Manganese, Metallogenium, and Martian Microfossils

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Stein, L. Y.; Nealson, K. H.

1999-01-01

Manganese could easily be considered an abundant element in the Martian regolith, assuming that the composition of martian meteorites reflects the composition of the planet. Mineralogical analyses of 5 SNC meteorites have revealed an average manganese oxide concentration of 0.48%, relative to the 0.1% concentration of manganese found in the Earth's crust. On the Earth, the accumulation of manganese oxides in oceans, soils, rocks, sedimentary ores, fresh water systems, and hydrothermal vents can be largely attributed to microbial activity. Manganese is also a required trace nutrient for most life forms and participates in many critical enzymatic reactions such as photosynthesis. The wide-spread process of bacterial manganese cycling on Earth suggests that manganese is an important element to both geology and biology. Furthermore, there is evidence that bacteria can be fossilized within manganese ores, implying that manganese beds may be good repositories for preserved biomarkers. A particular genus of bacteria, known historically as Metallogenium, can form star-shaped manganese oxide minerals (called metallogenium) through the action of manganese oxide precipitation along its surface. Fossilized structures that resemble metallogenium have been found in Precambrian sedimentary formations and in Cretaceous-Paleogene cherts. The Cretaceous-Paleogene formations are highly enriched in manganese and have concentrations of trace elements (Fe, Zn, Cu, and Co) similar to modern-day manganese oxide deposits in marine environments. The appearance of metallogenium-like fossils associated with manganese deposits suggests that bacteria may be preserved within the minerals that they form. Additional information is contained in the original extended abstract.

Manganese and acute paranoid psychosis: a case report

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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

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.

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

OpenAIRE

Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

2012-01-01

Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the p...

Actinomycin D synergistically enhances the cytotoxicity of CDDP on KB cells by activating P53 via decreasing P53-MDM2 complex.

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Wang, Lin; Pang, Xiao-Cong; Yu, Zi-Ru; Yang, Sheng-Qian; Liu, Ai-Lin; Wang, Jin-Hua; Du, Guan-Hua

2017-06-01

The aim of this study is to investigate the synergism of low dose of actinomycin D (LDActD) to the cytotoxicity of cisplatin (CDDP) on KB cells. The role of P53 reactivation by LDActD in the synergism and its mechanism were further studied. Cell viability was determined by MTT assay. Apoptosis was determined by AnnexinV-FITC/PI staining. Mitochondrial membrane potential (MMP) was detected by JC-1 staining. Expression of proteins was detected by Western blotting (WB) and/or immunofluorescence (IF). Molecular docking of actinomycin D (ACTD) to Mouse double minute 2 homolog (MDM2) and Mouse double minute 2 homolog X (MDMX). MDMX was analyzed by Discovery Studio. The content of P53-MDM2 complex was detected by ELISA assay. The cytotoxicity of CDDP was increased by the combination of LDActD in kinds of cancer cells. Molecular docking showed strong interaction between ACTD and MDM2/MDMX. Meanwhile, LDActD significantly decreased P53-MDM2 complex. Significant increase of the apoptotic activity by the combination therapy in KB cells is P53 upregulated modulator of apoptosis (PUMA) dependent. In addition to the decrease in MMP, LDActD increased P53 regulated protein and decreased BCL-XL in KB cells. LDActD efficiently enhanced the cytotoxicity of CDDP in cancer cells and induced P53-PUMA-dependent and mitochondria-mediated apoptosis in KB cells. The reactivation of P53 was probably achieved by disturbing the interaction of P53 and MDM2/MDMX.

The sorption of silver by poorly crystallized manganese oxides

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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.

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria.

Science.gov (United States)

Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

2012-11-01

Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10(6) acetate-utilizing manganese-reducing cells cm(-3) in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

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

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

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

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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.

Decreased Cytotoxicity of Peripheral and Peritoneal Natural Killer Cell in Endometriosis.

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Jeung, InCheul; Cheon, Keunyoung; Kim, Mee-Ran

2016-01-01

Endometriosis causes significant chronic pelvic pain, dysmenorrhea, and infertility and affects 10% of all women. In endometriosis, ectopic endometrium surviving after retrograde menstruation exhibits an abnormal immune response characterized by increased levels of activated macrophages and inflammatory cytokines. Particularly, dysfunctional natural killer (NK) cells play an important role in the pathogenesis of the disease by either facilitating or inhibiting the survival, implantation, and proliferation of endometrial cells. NK cells in the peritoneum and peritoneal fluid exhibit reduced levels of cytotoxicity in women with endometriosis. Several cytokines and inhibitory factors in the serum and peritoneal fluid also dysregulate NK cell cytotoxicity. Additionally, increased numbers of immature peripheral NK cells and induction of NK cell apoptosis are evident in the peritoneal fluid of women with endometriosis. The high rate of endometriosis recurrence after pharmaceutical or surgical treatment, which is associated with dysfunctional NK cells, indicates that new immunomodulatory management strategies are required. A good understanding of immune dysfunction would enable improvement of current treatments for endometriosis.

Decreased Cytotoxicity of Peripheral and Peritoneal Natural Killer Cell in Endometriosis

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InCheul Jeung

2016-01-01

Full Text Available Endometriosis causes significant chronic pelvic pain, dysmenorrhea, and infertility and affects 10% of all women. In endometriosis, ectopic endometrium surviving after retrograde menstruation exhibits an abnormal immune response characterized by increased levels of activated macrophages and inflammatory cytokines. Particularly, dysfunctional natural killer (NK cells play an important role in the pathogenesis of the disease by either facilitating or inhibiting the survival, implantation, and proliferation of endometrial cells. NK cells in the peritoneum and peritoneal fluid exhibit reduced levels of cytotoxicity in women with endometriosis. Several cytokines and inhibitory factors in the serum and peritoneal fluid also dysregulate NK cell cytotoxicity. Additionally, increased numbers of immature peripheral NK cells and induction of NK cell apoptosis are evident in the peritoneal fluid of women with endometriosis. The high rate of endometriosis recurrence after pharmaceutical or surgical treatment, which is associated with dysfunctional NK cells, indicates that new immunomodulatory management strategies are required. A good understanding of immune dysfunction would enable improvement of current treatments for endometriosis.

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

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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).

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.

Three-dimensional culture conditions lead to decreased radiation induced cytotoxicity in human mammary epithelial cells

International Nuclear Information System (INIS)

Sowa, Marianne B.; Chrisler, William B.; Zens, Kyra D.; Ashjian, Emily J.; Opresko, Lee K.

2010-01-01

For both targeted and non-targeted exposures, the cellular responses to ionizing radiation have predominantly been measured in two-dimensional monolayer cultures. Although convenient for biochemical analysis, the true interactions in vivo depend upon complex interactions between cells themselves and the surrounding extracellular matrix. This study directly compares the influence of culture conditions on radiation induced cytotoxicity following exposure to low-LET ionizing radiation. Using a three-dimensional (3D) human mammary epithelial tissue model, we have found a protective effect of 3D cell culture on cell survival after irradiation. The initial state of the cells (i.e., 2D versus 3D culture) at the time of irradiation does not alter survival, nor does the presence of extracellular matrix during and after exposure to dose, but long term culture in 3D which offers significant reduction in cytotoxicity at a given dose (e.g. ∼4-fold increased survival at 5 Gy). The cell cycle delay induced following exposure to 2 and 5 Gy was almost identical between 2D and 3D culture conditions and cannot account for the observed differences in radiation responses. However the amount of apoptosis following radiation exposure is significantly decreased in 3D culture relative to the 2D monolayer after the same dose. A likely mechanism of the cytoprotective effect afforded by 3D culture conditions is the down regulation of radiation induced apoptosis in 3D structures.

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

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

Effect of radiotherapy on lymphocyte cytotoxicity in vitro

Energy Technology Data Exchange (ETDEWEB)

Wasserman, J; Melen, B [Central Microbiological Laboratory, Stockholm County Council (Sweden); Blomgren, H; Glas, U; Perlmann, P

1975-11-01

The cytotoxic functions of highly purified blood lymphocytes from patients with breast cancer were studied before and after radiotherapy. Addition of PHA or of rabbit antibodies to target cells (chicken erythrocytes) were chosen as two means of inducing lymphocyte cytotoxicity in vitro. The proportion of T and non-T lymphocytes was determined by means of E and EAC rosette tests. The antibody-induced cytotoxicity of lymphocytes decreased following radiotherapy while that mediated by PHA remained unchanged. There was some reduction in the percentage of EAC rosette-forming cells. These results, as well as earlier observations, suggest that the decrease in the peripheral blood of the proportion of lymphocytes with receptors for activated complement is responsible for changes in the antibody-mediated lymphocyte cytotoxicity.

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

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

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).

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.

The suppression of manganese superoxide dismutase decreased the survival of human glioblastoma multiforme T98G cells

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Novi S. Hardiany

2017-05-01

Full Text Available Background: Glioblastoma multiforme (GBM is a primary malignant brain tumor which has poor prognosis. High incidence of oxidative stress-based therapy resistance could be related to the high antioxidant status of GBM cells. Our previous study has reported that manganese superoxide dismutase (MnSOD antioxidant expression was significantly higher in high grade glioma than in low grade. The aim of this study was to analyze the impact of MnSOD suppression toward GBM cell survival.Methods: This study is an experimental study using human glioblastoma multiforme T98G cell line. Suppression of MnSOD expression was performed using in vitro transfection MnSOD-siRNA. The MnSOD expression was analyzed by measuring the mRNA using real time RT-PCR, protein using ELISA technique, and specific activity of enzyme using inhibition of xantine oxidase. Concentration of reactive oxygen species (ROS intracellular was determined by measuring superoxide radical and hydrogen peroxide. Cell survival was analyzed by measuring viability, proliferation, and cell apoptosis.Results: In vitro transfection of MnSOD-siRNA suppressed the mRNA, protein, and specific activity of MnSOD. This treatment significantly increased the concentration of superoxide radical; however, it did not influence the concentration of hydrogen peroxide. Moreover, viability MnSOD-suppressing cell significantly decreased, accompanied by increase of cell apoptosis without affecting cell proliferation.Conclusion: The suppression of MnSOD expression leads to decrease glioblastoma multiforme cell survival, which was associated to the increase of cell apoptotic.

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.

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

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.

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)

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.

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.

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.

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.

Iron(III) and manganese(II) substituted hydroxyapatite nanoparticles: Characterization and cytotoxicity analysis

International Nuclear Information System (INIS)

Li Yan; Nam, C T; Ooi, C P

2009-01-01

Calcium hydroxyapatite (HA) is the main inorganic component of natural bones and can bond to bone directly in vivo. Thus HA is widely used as coating material on bone implants due to its good osteoconductivity and osteoinductivity. Metal ions doped HA have been used as catalyst or absorbents since the ion exchange method has introduced new properties in HA which are inherent to the metal ions. For example, Mn 2+ ions have the potential to increase cell adhesion while Fe 3+ ions have magnetic properties. Here, Fe(III) substituted hydroxyapatite (Fe-HA) and Mn(II) substituted hydroxyapatite (Mn-HA) were produced by wet chemical method coupled with ion exchange mechanism. Compared with pure HA, the colour of both Fe-HA and Mn-HA nanoparticles changed from white to brown and pink respectively. The intensity of the colours increased with increasing substitution concentrations. XRD patterns showed that all samples were single phased HA while the FTIR spectra revealed all samples possessed the characteristic phosphate and hydroxyl adsorption bands of HA. However, undesired adsorption bands of carbonate substitution (B-type carbonated HA) and H 2 O were also detected, which was reasonable since the wet chemical method was used in the synthesis of these nanoparticles. FESEM images showed all samples were elongated spheroids with small size distribution and of around 70 nm, regardless of metal ion substitution concentrations. EDX spectra showed the presence of Fe and Mn and ICP-AES results revealed all metal ion substituted HA were non-stoichiometric (Ca/P atomic ratio deviates from 1.67). Fe-HA nanoparticles were paramagnetic and the magnetic susceptibility increased with the increase of Fe content. Based on the extraction assay for cytotoxicity test, both Fe-HA and Mn-HA displayed non-cytotoxicity to osteoblast.

Protective Effects of Curcumin on Manganese-Induced BV-2 Microglial Cell Death.

Science.gov (United States)

Park, Euteum; Chun, Hong Sung

2017-08-01

Curcumin, a bioactive component in tumeric, has been shown to exert antioxidant, anti-inflammatory, anticarcinogenic, hepatoprotective, and neuroprotective effects, but the effects of curcumin against manganese (Mn)-mediated neurotoxicity have not been studied. This study examined the protective effects of curcumin on Mn-induced cytotoxicity in BV-2 microglial cells. Curcumin (0.1-10 µM) dose-dependently prevented Mn (250 µM)-induced cell death. Mn-induced mitochondria-related apoptotic characteristics, such as caspase-3 and -9 activation, cytochrome c release, Bax increase, and Bcl-2 decrease, were significantly suppressed by curcumin. In addition, curcumin significantly increased intracellular glutathione (GSH) and moderately potentiated superoxide dismutase (SOD), both which were diminished by Mn treatment. Curcumin pretreatment effectively suppressed Mn-induced upregulation of malondialdehyde (MDA), total reactive oxygen species (ROS). Moreover, curcumin markedly inhibited the Mn-induced mitochondrial membrane potential (MMP) loss. Furthermore, curcumin was able to induce heme oxygenase (HO)-1 expression. Curcumin-mediated inhibition of ROS, down-regulation of caspases, restoration of MMP, and recovery of cell viability were partially reversed by HO-1 inhibitor (SnPP). These results suggest the first evidence that curcumin can prevent Mn-induced microglial cell death through the induction of HO-1 and regulation of oxidative stress, mitochondrial dysfunction, and apoptotic events.

Effects of iron and manganese on the formation of HAAs upon chlorinating Chlorella vulgaris

Energy Technology Data Exchange (ETDEWEB)

Ge, Fei, E-mail: gefei@xtu.edu.cn [Department of Environmental Science and Engineering, Xiangtan University, Egongtang Road, Xiangtan, Hunan 411105 (China); Wu, Xiuzhen; Wang, Na; Zhu, Runliang; Wang, Tong; Xu, Yin [Department of Environmental Science and Engineering, Xiangtan University, Egongtang Road, Xiangtan, Hunan 411105 (China)

2011-05-15

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{sup -1} iron, and decreased 39.5% and 49.4%, respectively with the addition of 0.5 mg L{sup -1} manganese. The main reason for decreasing the yields of HAAs as shown by scanning electron microscope (SEM) is that Fe(OH){sub 3(am)} or MnO{sub 2(am)} coat the algal cells{sub ,} which then improves their agglomeration of algal cells which is also revealed by the laser particle size analysis (LPSA).

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)

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...

Preclinical evaluation of severely defective manganese-based nanocrystal as a liver-specific contrast media for MR imaging: comparison with Gd-EOB-DTPA and MnDPDP

Science.gov (United States)

Zhang, Yu; Xiao, Xiao-ping; Shu, Ting; Cai, Jing; Xiao, Xin-lan; Li, Yan-shu; Zhang, Zhong-wei; Tang, Qun

2018-06-01

Manganese-based (chemically formulated of KMnF3) nanocrystal was evaluated as a liver-specific contrast agent for MR imaging and its imaging performance was also compared with those of two commercial hepatobiliary contrast media (Gd-EOB-DTPA and MnDPDP). KMnF3 nanocrystal was post-treated using a plasma technique to cause severe defects, leading to appropriate water dispersibility and high relaxivity. Severely defective KMnF3 nanocrystal (SD-KMnF3) has characteristic high tolerance, as evidenced by cytotoxicity on the macrophage cell, and acute and subchronic toxicity on the healthy mouse. SD-KMnF3 showed better hepatic MR imaging as the T 1 relaxation time of the liver decreased to only 17% of the control group, compared to 22% of the control group for Gd-EOB-DTPA (P hepatocarcinoma or metastatic lesions.

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

SIRT1 overexpression decreases cisplatin-induced acetylation of NF-κB p65 subunit and cytotoxicity in renal proximal tubule cells

International Nuclear Information System (INIS)

Jung, Yu Jin; Lee, Jung Eun; Lee, Ae Sin; Kang, Kyung Pyo; Lee, Sik; Park, Sung Kwang; Lee, Sang Yong; Han, Myung Kwan; Kim, Duk Hoon; Kim, Won

2012-01-01

Highlights: ► Cisplatin increases acetylation of NF-κB p65 subunit in HK2 cells. ► SIRT1 overexpression decreases cisplatin-induced p65 acetylation and -cytotoxicity. ► Resveratrol decreased cisplatin-induced cell viability through deacetylation of p65. -- Abstract: As the increased acetylation of p65 is linked to nuclear factor-κB (NF-κB) activation, the regulation of p65 acetylation can be a potential target for the treatment of inflammatory injury. Cisplatin-induced nephrotoxicity is an important issue in chemotherapy of cancer patients. SIRT1, nicotinamide adenine dinucleotide (NAD + )-dependent protein deacetylase, has been implicated in a variety of cellular processes such as inflammatory injury and the control of multidrug resistance in cancer. However, there is no report on the effect of SIRT1 overexpression on cisplatin-induced acetylation of p65 subunit of NF-κB and cell injury. To investigate the effect of SIRT1 in on cisplatin-induced acetylation of p65 subunit of NF-κB and cell injury, HK2 cells were exposed with SIRT1 overexpression, LacZ adenovirus or dominant negative adenovirus after treatment with cisplatin. While protein expression of SIRT1 was decreased by cisplatin treatment compared with control buffer treatment, acetylation of NF-κB p65 subunit was significantly increased after treatment with cisplatin. Overexpression of SIRT1 ameliorated the increased acetylation of p65 of NF-κB during cisplatin treatment and cisplatin-induced cytotoxicity. Further, treatment of cisplatin-treated HK2 cells with resveratrol, a SIRT1 activator, also decreased acetylation of NF-κB p65 subunit and cisplatin-induced increase of the cell viability in HK2 cells. Our findings suggests that the regulation of acetylation of p65 of NF-κB through SIRT1 can be a possible target to attenuate cisplatin-induced renal cell damage.

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...

Association of arsenic, cadmium and manganese exposure with neurodevelopment and behavioural disorders in children: A systematic review and meta-analysis

International Nuclear Information System (INIS)

Rodríguez-Barranco, Miguel; Lacasaña, Marina; Aguilar-Garduño, Clemente; Alguacil, Juan; Gil, Fernando; González-Alzaga, Beatriz; Rojas-García, Antonio

2013-01-01

The aim of this study was to analyse the scientific evidence published to date on the potential effects on neurodevelopment and behavioural disorders in children exposed to arsenic, cadmium and manganese and to quantify the magnitude of the effect on neurodevelopment by pooling the results of the different studies. We conducted a systematic review of original articles from January 2000 until March 2012, that evaluate the effects on neurodevelopment and behavioural disorders due to pre or post natal exposure to arsenic, cadmium and manganese in children up to 16 years of age. We also conducted a meta-analysis assessing the effects of exposure to arsenic and manganese on neurodevelopment. Forty-one articles that evaluated the effects of metallic elements on neurodevelopment and behavioural disorders met the inclusion criteria: 18 examined arsenic, 6 cadmium and 17 manganese. Most studies evaluating exposure to arsenic (13 of 18) and manganese (14 of 17) reported a significant negative effect on neurodevelopment and behavioural disorders. Only two studies that evaluated exposure to cadmium found an association with neurodevelopmental or behavioural disorders. The results of our meta-analysis suggest that a 50% increase of arsenic levels in urine would be associated with a 0.4 decrease in the intelligence quotient (IQ) of children aged 5–15 years. Moreover a 50% increase of manganese levels in hair would be associated with a decrease of 0.7 points in the IQ of children aged 6–13 years. There is evidence that relates arsenic and manganese exposure with neurodevelopmental problems in children, but there is little information on cadmium exposure. Few studies have evaluated behavioural disorders due to exposure to these compounds, and manganese is the only one for which there is more evidence of the existence of association with attention deficit disorder with hyperactivity. - Highlights: • We evaluated the association between As, Cd and Mn with neurodevelopment in

Association of arsenic, cadmium and manganese exposure with neurodevelopment and behavioural disorders in children: A systematic review and meta-analysis

Energy Technology Data Exchange (ETDEWEB)

Rodríguez-Barranco, Miguel [Andalusian School of Public Health (EASP), Granada (Spain); Lacasaña, Marina, E-mail: marina.lacasana.easp@juntadeandalucia.es [Andalusian School of Public Health (EASP), Granada (Spain); CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain); Aguilar-Garduño, Clemente [CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain); Centre Superior d' Investigació en Salut Pública, Conselleria de Sanitat, Valencia (Spain); Alguacil, Juan [CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain); Department of Environmental Biology and Public Health, University of Huelva, Huelva (Spain); Gil, Fernando [Department of Legal Medicine and Toxicology, University of Granada, Granada (Spain); González-Alzaga, Beatriz [Andalusian School of Public Health (EASP), Granada (Spain); Rojas-García, Antonio [CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain)

2013-06-01

The aim of this study was to analyse the scientific evidence published to date on the potential effects on neurodevelopment and behavioural disorders in children exposed to arsenic, cadmium and manganese and to quantify the magnitude of the effect on neurodevelopment by pooling the results of the different studies. We conducted a systematic review of original articles from January 2000 until March 2012, that evaluate the effects on neurodevelopment and behavioural disorders due to pre or post natal exposure to arsenic, cadmium and manganese in children up to 16 years of age. We also conducted a meta-analysis assessing the effects of exposure to arsenic and manganese on neurodevelopment. Forty-one articles that evaluated the effects of metallic elements on neurodevelopment and behavioural disorders met the inclusion criteria: 18 examined arsenic, 6 cadmium and 17 manganese. Most studies evaluating exposure to arsenic (13 of 18) and manganese (14 of 17) reported a significant negative effect on neurodevelopment and behavioural disorders. Only two studies that evaluated exposure to cadmium found an association with neurodevelopmental or behavioural disorders. The results of our meta-analysis suggest that a 50% increase of arsenic levels in urine would be associated with a 0.4 decrease in the intelligence quotient (IQ) of children aged 5–15 years. Moreover a 50% increase of manganese levels in hair would be associated with a decrease of 0.7 points in the IQ of children aged 6–13 years. There is evidence that relates arsenic and manganese exposure with neurodevelopmental problems in children, but there is little information on cadmium exposure. Few studies have evaluated behavioural disorders due to exposure to these compounds, and manganese is the only one for which there is more evidence of the existence of association with attention deficit disorder with hyperactivity. - Highlights: • We evaluated the association between As, Cd and Mn with neurodevelopment in

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

In vitro study of manganese-doped bioactive glasses for bone regeneration.

Science.gov (United States)

Miola, Marta; Brovarone, Chiara Vitale; Maina, Giovanni; Rossi, Federica; Bergandi, Loredana; Ghigo, Dario; Saracino, Silvia; Maggiora, Marina; Canuto, Rosa Angela; Muzio, Giuliana; Vernè, Enrica

2014-05-01

A glass belonging to the system SiO2-P2O5-CaO-MgO-Na2O-K2O was modified by introducing two different amounts of manganese oxide (MnO). Mn-doped glasses were prepared by melt and quenching technique and characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) observation and energy dispersion spectrometry (EDS) analysis. In vitro bioactivity test in simulated body fluid (SBF) showed a slight decrease in the reactivity kinetics of Mn-doped glasses compared to the glass used as control; however the glasses maintained a good degree of bioactivity. Mn-leaching test in SBF and minimum essential medium (MEM) revealed fluctuating trends probably due to a re-precipitation of Mn compounds during the bioactivity process. Cellular tests showed that all the Mn-doped glasses, up to a concentration of 50 μg/cm(2) (μg of glass powders/cm(2) of cell monolayer), did not produce cytotoxic effects on human MG-63 osteoblasts cultured for up to 5 days. Finally, biocompatibility tests demonstrated a good osteoblast proliferation and spreading on Mn-doped glasses and most of all that the Mn-doping can promote the expression of alkaline phosphatase (ALP) and some bone morphogenetic proteins (BMPs). Copyright © 2014 Elsevier B.V. All rights reserved.

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...

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.

Water-soluble Manganese and Iron Mesotetrakis(carboxyl)porphyrin: DNA Binding, Oxidative Cleavage, and Cytotoxic Activities.

Science.gov (United States)

Shi, Lei; Jiang, Yi-Yu; Jiang, Tao; Yin, Wei; Yang, Jian-Ping; Cao, Man-Li; Fang, Yu-Qi; Liu, Hai-Yang

2017-06-29

Two new water-soluble metal carboxyl porphyrins, manganese (III) meso -tetrakis (carboxyl) porphyrin and iron (III) meso -tetrakis (carboxyl) porphyrin, were synthesized and characterized. Their interactions with ct-DNA were investigated by UV-Vis titration, fluorescence spectra, viscosity measurement and CD spectra. The results showed they can strongly bind to ct-DNA via outside binding mode. Electrophoresis experiments revealed that both complexes can cleave pBR322 DNA efficiently in the presence of hydrogen peroxide, albeit 2-Mn exhibited a little higher efficiency. The inhibitor tests suggest the oxidative DNA cleavage by these two complexes may involve hydroxyl radical active intermediates. Notably, 2-Mn exhibited considerable photocytotoxicity against Hep G2 cell via triggering a significant generation of ROS and causing disruption of MMP after irradiation.

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).

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

Directory of Open Access Journals (Sweden)

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.

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.

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.

