. Characteristic features of this phase could be detected via Raman spectroscopy, showing the characteristic main Raman band at 627 cm -1 . Within cyclic voltammetric measurements, the two characteristic redox pairs for spinel lithium manganese oxide in the 4 V region could be detected, indicating that the film was well-crystallized and de-/intercalation processes were reversible. Raman post-analysis of a cycled cathode showed that the spinel-like structure was preserved within the cycling process but mechanical degradation effects such as film cracking were observed via scanning electron microscopy. Typical features for the formation of an additional surface reaction layer could be detected using X-ray photoelectron spectroscopy.

Effects of electrochemical-deposition method and microstructure on the capacitive characteristics of nano-sized manganese oxide

International Nuclear Information System (INIS)

Shinomiya, Takuya; Gupta, Vinay; Miura, Norio

2006-01-01

The amorphous nano-structured manganese oxide was electrochemically deposited onto a stainless-steel electrode. The structure and surface morphology of the obtained manganese oxide were studied by means of X-ray diffraction analysis and scanning electron microscopy. The capacitive characteristics of the manganese oxide electrodes were investigated by means of cyclic voltammetry and constant current charge-discharge cycling. The morphological and capacitive characteristics of the hydrous manganese oxide was found to be strongly influenced by the electrochemical deposition conditions. The highest specific capacitance value of ca. 410 F g -1 and the specific power of ca. 54 kW kg -1 were obtained at 400 mV s -1 sweep rate of potentiodynamic deposition condition. The cyclic-life data showed that the specific capacitance was highly stable up to 10,000 cycles examined. This suggests the excellent cyclic stability of the obtained amorphous hydrous manganese oxide for supercapacitor application

Effects of electrochemical-deposition method and microstructure on the capacitive characteristics of nano-sized manganese oxide

Energy Technology Data Exchange (ETDEWEB)

Shinomiya, Takuya; Gupta, Vinay; Miura, Norio [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

2006-06-01

The amorphous nano-structured manganese oxide was electrochemically deposited onto a stainless-steel electrode. The structure and surface morphology of the obtained manganese oxide were studied by means of X-ray diffraction analysis and scanning electron microscopy. The capacitive characteristics of the manganese oxide electrodes were investigated by means of cyclic voltammetry and constant current charge-discharge cycling. The morphological and capacitive characteristics of the hydrous manganese oxide was found to be strongly influenced by the electrochemical deposition conditions. The highest specific capacitance value of ca. 410Fg{sup -1} and the specific power of ca. 54kWkg{sup -1} were obtained at 400mVs{sup -1} sweep rate of potentiodynamic deposition condition. The cyclic-life data showed that the specific capacitance was highly stable up to 10,000 cycles examined. This suggests the excellent cyclic stability of the obtained amorphous hydrous manganese oxide for supercapacitor application. (author)

Manganese Deposits in the Artillery Mountains Region, Mohave County, Arizona

Science.gov (United States)

Lasky, S.G.; Webber, B.N.

1944-01-01

The manganese deposits of the Artillery Mountains region lie within an area of about 25 square miles between the Artillery and Rawhide Mountains, on the west side of the Bill Williams River in west-central Arizona. The richest croppings are on the northeast side of this area, among the foothills of the Artillery Mountains. They are 6 to 10 miles from Alamo. The nearest shipping points are Congress, about 50 miles to the east, and Aguila, about 50 miles to the southeast. The principal manganese deposits are part of a sequence of alluvial fan and playa material, probably of early Pliocene age, which were laid down in a fault basin. They are overlain by later Pliocene (?) basalt flows and sediments and by Quaternary basalt and alluvium. The Pliocene (?) rocks are folded into a shallow composite S1ncline ttat occupies the valley between the Artillery and Rawhide Mountains, and the folded rocks along either side of the valley, together with the overlying Quaternary basalt, are broken by faults that have produced a group of horsts, grabens, and step-fault blocks. The manganiferous beds, lie at two zones, 750 to 1,000 feet apart stratigraphically, each of which is locally as much as 300 to 400 feet thick. The main, or upper, zone contains three kinds of ore - sandstone ore, clay ore, and 'hard' ore. The sandstone and clay ores differ from the associated barren sandstone and clay, with which they are interlayered and into which they grade, primarily in containing a variable proportion of amorphous manganese oxides, besides iron oxides and clayey material such as are present in the barren beds. The 'hard' ore is sandstone that has been impregnated with opal and calcite and in which the original amorphous manganese oxides have been largely converted to psilomelane and manganite. The average manganese content of the sandstone and clay ores is between 3 and 4 percent and that of the 'hard' ore is between 6 and 7 percent. The ore contains an average of 3 percent of iron, 0

Exploiting a Simple Method for the Determination of Manganese in Polyethylene Lined Tubing for Petroleum and Natural Gas Industries

Directory of Open Access Journals (Sweden)

Shao Xiaodong

2018-01-01

Full Text Available The polyethylene lined tubing is the key to enabling the industry to meet some of the energy security challenges that nations face today. It is well known that manganese is an important element in polyethylene lined tubing. In this paper, a simple spectrophotometric method was described for the determination of manganese in polyethylene lined tubing. The method was based on the oxidation-reduction reaction between ammonium persulfate and manganese(II producing manganese(VII in the presence of silver nitrate as a catalyst. The characteristic wavelength of maximum absorption of manganese(VII was obtained locating at 530 nm. Under the optimum reaction conditions the absorption value was proportional to the concentration of manganese in the range of 0.2%~1.9% (R2 = 0.9997, and the relative standard deviation was less than 3.0% (n=5. The proposed method was applied successfully to determine manganese in polyethylene lined tubing real samples.

Development of manganese toxicity in pasture legumes under extreme climatic conditions. [Trifolium subterraneum; Medicago sativa; Brassica campestris

Energy Technology Data Exchange (ETDEWEB)

Siman, A; Cradock, F W; Hudson, A W

1974-08-01

Manganese levels and pH in soil were measured on limed and unlimed plots at bi-monthly intervals for two years at five field sites with lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) and related to rainfall and temperature. Pot experiments with lucerne, subterranean clover and rape (Brassica campestris) were used to confirm the results of the field experiments. Manganese toxicity developed in lucerne and subterranean clover under waterlogged conditions after heavy rain on the slightly acid soils (pH 4.7-5.5). Lucerne also showed manganese toxicity on the same soils in summer after extended hot, dry conditions. The maximum available manganese was 210 ..mu..g/g in the waterlogged soil (0-15 cm) the 128 ..mu..g/g in the heat affected soil. Lime treatment of 2240 kg/ha reduced the maximum available manganese to 148 ..mu..g/g in waterlogged plots and to 47 ..mu..g/g in the heat affected plots but failed to correct manganese toxicity. However, lime corrected toxicity symptoms under less severe conditions. In the pot experiments, available manganese reached 270 ..mu..g/g after 2 weeks artificial waterlogging and 68 ..mu..g/g after 2 weeks dry heat exposure. 12 references, 4 figures, 3 tables.

Sol-gel preparation of cobalt manganese mixed oxides for their use as electrode materials in lithium cells

International Nuclear Information System (INIS)

Lavela, P.; Tirado, J.L.; Vidal-Abarca, C.

2007-01-01

An ethanol dehydration procedure has been used to precipitate gel-like citrate precursors containing cobalt and manganese transition metal ions. Further annealing led to the Mn x Co 3-x O 4 spinel oxide series (x: 1, 1.5, 2, 3). Annealing temperature and treatment time were also evaluated to optimize the performance of the oxides as active electrode materials in lithium cells. The manganese-cobalt mixed oxides obtained by this procedure were cubic or tetragonal phases depending on the cobalt content. SEM images showed spherical macroporous aggregates for MnCo 2 O 4 and hollow spheres for manganese oxides. The galvanostatic cycling of lithium cells assembled with these materials demonstrated a simultaneous reduction of cobalt and manganese during the first discharge and separation of cobalt- and manganese-based products on further cycling. As compared with binary manganese oxides, a notorious electrochemical improvement was observed in the mixed oxides. This behavior is a consequence of the synergistic effect of both transition metal elements, associated with the in-situ formation of a nanocomposite electrode material when cobalt is introduced in the manganese oxide composition. Values higher than 400 mAh/g were sustained after 50 cycles for MnCo 2 O 4

Biostimulation strategies to enhance manganese removal in drinking water biofilters

DEFF Research Database (Denmark)

Breda, Inês Lousinha Ribeiro; Ramsay, Loren; Søborg, Ditte

to national drinking water criteria. The period during which virgin filter media matures into a fully functional biofilter is designated as the start-up period. The duration of a start-up for efficient manganese removal varies from weeks to more than a year. The aim of this study was to investigate...... growth and activity of specific bacteria. Biostimulation of virgin media to enhance initial manganese removal using different amendments strategies is possible especially in the early stages of filter development whereas autocatalytic processes appear to become dominant with time. The complex...

High levels of hair manganese in children living in the vicinity of a ferro-manganese alloy production plant.

Science.gov (United States)

Menezes-Filho, José A; Paes, Ciro R; Pontes, Angela M de C; Moreira, Josino C; Sarcinelli, Paula N; Mergler, Donna

2009-11-01

Manganese (Mn) is an essential element, but an effective toxic at high concentrations. While there is an extensive literature on occupational exposure, few studies have examined adults and children living near important sources of airborne Mn. The objective of this study was to analyze hair Mn of children living in the vicinity of a ferro-manganese alloy production plant in the Great Salvador region, State of Bahia, Brazil and examine factors that influence this bioindicator of exposure. We examined 109 children in the age range of 1-10 years, living near the plant. Four separate housing areas were identified a priori on the bases of proximity to the emission sources and downwind location. A non-exposed group (n=43) of similar socio-economic status was also evaluated. Mn hair (MnH) concentration was measured by graphite atomic absorption spectrometry (GFAAS). Possible confounding hematological parameters were also assessed. Mean MnH concentration was 15.20 microg/g (1.10-95.50 microg/g) for the exposed children and 1.37 microg/g (0.39-5.58 microg/g) for the non-exposed. For the former, MnH concentrations were 7.95+/-1.40 microg/g (farthest from the plant), 11.81+/-1.11 microg/g (mid-region), 34.43+/-8.66 microg/g (closest to the plant) and 34.22+/-9.15 microg/g (directly downwind). Multiple regression analysis on log transformed MnH concentrations for the exposed children derived a model that explained 36.8% of the variability. In order of importance, area of children's residence, gender (girls>boys) and time of mother's residence in the area at the birth of the child, were significantly associated with MnH. Post hoc analyses indicated two groupings for exposure areas, with those living closest to and downwind of the plant displaying higher MnH concentrations compared to the others. The contribution of the time the mother lived in the community prior to the child's birth to the children's current MnH suggests that in utero exposure may play a role. A study of

Manganese and iron geochemistry in sediments underlying the redox-stratified Fayetteville Green Lake

Science.gov (United States)

Herndon, Elizabeth M.; Havig, Jeff R.; Singer, David M.; McCormick, Michael L.; Kump, Lee R.

2018-06-01

Manganese and iron are redox-sensitive elements that yield clues about biogeochemistry and redox conditions both in modern environments and in the geologic past. Here, we investigated Mn and Fe-bearing minerals preserved in basin sediments underlying Fayetteville Green Lake, a redox-stratified lake that serves as a geochemical analogue for Paleoproterozoic oceans. Synchrotron-source microprobe techniques (μXRF, μXANES, and μXRD) and bulk geochemical analyses were used to examine the microscale distribution and speciation of Mn, Fe, and S as a function of depth in the top 48 cm of anoxic lake sediments. Manganese was primarily associated with calcite grains as a manganese-rich carbonate that precipitated in the chemocline of the water column and settled through the euxinic basin to collect in lake sediments. Iron was preserved in framboidal iron sulfides that precipitated in euxinic bottom waters and underwent transformation to pyrite and marcasite in the sediments. Previous studies attribute the formation of manganese-rich carbonates to the diagenetic alteration of manganese oxides deposited in basins underlying oxygenated water. Our study challenges this paradigm by providing evidence that Mn-bearing carbonates form in the water column and accumulate in sediments below anoxic waters. Consequently, manganoan carbonates preserved in the rock record do not necessarily denote the presence of oxygenated bottom waters in ocean basins.

Use of hydrous titanium dioxide as potential sorbent for the removal of manganese from water

Directory of Open Access Journals (Sweden)

Ramakrishnan Kamaraj

2014-12-01

Full Text Available This research article deals with an electrosynthesis of hydrous titanium dioxide by anodic dissolution of titanium sacrificial anodes and their application for the adsorption of manganese from aqueous solution. Titanium sheet was used as the sacrificial anode and galvanized iron sheet was used as the cathode. The optimization of different experimental parameters like initial ion concentration, current density, pH, temperature, etc., on the removal efficiency of manganese was carried out. The maximum removal efficiency of 97.55 % was achieved at a current density of 0.08 A dm-2 and pH of 7.0. The Langmuir, Freundlich and Redlich Peterson isotherm models were applied to describe the equilibrium isotherms and the isotherm constants were determined. The adsorption of manganese preferably followed the Langmuir adsorption isotherm. The adsorption kinetics was modelled by first- and second- order rate models and the adsorption kinetic studies showed that the adsorption of manganese was best described using the second-order kinetic model. Thermodynamic parameters indicate that the adsorption of manganese on hydrous titanium dioxide was feasible, spontaneous and exothermic.

Removal of Iron and Manganese Using Cascade Aerator and Limestone Roughing Filter

Directory of Open Access Journals (Sweden)

Mohd Sanusi Azrin

2016-01-01

Full Text Available Combination between oxidation and filtration can be used for removing iron and manganese from groundwater especially when the concentrations of these metals were high. This study focused on the effectiveness of the cascade aerator and the size of the limestone filter media to remove iron and manganese from groundwater. Water samples used for this study were collected from orphanage home, Rumah Nur Kasih, Taiping. Universiti Sains Malaysia (USM has provided a tube well of 15 m depth and 150 mm diameter for the orphanage home. However, the water cannot be used for domestic consumption due to high amount of iron and manganese at 6.48 and 1.9 mg/L which exceeded the drinking water standard of 0.3 and 0.1 mg/L respectively. Using laboratory physical model, the study has shown that the removals of iron and manganese have reduce the concentration until 0.17 and 0.2 mg/L respectively. Thus, the results from this study which utilize cascade aerator and limestone roughing filter could be implemented on site for the community to use the ground water for domestic purposes.

Arsenic, chromium, copper, iron, manganese, lead, selenium and ...

African Journals Online (AJOL)

Arsenic, chromium, copper, iron, manganese, lead, selenium and zinc in the tissues of the largemouth yellowfish, Labeobarbus kimberleyensis (Gilchrist and Thompson, 1913), from the Vaal Dam, South Africa, and associated consumption risks.

A new manganese-based oral contrast agent (CMC-001) for liver MRI. Pharmacological and pharmaceutical aspects

International Nuclear Information System (INIS)

Joergensen, Jan Troest; Rief, Matthias; Wagner, Moritz; Brismar, Torkel B.; Albiin, Nils

2012-01-01

Manganese is one of the most abundant metals on earth and is found as a component of more than 100 different minerals. Besides being an essential trace element in relation to the metabolic processes in the body, manganese is also a paramagnetic metal that possesses similar characteristics to gadolinium with regards to T1-weighted (T1-w) magnetic resonance imaging (MRI). Manganese, in the form of manganese (II) chloride tetrahydrate, is the active substance in a new targeted oral contrast agent, currently known as CMC-001, indicated for hepatobiliary MRI. Under physiological circumstances manganese is poorly absorbed from the intestine after oral intake, but by the use of specific absorption promoters, L-alanine and vitamin D3, it is possible to obtain a sufficiently high concentration in the liver in order to achieve a significant signal enhancing effect. In the liver manganese is exposed to a very high first-pass effect, up to 98 %, which prevents the metal from reaching the systemic circulation, thereby reducing the number of systemic side-effects. Manganese is one of the least toxic trace elements, and due to its favorable safety profile it may be an attractive alternative to gadolinium-based contrast agents for patients undergoing an MRI evaluation for liver metastases in the future. In this review the basic pharmacological and pharmaceutical aspects of this new targeted oral hepatobiliary specific contrast agent will be discussed

Calcium manganese oxides as oxygen evolution catalysts: O2 formation pathways indicated by 18O-labelling studies.

Science.gov (United States)

Shevela, Dmitriy; Koroidov, Sergey; Najafpour, M Mahdi; Messinger, Johannes; Kurz, Philipp

2011-05-02

Oxygen evolution catalysed by calcium manganese and manganese-only oxides was studied in (18)O-enriched water. Using membrane-inlet mass spectrometry, we monitored the formation of the different O(2) isotopologues (16)O(2), (16)O(18)O and (18)O(2) in such reactions simultaneously with good time resolution. From the analysis of the data, we conclude that entirely different pathways of dioxygen formation catalysis exist for reactions involving hydrogen peroxide (H(2)O(2)), hydrogen persulfate (HSO(5)(-)) or single-electron oxidants such as Ce(IV) and [Ru(III) (bipy)(3)](3+) . Like the studied oxide catalysts, the active sites of manganese catalase and the oxygen-evolving complex (OEC) of photosystem II (PSII) consist of μ-oxido manganese or μ-oxido calcium manganese sites. The studied processes show very similar (18)O-labelling behaviour to the natural enzymes and are therefore interesting model systems for in vivo oxygen formation by manganese metalloenzymes such as PSII. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Calcium manganese(IV) oxides: biomimetic and efficient catalysts for water oxidation.

Science.gov (United States)

Najafpour, Mohammad Mahdi; Pashaei, Babak; Nayeri, Sara

2012-04-28

CaMnO(3) and Ca(2)Mn(3)O(8) were synthesized and characterized by SEM, XRD, FTIR and BET. Both oxides showed oxygen evolution activity in the presence of oxone, cerium(IV) ammonium nitrate and H(2)O(2). Oxygen evolution from water during irradiation with visible light (λ > 400 nm) was also observed upon adding these manganese oxides to an aqueous solution containing tris(2,2'-bipyridyl) ruthenium(II), as photosensitizer, and chloro pentaammine cobalt(III) chloride, as electron acceptor, in an acetate buffer. The amounts of dissolved manganese and calcium from CaMnO(3) and Ca(2)Mn(3)O(8) in the oxygen evolving reactions were reported and compared with other (calcium) manganese oxides. Proposed mechanisms of oxygen evolution and proposed roles for the calcium ions are also considered. This journal is © The Royal Society of Chemistry 2012

Effect of manganese and zinc on the growth of Anacystis nidulans

Energy Technology Data Exchange (ETDEWEB)

Lee, L.H.; Lustigman, B.; Dandorf, D. (Montclair State College, Upper Montclair, NJ (United States))

1994-07-01

Anacystis nidulans is a unicellular member of the cyanobacteria, one of the largest groups of the Kingdom Monera. It is similar to other bacteria in the structure and chemistry of the cell wall, and its cell division and genetic recombination. Photoautotrophy is the main mode of nutrition and the photosynthetic apparatus is similar to that of other cyanobacteria. Cyanobacteria are excellent organisms to serve as environmental pollution indicators for the investigation of a wide variety of biological problems. There have been several studies on the effects of heavy metals on A. nidulans. Some of these elements, such as manganese, are known to be essential nutrients for cyanobacteria. Others, such as cadmium, are not known to be necessary for normal growth and metabolism. Large amounts of either essential or non-essential elements can be toxic. Manganese and zinc are essential elements for all living organisms. Manganese is a cofactor for a number of different enzymatic reactions particularly those involved in phosphorylation. Iron deficiency induced by a number of metals, cobalt and manganese in particular, inhibit chlorophyll biosynthesis. Zinc deficiency affects early mitotic events and the cells are large and aberrant in appearance. Light is essential for cells to take in zinc. As an industrial contaminant, zinc has been found to block photosynthesis by causing structural damage to the photosynthetic apparatus. In the presence of various pH ranges, high zinc concentrations can be associated with low pH. It has been indicated that pH value and EDTA (Ethylene Diamine Tetraacetic Acid) have an influence on the effect of some metals. The purpose of this study was to determine the effect of manganese and zinc on the growth of Anacystis nidulans, with and without EDTA.

Aging promotes todorokite formation from layered manganese oxide at near-surface conditions

Energy Technology Data Exchange (ETDEWEB)

Cui, Haojie [Chinese Academy of Sciences, Xiamen (China). Key Lab. of Urban Environment and Health; Huazhong Agricultural Univ., Ministry of Agriculture, Wuhan (China). Key Lab. of Subtropical Agricultural Resources and Environment; Liu, Fan; Feng, Xionghan; Tan, Wenfeng [Huazhong Agricultural Univ., Ministry of Agriculture, Wuhan (China). Key Lab. of Subtropical Agricultural Resources and Environment; Wang, Ming Kuang [National Taiwan Univ., Taipei (China). Dept. of Agricultural Chemistry

2010-12-15

Todorokite is one common manganese oxide in soils and sediments and is commonly formed from layered Na-buserite. Aging processes can alter the physicochemical properties of freshly formed Na-buserite in natural environments. However, it is not clear whether and how aging affects the formation of todorokites. In the present paper, Na-buserite with aging treatment was employed to prepare todorokite at atmospheric pressure to investigate the effects of aging treatment of Na-buserite on the formation of todorokite. Four aged Na-buserite samples, which are produced through oxidation of Mn{sup 2+} in concentrated NaOH medium by O{sub 2} with aging for 3, 6, 9, and 12 months, were employed to investigate the effects of aging processes on the transformation from Na-buserite to todorokite by Mg{sup 2+}-templating reaction at atmospheric pressure. The manganese oxides were examined using X-ray diffraction (XRD), elemental analysis, determinations of the average manganese oxidation number, infrared spectroscopy (IR), and transmission electron microscopy (TEM). The XRD, IR, and elemental analyses indicate that aging treatment can alter the substructure of the freshly synthesized Na-buserite. During the aging process, some of the Mn(III) may migrate into the interlayer region or disproportionate to form Mn{sup 2+} and Mn{sup 4+} from the layer of Na-buserite and the concomitant formation of layer vacancies. The interlayer Mn{sup 3+} or Mn{sup 2+} occupied above or below the layer vacancy sites and become corner-sharing octahedral. XRD analyses and TEM clearly show that the transformation from Na-buserite to todorokite was promoted by aging treatments. The alterations of substructure of aged Na-buserites can promote the rearrangement of manganese to construct a tunnel structure during the transformation from layered manganese oxides to tunnel-structure todorokite at atmospheric pressure. The transformation from Na-buserite to todorokite was promoted by aging treatments at

Barium and manganese-doped zinc silicate rods prepared by mesoporous template route and their luminescence property

Science.gov (United States)

Dang, Lingyan; Tian, Chen; Zhao, Shifeng; Lu, Qingshan

2018-06-01

Barium and manganese-doped zinc silicates was prepared under hydrothermal treatment by mesoporous template route employing mesoporous silica as an active template. The sample displays a rod-like morphology with a mean diameter of ∼40 nm and a mean length of ∼450 nm, which inherits the characteristics of mesoporous silica. The individual rods show single crystalline and assemble into bundle-like hierarchical structure along the channels of the mesoporous silica. When barium ions together with manganese ions are co-doped in zinc silicate, the green emission corresponding to manganese ions display a significant enhancement, especially for the sample with the barium doping concentration of 0.08, which indicates that an energy transfer from barium to manganese ions takes place. With further increasing barium concentration from 0.08 to 0.10, the recombination between the defects related to barium and the excitation states of the manganese dominates accompanying non-radiative transitions which can reduce the emission efficiency.

Biodiesel production using calcium manganese oxide as catalyst and different raw materials

International Nuclear Information System (INIS)

Dias, Joana Maia; Conceição Machado Alvim-Ferraz, Maria; Fonseca Almeida, Manuel; Méndez Díaz, José Diego; Sánchez Polo, Manuel; Rivera Utrilla, José

2013-01-01

Highlights: ► Biodiesel production using a calcium manganese oxide catalyst was studied. ► The active specie was Ca 0.9 Mn 0.1 O and its deactivation occurred by hydration. ► The studied catalyst presented lower activation temperature than CaO. ► Biodiesel production and quality using different raw materials is reported. ► Compared to the conventional process, biodiesel water content improved. - Abstract: The use of heterogeneous catalysts for biodiesel production aims to simplify the production process as well as to reduce purification costs and related environmental impacts. Calcium manganese oxide was recently identified by the authors as an interesting heterogeneous catalyst for biodiesel production from animal fat; however, the difference between this and other catalysts, the catalyst activation/deactivation mechanisms, its behaviour in the synthesis using different raw materials as well as the impacts of its use on product quality remained unclear. Therefore, the present work: (i) compared biodiesel production using calcium manganese oxide and other catalysts (CaO and NaOH); (ii) studied the reasons leading to activation/deactivation of the heterogeneous catalyst; (iii) analysed biodiesel heterogeneous synthesis using calcium manganese oxide and different raw materials (lard, waste frying oil and a mixture); and (iv) evaluated raw material and catalyst impact on the product quality. Considering the use of different catalysts, the results showed that, after 8 h of reaction, product purity was similar using the different catalysts, being 92.5 wt.% using both NaOH and calcium manganese oxide and 93.8 wt.% using CaO. The active species of the heterogeneous catalysts were CaO, in the case of calcinated calcium carbonate, and Ca 0.9 Mn 0.1 O, in the case of calcinated calcium manganese oxide. Because the deactivating species were different for both catalysts, the calcium manganese oxide required lower activation temperature, which should be an advantage

Crystallization and spectroscopic studies of manganese malonate

Indian Academy of Sciences (India)

Administrator

... and its esters are important intermediates in syntheses of vitamins B1 and B6, barbitu- ... been a subject of interest because of the importance of such interactions in a ... The d-values of the Bragg peaks in the XRD. Figure 1. (a) Manganese ...

Manganese-Enhanced MRI for Preclinical Evaluation of Retinal Degeneration Treatments.

Science.gov (United States)

Schur, Rebecca M; Sheng, Li; Sahu, Bhubanananda; Yu, Guanping; Gao, Songqi; Yu, Xin; Maeda, Akiko; Palczewski, Krzysztof; Lu, Zheng-Rong

2015-07-01

Apply manganese-enhanced magnetic resonance imaging (MEMRI) to assess ion channel activity and structure of retinas from mice subject to light-induced retinal degeneration treated with prophylactic agents. Abca4(-/-)Rdh8(-/-) double knockout mice with and without prophylactic retinylamine (Ret-NH2) treatment were illuminated with strong light. Manganese-enhanced MRI was used to image the retina 2 hours after intravitreous injection of MnCl2 into one eye. Contrast-enhanced MRIs of the retina and vitreous humor in each experimental group were assessed and correlated with the treatment. Findings were compared with standard structural and functional assessments of the retina by optical coherence tomography (OCT), histology, and electroretinography (ERG). Manganese-enhanced MRI contrast in the retina was high in nonilluminated and illuminated Ret-NH2-treated mice, whereas no enhancement was evident in the retina of the light-illuminated mice without Ret-NH2 treatment (P treatment based on the measurement of ion channel activity. This approach could be used as a complementary tool in preclinical development of new prophylactic therapies for retinopathies.

The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

International Nuclear Information System (INIS)

Vatolin, N.A.; Volkova, P.I.; Sapozhnikova, T.V.; Ovchinnikova, L.A.

1988-01-01

The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

Hybrid ternary rice paper-manganese oxide-carbon nanotube nanocomposites for flexible supercapacitors

Science.gov (United States)

Jiang, Wenchao; Zhang, Kaixi; Wei, Li; Yu, Dingshan; Wei, Jun; Chen, Yuan

2013-10-01

Modern portable electronic devices create a strong demand for flexible energy storage devices. Paper based nanocomposites are attractive as sustainable materials for such applications. Here, we directly explored the hydroxyl chemistry of cellulose fibers to synthesize hybrid ternary nanocomposites, comprised of rice paper, single-walled carbon nanotubes (SWCNTs) and manganese oxide nanoparticles. The functional groups on cellulose fibers can react with adsorbed permanganate ions, resulting in uniform deposition of manganese oxide nanoparticles. SWCNTs coated on top of manganese oxide nanoparticles form a highly conductive network connecting individual manganese oxide particles. By using the hybrid ternary composites as electrodes, the assembled two-electrode supercapacitors demonstrated high capacitance (260.2 F g-1), energy (9.0 W h kg-1), power (59.7 kW kg-1), and cycle stability (12% drop after 3000 cycles). In addition, the nanocomposites show good strength and excellent mechanical flexibility, and their capacitance shows negligible changes after bending more than 100 times. These findings suggest that opportunities exist to further explore the rich chemistry of cellulose fibers for innovative energy applications.Modern portable electronic devices create a strong demand for flexible energy storage devices. Paper based nanocomposites are attractive as sustainable materials for such applications. Here, we directly explored the hydroxyl chemistry of cellulose fibers to synthesize hybrid ternary nanocomposites, comprised of rice paper, single-walled carbon nanotubes (SWCNTs) and manganese oxide nanoparticles. The functional groups on cellulose fibers can react with adsorbed permanganate ions, resulting in uniform deposition of manganese oxide nanoparticles. SWCNTs coated on top of manganese oxide nanoparticles form a highly conductive network connecting individual manganese oxide particles. By using the hybrid ternary composites as electrodes, the assembled two

Thermodynamics of manganese oxides: Sodium, potassium, and calcium birnessite and cryptomelane

Science.gov (United States)

Birkner, Nancy; Navrotsky, Alexandra

2017-01-01

Manganese oxides with layer and tunnel structures occur widely in nature and inspire technological applications. Having variable compositions, these structures often are found as small particles (nanophases). This study explores, using experimental thermochemistry, the role of composition, oxidation state, structure, and surface energy in the their thermodynamic stability. The measured surface energies of cryptomelane, sodium birnessite, potassium birnessite and calcium birnessite are all significantly lower than those of binary manganese oxides (Mn3O4, Mn2O3, and MnO2), consistent with added stabilization of the layer and tunnel structures at the nanoscale. Surface energies generally decrease with decreasing average manganese oxidation state. A stabilizing enthalpy contribution arises from increasing counter-cation content. The formation of cryptomelane from birnessite in contact with aqueous solution is favored by the removal of ions from the layered phase. At large surface area, surface-energy differences make cryptomelane formation thermodynamically less favorable than birnessite formation. In contrast, at small to moderate surface areas, bulk thermodynamics and the energetics of the aqueous phase drive cryptomelane formation from birnessite, perhaps aided by oxidation-state differences. Transformation among birnessite phases of increasing surface area favors compositions with lower surface energy. These quantitative thermodynamic findings explain and support qualitative observations of phase-transformation patterns gathered from natural and synthetic manganese oxides. PMID:28130549

Influence of limestone doses in the Manganese absorption by Brachiaria decumbens

International Nuclear Information System (INIS)

Armelin, Maria Jose A.; Fulas, Paulo M.M.; Saiki, Mitiko; Primavesi, Odo; Primavesi, Ana C.

2005-01-01

To restore a degraded pasture of Brachiaria decumbens, located in Sao Carlos - SP, Southeastern Brazil, under tropical climate, an experiment was carried out to study the influence of different methods of the limestone doses application on manganese absorption by the aboveground part of the forage, during 3 years of treatment. The experimental design was randomized block, with 6 replications and 8 treatments. The 100m 2 blocks were established in the pasture. Each block received a sequence of limestone doses (0, 1, 2, 4, and 8 t/ha) applied on soil surface with NK and, 2 t/ha applied on soil surface with plus one annual application of 1t/ha and NK, 4t/ha buried in the soil with NK, 4t/ha applied on soil surface without NK. Forages samples were collected 14 cm above soil surface. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine manganese content. The statistical analysis showed some significant variations of this element absorption by the plant with regard to the treatments, but anything that could compromise the mineral nutrition of forage. Moreover, the quality of forage for the animal feeding showed suitable agreement to manganese requirement. INAA showed that it can be an alternative option for agronomical researches that require the knowledge of the manganese concentration. (author)

Adhesive wear of iron chromium nickel silicon manganese molybdenum niobium alloys with duplex structure

International Nuclear Information System (INIS)

Lugscheider, E.; Deppe, E.; Ambroziak, A.; Melzer, A.