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)

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

Influence of non-metallic inclusions on fatigue strength of high manganese steel

International Nuclear Information System (INIS)

Maekawa, I.; Shibata, H.; Lee, J.H.; Nishida, Shin-ichi

1991-01-01

Six series of high manganese austenitic steel, which contain different inclusion quantity, were prepared. Fatigue experiments, tensile tests and Charpy tests were carried out. Influence of non-metallic inclusion and of temperature on the stress intensity threshold, fatigue crack propagation behavior, elastic-plastic fracture toughness and Charpy value were studied at room temperature and low temperature. In general, strength of this high manganese steel was reduced with increase of inclusion content. Influences of the direction of elongated inclusion with regard to the rolling direction on their strengths were also discussed based on SEM observation and numerical analysis for the stress concentration at a crack tip when an inclusion was near by the tip. According to these results, an inclusion acted as an obstacle to crack propagation for LT specimen. The roughness of fracture surface of ST specimen was larger than that of SL specimen, and the crack growth rate of the former was less than that of the latter. Fatigue life was increased with decrease of temperature, and mechanical parameters such as ΔK th and J 1c were decreased with increase of temperature. The Charpy value decreased clearly with decrease of temperature

SIRT1 overexpression decreases cisplatin-induced acetylation of NF-{kappa}B p65 subunit and cytotoxicity in renal proximal tubule cells

Energy Technology Data Exchange (ETDEWEB)

Jung, Yu Jin; Lee, Jung Eun; Lee, Ae Sin [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Kang, Kyung Pyo; Lee, Sik; Park, Sung Kwang [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Sang Yong [Department of Diagnostic Radiology, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Han, Myung Kwan [Department of Microbiology, Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Kim, Duk Hoon [Division of Forensic Medicine, National Forensic Service, Seoul (Korea, Republic of); Kim, Won, E-mail: kwon@jbnu.ac.kr [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju (Korea, Republic of)

2012-03-09

Highlights: Black-Right-Pointing-Pointer Cisplatin increases acetylation of NF-{kappa}B p65 subunit in HK2 cells. Black-Right-Pointing-Pointer SIRT1 overexpression decreases cisplatin-induced p65 acetylation and -cytotoxicity. Black-Right-Pointing-Pointer Resveratrol decreased cisplatin-induced cell viability through deacetylation of p65. -- Abstract: As the increased acetylation of p65 is linked to nuclear factor-{kappa}B (NF-{kappa}B) activation, the regulation of p65 acetylation can be a potential target for the treatment of inflammatory injury. Cisplatin-induced nephrotoxicity is an important issue in chemotherapy of cancer patients. SIRT1, nicotinamide adenine dinucleotide (NAD{sup +})-dependent protein deacetylase, has been implicated in a variety of cellular processes such as inflammatory injury and the control of multidrug resistance in cancer. However, there is no report on the effect of SIRT1 overexpression on cisplatin-induced acetylation of p65 subunit of NF-{kappa}B and cell injury. To investigate the effect of SIRT1 in on cisplatin-induced acetylation of p65 subunit of NF-{kappa}B and cell injury, HK2 cells were exposed with SIRT1 overexpression, LacZ adenovirus or dominant negative adenovirus after treatment with cisplatin. While protein expression of SIRT1 was decreased by cisplatin treatment compared with control buffer treatment, acetylation of NF-{kappa}B p65 subunit was significantly increased after treatment with cisplatin. Overexpression of SIRT1 ameliorated the increased acetylation of p65 of NF-{kappa}B during cisplatin treatment and cisplatin-induced cytotoxicity. Further, treatment of cisplatin-treated HK2 cells with resveratrol, a SIRT1 activator, also decreased acetylation of NF-{kappa}B p65 subunit and cisplatin-induced increase of the cell viability in HK2 cells. Our findings suggests that the regulation of acetylation of p65 of NF-{kappa}B through SIRT1 can be a possible target to attenuate cisplatin-induced renal cell damage.

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

Chromatogram Profiles and Cytotoxic Activity of Irradiated Mahkota Dewa (Phaleria Macrocarpa (Scheff.) Boerl) Leaves

International Nuclear Information System (INIS)

Katrin, E.; Winarno, H.; Selvie

2011-01-01

Gamma irradiation has been used by the industries for preservation of herbal medicine, but it has not been studied the effect of gamma irradiation on their efficacy, especially their bioactivity as anticancer substances. The purpose of this research was to study the effect of gamma irradiation on the mahkota dewa leaves which has been claimed to contain potent anticancer substances. Maceration of dried mahkota dewa leaves successively with n-hexane, ethyl acetate, and ethanol gave crude extracts which the ethyl acetate was the most cytotoxic extract against leukemia L1210 cells with an inhibition concentration fifty (IC 50 ) value of 10.3 μg/ml. Further separation of ethyl acetate extract by column chromatograph gave 7 fractions, and fraction 2 showed the most cytotoxic fraction exhibited the most cytotoxic extract against leukemia L1210 cells with an IC 50 value of 1.9 μg/ml. Since, the fraction 2 of ethyl acetate extract was the most potent fraction, the irradiated samples were treated with the same procedure as treatment of fraction 2 from control sample. Cytotoxic activity test of fractions 2 from irradiated samples showed that the cytotoxic activity decreased depending on increasing of irradiation dose. Gamma irradiation dose up to 7.5 kGy on mahkota dewa leaves could decreased the cytotoxic activity of fraction 2 as the most cytotoxic-potential fraction against leukemia L1210 cells, but decreasing the cytotoxic activity has not exceeded the limit of the fraction declared inactive. So that the irradiation dose up to 7.5 kGy can be used for decontamination of bacteria and fungus/yeast without eliminating the cytotoxic activity. Gamma irradiation also caused changes in the thin layer chromatograph (TLC) spots and HPLC chromatograms profiles of fraction 2 which was the most cytotoxic fraction in ethyl acetate extract of mahkota dewa leaves against leukemia L1210 cells. One of the main peaks (peak 1) on HPLC chromatograms decreased with increasing the

Chromatogram Profiles and Cytotoxic Activity of Irradiated Mahkota Dewa (Phaleria Macrocarpa Scheff. Boerl Leaves

Directory of Open Access Journals (Sweden)

E. Katrin1

2011-04-01

Full Text Available Gamma irradiation has been used by the industries for preservation of herbal medicine, but it has not been studied the effect of gamma irradiation on their efficacy, especially their bioactivity as anticancer substances. The purpose of this research was to study the effect of gamma irradiation on the mahkota dewa leaves which has been claimed to contain potent anticancer substances. Maceration of dried mahkota dewa leaves successively with n-hexane, ethyl acetate, and ethanol gave crude extracts which the ethyl acetate was the most cytotoxic extract against leukemia L1210 cells with an inhibition concentration fifty (IC50 value of 10.3 µg/ml. Further separation of ethyl acetate extract by column chromatograph gave 7 fractions, and fraction 2 showed the most cytotoxic fraction exhibited the most cytotoxic extract against leukemia L1210 cells with an IC50 value of 1.9 µg/ml. Since, the fraction 2 of ethyl acetate extract was the most potent fraction, the irradiated samples were treated with the same procedure as treatment of fraction 2 from control sample. Cytotoxic activity test of fractions 2 from irradiated samples showed that the cytotoxic activity decreased depending on increasing of irradiation dose. Gamma irradiation dose up to 7.5 kGy on mahkota dewa leaves could decreased the cytotoxic activity of fraction 2 as the most cytotoxic-potential fraction against leukemia L1210 cells, but decreasing the cytotoxic activity has not exceeded the limit of the fraction declared inactive. So that the irradiation dose up to 7.5 kGy can be used for decontamination of bacteria and fungus/yeast without eliminating the cytotoxic activity. Gamma irradiation also caused changes in the thin layer chromatograph (TLC spots and HPLC chromatograms profiles of fraction 2 which was the most cytotoxic fraction in ethyl acetate extract of mahkota dewa leaves against leukemia L1210 cells. One of the main peaks (peak 1 on HPLC chromatograms decreased with increasing

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)

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.

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.

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.

Arsenic, cadmium, and manganese levels in shellfish from Map Ta Phut, an industrial area in Thailand, and the potential toxic effects on human cells.

Science.gov (United States)

Rangkadilok, Nuchanart; Siripriwon, Pantaree; Nookabkaew, Sumontha; Suriyo, Tawit; Satayavivad, Jutamaad

2015-01-01

Map Ta Phut Industrial Estate is a major industrial area in Thailand for both petrochemical and heavy industries. The release of hazardous wastes and other pollutants from these industries increases the potential for contamination in foods in the surrounding area, especially farmed shellfish. This study determined the arsenic (As), cadmium (Cd), and manganese (Mn) concentrations in the edible flesh of farmed shellfish, including Perna viridis, Meretrix meretrix, and Scapharca inaequivalvis, around the Map Ta Phut area using inductively coupled plasma mass spectrometry. The results showed that shellfish samples contained high levels of total As [1.84-6.42 mg kg(-1) wet weight (ww)]. High Mn concentrations were found in P. viridis and M. meretrix, whereas S. inaequivalis contained the highest Cd. Arsenobetaine (AsB) was found to be the major As species in shellfish (>45% of total As). The in vitro cytotoxicity of these elements was evaluated using human cancer cells (T47D, A549, and Jurkat cells). An observed decrease in cell viability in T47D and Jurkat cells was mainly caused by exposure to inorganic As (iAs) or Mn but not to AsB or Cd. The combined elements (AsB+Mn+Cd) at concentrations predicted to result from the estimated daily intake of shellfish flesh by the local people showed significant cytotoxicity in T47D and Jurkat cells.

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.

Identification of stable cytotoxic factors in the gas phase extract of cigarette smoke and pharmacological characterization of their cytotoxicity.

Science.gov (United States)

Noya, Yoichi; Seki, Koh-Ichi; Asano, Hiroshi; Mai, Yosuke; Horinouchi, Takahiro; Higashi, Tsunehito; Terada, Koji; Hatate, Chizuru; Hoshi, Akimasa; Nepal, Prabha; Horiguchi, Mika; Kuge, Yuji; Miwa, Soichi

2013-12-06

-dependent cytotoxicity with an EC50 value of 264.0±16.9μM (n=3). The concentrations of acrolein, MVK and CPO in the CSE were 3368±334, 2429±123 and 392.9±31.8μM (n=4), respectively, which were higher than the cytotoxic concentrations. The cytotoxicity of acrolein and MVK consisted of plasma membrane damage and decreased cell viability: the plasma membrane damage was totally prevented by treatment with an inhibitor of PKC or NOX, whereas the decreased cell viability was only partially prevented by these inhibitors. The cytotoxicity of CPO consisted only of decreased cell viability, which was totally resistant to these inhibitors. These results show that acrolein and MVK are responsible for the acute cytotoxicity of the CSE through PKC/NOX-dependent and -independent mechanisms, whereas CPO is responsible for the delayed cytotoxicity of the CSE through a PKC/NOX-independent mechanism. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

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

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

Pathogenic prion protein is degraded by a manganese oxide mineral found in soils

Science.gov (United States)

Russo, F.; Johnson, C.J.; McKenzie, D.; Aiken, Judd M.; Pedersen, J.A.

2009-01-01

Prions, the aetiological agents of transmissible spongiform encephalopathies, exhibit extreme resistance to degradation. Soil can retain prion infectivity in the environment for years. Reactive soil components may, however, contribute to the inactivation of prions in soil. Members of the birnessite family of manganese oxides (MnO2) rank among the strongest natural oxidants in soils. Here, we report the abiotic degradation of pathogenic prion protein (PrPTSE) by a synthetic analogue of naturally occurring birnessite minerals. Aqueous MnO2 suspensions degraded the PrPTSE as evidenced by decreased immunoreactivity and diminished ability to seed protein misfolding cyclic amplification reactions. Birnessite-mediated PrPTSE degradation increased as a solution's pH decreased, consistent with the pH-dependence of the redox potential of MnO2. Exposure to 5.6 mg MnO2 ml-1 (PrPTSE:MnO2=1 : 110) decreased PrPTSE levels by ???4 orders of magnitude. Manganese oxides may contribute to prion degradation in soil environments rich in these minerals. ?? 2009 SGM.

Influence of manganese fertilizer on efficiency of grapes on sandy soils of the Chechen Republic

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Batukaev A.A.

2014-01-01

Full Text Available As a result of the studies, there has been obtained new information about the manganese influence on productivity of grape plantations, on sandy soils of the Chechen Republic. Manganese fertilizing of 4 kg active ingredient per 1 ha, against the background of nitrogen 90 kg, phosphorus 90 kg and potassium 90 kg/ha, made it into a phase of grape sap flow, which contributes to higher yields, increase of the sugar content of the berries and a significant decrease in juice acidity, in comparison with other options.

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.

Aluminium alleviates manganese toxicity to rice by decreasing root symplastic Mn uptake and reducing availability to shoots of Mn stored in roots.

Science.gov (United States)

Wang, Wei; Zhao, Xue Qiang; Hu, Zhen Min; Shao, Ji Feng; Che, Jing; Chen, Rong Fu; Dong, Xiao Ying; Shen, Ren Fang

2015-08-01

Manganese (Mn) and aluminium (Al) phytotoxicities occur mainly in acid soils. In some plant species, Al alleviates Mn toxicity, but the mechanisms underlying this effect are obscure. Rice (Oryza sativa) seedlings (11 d old) were grown in nutrient solution containing different concentrations of Mn(2+) and Al(3+) in short-term (24 h) and long-term (3 weeks) treatments. Measurements were taken of root symplastic sap, root Mn plaques, cell membrane electrical surface potential and Mn activity, root morphology and plant growth. In the 3-week treatment, addition of Al resulted in increased root and shoot dry weight for plants under toxic levels of Mn. This was associated with decreased Mn concentration in the shoots and increased Mn concentration in the roots. In the 24-h treatment, addition of Al resulted in decreased Mn accumulation in the root symplasts and in the shoots. This was attributed to higher cell membrane surface electrical potential and lower Mn(2+) activity at the cell membrane surface. The increased Mn accumulation in roots from the 3-week treatment was attributed to the formation of Mn plaques, which were probably related to the Al-induced increase in root aerenchyma. The results show that Al alleviated Mn toxicity in rice, and this could be attributed to decreased shoot Mn accumulation resulting from an Al-induced decrease in root symplastic Mn uptake. The decrease in root symplastic Mn uptake resulted from an Al-induced change in cell membrane potential. In addition, Al increased Mn plaques in the roots and changed the binding properties of the cell wall, resulting in accumulation of non-available Mn in roots. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

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.

Phase transformations in low-carbon manganese steel 6Mn16

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J. Lis

2009-01-01

Full Text Available The kinetics of phase transformations of the austenite of 6Mn16 steel during continuous cooling are presented in a CCT diagram. Manganese partitioning between ferrite and austenite during intercritical annealing is enhanced by prior soft annealing. Due to the increased Mn concentration in austenite, the temperatures BS and MS have decreased, as compared to those achieved during cooling from the complete austenite region.

Comparative cytotoxic and genotoxic potential of 13 drinking water disinfection by-products using a microplate-based cytotoxicity assay and a developed SOS/umu assay.

Science.gov (United States)

Zhang, Shao-Hui; Miao, Dong-Yue; Tan, Li; Liu, Ai-Lin; Lu, Wen-Qing

2016-01-01

The implications of disinfection by-products (DBPs) present in drinking water are of public health concern because of their potential mutagenic, carcinogenic and other toxic effects on humans. In this study, we selected 13 main DBPs found in drinking water to quantitatively analyse their cytotoxicity and genotoxicity using a microplate-based cytotoxicity assay and a developed SOS/umu assay in Salmonella typhimurium TA1535/pSK1002. With the developed SOS/umu test, eight DBPs: 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-fura3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone (MX), dibromoacetonitrile (DBN), iodoacetic acid (IA), bromochloroacetonitrile (BCN), bromoacetic acid (BA), trichloroacetonitrile (TCN), dibromoacetic acid (DBA) and dichloroacetic acid (DCA) were significantly genotoxic to S. typhimurium. Three DBPs: chloroacetic acid (CA), trichloroacetic acid (TCA) and dichloroacetonitrile (DCN) were weakly genotoxic, whereas the remaining DBPs: chloroacetonitrile (CN) and chloral hydrate (CH) were negative. The rank order in decreasing genotoxicity was as follows: MX > DBN > IA > BCN > BA > TCN > DBA > DCA > CA, TCA, DCN > CN, CH. MX was approximately 370 000 times more genotoxic than DCA. In the microplate-based cytotoxicity assay, cytotoxic potencies of the 13 DBPs were compared and ranked in decreasing order as follows: MX > IA > DBN > BCN > BA > TCN > DCN > CA > DCA > DBA > CN > TCA > CH. MX was approximately 19 200 times more cytotoxic than CH. A statistically significant correlation was found between cytotoxicity and genotoxicity of the 13 DBPs in S. typhimurium. Results suggest that microplate-based cytotoxicity assay and the developed SOS/umu assay are feasible tools for analysing the cytotoxicity and genotoxicity of DBPs, particularly for comparing their toxic intensities quantitatively. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e

Cytotoxic bibenzyl dimers from the stems of Dendrobium fimbriatum Hook.

Science.gov (United States)

Xu, Feng-Qing; Xu, Fang-Cheng; Hou, Bo; Fan, Wei-Wei; Zi, Cheng-Ting; Li, Yan; Dong, Fa-Wu; Liu, Yu-Qing; Sheng, Jun; Zuo, Zhi-Li; Hu, Jiang-Miao

2014-11-15

The bioassay-guided chemical investigation of the stems of Dendrobium fimbriatum Hook led to the isolation of seven first reported bibenzyl dimers with a linkage of a methylene moiety, fimbriadimerbibenzyls A-G (1-7), together with a new dihydrophenanthrene derivative (S)-2,4,5,9-tetrahydroxy-9,10-dihydrophenanthrene (8) and thirteen known compounds (9-21). The structure of the new compound was established by spectroscopic analysis. Biological evaluation of bibenzyl derivatives against five human cell lines indicated that seven of those compounds exhibited broad-spectrum and cytotoxic activities with IC50 values ranging from 2.2 to 21.2 μM. Those rare bibenzyl dimers exhibited cytotoxic activities in vitro and the cytotoxicity decreased as the number of oxygen-containing groups in the structure decreases. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

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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 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).

Dendritic cells decreased the concomitant expanded Tregs and Tregs related IL-35 in cytokine-induced killer cells and increased their cytotoxicity against leukemia cells.

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Ying Pan

Full Text Available Regulatory T cells (Tregs are potent immunosuppressive cells and essential for inducing immune tolerance. Recent studies have reported that Tregs and Tregs related cytokines can inhibit the antitumor activity of cytokine-induced killer (CIK cells, but dendritic cells co-cultured CIK (DC-CIK cells can be used for induction of a specific immune response by blocking of Tregs and TGF-β, IL-10. As a novel identified cytokine, IL-35 is specially produced by Tregs and plays an essential role in immune regulation. However, it remains unknown whether IL-35 roles in tumor immunotherapy mediated by CIK and DC-CIK cells. In this study, we cultured CIK and DC-CIK cells from the same healthy adult samples, and investigated their phenotype, proliferation, cytotoxic activity against leukemia cell lines K562 and NB4 by FCM and CCK-8, measured IL-35, TGF-β and IL-10 protein by ELISA, detected Foxp3, IL-35 and IL-35 receptor mRNA by Real-time PCR, respectively. We found Tregs and IL-35 concomitantly expanded by a time-dependent way during the generation of CIK cells, but DC significantly down-regulated the expression of them and simultaneously up-regulated the proliferation ability as well as cytotoxic activity of CIK cells against leukemia cell lines. Therefore, our data suggested that DC decreased concomitant expanded Tregs and Tregs related IL-35 in CIK cells and might contribute to improve their cytotoxicity against leukemia cells in vitro.

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)

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.

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.

Suppression of natural killer cell cytotoxicity in postpartum women: time course and potential mechanisms.

Science.gov (United States)

Groer, Maureen W; El-Badri, Nagwa; Djeu, Julie; Williams, S Nicole; Kane, Bradley; Szekeres, Karoly

2014-07-01

Little is known about the recovery of the immune system from normal pregnancy and whether the postpartum period is a uniquely adapted immune state. This report extends previous observations from our group of decreased natural killer (NK) cell cytotoxicity in the postpartum period. NK cytotoxicity was measured from 1 week through 9 months postpartum. In addition, NK cytotoxicity was assayed in the presence or absence of pooled plasmas collected from either postpartum or nonpostpartum women. Samples of cells were stained for inhibitory receptors and analyzed by flow cytometry. NK cytotoxicity remained decreased in postpartum women compared to controls through the first 6 postpartum months, returned to normal levels by 9 months, and remained normal at 12 months. NK cytotoxicity during the first 6 months was further inhibited by the addition of pooled plasma to NK cultures from postpartum women, but the addition of pooled plasma from the control group did not affect that group's NK cultures. There were differences in inhibitory receptor staining between the two groups, with decreased CD158a and CD158b and increased NKG2A expression on postpartum NK cells during the first 3 postpartum months. These data suggest that NK cytotoxicity postpartum inhibition lasts 6 months and is influenced by unidentified postpartum plasma components. The effect may also involve receptors on NK cells. © The Author(s) 2013.

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

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.

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

The future of cytotoxic therapy: selective cytotoxicity based on biology is the key

International Nuclear Information System (INIS)

Bono, Johann S de; Tolcher, Anthony W; Rowinsky, Eric K

2003-01-01

Although mortality from breast cancer is decreasing, 15% or more of all patients ultimately develop incurable metastatic disease. It is hoped that new classes of target-based cytotoxic therapeutics will significantly improve the outcome for these patients. Many of these novel agents have displayed cytotoxic activity in preclinical and clinical evaluations, with little toxicity. Such preferential cytotoxicity against malignant tissues will remain tantamount to the Holy Grail in oncologic therapeutics because this portends improved patient tolerance and overall quality of life, and the capacity to deliver combination therapy. Combinations of such rationally designed target-based therapies are likely to be increasingly important in treating patients with breast carcinoma. The anticancer efficacy of these agents will, however, remain dependent on the involvement of the targets of these agents in the biology of the individual patient's disease. Results of DNA microarray analyses have raised high hopes that the analyses of RNA expression levels can successfully predict patient prognosis, and indicate that the ability to rapidly 'fingerprint' the oncogenic profile of a patient's tumor is now possible. It is hoped that these studies will support the identification of the molecules driving a tumor's growth, and the selection of the appropriate combination of targeted agents in the near future

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.

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

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.

Gastroprotective Properties of Manganese Chloride on Acetic Acid

African Journals Online (AJOL)

Dr Olaleye

Drugs with multiple mechanisms of protective action may be effective in minimizing ... that Manganese had dose and treatment duration dependent effect on healing of ulcerated stomach. .... The stomach was bathed with normal saline ..... Arnaud, J., and Favier, A. (1995): "Copper, iron, manganese ... Experimental Toxic.

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.

Redox-responsive manganese dioxide nanoparticles for enhanced MR imaging and radiotherapy of lung cancer

Science.gov (United States)

Cho, Mi Hyeon; Choi, Eun-Seok; Kim, Sehee; Goh, Sung-Ho; Choi, Yongdoo

2017-12-01

In this study, we synthesized manganese dioxide nanoparticles (MnO2 NPs) stabilized with biocompatible polymers (polyvinylpyrrolidone and polyacrylic acid) and analyzed their effect on non-small cell lung cancer (NSCLC) cells with or without gefitinib resistance in vitro. MnO2 NPs showed glutathione (GSH)-responsive dissolution and subsequent enhancement in magnetic resonance (MR) imaging. Of note, treatment with MnO2 NPs induced significant cytotoxic effects on NSCLC cells, and additional dose-dependent therapeutic effects were obtained upon X-ray irradiation. Normal cells treated with MnO2 NPs were viable at the tested concentrations. In addition, increased therapeutic efficacy could be achieved when the cells were treated with MnO2 NPs in hypoxic conditions. Therefore, we conclude that the use of MnO2 NPs in MR imaging and combination radiotherapy may be an efficient strategy for the imaging and therapy of NSCLC.

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,

Mesoporous titanium-manganese dioxide for sulphur mustard and soman decontamination

Energy Technology Data Exchange (ETDEWEB)

Stengl, Vaclav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 250 68 Rez (Czech Republic); Bludska, Jana [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 250 68 Rez (Czech Republic); Oplustil, Frantisek; Nemec, Tomas [Military Technical Institute of Protection Brno, Veslarska 230, 628 00 Brno (Czech Republic)

2011-11-15

Highlights: {yields} New nano-dispersive materials for warfare agents decontamination. {yields} 95% decontamination activities for sulphur mustard. {yields} 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{sup 4+} content affects the decontamination activity; with increasing Mn{sup 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{sub 3}7 with 18.6 wt.% Mn and TiMn{sub 5} with 2.1 wt.% Mn, respectively.

Heavy metal pollution among autoworkers. II. Cadmium, chromium, copper, manganese, and nickel

Energy Technology Data Exchange (ETDEWEB)

Clausen, J.; Rastogi, S.C.

1977-08-01

Garages and auto-repair workshops may be polluted with other heavy metals besides lead. Blood of autoworkers with high lead content was analyzed for cadmium, chromium, copper, manganese, nickel, ALAD activity and carboxyhaemoglobin level. Cadmium and copper levels in blood of autoworkers were comparable with those of the control subjects while chromium and nickel levels were significantly higher (P < 0.01 for both metals), and scattered raised values of manganese were found. There was no significant mutual correlation between levels of various heavy metals determined in whole blood. High copper levels were slightly related to decreasing ALAD activity (P < 0.1). Nineteen percent of autoworkers were found to have an abnormally high blood level of carboxyhemoglobin. The amount of particulate heavy metal in autoworkshop air was not related to biochemical abnormalities found in the autoworkers. Various sources of pollution of these heavy metals in autoworkshops are discussed.

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.

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...

Source of cytotoxicity in a colloidal silver nanoparticle suspension.

Science.gov (United States)

Hatipoglu, Manolya Kukut; Keleştemur, Seda; Altunbek, Mine; Culha, Mustafa

2015-05-15

Silver nanoparticles (AgNPs) are increasingly used in a variety of applications because of their potential antimicrobial activity and their plasmonic and conductivity properties. In this study, we investigated the source of cytotoxicity, genotoxicity, and reactive oxygen species (ROS) production on human dermal fibroblast and human lung cancer (A549) cell lines upon exposure to AgNP colloidal suspensions prepared with the simplest and most commonly used Lee–Meisel method with a variety of reaction times and the concentrations of the reducing agent. The AgNPs synthesized with shorter reaction times were more cytotoxic and genotoxic due to the presence of a few nanometer-sized AgNP seeds. The suspensions prepared with an increased citrate concentration were not cytotoxic, but they induced more ROS generation on A549 cells due to the high citrate concentration. The genotoxicity of the suspension decreased significantly at the higher citrate concentrations. The analysis of both transmission electron microscopy images from the dried droplet areas of the colloidal suspensions and toxicity data indicated that the AgNP seeds were the major source of toxicity. The completion of the nucleation step and the formation of larger AgNPs effectively decreased the toxicity.

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.

Cytotoxicity of an 125I-labelled DNA ligand

International Nuclear Information System (INIS)

Karagiannis, T.C.; Lobachevsky, P.N.; Martin, R.F.

2000-01-01

The subcellular distribution and cytotoxicity of a DNA-binding ligand [ 125 I]-Hoechst 33258 following incubation of K562 cells with the drug was investigated. The ability of a radical scavenger, dimethyl sulphoxide, to protect cells from the 125 I-decay induced cell death was also studied. Three different concentrations and specific activities of the drug were used to provide different ligand : DNA binding ratios. The results demonstrated a trend toward improved delivery of the ligand to the nucleus and to chromatin at higher ligand concentrations, with concomitant increased sensitivity to 125 I-decay induced cytotoxicity and decreased protection by dimethyl sulphoxide. This correlation of radiobiological parameters with subcellular drug distribution is consistent with the classical dogma that attributes cytotoxicity to DNA double-stranded breakage in the vicinity of the site of decay, where the high LET nature of the damage confers minimal sensitivity to radical scavenging

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.

Fast intracellular dissolution and persistent cellular uptake of silver nanoparticles in CHO-K1 cells: implication for cytotoxicity

DEFF Research Database (Denmark)

Jiang, Xiumei; Miclaus, Teodora; Wang, Liming

2015-01-01

. Subsequent cytotoxicity studies show that Ag NPs decrease cell viability and increase ROS production. Pre-incubation with N-acetyl-l-cysteine, an efficient antioxidant and Ag+ chelator, diminished the cytotoxicity caused by Ag NPs or Ag+ exposure. Our study suggests that the cytotoxicity mechanism of Ag NPs...

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.

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

Decreased helenalin-induced cytotoxicity by flavonoids from Arnica as studied in a human lung carcinoma cell line

NARCIS (Netherlands)

Woerdenbag, HJ; Merfort, [No Value; Schmidt, TJ; Passreiter, CM; Willuhn, G; vanUden, W; Pras, N; Konings, AWT

1995-01-01

The effect of the flavones apigenin, luteolin, hispidulin and eupafolin, and of the flavonols kaempferol, quercetin, 6-methoxykaempferol and patuletin from Amica spp, on the cytotoxicity of the sesquiterpene lactone helenalin was studied in the human lung carcinoma cell line GLC(4) using the

Fixation and localisation of manganese in some soft water organisms: I - Distribution of 54Mn in an ecologic system in fresh water; II - study by biochemical fractionation of manganese contained by isolated plant cells

International Nuclear Information System (INIS)

Magnaval, Robert; Lachet, Bernard; Gagnaire, Janine; Fourcy, Andre; Neuburger, Michel; Fer, Andre

1968-12-01

After having recalled that Manganese 54, an irradiation product of 54 Fe, has a sufficiently long radioactive period to be detected in atmospheric fallouts of nuclear explosions, but also in radioactive wastes produced by research centres, and is generally produced by corrosion of any enclosure submitted to neutron irradiation, the authors report the experimental study of a radioactive pollution of fresh water when this radio-element is a component of this pollution. Different containers are considered. They contain either water and sediments, or water and organic compounds and aquatic plants, or water and sediments and aquatic plants. A solution of 54 MnCl 2 of radioactive pollution is introduced in these containers and the authors study the decrease of radioactivity in water with respect to the considered ecosystem, the 54 Mn concentration in aquatic living species, and the distribution of 54 Mn after 43 days. In a second part, they report the study of the distribution of cellular manganese in isolated biochemical fractions by using the Schmidt and Thannhauser method. Due to the low content, the detection of this mineral nutrient requires a highly sensitive method: dosing of natural manganese by radio-activation

An altered gp100 peptide ligand with decreased binding by TCR and CD8alpha dissects T cell cytotoxicity from production of cytokines and activation of NFAT

Directory of Open Access Journals (Sweden)

Niels eSchaft

2013-09-01

Full Text Available Altered peptide ligands (APLs provide useful tools to study T cell activation and potentially direct immune responses to improve treatment of cancer patients. To better understand and exploit APLs, we studied the relationship between APLs and T cell function in more detail. Here, we tested a broad panel of gp100(280-288 APLs with respect to T cell cytotoxicity, production of cytokines and activation of Nuclear Factor of Activated T cells (NFAT by human T cells gene-engineered with a gp100-HLA-A2-specific TCRalpha/beta. We demonstrated that gp100-specific cytotoxicity, production of cytokines, and activation of NFAT were not affected by APLs with single amino acid substitutions, except for an APL with an amino acid substitution at position 3 (APL A3, which did not elicit any T cell response. A gp100 peptide with a double amino acid mutation (APL S4S6 elicited T cell cytotoxicity and production of IFNgamma, and to a lesser extent TNFalpha, IL-4, and IL-5, but not production of IL-2 and IL-10, or activation of NFAT. Notably, TCR-mediated functions showed decreases in sensitivities for S4S6 versus gp100 wt peptide, which were minor for cytotoxicity but at least a 1000-fold more prominent for the production of cytokines. TCR-engineered T cells did not bind A3-HLA-A2, but did bind S4S6-HLA-A2 although to a lowered extent compared to wt peptide-HLA-A2. Moreover, S4S6-induced T cell function demonstrated an enhanced dependency on CD8alpha. Taken together, most gp100 APLs functioned as agonists, but A3 and S4S6 peptides acted as a null ligand and partial agonist, respectively. Our results further suggest that TCR-mediated cytotoxicity can be dissected from production of cytokines and activation of NFAT, and that the agonist potential of peptide mutants relates to the extent of binding by TCR and CD8alpha. These findings may facilitate the design of APLs to advance the study of T cell activation and their use for therapeutic applications.

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...

Electromagnetic characteristics of manganese oxide-coated Fe3O4 nanoparticles at 2-18 GHz

Science.gov (United States)

Yang, R. B.; Liang, W. F.; Lin, C. K.

2011-04-01

The dielectric and magnetic properties of manganese oxide-coated Fe3O4 nanoparticles (NPs) were measured by the transmission/reflection method in 2-18 GHz. MnOx-coated Fe3O4 NPs were prepared by sol-gel method followed by heat-treating at 300, 400, and 500 °C, respectively. The heat-treated powders were then used as magnetic fillers and added to an epoxy resin to prepare MnOx-coated Fe3O4 composites for the complex permittivity (ɛ'-jɛ″) and permeability (μ'-jμ″) measurements. After the sol-gel process, the coating of manganese oxide (mixture of major Mn2O3 and minor Mn3O4) reduced the value of ɛ'. The lower the heat-treating temperature, the larger the decrease in ɛ'. The relative decrease in ɛ', compared with uncoated Fe3O4 nanoparticles, is 28.7, 23.5, and 20.0% for coated MnOx heat-treated at 300, 400, and 500 °C, respectively, while the relative decrease in ɛ″ is 74.1, 68.8, and 65.2%, respectively. In the present study, MnOx-coated Fe3O4 exhibited a significant decrease in dielectric loss tangent of ˜100% compared to that of uncoated NPs and can be of practical use for microwave components.

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.

Damping Capacity of High Manganese Austenitic Stainless Steel with a Two Phase Mixed Structure of Martensite and Austenite

International Nuclear Information System (INIS)

Hwang, Tae Hyun; Kang, Chang-Yong

2013-01-01

The damping capacity of high manganese austenitic stainless steel with a two phase mixed structure of deformation-induced martensite and reversed austenite was studied. Reversed austenite with an ultra-fine grain size of less than 0.2 μm was obtained by reversion treatment. The two phase structure of deformation-induced martensite and reversed austenite was obtained by annealing treatment at a range of 500-700 °C and various times in cold rolled high manganese austenitic stainless steel. The damping capacity increased with an increasing annealing temperature and time. In high manganese stainless steel with the two phase mixed structure of martensite and austenite, the damping capacity decreased with an increasing volume fraction of deformation-induced martensite. Thus, the damping capacity was strongly affected by deformation-induced martensite. The results confirmed that austenitic stainless steel with a good combination of strength and damping capacity was obtained from the two phase mixed structure of austenite and martensite.

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...

Effect of carbon and manganese on the microstructure and mechanical properties of 9Cr2WVTa deposited metals

Science.gov (United States)

Wang, Jian; Rong, Lijian; Li, Dianzhong; Lu, Shanping

2017-03-01

Six 9Cr2WVTa deposited metals with different carbon and manganese contents have been studied to reveal the role of major elements, which guide for the design of welding consumables for reduced activation ferritic/martensitic steel and meet for the requirements of accelerator driven systems-lead fusion reactors. The typical microstructure for the 9Cr2WVTa deposited metals is the lath martensite along with the fine stripe δ-ferrite. The chemical compositions influence the solidification sequence and therefore, change the δ-ferrite content in the deposited metal. The impact toughness for the 9Cr2WVTa deposited metals decreases remarkably when the δ-ferrite content is more than 5.2 vol%, also the impact toughness decreases owing to the high quenching martensite formation. Increasing the level of manganese addition, α phase of each alloy shifts to the bottom right according to the CCT diagram.

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.

A promising magnetic resonance stem cell tracer based on natural biomaterials in a biological system: manganese (II chelated to melanin nanoparticles

Directory of Open Access Journals (Sweden)

Liu SJ

2018-03-01

Full Text Available Shi-Jie Liu,1,2,* Ling-Jie Wang,1,* Ying Qiao,1 Hua Zhang,1 Li-Ping Li,1 Jing-Hua Sun,1 Sheng He,1 Wen Xu,1,2 Xi Yang,1 Wen-Wen Cai,2 Jian-Ding Li,1 Bin-Quan Wang,3 Rui-Ping Zhang2 1Medical Imaging Department, First Clinical Medical College of Shanxi Medical University, Taiyuan, Shanxi, China; 2Imaging Department, Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, China; 3Department of Otolaryngology, Head & Neck Surgery, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi, China *These authors contributed equally to the paper Background: Melanin and manganese are both indispensable natural substances that play crucial roles in the human body. Melanin has been used as a multimodality imaging nanoplatform for biology science research because of its natural binding ability with metal ions (eg, 64Cu2+, Fe3+, and Gd3+. Because of its effects on T1 signal enhancement, Mn-based nanoparticles have been used in magnetic resonance (MR quantitative cell tracking in vivo. Stem cell tracking in vivo is an essential technology used to characterize engrafted stem cells, including cellular viability, biodistribution, differentiation capacity, and long-term fate.Methods: In the present study, manganese(II ions chelated to melanin nanoparticles [MNP-Mn(II] were synthesized. The characteristics, stem cell labeling efficiency, and cytotoxicity of the nanoparticles were evaluated. MR imaging of the labeled stem cells in vivo and in vitro were also further performed. In T1 relaxivity (r1, MNP-Mn(II were significantly more abundant than Omniscan. Bone marrow-derived stem cells (BMSCs can be labeled easily by coincubating with MNP-Mn(II, suggesting that MNP-Mn(II had high biocompatibility.Results: Cell Counting Kit-8 assays revealed that MNP-Mn(II had almost no cytotoxicity when used to label BMSCs, even with a very high concentration (1,600 µg/mL. BMSCs labeled with MNP-Mn(II could generate a hyperintense T1 signal both in vitro

Engineering of dendrimer surfaces to enhance transepithelial transport and reduce cytotoxicity.

Science.gov (United States)

Jevprasesphant, Rachaneekorn; Penny, Jeffrey; Attwood, David; McKeown, Neil B; D'Emanuele, Antony

2003-10-01

To evaluate the cytotoxicity, permeation, and transport mechanisms of PAMAM dendrimers and surface-modified cationic PAMAM dendrimers using monolayers of the human colon adenocarcinoma cell line, Caco-2. Cytotoxicity was determined using the MTT assay. The effect of dendrimers on monolayer integrity was determined from measurements of transepithelial electrical resistance (TEER) and [14C]mannitol apparent permeability coefficient (Papp). The Papp of dendrimers through monolayers was measured in both the apical (A)-to-basolateral (B) and B --> A directions at 4 degrees C and 37 degrees C and also in the presence and absence of ethylenediamine tetraacetic acid (EDTA) and colchicine. The cytotoxicity and permeation of dendrimers increased with both concentration and generation. The cytotoxicity of cationic dendrimers (G2, G3, G4) was greater than that of anionic dendrimers (G2.5, G3.5) but was reduced by conjugation with lauroyl chloride: the least cytotoxic conjugates were those with six attached lauroyl chains. At 37 degrees C the Papp of cationic dendrimers was higher than that of anionic dendrimers and, in general, increased with the number of attached lipid chains. Cationic dendrimers decreased TEER and significantly increased the Papp of mannitol. Modified dendrimers also reduced TEER and caused a more marked increase in the Papp of mannitol. The Papp values of dendrimers and modified dendrimers were higher in the presence of EDTA, lower in the presence of colchicine, and lower at 4 degrees C than at 37 degrees C. The properties of dendrimers may be significantly modified by surface engineering. Conjugation of cationic PAMAM dendrimers with lauroyl chloride decreased their cytotoxicity and increased their permeation through Caco-2 cell monolayers. Both PAMAM dendrimers and lauroyl-PAMAM dendrimer conjugates can cross epithelial monolayers by paracellular and transcellular pathways.

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

The effect of gamma irradiation on cytotoxic activity of the flesh of Mahkota Dewa (Phaleria macrocarpa (Scheff) Boerl) Fruits

International Nuclear Information System (INIS)

Ermin K Winarno; Mazda; Hindra Rahmawati; Hendig Winarno

2010-01-01

Gamma irradiation had been used by herbs medicine industries for preservation of medicinal plants, but the effect of irradiation on their bioactivities has not been observed. The purpose of this research was to obtain the optimum radiation dose for the preservation of mahkota dewa flesh fruits without damaging their cytotoxic activities. To evaluate the effect of irradiation, dried samples of flesh fruit of mahkota dewa were irradiated at various doses of 0; 5; 7.5; 10; 15 and 20 kGy. Microbial contamination was tested using Indonesian National Standard method, which indicated that all microbes were killed at the dose of 5 kGy. Each sample was macerated with ethanol, and the extracts obtained were then fractionated with column chromatography, from which 8 fractions were obtained. Cytotoxicity test of the fractions against leukemia L1210 cells, showed that the Fr.3 was the most cytotoxic. To determine optimal irradiation dose to inhibit and to kill bacteria and yeast/mold in the mahkota dewa flesh fruit samples without decreasing cytotoxic activity, a thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) analysis of the Fr.3 were done. The results showed that the doses of ≥ 5 kGy inhibited the growth and killed all the bacteria, yeast and mold without decreasing significantly the cytotoxic activity of ethanol extract against leukemia L1210 cell. The significant decrease of cytotoxic against leukemia L1210 of ethanol extract were occurred after ≥ 10 kGy irradiation of the samples. At the dose of 10 kGy, the cytotoxicity decreased even though it was not exceeded the limit of the fraction was declared inactive. Analysis of thin layer chromatogram profiles showed that the Fr.3 contained at least 10 components. Irradiation until the dose of 20 kGy decreased the major peak intensity. with the increasing of irradiation doses. It was concluded that the dose of 5 kGy to 10 kGy were the optimum dose for the preservation of flesh fruit of

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.

Cisplatin Induces Cytotoxicity through the Mitogen-Activated Protein Kinase Pathways ana Activating Transcription Factor 3

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Carly St. Germain

2010-07-01

Full Text Available The mechanisms underlying the proapoptotic effect of the chemotherapeutic agent, cisplatin, are largely undefined. Understanding the mechanisms regulating cisplatin cytotoxicity may uncover strategies to enhance the efficacy of this important therapeutic agent. This study evaluates the role of activating transcription factor 3 (ATF3 as a mediator of cisplatin-induced cytotoxicity. Cytotoxic doses of cisplatin and carboplatin treatments consistently induced ATF3 expression in five tumor-derived cell lines. Characterization of this induction revealed a p53, BRCA1, and integrated stress response-independent mechanism, all previously implicated in stress-mediated ATF3 induction. Analysis of mitogenactivated protein kinase (MAPK pathway involvement in ATF3 induction by cisplatin revealed a MAPK-dependent mechanism. Cisplatin treatment combined with specific inhibitors to each MAPK pathway (c-Jun N-terminal kinase, extracellularsignal-regulated kinase, and p38 resulted in decreasedATF3 induction at the protein level. MAPK pathway inhibition led to decreased ATF3 messenger RNA expression and reduced cytotoxic effects of cisplatin as measured by the 3-(4,5-dimethylthiazol-2-ylF2,5-diphenyltetrazolium bromide cell viability assay. In A549 lung carcinoma cells, targeting ATF3 with specific small hairpin RNA also attenuated the cytotoxic effects of cisplatin. Similarly, ATF3-/murine embryonic fibroblasts (MEFs were shown to be less sensitive to cisplatin-induced cytotoxicity compared with ATF3+/+ MEFs. This study identifies cisplatin as a MAPK pathway-dependent inducer of ATF3, whose expression influences cisplatin’s cytotoxic effects.

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.

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)

Effect of citral on the cytotoxicity of doxorubicin in human B-lymphoma cells.

Science.gov (United States)

Dangkong, Darinee; Limpanasithikul, Wacharee

2015-02-01

Doxorubicin is a chemotherapy agent used in non-Hodgkin's lymphoma but side effects limit its use. Citral is a mixture of neral and geranial found in essential oils of lemon grass. We evaluated the activity of citral, doxorubicin, and combination on cytotoxicity, apoptosis, and anti-proliferative effects using human lymphoma Ramos cells. Cells were treated with doxorubicin alone or in combination with citral (10, 20, and 40 μM). Cytotoxic and apoptosis studies were done after 24 and 18 h incubations, respectively. Cytotoxic effects of citral on normal human peripheral blood mononuclear cells (PBMCs) were also investigated for its safety. Changes in the expression of BCL-2 family genes were analyzed by quantitative RT-PCR. Citral had cytotoxicity on cells with an IC50 value of 77.19 ± 4.95 µM. Citral at concentrations of 10, 20, and 40 µM additively increased the cytotoxic and apoptotic effects of doxorubicin, leading to decreased IC50 (µM) of the drug from 2.50 ± 0.01 to 2.16 ± 0.03, 1.90 ± 0.04, and 1.23 ± 0.04, respectively. Enhanced cytotoxicity was not observed in normal human PBMCs. Citral (40 µM) in combination with doxorubicin (1.5 µM) increased the expression of pro-apoptotic protein BAK but significantly decreased the expression of anti-apoptotic protein BCL-XL to 5.26-fold compared with doxorubicin-treated cells. It did not change the anti-proliferative activity of drug. Citral potentiated cytotoxicity of doxorubicin by increasing apoptotic effects. We conclude that citral may have beneficial effects in patients with B cell lymphoma treated with chemotherapy.

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.

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

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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

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

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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)

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.

Synchrotron-Based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment

Science.gov (United States)

Plant species differ in response to high available manganese (Mn), but the mechanisms of sensitivity and tolerance are poorly understood. In solution culture, greater than or equal to 30 µM Mn decreased the growth of soybean (Glycine max), but white lupin (Lupinus albu...

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

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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.

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)

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

Modification of the cytotoxic activity of mitomycin C

International Nuclear Information System (INIS)

Marshall, R.S.; Rauth, A.M.

1985-01-01

Utilizing a system in which oxygen levels could be altered and monitored during acute drug exposures, the authors have begun to characterize the cellular and molecular damage produced by MMC in CHO cells. The cytotoxic activity of MMC decreases sharply from 0 to 0.1% oxygen in solution, while from 0.1 to 20.0% there is little change. DNA crosslinking in cells was examined under these conditions by alkaline elution and found to be directly correlated with cell killing. While hypoxia increased crosslinking, significant levels were still observed under aerobic conditions. A cell-free assay for alkylation confirmed that overall levels increase in the absence of oxygen; however, negligible alkylation was observed under aerobic conditions. It was also noted that ascorbic acid present in the exposure medium (0.284 mM) increased the aerobic cytotoxicity without altering the hypoxic cytotoxicity. The present data suggest that MMC can be activated to an alkylating species by two mechanisms, one oxygen sensitive and one oxygen insensitive and that these two mechanisms may be independently modified

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 Effect of Soil Manganese on Japanese Larch (Larix Leptolepis Sieb. and Zucc.) Seedlings in the Greenhouse

Science.gov (United States)

Callie Jo Schweitzer; William E. Sharpe; Pamela J. Edwards

1999-01-01

Preliminary analysis of 9 year old Japanese larch trees and soil subjected to appliitions of triple ambient annual nitrogen (N) and sulfur (S) deposftfon revealed elevated available soil and foliar manganese (Mn) levels and decreased growth compared to controls. A greenhouse study was conducted in which Japanese larch seedlings were grown in geld collected soil...

Oleic acid is a key cytotoxic component of HAMLET-like complexes.

Science.gov (United States)

Permyakov, Sergei E; Knyazeva, Ekaterina L; Khasanova, Leysan M; Fadeev, Roman S; Zhadan, Andrei P; Roche-Hakansson, Hazeline; Håkansson, Anders P; Akatov, Vladimir S; Permyakov, Eugene A

2012-01-01

HAMLET is a complex of α-lactalbumin (α-LA) with oleic acid (OA) that selectively kills tumor cells and Streptococcus pneumoniae. To assess the contribution of the proteinaceous component to cytotoxicity of HAMLET, OA complexes with proteins structurally and functionally distinct from α-LA were prepared. Similar to HAMLET, the OA complexes with bovine β-lactoglobulin (bLG) and pike parvalbumin (pPA) (bLG-OA-45 and pPA-OA-45, respectively) induced S. pneumoniae D39 cell death. The activation mechanisms of S. pneumoniae death for these complexes were analogous to those for HAMLET, and the cytotoxicity of the complexes increased with OA content in the preparations. The half-maximal inhibitory concentration for HEp-2 cells linearly decreased with rise in OA content in the preparations, and OA concentration in the preparations causing HEp-2 cell death was close to the cytotoxicity of OA alone. Hence, the cytotoxic action of these complexes against HEp-2 cells is induced mostly by OA. Thermal stabilization of bLG upon association with OA implies that cytotoxicity of bLG-OA-45 complex cannot be ascribed to molten globule-like conformation of the protein component. Overall, the proteinaceous component of HAMLET-like complexes studied is not a prerequisite for their activity; the cytotoxicity of these complexes is mostly due to the action of OA.

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

Effect of paramagnetic manganese ions doping on frequency and high temperature dependence dielectric response of layered Na1.9Li0.1Ti3O7 ceramics

International Nuclear Information System (INIS)

Pal, Dharmendra; Pandey, J.L.

2010-01-01

The manganese doped layered ceramic samples (Na 1.9 Li 0.1 )Ti 3 O 7 : XMn (0.01 ≤ X ≤ 0.1) have been prepared using high temperature solid state reaction. The room temperature electron paramagnetic resonance (EPR) investigations exhibit that at lower percentage of doping the substitution of manganese ions occur as Mn 3+ at Ti 4+ sites, whereas for higher percentage of doping Mn 2+ ions occupy the two different interlayer sodium/lithium sites. In both cases, the charge compensation mechanism should operate to maintain the overall charge neutrality of the lattice. The manganese doped derivatives of layered Na 1.9 Li 0. 1Ti 3 O 7 (SLT) ceramics have been investigated through frequency dependence dielectric spectroscopy in this work. The results indicate that the dielectric losses in these ceramics are the collective contribution of electric conduction, dipole orientation and space charge polarization. Smeared peaks in temperature dependence of permittivity plots suggest diffuse nature of high temperature ferroelectric phase transition. The light manganese doping in SLT enhances the dielectric constant. However, manganese doping decreases dielectric loss due to inhibition of domain wall motion, enhances electron-hopping conduction, and impedes the interlayer ionic conduction as well. Manganese doping also gives rise to contraction of interlayer space. (author)

Dynamics analysis of extraction of manganese intensified by electric field

Science.gov (United States)

Ma, Wenrui; Tao, Changyuan; Li, Huizhan; Liu, Zuohua; Liu, Renlong

2018-06-01

In this study, a process reinforcement technology for leaching process of pyrolusite was developed. The electric field was introduced to decrease reaction temperature and improve the leaching rate of pyrolusite. The mechanisms of electric field intensifying leaching process of pyrolusite were investigated through X-ray diffraction (XRD), and Brunauer Emmett Teller (BET) in detail. The results showed that the electric field could decrease obviously the apparent activation energy of leaching process of pyrolusite. The apparent activation energy of the leaching of pyrolusite intensified by electric field was calculated to be 53.76 kJ.mol-1. In addition, the leaching efficiency of manganese was effectively increased by 10% to 20% than that without electric field under the same conditions. This was because that the electron conduit between Fe (II)/Fe (III) and pyrite was dredged effectively by electric field.