1991-01-01

Iron nickel chromium manganese silicon and iron chromium nickel manganese silicon molybdenum niobium alloys have a so-called duplex structure in a wide concentration range. This causes an excellent resistance to wear superior in the case of adhesive stress with optimized concentrations of manganese, silicon, molybdenum and niobium. The materials can be used for welded armouring structures wherever cobalt and boron-containing alloy systems are not permissible, e.g. in nuclear science. Within the framework of pre-investigations for manufacturing of filling wire electrodes, cast test pieces were set up with duplex structure, and their wear behavior was examined. (orig.) [de

Reuse of Anode Slime Generated by the Zinc Industry to Obtain a Liquor for Manufacturing Electrolytic Manganese

Science.gov (United States)

Ayala, J.; Fernández, B.

2013-08-01

A hydrometallurgical process is proposed in this article to recover manganese from a zinc electrowinning residue. The article describes the digestion-leaching experiments, precipitation, and electrowinning assays to recover Mn from this residue. Anode slime is treated with sulfuric acidic in a furnace within a temperature range of 400-450°C, leached with water, and then filtered. The results show that the dissolution of manganese increases with increasing temperature in the digestion step. The recovery yield of manganese was higher than 90%. As manganese electrolysis requires an electrolyte free of Zn, Ni, Co, and Cu pollutants, the sulfuric acid liquor needs a purification step. Na2S is used to remove pollutants. The results obtained in this study have shown that the proposed process for the recovery of manganese from this type of residue is technically viable.

Selective Method for the Determination of Manganese in End-fitting of Spoolable Reinforced Plastic Line Pipe for Petroleum Industries

Science.gov (United States)

Shao, Xiaodong; Zhang, Dongna; Li, Houbu; Cai, Xuehua

2017-10-01

The fact that spoolable reinforced plastic line pipe is more flexible and spoolable than steel, and is also much lighter, means that it can becarried and deployedfrom smaller vessels and managed more easily. It was well known that manganese is an important element in end-fitting of spoolable reinforced plastic line pipe. In this paper, a simple spectrophotometric method was described for the determination of manganese in end-fitting of spoolable reinforced plastic line pipe. The method was based on the oxidation-reduction reaction between ammonium persulfate and manganese(II) producing manganese(VII) in the presence of silver nitrate as a catalyst. The characteristic wavelength of maximum absorption of manganese(VII) was obtained locating at 530 nm. Under the optimum reaction conditions the absorption value was proportional to the concentration of manganese in the range of 0.50%˜1.80% (R2 = 0.9997), and the relative standard deviation was less than 3.0% (n=5). The proposed method was applied successfully to determine manganese in end-fitting of spoolable reinforced plastic line pipe samples.

Reuse of worn-out medicaments with adsorbent properties for the removal of manganese

International Nuclear Information System (INIS)

Millan C, E.

2005-01-01

The current investigations on the treatment of worn-out medicaments in Mexico, reveal that most of these treatments are carried out with the purpose to reduce the packing and diminish the toxic level that presents each one of those medicaments. That it reach to reuse of them is their packing material and/or their cover. Once treated, the worn-out medicaments move to a sanitary filler. With relationship to the investigation works that have been carried out for the manganese removal in solution, they show a great number of materials that they are used for this end, as well as the parameters that influence in the process, such as the concentration of the element, the solution type in that is content and the pH. However, it is not mentioned in none of them the reuse of the worn-out medicaments (Talcid and Melox), as adsorbent materials for the removal of metals from the water. To carry out the present investigation they were selected therefore, to the one Talcid and the Melox because its present adsorbent properties, with the purpose to remove the manganese like water pollutant. Once that the worn-out medicaments were obtained, they put on in contact with different organic solvents, to obtain the active principle, due to the pharmaceutical presentation of the two medicaments that was obtained was in suspension. The active principles of the two medicaments were characterized by means of high vacuum scanning electron microscopy (SEM), elementary microanalysis (EDS) and X-ray diffraction (XRD). The experimental part consisted in putting in contact manganese solutions with the active principles of the worn-out medicaments, varying the time of contact and the concentration. The manganese quantification in the liquid phase carried out by means of atomic absorption spectroscopy (AAS). It was found that the kinetic model that better describes the sorption process of manganese in both worn-out medicaments (Talcid and Melox) it is that of pseudo second order. Those results of

Preparation of manganese-based perovskite nanoparticles using a ...

Indian Academy of Sciences (India)

Preparation of manganese-based perovskite nanoparticles using a reverse microemulsion method: ... ted much attention in various fields of medicine and pharma- cology such as .... In addition, the SAR value of sample was calculated through ...

Electrosynthesis of Biomimetic Manganese-Calcium Oxides for Water Oxidation Catalysis--Atomic Structure and Functionality.

Science.gov (United States)

González-Flores, Diego; Zaharieva, Ivelina; Heidkamp, Jonathan; Chernev, Petko; Martínez-Moreno, Elías; Pasquini, Chiara; Mohammadi, Mohammad Reza; Klingan, Katharina; Gernet, Ulrich; Fischer, Anna; Dau, Holger

2016-02-19

Water-oxidizing calcium-manganese oxides, which mimic the inorganic core of the biological catalyst, were synthesized and structurally characterized by X-ray absorption spectroscopy at the manganese and calcium K edges. The amorphous, birnesite-type oxides are obtained through a simple protocol that involves electrodeposition followed by active-site creation through annealing at moderate temperatures. Calcium ions are inessential, but tune the electrocatalytic properties. For increasing calcium/manganese molar ratios, both Tafel slopes and exchange current densities decrease gradually, resulting in optimal catalytic performance at calcium/manganese molar ratios of close to 10 %. Tracking UV/Vis absorption changes during electrochemical operation suggests that inactive oxides reach their highest, all-Mn(IV) oxidation state at comparably low electrode potentials. The ability to undergo redox transitions and the presence of a minor fraction of Mn(III) ions at catalytic potentials is identified as a prerequisite for catalytic activity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of routine MRI and 1H-MRS in evaluating the central neurological damages caused by occupational manganese exposure

International Nuclear Information System (INIS)

Li Xiangrong; Long Liling; Jiang Muliang

2010-01-01

Objective: MRI and MR hydrogen proton spectroscopy ( 1 H-MRS) were used to detect the abnormal signal and alteration of metabolites, in order to explore the efficacy of these method in evaluating the damages of central nervous system (CNS) induced by occupational manganese exposure. Methods: Eighteen workers exposed to manganese without any manganism symptoms, 12 workers with slightly chronic manganese poisoning, and 19 healthy workers were scanned using routine MRI sequence and 1 H-MRS. The blood manganese concentration was also collected for each subject. On cerebral axial T 1 WI, the signal intensities of ipsilateral globus pallidus and frontal white matter were measured in the visually brightest area (try to select the signal homogeneous region), and the globus pallidus index (PI) was then calculated. The 1 H-MRS data was calculated to get the values of the peak height of N-acetylaspartate (NAA), choline (Cho), inositol (mI) and creatine (Cr) and the ratios of NAA/Cr, Cho/Cr, and mL/Cr were also calculated. One way ANOVA was used to compare the values of PI, NAA/Cr, Cho/Cr, mI/Cr and MnB among the three groups, and the correlations between PI and the time span of manganese exposure or blood manganese concentration were analyzed by Pearson correlation analysis. Eight workers exposed to manganese were followed up one year, and their PI, NAA/Cr before and after follow-up were compared by t test. Results: Fourteen of 18 cases exposed to manganese without any manganism symptoms showed symmetrically high intensity signal on T 1 WI, while the T 2 WI were normal. No high signal intensity was obseerved on T 1 WI in any of the healthy workers or manganese poisoning workers. We found that the average PI in manganese exposed group (1.16 ± 0.09) was significantly higher (F=24.79,P=0.000) than those of the poisoning (1.05±0.07) and control groups (1.01±0.05). The blood manganese concentration in manganese exposed group, the poisoning group and the control group were (0

Adsorption of selenium by amorphous iron oxyhydroxide and manganese dioxide

Science.gov (United States)

Balistrieri, L.S.; Chao, T.T.

1990-01-01

This work compares and models the adsorption of selenium and other anions on a neutral to alkaline surface (amorphous iron oxyhydroxide) and an acidic surface (manganese dioxide). Selenium adsorption on these oxides is examined as a function of pH, particle concentration, oxidation state, and competing anion concentration in order to assess how these factors might influence the mobility of selenium in the environment. The data indicate that 1. 1) amorphous iron oxyhydroxide has a greater affinity for selenium than manganese dioxide, 2. 2) selenite [Se(IV)] adsorption increases with decreasing pH and increasing particle concentration and is stronger than selenate [Se(VI)] adsorption on both oxides, and 3. 3) selenate does not adsorb on manganese dioxide. The relative affinity of selenate and selenite for the oxides and the lack of adsorption of selenate on a strongly acidic surface suggests that selenate forms outer-sphere complexes while selenite forms inner-sphere complexes with the surfaces. The data also indicate that the competition sequence of other anions with respect to selenite adsorption at pH 7.0 is phosphate > silicate > molybdate > fluoride > sulfate on amorphous iron oxyhydroxide and molybdate ??? phosphate > silicate > fluoride > sulfate on manganese dioxide. The adsorption of phosphate, molybdate, and silicate on these oxides as a function of pH indicates that the competition sequences reflect the relative affinities of these anions for the surfaces. The Triple Layer surface complexation model is used to provide a quantitative description of these observations and to assess the importance of surface site heterogeneity on anion adsorption. The modeling results suggest that selenite forms binuclear, innersphere complexes with amorphous iron oxyhydroxide and monodentate, inner-sphere complexes with manganese dioxide and that selenate forms outer-sphere, monodentate complexes with amorphous iron oxyhydroxide. The heterogeneity of the oxide surface sites

Amorphous manganese-calcium oxides as a possible evolutionary origin for the CaMn₄ cluster in photosystem II.

Science.gov (United States)

Najafpour, Mohammad Mahdi

2011-06-01

In this paper a few calcium-manganese oxides and calcium-manganese minerals are studied as catalysts for water oxidation. The natural mineral marokite is also studied as a catalyst for water oxidation for the first time. Marokite is made up of edge-sharing Mn(3+) in a distorted octahedral environment and eight-coordinate Ca(2+) centered polyhedral layers. The structure is similar to recent models of the oxygen evolving complex in photosystem II. Thus, the oxygen evolving complex in photosystem II does not have an unusual structure and could be synthesized hydrothermally. Also in this paper, oxygen evolution is studied with marokite (CaMn₂O₄), pyrolusite (MnO₂) and compared with hollandite (Ba(0.2)Ca(0.15)K(0.3)Mn(6.9)Al(0.2)Si(0.3)O(16)), hausmannite (Mn₃O₄), Mn₂O₃.H₂O, Ca Mn₃O₆.H₂O, CaMn₄O₈.H₂O, CaMn₂O₄.H₂O and synthetic marokite (CaMn₂O₄). I propose that the origin of the oxygen evolving complex in photosystem II resulted from absorption of calcium and manganese ions that were precipitated together in the archean oceans by protocyanobacteria because of changing pH from ~5 to ~8-10. As reported in this paper, amorphous calcium-manganese oxides with different ratios of manganese and calcium are effective catalysts for water oxidation. The bond types and lengths of the calcium and manganese ions in the calcium-manganese oxides are directly comparable to those in the OEC. This primitive structure of these amorphous calcium-manganese compounds could be changed and modified by environmental groups (amino acids) to form the oxygen evolving complex in photosystem II.

Manganese oxidation and bacterial diversity on different filter media coatings during the start-up of drinking water biofilters

DEFF Research Database (Denmark)

Breda, I. L.; Ramsay, L.; Roslev, P.

2017-01-01

Manganese removal is a typical concern in drinking water production. Biofiltration may be used when treating groundwater sources but the onset of manganese removal in virgin biofilters can vary considerably. The aim of this study was to investigate the effect of different filter media on manganese...... by manganese oxide, while 48, 57 and 72 days were required by virgin quartz, calcium carbonate and polystyrene, respectively. The bacterial community was investigated using DAPI staining, quantitative polymerase chain reaction (qPCR), 16S rRNA gene pyrosequencing, and bacterial enrichments. Bacterial abundance...

Analysis of material flow in a utillzation technology of low grade manganese ore and sulphur coal complementary

Science.gov (United States)

Wang, Bo-Zhi; Deng, Biao; Su, Shi-Jun; Ding, Sang-Lan; Sun, Wei-Yi

2018-03-01

Electrolytic manganese is conventionally produced through low-grade manganese ore leaching in SO2, with the combustion of high sulfur coal. Subsequently the coal ash and manganese slag, produced by the combustion of high sulfur coal and preparation of electrolytic manganese, can be used as raw ingredients for the preparation of sulphoaluminate cement. In order to realize the `coal-electricity-sulfur-manganese-building material' system of complementary resource utilization, the conditions of material inflow and outflow in each process were determined using material flow analysis. The material flow models in each unit and process can be obtained by analyzed of material flow for new technology, and the input-output model could be obtained. Through the model, it is possible to obtain the quantity of all the input and output material in the condition of limiting the quantity of a substance. Taking one ton electrolytic manganese as a basis, the quantity of other input material and cements can be determined with the input-output model. The whole system had thusly achieved a cleaner production level. Therefore, the input-output model can be used for guidance in practical production.

Selective uptake of manganese in seawater by hybrid microcapsules

International Nuclear Information System (INIS)

Kuzumaki, Takenori; Yan, Wu; Mimura, Hitoshi; Niibori, Yuichi

2008-01-01

The selective separation and recovery of low concentrated elements in seawater are very important subjects for the advancement of environmental monitoring. Selective uptake of manganese from seawater was carried out by using two kinds of microcapsules (MCs) including activated carbon (AC) and insoluble tannin (T). The adsorbents, AC and T, having affinity for manganese, were enclosed into MCs (ACMS, TMC) by sol-gel method using matrices of biopolymer (calcium alginate gel polymer, CaALG). The uptake properties and selectivity of Mn 2+ (1 ppm) for MCs were examined by batch method. Relatively large uptake percentages of Mn 2+ above 80% were obtained within 1 h, and the uptake percentage above 80% was kept at pH 3-6. The uptake order was found to be T, AC, CaALG > ACMC, TMC. The uptake of Mn 2+ decreased with increasing Na + ion concentration. This tendency depends on the swelling property of CaALG; it tends to solate in the presence of highly concentrated Na + ions. The manganese ions were adsorbed on CaALG, ACMC and TMC from seawater containing 1,000 ppm Mn 2+ . ACMC and TMC had selectivity to Mn 2+ , and, especially, the matrices of CaALG also had an excellent uptake and selectivity properties. (author)

Characterisation of chemically lithiated heat-treated electrolytic manganese dioxide

International Nuclear Information System (INIS)

Dose, Wesley M.; Lehr, Joshua; Donne, Scott W.

2012-01-01

Highlights: ► Manganese oxides are a promising cathode material for lithium ion batteries. Here we examine the structural and morphological changes that occur upon reduction, and assess its impact on material performance. ► Upon reduction, MnO 2 transforms into LiMn 2 O 4 , which is subsequently reduced to Li 2 Mn 2 O 4 . ► Significant morphological changes occur, particularly to the material porosity. ► This transformation for MnO 2 has not been reported previously. -- Abstract: Heat treated manganese dioxide is partially lithiated using butyl-lithium to determine the changes in crystal structure, chemical composition and morphology upon reduction, as a means of simulating its discharge behaviour in a non-aqueous battery cathode. As reduction proceeds, and lithium ions are inserted into the heat treated electrolytic manganese dioxide (EMD) structure, the material undergoes a phase transition to LiMn 2 O 4 . This new phase is further reduced to Li 2 Mn 2 O 4 . Reduction initially results in a 56% decrease in the surface area of the material; however, at higher degrees of reduction a slight increase in this value is observed, as a consequence of the strain placed on the lattice through continued lithium insertion.

BUILDING MATERIALS AND PRODUCTS BASED ON SILICON MANGANESE SLAGS

Directory of Open Access Journals (Sweden)

BOLSHAKOV V. I.

2016-05-01

Full Text Available Raising of problem. Currently of particular relevance was given to the matter of introduction in manufacture of building materials and products, resource-saving techniques and technologies; integrated use of raw materials and materials that prevent or significantly reduce their harmful impact on the environment. This allows you to recycle hundreds of thousands of tons of the fiery liquid slags of silicon manganese and to develop effective structural materials that can replace metals, non-metallic building materials of natural origin, concretes, cast stone, plastics and refractories. Purpose. The study of the structure and properties of building materials and products from electric furnace slag of silicon manganese. Conclusion. Slags from the smelting of silicon manganese are classified as acidic. Their lime factor is in the range of 0.47–0.52. The composition of the slag located in the heterogeneous region SiO2 near the line of separation of cristobalite spread to the crystallization of wollastonite, according to the ternary system MnO-CaO-SiO2, which in consideration of their stability, allows the development of technology of building materials (gravel, sand, granulated slag, etc. and products (foundation blocks, road slabs, containers for transportation and storage of hazardous waste, and others.

Growth rate and chemical composition of a manganese nodule from the EEZ of Seychelles

Digital Repository Service at National Institute of Oceanography (India)

Banakar, V.K.; Borole, D.V.

mhe ferro-manganese nodule collected in EEZ of Seychelles yields a growth rate of 1.5 mm/10 6Y 230Th (ex)/ and 230Th (ex)/ 232Th activity ratio methods indicating very slow growth of ferro-manganese nodules. The Mn/Fe and U/Th ratios suggest...

The Efficiency of Iron and Manganese Removal from Groundwater Using Tower Aeration

Directory of Open Access Journals (Sweden)

Meghdad Pirsaheb

2012-09-01

Full Text Available Groundwaters passing through different layers of soil and due to its water properties and its high solubility, contain elements and minerals of material in the soil that sometimes can be dangerous for the health of consumers or at least undesirable in terms of cognitive beautiful. Iron and manganese are from constitutive of the soil and rocks of the Earth's surface. Water penetration through soil and rock can minerals such as these elements have dissolved and bring them into solution. The problems of iron and manganese in groundwater in domestic installations, commercial, industrial and refineries are created, and because much of the community water supply from underground water supplies will be removed where iron and manganese concentrations exceeded it is necessary. In this study Tower aeration system performance for the removal of iron and manganese from groundwater sources have been studied. In this research, pilot column aeration tower design, implementation and was established. This system made of PVC with a diameter and height 150 cm and 15 cm which was filled with flexible pipe parts. The initial pH=5, 7 and 9 and the initial concentration of Fe and Mn 2, 3 and 4 mg/l of the output system, sampling was done.

Facile synthesis of birnessite-type manganese oxide nanoparticles as supercapacitor electrode materials.

Science.gov (United States)

Liu, Lihu; Luo, Yao; Tan, Wenfeng; Zhang, Yashan; Liu, Fan; Qiu, Guohong

2016-11-15

Manganese oxides are environmentally benign supercapacitor electrode materials and, in particular, birnessite-type structure shows very promising electrochemical performance. In this work, nanostructured birnessite was facilely prepared by adding dropwise NH2OH·HCl to KMnO4 solution under ambient temperature and pressure. In order to fully exploit the potential of birnessite-type manganese oxide electrode materials, the effects of specific surface area, pore size, content of K(+), and manganese average oxidation state (Mn AOS) on their electrochemical performance were studied. The results showed that with the increase of NH2OH·HCl, the Mn AOS decreased and the corresponding pore sizes and specific surface area of birnessite increased. The synthesized nanostructured birnessite showed the highest specific capacitance of 245Fg(-1) at a current density of 0.1Ag(-1) within a potential range of 0-0.9V, and excellent cycle stability with a capacitance retention rate of 92% after 3000 cycles at a current density of 1.0Ag(-1). The present work implies that specific capacitance is mainly affected by specific surface area and pore volume, and provides a new method for the facile preparation of birnessite-type manganese oxide with excellent capacitive performance. Copyright © 2016 Elsevier Inc. All rights reserved.

Relation between grade and abundance of manganese nodules

Digital Repository Service at National Institute of Oceanography (India)

Sudhakar, M.

Data from more than 1000 locations in the Central Indian Ocean Basin (CIOB) where both bulk nodule chemistry and abundance were determined and utilized to study the relationship between grade and abundance of manganese nodule deposits. Grade...

Synthesis of binary condensed cesium-manganese phosphates in melts of polyphosphoric acids

International Nuclear Information System (INIS)

Guzeeva, L.S.; Tananaev, I.V.

1988-01-01

Cuts of Cs 2 O-MnO 2 -P 2 O 5H2 O system are investigated within 150 - 400 d egC temperature interval at P three initial relations: Mn(n), equal to 5; 7.5; 10 and P constant relation, Mn (n), equal to 15. It is shown, that interaction of manganese and cesium oxides with melts of polyphosphoric acids within 150 - 400 d egC temperature interval leads to release of three types of binary condenced phosphates of trivalent manganese and cesium: Cs 2 MnH 3 (P 2 O 7 ) 2 diphosphate, CsMnHP 3 O 10 triphosphate, Cs 3 Mn 3 (P 6 O-1 8 ) 2 cyclohexaphosphate and CsMnP 3 O 9 binary cyclotriphosphate of bivalent manganese. The released compounds are characterized by chemical, roentgenophase analyses, IR-spectrometry and thermogravimetry

Mechanism of manganese (mono and di) telluride thin-film formation and properties

Science.gov (United States)

Sharma, Raj Kishore; Singh, Gurmeet; Shul, Yong Gun; Kim, Hansung

2007-03-01

Mechanistic studies on the electrocrystallization of manganese telluride (MnTe) thin film are reported using aqueous acidic solution containing MnSO 4 and TeO 2. Tartaric acid was used for the inhibition of hydrated manganese oxide anodic growth at counter electrode. A detailed study on the mechanistic aspect of electrochemical growth of MnTe using cyclic voltametry is carried out. Conditions for electrochemical growth of manganese mono and di telluride thin films have been reported using cyclic voltammetric scans for Mn 2+, Te 4+ and combined Mn 2+ and Te 4+. X-ray diffraction showed the formation of polycrystalline MnTe films with cubic, hexagonal and orthorhombic mixed phases. MnTe film morphology was studied using scanning electron microscope. Susceptibility and electrical characterization supports the anti-ferromagnetic behavior of the as-deposited MnTe thin film.

Biogenic manganese oxide nanoparticle formation by a multimeric multicopper oxidase Mnx.

Science.gov (United States)

Romano, Christine A; Zhou, Mowei; Song, Yang; Wysocki, Vicki H; Dohnalkova, Alice C; Kovarik, Libor; Paša-Tolić, Ljiljana; Tebo, Bradley M

2017-09-29

Bacteria that produce Mn oxides are extraordinarily skilled engineers of nanomaterials that contribute significantly to global biogeochemical cycles. Their enzyme-based reaction mechanisms may be genetically tailored for environmental remediation applications or bioenergy production. However, significant challenges exist for structural characterization of the enzymes responsible for biomineralization. The active Mn oxidase in Bacillus sp. PL-12, Mnx, is a complex composed of a multicopper oxidase (MCO), MnxG, and two accessory proteins, MnxE and MnxF. MnxG shares sequence similarity with other, structurally characterized MCOs. MnxE and MnxF have no similarity to any characterized proteins. The ~200 kDa complex has been recalcitrant to crystallization, so its structure is unknown. Here, we show that native mass spectrometry defines the subunit topology and copper binding of Mnx, while high-resolution electron microscopy visualizes the protein and nascent Mn oxide minerals. These data provide critical structural information for understanding Mn biomineralization by such unexplored enzymes.Significant challenges exist for structural characterization of enzymes responsible for biomineralization. Here the authors show that native mass spectrometry and high resolution electron microscopy can define the subunit topology and copper binding of a manganese oxidizing complex, and describe early stage formation of its mineral products.

Investigation of manganese homeostasis in dogs with anaemia and ...

African Journals Online (AJOL)

Investigation of manganese homeostasis in dogs with anaemia and chronic enteropathy. Marisa da Fonseca Ferreira, Arielle Elizabeth Ann Aylor, Richard John Mellanby, Susan Mary Campbell, Adam George Gow ...

Electrochemically active manganese oxides: structural modelling, modifications induced by thermal processing and photon insertion

International Nuclear Information System (INIS)

Ripert, Michel

1990-01-01

The objective of this research study is to understand the mechanism of proton insertion into manganese dioxide. It comprised the performances of in situ discharges of two commercial samples in an electrochemical cell designed for this purpose. In order to characterise the structure of electrochemically active manganese dioxides, and particularly to elucidate the orthorhombic-hexagonal dilemma, the author proposes a crystalline-chemical approach which comprises the development of a unique structural model which takes the structure of all forms of electrochemically active manganese dioxides into account, and a numerical simulation of diffraction diagrams (X rays and neutrons) of these structures. The development of this modelling results in the development of a method which allows, from experimental diffraction diagrams, characteristic structural parameters of each sample of EMD (electrolytic manganese dioxide) or CMD (chemical manganese dioxide) to be obtained. Moreover, the observation of the structural evolution of the dioxide is possible by using in situ neutron diffraction. Reduction has been studied by using slow potential scanning voltammetry. By using these both techniques (neutron diffraction and voltammetry), it is possible to explain the structural mechanism of reduction of MnO_2 and to show the origin of the non-reversibility of the proton/MnO_2 system, to quantitatively explain the shape voltammetry curves, and to highlight experimentally for the first time the different sites of insertion of the proton

Neurotoxic effects of methylcyclopentadienyl manganese tricarbonyl (MMT) in the mouse: basis of MMT-induced seizure activity.

Science.gov (United States)

Fishman, B E; McGinley, P A; Gianutsos, G

1987-08-01

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic manganese-containing compound which is used as an additive in unleaded gasoline. One neurotoxic effect of MMT in mice is seizure activity. In this study, seizures were observed in mice treated with MMT in propylene glycol or corn oil. The LD50 associated with seizure activity was lower in mice receiving MMT in propylene glycol (152 mg/kg) than in those receiving MMT in corn oil (999 mg/kg). Manganese concentrations in the brains of mice which showed seizure activity due to MMT were higher than in those that did not (2.45 micrograms/g vs. 1.14 micrograms/g for MMT treated in propylene glycol and 3.25 micrograms/g vs. 1.63 micrograms/g for MMT in corn oil). Mice treated with manganese chloride (MnCl2) showed increases in brain manganese comparable to those of the mice showing seizure activity due to MMT, but exhibited no sign of seizure activity. MMT in non-lethal seizure-inducing doses had no effect on the accumulation of 4-aminobutyric acid (GABA) in mouse brain. However, MMT inhibited the binding of t-[3H]t-butylbicycloorthobenzoate [3H]-TBOB (a ligand for the GABA-A-receptor linked chloride channel) in mouse brain membranes with an IC50 value of 22.8 microM. The data suggest that MMT (organic manganese) or a closely related metabolite and not elemental manganese itself is responsible for the seizure activity observed. The seizure activity may be the result of an inhibitory effect of MMT at the GABA-A receptor linked chloride channel.

Neurotoxic effects of methylcyclopentadienyl manganese tricarbonyl (MMT) in the mouse: basis of MMT-induced seizure activity

International Nuclear Information System (INIS)

Fishman, B.E.; McGinley, P.A.; Gianutsos, Gerald

1987-01-01

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic manganese-containing compound which is used as an additive in unleaded gasoline. One neurotoxic effect of MMT in mice is seizure activity. In this study, seizures were observed in mice treated with MMT in propylene glycol or corn oil. The LD 50 associated with seizure activity was lower in mice receiving MMT in propylene glycol (152 mg/kg) than in those receiving MMT in corn oil (999 mg/kg). Manganese concentrations in the brains of mice which showed seizure activity due to MMT were higher than in those than did not (2.45 μg/g vs, l.14 μg/g for MMT treated in propylene glycol and 3.25 μg/g vs. l.63 μg/g for MMT in corn oil). Mice treated with manganese chloride (MnCl 2 ) showed increases in brain manganese comparable to those of the mice showing seizure activity due to MMT, but exhibited no sign of seizure activity. MMT in non-lethal seizure-inducing doses had no effect on the accumulation of 4-aminobutyric acid (GABA) in mouse brain. However, MMT inhibited the binding of t-[ 3 H] t-butylbicycloorthobenzoate [ 3 H]-TBOB (a ligand for the GABA-A-receptor linked chloride channel) in mouse brain membranes with an IC 50 value of 22.8 μM. The data suggest that MMT (organic manganese) or a closely related metabolite and not elemental manganese itself is responsible for the seizure activity observed. The seizure activity may be the result of an inhibitory effect of MMT at the GABA-A receptor linked chloride channel. 20 refs. (author)

A Review on the Synthesis of Manganese Oxide Nanomaterials and Their Applications on Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Xiaodi Liu

2013-01-01

Full Text Available Most recently, manganese oxides nanomaterials, including MnO and MnO2, have attracted great interest as anode materials in lithium-ion batteries (LIBs for their high theoretical capacity, environmental benignity, low cost, and special properties. Up to now, manganese oxides nanostructures with excellent properties and various morphologies have been successfully synthesized. Herein, we provide an in-depth discussion of recent development of the synthesis of manganese oxides nanomaterials and their application in the field of LIBs.

Manganese content of Orosi valley fodder and its effect on hair concentration and reproduction in dairy cows

International Nuclear Information System (INIS)

Fonseca, H.; Lang, C.