High Manganese Tolerance and Biooxidation Ability of Serratia marcescens Isolated from Manganese Mine Water in Minas Gerais, Brazil

Directory of Open Access Journals (Sweden)

Natália R. Barboza

2017-10-01

Full Text Available Manganese is an important metal for the maintenance of several biological functions, but it can be toxic in high concentrations. One of the main forms of human exposure to metals, such as manganese (Mn, is the consumption of solar salt contaminated. Mn-tolerant bacteria could be used to decrease the concentration of this metal from contaminated sites through safer environmental-friendly alternative technology in the future. Therefore, this study was undertaken to isolate and identify Mn resistant bacteria from water samples collected from a Mn mine in the Iron Quadrangle region (Minas Gerais, Brazil. Two bacterial isolates were identified as Serratia marcescens based on morphological, biochemical, 16S rDNA gene sequencing and phylogeny analysis. Maximum resistance of the selected isolates against increasing concentrations of Mn(II, up to 1200 mg L-1 was determined in solid media. A batch assay was developed to analyze and quantify the Mn removal capacities of the isolates. Biological Mn removal capacities of over 55% were detected for both isolates. Whereas that mechanism like biosorption, precipitation and oxidation could be explaining the Mn removal, we seek to give an insight into some of the molecular mechanisms adopted by S. marcescens isolates. For this purpose, the following approaches were adopted: leucoberbelin blue I assay, Mn(II oxidation by cell-free filtrate and electron microscopy and energy-dispersive X-ray spectroscopy analyses. Overall, these results indicate that S. marcescens promotes Mn removal in an indirect mechanism by the formation of Mn oxides precipitates around the cells, which should be further explored for potential biotechnological applications for water recycling both in hydrometallurgical and mineral processing operations.

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.

The effects of high dose of two manganese supplements (organic and inorganic) on the rumen microbial ecosystem.

Science.gov (United States)

Kišidayová, Svetlana; Pristaš, Peter; Zimovčáková, Michaela; Blanár Wencelová, Monika; Homol'ová, Lucia; Mihaliková, Katarína; Čobanová, Klaudia; Grešáková, Ľubomíra; Váradyová, Zora

2018-01-01

Little is known about the effects of the high dose and types of manganese supplements on rumen environment at manganese intake level close above the limit of 150 mg/kg of dry feed matter. The effects of high dose of two manganese supplements (organic and inorganic) on rumen microbial ecosystem after four months of treatment of 18 lambs divided into three treatment groups were studied. We examined the enzyme activities (α-amylase, xylanase, and carboxymethyl cellulase), total and differential microscopic counts of rumen ciliates, total microscopic counts of bacteria, and fingerprinting pattern of the eubacterial and ciliates population analyzed by PCR-DGGE. Lambs were fed a basal diet with a basal Mn content (34.3 mg/kg dry matter; control) and supplemented either with inorganic manganous sulfate or organic Mn-chelate hydrate (daily 182.7, 184 mg/kg dry matter of feed, respectively). Basal diet, offered twice daily, consisted of ground barley and hay (268 and 732 g/kg dry matter per animal and day). The rumens of the lambs harbored ciliates of the genera of Entodinium, Epidinium, Diplodinium, Eudiplodinium, Dasytricha, and Isotricha. No significant differences between treatment groups were observed in the total ciliate number, the number of ciliates at the genus level, as well as the total number of bacteria. Organic Mn did decrease the species richness and diversity of the eubacterial population examined by PCR-DGGE. No effects of type of Mn supplement on the enzyme activities were observed. In comparison to the control, α-amylase specific activities were decreased and carboxymethyl-cellulase specific activities were increased by the Mn supplements. Xylanase activities were not influenced. In conclusion, our results suggested that the intake of tested inorganic and organic manganese supplements in excess may affect the specific groups of eubacteria. More studies on intake of Mn supplements at a level close to the limit can reveal if the changes in microbial

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...

Influence of deposition time on the properties of chemical bath deposited manganese sulfide thin films

Directory of Open Access Journals (Sweden)

Anuar Kassim

2010-12-01

Full Text Available Manganese sulfide thin films were chemically deposited from an aqueous solution containing manganese sulfate, sodium thiosulfate and sodium tartrate. The influence of deposition time (2, 3, 6 and 8 days on the properties of thin films was investigated. The structure and surface morphology of the thin films were studied by X-ray diffraction and atomic force microscopy, respectively. In addition, in order to investigate the optical properties of the thin films, the UV-visible spectrophotometry was used. The XRD results indicated that the deposited MnS2 thin films exhibited a polycrystalline cubic structure. The number of MnS2 peaks on the XRD patterns initially increased from three to six peaks and then decreased to five peaks, as the deposition time was increased from 2 to 8 days. From the AFM measurements, the film thickness and surface roughness were found to be dependent on the deposition time.

Flow cytometric estimation on cytotoxic activity of leaf extracts from seashore plants in subtropical Japan: isolation, quantification and cytotoxic action of (-)-deoxypodophyllotoxin.

Science.gov (United States)

Masuda, Toshiya; Oyama, Yasuo; Yonemori, Shigetomo; Takeda, Yoshio; Yamazaki, Yuko; Mizuguchi, Shinichi; Nakata, Mami; Tanaka, Tomochika; Chikahisa, Lumi; Inaba, Yuzuru; Okada, Yoshihiko

2002-06-01

The cytotoxic activity of methanol extracts of leaves collected from 39 seashore plants in Iriomote Island, subtropical Japan was examined on human leukaemia cells (K562 cells) using a flow cytometer with two fluorescent probes, ethidium bromide and annexin V-FITC. Five extracts (10 microg/mL) from Hernandia nymphaeaefolia, Cerbera manghas, Pongamia pinnata, Morus australis var. glabra and Thespesia populnea greatly inhibited the growth of K562 cells. When the concentration was decreased to 1 microg/mL, only one extract from H. nymphaeaefolia still inhibited the cell growth. A cytotoxic compound was isolated from the leaves by bioassay-guided fractionation and was identified as (-)-deoxypodophyllotoxin (DPT). The fresh leaves of H. nymphaeaefolia contained a remarkably high amount of DPT (0.21 +/- 0.07% of fresh leaf weight), being clarified by a quantitative HPLC analysis. DPT at 70-80 pM started to inhibit the growth of K562 cells in an all-or-none fashion and at 100 pM or more it produced complete inhibition in all cases. Therefore, the slope of the dose-response curve was very steep. DPT at 100 pM or more decreased the cell viability to 50%-60% and increased the number of cells undergoing apoptosis (annexin V-positive cells). The results indicate that DPT contributes to the cytotoxic action of the extract from the leaves of H. nymphaeaefolia on K562 cells. Copyright 2002 John Wiley & Sons, Ltd.

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)

Alternative method of portable irradiation of manganese sulphate solution by an plutonium-beryllium source for manganese sulphate bath efficiency measurements

International Nuclear Information System (INIS)

Silva, Fellipe Souza da; Martins, Marcelo Marques; Pereira, Walsan Wagner

2016-01-01

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_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)

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.

Identifying non-toxic doses of manganese for manganese-enhanced magnetic resonance imaging to map brain areas activated by operant behavior in trained rats.

Science.gov (United States)

Gálosi, Rita; Szalay, Csaba; Aradi, Mihály; Perlaki, Gábor; Pál, József; Steier, Roy; Lénárd, László; Karádi, Zoltán

2017-04-01

Manganese-enhanced magnetic resonance imaging (MEMRI) offers unique advantages such as studying brain activation in freely moving rats, but its usefulness has not been previously evaluated during operant behavior training. Manganese in a form of MnCl 2 , at a dose of 20mg/kg, was intraperitoneally infused. The administration was repeated and separated by 24h to reach the dose of 40mg/kg or 60mg/kg, respectively. Hepatotoxicity of the MnCl 2 was evaluated by determining serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, albumin and protein levels. Neurological examination was also carried out. The animals were tested in visual cue discriminated operant task. Imaging was performed using a 3T clinical MR scanner. T1 values were determined before and after MnCl 2 administrations. Manganese-enhanced images of each animal were subtracted from their baseline images to calculate decrease in the T1 value (ΔT1) voxel by voxel. The subtracted T1 maps of trained animals performing visual cue discriminated operant task, and those of naive rats were compared. The dose of 60mg/kg MnCl 2 showed hepatotoxic effect, but even these animals did not exhibit neurological symptoms. The dose of 20 and 40mg/kg MnCl 2 increased the number of omissions and did not affect the accuracy of performing the visual cue discriminated operant task. Using the accumulated dose of 40mg/kg, voxels with a significant enhanced ΔT1 value were detected in the following brain areas of the visual cue discriminated operant behavior performed animals compared to those in the controls: the visual, somatosensory, motor and premotor cortices, the insula, cingulate, ectorhinal, entorhinal, perirhinal and piriform cortices, hippocampus, amygdala with amygdalohippocampal areas, dorsal striatum, nucleus accumbens core, substantia nigra, and retrorubral field. In conclusion, the MEMRI proved to be a reliable method to accomplish brain activity mapping in correlation with the operant behavior

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...

Analogues of luteinizing hormone-releasing hormone containing cytotoxic groups.

Science.gov (United States)

Janáky, T; Juhász, A; Bajusz, S; Csernus, V; Srkalovic, G; Bokser, L; Milovanovic, S; Redding, T W; Rékási, Z; Nagy, A

1992-02-01

In an attempt to produce better cytotoxic analogues, chemotherapeutic antineoplastic radicals including an alkylating nitrogen mustard derivative of D-phenylalanine (D-melphalan), reactive cyclopropane, anthraquinone derivatives [2-(hydroxymethyl)anthraquinone and the anticancer antibiotic doxorubicin], and an antimetabolite (methotrexate) were coupled to suitably modified agonists and antagonists of luteinizing hormone-releasing hormone (LH-RH). Analogues with D-lysine6 and D-ornithine6 or N epsilon-(2,3-diaminopropionyl)-D-lysine and N delta-(2,3-diaminopropionyl)-D-ornithine were used as carriers for one or two cytotoxic moieties. The enhanced biological activities produced by the incorporation of D amino acids into position 6 of the agonistic analogues were further increased by the attachment of hydrophobic cytotoxic groups, resulting in compounds with 10-50 times higher activity than LH-RH. Most of the monosubstituted agonistic analogues showed high affinities for the membrane receptors of human breast cancer cells, while the receptor binding affinities of peptides containing two cytotoxic side chains were lower. Antagonistic carriers [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Trp3,Arg5,D-Lys6,D-Ala10] LH-RH [where Nal(2) is 3-(2-naphthyl)alanine], [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Trp3,Arg5,N epsilon-(2,3-diaminopropionyl)-D-Lys6,D-Ala10]LH-RH, and their D-Pal(3)3 homologs [Pal(3) is 3-(3-pyridyl)alanine] as well as [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Pal(3)3,Tyr5,N epsilon-(2,3-diamino-propionyl)-D-Lys6,D-Ala10]LH-RH were linked to cytotoxic compounds. The hybrid molecules inhibited ovulation in rats at doses of 10 micrograms and suppressed LH release in vitro. The receptor binding of cytotoxic analogues was decreased compared to the precursor peptides, although analogues with 2-(hydroxymethyl)anthraquinone hemiglutarate had high affinities. All of the cytotoxic analogues tested inhibited [3H]thymidine incorporation into DNA in cultures of human breast and prostate cancer cell lines

Effects of Cytochrome P 450 Inhibitors on Itraconazole and Fluconazole Induced Cytotoxicity in Hepatocytes

International Nuclear Information System (INIS)

Somchit, N.; Ngee, C.S.; Yaakob, A.; Ahmad, Z.; Zakaria, Z.A.

2009-01-01

Itraconazole and fluconazole have been reported to induce hepatotoxicity in patients. The present study was designed to investigate the role of cytochrome P450 inhibitors, SKF 525A, and curcumin pretreatment on the cytotoxicity of antifungal drugs fluconazole and itraconazole. For 3 consecutive days, female rats were administered daily SKF 525A or curcumin (5 and 25?mg/kg). Control rats received an equivalent amount of dosed vehicle. The animals were anaesthetised 24 hours after receiving the last dose for liver perfusion. Hepatocytes were then exposed to various concentrations of antifungal drugs. In vitro incubation of hepatocytes with itraconazole revealed significantly lower viability when compared to fluconazole as assessed by lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase activities. The cytotoxicity of itraconazole was enhanced when incubated with hepatocytes pretreated with SKF 525A. SKF 525A had no effects on the cytotoxicity of fluconazole. Curcumin failed to either increase or decrease the cytotoxicity of both antifungal drugs. ATP levels also showed significant decrease in both itraconazole and fluconazole incubated hepatocytes. However, SKF 525A pretreated hepatocytes had significantly lower ATP levels after itraconazole incubations. Collectively, these results confirm the involvement of cytochrome P450 in the cytoprotection in itraconazole induced hepatocyte toxicity. Differences of the effects of SKF 525A on the cytotoxicity induced by itraconazole and fluconazole may be due to the differences on the metabolism of each antifungal drug in vivo.

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

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.

Effect of Hfe Deficiency on Memory Capacity and Motor Coordination after Manganese Exposure by Drinking Water in Mice.

Science.gov (United States)

Alsulimani, Helal Hussain; Ye, Qi; Kim, Jonghan

2015-12-01

Excess manganese (Mn) is neurotoxic. Increased manganese stores in the brain are associated with a number of behavioral problems, including motor dysfunction, memory loss and psychiatric disorders. We previously showed that the transport and neurotoxicity of manganese after intranasal instillation of the metal are altered in Hfe-deficient mice, a mouse model of the iron overload disorder hereditary hemochromatosis (HH). However, it is not fully understood whether loss of Hfe function modifies Mn neurotoxicity after ingestion. To investigate the role of Hfe in oral Mn toxicity, we exposed Hfe-knockout (Hfe (-/-)) and their control wild-type (Hfe (+/+)) mice to MnCl2 in drinking water (5 mg/mL) for 5 weeks. Motor coordination and spatial memory capacity were determined by the rotarod test and the Barnes maze test, respectively. Brain and liver metal levels were analyzed by inductively coupled plasma mass spectrometry. Compared with the water-drinking group, mice drinking Mn significantly increased Mn concentrations in the liver and brain of both genotypes. Mn exposure decreased iron levels in the liver, but not in the brain. Neither Mn nor Hfe deficiency altered tissue concentrations of copper or zinc. The rotarod test showed that Mn exposure decreased motor skills in Hfe (+/+) mice, but not in Hfe (-/-) mice (p = 0.023). In the Barns maze test, latency to find the target hole was not altered in Mn-exposed Hfe (+/+) compared with water-drinking Hfe (+/+) mice. However, Mn-exposed Hfe (-/-) mice spent more time to find the target hole than Mn-drinking Hfe (+/+) mice (p = 0.028). These data indicate that loss of Hfe function impairs spatial memory upon Mn exposure in drinking water. Our results suggest that individuals with hemochromatosis could be more vulnerable to memory deficits induced by Mn ingestion from our environment. The pathophysiological role of HFE in manganese neurotoxicity should be carefully examined in patients with HFE-associated hemochromatosis and

Effect of radiotherapy on lymphocyte cytotoxicity against allogeneic lung cancer cells in patients with bronchogenic carcinoma

International Nuclear Information System (INIS)

Toyohira, Ken; Yasumoto, Kosei; Manabe, Hideo; Ohta, Mitsuo; Terashima, Hiromi

1979-01-01

Cytotoxicity of peripheral blood lymphocytes against allogeneic target cells of bronchogenic carcinoma was examined by a microcytotoxicity test before, during, and after radiotherapy in primary lung cancer patients. Before the treatment, cytotoxicity was depressed only slightly in patients in stage III and strikingly in those in stage IV, as compared to the values in patients at earlier stages of lung cancer such as stages I and II. Local irradiation scarcely affected cytotoxicity at stages II and III, but augmented remarkably at stage IV. The number of peripheral blood lymphocytes decreased profoundly during and after radiotherapy in all cases of stages II, III, and IV. Although radiotherapy exhibited various effects on the cytotoxic activity of lymphocytes and the number of peripheral blood lymphocytes, only the cytotoxic activity at the end of radiotherapy correlated well with the reduction in tumor size. (author)

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....

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

Structure-cytotoxicity relationships for dietary flavonoids

DEFF Research Database (Denmark)

Breinholt, V.; Dragsted, L.O.

1998-01-01

The cytotoxicity of a large series of dietary flavonoids was tested in a non-tumorigenic mouse and two human cancer cell lines, using the neutral red dye exclusion assay. All compounds tested exhibited a concentration-dependent cytotoxic action in the employed cell lines. The relative cytotoxicity...... of the flavonoids, however, Tvas found to vary greatly among the different cell Lines. With a few exceptions, the investigated flavonoids were more cytotoxic to the human cancer cell lines, than the mouse cell line. The differences in cytotoxicity were accounted for in part by differences in cellular uptake...... and metabolic capacity among the different cell types. In 3T3 cells fairly consistent structure-cytotoxicity relationships were found. The most cytotoxic structures tested in 3T3 cells were flavonoids with adjacent 3',4' hydroxy groups on the B-ring, such as luteolin, quercetin, myricetin, fisetin, eriodictyol...

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.

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)

Cytotoxicity of Light-Cured Dental Materials according to Different Sample Preparation Methods

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Myung-Jin Lee

2017-03-01

Full Text Available Dental light-cured resins can undergo different degrees of polymerization when applied in vivo. When polymerization is incomplete, toxic monomers may be released into the oral cavity. The present study assessed the cytotoxicity of different materials, using sample preparation methods that mirror clinical conditions. Composite and bonding resins were used and divided into four groups according to sample preparation method: uncured; directly cured samples, which were cured after being placed on solidified agar; post-cured samples were polymerized before being placed on agar; and “removed unreacted layer” samples had their oxygen-inhibition layer removed after polymerization. Cytotoxicity was evaluated using an agar diffusion test, MTT assay, and confocal microscopy. Uncured samples were the most cytotoxic, while removed unreacted layer samples were the least cytotoxic (p < 0.05. In the MTT assay, cell viability increased significantly in every group as the concentration of the extracts decreased (p < 0.05. Extracts from post-cured and removed unreacted layer samples of bonding resin were less toxic than post-cured and removed unreacted layer samples of composite resin. Removal of the oxygen-inhibition layer resulted in the lowest cytotoxicity. Clinicians should remove unreacted monomers on the resin surface immediately after restoring teeth with light-curing resin to improve the restoration biocompatibility.

A flow-cytometric NK-cytotoxicity assay adapted for use in rat repeated dose toxicity studies

International Nuclear Information System (INIS)

Marcusson-Staahl, Maritha; Cederbrant, Karin

2003-01-01

A recent regulatory document for immunotoxicity testing of new pharmaceutical drugs includes cytotoxic natural killer (NK)-cell function as a required parameter in repeated dose toxicity studies. The classical 51 Cr-release assay is the conventional test for cytotoxicity testing but several drawbacks with this assay has increased the demand for new reliable test systems. Here, we describe the optimisation of a flow-cytometric cytotoxicity assay especially adapted for regulatory rat studies in drug development. The test principle is based on target cell labelling with 5-(6)-carboxy-fluorescein succinimidyl ester (CFSE) and subsequent DNA-labelling with propidium iodide (PI) for identification of target cells with compromised cell membranes. The results are expressed as percentage of dead targets on a cell-to-cell basis. The final format of the assay includes 0.5 ml peripheral blood, 1.25x10 5 effector cells per sample, and collection of 500 target events by flow-cytometry. When NKR-P1+ cells were removed from the effector cell population by magnetic depletion the relative proportion decreased from 6 to 0.08%. The corresponding cytotoxic activity decreased from 68 to 8%. Also, the cytotoxic activity showed a significant and positive correlation with the proportion of NK-cells present in the effector cell suspension. Thus, the cytotoxicity measured is almost exclusively exerted by NK-cells. The current flow-cytometric test benefits from using peripheral blood as a source for effector cells since it will not conflict with the use of spleen for histopathological investigations in repeated dose toxicity studies. Additionally, since only a minimal number of effector cells are required per sample repeated testing of the same animal is enabled

Oxidative Precipitation of Manganese from Acid Mine Drainage by Potassium Permanganate

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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.

Decontamination of irradiated-fuel processing waste using manganese dioxide hydrate

International Nuclear Information System (INIS)

Auchapt, J.M.; Gaudier, J.F.

1969-01-01

The 'manganese dioxide' process is designed to replace the 'calcium carbonate' treatment for low and medium activity wastes. The objective to attain during the research for a new process was the diminution of the volume of the sludge without decreasing the decontamination factor of the wastes. The new process involves addition in series of twice over 100 ppm of Mn 2+ in the waste which has previously been made basic and oxidizing; the precipitate formed in situ is separated after each addition. The process has the advantage of increasing the decontamination of strontium. The treatment can be used in a plant including two decantation units and has given effective results when applied in such a plant. (author) [fr

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

Box-Behnken Design Application to Study Leaching of Pyrolusite from Manganese Mining Residue Using Olive Mill Wastewater as Reductant

Science.gov (United States)

Alaoui, Abdallah; El Kacemi, K.; El Ass, K.; Kitane, S.; El Bouzidi, S.

2015-05-01

The leaching capacity of olive mill wastewater (OMW) for pyrolusite mine tailings (MnO2) was evaluated using the Box-Behnken experimental design of response surface methodology. The selected test parameters include the concentration of sulfuric acid, the OMW dosage chemical oxygen demand (COD), the solid/liquid ratio S/ L, and particle size. It was determined that the MnO2 dissolution increased with an increase in the sulfuric acid concentration and the OMW dosage, and with a decrease in the solid/liquid ratio. The particle size does not have significant influence on the manganese recovery. A quadratic polynomial model has been developed to predict the amount of manganese extraction from pyrolusite for other operating conditions that were not directly tested. The leaching ability was evaluated based on manganese recovery (Mn%) and the removal capability of chemical oxygen demand (COD%). The predicted values for the responses agreed well with experimental values; R 2 (correlation coefficient) values for Mn% and COD% were 0.9602 and 0.9687, respectively. Within the design space, the optimum conditions for the lixiviation of MnO2 in terms of manganese recovery and COD removal were established and include [H2SO4] of 3 mol L-1, OMW in range of 23 g L-1 to 25 g L-1 COD, and pulp density in range of 90 g L-1 to 100 g L-1. Under these conditions, the response values generated by the model are Mn% ˜49% and COD% >40%. These values show good agreement with those obtained in the validation test. This study has demonstrated that it is possible to use the olive mill wastewater as a reductant agent to recover manganese from a pyrolusite mining residue.

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

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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

Development of low-cost technology for the removal of iron and manganese from ground water in siwa oasis.

Science.gov (United States)

El-Naggar, Hesham M

2010-01-01

Ground water is the only water resource for Siwa Oasis. It is obtained from natural freshwater wells and springs fed by the Nubian aquifer. Water samples collected from Siwa Oasis had relatively higher iron (Fe) and manganese (Mn) than the permissible limits specified in WHO Guidelines and Egyptian Standards for drinking water quality. Aeration followed by sand filtration is the most commonly used method for the removal of iron from ground water. The study aimed at development of low-cost technology for the removal of iron and manganese from ground water in Siwa Oasis. The study was carried out on Laboratory-scale columns experiments sand filters with variable depths of 15, 30, 45, 60, 75, 90 cm and three graded types of sand were studied. The graded sand (E.S. =0.205 mm, U.C. =3.366, depth of sand = 60 cm and filtration rate = 1.44 m3/m2/hr) was the best type of filter media. Iron and manganese concentrations measured in ground water with aeration only, decreased with an average removal percentage of 16%, 13% respectively. Iron and manganese concentrations after filtration with aeration came down to 0.1123, 0.05 mg/L respectively in all cases from an initial concentration of 1.14, 0.34 mg/L respectively. Advantages of such treatment unit included simplicity, low cost design, and no need for chemical addition. In addition, the only maintenance required was periodic washing of the sand filter or replacement of the sand in order to maintain reasonable flow rate through the system.

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.

Misonidazole cytotoxicity in vivo: a comparison of large single doses with smaller doses and extended contact of the drug with tumor cells

International Nuclear Information System (INIS)

Conroy, P.J.; Sutherland, R.M.; Passalacqua, W.

1980-01-01

Experiments were performed to determine the kinetics and magnitude of misonidazole cytotoxicity in EMT6/Ro tumors using an in vivo-in vitro clonogenicity assay. A comparison was made between the cytotoxic effects of large single doses with smaller doses of misonidazole administered ip and those produced on extended contact of the drug with tumor cells using a continuous iv drug infusion system. After a single ip dose of 1 mg/g, cytotoxicity was maximum at 18 to 24 h; by 72 h the clonogenic cells per tumor had returned to control levels. The maximum cytotoxicity was greater (a decrease of 10 times) if the animals were kept at 37 0 C compared with ambient conditions (a decrease of 4.5 times) where the body temperature would decrease due to the drug. A dose-response curve performed with the animals at 37 0 C showed no significant cytotoxicity at 18 h after single ip doses of 0.5 mg/g or less. Other experiments were carried out at 37 0 C using a drug continuous infusion system. Two profiles were studied: (a) continuous constant rate infusion over 3 days of constant serum and tumor levels of both 100 and 200 μg/ml and (b) continuous variable rate infusion where the maximum serum levels reached 80 or 200 μg/ml after 2 to 4 h and decayed with a half-life of 12 h as in humans. Significant cytotoxicity was obtained under both of these conditions. Maximum cytotoxicity occurred at about 24 h in both types of experiments and amounted to decreases of clonogenic tumor cells of 4.5 and 7 times for 100 and 200 μg/ml, respectively, after constant rate infusion and 2 to 4 times for 80 and 200 μg/ml, respectively, after variable rate infusion. Because of the relatively rapid recovery in the number of clonogenic tumor cells by 72 h, the cytotoxic effects were not reflected as changes in tumor size even when the animals were maintained at 37 0 C

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.