1976-01-01

An integrated study has been made of the relationship - which has been established separately by the various authors whose names are listed - existing between the content of manganese in fodder, its concentration in the hair of dairy cattle and its effects on the reproductive behaviour of these animals. The study was carried out in Orosi valley (Costa Rica) and included: determination of the manganese content of eight types of fodder from 48 sampling points distributed over five sectors; determination of the concentration of this mineral in the hair of 14 and 16 cows, respectively, from two dairy farms (A and B); and, lastly, an analytical evaluation of the reproduction indices obtained, to check on the findings of other authors. For comparison purposes use was made of the fodder and hair indices obtained at another large dairy farm (C) located in an area that is considered normal as far as manganese content of fodder is concerned and in which the fertility index was high. These studies show that each type of fodder studied has its own manganese uptake properties; that the manganese content of the hair (91, 73 and 18 ppm respectively) in farms A, B and C is related directly to the content of this element in forage (210, 130 and 74 ppm respectively); lastly, they show that a manganese content of more than 100 ppm in fodder can be one of the factors affecting the reproductive capacity of dairy cattle herds: 2.30 and 2.18 couplings per live birth and parturition indices of 57.8 and 64.2% in farms A and B with a high manganese content in the fodder, as against 1.49 couplings per birth and parturition indices of 90% in farm C with a normal manganese content in fodder. (author)

Manganese and lead in dust fall accumulation in elementary schools near a ferromanganese alloy plant

International Nuclear Information System (INIS)

Menezes-Filho, José Antonio; Souza, Karine O. Fraga de; Rodrigues, Juliana L. Gomes; Santos, Nathália Ribeiro dos; Bandeira, Matheus de Jesus; Koin, Ng Lai; Oliveira, Sérgio S. do Prado; Godoy, Ana Leonor P. Campos

2016-01-01

Previous studies have shown elevated airborne manganese (Mn) in villages adjacent to a Mn alloy production plant in Brazil and negative associations between biomarkers of Mn and children's cognition and behavior. Since small Mn particles may be carried for long distances, we measured manganese (Mn) and lead (Pb) dust fall accumulation in 15 elementary schools, located between 1.25 and 6.48 km from the plant in the municipality of Simões Filho, Bahia, Brazil. Passive samplers (polyethylene Petri dishes) were set in interior and exterior environments. After 30 days, the samplers’ content was solubilized with diluted nitric acid and Mn and Pb levels were analyzed by electrothermal absorption spectrometry. The overall geometric mean and range of Mn and Pb accumulation in dust fall (loading rates) were 1582 μg Mn/m 2 /30 days (37–37,967) and 43.2 μg Pb/m 2 /30 days (2.9–210.4). A logarithmic decrease in interior and exterior Mn loading rates was observed with distance from the ferro-manganese alloy plant. Multiple regression analyses of log-transformed Mn loading rate within the schools showed a positive association with Mn levels in outdoor dust, a negative association with distance from the plant; as well, wind direction (downwind>upwind) and school location (urban>rural) entered significantly into the model. For the interior school environments, located within a 2-km radius from the plant, loading rate was, on average, 190 times higher than the Mn levels reported by Gulson et al., (2014) in daycare centers in Sydney, Australia, using a similar method. Pb loading rates were not associated with distance from the plant and were lower than the rates observed in the same daycare centers in Sydney. Our findings suggest that a significant portion of the children in this town in Brazil may be exposed to airborne Mn at concentrations that may affect their neurodevelopment. - Highlights: • Manganese levels in settled dust in schools are inversely associated

Manganese and lead in dust fall accumulation in elementary schools near a ferromanganese alloy plant

Energy Technology Data Exchange (ETDEWEB)

Menezes-Filho, José Antonio, E-mail: antomen@ufba.br [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Souza, Karine O. Fraga de, E-mail: karinefraga11@hotmail.com [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Rodrigues, Juliana L. Gomes, E-mail: juuhrodrigues@icloud.com [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Santos, Nathália Ribeiro dos, E-mail: nathalia-rib@hotmail.com [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Bandeira, Matheus de Jesus, E-mail: matheusbandeira1@hotmail.com [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Koin, Ng Lai, E-mail: nglaikoin@hotmail.com [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Oliveira, Sérgio S. do Prado, E-mail: sergiosprado.33@gmail.com [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); Godoy, Ana Leonor P. Campos, E-mail: leonor.godoy@ufba.br [Federal University of Bahia, College of Pharmacy, Laboratory of Toxicology, Avenue Barão Jeremoabo, s/n, Ondina, 40170-115 Salvador, Bahia (Brazil); and others

2016-07-15

Previous studies have shown elevated airborne manganese (Mn) in villages adjacent to a Mn alloy production plant in Brazil and negative associations between biomarkers of Mn and children's cognition and behavior. Since small Mn particles may be carried for long distances, we measured manganese (Mn) and lead (Pb) dust fall accumulation in 15 elementary schools, located between 1.25 and 6.48 km from the plant in the municipality of Simões Filho, Bahia, Brazil. Passive samplers (polyethylene Petri dishes) were set in interior and exterior environments. After 30 days, the samplers’ content was solubilized with diluted nitric acid and Mn and Pb levels were analyzed by electrothermal absorption spectrometry. The overall geometric mean and range of Mn and Pb accumulation in dust fall (loading rates) were 1582 μg Mn/m{sup 2}/30 days (37–37,967) and 43.2 μg Pb/m{sup 2}/30 days (2.9–210.4). A logarithmic decrease in interior and exterior Mn loading rates was observed with distance from the ferro-manganese alloy plant. Multiple regression analyses of log-transformed Mn loading rate within the schools showed a positive association with Mn levels in outdoor dust, a negative association with distance from the plant; as well, wind direction (downwind>upwind) and school location (urban>rural) entered significantly into the model. For the interior school environments, located within a 2-km radius from the plant, loading rate was, on average, 190 times higher than the Mn levels reported by Gulson et al., (2014) in daycare centers in Sydney, Australia, using a similar method. Pb loading rates were not associated with distance from the plant and were lower than the rates observed in the same daycare centers in Sydney. Our findings suggest that a significant portion of the children in this town in Brazil may be exposed to airborne Mn at concentrations that may affect their neurodevelopment. - Highlights: • Manganese levels in settled dust in schools are inversely

Surface modifications induced by yttrium implantation on low manganese-carbon steel

Energy Technology Data Exchange (ETDEWEB)

Caudron, E.; Buscail, H. [Univ. Blaise Pascal Clermont-Fd II, Le Puy en Velay (France). Lab. Vellave d' Elaboration et d' Etude des Materiaux; Haanapel, V.A.C.; Jacob, Y.P.; Stroosnijder, M.F. [Institute for Health and Consumer Protection, Joint Research Center, The European Commission, 21020, Ispra (Italy)

1999-12-15

Low manganese-carbon steel samples were ion implanted with yttrium. Sample compositions and structures were investigated before and after yttrium implantations to determine the yttrium distribution in the sample. Yttrium implantation effects were characterized using several analytical and structural techniques such as X-ray photoelectron spectroscopy, reflection high energy electron diffraction, X-ray diffraction, glancing angle X-ray diffraction and Rutherford backscattering spectrometry. In this paper it is shown that correlation between composition and structural analyses provides an understanding of the main compounds induced by yttrium implantation in low manganese-carbon steel. (orig.)

Fabrication of birnessite-type layered manganese oxide films for super capacitors

Energy Technology Data Exchange (ETDEWEB)

Zhou, Y.K.; Dorval-Douville, G.; Favier, F. [Montpellier-2 Univ., LAMMI, UMR CNRS 5072, 34 (France)

2004-07-01

Birnessite-type layered manganese oxide films were anodically deposited at the surface of an inexpensive stainless steel. MnSO{sub 4} plating solutions were used at various potentials and for various durations. X-ray diffraction and scanning electron microscopy were used to examine the material structure and surface morphologies of obtained manganese oxide films. The capacitive characteristics and stability of these oxides were systematically investigated by means of cyclic voltammetry method in aqueous electrolytes. Deposition conditions affected the oxides structure and morphologies, and consequently greatly affected their electrochemical capacitance performance. (authors)

The evolutionarily conserved protein PHOTOSYNTHESIS AFFECTED MUTANT71 is required for efficient manganese uptake at the thylakoid membrane in Arabidopsis

DEFF Research Database (Denmark)

Schneider, Anja; Steinberger, Iris; Herdean, Andrei

2016-01-01

In plants, algae, and cyanobacteria, photosystem II (PSII) catalyzes the light-driven oxidation of water. The oxygen-evolving complex of PSII is a Mn4CaO5 cluster embedded in a well-defined protein environment in the thylakoid membrane. However, transport of manganese and calcium into the thylako...... was restored by supplementation with Mn2+, but not Ca2+. Furthermore, PAM71 suppressed the Mn2+-sensitive phenotype of the yeast mutant Δpmr1. Therefore, PAM71 presumably functions in Mn2+ uptake into thylakoids to ensure optimal PSII performance....

Cognitive Function Related to Environmental Exposure to Manganese

Science.gov (United States)

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...

Pilot study points way to iron/manganese removal

Energy Technology Data Exchange (ETDEWEB)

Qureshi, N.; Barnes, A. [Progressive Consulting Engineers Inc., Minneapolis, MN (United States)

1994-12-31

The use of coal, greensand and sand in filters for removing iron and manganese from the Brooklyn Park, Minnesota, water supply was investigated. The most effective and economic treatment involved using a dual media filtration and potassium permanganate as the oxidant.

Synthesis and characterization of monodispersed orthorhombic manganese oxide nanoparticles produced by Bacillus sp. cells simultaneous to its bioremediation

Energy Technology Data Exchange (ETDEWEB)

Sinha, Arvind [Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India); Singh, Vidya Nand; Mehta, Bodh Raj [Thin Film Laboratory, Department of Physics, Indian Institute of Technology, Delhi Hauz Khas, New Delhi 110016 (India); Khare, Sunil Kumar, E-mail: skhare@rocketmail.com [Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)

2011-08-30

Highlights: {yields} An efficient process wherein remediated manganese is synthesized into nanoparticles. {yields} A microbial process for manganese nanoparticle synthesis from metal waste streams. {yields} Nanoparticles characterized as monodispersed, spherical and 4.62 {+-} 0.14 nm sized MnO{sub 2}. -- Abstract: A heavy metal resistant strain of Bacillus sp. (MTCC10650) is reported. The strain exhibited the property of bioaccumulating manganese, simultaneous to its remediation. The nanoparticles thus formed were characterized and identified using energy dispersive X-ray analysis (EDAX), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and atomic force microscopy (AFM). When the cells were challenged with manganese, the cells effectively synthesized nanoparticles of average size 4.62 {+-} 0.14 nm. These were mostly spherical and monodispersed. The ex situ enzymatically synthesized nanoparticles exhibited an absorbance maximum at 329 nm. These were more discrete, small and uniform, than the manganese oxide nanoparticles recovered after cell sonication. The use of Bacillus sp. cells seems promising and advantageous approach. Since, it serves dual purposes of (i) remediation and (ii) nanoparticle synthesis. Considering the increasing demand of developing environmental friendly and cost effective technologies for nanoparticle synthesis, these cells can be exploited for the remediation of manganese from the environment in conjunction with development of a greener process for the controlled synthesis of manganese oxide nanoparticles.

Synthesis and characterization of monodispersed orthorhombic manganese oxide nanoparticles produced by Bacillus sp. cells simultaneous to its bioremediation

International Nuclear Information System (INIS)

Sinha, Arvind; Singh, Vidya Nand; Mehta, Bodh Raj; Khare, Sunil Kumar

2011-01-01

Highlights: → An efficient process wherein remediated manganese is synthesized into nanoparticles. → A microbial process for manganese nanoparticle synthesis from metal waste streams. → Nanoparticles characterized as monodispersed, spherical and 4.62 ± 0.14 nm sized MnO 2 . -- Abstract: A heavy metal resistant strain of Bacillus sp. (MTCC10650) is reported. The strain exhibited the property of bioaccumulating manganese, simultaneous to its remediation. The nanoparticles thus formed were characterized and identified using energy dispersive X-ray analysis (EDAX), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and atomic force microscopy (AFM). When the cells were challenged with manganese, the cells effectively synthesized nanoparticles of average size 4.62 ± 0.14 nm. These were mostly spherical and monodispersed. The ex situ enzymatically synthesized nanoparticles exhibited an absorbance maximum at 329 nm. These were more discrete, small and uniform, than the manganese oxide nanoparticles recovered after cell sonication. The use of Bacillus sp. cells seems promising and advantageous approach. Since, it serves dual purposes of (i) remediation and (ii) nanoparticle synthesis. Considering the increasing demand of developing environmental friendly and cost effective technologies for nanoparticle synthesis, these cells can be exploited for the remediation of manganese from the environment in conjunction with development of a greener process for the controlled synthesis of manganese oxide nanoparticles.

Methylcyclopentadienyl manganese tricarbonyl (MMT), plant uptake and effects on metabolism

Energy Technology Data Exchange (ETDEWEB)

Jones, A.R.; Lytle, C.M.; Stone, R.L.; Smith, B.N [Department of Botany and Range Science, Brigham Young University, Provo (United States); Hansen, L.D. [Department of Chemistry and Biochemistry, Brigham Young University, Provo (United States)

2000-04-01

In the USA and Canada, methylcyclopentadienyl manganese (MMT) is currently added to gasoline to replace tetraethyl lead as an antiknock fuel additive. Manganese concentrations in roadside soil and plants are increasing and correlated with distance from the roadway, traffic volume, plant type, and microhabitat. Radish (Raphanus sativus L.) seedlings were treated for either five or thirty-five days with different levels of manganous chloride (0-1000ppm). Metabolic heat rates (q) and respiration rates (R{sub CO{sub 2}}), measured calorimetrically, indicated severe stress at Mn concentrations between 10 and 100ppm and at temperatures above 20C. Predicted growth rates (R{sub SG}) also decreased in these circumstances.

A microbial-mineralization-inspired approach for synthesis of manganese oxide nanostructures with controlled oxidation states and morphologies

Energy Technology Data Exchange (ETDEWEB)

Oba, Manabu; Oaki, Yuya; Imai, Hiroaki [Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2010-12-21

Manganese oxide nanostructures are synthesized by a route inspired by microbial mineralization in nature. The combination of organic molecules, which include antioxidizing and chelating agents, facilitates the parallel control of oxidation states and morphologies in an aqueous solution at room temperature. Divalent manganese hydroxide (Mn(OH){sub 2}) is selectively obtained as a stable dried powder by using a combination of ascorbic acid as an antioxidizing agent and other organic molecules with the ability to chelate to manganese ions. The topotactic oxidation of the resultant Mn(OH){sub 2} leads to the selective formation of trivalent manganese oxyhydroxide ({beta}-MnOOH) and trivalent/tetravalent sodium manganese oxide (birnessite, Na{sub 0.55}Mn{sub 2}O{sub 4}.1.5H{sub 2}O). For microbial mineralization in nature, similar synthetic routes via intermediates have been proposed in earlier works. Therefore, these synthetic routes, which include in the present study the parallel control over oxidation states and morphologies of manganese oxides, can be regarded as new biomimetic routes for synthesis of transition metal oxide nanostructures. As a potential application, it is demonstrated that the resultant {beta}-MnOOH nanostructures perform as a cathode material for lithium ion batteries. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The multiple Dirichlet product and the multiple Dirichlet series

OpenAIRE

Onozuka, Tomokazu

2016-01-01

First, we define the multiple Dirichlet product and study the properties of it. From those properties, we obtain a zero-free region of a multiple Dirichlet series and a multiple Dirichlet series expression of the reciprocal of a multiple Dirichlet series.

Effect of intranasal manganese administration on neurotransmission and spatial learning in rats

Energy Technology Data Exchange (ETDEWEB)

Blecharz-Klin, Kamilla; Piechal, Agnieszka; Joniec-Maciejak, Ilona; Pyrzanowska, Justyna; Widy-Tyszkiewicz, Ewa, E-mail: etyszkiewicz@wum.edu.pl

2012-11-15

The effect of intranasal manganese chloride (MnCl{sub 2}·4H{sub 2}O) exposure on spatial learning, memory and motor activity was estimated in Morris water maze task in adult rats. Three-month-old male Wistar rats received for 2 weeks MnCl{sub 2}·4H{sub 2}O at two doses the following: 0.2 mg/kg b.w. (Mn0.2) or 0.8 mg/kg b.w. (Mn0.8) per day. Control (Con) and manganese-exposed groups were observed for behavioral performance and learning in water maze. ANOVA for repeated measurements did not show any significant differences in acquisition in the water maze between the groups. However, the results of the probe trial on day 5, exhibited spatial memory deficits following manganese treatment. After completion of the behavioral experiment, the regional brain concentrations of neurotransmitters and their metabolites were determined via HPLC in selected brain regions, i.e. prefrontal cortex, hippocampus and striatum. ANOVA demonstrated significant differences in the content of monoamines and metabolites between the treatment groups compared to the controls. Negative correlations between platform crossings on the previous platform position in Southeast (SE) quadrant during the probe trial and neurotransmitter turnover suggest that impairment of spatial memory and cognitive performance after manganese (Mn) treatment is associated with modulation of the serotonergic, noradrenergic and dopaminergic neurotransmission in the brain. These findings show that intranasally applied Mn can impair spatial memory with significant changes in the tissue level and metabolism of monoamines in several brain regions. -- Highlights: ► Intranasal exposure to manganese in rats impairs spatial memory in the water maze. ► Regional changes in levels of neurotransmitters in the brain have been identified. ► Cognitive disorder correlates with modulation of 5-HT, NA and DA neurotransmission.

Effect of intranasal manganese administration on neurotransmission and spatial learning in rats

International Nuclear Information System (INIS)

Blecharz-Klin, Kamilla; Piechal, Agnieszka; Joniec-Maciejak, Ilona; Pyrzanowska, Justyna; Widy-Tyszkiewicz, Ewa

2012-01-01

The effect of intranasal manganese chloride (MnCl 2 ·4H 2 O) exposure on spatial learning, memory and motor activity was estimated in Morris water maze task in adult rats. Three-month-old male Wistar rats received for 2 weeks MnCl 2 ·4H 2 O at two doses the following: 0.2 mg/kg b.w. (Mn0.2) or 0.8 mg/kg b.w. (Mn0.8) per day. Control (Con) and manganese-exposed groups were observed for behavioral performance and learning in water maze. ANOVA for repeated measurements did not show any significant differences in acquisition in the water maze between the groups. However, the results of the probe trial on day 5, exhibited spatial memory deficits following manganese treatment. After completion of the behavioral experiment, the regional brain concentrations of neurotransmitters and their metabolites were determined via HPLC in selected brain regions, i.e. prefrontal cortex, hippocampus and striatum. ANOVA demonstrated significant differences in the content of monoamines and metabolites between the treatment groups compared to the controls. Negative correlations between platform crossings on the previous platform position in Southeast (SE) quadrant during the probe trial and neurotransmitter turnover suggest that impairment of spatial memory and cognitive performance after manganese (Mn) treatment is associated with modulation of the serotonergic, noradrenergic and dopaminergic neurotransmission in the brain. These findings show that intranasally applied Mn can impair spatial memory with significant changes in the tissue level and metabolism of monoamines in several brain regions. -- Highlights: ► Intranasal exposure to manganese in rats impairs spatial memory in the water maze. ► Regional changes in levels of neurotransmitters in the brain have been identified. ► Cognitive disorder correlates with modulation of 5-HT, NA and DA neurotransmission.

[Expression of heat shock protein 70 and its mRNA in career exposure to manganese].

Science.gov (United States)

Chen, Wenwen; Shao, Hua; Chi, Mingfeng; Zhang, Zhihu; Shan, Yongle; Zou, Wei

2015-10-01

To analyze the expression levels of heat shock protein70 (HSPs70) and HSPs70 mRNA in different exposure to manganese, and research the neuroprotective effect on the career exposure to manganese. From 2008 to 2009, with cross-sectional study design, and in a locomotive and rolling stock works, by stratified random sampling method, the exposed sample consisted of 180 welders from different welding shops and 100 unexposed in the last three years, non-welder controls with age-matched workers of similar socioeconomic status from the same industry. The control workers had not been exposed to neurotoxic chemicals. The mRNA expressions of four different metabolic enzyme were detected by SYBR Green I quantitative real-time polymerase chain reaction. The expression levels of the two enzymes mRNA in different exposure to manganese were analyzed. The expressions of HSPs70 were detected by Western blot. The concentration of air manganese was determined by GFAAS. The average concentration of 8 h time (8h-TWA) was used to express the level of individual exposure to manganese, according to the air manganese workplace occupational exposure limit (8h-TWA=0.15 mg/m3), the exposed group is divided into high exposed group (>0.15 mg/m3) and low exposure group (<0.15 mg/m3). The individuals exposed to manganese dose of exposed group ((0.25±0.31) mg/m3) was higher than the control group ((0.06±0.02) mg/m3) (t=6.15, P=0.001); individuals exposed to manganese dose of high exposure group for (0.42±0.34) mg/m3, which was higher than low exposure group (0.09±0.07) mg/m3 (t=9.80, P=0.001). HSPs70 mRNA and protein of exposure group (5.65±0.21, 3.26±0.15) were higher than the reference group (0.41±0.03, 1.32±0.12) (t=18.91, t=8.68, P=0.001). HSP70 mRNA and protein of high exposure group (6.48±0.37, 3.67±0.26) were higher than the low exposure group (5.15±0.23, 3.02±0.19) (t=3.24, t=2.01, P=0.003, P=0.043). The expression of peripheral blood lymphocytes HSPs70 level and HSPs70 m

A zinc-resistant human epithelial cell line is impaired in cadmium and manganese import

International Nuclear Information System (INIS)

Rousselet, Estelle; Richaud, Pierre; Douki, Thierry; Chantegrel, Jocelyne Garcia; Favier, Alain; Bouron, Alexandre; Moulis, Jean-Marc

2008-01-01

A human epithelial cell line (HZR) growing with high zinc concentrations has been analyzed for its ability to sustain high cadmium concentrations. Exposure to up to 200 μM of cadmium acetate for 24 h hardly impacted viability, whereas most of parental HeLa cells were killed by less than 10 μM of cadmium. Upon challenge by 35 fold higher cadmium concentrations than HeLa cells, HZR cells did not display increased DNA damage, increased protein oxidation, or changed intracellular cadmium localization. Rather, the main cause of resistance against cadmium was by avoiding cadmium entry into cells, which differs from that against zinc as the latter accumulates inside cells. The zinc-resistant phenotype of these cells was shown to also impair extracellular manganese uptake. Manganese and cadmium competed for entry into HeLa cells. Probing formerly identified cadmium or manganese transport systems in different animal cells did not evidence any significant change between HeLa and HZR cells. These results reveal zinc adaptation influences manganese and cadmium cellular traffic and they highlight previously unknown connections among homeostasis of divalent metals

Manganese and Gd-DTPA stearyl liposomes as reticuloendothelial-system-specific MR imaging contrast agents

International Nuclear Information System (INIS)

Wuthrich, R.; Schwendener, R.; Duewell, S.; VonSchulthess, G.K.; Fuchs, W.A.

1988-01-01

Liposomes can be used to target metal ions as MR contrast agents to liver and spleen. It was the aim of this work to examine unilamellar liposomes containing manganese and gadolinium ions with respect to their targetting ability, contrast enhancement, and in vivo kinetics in rats and dogs. Unilamellar liposomes containing DTPA stearate were complexed with Mn/sup 2+/ and Gd/sup 3+/ resulting in vesicles of 30-40 nm. Injected into rats, approximately 35% of manganese liposomes were present in the liver after 30-60 minutes, and after 24 hours more than 80% had been eliminated. The pharmacokinetics of gadolinium were more protracted. In MR imaging, a reduction in the T1 of the liver parenchyma from 450 to 170 and 280 msec was observed for manganese and gadolinium liposomes (0.03 mmol/kg body weight), respectively, with the liver appearing as bright as fat. Manganese (and Gd-DTPA) stearyl liposomes are potential organ-selective contrast agents for liver and spleen and are eliminated through a hepatobiliary route

Electrodeposition of Manganese-Nickel Oxide Films on a Graphite Sheet for Electrochemical Capacitor Applications

Directory of Open Access Journals (Sweden)

Hae-Min Lee

2014-01-01

Full Text Available Manganese-nickel (Mn-Ni oxide films were electrodeposited on a graphite sheet in a bath consisting of manganese acetate and nickel chloride, and the structural, morphological, and electrochemical properties of these films were investigated. The electrodeposited Mn-Ni oxide films had porous structures covered with nanofibers. The X-ray diffractometer pattern revealed the presence of separate manganese oxide (g-MnO2 and nickel oxide (NiO in the films. The electrodeposited Mn-Ni oxide electrode exhibited a specific capacitance of 424 F/g in Na2SO4 electrolyte. This electrode maintained 86% of its initial specific capacitance over 2000 cycles of the charge-discharge operation, showing good cycling stability.

Bentonite Modification with Manganese Oxides and Its Characterization

Czech Academy of Sciences Publication Activity Database

Dolinská, S.; Schütz, T.; Znamenáčková, I.; Lovás, M.; Vaculíková, Lenka

2015-01-01

Roč. 35, č. 1 (2015), s. 213-218 ISSN 1640-4920 Institutional support: RVO:68145535 Keywords : bentonite * natrification * manganese oxide Subject RIV: CB - Analytical Chemistry, Separation http://www.potopk.com.pl/ Full _text/2015_full/IM%202-2015-a35.pdf

from Tailings Material of Ghana Manganese Company (GMC)

African Journals Online (AJOL)

user

arrive at large scale secondary manganese sourcing by recycling from steel, beverage ... rpm, and the tangential flow of water through jets was at the rate of 210.10 ... the limitation of the machine‟s discharge pipes, frac- tions coarser than 20 ...

Preparation of electrochromic thin films by transformation of manganese(II) carbonate

Science.gov (United States)

Stojkovikj, Sasho; Najdoski, Metodija; Koleva, Violeta; Demiri, Sani

2013-10-01

A new chemical bath method for deposition of manganese(II) carbonate thin film on electroconductive FTO glass substrates is designed. The homogeneous thin films with thickness in the range of 70 to 500 nm are deposited at about 98 °C from aqueous solution containing urea and MnCl2. The chemical process is based on a low temperature hydrolysis of the manganese complexes with urea. Three types of films are under consideration: as-deposited, annealed and electrochemically transformed thin films. The structure of the films is studied by XRD, IR and Raman spectroscopy. Electrochemical and optical properties are examined in eight different electrolytes (neutral and alkaline) and the best results are achieved in two component aqueous solution of 0.1 M KNO3 and 0.01 M KOH. It is established that the as-deposited MnCO3 film undergoes electrochemically transformation into birnessite-type manganese(IV) oxide films, which exhibit electrochromic color changes (from bright brown to pale yellow and vice versa) with 30% difference in the transmittance of the colored and bleached state at 400 nm.

Iron and manganese in anaerobic respiration: environmental significance, physiology, and regulation

Science.gov (United States)

Nealson, K. H.; Saffarini, D.

1994-01-01

Dissimilatory iron and/or manganese reduction is known to occur in several organisms, including anaerobic sulfur-reducing organisms such as Geobacter metallireducens or Desulfuromonas acetoxidans, and facultative aerobes such as Shewanella putrefaciens. These bacteria couple both carbon oxidation and growth to the reduction of these metals, and inhibitor and competition experiments suggest that Mn(IV) and Fe(III) are efficient electron acceptors similar to nitrate in redox abilities and capable of out-competing electron acceptors of lower potential, such as sulfate (sulfate reduction) or CO2 (methanogenesis). Field studies of iron and/or manganese reduction suggest that organisms with such metabolic abilities play important roles in coupling the oxidation of organic carbon to metal reduction under anaerobic conditions. Because both iron and manganese oxides are solids or colloids, they tend to settle downward in aquatic environments, providing a physical mechanism for the movement of oxidizing potential into anoxic zones. The resulting biogeochemical metal cycles have a strong impact on many other elements including carbon, sulfur, phosphorous, and trace metals.

The distribution of uranium in some Pacific manganese nodules and crusts

International Nuclear Information System (INIS)

Kunzendorf, H.; Glasby, G.P.; Plueger, W.L.; Friedrich, G.H.

1982-01-01

A total of 1386 bulk samples of manganese nodules from several areas of the North and South Pacific were analysed for uranium; variations in the U contents of nodules within individual nodules and crusts have been documented on a local scale and on a regional scale. Uranium appears to be one of those elements not associated with the biogenic cycling of elements into nodules in the equatorial high-productivity zone. The principal factor controlling these variations appears to be the clear association of U with Fe in the nodules. Uranium is therefore most probably coprecipitated with Fe from seawater in an iron-rich ferromanganese oxide phase. This explains the higher U contents of nodules containing MnO 2 compared to 10A manganite as the principal manganese oxide phase. Data for a manganese crust from the equatorial North Pacific nodule belt suggest normal seawater deposition for uranium and other metals (Mn, Fe, Ni and Cu) superimposed on possibly basalt alteration as the principal growth mechanisms for the crust. (Auth.)

Insulin sensitivity to trace metals (Chromium, manganese) in type 2 diabetic patients and diabetic individuals

International Nuclear Information System (INIS)

Hajra, B.; Orakzai, S.A.; Faryal, U.; Hassan, M.

2016-01-01

Background: Diabetes mellitus constitutes one of the most important problems in developing and non-developing countries. The purpose of the study to estimate the concentrations of Chromium and Manganese in diabetic and non-diabetic population of Hazara division. The cross sectional comparative study was carried out on one hundred blood samples of Type 2 Diabetic patients collected non-randomly from Ayub Teaching Hospital and one hundred normal healthy controls from Women Medical College Abbottabad from September 2014 to April 2015. Methods: The study included two hundred subjects. Among them 100 were diabetic and 100 non diabetic respectively. The blood samples were collected from Ayub Medical College, Abbottabad. The serum Chromium and Manganese levels were determined by Atomic Absorption spectrophotometer. Results: Serum Chromium and Manganese levels were decreased in diabetic and increased in non-diabetic patients. Conclusion: Low serum level of Chromium and manganese were found in diabetic patients as compare to non-diabetic individuals. (author)

Heavy metal toxicities in vegetable crops. VI. The effect of potassium and calcium concentration in the nutrient solution on manganese toxicities in vegetable crops

Energy Technology Data Exchange (ETDEWEB)

Osawa, T; Ikeda, H

1977-01-01

Eight species of vegetable crops were grown in solution culture in order to investigate the effect of potassium and calcium concentration in the nutrient solution on manganese toxicities in vegetable crops. Manganese was supplied at levels of 0.5, 30, and 100 ppm. At each manganese level potassium or calcium was supplied at rates of 2, 6, and 18 me/l. The pH of the nutrient solution was adjusted to 5. Manganese excess induced interveinal chlorosis on upper leaves in bean, eggplant, pepper, and spinach, and marginal chlorosis on lower leaves in cabbage, lettuce, and celery. In Welsh onions chlorosis was induced on lower leaves. Increasing the supply of potassium and calcium reduced the severity of manganese-induced chlorosis. This beneficial effect was generally more marked with calcium than with potassium. Increasing the supply of potassium and calcium was effective in alleviating the growth reduction of vegetable crops due to manganese excess. This effect also was more marked with calcium than with potassium. With increasing manganese level in the nutrient solution the manganese concentration in leaves of vegetable crops increased. Increasing the supply of potassium and calcium inhibited excessive accumulation of manganese in leaves. The influence of calcium was stronger than that of potassium. In any of the vegetable crops tested, regardless of potassium and calcium treatments, manganese concentration in leaves was closely related to manganese toxicities; the more the accumulation of manganese in leaves increased, the more the severity of manganese-induced chlorosis and growth reduction increased.

Synergistic Manganese(I) C-H Activation Catalysis in Continuous Flow: Chemoselective Hydroarylation.

Science.gov (United States)

Wang, Hui; Pesciaioli, Fabio; Oliveira, João C A; Warratz, Svenja; Ackermann, Lutz

2017-11-20

Chemoselective hydroarylations were accomplished by a novel synergistic Brønsted acid/manganese(I)-catalyzed C-H activation manifold. Thus, alkynes bearing O-leaving groups could, for the first time, be employed for C-H alkenylations without concurrent β-O elimination, thereby setting the stage for versatile late-stage diversifications. Also described is the first manganese-catalyzed C-H activation in continuous flow, thus enabling efficient hydroarylations within only 20 minutes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lupines, manganese, and devil-sickness: an Anglo-Saxon medical response to epilepsy.

Science.gov (United States)

Dendle, P

2001-01-01

The most frequently prescribed herb for "devil-sickness" in the vernacular medical books from Anglo-Saxon England, the lupine, is exceptionally high in manganese. Since manganese depletion has been linked with recurring seizures in both clinical and experimental studies, it is possible that lupine administration responded to the particular pathophysiology of epilepsy. Lupine is not prescribed for seizures in classical Mediterranean medical sources, implying that the Northern European peoples (if not the Anglo-Saxons themselves) discovered whatever anticonvulsive properties the herb may exhibit.

Hydrogeochemistry in a relatively unmodified subtropical catchment: Insights regarding the health and aesthetic risks of manganese

Directory of Open Access Journals (Sweden)

Adam K. Rose

2017-10-01

New hydrological insights for region: Results show that the hydrogeochemistry of Baffle Creek was predominantly driven by rain events, with differing responses to varying magnitudes of rain and discharge. Following a flushing event, dissolved aluminium and nitrate increased in the surface and drinking water, whereas manganese and ammonia were undetectable in the drinking water and occurred only in small concentrations in the surface waters. In contrast, when rainfall events occurred without an associated flush, manganese, iron and ammonia concentrations increased in the drinking water. The hydrochemistry of manganese and iron in the supply chain infrastructure was strongly positively correlated with ammonia, and aluminium correlated with nitrate concentrations. Currently the drinking water supply does not pose a threat to chronic manganese exposure for humans, however elevated concentrations are experienced periodically; and may become more problematic under climate change scenarios.

Rapidly reversible redox transformation in nanophase manganese oxides at room temperature triggered by changes in hydration.

Science.gov (United States)

Birkner, Nancy; Navrotsky, Alexandra

2014-04-29

Chemisorption of water onto anhydrous nanophase manganese oxide surfaces promotes rapidly reversible redox phase changes as confirmed by calorimetry, X-ray diffraction, and titration for manganese average oxidation state. Surface reduction of bixbyite (Mn2O3) to hausmannite (Mn3O4) occurs in nanoparticles under conditions where no such reactions are seen or expected on grounds of bulk thermodynamics in coarse-grained materials. Additionally, transformation does not occur on nanosurfaces passivated by at least 2% coverage of what is likely an amorphous manganese oxide layer. The transformation is due to thermodynamic control arising from differences in surface energies of the two phases (Mn2O3 and Mn3O4) under wet and dry conditions. Such reversible and rapid transformation near room temperature may affect the behavior of manganese oxides in technological applications and in geologic and environmental settings.

Wustite-based photoelectrodes with lithium, hydrogen, sodium, magnesium, manganese, zinc and nickel additives

Science.gov (United States)

Carter, Emily Ann; Toroker, Maytal Caspary

2017-08-15

A photoelectrode, photovoltaic device and photoelectrochemical cell and methods of making are disclosed. The photoelectrode includes an electrode at least partially formed of FeO combined with at least one of lithium, hydrogen, sodium, magnesium, manganese, zinc, and nickel. The electrode may be doped with at least one of lithium, hydrogen, and sodium. The electrode may be alloyed with at least one of magnesium, manganese, zinc, and nickel.

Anodically generated manganese(III) sulphate for the oxidation of ...

Indian Academy of Sciences (India)

Unknown

oxidation of dipeptides in aqueous sulphuric acid medium: A kinetic study ... acetic acid (TFA) and N-methylmorpholine (NMM) were purchased ... and chloroform–methanol– acetic acid .... tion), manganese(II) sulphate and water (to keep the.

Manganese(III Porphyrin-based Potentiometric Sensors for Diclofenac Assay in Pharmaceutical Preparations

Directory of Open Access Journals (Sweden)

Eugenia Fagadar-Cosma

2010-09-01

Full Text Available Two manganese(III porphyrins: manganese(III tetraphenylporphyrin chloride and manganese(III-tetrakis(3-hydroxyphenylporphyrin chloride were tested as ionophores for the construction of new diclofenac−selective electrodes. The electroactive material was incorporated either in PVC or a sol−gel matrix. The effect of different plasticizers and additives (anionic and cationic on the potentiometric response was studied. The best results were obtained for the PVC membrane plasticized with dioctylphtalate and having sodium tetraphenylborate as a lipophilic anionic additive incorporated. The sensor response was linear in the concentration range 3 × 10−6 – 1 × 10−2 M with a slope of −59.7 mV/dec diclofenac, a detection limit of 1.5 × 10−6 M and very good selectivity coefficients. It was used for the determination of diclofenac in pharmaceutical preparations, by direct potentiometry. The results were compared with those obtained by the HPLC reference method and a good agreement was found between the two methods.

Characteristics and defluoridation performance of granular activated carbons coated with manganese oxides

International Nuclear Information System (INIS)

Ma Yue; Wang Shuguang; Fan Maohong; Gong Wenxin; Gao Baoyu

2009-01-01

Using a redox process, granular activated carbon (GAC) was coated with manganese oxides to enhance its ability to adsorb fluoride from an aqueous solution. Compared with plain GAC, the fluoride adsorption capacity of this new adsorbent was improved and at least three times greater than that of uncoated GAC. The surface characteristics of coated GAC were observed with scanning electron microscopy. The surface area of the new adsorbent was calculated using the Brunauer-Emmett-Teller method. X-ray diffraction revealed that manganese oxides are amorphous. X-ray photoelectron spectroscopy demonstrated that manganese existed primarily in the oxidation state +IV. Kinetic and equilibrium adsorption data showed that the adsorption process follows the pseudo-second order kinetic and Freundlich equation models. The sorption data also indicated that the removal of fluoride by adsorption is a highly complex process, involving both boundary layer diffusion and intra-particle diffusion. The pH value of solution influences fluoride removal, and the optimum equilibrium pH value of fluoride adsorption is 3.0.

Recycling of the reduction sludge of manganese in the production of ceramics

International Nuclear Information System (INIS)

Castro, C.G.; Araujo, F.G.S.; Kruger, F.L.

2011-01-01

To study the use of manganese reduction residues, from the electric arc furnaces for the production of manganese ferro-alloys, as raw materials for construction bricks, different ceramic compositions were formulated with contents of 0, 2.5, 5 and 10wt% of waste addition to the clay used commercially, and sintered at different temperatures, 850, 950 and 1050°C. After firing, the ceramic samples were studied by optical microscopy, scanning electron microscopy (SEM), x-ray diffraction and by spectrophotometry. Their mechanical properties were evaluated by flexural strength, apparent porosity and specific mass, water absorption, linear shrinkage and loss on ignition. With the help of technics and experiment planning programs, the effects of the variables: temperature, composition and interaction between them over the results were discussed. This work proved that the addition of manganese reduction sludge to the clay, for the production of ceramic construction bricks, is highly feasible, from a technical standpoint. (author)

Effect of enhanced manganese oxidation in the hyporheic zone on basin-scale geochemical mass balance

Science.gov (United States)

Harvey, Judson W.; Fuller, Christopher C.

1998-01-01

We determined the role of the hyporheic zone (the subsurface zone where stream water and shallow groundwater mix) in enhancing microbially mediated oxidation of dissolved manganese (to form manganese precipitates) in a drainage basin contaminated by copper mining. The fate of manganese is of overall importance to water quality in Pinal Creek Basin, Arizona, because manganese reactions affect the transport of trace metals. The basin-scale role of the hyporheic zone is difficult to quantify because stream-tracer studies do not always reliably characterize the cumulative effects of the hyporheic zone. This study determined cumulative effects of hyporheic reactions in Pinal Creek basin by characterizing manganese uptake at several spatial scales (stream-reach scale, hyporheic-flow-path scale, and sediment-grain scale). At the stream-reach scale a one-dimensional stream-transport model (including storage zones to represent hyporheic flow paths) was used to determine a reach-averaged time constant for manganese uptake in hyporheic zones, 1/λs, of 1.3 hours, which was somewhat faster but still similar to manganese uptake time constants that were measured directly in centimeter-scale hyporheic flow paths (1/λh= 2.6 hours), and in laboratory batch experiments using streambed sediment (1/λ = 2.7 hours). The modeled depths of subsurface storage zones (ds = 4–17 cm) and modeled residence times of water in storage zones (ts = 3–12 min) were both consistent with direct measurements in hyporheic flow paths (dh = 0–15 cm, th = 1–25 min). There was also good agreement between reach-scale modeling and direct measurements of the percentage removal of dissolved manganese in hyporheic flow paths (fs = 8.9%, andfh = 9.3%rpar;. Manganese uptake experiments in the laboratory using sediment from Pinal Creek demonstrated (through comparison of poisoned and unpoisoned treatments) that the manganese removal process was enhanced by microbially mediated oxidation. The

Unusual stoichiometry control in the atomic layer deposition of manganese borate films from manganese bis(tris(pyrazolyl)borate) and ozone

International Nuclear Information System (INIS)

Klesko, Joseph P.; Bellow, James A.; Saly, Mark J.; Winter, Charles H.; Julin, Jaakko; Sajavaara, Timo

2016-01-01

The atomic layer deposition (ALD) of films with the approximate compositions Mn 3 (BO 3 ) 2 and CoB 2 O 4 is described using MnTp 2 or CoTp 2 [Tp = tris(pyrazolyl)borate] with ozone. The solid state decomposition temperatures of MnTp 2 and CoTp 2 are ∼370 and ∼340 °C, respectively. Preparative-scale sublimations of MnTp 2 and CoTp 2 at 210 °C/0.05 Torr afforded >99% recoveries with <0.1% nonvolatile residues. Self-limited ALD growth was demonstrated at 325 °C for MnTp 2 or CoTp 2 with ozone as the coreactant. The growth rate for the manganese borate process was 0.19 Å/cycle within the ALD window of 300–350 °C. The growth rate for the cobalt borate process was 0.39–0.42 Å/cycle at 325 °C. X-ray diffraction of the as-deposited films indicated that they were amorphous. Atomic force microscopy of 35–36 nm thick manganese borate films grown within the 300–350 °C ALD window showed root mean square surface roughnesses of 0.4–0.6 nm. Film stoichiometries were assessed by x-ray photoelectron spectroscopy and time of flight-elastic recoil detection analysis. The differing film stoichiometries obtained from the very similar precursors MnTp 2 and CoTp 2 are proposed to arise from the oxidizing ability of the intermediate high valent manganese oxide layers and lack thereof for cobalt.

Removal of iron and manganese using granular activated carbon and zeolite in artificial barrier of riverbank filtration

Science.gov (United States)

Ismail, Abustan; Harmuni, Halim; Mohd, Remy Rozainy M. A. Z.

2017-04-01

Iron and Manganese was examined from riverbank filtration (RBF) and river water in Sungai Kerian, Lubok Buntar, Serdang Kedah. Water from the RBF was influenced by geochemical and hydro chemical processes in the aquifer that made concentrations of iron (Fe), and manganese (Mn) high, and exceeded the standard values set by the Malaysia Ministry of Health. Therefore, in order to overcome the problem, the artificial barrier was proposed to improve the performance of the RBF. In this study, the capability and performance of granular activated carbon, zeolite and sand were investigated in this research. The effects of dosage, shaking speed, pH and contact time on removal of iron and manganese were studied to determine the best performance. For the removal of iron using granular activated carbon (GAC) and zeolite, the optimum contact time was at 2 hours with 200rpm shaking speed with 5g and 10g at pH 5 with percentage removal of iron was 87.81% and 83.20% respectively. The removal of manganese and zeolite arose sharply in 75 minutes with 90.21% removal, with 100rpm shaking speed. The GAC gave the best performance with 99.39% removal of manganese. The highest removal of manganese was achieved when the adsorbent dosage increased to 10g with shaking speed of 200rpm.

Research on a new oral contrast agent for abdominal MRI using free manganese ion

International Nuclear Information System (INIS)

Hasegawa, Hideo; Fujita, Osamu; Hiraishi, Kumiko; Narabayashi, Isamu; Komba, Toshinori; Hamamura, Yoshinori.

1996-01-01

Manganese chloride (Mn: 3 mg/100 g) aqueous solution with hydragenated oligosaccharide and xanthan gum (T 1 : 0.1 sec, T 2 : 0.03 sec at 0.5T) functions in gut as a positive contrast agent on MR T 1 -weighted images and a low signal component on MR T 2 -weighted images. The manganese in the solution functions as a contrast agent under free manganese ion (Mn 2+ ). Further, the solution has special characteristics in terms of MRI signal intensity and relaxation time that are equal to those of blueberry juice, which performs as an effective contrast agent on T 1 -and T 2 -weighted images, and functions as a contrast agent in vitro and in vivo. (author)

Magnetic properties and morphology of manganese ferrite nanoparticles in glasses

International Nuclear Information System (INIS)

Edelman, I; Ivanova, O; Ivantsov, I; Velikanov, D; Petrakovskaja, E; Artemenko, A; Curély, J; Kliava, J; Zaikovskiy, V; Stepanov, S

2011-01-01

Static magnetization (SM), magnetic circular dichroism (MCD) and electron magnetic resonance (EMR) studies are reported of borate glasses 22.5 K 2 O-22.5 Al 2 O 3 -55 B 2 O 3 co-doped with iron and manganese oxides. In as-prepared glasses the paramagnetic ions usually are in diluted state; however, if the ratio of the iron and manganese oxides in the charge is 3/2, magnetic nanoparticles are found already in as-prepared glass. After additional thermal treatment all glasses show magnetic behaviour, MCD and EMR due to the presence of magnetic nanoparticles with characteristics close to those of manganese ferrite. By computer simulating the EMR spectra at variable temperatures, their morphological characteristics are deduced: relatively broad size and shape distribution with average diameter of ca. 3-4 nm. The characteristic temperature-dependent shift of the apparent resonance field is explained by a strong temperature dependence of the magnetocrystalline anisotropy in the nanoparticles. The potassium-alumina-borate glasses containing magnetic nanoparticles represent a novel class of materials: t ransparent magnets . Indeed, they remain transparent in a part of visible and near infrared spectral range while showing magnetic and magneto-optical properties characteristic of magnetically ordered materials.

Removal of Sulphate and Manganese on Synthetic Wastewater in Sulphate Reducing Bioreactor Using Indonesian Natural Zeolite

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Endah Retnaningrum

2017-07-01

Full Text Available The present research was conducted to investigate sulphate and manganese removal from synthetic wastewater. The continuous laboratory scale of down-flow fluidized-bed reactor (DFBR using sulphate reducing bacteria (SRB consortium and Indonesian natural zeolite as a bacterial support material was designed. At 9 days operation, maximum sulphate and manganese removal was observed to be 23% and 15.4%, respectively. The pH values were also changed to neutral. The population of SRB increased which effect on the raising of their activity for removing sulphate and manganese. Using the scanning electronic microscopy (SEM, it was observed that natural zeolite possesses excellent physical characteristics as a bacterial support material in DFBR. The imaging SEM result of SRB consortium on zeolite surface clearly showed the developed SRB biofilm on that particle. Analysis result of EDX confirmed that manganese was precipitated as manganese–sulfides.

Arsenic, chromium, copper, iron, manganese, lead, selenium and ...

African Journals Online (AJOL)

2014-05-20

May 20, 2014 ... Arsenic, chromium, copper, iron, manganese, lead, selenium and zinc in the ... and sediment were collected and trace element concentrations were measured with an ICP-MS. ..... Clay minerals are known to have high sorption affinities ..... sediment/water quality interaction with particular reference to the.

Manganese-Oxygen Intermediates in O-O Bond Activation and Hydrogen-Atom Transfer Reactions.

Science.gov (United States)

Rice, Derek B; Massie, Allyssa A; Jackson, Timothy A

2017-11-21

Biological systems capitalize on the redox versatility of manganese to perform reactions involving dioxygen and its derivatives superoxide, hydrogen peroxide, and water. The reactions of manganese enzymes influence both human health and the global energy cycle. Important examples include the detoxification of reactive oxygen species by manganese superoxide dismutase, biosynthesis by manganese ribonucleotide reductase and manganese lipoxygenase, and water splitting by the oxygen-evolving complex of photosystem II. Although these enzymes perform very different reactions and employ structurally distinct active sites, manganese intermediates with peroxo, hydroxo, and oxo ligation are commonly proposed in catalytic mechanisms. These intermediates are also postulated in mechanisms of synthetic manganese oxidation catalysts, which are of interest due to the earth abundance of manganese. In this Account, we describe our recent efforts toward understanding O-O bond activation pathways of Mn III -peroxo adducts and hydrogen-atom transfer reactivity of Mn IV -oxo and Mn III -hydroxo complexes. In biological and synthetic catalysts, peroxomanganese intermediates are commonly proposed to decay by either Mn-O or O-O cleavage pathways, although it is often unclear how the local coordination environment influences the decay mechanism. To address this matter, we generated a variety of Mn III -peroxo adducts with varied ligand environments. Using parallel-mode EPR and Mn K-edge X-ray absorption techniques, the decay pathway of one Mn III -peroxo complex bearing a bulky macrocylic ligand was investigated. Unlike many Mn III -peroxo model complexes that decay to oxo-bridged-Mn III Mn IV dimers, decay of this Mn III -peroxo adduct yielded mononuclear Mn III -hydroxo and Mn IV -oxo products, potentially resulting from O-O bond activation of the Mn III -peroxo unit. These results highlight the role of ligand sterics in promoting the formation of mononuclear products and mark an important

Compositional changes of surface sediments and variability of manganese nodules in the Peru Basin

Science.gov (United States)

Marchig, Vesna; von Stackelberg, Ulrich; Hufnagel, Heinz; Durn, Goran

Two types of manganese nodules were observed in the Peru Basin: large botryoidal nodules in basins and small ellipsoidal nodules on slope positions. The sediment in areas with large botryoidal nodules contains a thinner and weaker oxidation zone than the sediment under small ellipsoidal nodules, indicating that diagenetic processes in the sediment, which supply manganese nodules with metals for their growth, are stronger in sediments on which large botryoidal nodules grow. Organic matter, which activates remobilization of metals, occurs mostly in the form of refractory lipidic compounds in the inner capsule of radiolaria. This material needs bacterial degradation to act as a reducing agent. Easily oxidizable organic components could not be found in the sediments. Other changes in sediment composition do not have a link to manganese nodule growth. Biogenous components (radiolarians, organogenic barite and apatite) increase towards the equatorial high-productivity zone. Authigenous clay minerals (nontronite as well as montmorillonite with high Fe +3 incorporation on positions of ochtaedral Al) increase with distance from the continent. The assessment of environmental impacts will have to take into account the regional differences in sediment composition and the small-scale variability of manganese nodules.

Manganese availability is negatively associated with carbon storage in northern coniferous forest humus layers.

Science.gov (United States)

Stendahl, Johan; Berg, Björn; Lindahl, Björn D

2017-11-14

Carbon sequestration below ground depends on organic matter input and decomposition, but regulatory bottlenecks remain unclear. The relative importance of plant production, climate and edaphic factors has to be elucidated to better predict carbon storage in forests. In Swedish forest soil inventory data from across the entire boreal latitudinal range (n = 2378), the concentration of exchangeable manganese was singled out as the strongest predictor (R 2  = 0.26) of carbon storage in the extensive organic horizon (mor layer), which accounts for one third of the total below ground carbon. In comparison, established ecosystem models applied on the same data have failed to predict carbon stocks (R 2  < 0.05), and in our study manganese availability overshadowed both litter production and climatic factors. We also identified exchangeable potassium as an additional strong predictor, however strongly correlated with manganese. The negative correlation between manganese and carbon highlights the importance of Mn-peroxidases in oxidative decomposition of recalcitrant organic matter. The results support the idea that the fungus-driven decomposition could be a critical factor regulating humus carbon accumulation in boreal forests, as Mn-peroxidases are specifically produced by basidiomycetes.

Determination of iron, copper, manganese and zinc in the soils, grapes and wines of the Azores

Directory of Open Access Journals (Sweden)

María Teresa Ribeiro de Lima

2004-06-01

Full Text Available This paper describes the determination of iron, copper, manganese and zinc in the soils, grapes and wines of the three viticultural regions of the Azores. Iron, copper and zinc were determined by flame atomic absorption spectrometry and manganese by graphite furnace atomic absorption. The concentrations of the four elements differed in soils of the three regions; there was no difference in the concentration in grapes, whereas significant differences were observed for the wines as regards the amounts of iron, manganese and zinc. The concentrations of these four elements in wine correspond with the mean values observed for other European regions.

Synthesis, characterization and photocatalytic activity of porous manganese oxide doped titania for toluene decomposition

International Nuclear Information System (INIS)

Jothiramalingam, R.; Wang, M.K.

2007-01-01

The present study describes the photocatalytic degradation of toluene in gas phase on different porous manganese oxide doped titanium dioxide. As synthesized birnessite and cryptomelane type porous manganese oxide were doped with titania and tested for photocatalytic decomposition of toluene in gas phase. The effects of the inlet concentration of toluene, flow rate (retention time) were examined and the relative humidity was maintained constantly. Thermal and textural characterization of manganese oxide doped titania materials were characterized by X-ray diffraction (XRD), thermogravemetry (TG), BET and TEM-EDAX studies. The aim of the present study is to synthesize the porous manganese oxide doped titania and to study its photocatalytic activity for toluene degradation in gas phase. Cryptomelane doped titania catalyst prepared in water medium [K-OMS-2 (W)] is shown the good toluene degradation with lower catalysts loading compared to commercial bulk titania in annular type photo reactor. The higher photocatalytic activity due to various factors such as catalyst preparation method, experimental conditions, catalyst loading, surface area, etc. In the present study manganese oxide OMS doped titania materials prepared by both aqueous and non-aqueous medium, aqueous medium prepared catalyst shows the good efficiency due to the presence of OH bonded groups on the surface of catalyst. The linear forms of different kinetic equations were applied to the adsorption data and their goodness of fit was evaluated based on the R 2 and standard error. The goodness to the linear fit was observed for Elovich model with high R 2 (≥0.9477) value

Bioleaching of copper, aluminum, magnesium and manganese from ...

African Journals Online (AJOL)

The present study was done to check the bioleaching feasibility of brown shale for the recovery of copper (Cu), aluminum (Al), magnesium (Mg) and manganese (Mn) ions using Ganoderma lucidum. Different experimental parameters were optimized for the enhanced recovery of metals ions. Effect of different substrates like ...

Measurement of the Effect of Phenothiazine on the Manganese Concentration in the Basal Ganglia of Sub-Human Primates by Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Bird, E. D.; Grant, L. G.; Ellis, W. H. [University of Florida, Gainesville, FL (United States)

1967-10-15

In man toxicity to manganese and phenothiazine drugs is manifested as dyskinesia. Cotzias and co-workers demonstrated that the phenothiazines form a semiquinone radical with manganese suggesting a common mechanism for production of Parkinsonism. Previous measurements of manganese have been made on whole brain. The very sensitive technique of activation analysis was used in the present study to measure manganese concentration in various nuclei of the basal ganglia. Phenothiazine was given to one group of Rhesus monkeys (Macaca mulatta) for one month. One group served as a control. After sacrifice the basal ganglia were dissected out with plastic knives, dried, and duplicate samples exposed to thermal neutrons at a flux of 1.35 x 10{sup 12} n/cm{sup 2}s. Manganese was separated radiochemical and counts under the manganese peak were compared to a standard handled identically. The results are presented. The manganese concentration was significantly increased in the putamen of primates receiving phenothiazine. There was no significant difference in the other nuclei examined. Phenothiazine is concentrated in basal ganglia. Dopamine is found in large quantities in caudate and putamen, and following phenothiazine therapy dopamine was found to be increased slightly. The associated increase of manganese and dopamine following phenothiazine provides some evidence that this drug causes profound biochemical alterations in the basal ganglia resulting in the various dyskinesias that are seen. (author)

Cytotoxicity and physicochemical characterization of iron–manganese-doped sulfated zirconia nanoparticles

Science.gov (United States)

Al-Fahdawi, Mohamed Qasim; Rasedee, Abdullah; Al-Qubaisi, Mothanna Sadiq; Alhassan, Fatah H; Rosli, Rozita; El Zowalaty, Mohamed Ezzat; Naadja, Seïf-Eddine; Webster, Thomas J; Taufiq-Yap, Yun Hin

2015-01-01

Iron–manganese-doped sulfated zirconia nanoparticles with both Lewis and Brønsted acidic sites were prepared by a hydrothermal impregnation method followed by calcination at 650°C for 5 hours, and their cytotoxicity properties against cancer cell lines were determined. The characterization was carried out using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brauner–Emmett–Teller (BET) surface area measurements, X-ray fluorescence, X-ray photoelectron spectroscopy, zeta size potential, and transmission electron microscopy (TEM). The cytotoxicity of iron–manganese-doped sulfated zirconia nanoparticles was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays against three human cancer cell lines (breast cancer MDA-MB231 cells, colon carcinoma HT29 cells, and hepatocellular carcinoma HepG2 cells) and two normal human cell lines (normal hepatocyte Chang cells and normal human umbilical vein endothelial cells [HUVECs]). The results suggest for the first time that iron–manganese-doped sulfated zirconia nanoparticles are cytotoxic to MDA-MB231 and HepG2 cancer cells but have less toxicity to HT29 and normal cells at concentrations from 7.8 μg/mL to 500 μg/mL. The morphology of the treated cells was also studied, and the results supported those from the cytotoxicity study in that the nanoparticle-treated HepG2 and MDA-MB231 cells had more dramatic changes in cell morphology than the HT29 cells. In this manner, this study provides the first evidence that iron–manganese-doped sulfated zirconia nanoparticles should be further studied for a wide range of cancer applications without detrimental effects on healthy cell functions. PMID:26425082

Influence of iron supply on toxic effects of manganese, molybdenum and vanadium on soybean, peas, and flax

Energy Technology Data Exchange (ETDEWEB)

Warington, K

1954-01-01

The investigations were carried out in nutrient solution with iron as ferric citrate and nitrogen in the form of nitrate. The addition of 2.5 ppm vanadium to plants in which iron chlorosis was already established, either by a lack of iron or by excess manganese, failed to counteract the condition, and caused toxic symptoms. The reduction of the standard iron supply to 1/2 or 1/3 accentuated the toxicity of 2.5 or 5 ppm V to soybean and flax, but a similar reduction in phosphorus had no influence. The toxicity to peas, however, was increased when the phosphorus was reduced to 1/10, provided the iron level was high (20 ppm Fe). Raising the iron supply to 20 or 30 ppm counteracted the toxicity of manganese (10 ppm), molybdenum (40 ppm) and vanadium (2.5 ppm), but the result was less marked when these three elements were combined. Iron supplied in successive, small doses proved less efficient in overcoming molybdenum or vanadium, but not manganese excess, than the same amount of iron supplied in fewer and larger quantities. Varying the iron supply had little effect when the concentration of the three elements was low. When increased iron supply had reduced the chlorosis caused by high manganese or vanadium, it also reduced the manganese and vanadium contents of the shoot (ppm/dm), but the molybdenum content was only lowered by high iron when given in non-toxic concentrations (0.1 ppm Mo) combined with excess manganese. Yield data for soybean and flax indicated an interaction between manganese with both molybdenum and vanadium if the iron supply was low, but none between molybdenum and vanadium. The effect of all three metals was additive in respect to iron.

Manganese concentration in the spinal cords and blood corpuscles of amyotrophic lateral sclerosis patients

Energy Technology Data Exchange (ETDEWEB)

Miyata, Satoru; Toyoshima, Masanori; Otsuki, Yuzo; Nagata, Hiroshi; Nakamura, Shigenobu (Kyoto Univ. (Japan). Faculty of Medicine)

1981-11-01

Manganese concentration in the spinal cord tissues and the blood corpuscles from patients with amyotrophic lateral sclerosis (ALS) and other diseases were measured by neutron activation analysis. The mean manganese concentration in the spinal cord from ALS patients was significantly higher than that from control subjects, especially in the anterior horn of the cervical cord. In order to determine the manganese concentration in blood corpuscles by neutron activation analysis, it was necessary to subtract /sup 56/Mn derived from the /sup 56/Fe(n, p)/sup 56/Mn reaction. The mean Mn concentration in the blood corpuscles from ALS patients seems to be lower than that from patients with other diseases. Fe, Se, Rb and Zn concentrations in the blood corpuscles from ALS patients were not different from those of patients with other diseases.

Manganese concentration in the spinal cords and blood corpuscles of amyotrophic lateral sclerosis patients

International Nuclear Information System (INIS)

Miyata, Satoru; Toyoshima, Masanori; Otsuki, Yuzo; Nagata, Hiroshi; Nakamura, Shigenobu

1981-01-01

Manganese concentration in the spinal cord tissues and the blood corpuscles from patients with amyotrophic lateral sclerosis (ALS) and other diseases were measured by neutron activation analysis. The mean manganese concentration in the spinal cord from ALS patients was significantly higher than that from control subjects, especially in the anterior horn of the cervical cord. In order to determine the manganese concentration in blood corpuscles by neutron activation analysis, it was necessary to subtract 56 Mn derived from the 56 Fe(n, p) 56 Mn reaction. The mean Mn concentration in the blood corpuscles from ALS patients seems to be lower than that from patients with other diseases. Fe, Se, Rb and Zn concentrations in the blood corpuscles from ALS patients were not different from those of patients with other diseases. (author)

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

International Nuclear Information System (INIS)

Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2010-01-01

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 μg 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.

By lithology Zbruch deposits (Lower Sarmatian Nikopol manganese ore Basin

Directory of Open Access Journals (Sweden)

Bogdanovich V.V.

2010-06-01

Full Text Available Based on lithologic-paleogeographic study Zbruch layers of Nikopol manganese ore Basin sediments described lithological and genetic types of rocks and facies conditions of formation of deposits.

Noncollinear cluster ferromagnetism in manganite-lanthanum perovskites in manganese abundance

International Nuclear Information System (INIS)

Zubov, Eh.E.; D'yakonov, V.P.; Szymczak, H.

2002-01-01

The theoretical substantiation of the noncollinear spin structure realization in the weakly doped subsystem on the LaMnO 3 basis, which is observed in the compounds with the manganese abundance (La 1-y Ca y ) 1-x Mn 1+x O 3 , where y = 0.03 and x = 0-0.4, is carried out. It is shown experimentally, that the samples with x > 0.1 manifest anomalous magnetization at T 200 E increases. It is assumed, that this is connected with origination of the sloped phase in the clusters of the manganese heterovalent ions. It is shown, that the account for the spin quanta properties leads to essential modification of the thermodynamic behavior of the magnetic with collectivized electrons [ru

Fabrication of ultrafine manganese oxide-decorated carbon nanofibers for high-performance electrochemical capacitors

Energy Technology Data Exchange (ETDEWEB)

Yang, Ying; Lee, Sungsik; Brown, Dennis E.; Zhao, Hairui; Li, Xinsong; Jiang, Daqiang; Hao, Shijie; Zhao, Yongxiang; Cong, Daoyong; Zhang, Xin; Ren, Yang

2016-09-01

Ultrafine manganese oxide-decorated carbon nanofibers (MnOn-CNF) as a new type of electrode materials are facilely fabricated by direct conversion of Mn, Zn-trimesic acid (H3BTC) metal organic framework fibers (Mn-ZnBTC). The construction and evolution of Mn-ZnBTC precursors are investigated by SEM and in situ high-energy XRD. The manganese oxides are highly dispersed onto the porous carbon nanofibers formed simultaneously, verified by TEM, X-ray absorption fine structure (XAFS), Raman, ICP-AES and N2 adsorption techniques. As expected, the resulting MnOn-CNF composites are highly stable, and can be cycled up to 5000 times with a high capacitance retention ratio of 98% in electrochemical capacitor measurements. They show a high capacitance of up to 179 F g–1 per mass of the composite electrode, and a remarkable capacitance of up to 18290 F g–1 per active mass of the manganese(IV) oxide, significantly exceeding the theoretical specific capacitance of manganese(IV) oxide (1370 F g–1). The maximum energy density is up to 19.7 Wh kg–1 at the current density of 0.25 A g–1, even orders higher than those of reported electric double-layer capacitors and pseudocapacitors. The excellent capacitive performance can be ascribed to the joint effect of easy accessibility, high porosity, tight contact and superior conductivity integrated in final MnOn-CNF composites.