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)

Artifacts by marker enzyme adsorption on nanomaterials in cytotoxicity assays with tissue cultures

International Nuclear Information System (INIS)

Wohlleben, Wendel; Kolle, Susanne N; Hasenkamp, Laura-Carolin; Boeser, Alexander; Vogel, Sandra; Vacano, Bernhard von; Ravenzwaay, Ben van; Landsiedel, Robert

2011-01-01

We used precision cut lung slices (PCLS) to study the cytotoxicity of cobalt ferrite nanomaterials with and without bovine serum albumin (BSA) stabilization. Using mitochondrial activity as an indicator of cytotoxicity (WST-1 assay) increasing concentrations of cobalt ferrite nanomaterial caused increasing levels of cytotoxicity in PCLS irrespective of BSA stabilization. However, there was no increase in released lactate dehydrogenase (LDH) levels caused by BSA stabilized nanomaterial indicating concentration depended cytotoxictiy. Moreover, non-stabilized nanomaterial caused a decrease of background LDH levels in the PCLS culture supernatant confirmed by complementary methods. Direct characterization of the protein corona of extracted nanomaterial shows that the LDH decrease is due to adsorption of LDH onto the surface of the non-stabilized nanomaterial, correlated with strong agglomeration. Preincubation with serum protein blocks the adsorption of LDH and stabilizes the nanomaterial at low agglomeration. We have thus demonstrated the cytotoxicity of nanomaterials in PCLS does not correlate with disrupted membrane integrity followed by LDH release. Furthermore, we found that intracellular enzymes such as the marker enzyme LDH are able to bind onto surfaces of nanomaterial and thereby adulterate the detection of toxic effects. A replacement of BSA by LDH or a secondary LDH-on-BSA-corona were not observed, confirming earlier indications that the protein corona exchange rate are slow or vanishing on inorganic nanomaterial. Thus, the method(s) to assess nanomaterial-mediated effects have to be carefully chosen based on the cellular effect and possible nano-specific artifacts.

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.

Effect of carbon and manganese on the microstructure and mechanical properties of 9Cr2WVTa deposited metals

Energy Technology Data Exchange (ETDEWEB)

Wang, Jian [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China); Rong, Lijian [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China); Li, Dianzhong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China); Lu, Shanping, E-mail: shplu@imr.ac.cn [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China)

2017-03-15

Six 9Cr2WVTa deposited metals with different carbon and manganese contents have been studied to reveal the role of major elements, which guide for the design of welding consumables for reduced activation ferritic/martensitic steel and meet for the requirements of accelerator driven systems-lead fusion reactors. The typical microstructure for the 9Cr2WVTa deposited metals is the lath martensite along with the fine stripe δ-ferrite. The chemical compositions influence the solidification sequence and therefore, change the δ-ferrite content in the deposited metal. The impact toughness for the 9Cr2WVTa deposited metals decreases remarkably when the δ-ferrite content is more than 5.2 vol%, also the impact toughness decreases owing to the high quenching martensite formation. Increasing the level of manganese addition, α phase of each alloy shifts to the bottom right according to the CCT diagram. - Highlights: • The typical deposited metals is the lath martensite with the fine stripe δ-ferrite. • The impact toughness is dependent on the δ-ferrite and the high quenching martensite. • The chemical compositions influence the solidification sequence.

Flavonoids of Calligonum polygonoides and their cytotoxicity.

Science.gov (United States)

Ahmed, Hayam; Moawad, Abeer; Owis, Asmaa; AbouZid, Sameh; Ahmed, Osama

2016-10-01

Context Calligonum polygonoides L. subsp. comosum L' Hér. (Polygonaceae), locally known as "arta", is a slow-growing small leafless desert shrub. Objective Isolation, structure elucidation and evaluation of cytotoxic activity of flavonoids from C. polygonoides aerial parts. Materials and methods Flavonoids in the hydroalcoholic extract of the of C. polygonoides were isolated and purified using column chromatography and preparative HPLC. The structures of the isolated flavonoids were elucidated on the basis of spectroscopic data including 2D NMR techniques. The cytotoxic activity of the isolated flavonoids (6.25, 25, 50 and 100 μg/mL) was evaluated against liver HepG2 and breast MCF-7 cancer cell lines using sulphorhodamine-B assay. Results A new flavonoid, kaempferol-3-O-β-D-(6″-n-butyl glucuronide) (1), and 13 known flavonoids, quercetin 3-O-β-D-(6″-n-butyl glucuronide) (2), kaempferol-3-O-β-D-(6″-methyl glucuronide) (3), quercetin-3-O-β-D-(6″-methyl glucuronide) (4), quercetin-3-O-glucuronide (5), kaempferol-3-O-glucuronide (6), quercetin-3-O-α-rhamnopyranoside (7), astragalin (8), quercetin-3-O-glucopyranoside (9), taxifolin (10), (+)-catechin (11), dehydrodicatechin A (12), quercetin (13), and kaempferol (14), were isolated from the aerial parts of C. polygonoides. Quercetin showed significant cytotoxic activity against HepG2 and MCF-7 cell lines with IC50 values of 4.88 and 0.87 μg/mL, respectively. Structure-activity relationships were analyzed by comparing IC50 values of several pairs of flavonoids differing in one structural element. Discussion and conclusion The activity against breast cancer cell lines decreased by glycosylation at C-3. The presence of 2,3-double bond in ring C, carbonyl group at C-4 and 3',4'-dihydroxy substituents in ring B are essential structural requirements for the cytotoxic activity against breast cancer cells.

Decontamination of irradiated-fuel processing waste using manganese dioxide hydrate; Decontamination des effluents de traitement des combustibles irradies par le bioxyde de manganese hydrate

Energy Technology Data Exchange (ETDEWEB)

Auchapt, J M; Gaudier, J F [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

1969-07-01

The 'manganese dioxide' process is designed to replace the 'calcium carbonate' treatment for low and medium activity wastes. The objective to attain during the research for a new process was the diminution of the volume of the sludge without decreasing the decontamination factor of the wastes. The new process involves addition in series of twice over 100 ppm of Mn{sup 2+} in the waste which has previously been made basic and oxidizing; the precipitate formed in situ is separated after each addition. The process has the advantage of increasing the decontamination of strontium. The treatment can be used in a plant including two decantation units and has given effective results when applied in such a plant. (author) [French] Le procede au ''bioxyde de manganese'' est destine a remplacer le traitement ''carbonate de calcium'' dans les effluents de moyenne activite. L'objectif poursuivi lors de la recherche d'un procede nouveau etait de diminuer le volume des boues sans diminuer le facteur de decontamination des effluents. Le nouveau traitement consiste a effectuer en cascade sur les effluents rendus basiques et oxydants une double precipitation de 100 ppm de Mn{sup 2+} avec separation intermediaire du precipite. Il presente en outre l'avantage d'ameliorer la decontamination en strontium. Le traitement est utilisable dans la chaine des deux decanteurs et a donne satisfaction lors de son exploitation industrielle. Le volume des boues seches a ete reduit d'un facteur 3 a 4 par rapport au traitement carbonate. (auteur)

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.

Cytotoxic effect of ciprofloxacin in primary culture of rat astrocytes and protection by Vitamin E

International Nuclear Information System (INIS)

Guerbay, Aylin; Gonthier, Brigitte; Barret, Luc; Favier, Alain; Hincal, Filiz

2007-01-01

The aim of this study was to investigate the possible cytotoxic and oxidative stress inducing effects of ciprofloxacin (CPFX) on primary cultures of rat astrocytes. The cultured cells were incubated with various concentrations of CPFX (0.5-300 mg/l), and cytotoxicity was determined by neutral red (NR) and MTT assays. Survival profile of cells was biphasic in NR assay: CPFX did not cause any alteration at any concentration for 7 h, whereas ≤50 mg/l concentrations induced significant cell proliferation in incubation periods of 24, 48, 72, and 96 h. However, cell proliferation gradually decreased at higher concentrations, and 200 and 300 mg/l of CPFX exposure was found to be significantly (p < 0.05) cytotoxic at all time periods. With MTT assay, no alteration was noted for incubation period of 7 h, as observed with NR assay. But, cell viability decreased with ∼≥50 mg/l CPFX exposure in all other time periods. Cell proliferation was only seen in 24 h of incubation with 0.5 and 5 mg/l CPFX. Vitamin E pretreatment of cell cultures were found to be providing complete protection against cytotoxicity of 300 mg/l CPFX in 96 h incubation when measured with both NR and MTT assays. The SOD pretreatment was partially protective with NR assay, but no protection was noted when measured with MTT. A significant enhancement of lipid peroxidation was observed with the cytotoxic concentration of the drug, but total glutathione content and catalase activity of cells did not change. The data obtained in this study suggest that, in accordance with our previous results with fibroblast cells, CPFX-induced cytotoxicity is related to oxidative stress. And the biphasic effect of CPFX possibly resulted from the complex dose-dependent relationships between reactive oxygen species, cell proliferation, and cell viability

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

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.

Efficiency of manganese dioxide for the removal of antimony from aqueous solutions

International Nuclear Information System (INIS)

Hasany, S.M.; Najamuddin; Ikram, M.

1993-01-01

The sorption of antimony onto manganese dioxide from aqueous solution has been investigated as a function of shaking time, composition of electrolyte, concentration of sorbent and sorbate, Maximum sorption of antimony has been achieved from deionized water after 15 minutes shaking at 45 cm/sup 3/g/sup -1/ V/W ratio. The influence of different anions and cations on the sorption has also been examined. EDTA, tartrate, citrate and Fe(II) decreased the sorption significantly. Among the metal ions tested only Se (IV) has shown strong sorption than antimony whereas Co(II), Hf (IV) and Te(IV) indicated low sorption affinity under similar experimental conditions. The sorption of antimony was also tested by different isotherms. The data fitted only to Freyndlich and D-R models. The sorption capacity of 7.71 m mole g/sup -1/, mean energy of sorption of 8.9 kJ mole/sup -1/ and of B = 0.00632 mole/sup 2/kJ/sup -2/ have been system. It is concluded that manganese dioxide can be used for the removal of antimony from industrial effluents and for its recovery from very dilute solutions. The oxide can also be applied for the separation of antimony, selenium and arsenic from Te(IV). (author)

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

In vitro anticancer activity and cytotoxicity of some papaver alkaloids ...

African Journals Online (AJOL)

Materials and Methods: The Vero and HeLa cell lines were treated with various concentrations (1-300 μg/mL) of alkaloids for 48 h. Values for cytotoxicity measured by MTT assay were expressed as the concentration that causes a 50% decrease in cell viability (IC50) (μg/mL). Results: Berberine and macranthine were the ...

Oxidative Mechanisms of Monocyte-Mediated Cytotoxicity

Science.gov (United States)

Weiss, Stephen J.; Lobuglio, Albert F.; Kessler, Howard B.

1980-01-01

Human monocytes stimulated with phorbol myristate acetate were able to rapidly destroy autologous erythrocyte targets. Monocyte-mediated cytotoxicity was related to phorbol myristate acetate concentration and monocyte number. Purified preparations of lymphocytes were incapable of mediating erythrocyte lysis in this system. The ability of phorbol myristate acetate-stimulated monocytes to lyse erythrocyte targets was markedly impaired by catalase or superoxide dismutase but not by heat-inactivated enzymes or albumin. Despite a simultaneous requirement for superoxide anion and hydrogen peroxide in the cytotoxic event, a variety of hydroxyl radical and singlet oxygen scavengers did not effect cytolysis. However, tryptophan significantly inhibited cytotoxicity. The myeloperoxidase inhibitor cyanide enhanced erythrocyte destruction, whereas azide reduced it modestly. The inability of cyanide to reduce cytotoxicity coupled with the protective effect of superoxide dismutase suggests that cytotoxicity is independent of the classic myeloperoxidase system. We conclude that monocytes, stimulated with phorbol myristate acetate, generate superoxide anion and hydrogen peroxide, which together play an integral role in this cytotoxic mechanism.

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.

Pattern of CD4 T‑lymphocyte Values in Cancer Patients on Cytotoxic ...

African Journals Online (AJOL)

Background: Assessment of patients prior to cytotoxic chemotherapy usually includes absolute neutrophils count. Other cellular markers of susceptibility to infection as well as immunocompetence include the T Helper lymphocyte count. In cancer patients, decrease in these lymphocytes has been observed to be associated ...

Cytotoxic Properties of Three Isolated Coumarin-hemiterpene Ether Derivatives from Artemisia armeniaca Lam.

Science.gov (United States)

Mojarrab, Mahdi; Emami, Seyed Ahmad; Delazar, Abbas; Tayarani-Najaran, Zahra

2017-01-01

Considering multiple reports on cytotoxic activity of the Artemisia genus and its phytochemicals, in the current study A. armeniaca Lam. and the three components isolated from the plant were subjected to cytotoxic studies. Analytical fractionation of A. armeniaca aerial parts for the first time was directed to the isolation of 7-hydroxy-8-(4-hydroxy-3-methylbutoxy) comarin (armenin), 8-hydroxy-7-(4-hydroxy-3-methylbutoxy) comarin (isoarmenin) and deoxylacarol. Cytotoxicity assessed with alamalBlue® assay and apoptosis was detected by PI staining and western blot analysis of Bax and PARP proteins. Extracts and all compounds exhibited cytotoxic activity against apoptosis-proficient HL-60 and apoptosis-resistant K562 cells, with the lowest cytotoxic activity on J774 cell line as non-malignant cell. Armenin as the most potent component decreased the viability of cell with IC50 of 22.5 and 71.1 µM for K562 and HL-60 cells respectively and selected for further mechanistic study. Armenin increased the sub-G1 peak in flow cytometry histogram of HL-60 and K562 treated cells and increase in the amount of Bax protein and the cleavage of PARP in comparison with the control after treatment for 48 h in K562 treated cells verified the apoptotic activity of the armenin. Taken together, according to the finding of this study armenin was introduced as a novel cytotoxic compound with apoptotic activity, which is encouraging for further mechanistic and clinical studies.

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.

Effects of manganese on tyrosine hydroxylase (TH) activity and TH-phosphorylation in a dopaminergic neural cell line

International Nuclear Information System (INIS)

Zhang Danhui; Kanthasamy, Arthi; Anantharam, Vellareddy; Kanthasamy, Anumantha

2011-01-01

Manganese (Mn) exposure causes manganism, a neurological disorder similar to Parkinson's disease. However, the cellular mechanism by which Mn impairs the dopaminergic neurotransmitter system remains unclear. We previously demonstrated that caspase-3-dependent proteolytic activation of protein kinase C delta (PKCδ) plays a key role in Mn-induced apoptotic cell death in dopaminergic neurons. Recently, we showed that PKCδ negatively regulates tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine synthesis, by enhancing protein phosphatase-2A activity in dopaminergic neurons. Here, we report that Mn exposure can affect the enzymatic activity of TH, the rate-limiting enzyme in dopamine synthesis, by activating PKCδ-PP2A signaling pathway in a dopaminergic cell model. Low dose Mn (3-10 μM) exposure to differentiated mesencephalic dopaminergic neuronal cells for 3 h induced a significant increase in TH activity and phosphorylation of TH-Ser40. The PKCδ specific inhibitor rottlerin did not prevent Mn-induced TH activity or TH-Ser40 phosphorylation. On the contrary, chronic exposure to 0.1-1 μM Mn for 24 h induced a dose-dependent decrease in TH activity. Interestingly, chronic Mn treatment significantly increased PKCδ kinase activity and protein phosphatase 2A (PP2A) enzyme activity. Treatment with the PKCδ inhibitor rottlerin almost completely prevented chronic Mn-induced reduction in TH activity, as well as increased PP2A activity. Neither acute nor chronic Mn exposures induced any cytotoxic cell death or altered TH protein levels. Collectively, these results demonstrate that low dose Mn exposure impairs TH activity in dopaminergic cells through activation of PKCδ and PP2A activity.

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

Reducing ZnO nanoparticle cytotoxicity by surface modification.

Science.gov (United States)

Luo, Mingdeng; Shen, Cenchao; Feltis, Bryce N; Martin, Lisandra L; Hughes, Anthony E; Wright, Paul F A; Turney, Terence W

2014-06-07

Nanoparticulate zinc oxide (ZnO) is one of the most widely used engineered nanomaterials and its toxicology has gained considerable recent attention. A key aspect for controlling biological interactions at the nanoscale is understanding the relevant nanoparticle surface chemistry. In this study, we have determined the disposition of ZnO nanoparticles within human immune cells by measurement of total Zn, as well as the proportions of extra- and intracellular dissolved Zn as a function of dose and surface coating. From this mass balance, the intracellular soluble Zn levels showed little difference in regard to dose above a certain minimal level or to different surface coatings. PEGylation of ZnO NPs reduced their cytotoxicity as a result of decreased cellular uptake arising from a minimal protein corona. We conclude that the key role of the surface properties of ZnO NPs in controlling cytotoxicity is to regulate cellular nanoparticle uptake rather than altering either intracellular or extracellular Zn dissolution.

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.

Cytotoxicity of Cerastes cerastes snake venom: Involvement of imbalanced redox status.

Science.gov (United States)

Kebir-Chelghoum, Hayet; Laraba-Djebari, Fatima

2017-09-01

Envenomation caused by Cerastes cerastes snake venom is characterized by a local and a systemic tissue damage due to myonecrosis, hemorrhage, edema and acute muscle damage. The present study aimed to evaluate the relationship between the pro/anti-oxidants status and the cytotoxicity of C. cerastes snake venom. The in vivo cytotoxicity analysis was undertaken by the injection of C. cerastes venom (48μg/20g body weight) by i.p. route, mice were then sacrificed at 3, 24 and 48h post injection, organs were collected for further analysis. In vitro cytotoxicity analysis was investigated on cultured PBMC, hepatocytes and isolated liver. The obtained results showed a significant cell infiltration characterized by a significant increase of myeloperoxidase (MPO) and eosinoperoxidase (EPO) activities. These results showed also a potent oxidative activity of C. cerastes venom characterized by increased levels of residual nitrites and lipid peroxidation associated with a significant decrease of glutathione and catalase activity in sera and tissues (heart, lungs, liver and kidneys). The in vitro cytotoxicity of C. cerastes venom on PBMC seems to be dose-dependent (IC50 of 21μg/ml/10 6 cells) and correlated with an imbalanced redox status at high doses of venom. However, in the case of cultured hepatocytes, the LDH release and oxidative stress were observed only at high doses of the venom. The obtained results of in vivo study were confirmed by the culture of isolated liver. Therefore, these results suggest that the venom induces a direct cytotoxic effect which alters the membrane integrity causing a leakage of the cellular contents. This cytotoxic effect can lead indirectly to inflammatory response and oxidative stress. These data suggest that an early anti-inflammatory and antioxidant treatment could be useful in the management of envenomed victims. Copyright © 2017. Published by Elsevier B.V.

Prevention of phosphine-induced cytotoxicity by nutrients in HepG2 cells

Directory of Open Access Journals (Sweden)

Marzieh Rashedinia

2016-01-01

Interpretation & conclusions: The results supported the hypothesis that phosphine-induced cytotoxicity was due to decrease of ATP levels. ATP suppliers could prevent its toxicity by generating ATP through glycolysis. α-keto compounds such as dihydroxyacetone and α-ketoglutarate may bind to phosphine and restore mitochondrial respiration.

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.

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

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

Cytotoxicity and inhibitory effects of low-concentration triclosan on adipogenic differentiation of human mesenchymal stem cells

Energy Technology Data Exchange (ETDEWEB)

Guo, Li-Wu [Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Wu, Qiangen [Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Green, Bridgett; Nolen, Greg [Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Shi, Leming [Division of Systems Biology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); LoSurdo, Jessica [Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 (United States); Deng, Helen [Arkansas Department of Health, Little Rock, AR 72205 (United States); Bauer, Steven [Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 (United States); Fang, Jia-Long, E-mail: jia-long.fang@fda.hhs.gov [Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Ning, Baitang, E-mail: baitang.ning@fda.hhs.gov [Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States)

2012-07-15

Humans at all ages are continually exposed to triclosan (TCS), a widely used antimicrobial agent that can be found in many daily hygiene products, such as toothpastes and shampoos; however, the toxicological and biological effects of TCS in the human body after long-term and low-concentration exposure are far from being well understood. In the current study, we investigated the effects of TCS on the differentiation of human mesenchymal stem cells (hMSCs) by measuring the cytotoxicity, morphological changes, lipid accumulation, and the expression of adipocyte differentiation biomarkers during 21-day adipogenesis. Significant cytotoxicity was observed in un-induced hMSCs treated with high-concentration TCS (≥ 5.0 μM TCS), but not with low-concentration treatments (≤ 2.5 μM TCS). TCS inhibited adipocyte differentiation of hMSCs in a concentration-dependent manner in the 0.156 to 2.5 μM range as indicated by morphological changes with Oil Red O staining, which is an index of lipid accumulation. The inhibitory effect was confirmed by a decrease in gene expression of specific adipocyte differentiation biomarkers including adipocyte protein 2, lipoprotein lipase, and adiponectin. Our study demonstrates that TCS inhibits adipocyte differentiation of hMSCs under concentrations that are not cytotoxic and in the range observed in human blood. -- Highlights: ► TCS is cytotoxic to un-induced hMSCs at concentrations ≥ 5.0 μM. ► TCS at concentrations ≤ 2.5 μM is not cytotoxic to induced hMSCs. ► TCS at non-cytotoxic concentrations inhibits lipid formation in induced hMSCs. ► TCS decreases the expression of specific biomarkers of adipocyte differentiation. ► TCS at concentrations observed in human blood inhibits adipogenesis of hMSCs.

Cytotoxicity and inhibitory effects of low-concentration triclosan on adipogenic differentiation of human mesenchymal stem cells

International Nuclear Information System (INIS)

Guo, Li-Wu; Wu, Qiangen; Green, Bridgett; Nolen, Greg; Shi, Leming; LoSurdo, Jessica; Deng, Helen; Bauer, Steven; Fang, Jia-Long; Ning, Baitang

2012-01-01

Humans at all ages are continually exposed to triclosan (TCS), a widely used antimicrobial agent that can be found in many daily hygiene products, such as toothpastes and shampoos; however, the toxicological and biological effects of TCS in the human body after long-term and low-concentration exposure are far from being well understood. In the current study, we investigated the effects of TCS on the differentiation of human mesenchymal stem cells (hMSCs) by measuring the cytotoxicity, morphological changes, lipid accumulation, and the expression of adipocyte differentiation biomarkers during 21-day adipogenesis. Significant cytotoxicity was observed in un-induced hMSCs treated with high-concentration TCS (≥ 5.0 μM TCS), but not with low-concentration treatments (≤ 2.5 μM TCS). TCS inhibited adipocyte differentiation of hMSCs in a concentration-dependent manner in the 0.156 to 2.5 μM range as indicated by morphological changes with Oil Red O staining, which is an index of lipid accumulation. The inhibitory effect was confirmed by a decrease in gene expression of specific adipocyte differentiation biomarkers including adipocyte protein 2, lipoprotein lipase, and adiponectin. Our study demonstrates that TCS inhibits adipocyte differentiation of hMSCs under concentrations that are not cytotoxic and in the range observed in human blood. -- Highlights: ► TCS is cytotoxic to un-induced hMSCs at concentrations ≥ 5.0 μM. ► TCS at concentrations ≤ 2.5 μM is not cytotoxic to induced hMSCs. ► TCS at non-cytotoxic concentrations inhibits lipid formation in induced hMSCs. ► TCS decreases the expression of specific biomarkers of adipocyte differentiation. ► TCS at concentrations observed in human blood inhibits adipogenesis of hMSCs.

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

In Vitro Cytotoxic Potential of Essential Oils of Eucalyptus benthamii and Its Related Terpenes on Tumor Cell Lines

Directory of Open Access Journals (Sweden)

Patrícia Mathias Döll-Boscardin

2012-01-01

Full Text Available Eucalyptus L. is traditionally used for many medicinal purposes. In particular, some Eucalyptus species have currently shown cytotoxic properties. Local Brazilian communities have used leaves of E. benthamii as a herbal remedy for various diseases, including cancer. Considering the lack of available data for supporting this cytotoxic effect, the goal of this paper was to study the in vitro cytotoxic potential of the essential oils from young and adult leaves of E. benthamii and some related terpenes (α-pinene, terpinen-4-ol, and γ-terpinene on Jurkat, J774A.1 and HeLa cells lines. Regarding the cytotoxic activity based on MTT assay, the essential oils showed improved results than α-pinene and γ-terpinene, particularly for Jurkat and HeLa cell lines. Terpinen-4-ol revealed a cytotoxic effect against Jurkat cells similar to that observed for volatile oils. The results of LDH activity indicated that cytotoxic activity of samples against Jurkat cells probably involved cell death by apoptosis. The decrease of cell DNA content was demonstrated due to inhibition of Jurkat cells proliferation by samples as a result of cytotoxicity. In general, the essential oils from young and adult leaves of E. benthamii presented cytotoxicity against the investigated tumor cell lines which confirms their antitumor potential.

In Vitro Cytotoxic Potential of Essential Oils of Eucalyptus benthamii and Its Related Terpenes on Tumor Cell Lines

Science.gov (United States)

Döll-Boscardin, Patrícia Mathias; Sartoratto, Adilson; Sales Maia, Beatriz Helena Lameiro de Noronha; Padilha de Paula, Josiane; Nakashima, Tomoe; Farago, Paulo Vitor; Kanunfre, Carla Cristine

2012-01-01

Eucalyptus L. is traditionally used for many medicinal purposes. In particular, some Eucalyptus species have currently shown cytotoxic properties. Local Brazilian communities have used leaves of E. benthamii as a herbal remedy for various diseases, including cancer. Considering the lack of available data for supporting this cytotoxic effect, the goal of this paper was to study the in vitro cytotoxic potential of the essential oils from young and adult leaves of E. benthamii and some related terpenes (α-pinene, terpinen-4-ol, and γ-terpinene) on Jurkat, J774A.1 and HeLa cells lines. Regarding the cytotoxic activity based on MTT assay, the essential oils showed improved results than α-pinene and γ-terpinene, particularly for Jurkat and HeLa cell lines. Terpinen-4-ol revealed a cytotoxic effect against Jurkat cells similar to that observed for volatile oils. The results of LDH activity indicated that cytotoxic activity of samples against Jurkat cells probably involved cell death by apoptosis. The decrease of cell DNA content was demonstrated due to inhibition of Jurkat cells proliferation by samples as a result of cytotoxicity. In general, the essential oils from young and adult leaves of E. benthamii presented cytotoxicity against the investigated tumor cell lines which confirms their antitumor potential. PMID:22645627

pH modulates transport rates of manganese and cadmium in the green alga Chlamydomonas reinhardtii through non-competitive interactions: Implications for an algal BLM

International Nuclear Information System (INIS)

Francois, Laura; Fortin, Claude; Campbell, Peter G.C.

2007-01-01

The influence of pH on short-term uptake of manganese and cadmium by the green alga Chlamydomonas reinhardtii was studied to better understand the nature of proton interactions with metal membrane transporters. Manganese and cadmium internalization fluxes (J int ) were measured over a wide range of free metal ion concentrations from 1 x 10 -10 to 4 x 10 -4 M at several pH values (Mn: 5.0, 6.5 and 8.0; Cd: 5.0 and 6.5). For both metals, first-order biological internalization kinetics were observed but the maximum transport flux (J max ) decreased when pH decreased, in contradiction with the Biotic Ligand Model (BLM). This result suggested a non-competitive inhibition of metal uptake by the H + -ion. A Michaelis-Menten type inhibition model considering proton and calcium competition was tested. The metal biotic ligand stability constants and the stability constants for competitive binding of Ca 2+ and H + with the metal transporters were calculated: for manganese, K Mn = 10 4.20 and K Ca = 10 3.71 ; for cadmium, K Cd = 10 4.19 and K Ca = 10 4.76 ; for both metal transport systems, K H was not a significant parameter. Furthermore, metal uptake was not significantly influenced by the pH of the antecedent growth medium, suggesting that increases in metal fluxes as the pH is raised are caused by conformational changes of the surface transport proteins rather than by the synthesis of additional transport sites. Our results demonstrate that the BLM in its present state does not properly describe the true influence of pH on manganese and cadmium uptake by algae and that a non-competitive inhibition component must be integrated

Cytotoxicity of Thirdhand Smoke and Identification of Acrolein as a Volatile Thirdhand Smoke Chemical That Inhibits Cell Proliferation.

Science.gov (United States)

Bahl, Vasundhra; Weng, Nikki J-H; Schick, Suzaynn F; Sleiman, Mohamad; Whitehead, Jacklyn; Ibarra, Allison; Talbot, Prue

2016-03-01

Thirdhand smoke (THS) is a mixture of chemicals that remain on indoor surfaces after smoking has ceased. These chemicals can be inhaled, ingested, or absorbed dermally, and thus could impact human health. We evaluated the cytotoxicity and mode of action of fresh and aged THS, the toxicity of volatile organic chemicals (VOCs) in THS, and the molecular targets of acrolein, a VOC in THS. Experiments were done using mouse neural stem cells (mNSC), human pulmonary fibroblasts (hPF), and lung A549 epithelial cells. THS-exposed cotton cloth was extracted in Dulbecco's Eagle Medium and caused cytotoxicity in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. THS extracts induced blebbing, immotility, vacuolization, cell fragmentation, severing of microfilaments and depolymerization of microtubules in mNSC. Cytotoxicity was inversely related to headspace volume in the extraction container and was lost upon aging, suggesting that VOCs in THS were cytotoxic. Phenol, 2',5'-dimethyl furan and acrolein were identified as the most cytotoxic VOCs in THS, and in combination, their cytotoxicity increased. Acrolein inhibited proliferation of mNSC and hPF and altered expression of cell cycle regulatory genes. Twenty-four hours of treatment with acrolein decreased expression of transcription factor Dp-1, a factor needed for the G1 to S transition in the cell cycle. At 48 h, WEE1 expression increased, while ANACP1 expression decreased consistent with blocking entry into and completion of the M phase of the cell cycle. This study identified acrolein as a highly cytotoxic VOC in THS which killed cells at high doses and inhibited cell proliferation at low doses. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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.

Colorimetric detection of manganese(II) ions using gold/dopa nanoparticles.

Science.gov (United States)

Narayanan, Kannan Badri; Park, Hyun Ho

2014-10-15

We report here a one-pot, greener, eco-friendly strategy for the synthesis of gold nanoparticles using L-dopa. The as-prepared dopa-functionalized gold nanoparticles (AuNPs/dopa) can detect low concentrations of manganese(II) metal ions in aqueous solution. The binding forces between dopa and Mn(2+) ions cause dopa-functionalized gold nanoparticles to come closer together, decreasing the interparticle distance and aggregating it with a change in color of colloidal solution from red to purplish-blue. Dynamic light scattering (DLS) analysis showed a decreased surface charge on the surface of gold nanoparticles when exposed to Mn(2+) ions, which caused cross-linking aggregation. Transmission electron microscopic (TEM) images also revealed the aggregation of gold nanoparticles with the addition of Mn(2+) ions. The extinction ratio of absorbance at 700-550nm (A700/A550) was linear against the concentration of [Mn(2+)] ions. Thus, the optical absorption spectra of gold colloidal solution before and after the addition of Mn(2+) ions reveal the concentration of Mn(2+) ions in solution. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitative analysis of manganese concentration in manganese-doped glasses by laser-induced breakdown spectroscopy using a nanosecond ultraviolet Nd:YAG laser

International Nuclear Information System (INIS)

Unnikrishnan, V.K.; Nayak, Rajesh; Kartha, V.B.; Santhosh, C.; Sonavane, M.S.; Yeotikar, R.G.; Gupta, G.P.; Suri, B.M.

2012-01-01

Laser-induced breakdown spectroscopy (LIBS) has been well recognized as a simple, fast and direct analytical technique for the analysis of elemental analysis of multi-element materials by a number of research groups all over the world. It is based on the focusing of a high-power pulsed laser beam with a power density > 100 MW/cm 2 onto a sample surface followed by optical emission spectroscopy of the plasma produced over the surface. During the last two decades, LIBS has attracted a lot of attention, leading to an ever increasing list of applications, both in laboratory and in industry. In this work, the quantitative analysis of manganese in manganese-doped glass samples in air at atmospheric pressure has been carried out by the LIBS system assembled and optimized in the laboratory. The plasma is generated using a nanosecond ultraviolet Nd:YAG laser with an irradiance of 1x10 9 W/cm 2 on the sample surface. The spatially integrated plasma light emission was collected and imaged on to the spectrograph slit using an optical-fibre-based collection system. An Echelle spectrograph-ICCD system (Andor Mechelle ME5000-DH734-18U-03PS150) was used to record the emission spectrum. The spectrograph with an Echelle grating covers 200-975 nm spectral range in a single shot with a good wavelength resolution (0.05 nm). The detector was gated in synchronization with the laser pulse to get maximum signal-to-background (S/B) ratio. The detector gate width of 2 μs and the detector gate delay of 2 μs were chosen for recording the plasma emission signals, discriminating the continuum radiation which is intense at initial delay time less than 300 ns and decreases at later time

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)

Cytotoxicity and genotoxicity of clothianidin in human lymphocytes with or without metabolic activation system.

Science.gov (United States)

Atlı Şekeroğlu, Zülal; Şekeroğlu, Vedat; Uçgun, Ebru; Kontaş Yedier, Seval; Aydın, Birsen

2018-02-26

Clothianidin (CHN) is a broad-spectrum neonicotinoid insecticide. Limited studies have been carried out on the cytotoxic and genotoxic effects of both CHN using different genotoxicity tests in human cells with or without human metabolic activation system (S9 mix). Therefore, the aim of this study is to investigate the cytotoxic and genotoxic effects of CHN and its metabolites on human lymphocyte cultures with or without S9 mix using chromosomal aberration (CA) and micronucleus (MN) tests. The cultures were treated with 25, 50, and 100 µg/ml of CHN in the presence (3 h treatment) and absence (48 h treatment) of S9 mix. Dimethyl sulfoxide (DMSO) was used as a solvent control. CHN showed cytotoxic and genotoxic effects due to significant decreases in mitotic index (MI) and nuclear division index (NDI), and significant increases in the CAs, aberrant cells, and MN formation in the absence of S9 mix when compared with solvent control. However, CHN did not significantly induce cytotoxicity and genotoxicity in the presence of S9 mix. Our results indicated that CHN has cytotoxic, cytostatic, and genotoxic potential on human peripheral blood lymphocyte cultures, but not its metabolites under the experimental conditions.

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

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

Manganese effects on haematopoietic cells and circulating coelomocytes of Asterias rubens (Linnaeus)

International Nuclear Information System (INIS)

Oweson, Carolina; Skoeld, Helen; Pinsino, Annalisa; Matranga, Valeria; Hernroth, Bodil

2008-01-01

Manganese (Mn) is a naturally abundant metal in marine sediments where it mainly occurs as MnO 2 . During hypoxic conditions it is converted into a bioavailable state, Mn 2+ , and can reach levels that previously have shown effects on immune competent cells of the crustacean, Nephrops norvegicus. Here we investigated if Mn also affects circulating coelomocytes and their renewal in the common sea star, Asterias rubens, when exposed to concentrations of Mn that can be found in nature. When the sea stars were exposed to Mn it accumulated in the coelomic fluid and the number of circulating coelomocytes, in contrast to what was recorded in Nephrops, increased significantly. By using the substitute nucleotide, 5-bromo-2'-deoxyuridine, BrdU, for tracing cell division and by recording mitotic index by nuclei staining, we found that Mn induced proliferation of cells from a putative haematopoietic tissue, the coelomic epithelium. In addition, the haematopoietic tissue and coelomocytes showed stress response in terms of changes in HSP70 levels and protein carbonyls, as judged by immunohistochemistry and Western blotting. Measurement of dehydrogenase activity, using MTS/PMS, revealed that Mn showed cytotoxic properties. We also found that the phagocytotic capacity of coelomocytes was significantly inhibited by Mn. It was concluded that the exposure of A. rubens to Mn induced renewal of coelomocytes and impaired their immune response

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.

Safety and effectiveness of scalp cooling in cancer patients undergoing cytotoxic treatment

NARCIS (Netherlands)

Hurk, Corina Johanna Geertruida van den

2013-01-01

Various cytotoxics cause severe alopecia, it is estimated to affect more than 15.000 Dutch cancer patients per year. Hair loss has high impact on the majority of these patients, they describe it as stigmatizing and a constant reminder of cancer disease. Scalp cooling decreases hair loss and is well

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...

Thermal stability of manganese-stabilized stainless steels

International Nuclear Information System (INIS)

Klueh, R.L.; Kenik, E.A.

1993-01-01

Previous work on a series of experimental high-manganese reduced-activation austenitic stainless steels demonstrated that they have improved tensile properties relative to type 316 stainless steel in both the annealed and 20% cold-worked conditions. Steels were tested with an Fe-20Mn-12Cr-0.25C (in weight percent) base composition, to which various combinations of Ti, W, V, P, and B were added. Tensile tests have now been completed on these steels after thermal aging at 600 degrees C. Thermal stability varied with composition, but the alloys were as stable or more stable than type 316 stainless steel. the strength of the annealed steels increased slightly after aging to 5000 h, while a strength decrease occurred for the cold worked steel. In both conditions, a steel containing a combination of all the alloying elements was most stable and had the best strength after thermal aging 5000 h at 600 degrees C. Despite having much higher strength than 316 stainless steel after aging, the ductility of the strongest experimental alloy was still as good as that of 316 stainless steel

A prebiotic, Celmanax™, decreases Escherichia coli O157:H7 colonization of bovine cells and feed-associated cytotoxicity in vitro

Directory of Open Access Journals (Sweden)

Juba Jean

2011-04-01

expressed Stx1 and Stx2, but more significantly, Stxs were also present in the blood clot blocking the jejunum. Mycotoxin analysis of the corn crop confirmed the presence of fumonisin, NIV, ZEAR, DON, 15-ADON, 3-ADON, NEO, DAS, HT-2 and T-2. Feed extracts were toxic to enterocytes and 0.1% Celmanax™ removed the cytotoxicity in vitro. There was no effect of Dairyman's Choice™ paste on feed-extract activity in vitro. Fumonisin, T-2, ZEAR and DON were toxic to bovine cells and 0.1% Celmanax™ removed the cytotoxicity in vitro. Celmanax™ also directly decreased E. coli O157:H7 colonization of mucosal explants and a colonic cell line in a dose-dependent manner. There was no effect of Dairyman's Choice™ paste on E. coli O157:H7 colonization in vitro. The inclusion of the prebiotic and probiotic in the feed was associated with a decline in disease. Conclusion The current study confirmed an association between mycotoxigenic fungi in the feed and the development of JHS in cattle. This association was further expanded to include mycotoxins in the feed and mixtures of STECs colonizing the severely hemorrhaged tissues. Future studies should examine the extent of involvement of the different STEC in the infection process. The prebiotic, Celmanax™, acted as an anti-adhesive for STEC colonization and a mycotoxin binder in vitro. Future studies should determine the extent of involvement of the prebiotic in altering disease.

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.

Effect of the manganese in (Pb1-x Lax) TiO3 piezoelectric ceramics

International Nuclear Information System (INIS)

Garcia, D.; Eiras, J.A.

1990-01-01

Measurements of the relative dielectric constant K, the electric dissipation factor tan δ and the electrochemical coupling factors of the thickness k t and planar K p vibration modes were realized in lead titanate piezoelectric ceramics, with batched composition (Pb 1-3/2x La x )TiO 3 , 0,025 ≤ x ≤0,20. The same parameters were determined in these compositions after the addition of 1%mol of Mn. The results shown clearly that manganese increases the electrochanical anisotropy (K t /K p ) and decreases the dielectric constant and the electric dissipation factor of these materials. (author) [pt

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.

In vitro generation of polysialylated cervical mucins by bacterial polysialyltransferases to counteract cytotoxicity of extracellular histones.

Science.gov (United States)

Galuska, Sebastian P; Galuska, Christina E; Tharmalingam, Tharmala; Zlatina, Kristina; Prem, Gerlinde; Husejnov, Farzali C O; Rudd, Pauline M; Vann, Willie F; Reid, Colm; Vionnet, Justine; Gallagher, Mary E; Carrington, Faye A; Hassett, Sarah-Louise; Carrington, Stephen D

2017-06-01

Neutrophil extracellular traps (NET) are formed against pathogens. However, various diseases are directly linked to this meshwork of DNA. The cytotoxic properties of extracellular histones especially seem to be an important trigger during these diseases. Furthermore, NET accumulation on implants is discussed to result in an impaired efficiency or failure, depending on the category of implant. Interestingly, mucins have been investigated as surface coatings potentially capable of reducing neutrophil adhesion. Similarly, polysialic acid was shown to inactivate the cytotoxic properties of extracellular histones. We wanted to combine the probability to decrease the adhesion of neutrophils using mucins with the capability of sialic acid polymers to counteract histone-mediated cytotoxicity. To this end, we elongate cervical mucins using bacterial polysialyltransferases. Subsequent cell-based experiments demonstrated the activity of elongated mucins against histone-mediated cytotoxicity. Thus, polysialylated mucins may represent a novel component to coat implants or to combat diseases with exaggerated NET formation. © 2017 Federation of European Biochemical Societies.

Molecular cytotoxic mechanisms of anticancer hydroxychalcones.

Science.gov (United States)

Sabzevari, Omid; Galati, Giuseppe; Moridani, Majid Y; Siraki, Arno; O'Brien, Peter J

2004-06-30

Chalcones are being considered as anticancer agents as they are natural compounds that are particularly cytotoxic towards K562 leukemia or melanoma cells. In this study, we have investigated phloretin, isoliquiritigenin, and 10 other hydroxylated chalcones for their cytotoxic mechanisms towards isolated rat hepatocytes. All hydroxychalcones partly depleted hepatocyte GSH and oxidized GSH to GSSG. These chalcones also caused a collapse of mitochondrial membrane potential and increased oxygen uptake. Furthermore, glycolytic or citric acid cycle substrates prevented cytotoxicity and mitochondrial membrane potential collapse. The highest pKa chalcones were the most effective at collapsing the mitochondrial membrane potential which suggests that the cytotoxic activity of hydroxychalcones are likely because of their ability to uncouple mitochondria.

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.

In vitro cytotoxicity of Manville Code 100 glass fibers: Effect of fiber length on human alveolar macrophages

Directory of Open Access Journals (Sweden)

Jones William

2006-03-01

Full Text Available Abstract Background Synthetic vitreous fibers (SVFs are inorganic noncrystalline materials widely used in residential and industrial settings for insulation, filtration, and reinforcement purposes. SVFs conventionally include three major categories: fibrous glass, rock/slag/stone (mineral wool, and ceramic fibers. Previous in vitro studies from our laboratory demonstrated length-dependent cytotoxic effects of glass fibers on rat alveolar macrophages which were possibly associated with incomplete phagocytosis of fibers ≥ 17 μm in length. The purpose of this study was to examine the influence of fiber length on primary human alveolar macrophages, which are larger in diameter than rat macrophages, using length-classified Manville Code 100 glass fibers (8, 10, 16, and 20 μm. It was hypothesized that complete engulfment of fibers by human alveolar macrophages could decrease fiber cytotoxicity; i.e. shorter fibers that can be completely engulfed might not be as cytotoxic as longer fibers. Human alveolar macrophages, obtained by segmental bronchoalveolar lavage of healthy, non-smoking volunteers, were treated with three different concentrations (determined by fiber number of the sized fibers in vitro. Cytotoxicity was assessed by monitoring cytosolic lactate dehydrogenase release and loss of function as indicated by a decrease in zymosan-stimulated chemiluminescence. Results Microscopic analysis indicated that human alveolar macrophages completely engulfed glass fibers of the 20 μm length. All fiber length fractions tested exhibited equal cytotoxicity on a per fiber basis, i.e. increasing lactate dehydrogenase and decreasing chemiluminescence in the same concentration-dependent fashion. Conclusion The data suggest that due to the larger diameter of human alveolar macrophages, compared to rat alveolar macrophages, complete phagocytosis of longer fibers can occur with the human cells. Neither incomplete phagocytosis nor length-dependent toxicity was

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

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.

Quantifying engineered nanomaterial toxicity: comparison of common cytotoxicity and gene expression measurements

Directory of Open Access Journals (Sweden)

Donald H. Atha

2017-11-01

Full Text Available Abstract Background When evaluating the toxicity of engineered nanomaterials (ENMS it is important to use multiple bioassays based on different mechanisms of action. In this regard we evaluated the use of gene expression and common cytotoxicity measurements using as test materials, two selected nanoparticles with known differences in toxicity, 5 nm mercaptoundecanoic acid (MUA-capped InP and CdSe quantum dots (QDs. We tested the effects of these QDs at concentrations ranging from 0.5 to 160 µg/mL on cultured normal human bronchial epithelial (NHBE cells using four common cytotoxicity assays: the dichlorofluorescein assay for reactive oxygen species (ROS, the lactate dehydrogenase assay for membrane viability (LDH, the mitochondrial dehydrogenase assay for mitochondrial function, and the Comet assay for DNA strand breaks. Results The cytotoxicity assays showed similar trends when exposed to nanoparticles for 24 h at 80 µg/mL with a threefold increase in ROS with exposure to CdSe QDs compared to an insignificant change in ROS levels after exposure to InP QDs, a twofold increase in the LDH necrosis assay in NHBE cells with exposure to CdSe QDs compared to a 50% decrease for InP QDs, a 60% decrease in the mitochondrial function assay upon exposure to CdSe QDs compared to a minimal increase in the case of InP and significant DNA strand breaks after exposure to CdSe QDs compared to no significant DNA strand breaks with InP. High-throughput quantitative real-time polymerase chain reaction (qRT-PCR data for cells exposed for 6 h at a concentration of 80 µg/mL were consistent with the cytotoxicity assays showing major differences in DNA damage, DNA repair and mitochondrial function gene regulatory responses to the CdSe and InP QDs. The BRCA2, CYP1A1, CYP1B1, CDK1, SFN and VEGFA genes were observed to be upregulated specifically from increased CdSe exposure and suggests their possible utility as biomarkers for toxicity. Conclusions This study can

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 ...

Antioxidant, pro-oxidant and cytotoxic properties of parsley.

Science.gov (United States)

Dorman, H J Damien; Lantto, Tiina A; Raasmaja, Atso; Hiltunen, Raimo

2011-06-01

Parsley (Petroselinum crispum) leaves were macerated with a mixture of methanol: water: acetic acid to produce a crude extract which was then defatted with (40°-60°) petrol. Antioxidant activity of the extract was evaluated using a battery of in vitro assays, viz., iron(iii) reduction, iron(ii) chelation and free radical scavenging assays. Evaluation of the pro-oxidant activity of the extract was based upon its effects upon DNA fragmentation and protein carbonylation. Cytotoxicity and apoptotic effects of the extract were determined in non-cancerous CV1-P fibroblast and cancerous A375 melanoma cells using MTT and LDH tests and caspase 3-like activity assay. The highest concentration, 2.0 mg ml(-1), decreased the viability of both cell lines, however, the cancerous melanoma cells were slightly susceptible to the effects. The observed cytotoxicity was not due to the caspase 3 activity. In conclusion, the toxicity might be explained by the pro-oxidative activity of components within the extract against proteins and/or DNA but it is not related to caspase 3-dependent apoptosis within cells.

Cytotoxicity of titanium dioxide nanoparticles in mouse fibroblast cells.

Science.gov (United States)

Jin, Cheng-Yu; Zhu, Bang-Shang; Wang, Xue-Feng; Lu, Qing-Hua

2008-09-01

Nanotitanium dioxide (TiO2) is an important industrial material that is widely used as an additive in cosmetics, pharmaceuticals, and food colorants. Although the small size of the TiO2 nanoparticle is useful in various applications, the biosafety of this material needs to be evaluated. In this study, mouse fibroblast (L929) cells were used to evaluate the cytotoxicity of different concentrations (3-600 microg/mL) of homogeneous and weakly aggregated TiO2 nanoparticles in aqueous solution. The L929 cells became round and even shrank as the concentration of TiO2 nanoparticles increased. Moreover, TiO2 nanoparticle-treated cells had condensed fragmented chromatin or were directly necrosed, as observed by acridine orange (AO) staining. The transmission electron microscopy (TEM) analysis showed that in cells cultured in a medium containing 300 microg/mL TiO2, the number of lysosomes increased, and some cytoplasmic organelles were damaged. In addition, there was a significant increase in oxidative stress at higher TiO2 nanoparticle concentrations (>60 microg/mL). As the concentration of TiO2 nanoparticles increased in the culture medium, the levels of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) increased, while those of methyl tetrazolium cytotoxicity (MTT), glutathione (GSH), and superoxide dismutase (SOD) decreased. A possible mechanism for the cytotoxicity of TiO2 nanoparticles is also discussed.

Assessment of in vitro genotoxic and cytotoxic effects of flurbiprofen on human cultured lymphocytes.

Science.gov (United States)

Timocin, Taygun; Ila, Hasan Basri; Dordu, Tuba; Husunet, Mehmet Tahir; Tazehkand, Mostafa Norizadeh; Valipour, Ebrahim; Topaktas, Mehmet

2016-01-01

Flurbiprofen is non-steroidal anti-inflammatory drug which is commonly used for its analgesic, antipyretic, and anti-inflammatory effects. The purpose of the study was to explore the genotoxic and cytotoxic effects of flurbiprofen in human cultured lymphocytes by sister chromatid exchange, chromosome aberration, and cytokinesis-blocked micronucleus tests. 10, 20, 30, and 40 μg/mL concentrations of flurbiprofen (solvent is DMSO) were used to treatment of human cultured lymphocytes at two different treatment periods (24 and 48 h). Flurbiprofen had no significant genotoxic effect in any of these tests. But exposing to flurbiprofen for 24 and 48 h led to significant decrease on proliferation index, mitotic index, and nuclear division index (NDI). Also, all decreases were concentration-dependent (except NDI at 24 h treatment period). Consequently, the findings of this research showed that flurbiprofen had cytotoxic effects in human blood lymphocytes.