Unusual stoichiometry control in the atomic layer deposition of manganese borate films from manganese bis(tris(pyrazolyl)borate) and ozone

Energy Technology Data Exchange (ETDEWEB)

Klesko, Joseph P.; Bellow, James A.; Saly, Mark J.; Winter, Charles H., E-mail: chw@chem.wayne.edu [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States); Julin, Jaakko; Sajavaara, Timo [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland)

2016-09-15

The atomic layer deposition (ALD) of films with the approximate compositions Mn{sub 3}(BO{sub 3}){sub 2} and CoB{sub 2}O{sub 4} is described using MnTp{sub 2} or CoTp{sub 2} [Tp = tris(pyrazolyl)borate] with ozone. The solid state decomposition temperatures of MnTp{sub 2} and CoTp{sub 2} are ∼370 and ∼340 °C, respectively. Preparative-scale sublimations of MnTp{sub 2} and CoTp{sub 2} at 210 °C/0.05 Torr afforded >99% recoveries with <0.1% nonvolatile residues. Self-limited ALD growth was demonstrated at 325 °C for MnTp{sub 2} or CoTp{sub 2} with ozone as the coreactant. The growth rate for the manganese borate process was 0.19 Å/cycle within the ALD window of 300–350 °C. The growth rate for the cobalt borate process was 0.39–0.42 Å/cycle at 325 °C. X-ray diffraction of the as-deposited films indicated that they were amorphous. Atomic force microscopy of 35–36 nm thick manganese borate films grown within the 300–350 °C ALD window showed root mean square surface roughnesses of 0.4–0.6 nm. Film stoichiometries were assessed by x-ray photoelectron spectroscopy and time of flight-elastic recoil detection analysis. The differing film stoichiometries obtained from the very similar precursors MnTp{sub 2} and CoTp{sub 2} are proposed to arise from the oxidizing ability of the intermediate high valent manganese oxide layers and lack thereof for cobalt.

Removal of 54Mn from the mouse body by dilution with stable manganese and by chelation with DTPA

International Nuclear Information System (INIS)

Sato, Itaru; Matsusaka, Naonori; Tsuda, Shuji

1999-01-01

54 Mn is one of the activation products generated in nuclear reactors. This study was carried out to find a method appropriate for the removal of 54 Mn. Intraperitoneal administration of stable manganese effectively promoted the excretion of 54 Mn from the mouse body. The efficacy for removing 54 Mn was estimated to be 56, 67, 77 and 82% for manganese doses of 0.3, 1, 3 and 10 mg/kg, respectively. Oral administration of stable manganese was also effective for the removal of 54 Mn, but the efficacy was inferior to that obtained by intraperitoneal administration because of low gastrointestinal absorption of manganese. Ca-DTPA and Zn-DTPA promoted the excretion of 54 Mn when administered 1 h after administration of 54 Mn, but these chelating agents had little effect when administered after 3 h or more. Zn-DTPA was less effective than Ca-DTPA. These results demonstrate that dilution with stable manganese is more effective than chelation with DTPA for the removal of 54 Mn from the body. (author)

Experimental and numerical simulation of carbon manganese steel ...

African Journals Online (AJOL)

Experimental and numerical simulation of carbon manganese steel for cyclic plastic behaviour. J Shit, S Dhar, S Acharyya. Abstract. The paper deals with finite element modeling of saturated low cycle fatigue and the cyclic hardening phenomena of the materials Sa333 grade 6 carbon steel and SS316 stainless steel.

Manganese Biogeochemistry in a Central Czech Republic Catchment

Czech Academy of Sciences Publication Activity Database

Navrátil, Tomáš; Shanley, J. B.; Krám, P.; Mihaljevič, M.; Drahota, Petr

2007-01-01

Roč. 186, 1-4 (2007), s. 149-165 ISSN 0049-6979 R&D Projects: GA ČR GA205/04/0060 Institutional research plan: CEZ:AV0Z30130516 Keywords : manganese * catchment * weathering * biogeochemistry * biotite weathering * forest ecosystem * mass balance Subject RIV: DD - Geochemistry Impact factor: 1.224, year: 2007

Manganese nodules in the Exclusive Economic Zone of Mauritius

Digital Repository Service at National Institute of Oceanography (India)

Nath, B.N.; ShyamPrasad, M.

The distribution of manganese nodules in the Exclusive Economic Zone of the island nation Mauritius was delineated during cruise SK-35 of ORV Sagar Kanya in 1987. The areas surveyed included Saya de Malha and Nazareth Banks, the Cargados Carajos...

40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Manganese heterocyclic tetraamine complex (generic). 721.10003 Section 721.10003 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... section. (2) The significant new uses are: (i) Industrial, commercial, and consumer activities...

Porous nickel hydroxide-manganese dioxide-reduced graphene oxide ternary hybrid spheres as excellent supercapacitor electrode materials.

Science.gov (United States)

Chen, Hao; Zhou, Shuxue; Wu, Limin

2014-06-11

This paper reports the first nickel hydroxide-manganese dioxide-reduced graphene oxide (Ni(OH)2-MnO2-RGO) ternary hybrid sphere powders as supercapacitor electrode materials. Due to the abundant porous nanostructure, relatively high specific surface area, well-defined spherical morphology, and the synergetic effect of Ni(OH)2, MnO2, and RGO, the electrodes with the as-obtained Ni(OH)2-MnO2-RGO ternary hybrid spheres as active materials exhibited significantly enhanced specific capacitance (1985 F·g(-1)) and energy density (54.0 Wh·kg(-1)), based on the total mass of active materials. In addition, the Ni(OH)2-MnO2-RGO hybrid spheres-based asymmetric supercapacitor also showed satisfying energy density and electrochemical cycling stability.

Bacterial Disproportionation of Elemental Sulfur Coupled to Chemical Reduction of Iron or Manganese

Science.gov (United States)

Thamdrup, Bo; Finster, Kai; Hansen, Jens Würgler; Bak, Friedhelm

1993-01-01

A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S0) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S0 was microbially disproportionated to sulfate and sulfide, as follows: 4S0 + 4H2O → SO42- + 3H2S + 2H+. Subsequent chemical reactions between the formed sulfide and the added FeOOH led to the observed precipitation of iron sulfides. Sulfate and iron sulfides were also produced when FeOOH was replaced by FeCO3. Further enrichment with manganese oxide, MnO2, instead of FeOOH yielded stable cultures which formed sulfate during concomitant reduction of MnO2 to Mn2+. Growth of small rod-shaped bacteria was observed. When incubated without MnO2, the culture did not grow but produced small amounts of SO42- and H2S at a ratio of 1:3, indicating again a disproportionation of S0. The observed microbial disproportionation of S0 only proceeds significantly in the presence of sulfide-scavenging agents such as iron and manganese compounds. The population density of bacteria capable of S0 disproportionation in the presence of FeOOH or MnO2 was high, > 104 cm-3 in coastal sediments. The metabolism offers an explanation for recent observations of anaerobic sulfide oxidation to sulfate in anoxic sediments. PMID:16348835

HDM model magnet mechanical behavior with high manganese steel collars

International Nuclear Information System (INIS)

Snyder, J.R.

1994-01-01

Westinghouse Electric Corporation (WEC) is presently under contract to the SSCL to design, develop, fabricate, and deliver superconducting dipole magnets for the High Energy Booster (HEB). As a first step toward these objectives SSCL supplied a design for short model magnets of 1.8 m in length (DSB). This design was used as a developmental tool for all phases of engineering and fabrication. Mechanical analysis of the HDM (High Energy Booster Dipole Magnets) model magnet design as specified by SSCL was performed with the following objectives: (1) to develop a thorough understanding of the design; (2) to review and verify through analytical and numerical analyses the SSCL model magnet design; (3) to identify any deficiencies that would violate design parameters specified in the HDM Design Requirements Document. A detailed analysis of the model magnet mechanical behavior was pursued by constructing a quarter section finite element model and solving with the ANSYS finite element code. Collar materials of Nitronic-40 and High-Manganese steel were both considered for the HEB model magnet program with the High-Manganese being the final selection. The primary mechanical difference in the two materials is the much lower thermal contraction of the High-Manganese steel. With this material the collars will contract less than the enclosing yoke producing an increased collar yoke interference during cooldown

Concentrations of chromium, manganese, and lead in air and in avian eggs

International Nuclear Information System (INIS)

Hui, C.A.

2002-01-01

Embryo exposure was not directly related to tropospheric levels of chromium, manganese or lead. - The expansion of urbanization introduces air pollution to wildlife areas. Some metal contaminants occurring in concentrations too small to have any measurable impact on adult birds may seriously affect embryos that are more sensitive to contaminants than the adult. Chromium, manganese, and lead are toxic and can be passed from the hen to the egg. This study relates the concentrations of these metals in eggs to their concentrations in air in three cities. Rock dove eggs were sampled and air pollution records were examined in the California cities of Riverside, Los Angeles, and San Francisco. The eggs from San Francisco did not differ from those of Los Angeles in lead concentration but the air did differ. The eggs collected in Los Angeles in 1998 had concentrations of chromium greater than in those from Riverside and from Los Angeles 1999 but the air had concentrations of chromium that did not differ among those three collections. Concentrations of manganese did not differ among the eggs but did differ among the air samples of the three cities. Exposures of embryos to chromium and manganese in this study were not at levels warranting concern. Although the concentration at which lead in eggs impairs avian health is not established, the highest concentrations found in this study exceed estimated safe concentrations. There is no indication that embryo exposure is directly related to atmospheric levels of these metals in the cities of this study

Activity and selectivity of manganese oxides in alcohols Conversion as influenced by gamma-irradiation

International Nuclear Information System (INIS)

Doheim, M.M.; Ahmed, A.S.; El-Shobaky, G.A.

2002-01-01

Manganese oxide samples obtained from thermal decomposition of manganese carbonate at 400 and 600 deg C were subjected to different doses of g-irradiation within the range 0.2 to 1.6 MGy. The surface and catalytic properties of the above samples were studied using nitrogen adsorption isotherms measured at -196 deg C and catalytic conversion of ethanol and isopropanol at 300-400 deg C using micropulse technique. The results obtained revealed that manganese oxides obtained at 400 deg C consisted of a mixture of Mn 2 O 3 and MnO 2 while the samples calcined at 600 deg C composed entirely of Mn 2 O 3 . Gamma-irradiation resulted in a decrease in the particle size of manganese oxide phases with subsequent increase in their specific surface areas. Gamma-irradiation with 0.2 and 0.8 MGy effected a measurable progressive decrease in the catalytic activity in dehydration and dehydrogenation of both alcohols. However, the treated catalyst retained their initial activity upon exposure to a dose of 1.6 MGy. Also, g-irradiation increased the selectivities of the investigated solids towards dehydrogenation of both alcohols. The catalyst samples precalcined at 600 deg C exhibited higher catalytic activities than those precalcined at 400 deg C. (author)

Matrix effects on the determination of manganese in geological materials by atomic-absorption spectrophotometry under different flame conditions

Science.gov (United States)

Sanzolone, R.F.; Chao, T.T.

1978-01-01

Suppression caused by five of the seven matrix elements studied (Si, Al, Fe, Ca and Mg) was observed in the atomic-absorption determination of manganese in geological materials, when synthetic solutions and the recommended oxidizing air-acetylene flame were used. The magnitude of the suppression effects depends on (1) the kind and concentration of the interfering elements, (2) the type of acid medium, and (3) the concentration of manganese to be determined. All interferences noted are removed or alleviated by using a reducing nitrous oxide-acetylene flame. The atomic-absorption method using this flame can be applied to the determination of total and extractable manganese in a wide range of geological materials without interferences. Analyses of six U.S. Geological Survey rock standards for manganese gave results in agreement with the reported values. ?? 1978.

Uranium in Pacific deep-sea sediments and manganese nodules

International Nuclear Information System (INIS)

Kunzendorf, H.; Plueger, W.L.; Friedrich, G.H.

1983-01-01

A total of 1344 manganese nodules and 187 pelagic sediments from 9 areas in the North and the South Pacific were analyzed for U by the delayed-neutron counting technique. A strong positive correlation between U and Fe in nodules and sediments suggests a co-precipitative removal from sea water into the Fe-rich (ferromanganese mineral phase MnO 2 . Enrichment of U and Fe in nodules from the northwestern slopes of two submarine hills (U between 6 and 9 ppm) in the equatorial nodule belt is thought to be caused by directional bottom water flow creating elevated oxygenized conditions in areas opposed to the flow. Economically important nodule deposits from the nodule belt and the Peru Basin have generally low U contents, between 3 and 5 ppm. Insignificant resources of U of about 4 x 10 5 in the Pacific manganese nodules are estimated. (orig.)

Molecular Interactions of Plutonium(VI) with Synthetic Manganese-Substituted Goethite

Energy Technology Data Exchange (ETDEWEB)

Hu, Yung-Jin; Schwaiger, Luna Kestrel; Booth, Corwin H.; Kukkadapu, Ravi K.; Cristiano, Elena; Kaplan, Daniel; Nitsche, Heino

2010-03-09

Plutonium(VI) sorption on the surface of well-characterized synthetic manganese-substituted goethite minerals (Fe1-xMnxOOH) was studied using X-ray absorption spectroscopy. We chose to study the influence of manganese as a minor component in goethite, because goethite rarely exists as a pure phase in nature. Manganese X-ray absorption near-edge structure measurements indicated that essentially all the Mn in the goethite existed as Mn(III), even though Mn was added during mineral synthesis as Mn(II). Importantly, energy dispersive X-ray analysis demonstrated that Mn did not exist as discrete phases and that it was homogeneously mixed into the goethite to within the limit of detection of the method. Furthermore, Mössbauer spectra demonstrated that all Fe existed as Fe(III), with no Fe(II) present. Plutonium(VI) sorption experiments were conducted open to air and no attempt was made to exclude carbonate. The use of X-ray absorption spectroscopy allows us to directly and unambiguously measure the oxidation state of plutonium in situ at the mineral surface. Plutonium X-ray absorption near-edge structure measurements carried out on these samples showed that Pu(VI) was reduced to Pu(IV) upon contact with the mineral. This reduction appears to be strongly correlated with mineral solution pH, coinciding with pH transitions across the point of zero charge of the mineral. Furthermore, extended X-ray absorption fine structure measurements show evidence of direct plutonium binding to the metal surface as an inner-sphere complex. This combination of extensive mineral characterization and advanced spectroscopy suggests that sorption of the plutonium onto the surface of the mineral was followed by reduction of the plutonium at the surface of the mineral to form an inner-sphere complex. Because manganese is often found in the environment as a minor component associated with major mineral components, such as goethite, understanding the molecular-level interactions of plutonium with

Population structure of manganese-oxidizing bacteria in stratified soils and properties of manganese oxide aggregates under manganese-complex medium enrichment.

Directory of Open Access Journals (Sweden)

Weihong Yang

Full Text Available Manganese-oxidizing bacteria in the aquatic environment have been comprehensively investigated. However, little information is available about the distribution and biogeochemical significance of these bacteria in terrestrial soil environments. In this study, stratified soils were initially examined to investigate the community structure and diversity of manganese-oxidizing bacteria. Total 344 culturable bacterial isolates from all substrata exhibited Mn(II-oxidizing activities at the range of 1 µM to 240 µM of the equivalent MnO2. The high Mn(II-oxidizing isolates (>50 mM MnO2 were identified as the species of phyla Actinobacteria, Firmicutes and Proteobacteria. Seven novel Mn(II-oxidizing bacterial genera (species, namely, Escherichia, Agromyces, Cellulomonas, Cupriavidus, Microbacterium, Ralstonia, and Variovorax, were revealed via comparative phylogenetic analysis. Moreover, an increase in the diversity of soil bacterial community was observed after the combined enrichment of Mn(II and carbon-rich complex. The phylogenetic classification of the enriched bacteria represented by predominant denaturing gradient gel electrophoresis bands, was apparently similar to culturable Mn(II-oxidizing bacteria. The experiments were further undertaken to investigate the properties of the Mn oxide aggregates formed by the bacterial isolates with high Mn(II-oxidizing activity. Results showed that these bacteria were closely encrusted with their Mn oxides and formed regular microspherical aggregates under prolonged Mn(II and carbon-rich medium enrichment for three weeks. The biotic oxidation of Mn(II to Mn(III/IV by these isolates was confirmed by kinetic examinations. X-ray diffraction assays showed the characteristic peaks of several Mn oxides and rhodochrosite from these aggregates. Leucoberbelin blue tests also verified the Mn(II-oxidizing activity of these aggregates. These results demonstrated that Mn oxides were formed at certain amounts under the

Nuclear orientation studies of manganese in copper Kondo system

International Nuclear Information System (INIS)

Bakalyar, D.

1977-08-01

The internal field seen by the 54 Mn nuclei in a dilute (about 1 part per billion) manganese in copper Kondo system was measured using nuclear orientation. The measurements were made at temperatures on the order of 4 mK in applied fields of 5 kG to 40 kG. Temperatures were measured using a 60 Co in nickel nuclear orientation thermometer and were achieved by adiabatically demagnetizing an ingot of the hyperfine enhanced nuclear coolant PrCu 6 from temperatures of about 30 mK (the mixing chamber temperature of a dilution refrigerator). The data was temperature independent but there was evidence of iteractions between the manganese atoms at manganese concentrations of 1 / 2 part per million. The data was interpreted by assuming that the internal field consisted of the hyperfine field minus the applied field (i.e. the hyperfine field and applied field were aligned in opposite directions). The hyperfine field versus applied field data was compared to three approximate solutions to the Kondo Hamiltonian. Two of the solutions, one by Luther and Emery and the other by Goetze and Schlottmann, fit the data very well. The third solution, that proposed by Ishii, does not fit the data. Fitted to the data, the Luther-Emery solution predicts a saturation value of the hyperfine field of 303 kG whereas the Goetze-Schlottmann solution predicts a saturation value of 297 kG. The hyperfine field is only beginning to reach its saturation value with applied fields of 40 kG

Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution

Directory of Open Access Journals (Sweden)

Francesco Ferella

2010-01-01

Full Text Available The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a 24 full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature 40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 g L-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution.

Tensile behavior of irradiated manganese-stabilized stainless steel

Energy Technology Data Exchange (ETDEWEB)

Klueh, R.L. [Oak Ridge National Lab., TN (United States)

1996-10-01

Tensile tests were conducted on seven experimental, high-manganese austenitic stainless steels after irradiation up to 44 dpa in the FFTF. An Fe-20Mn-12Cr-0.25C base composition was used, to which various combinations of Ti, W, V, B, and P were added to improve strength. Nominal amounts added were 0.1% Ti, 1% W, 0.1% V, 0.005% B, and 0.03% P. Irradiation was carried out at 420, 520, and 600{degrees}C on the steels in the solution-annealed and 20% cold-worked conditions. Tensile tests were conducted at the irradiation temperature. Results were compared with type 316 SS. Neutron irradiation hardened all of the solution-annealed steels at 420, 520, and 600{degrees}C, as measured by the increase in yield stress and ultimate tensile strength. The steel to which all five elements were added to the base composition showed the least amount of hardening. It also showed a smaller loss of ductility (uniform and total elongation) than the other steels. The total and uniform elongations of this steel after irradiation at 420{degrees}C was over four times that of the other manganese-stabilized steels and 316 SS. There was much less difference in strength and ductility at the two higher irradiation temperatures, where there was considerably less hardening, and thus, less loss of ductility. In the cold-worked condition, hardening occured only after irradiation at 420{degrees}C, and there was much less difference in the properties of the steels after irradiation. At the 420{degrees}C irradiation temperature, most of the manganese-stabilized steels maintained more ductility than the 316 SS. After irradiation at 420{degrees}C, the temperature of maximum hardening, the steel to which all five of the elements were added had the best uniform elongation.

Development of an accelerator based system for in vivo neutron activation analysis measurements of manganese in humans

Science.gov (United States)

Arnold, Michelle Lynn

2001-11-01

Manganese is required by the human body, but as with many heavy elements, in large amounts it can be toxic, producing a neurological disorder similar to that of Parkinson's Disease. The primary industrial uses of the element are for the manufacturing of steel and alkali batteries. Environmental exposure may occur via drinking water or exhaust emissions from vehicles using gasoline with the manganese containing compound MMT as an antiknock agent (MMT has been approved for use in both Canada and the United States). Preclinical symptoms of toxicity have recently been detected in individuals occupationally exposed to airborne manganese at levels below the present threshold limit value set by the EPA. Evidence also suggests that early detection of manganese toxicity is crucial since once the symptoms have developed past a certain point, the syndrome will continue to progress even if manganese exposure ceases. The development of a system for in vivo neutron activation analysis (IVNAA) measurement of manganese levels was investigated, with the goal being to have a means of monitoring both over exposed and manganese deficient populations. The McMaster KN-accelerator was used to provide low-energy neutrons, activation within an irradiation site occurred via the 55Mn(n,gamma) 56Mn capture reaction, and the 847 keV gamma-rays emitted when 56Mn decayed were measured using one or more Nal(TI) detectors. The present data regarding manganese metabolism and storage within the body are limited, and it is unclear what the optimal measurement site would be to provide a suitable biomarker of past exposure. Therefore the feasibility of IVNAA measurements in three sites was examined---the liver, brain and hand bones. Calibration curves were derived, minimum detectable limits determined and resulting doses calculated for each site (experimentally in the case of the liver and hand bones, and through computer simulations for the brain). Detailed analytical calculations of the 7Li(p,n) 7Be

Comparison of tolerance to soil acidity among crop plants. II. Tolerance to high levels of aluminum and manganese. Comparative plant nutrition

Energy Technology Data Exchange (ETDEWEB)

Tanaka, A; Hayakawa, Y

1975-01-01

Research was conducted by growing various species of plants in solutions containing high concentrations of manganese or aluminum. A comparison was made of the tolerance of these plants to low pH and to the manganese and aluminum. In addition, the element content of the plants was compared. Plants high in calcium were found to have an intermediate tolerance to high concentrations of manganese and aluminum. Gramineae had a high tolerance to these elements and to low pH. They also accumulated high levels of these elements. Legumes had a high tolerance to manganese and aluminum and to low pH. However, they also accumulated high levels of these elements. Legumes had a high tolerance to manganese and aluminum and to low pH. However, they also accumulated high levels of these elements. Cruciferae had a low tolerance to the elements and to low pH. They contained low levels of manganese and aluminum. Chenopodiaceae had a low tolerance to the elements as well as low element contents. However, they were highly tolerant to low pH.

INFLUENCE OF BIOLOGICAL AND THERMAL TRANSFORMED SEWAGE SLUDGE APPLICATION ON MANGANESE CONTENT IN PLANTS AND SOIL

Directory of Open Access Journals (Sweden)

Małgorzata Koncewicz-Baran

2014-10-01

Full Text Available A great variety of sewage sludge treatment methods, due to the agent (chemical, biological, thermal leads to the formation of varying ‘products’ properties, including the content of heavy metals forms. The aim of the study was to determine the effects of biologically and thermally transformed sewage sludge on the manganese content in plants and form of this element in the soil. The study was based on a two-year pot experiment. In this study was used stabilized sewage sludge collected from Wastewater Treatment Plant Krakow – ”Płaszów” and its mixtures with wheat straw in the gravimetric ratio 1:1 in conversion to material dry matter, transformed biologically (composting by 117 days in a bioreactor and thermally (in the furnace chamber with no air access by the following procedure exposed to temperatures of 130 °C for 40 min → 200 °C for 30 min. In both years of the study biologically and thermally transformed mixtures of sewage sludge with wheat straw demonstrated similar impact on the amount of biomass plants to the pig manure. Bigger amounts of manganese were assessed in oat biomass than in spring rape biomass. The applied sewage sludge and its biologically and thermally converted mixtures did not significantly affect manganese content in plant biomass in comparison with the farmyard manure. The applied fertilization did not modify the values of translocation and bioaccumulation ratios of manganese in the above-ground parts and roots of spring rape and oat. No increase in the content of the available to plants forms of manganese in the soil after applying biologically and thermally transformed sewage sludge mixtures with straw was detected. In the second year, lower contents of these manganese forms were noted in the soil of all objects compared with the first year of the experiment.

Catalytic Role of Manganese Oxides in Prebiotic Nucleobases Synthesis from Formamide.

Science.gov (United States)

Bhushan, Brij; Nayak, Arunima; Kamaluddin

2016-06-01

Origin of life processes might have begun with the formation of important biomonomers, such as amino acids and nucleotides, from simple molecules present in the prebiotic environment and their subsequent condensation to biopolymers. While studying the prebiotic synthesis of naturally occurring purine and pyrimidine derivatives from formamide, the manganese oxides demonstrated not only good binding for formamide but demonstrated novel catalytic activity. A novel one pot manganese oxide catalyzed synthesis of pyrimidine nucleobases like thymine is reported along with the formation of other nucleobases like purine, 9-(hydroxyacetyl) purine, cytosine, 4(3 H)-pyrimidinone and adenine in acceptable amounts. The work reported is significant in the sense that the synthesis of thymine has exhibited difficulties especially under one pot conditions and also such has been reported only under the catalytic activity of TiO2. The lower oxides of manganese were reported to show higher potential as catalysts and their existence were favored by the reducing atmospheric conditions prevalent on early Earth; thereby confirming the hypothesis that mineral having metals in reduced form might have been more active during the course of chemical evolution. Our results further confirm the role of formamide as a probable precursor for the formation of purine and pyrimidine bases during the course of chemical evolution and origin of life.

Manganese toxicity with ephedrone abuse manifesting as parkinsonism: a case report

LENUS (Irish Health Repository)

Iqbal, Mudassir

2012-02-07

Abstract Introduction Neurologic consequences of manganese toxicity have been recognized since 1837. A new form of presumed manganese poisoning has been reported in drug-addicted persons from Eastern Europe and the Baltic states who have intravenously injected self-prepared methcathinone hydrochloride (ephedrone), which is synthesized from pseudoephedrine hydrochloride using potassium permanganate as a potent oxidant. This clinical syndrome is under-recognized in Western Europe and there are no reported cases in the literature from Ireland. Case presentation We report a 30-year-old Eastern European man who presented with a two-year history of gait disturbance. A neurological assessment revealed features of parkinsonism which included hypophonia, hypomimia, mild bradykinesia and rigidity with no resting tremor. He held his arms slightly abducted from his sides when walking, with a reduction in arm swing. Magnetic resonance imaging of his brain showed a high signal on T1 in the globus pallidus and serum manganese levels were raised. He had no response to levodopa. Conclusion Manganism secondary to ephedrone abuse causing parkinsonism has emerged in Western Europe in recent years due to mass immigration and often remains unrecognized. This paper highlights the various features of this rare cause of parkinsonism and aids in its recognition and subsequent diagnosis. Neurologists in Western Europe will increasingly encounter such patients.

Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems

DEFF Research Database (Denmark)

Berg, Björn; Erhagen, Björn; Johansson, Maj-Britt

2015-01-01

We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same lit...

Decline of General Intelligence in Children Exposed to Manganese from Mining Contamination in Puyango River Basin, Southern Ecuador.

Science.gov (United States)

Betancourt, Óscar; Tapia, Marlene; Méndez, Ignacio

2015-09-01

Based on ecosystem approaches to health (Ecohealth), this study sought to identify neurobehavioral disorders in children exposed to several levels of toxic metal pollution from gold mining in the Puyango River Basin, Southern Ecuador. Ninety-three children born or living in the study area participated in the study. A neurobehavioral test battery consisting of 12 tests assessing various functions of the nervous system was applied as well as a questionnaire regarding events of exposure of children's mothers to contaminants during perinatal period. Hair samples were taken from children to determine manganese concentrations. Descriptive and inferential statistics were applied in order to examine possible relationships between exposure events, hair manganese, and neurobehavioral disorders. Having controlled co-variables such as age and educational level, it was found that children with elevated levels of hair manganese (over 2 μg/g) had poor performance in the test of general intelligence (Raven's Progressive Color Matrices Scale PCM). The Ecohealth approach helped to identify that children in the lower Puyango Basin with very elevated levels of manganese in the river water (970 µg/L) are the ones who have the highest levels of hair manganese and the worst performance in the intelligence test.

Attenuation capability of low activation-modified high manganese austenitic stainless steel for fusion reactor system

Energy Technology Data Exchange (ETDEWEB)

Eissa, M.M. [Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Helwan (Egypt); El-kameesy, S.U.; El-Fiki, S.A. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt); Ghali, S.N. [Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Helwan (Egypt); El Shazly, R.M. [Physics Department, Faculty of Science, Al-Azhar University, Cairo (Egypt); Saeed, Aly, E-mail: aly_8h@yahoo.com [Nuclear Power station Department, Faculty of Engineering, Egyptian-Russian University, Cairo (Egypt)

2016-11-15

Highlights: • Improvement stainless steel alloys to be used in fusion reactors. • Structural, mechanical, attenuation properties of investigated alloys were studied. • Good agreement between experimental and calculated results has been achieved. • The developed alloys could be considered as candidate materials for fusion reactors. - Abstract: Low nickel-high manganese austenitic stainless steel alloys, SSMn9Ni and SSMn10Ni, were developed to use as a shielding material in fusion reactor system. A standard austenitic stainless steel SS316L was prepared and studied as a reference sample. The microstructure properties of the present stainless steel alloys were investigated using Schaeffler diagram, optical microscopy, and X-ray diffraction pattern. Mainly, an austenite phase was observed for the prepared stainless steel alloys. Additionally, a small ferrite phase was observed in SS316L and SSMn10Ni samples. The mechanical properties of the prepared alloys were studied using Vickers hardness and tensile tests at room temperature. The studied manganese stainless steel alloys showed higher hardness, yield strength, and ultimate tensile strength than SS316L. On the other hand, the manganese stainless steel elongation had relatively lower values than the standard SS316L. The removal cross section for both slow and total slow (primary and those slowed down in sample) neutrons were carried out using {sup 241}Am-Be neutron source. Gamma ray attenuation parameters were carried out for different gamma ray energy lines which emitted from {sup 60}Co and {sup 232}Th radioactive sources. The developed manganese stainless steel alloys had a higher total slow removal cross section than SS316L. While the slow neutron and gamma rays were nearly the same for all studied stainless steel alloys. From the obtained results, the developed manganese stainless steel alloys could be considered as candidate materials for fusion reactor system with low activation based on the short life

Determination of rare-earth elements, yttrium and scandium in manganese nodules by inductively-coupled argon-plastma emission spectrometry

Science.gov (United States)

Fries, T.; Lamothe, P.J.; Pesek, J.J.

1984-01-01

A sequential-scanning, inductively-coupled argon plasma emission spectrometer is used for the determination of the rare-earth elements, plus yttrium and scandium, in manganese nodules. Wavelength selection is optimized to minimize spectral interferences from manganese nodule components. Samples are decomposed with mixed acids in a sealed polycarbonate vessel, and elements are quantified without further treatment. Results for U.S. Geological Survey manganese nodule standards A-1 and P-1 had average relative standard deviations of 6.8% and 8.1%, respectively, and results were in good agreement with those obtained by other methods. ?? 1984.

Manganese Exposure in the General Population in a Mining District ...

International Development Research Centre (IDRC) Digital Library (Canada)

Manganese Exposure in the General Population in a Mining District (Mexico) ... in a population living close to a mine and mineral processing plant in Mexico ... Call for proposals: Innovations for the economic inclusion of marginalized youth.

Production of manganese peroxidase by white rot fungi from potato ...

African Journals Online (AJOL)

PRECIOUS

2010-01-18

Jan 18, 2010 ... production rate of the MnP using the potato-processing wastewater-based medium were higher (ca. 2.5- ... Ligninolytic enzymes, such as manganese peroxidase ... not currently reached industrial levels except for the laccase.

India's manganese nodule mine site in the Central Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Banakar, V.K.

This commentary highlights the activities of massive exploration programme for manganese nodule deposits in the Central Indian Basin located 5 km below the ocean surface and India's claim for mine site development and registration with UNCLOS...

IMPACTS OF ROAD DE-ICING SALTS ON MANGANESE TRANSPORT TO GROUNDWATER IN ROADSIDE SOILS

OpenAIRE

Wen, Yingrong

2012-01-01

Manganese (Mn) is an important element in soil, it occur natural in minerals and precipitated as Mn-oxides. Several factors could decide the solubility and mobility of Mn in soil water. In this study, the impact of road de-icing salts (NaCl) on manganese mobilization and transport to groundwater in roadside soils has been investigated by leaching tests. Generally, in the salt solution leachates, the water-soluble concentrations of Mn tended to increase with elevated salt concentrations, sugge...