Cytotoxicity of cadmium-containing quantum dots based on a study using a microfluidic chip

International Nuclear Information System (INIS)

Zheng Xiannuo; Weng Lixing; Tian Jing; Wang Lianhui; Wu Lei; Jin Qinghui; Zhao Jianlong

2012-01-01

There is a lack of reliable nanotoxicity assays available for monitoring and quantifying multiple cellular events in cultured cells. In this study, we used a microfluidic chip to systematically investigate the cytotoxicity of three kinds of well-characterized cadmium-containing quantum dots (QDs) with the same core but different shell structures, including CdTe core QDs, CdTe/CdS core–shell QDs, and CdTe/CdS/ZnS core–shell–shell QDs, in HEK293 cells. Using the microfluidic chip combined with fluorescence microscopy, multiple QD-induced cellular events including cell morphology, viability, proliferation, and QD uptake were simultaneously analysed. The three kinds of QDs showed significantly different cytotoxicities. The CdTe QDs, which are highly toxic to HEK293 cells, resulted in remarkable cellular and nuclear morphological changes, a dose-dependent decrease in cell viability, and strong inhibition of cell proliferation; the CdTe/CdS QDs were moderately toxic but did not significantly affect the proliferation of HEK293 cells; while the CdTe/CdS/ZnS QDs had no detectable influence on cytotoxicity with respect to cell morphology, viability, and proliferation. Our data indicated that QD cytotoxicity was closely related to their surface structures and specific physicochemical properties. This study also demonstrated that the microfluidic chip could serve as a powerful tool to systematically evaluate the cytotoxicity of nanoparticles in multiple cellular events. (paper)

Cytotoxicity of cadmium-containing quantum dots based on a study using a microfluidic chip

Science.gov (United States)

Zheng, Xiannuo; Tian, Jing; Weng, Lixing; Wu, Lei; Jin, Qinghui; Zhao, Jianlong; Wang, Lianhui

2012-02-01

There is a lack of reliable nanotoxicity assays available for monitoring and quantifying multiple cellular events in cultured cells. In this study, we used a microfluidic chip to systematically investigate the cytotoxicity of three kinds of well-characterized cadmium-containing quantum dots (QDs) with the same core but different shell structures, including CdTe core QDs, CdTe/CdS core-shell QDs, and CdTe/CdS/ZnS core-shell-shell QDs, in HEK293 cells. Using the microfluidic chip combined with fluorescence microscopy, multiple QD-induced cellular events including cell morphology, viability, proliferation, and QD uptake were simultaneously analysed. The three kinds of QDs showed significantly different cytotoxicities. The CdTe QDs, which are highly toxic to HEK293 cells, resulted in remarkable cellular and nuclear morphological changes, a dose-dependent decrease in cell viability, and strong inhibition of cell proliferation; the CdTe/CdS QDs were moderately toxic but did not significantly affect the proliferation of HEK293 cells; while the CdTe/CdS/ZnS QDs had no detectable influence on cytotoxicity with respect to cell morphology, viability, and proliferation. Our data indicated that QD cytotoxicity was closely related to their surface structures and specific physicochemical properties. This study also demonstrated that the microfluidic chip could serve as a powerful tool to systematically evaluate the cytotoxicity of nanoparticles in multiple cellular events.

Kinetics and Mechanism of Paracetamol Oxidation by Chromium(VI in Absence and Presence of Manganese(II and Sodiumdodecyl Sulphate

Directory of Open Access Journals (Sweden)

Maqsood Ahmad Malik

2007-11-01

Full Text Available The kinetics of paracetamol oxidation are first order each in [paracetamol] and [HClO4]. The kinetic study shows that the oxidation proceeds in two steps. The effects of anionic micelles of sodiumdodecyl sulphate (SDS and complexing agents (ethylenediammine tetraacetic acid (EDTA and 2,2′-bipyridyl (bpy were also studied. Fast kinetic spectrophotometric method has been described for the determination of paracetamol. The method is based on the catalytic effect of manganese(II on the oxidation of paracetamol by chromium(VI in the presence of HClO4 (= 0.23 mol dm−3. Optimum reaction time is 4 to 6 minutes at a temperature of 30∘C. The addition of manganese(II ions largely decreased the absorbance of chromium(VI at 350 nm. This reaction can be utilized for the determination of paracetamol in drugs.

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

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.

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

International Nuclear Information System (INIS)

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

2003-01-01

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

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

Science.gov (United States)

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

2003-09-15

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

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.

A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus

International Nuclear Information System (INIS)

McAdam, M.E.; Lavelle, F.; Fox, R.A.; Fielden, E.M.

1977-01-01

The mechanism of catalysis of the manganese-containing superoxide dismutase from Bacillus stearothermophilus has been shown to involve a 'fast cycle' and a 'slow cycle' (McAdam, M.E., Fox, R.A., Lavelle, F., and Fielden, E.M., Biochem. J.; 165:71 (1977)). Further properties of the enzyme are now considered. Pulse-radiolysis studies, under conditions of low substrate concentration to enzyme concentration (i.e. when the fast cycle predominates), showed that enzyme activity decreases as pH increases (6.5 to 10.2). Activity was unaffected by the addition of H 2 O 2 or NaN 3 but slightly decreased by KCN. Both H 2 O 2 and the reducing radical anion CO 2 sup(-.) caused a decrease in A 480 of the native enzyme. The rate of the fast catalytic cycle was independent of temperature (5 to 55 0 C), and as temperature increased the slow catalytic cycle became relatively more important. Arrhenius parameters of the rate constants were estimated. The possible identity of the various forms of the enzyme is considered. (author)

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

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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.

Highly Chemo- and Stereoselective Transfer Semihydrogenation of Alkynes Catalyzed by a Stable, Well-defined Manganese(II) Complex

KAUST Repository

Brzozowska, Aleksandra; Azofra, Luis Miguel; Zubar, Viktoriia; Atodiresei, Iuliana; Cavallo, Luigi; Rueping, Magnus; El-Sepelgy, Osama

2018-01-01

The first example of manganese catalyzed semihydrogenation of internal alkynes to (Z)-alkenes using ammonia borane as a hydrogen donor is reported. The reaction is catalyzed by a pincer complex of the earth abundant manganese(II) salt in the absence of any additives, base or super hydride. The ammonia borane smoothly reduces the manganese pre-catalyst [Mn(II)-PNP][Cl]2 to the catalytically active species [Mn(I)-PNP]-hydride in the triplet spin state. This manganese hydride is highly stabilized by complexation with the alkyne substrate. Computational DFT analysis studies of the reaction mechanism rationalizes the origin of stereoselectivity towards formation of (Z)-alkenes.

Highly Chemo- and Stereoselective Transfer Semihydrogenation of Alkynes Catalyzed by a Stable, Well-defined Manganese(II) Complex

KAUST Repository

Brzozowska, Aleksandra

2018-03-30

The first example of manganese catalyzed semihydrogenation of internal alkynes to (Z)-alkenes using ammonia borane as a hydrogen donor is reported. The reaction is catalyzed by a pincer complex of the earth abundant manganese(II) salt in the absence of any additives, base or super hydride. The ammonia borane smoothly reduces the manganese pre-catalyst [Mn(II)-PNP][Cl]2 to the catalytically active species [Mn(I)-PNP]-hydride in the triplet spin state. This manganese hydride is highly stabilized by complexation with the alkyne substrate. Computational DFT analysis studies of the reaction mechanism rationalizes the origin of stereoselectivity towards formation of (Z)-alkenes.

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.

Energy metabolism in astrocytes and neurons treated with manganese: relation among cell-specific energy failure, glucose metabolism, and intercellular trafficking using multinuclear NMR-spectroscopic analysis.

Science.gov (United States)

Zwingmann, Claudia; Leibfritz, Dieter; Hazell, Alan S

2003-06-01

A central question in manganese neurotoxicity concerns mitochondrial dysfunction leading to cerebral energy failure. To obtain insight into the underlying mechanism(s), the authors investigated cell-specific pathways of [1-13C]glucose metabolism by high-resolution multinuclear NMR-spectroscopy. Five-day treatment of neurons with 100-micro mol/L MnCl(2) led to 50% and 70% decreases of ATP/ADP and phosphocreatine-creatine ratios, respectively. An impaired flux of [1-13C]glucose through pyruvate dehydrogenase, which was associated with Krebs cycle inhibition and hence depletion of [4-13C]glutamate, [2-13C]GABA, and [13C]glutathione, hindered the ability of neurons to compensate for mitochondrial dysfunction by oxidative glucose metabolism and further aggravated neuronal energy failure. Stimulated glycolysis and oxidative glucose metabolism protected astrocytes against energy failure and oxidative stress, leading to twofold increased de novo synthesis of [3-13C]lactate and fourfold elevated [4-13C]glutamate and [13C]glutathione levels. Manganese, however, inhibited the synthesis and release of glutamine. Comparative NMR data obtained from cocultures showed disturbed astrocytic function and a failure of astrocytes to provide neurons with substrates for energy and neurotransmitter metabolism, leading to deterioration of neuronal antioxidant capacity (decreased glutathione levels) and energy metabolism. The results suggest that, concomitant to impaired neuronal glucose oxidation, changes in astrocytic metabolism may cause a loss of intercellular homeostatic equilibrium, contributing to neuronal dysfunction in manganese neurotoxicity.

A Manganese Superoxide Dismutase (SOD2 Gene Polymorphism in Insulin-Dependent Diabetes Mellitus

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Flemming Pociot

1993-01-01

Full Text Available Interleukin I (lL-I is selectively cytotoxic to the insulin producing beta cell of pancreatic islets. This effect may be due to IL-I induced generation of reactive oxygen species and nitric oxide. Since beta cells contain low amounts of the superoxide radical scavenger enzyme manganese superoxide dismutase (MnSOD, this may leave beta cells more susceptible to IL-I than other cell types. Genetic variation in the MnSOD locus could reflect differences in scavenger potential. We, therefore, studied possible restriction fragment length polymorphisms (RFLPs of this locus in patients with insulin-dependent diabetes mellitus (100M (n= 154 and control individuals (n=178, Taql revealed a double diallelic RFLP in patients as well as in controls. No overall difference in allelic or genotype frequencies were observed between 100M patients and control individuals (p=0.11 and no significant association of any particular RFLP pattern with 100M was found. Structurally polymorphic MnSOD protein variants with altered activities have been reported. If genetic variation results in MnSOD variants with reduced activities, the MnSOD locus may still be a candidate gene for 100M susceptibility. Whether the RFLPs reported in this study reflects differences in gene expression level, protein level and/or specific activity of the protein is yet to be studied.

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 ...

Cytotoxic glucosphingolipid from Celtis Africana.

Science.gov (United States)

Perveen, Shagufta; Al-Taweel, Areej Mohammad; Fawzy, Ghada Ahmed; El-Shafae, Azza Muhammed; Khan, Afsar; Proksch, Peter

2015-05-01

Literature survey proved the use of the powdered sun-dried bark and roots of Celtis africana for the treatment of cancer in South Africa. The aim of this study was to do further isolation work on the ethyl acetate fraction and to investigate the cytotoxic activities of the various fractions and isolated compound. Cytotoxicity of petroleum ether, chloroform, ethyl acetate, n-butanol fractions and compound 1 were tested on mouse lymphoma cell line L5178Y using the microculture tetrazolium assay. One new glucosphingolipid 1 was isolated from the aerial parts of C. africana. The structure of the new compound was determined by extensive analysis by one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy and mass spectrometry. The ethyl acetate fraction and compound 1 showed strong cytotoxic activity with an EC50 value of 8.3 μg/mL and 7.8 μg/mL, respectively, compared with Kahalalide F positive control (6.3 μg/mL). This is the first report of the occurrence of a cytotoxic glucosphingolipid in family Ulmaceae.

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

Retained sensitivity to cytotoxic pyrimidine nucleoside analogs in thymidine kinase 2 deficient human fibroblasts.

Science.gov (United States)

Bjerke, Mia; Solaroli, Nicola; Lesko, Nicole; Balzarini, Jan; Johansson, Magnus; Karlsson, Anna

2010-01-01

Thymidine kinase 2 (TK2) is a mitochondrial deoxyribonucleoside kinase that phosphorylates several nucleoside analogs used in anti-viral and anti-cancer therapy. A fibroblast cell line with decreased TK2 activity was investigated in order to obtain insights in the effects of TK2 deficiency on nucleotide metabolism. The role of TK2 for the sensitivity against cytotoxic nucleoside analogs was also investigated. The TK2 deficient cells retained their sensitivity against all pyrimidine nucleoside analogs tested. This study suggests that nucleoside analog phosphorylation mediated by TK2 may be less important, compared to other deoxyribonucleoside kinases, for the cytotoxic effects of these compounds.

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)

4-IBP, a σ1 Receptor Agonist, Decreases the Migration of Human Cancer Cells, Including Glioblastoma Cells, In Vitro and Sensitizes Them In Vitro and In Vivo to Cytotoxic Insults of Proapoptotic and Proautophagic Drugs

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Veronique Mégalizzi

2007-05-01

Full Text Available Although the molecular function of cr receptors has not been fully defined and the natural ligand(s is still not known, there is increasing evidence that these receptors and their ligands might play a significant role in cancer biology. 4-(N-tibenzylpiperidin-4-yl-4iodobenzamide (4-IBP, a selective σ1, agonist, has been used to investigate whether this compound is able to modify: 1 in vitro the migration and proliferation of human cancer cells; 2 in vitro the sensitivity of human glioblastoma cells to cytotoxic drugs; and 3 in vivo in orthotopic glioblastoma and non-small cell lung carcinoma (NSCLC models the survival of mice coadministered cytotoxic agents. 4-IBP has revealed weak anti proliferative effects on human U373-MG glioblastoma and C32 melanoma cells but induced marked concentration-dependent decreases in the growth of human A549 NSCLC and PC3 prostate cancer cells. The compound was also significantly antimigratory in all four cancer cell lines. This may result, at least in U373-MG cells, from modifications to the actin cytoskeleton. 4-IBP modified the sensitivity of U373-MG cells in vitro to proapoptotic lomustin and proautophagic temozolomide, and markedly decreased the expression of two proteins involved in drug resistance: glucosylceramide synthase and Rho guanine nucleotide dissociation inhibitor. In vivo, 4-IBP increased the antitumor effects of temozolomide and irinotecan in immunodeficient mice that were orthotopically grafted with invasive cancer cells.

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

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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)

The role of the Parkinson's disease gene PARK9 in essential cellular pathways and the manganese homeostasis network in yeast.

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Alessandra Chesi

Full Text Available YPK9 (Yeast PARK9; also known as YOR291W is a non-essential yeast gene predicted by sequence to encode a transmembrane P-type transport ATPase. However, its substrate specificity is unknown. Mutations in the human homolog of YPK9, ATP13A2/PARK9, have been linked to genetic forms of early onset parkinsonism. We previously described a strong genetic interaction between Ypk9 and another Parkinson's disease (PD protein α-synuclein in multiple model systems, and a role for Ypk9 in manganese detoxification in yeast. In humans, environmental exposure to toxic levels of manganese causes a syndrome similar to PD and is thus an environmental risk factor for the disease. How manganese contributes to neurodegeneration is poorly understood. Here we describe multiple genome-wide screens in yeast aimed at defining the cellular function of Ypk9 and the mechanisms by which it protects cells from manganese toxicity. In physiological conditions, we found that Ypk9 genetically interacts with essential genes involved in cellular trafficking and the cell cycle. Deletion of Ypk9 sensitizes yeast cells to exposure to excess manganese. Using a library of non-essential gene deletions, we screened for additional genes involved in tolerance to excess manganese exposure, discovering several novel pathways involved in manganese homeostasis. We defined the dependence of the deletion strain phenotypes in the presence of manganese on Ypk9, and found that Ypk9 deletion modifies the manganese tolerance of only a subset of strains. These results confirm a role for Ypk9 in manganese homeostasis and illuminates cellular pathways and biological processes in which Ypk9 likely functions.

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)

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.

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)

Calcium Contributes to the Cytotoxic Interaction Between Diclofenac and Cytokines.

Science.gov (United States)

Maiuri, Ashley R; Breier, Anna B; Turkus, Jonathan D; Ganey, Patricia E; Roth, Robert A

2016-02-01

Diclofenac (DCLF) is a widely used non-steroidal anti-inflammatory drug that is associated with idiosyncratic, drug-induced liver injury (IDILI) in humans. The mechanisms of DCLF-induced liver injury are unknown; however, patients with certain inflammatory diseases have an increased risk of developing IDILI, which raises the possibility that immune mediators play a role in the pathogenesis. DCLF synergizes with the cytokines tumor necrosis factor-alpha (TNF) and interferon-gamma (IFN) to cause hepatocellular apoptosis in vitro by a mechanism that involves activation of the endoplasmic reticulum (ER) stress response pathway and of the mitogen-activated protein kinases, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). DCLF also causes an increase in intracellular calcium (Ca(++)) in hepatocytes, but the role of this in the cytotoxic synergy between DCLF and cytokines is unknown. We tested the hypothesis that Ca(++) contributes to DCLF/cytokine-induced cytotoxic synergy. Treatment of HepG2 cells with DCLF led to an increase in intracellular Ca(++) at 6 and 12 h, and this response was augmented in the presence of TNF and IFN at 12 h. The intracellular Ca(++) chelator BAPTA/AM reduced cytotoxicity and caspase-3 activation caused by DCLF/cytokine cotreatment. BAPTA/AM also significantly reduced DCLF-induced activation of the ER stress sensor, protein kinase RNA-like ER kinase (PERK), as well as activation of JNK and ERK. Treatment of cells with an inositol trisphosphate receptor antagonist almost completely eliminated DCLF/cytokine-induced cytotoxicity and decreased DCLF-induced activation of PERK, JNK, and ERK. These findings indicate that Ca(++) contributes to DCLF/cytokine-induced cytotoxic synergy by promoting activation of the ER stress-response pathway and JNK and ERK. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

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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

Impact of diffusion barriers to small cytotoxic molecules on the efficacy of immunotherapy in breast cancer.

Directory of Open Access Journals (Sweden)

Hiranmoy Das

Full Text Available Molecular-focused cancer therapies, e.g., molecularly targeted therapy and immunotherapy, so far demonstrate only limited efficacy in cancer patients. We hypothesize that underestimating the role of biophysical factors that impact the delivery of drugs or cytotoxic cells to the target sites (for associated preferential cytotoxicity or cell signaling modulation may be responsible for the poor clinical outcome. Therefore, instead of focusing exclusively on the investigation of molecular mechanisms in cancer cells, convection-diffusion of cytotoxic molecules and migration of cancer-killing cells within tumor tissue should be taken into account to improve therapeutic effectiveness. To test this hypothesis, we have developed a mathematical model of the interstitial diffusion and uptake of small cytotoxic molecules secreted by T-cells, which is capable of predicting breast cancer growth inhibition as measured both in vitro and in vivo. Our analysis shows that diffusion barriers of cytotoxic molecules conspire with γδ T-cell scarcity in tissue to limit the inhibitory effects of γδ T-cells on cancer cells. This may increase the necessary ratios of γδ T-cells to cancer cells within tissue to unrealistic values for having an intended therapeutic effect, and decrease the effectiveness of the immunotherapeutic treatment.

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

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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.

Neutralization study of boron and some metallic impurities (gold, titanium, manganese, chromium) by hydrogen implantation in monocrystal silicon

International Nuclear Information System (INIS)

Zundel, T.

1987-02-01

Boron doped silicon implanted with hydrogen at low energy in the temperature range 80-140 0 C shows a large decrease of the electrically active dopant concentration up to a depth which increases with the temperature, the implantation duration and the starting material resistivity. This effect is assigned to the formation of an electrically inactive BH complex. The hydrogen incorporation process shows a weakly temperature dependent enhanced diffusion step followed by a normal diffusion phase which may be described by a thermally activated diffusion coefficient. Heating at 80 0 C produces a complete dissociation of the BH complexes in the space charge region of reverse biased Schottky diodes. Consequently the released hydrogen drifts under the electric field and the neutralization becomes more pronounced in the bulk. Hydrogen neutralizes the gold, chromium, manganese related deep levels but has no effect on titanium related defect levels. Thermal annealing at 495 0 C of hydrogenated chromium or manganese doped samples produces four majority carriers levels which disappear at 700 0 C [fr

Comparison of mammalian and fish cell line cytotoxicity: impact of endpoint and exposure duration

International Nuclear Information System (INIS)

Guelden, Michael; Moerchel, Sabine; Seibert, Hasso

2005-01-01

Comparisons of acute toxic concentrations of chemicals to fish in vivo and cytotoxic concentrations to fish cell lines in vitro reveal rather good correlations of the toxic potencies in vitro and in vivo, but a clearly lower sensitivity of the fish cells. To examine whether the low sensitivity is specific for fish cells, cytotoxic potencies of reference chemicals from the Multicenter Evaluation of In Vitro Cytotoxicity program (MEIC) reported for the fish cell lines R1 and RTG-2 were compared with those obtained with the mouse Balb/c 3T3 cell line. Cytotoxic potencies (EC 50 values) for MEIC reference chemicals were determined with exponentially growing Balb/c 3T3 cells using three different test protocols. To assess both endpoints, cell proliferation and cell survival, EC 50 values were measured for the decrease in final cell protein after 24 and 72 h of exposure and for the reduction of cell protein increase during 24 h of exposure. EC 50 values obtained with the fish cell lines R1 and RTG-2 using cell survival as endpoint were taken from the MEIC data base. The comparison of cytotoxic potencies shows that, in general, the fish cell lines and the mammalian cell line are almost equally sensitive towards the cytotoxic action of chemicals. The mammalian cell line assay, however, becomes considerably more sensitive, by factors of 3.4-8.5, than the fish cell line assays, if cell growth instead of cell survival is used as endpoint. It is concluded, that cell proliferation might be a better endpoint than cell survival and that mammalian cell lines might be suited to assess fish acute toxicity

Astaxanthin down-regulates Rad51 expression via inactivation of AKT kinase to enhance mitomycin C-induced cytotoxicity in human non-small cell lung cancer cells.

Science.gov (United States)

Ko, Jen-Chung; Chen, Jyh-Cheng; Wang, Tai-Jing; Zheng, Hao-Yu; Chen, Wen-Ching; Chang, Po-Yuan; Lin, Yun-Wei

2016-04-01

Astaxanthin has been demonstrated to exhibit a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. However, the molecular mechanism of astaxanthin-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Rad51 plays a central role in homologous recombination, and studies show that chemo-resistant carcinomas exhibit high levels of Rad51 expression. In this study, astaxanthin treatment inhibited cell viability and proliferation of two NSCLC cells, A549 and H1703. Astaxanthin treatment (2.5-20 μM) decreased Rad51 expression and phospho-AKT(Ser473) protein level in a time and dose-dependent manner. Furthermore, expression of constitutively active AKT (AKT-CA) vector rescued the decreased Rad51 mRNA and protein levels in astaxanthin-treated NSCLC cells. Combined treatment with phosphatidylinositol 3-kinase (PI3K) inhibitors (LY294002 or wortmannin) further decreased the Rad51 expression in astaxanthin-exposed A549 and H1703 cells. Knockdown of Rad51 expression by transfection with si-Rad51 RNA or cotreatment with LY294002 further enhanced the cytotoxicity and cell growth inhibition of astaxanthin. Additionally, mitomycin C (MMC) as an anti-tumor antibiotic is widely used in clinical NSCLC chemotherapy. Combination of MMC and astaxanthin synergistically resulted in cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced phospho-AKT(Ser473) level and Rad51 expression. Overexpression of AKT-CA or Flag-tagged Rad51 reversed the astaxanthin and MMC-induced synergistic cytotoxicity. In contrast, pretreatment with LY294002 further decreased the cell viability in astaxanthin and MMC co-treated cells. In conclusion, astaxanthin enhances MMC-induced cytotoxicity by decreasing Rad51 expression and AKT activation. These findings may provide rationale to combine astaxanthin with MMC for the treatment of NSCLC. Copyright © 2016 Elsevier Inc. All rights reserved.

Cytotoxic Effects of Bangladeshi Medicinal Plant Extracts

Directory of Open Access Journals (Sweden)

Shaikh J. Uddin

2011-01-01

Full Text Available To investigate the cytotoxic effect of some Bangladeshi medicinal plant extracts, 16 Bangladeshi medicinal plants were successively extracted with n-hexane, dichloromethane, methanol and water. The methanolic and aqueous extracts were screened for cytotoxic activity against healthy mouse fibroblasts (NIH3T3 and three human cancer-cell lines (gastric: AGS; colon: HT-29; and breast: MDA-MB-435S using the MTT assay. Two methanolic extracts (Hygrophila auriculata and Hibiscus tiliaceous and one aqueous extract (Limnophila indica showed no toxicity against healthy mouse fibroblasts, but selective cytotoxicity against breast cancer cells (IC50 1.1–1.6 mg mL−1. Seven methanolic extracts from L. indica, Clerodendron inerme, Cynometra ramiflora, Xylocarpus moluccensis, Argemone mexicana, Ammannia baccifera and Acrostichum aureum and four aqueous extracts from Hygrophila auriculata, Bruguiera gymnorrhiza, X. moluccensis and Aegiceras corniculatum showed low toxicity (IC50 > 2.5 mg mL−1 against mouse fibroblasts but selective cytotoxicity (IC50 0.2–2.3 mg mL−1 against different cancer cell lines. The methanolic extract of Blumea lacera showed the highest cytotoxicity (IC50 0.01–0.08 mg mL−1 against all tested cell lines among all extracts tested in this study. For some of the plants their traditional use as anticancer treatments correlates with the cytotoxic results, whereas for others so far unknown cytotoxic activities were identified.

Effect of Digestion and Storage of Human Milk on Free Fatty Acid Concentration and Cytotoxicity

Science.gov (United States)

Penn, Alexander H.; Altshuler, Angelina E.; Small, James W.; Taylor, Sharon F.; Dobkins, Karen R.; Schmid-Schönbein, Geert W.