Adsorption Study of Electric Arc Furnace Slag for the Removal of Manganese from Solution

OpenAIRE

C. L. Beh; Luqman Chuah; Thomas S.Y. Choong; Mohd. Z.B. Kamarudzaman; Khalina Abdan

2010-01-01

Problem statement: Steel making slag from Electric Arc Furnace (EAF) is an abundant by-product in Malaysia steel making industry. It has potential to be used for heavy metal removal from contaminated water or waste water. Approach: The aim of this study was to investigate the characteristic and behavior of manganese removal by using EAF slag for efficient metal removal. The removal characteristics of manganese were investigated in term of sorption kinetics and isotherm. The batch adsorption k...

Selection of organic acid leaching reagent for recovery of zinc and manganese from zinc-carbon and alkaline spent batteries

Science.gov (United States)

Yuliusman; Amiliana, R. A.; Wulandari, P. T.; Ramadhan, I. T.; Kusumadewi, F. A.

2018-03-01

Zinc-carbon and alkaline batteries are often used in electronic equipment that requires small quantities of power. The waste from these batteries contains valuable metals, such as zinc and manganese, that are needed in many industries and can pollute the environment if not treated properly. This paper concerns the recovery of zinc and manganese metals from zinc-carbon and alkaline spent batteries with leaching method and using organic acid as the environmental friendly leaching reagent. Three different organic acids, namely citric acid, malic acid and aspartic acid, were used as leaching reagents and compared with sulfuric acid as non-organic acid reagents that often used for leaching. The presence of hydrogen peroxide as manganese reducers was investigated for both organic and non-organic leaching reagents. The result showed that citric acid can recover 64.37% Zinc and 51.32% Manganese, while malic acid and aspartic acid could recover less than these. Hydrogen peroxide gave the significant effect for leaching manganese with non-organic acid, but not with organic acid.

Investigation of paramagnetic saturation in lanthanum manganese nitrate

NARCIS (Netherlands)

Flokstra, Jakob; Meijer, H.C.; Bots, G.J.C.; Verheij, W.A.; van der Marel, L.C.

1973-01-01

Paramagnetic saturation of lanthanum manganese nitrate, La2Mn3(NO3)12·24H2O, has been investigated at liquid He temperatures in a static as well as a dynamical way. With the aid of the molecular-field theory the Casimir and Du Pré dispersion and absorption curves are adapted explicitly to the

Assessment of Serum Levels of Magnesium and Manganese among ...

African Journals Online (AJOL)

Pregnant women in developing countries have been reported to consume diets with low density of minerals and essential trace elements. Therefore, this study aims to assess the serum levels of magnesium and manganese and its trimester correlates among pregnant women in Ika community of Delta state, Nigeria.

Adsorptive removal of manganese, arsenic and iron from groundwater

NARCIS (Netherlands)

Buamah, R.

2009-01-01

To determine the scale of the problem of arsenic, iron and manganese contamination of groundwater in Ghana a survey was performed in the first phase of the research to provide in depth information with respect to these contaminants. Presence of these mentioned contaminants in groundwater is not

Manganese deficiency in plants

DEFF Research Database (Denmark)

Schmidt, Sidsel Birkelund; Jensen, Poul Erik; Husted, Søren

2016-01-01

Manganese (Mn) is an essential plant micronutrient with an indispensable function as a catalyst in the oxygen-evolving complex (OEC) of photosystem II (PSII). Even so, Mn deficiency frequently occurs without visual leaf symptoms, thereby masking the distribution and dimension of the problem...... restricting crop productivity in many places of the world. Hence, timely alleviation of latent Mn deficiency is a challenge in promoting plant growth and quality. We describe here the key mechanisms of Mn deficiency in plants by focusing on the impact of Mn on PSII stability and functionality. We also address...... the mechanisms underlying the differential tolerance towards Mn deficiency observed among plant genotypes, which enable Mn-efficient plants to grow on marginal land with poor Mn availability....

Relationship between anti-oxidant capacity and manganese accumulation in the soft tissues of two freshwater molluscs: Unio pictorum mancus (Lamellibranchia, Unionidae and Viviparus ater (Gastropoda, Prosobranchia

Directory of Open Access Journals (Sweden)

Oscar RAVERA

2005-08-01

Full Text Available Manganese is an element of great importance in the life cycle of plants and animals. For example, it plays an essential role as an activator of various enzymatic systems such as isoenzymes of superoxide dismutase. Freshwater Unionidae concentrate relatively large amounts of manganese in their tissues, but little is known about the physiological role of this metal. The aim of this research is to acquire a better knowledge of the role of manganese in molluscs which accumulate large amounts of this metal and in those with low manganese concentrations. As manganese is one of the metals present in the superoxide molecule, the possible relationship between manganese concentration in the soft tissues of molluscs and the antioxidant capacity of the metal can usefully be tested. To this end two species of molluscs were analysed: Unio pictorum mancus (Lamellibranchia, Unionidae, which is very rich in manganese, and Viviparus ater (Gastropoda, Prosobranchia which has a low manganese content. The adults of both species were analysed for manganese concentration by ICP, and for antioxidant capacity as RAC (Relative Antioxidant Capacity by a superoxide dismutase method. The results clearly demonstrate the active role played by manganese against free radicals and consequently the important role of the metal in protecting Unio against oxidative stress. The low concentration of manganese in Viviparus may be the result of the effective excretion of this metal, as was found for ruthenium.

Manganese oxidation by bacterial isolates from the Indian Ridge System

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, S.O.; Krishnan, K.P.; Khedekar, V.D.; LokaBharathi, P.A.

The abundance and activity of culturable manganese-oxidizing bacteria were assessed from near-bottom water samples of the tectonically active Carlsberg Ridge. Retrievable counts as colony forming units (CFU) on dilute nutrient agar medium (dilNA = 2...

Assessment of exposure to manganese in welding operations during the assembly of heavy excavation machinery accessories.

Science.gov (United States)

Smargiassi, A; Baldwin, M; Savard, S; Kennedy, G; Mergler, D; Zayed, J

2000-10-01

Welder exposure to metals in various industrial sectors is poorly characterized. We had the opportunity to carry out an exploratory study to characterize manganese exposure in welding operations in a recently established Quebec factory that assembled accessories for heavy excavation machinery. Ten workers were sampled for total manganese for at least two consecutive days out of three followed by two consecutive days for respirable manganese (with a size selective sampler with a median cut-off of 4 microns), during a typical week in the summer of 1998. Parts being welded were characterized as large or small. Small parts were those being welded on tables during subassembly. Workers were divided into two groups according to the parts they were welding. Seventy-eight percent of the total manganese exposure levels of welding operations during the assembly of large accessories of heavy excavation machinery exceeded the manganese American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 0.20 mg/m3 (GM 0.24 mg/m3, n = 14) while none exceeded the TLV during the assembly of small pieces (GM 0.06 mg/m3, n = 8). Welding operations during the assembly of large heavy excavation machinery accessories may pose a significant health hazard. Considering the importance of task-related variables affecting exposure among workers, further studies are needed to better characterize exposure determinants of welding operations during the assembly of heavy excavation machinery accessories.

A two-generation inhalation reproductive toxicity study upon the exposure to manganese chloride.

Science.gov (United States)

McGough, Doreen; Jardine, Lynne

2017-01-01

A number of published studies have suggested that high levels of exposure to manganese, especially those found in occupational settings, can adversely affect the reproductive system. The objective of this study was therefore to investigate if these findings can be replicated using the Sprague Dawley rat and, if so, to identify those parts of the reproductive system are more susceptible. Male and female rats were exposed to manganese dichloride (MnCl 2 ) via inhalation at concentrations of 0 (air-control); 5, 10 and 20μg/L air over 10 weeks (F0) and over 11 weeks (F1) prior to mating, and then throughout mating, gestation and lactation until termination after the F1 and F2 generation had reached Day 21 of lactation respectively. Animals were monitored for clinical signs of toxicity and for effects on body weight, food consumption, effects on the entire reproductive system including maternal care. The offspring were monitored for survival and growth up to weaning. Blood samples were taken from all adult animals for bioanalytical of manganese analysis prior to dosing, prior to mating and prior to weaning/necropsy. There were no deaths related to treatment, though respiratory tract effects were observed in F0 animals in the mid and high dose animals. Body weight and food consumption were affected at high dose in both generation. There were no treatment-related effects on the oestrous cycles, mating performance, sexual maturity, fertility or duration of gestation or litter size, the sperm motility, count of morphology (sperm) or the ovary follicle scoring in either generation. The No Observed Effect Level (NOEL) for reproductive performance was considered to be the target dose level of 20μg/L. Based on these findings, manganese chloride could not be considered a reprotoxicant under these conditions of exposure. Therefore, soluble and insoluble forms of inorganic manganese compounds by extrapolation cannot be considered as reprotoxicants. Copyright © 2016 Elsevier B

Magnetocaloric properties of manganese(III) porphyrins bearing 2,6-di-tert-butylphenol groups

Energy Technology Data Exchange (ETDEWEB)

Korolev, V.V., E-mail: vvk@isc-ras.ru [G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya str., 1, Ivanovo 153045 (Russian Federation); Lomova, T.N.; Maslennikova, A.N.; Korolev, D.V. [G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya str., 1, Ivanovo 153045 (Russian Federation); Shpakovsky, D.B.; Zhang, Jianwei; Milaeva, E.R. [Lomonosov Moscow State University, Department of Medicinal Chemistry and Fine Organic Synthesis, Moscow 119991 (Russian Federation)

2016-03-01

Magnetocaloric effect (MCE) and heat capacity during the magnetization of (5,10,15,20-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato) manganese (III) chloride (1), (5-(4-hydroxyphenyl)-10,15,20-tris(3,5-di-tert-butyl-4-hydroxyphenyl) porphynato) manganese (III) chloride (2), and (5-(4-palmitoyloxyphenyl)-10,15,20-tris(3,5-di-tert-butyl-4-hydroxyphenyl) porphynato) manganese (III) chloride (3) in their aqueous suspensions were determined by the microcalorimetric method over the temperature range of 278–320 K and in magnetic fields from 0 to 1 T. MCE was positive for all complexes studied, i.e. the magnetic field impression under adiabatic conditions led to an increase in temperature of the complexes suspensions. MCE increased with an increase in the magnetic field induction at all temperatures studied. Dependences of MCE on temperature had weak maxima at 298 K at all magnetic induction values. The disturbance of the intermolecular hydrogen-bonding of hydroxyl groups is one of probable reasons for such dependences type. MCE values increased under the palmitoyl substituent incorporation into one of the phenol groups at all temperatures. The heat capacity of the studied complexes rose slightly with temperature growth. Dependences of the heat capacity on temperature showed that the magnetic component of the heat capacity did not appear due to the presence of the manganese atom acting as a paramagnetic center in complexes 1, 2, and 3. The relation between the complexes structure and their magnetothermal properties was analyzed. It was justified that the changes of magnetothermal properties were caused by electronic substitution effects and, to an even greater degree, by the conditions of intermolecular hydrogen bonds formation in the paramagnetic materials. - Highlights: • The magnetocaloric effect and heat capacity of 3 manganese porphyrin were determined. • Temperature dependences of magnetocaloric effect has been studied. • The relation between the

In Situ Atom Probe Deintercalation of Lithium-Manganese-Oxide.

Science.gov (United States)

Pfeiffer, Björn; Maier, Johannes; Arlt, Jonas; Nowak, Carsten

2017-04-01

Atom probe tomography is routinely used for the characterization of materials microstructures, usually assuming that the microstructure is unaltered by the analysis. When analyzing ionic conductors, however, gradients in the chemical potential and the electric field penetrating dielectric atom probe specimens can cause significant ionic mobility. Although ionic mobility is undesirable when aiming for materials characterization, it offers a strategy to manipulate materials directly in situ in the atom probe. Here, we present experimental results on the analysis of the ionic conductor lithium-manganese-oxide with different atom probe techniques. We demonstrate that, at a temperature of 30 K, characterization of the materials microstructure is possible without measurable Li mobility. Also, we show that at 298 K the material can be deintercalated, in situ in the atom probe, without changing the manganese-oxide host structure. Combining in situ atom probe deintercalation and subsequent conventional characterization, we demonstrate a new methodological approach to study ionic conductors even in early stages of deintercalation.

The Wear Characteristics of Heat Treated Manganese Phosphate Coating Applied to AlSi D2 Steel with Oil Lubricant

Directory of Open Access Journals (Sweden)

Venkatesan Alankaram

2012-12-01

Full Text Available Today, in the area of material design conversion coatings play an important role in the applications where temperature, corrosion, oxidation and wear come in to play. Wear of metals occurs when relative motion between counter-surfaces takes place, leading to physical or chemical destruction of the original top layers. In this study, the tribological behaviour of heat treated Manganese phosphate coatings on AISI D2 steel with oil lubricant was investigated. The Surface morphology of manganese phosphate coatings was examined by Scanning Electron Microscope (SEM and Energy Dispersive X-ray Spectroscopy (EDX .The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The wear resistance of the coated steel was evaluated through pin on disc test using a sliding velocity of 3.0m/s under Constant loads of 40 N and 100 N with in controlled condition of temperature and humidity. The Coefficient of friction and wear rate were evaluated. Wear pattern of Manganese phosphate coated pins with oil lubricant, Heat treated Manganese phosphate coated pins with oil lubricant were captured using Scanning Electron Microscope (SEM. The results of the wear test established that the heat treated manganese phosphate coating with oil lubricant exhibited the lowest average coefficient of friction and the lowest wear loss up to 6583 m sliding distance under 40 N load and 3000 m sliding distance even under 100 N load respectively. The Wear volume and temperature rise in heat treated Manganese Phosphate coated pins with oil lubricant is lesser than the Manganese Phosphate coated pins with oil lubricant

Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

Science.gov (United States)

Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

1996-01-01

An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

Synthesis of electro-active manganese oxide thin films by plasma enhanced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Merritt, Anna R. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States); Rajagopalan, Ramakrishnan [Department of Engineering, The Pennsylvania State University, Dubois, PA 15801 (United States); Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Carter, Joshua D. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States)

2014-04-01

The good stability, cyclability and high specific capacitance of manganese oxide (MnO{sub x}) has recently promoted a growing interest in utilizing MnO{sub x} in asymmetric supercapacitor electrodes. Several literature reports have indicated that thin film geometries of MnO{sub x} provide specific capacitances that are much higher than bulk MnO{sub x} powders. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique for the production of metal oxide thin films with high purity and controllable thickness. In this work, MnO{sub x} thin films deposited by PECVD from a methylcyclopentadienyl manganese tricarbonyl precursor are presented and the effect of processing conditions on the quality of MnO{sub x} films is described. The film purity and oxidation state of the MnO{sub x} films were studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Preliminary electrochemical testing of MnO{sub x} films deposited on carbon fiber electrodes in aqueous electrolytes indicates that the PECVD synthesized films are electrochemically active. - Highlights: • Plasma enhanced chemical vapor deposition of manganese oxide thin films. • Higher plasma power and chamber pressure increase deposition rate. • Manganese oxide thin films are electrochemically active. • Best electrochemical performance observed for pure film with low stress • Lower capacitance observed at higher scan rates despite thin film geometry.

Manganese oxalate nanorods as ballistic modifier for composite solid propellants

Energy Technology Data Exchange (ETDEWEB)

Singh, Supriya [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India); Chawla, Mohit [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Siril, Prem Felix, E-mail: prem@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Singh, Gurdip [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India)

2014-12-10

Highlights: • Manganese oxalate nanorods were prepared using mild thermal precipitation and aging. • The nanorods were found to be efficient ballistic modifier for solid propellants. • The nanorods sensitized the thermolysis of ammonium perchlorate. • Controlled thermal decomposition of nanorods yielded manganese oxide nanoparticles. • MnO nanoparticles formed insitu in the condensed phase enhance the burning rates. - Abstract: Rod-shaped nanostructures of manganese oxalate (MnC{sub 2}O{sub 4}) were synthesized via mild thermal precipitation and aging process. Chemical composition of the MnC{sub 2}O{sub 4} nanorods was confirmed using Fourier transform infra-red (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) and selected area electron diffraction (SAED) studies revealed the crystal structure. Field emission scanning electron microscopy (FE-SEM) imaging and high resolution transmission electron microscopy (HR-TEM) were employed to study the structural features of the nanorods. The MnC{sub 2}O{sub 4} nanorods were found to be efficient ballistic modifier for the burning rate enhancement of composite solid propellants (CSPs). Thermal analysis using TGA-DSC showed that MnC{sub 2}O{sub 4} nanorods sensitized the thermal decomposition of ammonium perchlorate (AP) and the CSPs. Controlled thermal decomposition of the MnC{sub 2}O{sub 4} nanorods resulted in the formation of managanese oxide nanoparticles with mesoporosity. A plausible mechanism for the burning rate enhancement using MnC{sub 2}O{sub 4} nanorods was proposed.

Laser microstructuring and annealing processes for lithium manganese oxide cathodes

International Nuclear Information System (INIS)

Proell, J.; Kohler, R.; Torge, M.; Ulrich, S.; Ziebert, C.; Bruns, M.; Seifert, H.J.; Pfleging, W.

2011-01-01

It is expected that cathodes for lithium-ion batteries (LIB) composed out of nano-composite materials lead to an increase in power density of the LIB due to large electrochemically active surface areas but cathodes made of lithium manganese oxides (Li-Mn-O) suffer from structural instabilities due to their sensitivity to the average manganese oxidation state. Therefore, thin films in the Li-Mn-O system were synthesized by non-reactive radiofrequency magnetron sputtering of a spinel lithium manganese oxide target. For the enhancement of the power density and cycle stability, large area direct laser patterning using UV-laser radiation with a wavelength of 248 nm was performed. Subsequent laser annealing processes were investigated in a second step in order to set up a spinel-like phase using 940 nm laser radiation at a temperature of 680 deg. C. The interaction processes between UV-laser radiation and the material was investigated using laser ablation inductively coupled plasma mass spectroscopy. The changes in phase, structure and grain shape of the thin films due to the annealing process were recorded using Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The structured cathodes were cycled using standard electrolyte and a metallic lithium anode. Different surface structures were investigated and a significant increase in cycling stability was found. Surface chemistry of an as-deposited as well as an electrochemically cycled thin film was investigated via X-ray photoelectron spectroscopy.

Biomimetic oxidation of carbamazepine with hydrogen peroxide catalyzed by a manganese porphyrin

Directory of Open Access Journals (Sweden)

Cláudia M. B. Neves

2012-01-01

Full Text Available This laboratory project is planned for an undergraduate chemistry laboratory in which students prepare a manganese porphyrin able to mimic the oxidative metabolism of carbamazepine, one of the most frequently prescribed drugs in the treatment of epilepsy. The in vitro oxidation of carbamazepine results in the formation of the corresponding 10,11-epoxide, the main in vivo metabolite. The reaction is catalyzed by manganese porphyrin in the presence of H2O2, an environmentally-friendly oxidant. Through this project students will develop their skills in organic synthesis, coordination chemistry, chromatographic techniques such as TLC and HPLC, UV-visible spectrophotometry, and NMR spectroscopy.

Biomimetic oxidation of carbamazepine with hydrogen peroxide catalyzed by a manganese porphyrin

Energy Technology Data Exchange (ETDEWEB)

Neves, Claudia M.B.; Simoes, Mario M.Q.; Domingues, Fernando M.J.; Neves, M. Graca P.M.S.; Cavaleiro, Jose A.S., E-mail: msimoes@ua.pt [Dept. de Quimica, QOPNA, Universidade de Aveiro (Portugal)

2012-07-01

This laboratory project is planned for an undergraduate chemistry laboratory in which students prepare a manganese porphyrin able to mimic the oxidative metabolism of carbamazepine, one of the most frequently prescribed drugs in the treatment of epilepsy. The in vitro oxidation of carbamazepine results in the formation of the corresponding 10,11-epoxide, the main in vivo metabolite. The reaction is catalyzed by manganese porphyrin in the presence of H{sub 2}O{sub 2}, an environmentally-friendly oxidant. Through this project students will develop their skills in organic synthesis, coordination chemistry, chromatographic techniques such as TLC and HPLC, UV-visible spectrophotometry, and NMR spectroscopy. (author)

Carbon/manganese oxide based fuel cell electrocatalyst using "Flywheel" principle

Czech Academy of Sciences Publication Activity Database

Vondrák, Jiří; Klápště, Břetislav; Velická, Jana; Sedlaříková, M.; Novák, V.; Reiter, Jakub

2005-01-01

Roč. 8, č. 1 (2005), s. 1-4 ISSN 1480-2422 Institutional research plan: CEZ:AV0Z40320502 Keywords : manganese oxide * oxygen electrode * bifunctional electrode Subject RIV: CA - Inorganic Chemistry Impact factor: 0.772, year: 2005

Study on the manganese distribution in the soil of an agricultural field using neutron activation analysis method

International Nuclear Information System (INIS)

Souza, Marcos P. de; Armelin, Maria J.A.; Cruvinel, Paulo E.

1997-01-01

Manganese distribution in the soil of an agricultural field was evaluated by neutron activation analysis. The accuracy and precision of the method were verified by the analysis of two Standard Reference Materials with different manganese concentration in the experimental field, through one schematic diagram. (author). 7 refs., 1 fig., 2 tabs

Iron and manganese removal from drinking water

Directory of Open Access Journals (Sweden)

Daniela-Elena Pascu

2016-04-01

Full Text Available The purpose of the present study is to find a suitable method for removal of iron and manganese from ground water, considering bothlocal economical and environmental aspects. Ground water is a highly important source of drinking water in Romania. Ground water is naturally pure from bacteria at a 25 m depth or more. However, solved metals may occur and if the levels are too high, the water is not drinkable. Different processes, such as electrochemical and combined electrochemical-adsorption methods have been applied to determine metals content in accordance to reports of National Water Agency from Romania (ANAR. Every water source contains dissolved or particulate compounds. The concentrations of these compounds can affect health, productivity, compliance requirements, or serviceability and cannot be economically removed by conventional filtration means. In this study, we made a comparison between the electrochemical and adsorption methods (using membranes. Both methods have been used to evaluate the efficiency of iron and manganese removal at various times and temperatures. We used two membrane types: composite and cellulose, respectively. Different approaches, including lowering the initial current density and increasing the initial pH were applied. Reaction kinetics was achieved using mathematical models: Jura and Temkin.

Microbially mediated redox transformations of manganese (II) along with some other trace elements: a study from Antarctic lakes

Digital Repository Service at National Institute of Oceanography (India)

Krishnan, K.P.; Sinha, R.K.; Krishna, K.; Nair, S.; Singh, S.M.

a study that was conducted in the brackish water lakes in the Larsemann Hills region (east Antarctica) is presented. The rate of in situ manganese oxidation ranged from 0.04 to 3.96 ppb day sup(-1). These lakes harbor numerous manganese-oxidizing...

Multiple-targeted graphene-based nanocarrier for intracellular imaging of mRNAs

International Nuclear Information System (INIS)

Wang, Ying; Li, Zhaohui; Liu, Misha; Xu, Jinjin; Hu, Dehong; Lin, Yuehe; Li, Jinghong

2017-01-01

Simultaneous detection and imaging of multiple intracellular messenger RNA (mRNAs) hold great significant for early cancer diagnostics and preventive medicine development. Herein, we propose a multiple-targeted graphene oxide (GO) nanocarrier that can simultaneously detect and image different type mRNAs in living cells. First of all, in vitro detection of multiple targets have been realized successfully based on the multiple-targeted GO nanocarrier with linear relationship ranging from 3 nM to 200 nM, as well as sensitive detection limit of 1.84 nM for manganese superoxide dismutase (Mn-SOD) mRNA and 2.45 nM for β-actin mRNA. Additionally, this nanosensing platform composed of fluorescent labelled single strand DNA probes and GO nanocarrier can identify Mn-SOD mRNA and endogenous mRNA of β-actin in living cancer cells, showing rapid response, high specificity, nuclease stability, and good biocompatibility during the cell imaging. Thirdly, changes of the expression levels of mRNA in living cells before or after the drug treatment can be monitored successfully. By using multiple ssDNA as probes and GO nanocarrier as the cellular delivery cargo, the proposed simultaneous multiple-targeted sensing platform will be of great potential as a powerful tool for intracellular trafficking process from basic research to clinical diagnosis. - Graphical abstract: Schematic illustration of simultaneously multiple mRNAs monitoring inside single living breast cancer cell based on GO nanocarrier. In particular, the fluorescent signals could be monitored when Mn-SOD probe (red) and β-actin probe (green) hybridizes with their mRNA targets inside the living cells. Random probe (orange) was regarded as control probe for the sensing strategy. - Highlights: • A multiple-targeted GO nanocarrier was used for mRNAs imaging and expression changes after drug treatment can be monitored successfully. • Sensitive detection limit of 1.84 nM for manganese superoxide dismutase (Mn-SOD) m

Adsorption of manganese(II) ions by EDTA-treated activated carbons

Energy Technology Data Exchange (ETDEWEB)

Khan, A.Y.; Mazyck, D.W. [Jones Edmunds & Associates, Gainesville, FL (United States)

2009-07-01

The adsorption of manganese(II) ions from aqueous solution onto three different granular activated carbons treated with ethylenediamine tetraacetic acid (EDTA) and its sodium salt was investigated. Characterization of the chelate-treated carbons showed that EDTA altered the physical and chemical properties of the sorbents relative to their untreated counterparts. Furthermore, the modified sorbents exhibited a heightened capacity towards the adsorption of Mn(II) ions from aqueous media. Manganese(II) ion removal increased from 0 to 6.5 mg/g for the lignite coal-based sorbent, from 3.5 to 14.7 mg/g for the wood-based sorbent and from 1.3 to 7.9 mg/g for the bituminous coal-based sorbent. The increased removal is attributed, in part, to the creation of Lewis base sites that participate in covalent interactions and hydrolysis reactions.

Manganese oxide nanowires, films, and membranes and methods of making

Science.gov (United States)

Suib, Steven Lawrence [Storrs, CT; Yuan, Jikang [Storrs, CT

2008-10-21

Nanowires, films, and membranes comprising ordered porous manganese oxide-based octahedral molecular sieves, and methods of making, are disclosed. A single crystal ultra-long nanowire includes an ordered porous manganese oxide-based octahedral molecular sieve, and has an average length greater than about 10 micrometers and an average diameter of about 5 nanometers to about 100 nanometers. A film comprises a microporous network comprising a plurality of single crystal nanowires in the form of a layer, wherein a plurality of layers is stacked on a surface of a substrate, wherein the nanowires of each layer are substantially axially aligned. A free standing membrane comprises a microporous network comprising a plurality of single crystal nanowires in the form of a layer, wherein a plurality of layers is aggregately stacked, and wherein the nanowires of each layer are substantially axially aligned.

Fundamental study of manganese dioxide for catalytic recombustion of exhaust gas of motor car

Energy Technology Data Exchange (ETDEWEB)

Shimoyamada, T

1974-01-01

The catalytic activities of five manganese dioxide preparations were tested in a pulse reactor to assess their carbon monoxide-oxidizing capability in relation to the catalytic afterburning of automobile exhaust gases. Catalysts prepared from manganese sulfate showed diminished catalytic activity as a result of sulfate poisoning. Higher oxidation activity was obtained with a catalyst prepared by precipitating the permanganate salt in acidic solution. Two forms of carbon monoxide adsorption were demonstrated, each with a characteristic activation energy and reaction temperature.

Manganese Catalyzed α-Olefination of Nitriles by Primary Alcohols.

Science.gov (United States)

Chakraborty, Subrata; Das, Uttam Kumar; Ben-David, Yehoshoa; Milstein, David

2017-08-30

Catalytic α-olefination of nitriles using primary alcohols, via dehydrogenative coupling of alcohols with nitriles, is presented. The reaction is catalyzed by a pincer complex of an earth-abundant metal (manganese), in the absence of any additives, base, or hydrogen acceptor, liberating dihydrogen and water as the only byproducts.

Investigation of thermo luminesce properties of calcium chloride doped with manganese

International Nuclear Information System (INIS)

Farag, H.

1999-01-01

Thermoluminescence (TL) properties of calcium chloride doped with manganese (CaCI: Mn) have been investigated. Three thermoluminescence peaks were detected, where the prominent TL-peak appeared at 210 degree. TL response had a linear relation from 0.36 cGy up to 400cGy. The ratio between the sensitivity of calcium chloride: Mn and LiF-700 was found to be 1.42. The TL fading was studied by applying different annealing temperatures. The TL residual percentage was found to be 0.023% for 300degree annealing temperature after 50 min of annealing time. Fading was not observed for the sample, which was stored at room temperature. Calcium chloride doped with manganese could be used as personal radiation detector.

The effect of manganese content on mechanical properties of high titanium microalloyed steels

Energy Technology Data Exchange (ETDEWEB)

Li, Xiaolin, E-mail: lixiaolinwork@163.com [Shougang Research Institute of Technology, Beijing 100041 (China); Li, Fei; Cui, Yang; Xiao, Baoliang [Shougang Research Institute of Technology, Beijing 100041 (China); Wang, Xuemin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

2016-11-20

In this work, in order to achieve an optimum combination of high strength, ductility and toughness of high Ti microalloyed steel, extensive research efforts were exerted to study the effect of soaking temperature, manganese and sulfur content on properties of titanium steels. Precipitation hardening of Ti-bearing steels has been found to vary with different soaking temperature. Higher strength was achieved in these steels at higher soaking temperature due to dissolution of more TiC, Ti{sub 4}S{sub 2}C{sub 2} and little TiN, which lead to re-precipitation of fine carbides with greater volume fraction. The results of transmission electron microscope (TEM)analysis indicates that there were more and finer TiC precipitates coherent or semi-coherent with the ferrite matrix in the high manganese content steel than in low manganese content steel. The marked improvement in strength is also associated with low sulfur content. TiC particles smaller than 20 nm in 8Ti-8Mn steel help enhance strength to higher than 302 MPa compared with 8Mn steel.

The Efficacy of Syzygium aromaticum Essential Oil in Cognitive Disorders against Manganese Chronic Exposure in Rats during Development

Directory of Open Access Journals (Sweden)

Djallal Eddine Houari ADLI

2014-06-01

Full Text Available The essential oil of Syzygium aromaticum has been widely used in traditional medicine to treat a variety of diseases, including some neurological disorders. This study aims at testing, in vivo, the possible anxiolytic and antidepressant effects, of the Syzygium aromaticum essential oil against chronic manganese chloride (4.79 mg/l intoxication during the gestation and lactation period, in Wistar rat pups. Wistar rat pups were exposed to manganese via their dams’ drinking water from postnatal day (PND 1 to (PND 21. After their weaning, the rats exposed to manganese received injections of essential oil of Syzygium aromaticum (0.1 ml/kg for 18 days. The level of anxiety, depression and locomotor activity were studied. Locomotor activity (open field test, anxiety (elevated plus maze tests, and depression (forced swimming test were evaluated. The results of the present study indicate that Manganese exposure induces, on the one hand, impairments of body (p<0.001 and of brain weight (p<0.05. On the other hand, it increases level of anxiety (p<0.05, depression (p<0.001 and locomotor hyporactivity (p<0.001, when compared to control rats. Administration of essential oil of Syzygium aromaticum leads to a reduction in the level of anxiety (p<0.05, of depression (p<0.001 and corrects locomotor hyporactivity (p<0.05 in rats exposed to manganese beforehand. These results suggest that essential oil of Syzygium aromaticum can employ as a natural, protective agent against neuro-toxicity induced by manganese chloride during the gestation and lactation periods.

The effects of the administration of two different doses of manganese on short-term spatial memory and anxiety-like behavior in rats

Directory of Open Access Journals (Sweden)

Hogas M.

2011-01-01

Full Text Available Manganese is a very well known neurotoxic agent. It has been mainly linked to impaired motor skills and disturbed psychomotor development. However, very few aspects are known about the cognitive deficits and behavioral consequences of chronic manganese exposure. In this context, we report herein our findings regarding short-term spatial memory, motor and anxiety-like behavior assessments in male Wistar rats exposed for 45 days to two different doses (3 mg/kg b.w., i.p. and 10 mg/kg b.w., i.p. of manganese. Behavior testing (Y-maze task and elevated plus maze was performed after 45 days of manganese administration. Chronic manganese exposure in Wistar rats led to behavioral alterations consisting of cognitive deficiencies in the Y-maze task and anxiety/compulsive-like behaviors in the elevated plus maze, but no motor disturbances as tested by the number of arm entries in the Y-maze. Additional work is necessary to understand the longterm effects of different doses and dosing regimens of manganese on cognitive/affective and motor functioning.

Phase transformations in Higher Manganese Silicides

Energy Technology Data Exchange (ETDEWEB)

Allam, A. [MADIREL, UMR 7246 CNRS - Universite Aix-Marseille, av Normandie-Niemen, 13397 Marseille Cedex 20 (France); IM2NP, UMR 7334 CNRS - Universite Aix-Marseille, av Normandie-Niemen, Case 142, 13397 Marseille Cedex 20 (France); Boulet, P. [MADIREL, UMR 7246 CNRS - Universite Aix-Marseille, av Normandie-Niemen, 13397 Marseille Cedex 20 (France); Nunes, C.A. [Departamento de Engenharia de Materiais (DEMAR), Escola de Engenharia de Lorena (EEL), Universidade de Sao Paulo - USP, Caixa Postal 116, 12600-970 Lorena, Sao Paulo (Brazil); Sopousek, J.; Broz, P. [Masaryk University, Faculty of Science, Department of Chemistry, Kolarska 2, 611 37 Brno (Czech Republic); Masaryk University, Central European Institute of Technology, CEITEC, Kamenice 753/5, 625 00 Brno (Czech Republic); Record, M.-C., E-mail: m-c.record@univ-cezanne.fr [IM2NP, UMR 7334 CNRS - Universite Aix-Marseille, av Normandie-Niemen, Case 142, 13397 Marseille Cedex 20 (France)

2013-02-25

Highlights: Black-Right-Pointing-Pointer The phase transitions of the Higher Manganese Silicides were investigated. Black-Right-Pointing-Pointer The samples were characterised by XRD, DTA and DSC. Black-Right-Pointing-Pointer Mn{sub 27}Si{sub 47} is the stable phase at room temperature and under atmospheric pressure. Black-Right-Pointing-Pointer At around 800 Degree-Sign C, Mn{sub 27}Si{sub 47} is transformed into Mn{sub 15}Si{sub 26}. Black-Right-Pointing-Pointer The phase transition is of a second order. - Abstract: This work is an investigation of the phase transformations of the Higher Manganese Silicides in the temperature range [100-1200 Degree-Sign C]. Several complementary experimental techniques were used, namely in situ X-ray Diffraction (XRD), Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). The evolution of both the lattice parameters and the thermal expansion coefficients was determined from in situ XRD measurements. The stability of the samples was investigated by thermal analysis (DTA) and Cp measurements (DSC). This study shows that Mn{sub 27}Si{sub 47} which is the stable phase at room temperature and under atmospheric pressure undergoes a phase transformation at around 800 Degree-Sign C. Mn{sub 27}Si{sub 47} is transformed into Mn{sub 15}Si{sub 26}. This phase transformation seems to be of a second order one. Indeed it was not evidenced by DTA and by contrast it appears on the Cp curve.

Manganese concentration in human saliva using NAA

Energy Technology Data Exchange (ETDEWEB)

Lewgoy, Hugo R., E-mail: hugorl@usp.br [Universidade Bandeirante Anhanguera (UNIBAN), Sao Paulo, SP (Brazil); Zamboni, Cibele B.; Medeiros, Ilca M.M.A.; Medeiros, Jose A.G. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

In this investigation the Manganese levels in human whole saliva were determined using Neutron Activation Analysis (NAA) technique for the proposition of an indicative interval. The measurements were performed considering gender and lifestyle factors of Brazilian inhabitants (non-smokers, non-drinkers and no history of toxicological exposure). The results emphasize that the indicative interval is statistically different by gender. These data are useful for identifying or preventing some diseases in the Brazilian population. (author)

Manganese concentration in human saliva using NAA

International Nuclear Information System (INIS)

Lewgoy, Hugo R.; Zamboni, Cibele B.; Medeiros, Ilca M.M.A.; Medeiros, Jose A.G. de

2013-01-01

In this investigation the Manganese levels in human whole saliva were determined using Neutron Activation Analysis (NAA) technique for the proposition of an indicative interval. The measurements were performed considering gender and lifestyle factors of Brazilian inhabitants (non-smokers, non-drinkers and no history of toxicological exposure). The results emphasize that the indicative interval is statistically different by gender. These data are useful for identifying or preventing some diseases in the Brazilian population. (author)

The Effect of Remelting on the Physical Properties of Borotellurite Glass Doped with Manganese

Science.gov (United States)

Hashim, Syed Putra Hashim Syed; Sidek, Haji Abdul Aziz; Halimah, Mohamed Kamari; Matori, Khamirul Amin; Yusof, Wan Mohamad Daud Wan; Zaid, Mohd Hafiz Mohd

2013-01-01

A systematic set of borotellurite glasses doped with manganese (1–x) [(B2O3)0.3(TeO2)0.7]-xMnO, with x = 0.1, 0.2, 0.3 and 0.4 mol%, were successfully synthesized by using a conventional melt and quench-casting technique. In this study, the remelting effect of the glass samples on their microstructure was investigated through density measurement and FT-IR spectra and evaluated by XRD techniques. Initial experimental results from XRD evaluation show that there are two distinct phases of glassy and crystallite microstructure due to the existence of peaks in the sample. The different physical behaviors of the studied glasses were closely related to the concentration of manganese in each phase. FTIR spectra revealed that the addition of manganese oxide contributes the transformation of TeO4 trigonal bipyramids with bridging oxygen (BO) to TeO3 trigonal pyramids with non-bridging oxygen (NBO). PMID:23296276

The Effect of Remelting on the Physical Properties of Borotellurite Glass Doped with Manganese

Directory of Open Access Journals (Sweden)

Syed Putra Hashim Syed Hashim

2013-01-01

Full Text Available A systematic set of borotellurite glasses doped with manganese (1–x [(B2O30.3(TeO20.7]-xMnO, with x = 0.1, 0.2, 0.3 and 0.4 mol%, were successfully synthesized by using a conventional melt and quench-casting technique. In this study, the remelting effect of the glass samples on their microstructure was investigated through density measurement and FT-IR spectra and evaluated by XRD techniques. Initial experimental results from XRD evaluation show that there are two distinct phases of glassy and crystallite microstructure due to the existence of peaks in the sample. The different physical behaviors of the studied glasses were closely related to the concentration of manganese in each phase. FTIR spectra revealed that the addition of manganese oxide contributes the transformation of TeO4 trigonal bipyramids with bridging oxygen (BO to TeO3 trigonal pyramids with non-bridging oxygen (NBO.

Shape-controlled synthesis and properties of manganese sulfide microcrystals via a biomolecule-assisted hydrothermal process

Energy Technology Data Exchange (ETDEWEB)

Jiang Jinghui; Yu Runnan; Zhu Jianyu; Yi Ran; Qiu Guanzhou [School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083 (China); He Yuehui [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Liu Xiaohe, E-mail: liuxh@mail.csu.edu.cn [School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

2009-06-15

An effective biomolecule-assisted synthetic route has been successfully developed to prepare {gamma}-manganese sulfide (MnS) microtubes under hydrothermal conditions. In the synthetic system, soluble hydrated manganese chloride was employed to supply Mn source and L-cysteine was used as precipitator and complexing reagent. Sea urchin-like {gamma}-MnS and octahedron-like {alpha}-MnS microcrystals could also be selectively obtained by adjusting the process parameters such as hydrothermal temperature and reaction time. The phase structures, morphologies and properties of the as-prepared products were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and photoluminescence spectra (PL). The photoluminescence studies exhibited the correlations between the morphology, size, and shape structure of MnS microcrystals and its optical properties. The formation mechanisms of manganese sulfide microcrystals were discussed based on the experimental results.

Reduction of coupling in fine filamentary Cu-NbTi composites by the addition of manganese to the matrix

International Nuclear Information System (INIS)

Kreilick, T.S.; Gregory, E.; Wong, J.; Scanlan, R.M.; Ghosh, A.K.; Sampson, W.B.; Collings, E.W.

1988-01-01

Proximity coupling has been observed in materials containing 4164 filaments in a pure copper matrix designed and fabricated by Supercon Inc. for SSC dipoles. The effect of manganese additions to the copper matrix in reducing this coupling was assessed in this paper. Two multifilamentary NbTi billets were fabricated for SSC inner cable applications. Each composite contains roughly 11,000 filaments embedded in pure copper and copper manganese matrices. Critical current, magnetization, stability, susceptibility and mechanical analyses of these materials indicated no adverse effects from 0.5 wt.% manganese additions to the copper. Results on coupling reduction are evaluated

In vitro induction of matrix metalloproteinase-2 and matrix metalloproteinase-9 expression in keratinocytes by boron and manganese.

Science.gov (United States)

Chebassier, Nathalie; El Houssein, Ouijja; Viegas, Isabelle; Dréno, Brigitte

2004-08-01

Matrix metalloproteinase (MMP)-2 and MMP-9 are involved in keratinocyte migration and granulation tissue remodeling during wound healing. Thermal water cures are sometimes proposed as complementary treatment for accelerating healing of wounds resulting from burns and/or surgery, but their mechanisms of action remain unknown. Some thermal waters are rich in trace elements such as boron and manganese. Interestingly, clinical studies have shown the beneficial effects of trace elements such as boron and manganese for human wound healing. To try to specify the role of trace elements in cutaneous healing, the present study investigated the effects of these trace elements on the production of MMP-2 and MMP-9 by normal human keratinocytes cultured in vitro. Immunohistochemistry and Western blot showed that intracellular MMP-9 expression in keratinocytes was induced when incubated for 6 h with boron at 10 micro g/ml or manganese at 0.2 micro g/ml. Moreover, gelatin zymography on keratinocyte supernatants showed an increase of gelatinase secretion after 24 h of incubation of keratinocytes with boron or manganese, regardless of concentration. Gelatinase secretion was not associated with keratinocyte proliferation induced by trace elements. Thus, our results suggest that boron and manganese could play a role in the clinical efficiency of thermal water on wound healing.

The detection of magnetotactic bacteria in deep sea sediments from the east Pacific Manganese Nodule Province.

Science.gov (United States)

Dong, Yi; Li, Jinhua; Zhang, Wuchang; Zhang, Wenyan; Zhao, Yuan; Xiao, Tian; Wu, Long-Fei; Pan, Hongmiao

2016-04-01

Magnetotactic bacteria (MTB) are distributed ubiquitously in sediments from coastal environments to the deep sea. The Pacific Manganese Nodule Province contains numerous polymetallic nodules mainly composed of manganese, iron, cobalt, copper and nickel. In the present study we used Illumina MiSeq sequencing technology to assess the communities of putative MTB in deep sea surface sediments at nine stations in the east Pacific Manganese Nodule Province. A total of 402 sequence reads from MTB were classified into six operational taxonomic units (OTUs). Among these, OTU113 and OTU759 were affiliated with the genus Magnetospira, OTU2224 and OTU2794 were affiliated with the genus Magnetococcus and Magnetovibrio, respectively, OTU3017 had no known genus affiliation, and OTU2556 was most similar to Candidatus Magnetananas. Interestingly, OTU759 was widely distributed, occurring at all study sites. Magnetism measurements revealed that all sediments were dominated by low coercivity, non-interacting single domain magnetic minerals. Transmission electron microscopy confirmed that the magnetic minerals were magnetosomes. Our data suggest that diverse putative MTB are widely distributed in deep sea surface sediments from the east Pacific Manganese Nodule Province. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

The effect of Pseudoxanthomonas sp. as manganese oxidizing bacterium on the corrosion behavior of carbon steel

Energy Technology Data Exchange (ETDEWEB)

Ashassi-Sorkhabi, H., E-mail: habib_ashassi@yahoo.com [Electrochemistry Research Laboratory, Physical Chemistry Department, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of); Moradi-Haghighi, M. [Electrochemistry Research Laboratory, Physical Chemistry Department, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of); Zarrini, G. [Microbiology laboratory, Biology Department, Science Faculty, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2012-02-01

The present study investigated the role of manganese oxidizing bacterium (MOB), namely Pseudoxanthomonas sp. on the corrosion behavior of carbon steel. This bacterium was isolated from sewage treatment plants and identified by biochemical and molecular methods. The electrochemical techniques such as open circuit potentiometry, electrochemical impedance spectroscopy, potentiodynamic and cyclic polarization were used to measure the corrosion rate and observe the corrosion mechanism. Also, scanning electron microscopy and X-ray diffraction studies were applied to surface analysis. This study revealed the strong adhesion of the biofilm on the metal surface in the presence of Pseudoxanthomonas sp. that enhanced the corrosion of carbon steel. X-ray diffraction patterns identified a high content of MnO{sub 2} deposition within these biofilms. This is the first report that discloses the involvement of Pseudoxanthomonas sp. as manganese oxidizing bacteria on the corrosion of carbon steel. - Highlights: Black-Right-Pointing-Pointer A new type of manganese oxidizing bacteria, namely Pseudoxanthomonas sp. was indicated. Black-Right-Pointing-Pointer This bacterium can create a biofilm on the part of metal surface and affect localized corrosion. Black-Right-Pointing-Pointer In the presence of biofilm, the diffusion of oxygen vacancies and manganese ions has occurred.

The effect of Pseudoxanthomonas sp. as manganese oxidizing bacterium on the corrosion behavior of carbon steel

International Nuclear Information System (INIS)

Ashassi-Sorkhabi, H.; Moradi-Haghighi, M.; Zarrini, G.

2012-01-01

The present study investigated the role of manganese oxidizing bacterium (MOB), namely Pseudoxanthomonas sp. on the corrosion behavior of carbon steel. This bacterium was isolated from sewage treatment plants and identified by biochemical and molecular methods. The electrochemical techniques such as open circuit potentiometry, electrochemical impedance spectroscopy, potentiodynamic and cyclic polarization were used to measure the corrosion rate and observe the corrosion mechanism. Also, scanning electron microscopy and X-ray diffraction studies were applied to surface analysis. This study revealed the strong adhesion of the biofilm on the metal surface in the presence of Pseudoxanthomonas sp. that enhanced the corrosion of carbon steel. X-ray diffraction patterns identified a high content of MnO 2 deposition within these biofilms. This is the first report that discloses the involvement of Pseudoxanthomonas sp. as manganese oxidizing bacteria on the corrosion of carbon steel. - Highlights: ► A new type of manganese oxidizing bacteria, namely Pseudoxanthomonas sp. was indicated. ► This bacterium can create a biofilm on the part of metal surface and affect localized corrosion. ► In the presence of biofilm, the diffusion of oxygen vacancies and manganese ions has occurred.

Absorption of dietary manganese by dairy cows and the role of plasma proteins and the liver in its homeostasis

International Nuclear Information System (INIS)

Sansom, B.F.; Gibbons, R.A.; Dixon, S.N.; Russell, A.M.; Symonds, H.W.

1976-01-01

The concentration of manganese in the systemic blood plasma of cattle is maintained close to 5 μg/1 whether their diet contains 50 or 1000 ppm manganese. The gut absorbs approximately 1% of this dietary manganese irrespective of its dietary concentration. The homeostasis of plasma manganese concentration must therefore be achieved by an excretory method. In vitro experiments have shown that manganese in plasma became bound to two proteins - to α 2 -macroglobulin, in its divalent Mn 2+ state, and to transferrin, in its trivalent Mn 3+ state. The proportions of 54 Mn bound to these two proteins depended strongly on the temperature of incubation of 54 Mn with plasma, and the temperature and pH at which electrophoresis was subsequently performed. 54 Mn 2+ was bound to transferrin only in the presence of an oxidizing agent such as molecular oxygen, ceruloplasmin or permanganate, and α 2 -macroglobulin was not involved in this process. In vivo experiments using cows with permanently indwelling mesenteric, portal and hepatic venous cannulae have shown that the liver cleared the portal blood quantitatively of free Mn 2+ ions, removed approximately 75% of Mn 2+ bound to α 2 -macroglobulin, but removed practically none of the Mn 3+ transferrin complex. These results suggest that manganese may be absorbed through the gut as Mn 2+ ions; some of these become bound to α 2 -macroblobulin while any excess free ions are extracted by the liver and excreted. Some of those bound to α 2 -macroglobulin enter the systemic circulation and are oxidized, either in the plasma or in tissue, to the Mn 3+ state and become bound to transferring, the form in which manganese is circulated for metabolic purposes. (author)

Uranium in Pacific Deep-Sea Sediments and Manganese Nodules

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Pluger, W. L.; Friedrich, G. H.

1983-01-01

A total of 1344 manganese nodules and 187 pelagic sediments from 9 areas in the North and the South Pacific were analyzed for U by the delayed-neutron counting technique. A strong positive correlation between U and Fe in nodules and sediments suggests a co-precipitative removal from sea water int...

Manganese toxicity with ephedrone abuse manifesting as parkinsonism: a case report

Directory of Open Access Journals (Sweden)

Iqbal Mudassir

2012-02-01

Full Text Available Abstract Introduction Neurologic consequences of manganese toxicity have been recognized since 1837. A new form of presumed manganese poisoning has been reported in drug-addicted persons from Eastern Europe and the Baltic states who have intravenously injected self-prepared methcathinone hydrochloride (ephedrone, which is synthesized from pseudoephedrine hydrochloride using potassium permanganate as a potent oxidant. This clinical syndrome is under-recognized in Western Europe and there are no reported cases in the literature from Ireland. Case presentation We report a 30-year-old Eastern European man who presented with a two-year history of gait disturbance. A neurological assessment revealed features of parkinsonism which included hypophonia, hypomimia, mild bradykinesia and rigidity with no resting tremor. He held his arms slightly abducted from his sides when walking, with a reduction in arm swing. Magnetic resonance imaging of his brain showed a high signal on T1 in the globus pallidus and serum manganese levels were raised. He had no response to levodopa. Conclusion Manganism secondary to ephedrone abuse causing parkinsonism has emerged in Western Europe in recent years due to mass immigration and often remains unrecognized. This paper highlights the various features of this rare cause of parkinsonism and aids in its recognition and subsequent diagnosis. Neurologists in Western Europe will increasingly encounter such patients.

Spectroscopic Characteristics of Highly Selective Manganese Catalysis in Acqueous Polyurethane Systems

Directory of Open Access Journals (Sweden)

Miroljub Barac

2006-11-01

Full Text Available The latest investigations on producing more efficient catalytic aqueouspolyurethane systems are in the domain of metal complexes with mixed ligands. In ourprevious research works, the high selectivity for the isocyanate-hydroxyl reaction inaqueous polyurethane systems has been shown by the manganese(III mixed-ligandcomplexes. The two new complexes have been prepared with two acetylacetonate (acacligands and one maleate ligand and its hydroxylamine derivative of the general formula[Mn(C5H7O22L]. Their structures have been established by using the fundamental analyses,the FTIR and UV/VIS spectroscopic methods, as well as the magnetic measurements. Inorder to explain the different selectivity of the manganese(III mixed-ligand complexes, theUV and ESR spectroscopy have been employed to determine the kinetics of the complexes’decomposition. The thermal stability of the complexes has been determined by way of thedynamic TG method at the heating rate of 5°C⋅min-1 and at the temperature ranged 20-550°C. It suggests the decomposition of the complexes by loss of acid ligand. The main factor in the selective catalysis control in theaqueous polyurethane systems is the nature of the acid ligands and their impact on themanganese(II/manganese(III equilibrium.

Update on a Pharmacokinetic-Centric Alternative Tier II Program for MMT—Part II: Physiologically Based Pharmacokinetic Modeling and Manganese Risk Assessment

Directory of Open Access Journals (Sweden)

Michael D. Taylor

2012-01-01

Full Text Available Recently, a variety of physiologically based pharmacokinetic (PBPK models have been developed for the essential element manganese. This paper reviews the development of PBPK models (e.g., adult, pregnant, lactating, and neonatal rats, nonhuman primates, and adult, pregnant, lactating, and neonatal humans and relevant risk assessment applications. Each PBPK model incorporates critical features including dose-dependent saturable tissue capacities and asymmetrical diffusional flux of manganese into brain and other tissues. Varied influx and efflux diffusion rate and binding constants for different brain regions account for the differential increases in regional brain manganese concentrations observed experimentally. We also present novel PBPK simulations to predict manganese tissue concentrations in fetal, neonatal, pregnant, or aged individuals, as well as individuals with liver disease or chronic manganese inhalation. The results of these simulations could help guide risk assessors in the application of uncertainty factors as they establish exposure guidelines for the general public or workers.

Effects of synthetic parameters on structure and electrochemical performance of spinel lithium manganese oxide by citric acid-assisted sol-gel method

International Nuclear Information System (INIS)

Yi Tingfeng; Dai Changsong; Gao Kun; Hu Xinguo

2006-01-01

The spinel lithium manganese oxide cathode materials were prepared by citric acid-assisted sol-gel method at 623-1073 K in air. The effects of pH value, raw material, synthesis temperature and time on structure and electrochemical performance of spinel lithium manganese oxide are investigated by X-ray diffraction (XRD), scanning electronic microscope (SEM) and cyclic voltammetry (CV). XRD data results strongly suggest that the synthesis temperature is the dominating factors of the formation of spinel phase, and spinel lithium manganese oxide powder with various crystallites size can be obtained by controlling the sintering time. CV shows that spinel lithium manganese oxide powder formed about 973 K presents the best electrochemical performance with well separated two peaks and the highest peak current. Charge-discharge test indicates that spinel lithium manganese oxide powders calcined at higher temperatures have high discharge capacity and capacity loss, and sintered at lower temperatures has low discharge capacity and high capacity retention

Effects of synthetic parameters on structure and electrochemical performance of spinel lithium manganese oxide by citric acid-assisted sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Yi Tingfeng [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: tfyihit@hit.edu.cn; Dai Changsong [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Gao Kun [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Hu Xinguo [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

2006-11-30

The spinel lithium manganese oxide cathode materials were prepared by citric acid-assisted sol-gel method at 623-1073 K in air. The effects of pH value, raw material, synthesis temperature and time on structure and electrochemical performance of spinel lithium manganese oxide are investigated by X-ray diffraction (XRD), scanning electronic microscope (SEM) and cyclic voltammetry (CV). XRD data results strongly suggest that the synthesis temperature is the dominating factors of the formation of spinel phase, and spinel lithium manganese oxide powder with various crystallites size can be obtained by controlling the sintering time. CV shows that spinel lithium manganese oxide powder formed about 973 K presents the best electrochemical performance with well separated two peaks and the highest peak current. Charge-discharge test indicates that spinel lithium manganese oxide powders calcined at higher temperatures have high discharge capacity and capacity loss, and sintered at lower temperatures has low discharge capacity and high capacity retention.

Coulometric microdetermination of organic compounds with manganese(III) and cerium(IV)

International Nuclear Information System (INIS)

Chateau-Gosselin, M.; Patriarche, G.J.

1977-01-01

The oxidation of compounds such as hydroquinon, p-aminophenol, paracetamol and phenacetin was performed using cerium(IV) and manganese(III) coulometrically electrogenerated. Quantitative results obtained are excellent even at the microscale level. (author)

Effect of increased manganese addition and mould type on the ...

Indian Academy of Sciences (India)

Administrator

Effect of increased manganese addition and mould type on the slurry erosion characteristics of .... slurry erosion data in the form of bar diagrams for 5M24 and 10M24 ... being bigger in size with higher austenite retention and the attendant ...

Environmental Exposure to Manganese in Air: Associations with Cognitive Functions

Science.gov (United States)

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...

Structure and Magnetic Properties of a Mixed-Valence Heptanuclear Manganese Cluster.

Science.gov (United States)

Abbati, Gian Luca; Cornia, Andrea; Fabretti, Antonio C.; Caneschi, Andrea; Gatteschi, Dante

1998-07-27

Two novel polynuclear manganese(II,III) complexes have been synthesized by exploiting controlled methanolysis. A one-pot reaction of MnCl(2), NaOMe, dibenzoylmethane (Hdbm), and O(2) in anhydrous methanol, followed by recrystallization from MeOH/CHCl(3) mixtures, afforded the alkoxomanganese complexes [Mn(7)(OMe)(12)(dbm)(6)].CHCl(3).14MeOH (2) and [Mn(2)(OMe)(2)(dbm)(4)] (3). Complex 2 crystallizes in trigonal space group R&thremacr; with a = 14.439(2) Å, alpha = 86.34(1) degrees, and Z = 1. Complex 3 crystallizes in triclinic space group P&onemacr; with a = 9.612(1) Å, b = 10.740(1) Å, c = 13.168(1) Å, alpha = 80.39(1) degrees, beta = 87.66(1) degrees, gamma = 83.57(1) degrees, and Z = 1. The solid-state structure of 2 comprises a [Mn(6)(OMe)(12)(dbm)(6)] "crown" with crystallographically imposed 6-fold symmetry plus a central manganese ion. The layered Mn/O core mimics a fragment of the manganese oxide mineral lithiophorite. Conductivity measurements confirmed the nonionic character of 2 and suggested a mixed-valence Mn(II)(3)Mn(III)(4) formulation. The metrical parameters of the core were analyzed with the aid of bond-valence sum calculations. The central ion is essentially a valence-trapped Mn(II) ion, whereas the average Mn-O distances for the manganese ions of the "crown" are consistent with the presence of two Mn(II) and four Mn(III) ions. However, (1)H NMR spectra in solution strongly support valence localization and suggest that the observed solid-state structure may be a result of static disorder effects. Magnetic susceptibility vs T and magnetization vs field data at low temperature are consistent with an S = (17)/(2) ground state. Complex 3 is a symmetric alkoxo-bridged dimer. The two high-spin Mn(III) ions are antiferromagnetically coupled with J = 0.28(4) cm(-)(1), g = 1.983(2), and D = -2.5(4) cm(-)(1).

Environmental manganese exposure and associations with memory, executive functions, and hyperactivity in Brazilian children.

Science.gov (United States)

Carvalho, Chrissie Ferreira de; Oulhote, Youssef; Martorelli, Marina; Carvalho, Carla Oliveira de; Menezes-Filho, José Antônio; Argollo, Nayara; Abreu, Neander

2018-02-09

Manganese (Mn) is an essential element, however high levels of Mn have been associated with lower neuropsychological performance and behavioral problems in children. We investigated the associations between hair Mn concentrations and neuropsychological and behavioral performances among children with long-term exposure to airborne Mn aged between 7 and 12 years. Neuropsychological performance included tests of: verbal memory, inhibitory control, cognitive flexibility, verbal fluency, and motor function. We used the Conners Abbreviated Rating Scale for teachers to assess students' behaviors of hyperactivity. Hair manganese (MnH) concentrations in children and exposure to airborne manganese from a ferro-manganese alloy plant were analyzed and correlated with tests scores. Multivariable linear models adjusting for potential confounders showed that elevated levels of MnH were associated with lower performance in verbal memory, as measured by the free recall after interference (β = - 1.8; 95% CI: - 3.4, - 0.2), which indicates susceptibility to interference, and Delayed Effect (β = -2.0; 95% CI: -3.7, - 0.2), representing a loss of information over time. Additionally, we found patterns of effect modification by sex in three subtests measuring verbal memory: the free recall after interference score, Interference Effect, and Delayed Effect (all at p < 0.10). Overall, the results suggest that long-term airborne Mn exposure may be associated with lower performance in verbal memory, and hyperactivity behaviors. Copyright © 2018 Elsevier B.V. All rights reserved.

High Rate Performance Nanocomposite Electrode of Mesoporous Manganese Dioxide/Silver Nanowires in KI Electrolytes

Directory of Open Access Journals (Sweden)

Yanhua Jiang

2015-10-01

Full Text Available In recent years, manganese dioxide has become a research hotspot as an electrode material because of its low price. However, it has also become an obstacle to industrialization due to its low ratio of capacitance and the low rate performance which is caused by the poor electrical conductivity. In this study, a KI solution with electrochemical activity was innovatively applied to the electrolyte, and we systematically investigated the rate performance of the mesoporous manganese dioxide and the composite electrode with silver nanowires in supercapacitors. The results showed that when mesoporous manganese dioxide and mesoporous manganese dioxide/silver nanowires composite were used as electrodes, the strength of the current was amplified five times (from 0.1 to 0.5 A/g, the remaining rates of specific capacitance were 95% (from 205.5 down to 197.1 F/g and 92% (from 208.1 down to 191.7 F/g in the KI electrolyte, and the rate performance was much higher than which in an Na2SO4 electrolyte with a remaining rate of 25% (from 200.3 down to 49.1 F/g and 60% (from 187.2 down to 113.1 F/g. The morphology and detail structure were investigated by Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry and Nitrogen adsorption-desorption isotherms. The electrochemical performance was assessed by cyclic voltammograms, galvanostatic charge/discharge and electrochemical impedance spectroscopy.

Manganese removal from mine waters - investigating the occurrence and importance of manganese carbonates

International Nuclear Information System (INIS)

Bamforth, Selina M.; Manning, David A.C.; Singleton, Ian; Younger, Paul L.; Johnson, Karen L.

2006-01-01

Manganese is a common contaminant of mine water and other waste waters. Due to its high solubility over a wide pH range, it is notoriously difficult to remove from contaminated waters. Previous systems that effectively remove Mn from mine waters have involved oxidising the soluble Mn(II) species at an elevated pH using substrates such as limestone and dolomites. However it is currently unclear what effect the substrate type has upon abiotic Mn removal compared to biotic removal by in situ micro-organisms (biofilms). In order to investigate the relationship between substrate type, Mn precipitation and the biofilm community, net-alkaline Mn-contaminated mine water was treated in reactors containing one of the pure materials: dolomite, limestone, magnesite and quartzite. Mine water chemistry and Mn removal rates were monitored over a 3-month period in continuous-flow reactors. For all substrates except quartzite, Mn was removed from the mine water during this period, and Mn minerals precipitated in all cases. In addition, the plastic from which the reactor was made played a role in Mn removal. Manganese oxyhydroxides were formed in all the reactors; however, Mn carbonates (specifically kutnahorite) were only identified in the reactors containing quartzite and on the reactor plastic. Magnesium-rich calcites were identified in the dolomite and magnesite reactors, suggesting that the Mg from the substrate minerals may have inhibited Mn carbonate formation. Biofilm community development and composition on all the substrates was also monitored over the 3-month period using denaturing gradient gel electrophoresis (DGGE). The DGGE profiles in all reactors showed no change with time and no difference between substrate types, suggesting that any microbiological effects are independent of mineral substrate. The identification of Mn carbonates in these systems has important implications for the design of Mn treatment systems in that the provision of a carbonate-rich substrate

Concentrations of heavy metals (lead, manganese, cadmium) in blood and urine of former uranium workers

International Nuclear Information System (INIS)

Apostolova, D.; Pavlova, S.; Paskalev, Z.

1999-01-01

Uranium ores contain heavy metals and other stable chemical elements as oxides, hydro-carbonates, sulphates, etc. During chemical processing of ore they could be transformed into compounds soluble in biologic liquids. The purpose of this study was to determine the combined intoxication of uranium miners and millers by heavy metals and radiation. Heavy metal (lead, manganese and cadmium) concentrations in blood and urine od 149 former uranium miners and millers were determined by AAS method. Data of significantly increased lead and manganese concentration in blood (p<0.05) of two groups were established in comparison with a control group. There is no statistical significant differences in the cadmium concentrations. The lead and manganese blood levels at the uranium millers were significant higher than those of the uranium miner group (p<0.05). Tendency towards increased blood lead concentrations of uranium millers depending on the length of service was established

Concentration of cadmium, zinc and manganese in root, stalk and leaf of spinach and tomato in Hamedan

Directory of Open Access Journals (Sweden)

A. Ghobadi

2016-11-01

Full Text Available Heavy metals are considers as significant environment pollutants. Their entrance into food chain is a serious health hazard to humans. This study was conducted to determine the concentrations of Cadmium, Zinc and Manganese in root, stalk and leaf portions of spinach and tomato. For this reason, during 2014 in Hamedan city, 3 farms with 5 repetitions from each farm were sampled. Samples were subjected to acid-digestion and the concentrations of the elements were assayed by inductively coupled plasma (ICP. According to the results, the average concentrations of heavy metals in root, stalk and leaf of spinach was estimated at: cadmium, 0.14, 0.24, 0.34 mg/kg, zinc, 15.53, 24.82, 35 mg/kg and manganese, 26.59, 24.42, 45.38 mg/kg, respectively. The data for the tomato samples were: cadmium, 16.20, 24.42, 33.81 mg/kg, Zinc, 21.48, 39.74, 52.92 mg/kg and manganese, 26.60, 42.41, 61.90 mg/kg, respectively. The mean concentration of cadmium and manganese in spinach and tomato showed a significant difference with the WHO/FAO standard limit. However, in the case of zinc the difference was insignificant. It was concluded that in this experiment the spinach and tomato samples were polluted with higher concentration of cadmium and manganese than the approved limit of WHO/FAO and therefore was found risky for the consumers.

Loss of hfe function reverses impaired recognition memory caused by olfactory manganese exposure in mice.

Science.gov (United States)

Ye, Qi; Kim, Jonghan

2015-03-01

Excessive manganese (Mn) in the brain promotes a variety of abnormal behaviors, including memory deficits, decreased motor skills and psychotic behavior resembling Parkinson's disease. Hereditary hemochromatosis (HH) is a prevalent genetic iron overload disorder worldwide. Dysfunction in HFE gene is the major cause of HH. Our previous study has demonstrated that olfactory Mn uptake is altered by HFE deficiency, suggesting that loss of HFE function could alter manganese-associated neurotoxicity. To test this hypothesis, Hfe-knockout (Hfe (-/-)) and wild-type (Hfe (+/+)) mice mice were intranasally-instilled with manganese chloride (MnCl2 5 mg/kg) or water daily for 3 weeks and examined for memory function. Olfactory Mn diminished both short-term recognition and spatial memory in Hfe (+/+) mice, as examined by novel object recognition task and Barnes maze test, respectively. Interestingly, Hfe (-/-) mice did not show impaired recognition memory caused by Mn exposure, suggesting a potential protective effect of Hfe deficiency against Mn-induced memory deficits. Since many of the neurotoxic effects of manganese are thought to result from increased oxidative stress, we quantified activities of anti-oxidant enzymes in the prefrontal cortex (PFC). Mn instillation decreased superoxide dismutase 1 (SOD1) activity in Hfe (+/+) mice, but not in Hfe (-/-) mice. In addition, Hfe deficiency up-regulated SOD1 and glutathione peroxidase activities. These results suggest a beneficial role of Hfe deficiency in attenuating Mn-induced oxidative stress in the PFC. Furthermore, Mn exposure reduced nicotinic acetylcholine receptor levels in the PFC, indicating that blunted acetylcholine signaling could contribute to impaired memory associated with intranasal manganese. Together, our model suggests that disrupted cholinergic system in the brain is involved in airborne Mn-induced memory deficits and loss of HFE function could in part prevent memory loss via a potential up-regulation of

Distribution of uranium and thorium isotopes in iron-manganese concretions of the Pacific ocean

International Nuclear Information System (INIS)

Kuznetsov, V.Yu.; Andreev, S.I.

1995-01-01

Distribution of 238 U, 234 U, 232 Th, 230 Th in cross sections of samples from the Pacific Ocean iron-manganese concretions (IMC) of different genetic types has been studied, the results are presented. Possible influence of diagenetic processes in the deposits mentioned on distribution of the radionuclides in iron-manganese septarian nodules has been considered. The assumption is made that remobilization of Mn, Ni, Cu from IMC containing deposits does not upset uranium and thorium distribution in the concretions resulted from sedimentation mechanism of their formation. 18 refs., 3 tabs

Three-dimensional inversion recovery manganese-enhanced MRI of mouse brain using super-resolution reconstruction to visualize nuclei involved in higher brain function.

Science.gov (United States)

Poole, Dana S; Plenge, Esben; Poot, Dirk H J; Lakke, Egbert A J F; Niessen, Wiro J; Meijering, Erik; van der Weerd, Louise

2014-07-01

The visualization of activity in mouse brain using inversion recovery spin echo (IR-SE) manganese-enhanced MRI (MEMRI) provides unique contrast, but suffers from poor resolution in the slice-encoding direction. Super-resolution reconstruction (SRR) is a resolution-enhancing post-processing technique in which multiple low-resolution slice stacks are combined into a single volume of high isotropic resolution using computational methods. In this study, we investigated, first, whether SRR can improve the three-dimensional resolution of IR-SE MEMRI in the slice selection direction, whilst maintaining or improving the contrast-to-noise ratio of the two-dimensional slice stacks. Second, the contrast-to-noise ratio of SRR IR-SE MEMRI was compared with a conventional three-dimensional gradient echo (GE) acquisition. Quantitative experiments were performed on a phantom containing compartments of various manganese concentrations. The results showed that, with comparable scan times, the signal-to-noise ratio of three-dimensional GE acquisition is higher than that of SRR IR-SE MEMRI. However, the contrast-to-noise ratio between different compartments can be superior with SRR IR-SE MEMRI, depending on the chosen inversion time. In vivo experiments were performed in mice receiving manganese using an implanted osmotic pump. The results showed that SRR works well as a resolution-enhancing technique in IR-SE MEMRI experiments. In addition, the SRR image also shows a number of brain structures that are more clearly discernible from the surrounding tissues than in three-dimensional GE acquisition, including a number of nuclei with specific higher brain functions, such as memory, stress, anxiety and reward behavior. Copyright © 2014 John Wiley & Sons, Ltd.

Stability of a novel synthetic amorphous manganese oxide in contrasting soils

Czech Academy of Sciences Publication Activity Database

Ettler, V.; Knytl, V.; Komárek, M.; Della Puppa, L.; Bordas, F.; Mihaljevič, M.; Klementová, Mariana; Šebek, O.

2014-01-01

Roč. 214, FEB (2014), s. 2-9 ISSN 0016-7061 Institutional support: RVO:61388980 Keywords : Amorphous manganese oxide * Stability * Soils * Chemical stabilization * Pollution Subject RIV: CA - Inorganic Chemistry Impact factor: 2.772, year: 2014

Elevated manganese exposure and school-aged children's behavior: a gender-stratified analysis.

Science.gov (United States)

Menezes-Filho, José A; de Carvalho-Vivas, Chrissie F; Viana, Gustavo F S; Ferreira, Junia R D; Nunes, Lorena S; Mergler, Donna; Abreu, Neander

2014-12-01

High levels of waterborne manganese have been associated with problematic behavior in school-aged children, however to date this has not been reported for children exposed to airborne manganese. The objective of the present study was to examine behavioral traits among children with exposure to airborne manganese from a ferro-manganese alloy plant, located in the metropolitan region of Salvador, Brazil. The study included 34 boys and 36 girls, aged 7-12 years, living in two communities within a 3-km radius from the plant. For each child, hair manganese levels (MnH) and blood lead (PbB) levels were analyzed by graphite furnace atomic absorption spectrometry. The Children's Behavior Check List (CBCL) (Portuguese version validated in Brazil) was administered to parents or caregivers, providing scale scores of internalizing (withdrawn, somatic complaints, and anxious/depressed scales), externalizing (disruptive and aggressive) behaviors and a separate scale for attention problems. Median and range for MnH and PbB were 11.48 μg/g (range: 0.52-55.74); 1.1 μg/dL (range: 0.5-6.1), respectively. Spearman correlation analyses showed that several behavioral indices were significantly correlated with MnH levels for girls, but not for boys: total externalizing behavior (rho=0.484 vs rho=0.041) and attention problem scores (rho=0.542 vs rho=0.003) coefficients were significantly at pMnH stratified by sex, adjusting for age and maternal IQ. Total externalizing behaviors and attention problem scores were significantly associated with girls' MnH levels but not with boys'. Adjusting for maternal IQ, the β-coefficients for LogMnH associations with total externalizing and attention problems are 8.85 (95%CI 2.44-15.24) and 4.03 (95%CI 1.50-6.56) for girls. For boys, after adjusting for age, the β-coefficients are 0.08 (95%CI 11.51-11.66) and -0.05 (95%CI 4.34-4.25), respectively. The findings of this study suggest a positive association between elevated Mn exposure and externalizing

Manganese Catalyzed Regioselective C–H Alkylation: Experiment and Computation

KAUST Repository

Wang, Chengming

2018-05-08

A new efficient manganese-catalyzed selective C2-alkylation of indoles via carbenoid insertion has been achieved. The newly developed C-H functionalization protocol provides access to diverse products and shows good functional group tolerance. Mechanistic and computational studies support the formation of a Mn(CO)3 acetate complex as the catalytically active species.

Manganese Catalyzed Regioselective C–H Alkylation: Experiment and Computation

KAUST Repository

Wang, Chengming; Maity, Bholanath; Cavallo, Luigi; Rueping, Magnus

2018-01-01

A new efficient manganese-catalyzed selective C2-alkylation of indoles via carbenoid insertion has been achieved. The newly developed C-H functionalization protocol provides access to diverse products and shows good functional group tolerance. Mechanistic and computational studies support the formation of a Mn(CO)3 acetate complex as the catalytically active species.

Ferromagnetic properties of manganese doped iron silicide

Science.gov (United States)

Ruiz-Reyes, Angel; Fonseca, Luis F.; Sabirianov, Renat

We report the synthesis of high quality Iron silicide (FeSi) nanowires via Chemical Vapor Deposition (CVD). The materials exhibits excellent magnetic response at room temperature, especially when doped with manganese showing values of 2.0 X 10-04 emu for the FexMnySi nanowires. SEM and TEM characterization indicates that the synthesized nanowires have a diameter of approximately 80nm. MFM measurements present a clear description of the magnetic domains when the nanowires are doped with manganese. Electron Diffraction and XRD measurements confirms that the nanowires are single crystal forming a simple cubic structure with space group P213. First-principle calculations were performed on (111) FeSi surface using the Vienna ab initio simulation package (VASP). The exchange correlations were treated under the Ceperley-Alder (CA) local density approximation (LDA). The Brillouin Zone was sampled with 8x8x1 k-point grid. A total magnetic moment of about 10 μB was obtained for three different surface configuration in which the Iron atom nearest to the surface present the higher magnetization. To study the effect of Mn doping, Fe atom was replaced for a Mn. Stronger magnetization is presented when the Mn atom is close to the surface. The exchange coupling constant have been evaluated calculating the energy difference between the ferromagnetic and anti-ferromagnetic configurations.

Heavy metals and manganese oxides in the genesee watershed, New York state: effects of geology and land use

Science.gov (United States)

Whitney, P.R.

1981-01-01

Manganese oxide coatings on gravels from 255 sites on tributary streams in the Genesee River Watershed were analyzed for Mn, Fe, Zn, Cd, Co, Ni, Pb, and Cu. The results were compared with data on bedrock geology, surficial geology and land use, using factor analysis and stepwise multiple regression. All metals except Pb show strong positive correlation with Mn. This association results from the well-known tendency of Mn oxide precipitates to adsorb and incorporate dissolved trace metals. Pb may be present in a separate phase on the gravel surfaces; alternatively Pb abundance may be so strongly influenced by environmental factors that the effect of varying abundance of the carrier phase becomes relatively unimportant. When the effects of varying Mn abundance are allowed for, Pb and to a lesser extent Zn and Cu abundances are seen to be related to commercial, industrial and residential land use. In addition to this pollution effect, all the trace metals, Cd and Ni most strongly, tend to be more abundant in oxide coatings from streams in the forested uplands in the southern part of the area. This probably reflects increased geochemical mobility of the metals in the more acid soils and groundwater of the southern region. A strong Zn anomaly is present in streams draining areas underlain by the Lockport Formation. Oxide coatings in these streams contain up to 5% Zn, originating from disseminated sphalerite in the Lockport and secondary Zn concentrations in the overlying muck soils. The same group of metals, plus calcium and loss on ignition, were determined in the silt and clay (minus 230 mesh) fraction of stream sediments from 129 of the same sites, using a hot nitric acid leach. The amounts of manganese in the sediments are low (average 1020 ppm) and manganese oxides are, at most, of relatively minor significance in the trace-metal geochemistry of these sediments. The bulk of the trace metals in sediment appears to be associated with iron oxides, clays and organic

Equilibrium Structure of Manganese Trifluoride (MnF3) Molecule

International Nuclear Information System (INIS)

Caliskan, M.

2004-01-01

The symmetry lowering in manganese trifluoride molecule due to Jahn-Teller distortion was demonstrated in both the experimental and computational results. The molecule does not have D 3 h (or C 3 v) symmetry, rather it has C 2 v symmetry it has been shown from electron-diffraction measurements, that even a molecule of D 3 h symmetry in its equilibrium geometry would appear as having C 3 v symmetry. The manganese trifluoride molecular structures is an example of concerted applications of electron diffraction experiment and computation. It was found two lower energy structures with C 2 v symmetry, one corresponding to the ground state and another corresponding to the transition state. In this work we have calculate the equilibrium structure of the MnF 3 in the C 2 v configuration using the Interionic Force Model. We have compared our results for equilibrium bond lengths and bond angles with measured values from electron diffraction and with the results of quantum chemical calculations. The agreement can be considered as very reasonable

Reductive Leaching Kinetics of Low Grade Manganese Deposits in H2SO4 Solution Using Malonic Acid as Reducing Agent

OpenAIRE

Taysser Lasheen; S. A. Abu Elenein; W. A. Saleh; A. H Orabi; D. A Ismaiel

2014-01-01

A leaching process was developed to extract manganese and metal values from Alloga manganese concentrate. The preferential leaching process was achieved through reductive leaching in dilute sulfuric acid medium with malonic acid as the reducing agent. Leaching parameters were optimized as 1.0 M H2SO4, 10% malonic acid in solid/liquid ratio 1:10 for 90 min at 80 C and using ore ground to – 74 µm. Under these conditions, the leaching efficiency of manganese reaches 97%, whilst iron dissolution ...

Copper-based electrochemical sensor with palladium electrode for cathodic stripping voltammetry of manganese.

Science.gov (United States)

Kang, Wenjing; Pei, Xing; Bange, Adam; Haynes, Erin N; Heineman, William R; Papautsky, Ian

2014-12-16

In this work, we report on the development of a palladium-based, microfabricated point-of-care electrochemical sensor for the determination of manganese using square wave cathodic stripping voltammetry. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Voltammetry offers an attractive approach to metal detection on the microscale, but traditional carbon, gold, or platinum electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor uses palladium working and auxiliary electrodes and integrates them with a copper-based reference electrode for simple fabrication and compatibility with microfabrication and printed circuit board processing, while maintaining competitive performance in electrochemical detection. Copper electrodes were prepared on glass substrate using a combination of microfabrication procedures followed by electrodeposition of palladium. The disposable sensor system was formed by bonding a poly(dimethylsiloxane) (PDMS) well to the glass substrate. Cathodic stripping voltammetry of manganese using our new disposable palladium-based sensors exhibited 334 nM (18.3 ppb) limit of detection in borate buffer. The sensor was used to demonstrate manganese determination in natural water samples from a pond in Burnet Woods, located in Cincinnati, OH, and the Ohio River.

Effects of manganese oxide and sulphate on the olefin selectivity of iron catalysts in the Fischer Tropsch reaction

NARCIS (Netherlands)

Dijk, van W.L.; Niemantsverdriet, J.W.; Kraan, van der A.M.; van der Baan, Hessel

1982-01-01

Although it has been claimed by various authors that the addition of manganese oxide, MnO, to an iron catalyst gives a marked increase in the olefin selectivity of iron catalysts, we have been unable to confirm these claims in Fischer Tropsch experiments at 513 K for an iron manganese oxide catalyst

Environmental contamination and human exposure to manganese--contribution of methylcyclopentadienyl manganese tricarbonyl in unleaded gasoline.

Science.gov (United States)

Zayed, J; Vyskocil, A; Kennedy, G

1999-01-01

The organomanganese compound MMT (methylcyclopentadienyl manganese tricarbonyl), an antiknock additive in unleaded gasoline, has been used in Canada since 1976. Indeed, Canada is the only country where MMT is almost exclusively used. In October 1995, by court decision the Environmental protection Agency (EPA) granted Ethyl's waiver for the use of MMT in the United States. Paradoxically, in 1997 the federal government of Canada adopted a law (C-29) that banned both the interprovincial trade and the importation for commercial purposes of manganese-based substances, including MMT. However, MMT is currently widely used in Canada because of substantial stockpiling, and six Canadian provinces are challenging the law in the courts. Moreover, MMT has been approved for use in Argentina, Australia, Bulgaria, Russia, and conditionally, in New Zealand. It has been suggested by some scientists that combustion of MMT may be a significant source of exposure to inorganic Mn in urban areas. The crucial question is whether Mn contamination from industrial sources combined with the additional contamination that would result from the widespread use of MMT would lead to toxic effects. Our research efforts have attempted to assess the environmental/ecosystem Mn contamination arising from the combustion of MMT in abiotic and biotic systems as well as human exposure. The experimental evidence acquired so far provides useful information on certain environmental consequences of the use of MMT as well as raising a number of questions. Our results gave evidence indicating that roadside air, soils, plants, and animals may be contaminated by Mn. As well, some specific groups of the population could have a higher level of exposure to Mn. Nevertheless, the levels of exposure remain below international guide values. Further studies and further characterization of dose-response relationships are thus needed to provide successful implementation of evidence-based risk-assessment approaches.

Study on microstructure and mechanical properties of Al–Mg–Si–Cu alloy with high manganese content

International Nuclear Information System (INIS)

Han, Yi; Ma, Ke; Li, Lian; Chen, Wei; Nagaumi, Hiromi

2012-01-01

Highlights: ► We examine the precipitates by HRTEM in the high manganese Al–Mg–Si–Cu alloy. ► Manganese content determines amount of secondary phases after homogenization. ► Increasing magnesium content promotes to precipitate S phase. ► Yield strength of the new alloy is 52–65% higher than that of commercial 6061 alloy. ► Uniform distribution of Mn dispersoids encourages to enhance mechanical properties. -- Abstract: The microstructure and mechanical properties of Al–Mg–Si–Cu alloy with high manganese content were studied in the present work to develop a new alloy. The microstructure features were quantificationally determined by a combination of scanning electron microscope and high resolution transmission electron microscopy. The dominant strengthening precipitates comprising the needle-shaped pre-β″(or β″) and lath-shaped Q′ phases were identified in the T6 temper. With the increase of magnesium content, S phase was promoted to precipitate to give an enhancement in strength. The yield strength of the examined alloys with high manganese content was found to be about 52–65% higher than that of commercial 6061 alloy. It was considered that, in addition to the strengthening precipitates, Mn dispersoids generating the dispersion hardening effect and the homogeneous deformation contributed a lot to the favorable mechanical properties.

Manganese-Catalyzed Aminomethylation of Aromatic Compounds with Methanol as a Sustainable C1 Building Block.

Science.gov (United States)

Mastalir, Matthias; Pittenauer, Ernst; Allmaier, Günter; Kirchner, Karl

2017-07-05

This study represents the first example of a manganese-catalyzed environmentally benign, practical three-component aminomethylation of activated aromatic compounds including naphtols, phenols, pyridines, indoles, carbazoles, and thiophenes in combination with amines and MeOH as a C1 source. These reactions proceed with high atom efficiency via a sequence of dehydrogenation and condensation steps which give rise to selective C-C and C-N bond formations, thereby releasing hydrogen and water. A well-defined hydride Mn(I) PNP pincer complex, recently developed in our laboratory, catalyzes this process in a very efficient way, and a total of 28 different aminomethylated products were synthesized and isolated yields of up to 91%. In a preliminary study, a related Fe(II) PNP pincer complex was shown to catalyze the methylation of 2-naphtol rather than its aminomethylation displaying again the divergent behavior of isoelectronic Mn(I) and Fe(II) PNP pincer systems.

Iron and manganese removal from drinking water

OpenAIRE

Pascu, Daniela-Elena; Neagu (Pascu), Mihaela; Alina Traistaru, Gina; Nechifor, Aurelia Cristina; Raluca Miron, Alexandra

2016-01-01

The purpose of the present study is to find a suitable method for removal of iron and manganese from ground water, considering both local economical and environmental aspects. Ground water is a highly important source of drinking water in Romania. Ground water is naturally pure from bacteria at a 25 m depth or more. However, solved metals may occur and if the levels are too high, the water is not drinkable. Different processes, such as electrochemical and combined electrochemical-adsorption m...

Topotactic oxidative and reductive control of the structures and properties of layered manganese oxychalcogenides.

Science.gov (United States)

Hyett, Geoffrey; Barrier, Nicolas; Clarke, Simon J; Hadermann, Joke

2007-09-12

Topotactic modification, by both oxidation and reduction, of the composition, structures, and magnetic properties of the layered oxychalcogenides Sr4Mn3O7.5Cu2Ch2 (Ch=S, Se) is described. These Mn3+ compounds are composed of alternating perovskite-type strontium manganese oxide slabs separated by anti-fluorite-type copper chalcogenide layers and are intrinsically oxide deficient in the central layer of the perovskite slabs. The systems are unusual examples of perovskite-related compounds that may topotactically be both oxidized by fluorination and reduced by deintercalation of oxygen from the oxide-deficient part of the structure. The compounds exhibit antiferromagnetic ordering of the manganese magnetic moments in the outer layers of the perovskite slabs, while the other moments, in the central layers, exhibit spin-glass-like behavior. Fluorination has the effect of increasing the antiferromagnetic ordering temperature and the size of the ordered moment, whereas reduction destroys magnetic long-range order by introducing chemical disorder which leads to both further disorder and frustration of the magnetic interactions in the manganese oxide slab.

Effects of iron and manganese on the formation of HAAs upon chlorinating Chlorella vulgaris

International Nuclear Information System (INIS)

Ge, Fei; Wu, Xiuzhen; Wang, Na; Zhu, Runliang; Wang, Tong; Xu, Yin

2011-01-01

The major objective of the present study was to investigate the role of iron and manganese on the formation of haloacetic acids (HAAs) when algae are chlorinated at different pHs. The results showed that both iron and manganese can reduce the yields of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) on chlorinating green alga Chlorella vulgaris (C. vulgaris) at a pH range of 6.0-9.0, and the decline of DCAA and TCAA was shown to be more significant at the low pH range. At pH 6.0, DCAA and TCAA yields decreased by 44.5% and 57.3%, respectively with the addition of 0.5 mg L -1 iron, and decreased 39.5% and 49.4%, respectively with the addition of 0.5 mg L -1 manganese. The main reason for decreasing the yields of HAAs as shown by scanning electron microscope (SEM) is that Fe(OH) 3(am) or MnO 2(am) coat the algal cells , which then improves their agglomeration of algal cells which is also revealed by the laser particle size analysis (LPSA).

Photoluminescent properties of nanoporous anodic alumina doped with manganese ions

Energy Technology Data Exchange (ETDEWEB)

Gasenkova, I.V. [State Research and Production Association ' Optic, Optoelectronic and Laser techniques”, 68 Nezavisimosti Ave., Minsk 220072 (Belarus); Mukhurov, N.I., E-mail: n.mukhurov@ifanbel.bas-net.by [State Research and Production Association ' Optic, Optoelectronic and Laser techniques”, 68 Nezavisimosti Ave., Minsk 220072 (Belarus); Zhvavyi, S.P.; Kolesnik, E.E. [State Research and Production Association ' Optic, Optoelectronic and Laser techniques”, 68 Nezavisimosti Ave., Minsk 220072 (Belarus); Stupak, A.P. [B.I.Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 68 Nezavisimosti Ave., Minsk 220072 (Belarus)

2017-05-15

The results are presented of a comparative study of photoluminescent (PL) properties of unalloyed and Mn-alloyed porous anodic alumina (PAA) subjected to annealing at temperatures in the range of ГђВў{sub a}=200–1300 °ГђВЎ. The possibility of alloying of PAA with metal atoms is illustrated through an example of Mn atoms, and the effect of this impurity on the optical properties of aluminum oxide is examined. Alloying of PAA with Mn ions leads to the formation of complex defects including manganese ions and oxygen vacancies. The difference observed in the spectral dependences of the PL intensity of alloyed and unalloyed specimens is explained by the change in the valence of manganese ions in the complex defects. A decrease has been discovered in the PL intensity of the PL bands and R-lines of Mn and Cr ions in the α-phase under prolonged UV-exposure of the alloyed samples.

Mesoporous titanium-manganese dioxide for sulphur mustard and soman decontamination

International Nuclear Information System (INIS)

Stengl, Vaclav; Bludska, Jana; Oplustil, Frantisek; Nemec, Tomas

2011-01-01

Highlights: → New nano-dispersive materials for warfare agents decontamination. → 95% decontamination activities for sulphur mustard. → New materials base on titanium and manganese oxides. -- Abstract: Titanium(IV)-manganese(IV) nano-dispersed oxides were prepared by a homogeneous hydrolysis of potassium permanganate and titanium(IV) oxo-sulphate with 2-chloroacetamide. Synthesised samples were characterised using Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy (SEM). These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (HD or bis(2-chloroethyl)sulphide) and soman (GD or (3,3'-dimethylbutan-2-yl)-methylphosphonofluoridate). Mn 4+ content affects the decontamination activity; with increasing Mn 4+ content the activity increases for sulphur mustard and decreases for soman. The best decontamination activities for sulphur mustard and soman were observed for samples TiMn 3 7 with 18.6 wt.% Mn and TiMn 5 with 2.1 wt.% Mn, respectively.

Treatment of Multi-Tonnage Manganese-Containing Waste Water Using Vermiculite

Directory of Open Access Journals (Sweden)

Vera Anatolevna Matveeva

2018-01-01

Full Text Available The article presents the results of fieldand laboratory studies on the state of surface waters in the impact zone of one of the largest mining enterprises of the Russian Federation, i.e. Kovdor Mining and Processing Combine. On the basis of the data from the monitoring studies, the patterns of migration and transformation of manganese in the system of wastes of enrichment – surface water – are revealed. In order to solve the existing environmental problem, an effective method of treating sewage from manganese using organic sorbent based on vermiculite is proposed. The results of laboratory tests of the sorbent are described depending on the method of its modification, as well as on the composition and properties of the purified water. The proposed method of sewage treatment will reduce the negative impact of the company on surface water, thereby improving the ecological situation in the study area and improving the quality of life of the local population.

Manganese Supplementation in Deer under Balanced Diet Increases Impact Energy and Contents in Minerals of Antler Bone Tissue.

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Jamil Cappelli

Full Text Available Bone ash, collagen, Ca and P composition, are considered the main factors affecting mechanical properties in bones. However, a series of studies in bone and antler have shown that some trace minerals, such as manganese, may play a role whose importance exceeds what may be expected considering their low content. A previous study showed that a reduction in manganese in antlers during a year of late winter frosts led to generalized antler breakage in Spain, which included a reduction of 30% of cortical thickness, 27% reduction in impact energy, and 10% reduction in work to peak force. Starting for this observation, we experimentally studied the effects of manganese supplementation in adults and yearling (yearlings red deer under a balanced diet. Subjects were 29 deer of different age classes (adult n = 19, yearlings n = 10 that were divided in a manganese injected group (n = 14 and a control group (n = 15. Antler content in ashes and minerals, intrinsic mechanical properties and cross section structure were examined at 4 points along the antler beam. A one way ANOVA (mean per antler showed that in yearlings, manganese supplementation only increased its content and that of Fe. However, in adults, Mn supplementation increased the mean content per antler of Ca, Na, P, B, Co, Cu, K, Mn, Ni, Se (while Si content was reduced, and impact work but not Young's modulus of elasticity, bending strength or work to peak force. A GLM series on characteristics in the uppermost part examined in the antler, often showing physiological exhaustion and depletion of body stores, showed also a 16% increase in work to peak force in the antlers of the treated group. Thus, manganese supplementation altered mineral composition of antler and improved structure and some mechanical properties despite animals having a balanced diet.

Manganese Supplementation in Deer under Balanced Diet Increases Impact Energy and Contents in Minerals of Antler Bone Tissue.

Science.gov (United States)

Cappelli, Jamil; Garcia, Andrés; Ceacero, Francisco; Gomez, Santiago; Luna, Salvador; Gallego, Laureano; Gambin, Pablo; Landete-Castillejos, Tomás

2015-01-01

Bone ash, collagen, Ca and P composition, are considered the main factors affecting mechanical properties in bones. However, a series of studies in bone and antler have shown that some trace minerals, such as manganese, may play a role whose importance exceeds what may be expected considering their low content. A previous study showed that a reduction in manganese in antlers during a year of late winter frosts led to generalized antler breakage in Spain, which included a reduction of 30% of cortical thickness, 27% reduction in impact energy, and 10% reduction in work to peak force. Starting for this observation, we experimentally studied the effects of manganese supplementation in adults and yearling (yearlings) red deer under a balanced diet. Subjects were 29 deer of different age classes (adult n = 19, yearlings n = 10) that were divided in a manganese injected group (n = 14) and a control group (n = 15). Antler content in ashes and minerals, intrinsic mechanical properties and cross section structure were examined at 4 points along the antler beam. A one way ANOVA (mean per antler) showed that in yearlings, manganese supplementation only increased its content and that of Fe. However, in adults, Mn supplementation increased the mean content per antler of Ca, Na, P, B, Co, Cu, K, Mn, Ni, Se (while Si content was reduced), and impact work but not Young's modulus of elasticity, bending strength or work to peak force. A GLM series on characteristics in the uppermost part examined in the antler, often showing physiological exhaustion and depletion of body stores, showed also a 16% increase in work to peak force in the antlers of the treated group. Thus, manganese supplementation altered mineral composition of antler and improved structure and some mechanical properties despite animals having a balanced diet.

A multicopper oxidase is essential for manganese oxidation and laccase-like activity in Pedomicrobium sp. ACM 3067.

Science.gov (United States)

Ridge, Justin P; Lin, Marianne; Larsen, Eloise I; Fegan, Mark; McEwan, Alastair G; Sly, Lindsay I

2007-04-01

Pedomicrobium sp. ACM 3067 is a budding-hyphal bacterium belonging to the alpha-Proteobacteria which is able to oxidize soluble Mn2+ to insoluble manganese oxide. A cosmid, from a whole-genome library, containing the putative genes responsible for manganese oxidation was identified and a primer-walking approach yielded 4350 bp of novel sequence. Analysis of this sequence showed the presence of a predicted three-gene operon, moxCBA. The moxA gene product showed homology to multicopper oxidases (MCOs) and contained the characteristic four copper-binding motifs (A, B, C and D) common to MCOs. An insertion mutation of moxA showed that this gene was essential for both manganese oxidation and laccase-like activity. The moxB gene product showed homology to a family of outer membrane proteins which are essential for Type I secretion in Gram-negative bacteria. moxBA has not been observed in other manganese-oxidizing bacteria but homologues were identified in the genomes of several bacteria including Sinorhizobium meliloti 1021 and Agrobacterium tumefaciens C58. These results suggest that moxBA and its homologues constitute a family of genes encoding an MCO and a predicted component of the Type I secretion system.

Manganese in the shelf sediments off the west coast of India

Digital Repository Service at National Institute of Oceanography (India)