2014-01-01

Objectives Fat is digested in the intestine into free fatty acids (FFAs), which are detergents and therefore toxic to cells at micromolar concentration. The mucosal barrier protects cells in the adult intestine, but this barrier may not be fully developed in premature infants. Lipase-digested infant formula, but not fresh human milk, has elevated FFAs and is cytotoxic to intestinal cells, and therefore could contribute to intestinal injury in necrotizing enterocolitis (NEC). But even infants exclusively fed breast milk may develop NEC. Our objective was to determine if stored milk and milk from donor milk banks (DM) could also become cytotoxic, especially after digestion. Methods We exposed cultured rat intestinal epithelial cells or human neutrophils to DM and milk collected fresh and stored at 4 or −20 °C for up to 12 weeks and then treated for 2 hours (37°C) with 0.1 or 1 mg/ml pancreatic lipase and/or trypsin and chymotrypsin. Results DM and milk stored 3 days (at 4 or −20 °C) and then digested were cytotoxic. Storage at −20 °C for 8 and 12 weeks resulted in an additional increase in cytotoxicity. Protease digestion decreased, but did not eliminate cell death. Conclusions Current storage practices may allow milk to become cytotoxic and contribute to intestinal damage in NEC. PMID:24840512

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.)

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.

Effect of molybdenum on the severity of toxicity symptoms in flax induced by an excess of either manganese, zinc, copper, nickel or cobalt in the nutrient solution

Energy Technology Data Exchange (ETDEWEB)

Millikan, C R

1947-01-01

The addition of molybdenum to solutions containing an excess of either manganese, zinc, copper, nickel or cobalt respectively, resulted in decreases in the severity of iron deficiency symptoms which normally occurred when flax was grown in solutions containing the same concentrations of any of these elements, but without molybdenum. The efficacy of molybdenum in this regard increased with increasing concentration up to 25 parts per million. However, concentrations of 0.5 to 2 parts per million of molybdenum had little effect on the severity of iron deficiency symptoms at the concentrations of heavy metals used. Molybdenum 5, 10 or 25 parts per million also retarded the date of appearance and reduced the severity of lower leaf necrosis which is another characteristic symptom of the presence of excess manganese (25 to 100 parts per million) in the nutrient solution. It is concluded that an essential function of molybdenum is intimately associated with the regulation of the deleterious effect of manganese, zinc, copper, nickel or cobalt on the physiological availability of iron to the plant. 46 references, 3 figures.

In vitro cytotoxicity of chemical preservatives on human fibroblast cells

Directory of Open Access Journals (Sweden)

Daniel Gonsales Spindola

2018-05-01

Full Text Available ABSTRACT Preservatives are widely used substances that are commonly added to various cosmetic and pharmaceutical products to prevent or inhibit microbial growth. In this study, we compared the in vitro cytotoxicity of different types of currently used preservatives, including methylparaben, imidazolidinyl urea (IMU, and sodium benzoate, using the human newborn fibroblast cell line CCD1072Sk. Of the tested preservatives, only IMU induced a reduction in cell viability, as shown using the MTT assay and propidium iodide staining (IMU>methylparaben>sodium benzoate. IMU was shown to promote homeostatic alterations potentially related to the initiation of programed cell death, such as decreased mitochondrial membrane potential and caspase-3 activation, in the treated cells. Methylparaben and sodium benzoate were shown to have a very low cytotoxic activity. Taken together, our results suggest that IMU induces programed cell death in human fibroblasts by a canonical intrinsic pathway via mitochondrial perturbation and subsequent release of proapoptotic factors.

Experimental study on viscosity of spinel-type manganese ferrite nanofluid in attendance of magnetic field

Energy Technology Data Exchange (ETDEWEB)

Amani, Mohammad, E-mail: m_amani@sbu.ac.ir [Mechanical and Energy Engineering Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Amani, Pouria, E-mail: pouria.amani@ut.ac.ir [Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Kasaeian, Alibakhsh, E-mail: akasa@ut.ac.ir [Department of Renewable Energies, Faculty of New Science & Technologies, University of Tehran, Tehran (Iran, Islamic Republic of); Mahian, Omid, E-mail: omid.mahian@mshdiau.ac.ir [Young Researchers and Elite Club, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Kasaeian, Fazel, E-mail: f.kasa92@student.sharif.edu [Faculty of Material Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Wongwises, Somchai, E-mail: somchai.won@kmutt.ac.th [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi (KMUTT), Bangmod, Bangkok (Thailand)

2017-04-15

In this paper, an experimental evaluation on the viscosity of water-based manganese ferrite nanofluid with and without magnetic field with 100, 200, 300, and 400 G intensities has been conducted. The Brookfield DV-I PRIME viscometer is implemented to measure the MnFe{sub 2}O{sub 4}/water nanofluid viscosity and to evaluate the influence of different volume concentrations (from 0.25% to 3%) and various temperatures (from 20 to 60 °C) on the viscosity. According to the measurements, viscosity incrementally increases with the augmentation of nanoparticles concentration while it remarkably decreases at higher temperatures under absence and attendance of magnetic field. The maximum viscosity ratio of 1.14 is achieved at 3 vol% of nanoparticles and 20 °C under no magnetic field, whereas it increments to maximum viscosity ratio of 1.75 at 3 vol% of nanoparticles and 40 °C under 400 G magnetic field. Furthermore, new correlation is proposed for determination of viscosity of MnFe{sub 2}O{sub 4}/water nanofluids in terms of magnetic field intensity, volume concentration and temperature. - Highlights: • Viscosity of spinel-type manganese ferrite nanofluids is measured. • Effect of a constant magnetic field on the viscosity is investigated. • A novel correlation is proposed for estimation of the measured viscosity.

Experimental study on viscosity of spinel-type manganese ferrite nanofluid in attendance of magnetic field

International Nuclear Information System (INIS)

Amani, Mohammad; Amani, Pouria; Kasaeian, Alibakhsh; Mahian, Omid; Kasaeian, Fazel; Wongwises, Somchai

2017-01-01

In this paper, an experimental evaluation on the viscosity of water-based manganese ferrite nanofluid with and without magnetic field with 100, 200, 300, and 400 G intensities has been conducted. The Brookfield DV-I PRIME viscometer is implemented to measure the MnFe 2 O 4 /water nanofluid viscosity and to evaluate the influence of different volume concentrations (from 0.25% to 3%) and various temperatures (from 20 to 60 °C) on the viscosity. According to the measurements, viscosity incrementally increases with the augmentation of nanoparticles concentration while it remarkably decreases at higher temperatures under absence and attendance of magnetic field. The maximum viscosity ratio of 1.14 is achieved at 3 vol% of nanoparticles and 20 °C under no magnetic field, whereas it increments to maximum viscosity ratio of 1.75 at 3 vol% of nanoparticles and 40 °C under 400 G magnetic field. Furthermore, new correlation is proposed for determination of viscosity of MnFe 2 O 4 /water nanofluids in terms of magnetic field intensity, volume concentration and temperature. - Highlights: • Viscosity of spinel-type manganese ferrite nanofluids is measured. • Effect of a constant magnetic field on the viscosity is investigated. • A novel correlation is proposed for estimation of the measured viscosity.

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.

IGF-1 promotes the development and cytotoxic activity of human NK cells

Science.gov (United States)

Ni, Fang; Sun, Rui; Fu, Binqing; Wang, Fuyan; Guo, Chuang; Tian, Zhigang; Wei, Haiming

2013-01-01

Insulin-like growth factor 1 (IGF-1) is a critical regulator of many physiological functions, ranging from longevity to immunity. However, little is known about the role of IGF-1 in natural killer cell development and function. Here, we identify an essential role for IGF-1 in the positive regulation of human natural killer cell development and cytotoxicity. Specifically, we show that human natural killer cells have the ability to produce IGF-1 and that differential endogenous IGF-1 expression leads to disparate cytotoxicity in human primary natural killer cells. Moreover, miR-483-3p is identified as a critical regulator of IGF-1 expression in natural killer cells. Overexpression of miR-483-3p has an effect similar to IGF-1 blockade and decreased natural killer cell cytotoxicity, whereas inhibition of miR-483-3p has the opposite effect, which is reversible with IGF-1 neutralizing antibody. These findings indicate that IGF-1 and miR-483-3p belong to a new class of natural killer cell functional modulators and strengthen the prominent role of IGF-1 in innate immunity. PMID:23403580

Cytotoxic potential and chromatogram profile of sarang semut tuber (Myrmecodia Pendans Merr. & Perry) after gamma irradiation

International Nuclear Information System (INIS)

Ermin Katrin Winarno; Susanto; Hendig Winarno; Siva Fauziah

2015-01-01

Sarang semut tuber (Myrmecodia pendans Merr. & Perry) has cytotoxic activity. Preservation efforts of sarang semut tuber was performed with gamma irradiation. The research purposed to study the effect of gamma on cytotoxic activity against leukemia L1210 cell lines and chromatogram profiles of sarang semut tuber (Myrmecodia pendans Merr. & Perry). The dried sarang semut tuber were gamma irradiated with a variety of doses of 5; 7.5; 10; and 15 kGy. The experiments were performed with two replicates for each dose. Then samples were macerated with solvent by gradient polarity with n-hexane, ethyl acetate, and ethanol. Extracts were tested against the leukemia L1210 cell lines. From the results obtained showed that the ethanol extract was the most active against leukemia L1210 cell lines (IC50 9.88 μg/ml) compared with n-heksan (IC50 23.44 μg/ml) and ethyl acetate extract (IC50 17.32 μg/ml). Ethanol extracts were fractionated by column chromatography, the result were obtained 7 fractions. Based on the cytotoxic activity test for each fraction, the fraction 1 had the highest activity (IC50 ≤ 3.23 μg/ml). The identifications of ethanol extract and fraction 1 by CLT-densitometry showed that the spots area increased and decreased after gamma irradiation. The chromatogram profile of fraction 1 showed that the major peak area decreased after irradiation. The maximum irradiation dose without damaging the cytotoxic activity of sarang semut tuber againts leukemia L1210 cell lines was 5 kGy. (author)

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

Cytotoxic constituents of ethyl acetate fraction from Dianthus superbus.

Science.gov (United States)

Ding, Chengli; Zhang, Wu; Li, Jie; Lei, Jiachuan; Yu, Jianqing

2013-01-01

The ethyl acetate fraction (EE-DS) from Dianthus superbus was found to possess the cytotoxic activity against cancer cells in previous study. To investigate cytotoxic constituents, the bioassay-guided isolation of compounds from EE-DS was performed. Two dianthramides (1 and 2), three flavonoids (3-5), two coumarins (6 and 7) and three other compounds (8-10) were obtained. Structures of isolated compounds were identified by spectroscopic analysis. Cytotoxicity of the compounds against HepG2 cells was evaluated. Compound 1 showed the strongest cytotoxicity, compounds 10, 4, 3 and 5 had moderate cytotoxicity.

Effects of Cooking and In Vitro Digestion on Antioxidant Properties and Cytotoxicity of the Culinary-Medicinal Mushroom Pleurotus ostreatoroseus (Agaricomycetes).

Science.gov (United States)

Brugnari, Tatiane; da Silva, Pedro Henrique Alves; Contato, Alex Graça; Inácio, Fabíola Dorneles; Nolli, Mariene Marques; Kato, Camila Gabriel; Peralta, Rosane Marina; de Souza, Cristina Giatti Marques

2018-01-01

In this study we evaluated the antioxidant capacity, antimicrobial activity, and cytotoxicity of an aqueous extract of the Pleurotus ostreatoroseus mushroom, which was cooked. Fresh basidiocarps were heated and steamed at 100°C and the resulting aqueous extract was assessed before and after in vitro digestion. Cooking reduced the amounts of phenolic compounds in the extract. The antioxidant activity of the extract was evaluated through the use of 4 methods. The lowest half-maximal effective concentration (EC50) against ABTS radicals was 0.057 ± 0.002 mg/mL for the uncooked basidiocarp extract. Cooking and the digestive process led to decreased activity (P > 0.05) against ABTS and DPPH radicals. A significant increase in chelating activity (P > 0.05) occurred after the basidiocarps were cooked (EC50 = 0.279 ± 0.007 mg/mL). The reducing power did not significantly change among the different extracts. The uncooked basidiocarp extract was cytotoxic to Vero cells. After cooking and subsequent in vitro digestion, the cytotoxicity of the extracts decreased (P < 0.05). Bacillus subtilis, Staphylococcus aureus, and Candida albicans were sensitive to the fresh mushroom extract. The data showed that after being cooked and digested, the P. ostreatoroseus mushroom maintains antioxidant activity and has a low cytotoxic effect.

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.

Quantitative structure-cytotoxicity relationship of phenylpropanoid amides.

Science.gov (United States)

Shimada, Chiyako; Uesawa, Yoshihiro; Ishihara, Mariko; Kagaya, Hajime; Kanamoto, Taisei; Terakubo, Shigemi; Nakashima, Hideki; Takao, Koichi; Saito, Takayuki; Sugita, Yoshiaki; Sakagami, Hiroshi

2014-07-01

A total of 12 phenylpropanoid amides were subjected to quantitative structure-activity relationship (QSAR) analysis, based on their cytotoxicity, tumor selectivity and anti-HIV activity, in order to investigate on their biological activities. Cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines and three human oral normal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor selectivity was evaluated by the ratio of the mean CC50 (50% cytotoxic concentration) against normal oral cells to that against OSCC cell lines. Anti-HIV activity was evaluated by the ratio of CC50 to EC50 (50% cytoprotective concentration from HIV infection). Physicochemical, structural, and quantum-chemical parameters were calculated based on the conformations optimized by the LowModeMD method followed by density functional theory (DFT) method. Twelve phenylpropanoid amides showed moderate cytotoxicity against both normal and OSCC cell lines. N-Caffeoyl derivatives coupled with vanillylamine and tyramine exhibited relatively higher tumor selectivity. Cytotoxicity against normal cells was correlated with descriptors related to electrostatic interaction such as polar surface area and chemical hardness, whereas cytotoxicity against tumor cells correlated with free energy, surface area and ellipticity. The tumor-selective cytotoxicity correlated with molecular size (surface area) and electrostatic interaction (the maximum electrostatic potential). The molecular size, shape and ability for electrostatic interaction are useful parameters for estimating the tumor selectivity of phenylpropanoid amides. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Insights on the antitumor effects of kahweol on human breast cancer: Decreased survival and increased production of reactive oxygen species and cytotoxicity

International Nuclear Information System (INIS)

Cárdenas, Casimiro; Quesada, Ana R.; Medina, Miguel Ángel

2014-01-01

Highlights: • Kahweol inhibits growth and attachment-independent proliferation of tumor cells. • Kahweol induces apoptosis in MDA-MB231 human breast cancer cells. • Kahweol-induced apoptosis involves caspase activation and cytochrome c release. • Kahweol does not protect against hydrogen peroxide cytotoxicity. • Kahweol increases hydrogen peroxide production by human breast cancer cells. - Abstract: The present study aims to identify the modulatory effects of kahweol, an antioxidant diterpene present in coffee beans, on a panel of human tumor cell lines. Kahweol inhibits tumor cell proliferation and clonogenicity and induces apoptosis in several kinds of human tumor cells. In the estrogen receptor-negative MDA-MB231 human breast cancer, the mentioned effects are accompanied by caspases 3/7 and 9 activation and cytochrome c release. On the other hand, kahweol increases the production of reactive oxygen species and their cytotoxicity in human breast cancer cells but not in normal cells. Taken together, our data suggest that kahweol is an antitumor compound with inhibitory effects on tumor cell growth and survival, especially against MDA-MB231 breast cancer cells

Insights on the antitumor effects of kahweol on human breast cancer: Decreased survival and increased production of reactive oxygen species and cytotoxicity

Energy Technology Data Exchange (ETDEWEB)

Cárdenas, Casimiro [Department of Molecular Biology and Biochemistry, Faculty of Sciences, University of Málaga, E-29071 Málaga (Spain); IBIMA (Biomedical Research Institute of Málaga), E-29071 Málaga (Spain); Research Support Central Services (SCAI) of the University of Málaga, E-29071 Málaga (Spain); Quesada, Ana R. [Department of Molecular Biology and Biochemistry, Faculty of Sciences, University of Málaga, E-29071 Málaga (Spain); IBIMA (Biomedical Research Institute of Málaga), E-29071 Málaga (Spain); CIBER de Enfermedades Raras (CIBERER), E-29071 Málaga (Spain); Medina, Miguel Ángel, E-mail: medina@uma.es [Department of Molecular Biology and Biochemistry, Faculty of Sciences, University of Málaga, E-29071 Málaga (Spain); IBIMA (Biomedical Research Institute of Málaga), E-29071 Málaga (Spain); CIBER de Enfermedades Raras (CIBERER), E-29071 Málaga (Spain)

2014-05-09

Highlights: • Kahweol inhibits growth and attachment-independent proliferation of tumor cells. • Kahweol induces apoptosis in MDA-MB231 human breast cancer cells. • Kahweol-induced apoptosis involves caspase activation and cytochrome c release. • Kahweol does not protect against hydrogen peroxide cytotoxicity. • Kahweol increases hydrogen peroxide production by human breast cancer cells. - Abstract: The present study aims to identify the modulatory effects of kahweol, an antioxidant diterpene present in coffee beans, on a panel of human tumor cell lines. Kahweol inhibits tumor cell proliferation and clonogenicity and induces apoptosis in several kinds of human tumor cells. In the estrogen receptor-negative MDA-MB231 human breast cancer, the mentioned effects are accompanied by caspases 3/7 and 9 activation and cytochrome c release. On the other hand, kahweol increases the production of reactive oxygen species and their cytotoxicity in human breast cancer cells but not in normal cells. Taken together, our data suggest that kahweol is an antitumor compound with inhibitory effects on tumor cell growth and survival, especially against MDA-MB231 breast cancer cells.

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)

[Partial purification of peptides present in the Tityus macrochirus (Buthidae) scorpion venom and preliminary assessment of their cytotoxicity].

Science.gov (United States)

Rincón-Cortés, Clara Andrea; Reyes-Montaño, Edgar Antonio; Vega-Castro, Nohora Angélica

2017-06-01

Scorpion venom contains peptides with neurotoxic action primarily active on ion channels in the nervous system of insects and mammals. They are also characterized as cytolytic and anticancer, biological characteristics that have not yet been reported for the Tityus macrochirus venom. To assess if the total T. macrochirus venom and the fraction of partially purified peptides decrease the viability of various tumor-derived cell lines. The scorpion venom was collected by electrical stimulation and, subsequently, subjected to chromatography, electrophoresis, and ultrafiltration with Amicon Ultra 0.5® membranes for the partial identification and purification of its peptides. The cytotoxic activity of the venom and the peptides fraction trials on tumor-derived cell lines were carried out by the MTT method. The T. macrochirus scorpion venom has peptides with molecular weights ranging between 3 and 10 kDa. They were partially purified using the ultrafiltration technique, and assessed by the RP-HPLC method. Cytotoxicity trials with the whole T. macrochirus venom showed a higher viability decrease on the PC3 cell line compared to the other cell lines assessed, while the partially purified peptides decreased the HeLa cell line viability. Peptides in the T. macrochirus scorpion venom showed cytotoxic activity on some tumorderived cell lines. We observed some degree of selectivity against other cell lines assessed.

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

Directory of Open Access Journals (Sweden)

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.

Challenging the roles of CD44 and lipolysis stimulated lipoprotein receptor in conveying Clostridium perfringens iota toxin cytotoxicity in breast cancer.

Science.gov (United States)

Fagan-Solis, Katerina D; Reaves, Denise K; Rangel, M Cristina; Popoff, Michel R; Stiles, Bradley G; Fleming, Jodie M

2014-07-02

Translational exploration of bacterial toxins has come to the forefront of research given their potential as a chemotherapeutic tool. Studies in select tissues have demonstrated that Clostridium perfringens iota toxin binds to CD44 and lipolysis stimulated lipoprotein receptor (LSR) cell-surface proteins. We recently demonstrated that LSR expression correlates with estrogen receptor positive breast cancers and that LSR signaling directs aggressive, tumor-initiating cell behaviors. Herein, we identify the mechanisms of iota toxin cytotoxicity in a tissue-specific, breast cancer model with the ultimate goal of laying the foundation for using iota toxin as a targeted breast cancer therapy. In vitro model systems were used to determine the cytotoxic effect of iota toxin on breast cancer intrinsic subtypes. The use of overexpression and knockdown technologies confirmed the roles of LSR and CD44 in regulating iota toxin endocytosis and induction of cell death. Lastly, cytotoxicity assays were used to demonstrate the effect of iota toxin on a validated set of tamoxifen resistant breast cancer cell lines. Treatment of 14 breast cancer cell lines revealed that LSR+/CD44- lines were highly sensitive, LSR+/CD44+ lines were slightly sensitive, and LSR-/CD44+ lines were resistant to iota cytotoxicity. Reduction in LSR expression resulted in a significant decrease in toxin sensitivity; however, overexpression of CD44 conveyed toxin resistance. CD44 overexpression was correlated with decreased toxin-stimulated lysosome formation and decreased cytosolic levels of iota toxin. These findings indicated that expression of CD44 drives iota toxin resistance through inhibition of endocytosis in breast cancer cells, a role not previously defined for CD44. Moreover, tamoxifen-resistant breast cancer cells exhibited robust expression of LSR and were highly sensitive to iota-induced cytotoxicity. Collectively, these data are the first to show that iota toxin has the potential to be an

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

Cellular uptake and cytotoxicity of positively charged chitosan gold nanoparticles in human lung adenocarcinoma cells

Energy Technology Data Exchange (ETDEWEB)

Choi, Seon Young; Jang, Soo Hwa [Seoul National University, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Institute for Veterinary Science (Korea, Republic of); Park, Jin; Jeong, Saeromi; Park, Jin Ho; Ock, Kwang Su [Soongsil University, Department of Chemistry (Korea, Republic of); Lee, Kangtaek [Yonsei University, Department of Chemical and Biomolecular Engineering (Korea, Republic of); Yang, Sung Ik [Kyung Hee University, College of Environment and Applied Chemistry (Korea, Republic of); Joo, Sang-Woo, E-mail: sjoo@ssu.ac.kr [Soongsil University, Department of Chemistry (Korea, Republic of); Ryu, Pan Dong; Lee, So Yeong, E-mail: leeso@snu.ac.kr [Seoul National University, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Institute for Veterinary Science (Korea, Republic of)

2012-12-15

Cellular uptake, cytotoxicity, and mechanisms of cytotoxicity of the positively charged Au nanoparticles (NPs) were examined in A549 cells, which are one of the most characterized pulmonary cellular systems. Positively charged Au NPs were prepared by chemical reduction using chitosan. The dimension and surface charge of Au NPs were examined by transmission electron microscopy (TEM), dynamic light scattering, and zeta potential measurements. The uptake of Au NPs into A549 cells was also monitored using TEM and dark-field microscopy (DFM) and z-stack confocal microRaman spectroscopy. DFM live cell imaging was also performed to monitor the entry of chitosan Au NPs in real time. The cytotoxic assay, using both methylthiazol tetrazolium and lactate dehydrogenase assays revealed that positively charged Au NPs decreased cell viability. Flow cytometry, DNA fragmentation, real-time PCR, and western blot analysis suggest that positively charged chitosan Au NPs provoke cell damage through both apoptotic and necrotic pathways.

Cellular uptake and cytotoxicity of positively charged chitosan gold nanoparticles in human lung adenocarcinoma cells

International Nuclear Information System (INIS)

Choi, Seon Young; Jang, Soo Hwa; Park, Jin; Jeong, Saeromi; Park, Jin Ho; Ock, Kwang Su; Lee, Kangtaek; Yang, Sung Ik; Joo, Sang-Woo; Ryu, Pan Dong; Lee, So Yeong

2012-01-01

Cellular uptake, cytotoxicity, and mechanisms of cytotoxicity of the positively charged Au nanoparticles (NPs) were examined in A549 cells, which are one of the most characterized pulmonary cellular systems. Positively charged Au NPs were prepared by chemical reduction using chitosan. The dimension and surface charge of Au NPs were examined by transmission electron microscopy (TEM), dynamic light scattering, and zeta potential measurements. The uptake of Au NPs into A549 cells was also monitored using TEM and dark-field microscopy (DFM) and z-stack confocal microRaman spectroscopy. DFM live cell imaging was also performed to monitor the entry of chitosan Au NPs in real time. The cytotoxic assay, using both methylthiazol tetrazolium and lactate dehydrogenase assays revealed that positively charged Au NPs decreased cell viability. Flow cytometry, DNA fragmentation, real-time PCR, and western blot analysis suggest that positively charged chitosan Au NPs provoke cell damage through both apoptotic and necrotic pathways.

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.

Cytotoxicity of ophthalmic solutions with and without preservatives to human corneal endothelial cells, epithelial cells and conjunctival epithelial cells.

Science.gov (United States)

Ayaki, Masahiko; Yaguchi, Shigeo; Iwasawa, Atsuo; Koide, Ryohei

2008-08-01

The cytotoxicity of a range of commercial ophthalmic solutions in the presence and absence of preservatives was assessed in human corneal endothelial cells (HCECs), corneal epithelia and conjunctival epithelia using in vitro techniques. Cell survival was measured using the WST-1 assay for endothelial cells and the MTT assay for epithelial cells. Commercially available timolol, carteolol, cromoglicate, diclofenac, bromfenac and hyaluronic acid ophthalmic solutions were assessed for cytotoxicity in the presence and absence of preservatives. The preservatives benzalkonium, chlorobutanol and polysorbate were also tested. The survival of cells exposed to test ophthalmic solutions was expressed as a percentage of cell survival in the control solution (distilled water added to media) after 48 h exposure. HCEC survival was 20-30% in ophthalmic solutions diluted 10-fold. The survival of HCEC was significantly greater in all solutions in the absence of preservative than in the presence of preservative. The survival of corneal and conjunctival epithelia was consistent with that of HCECs for all test ophthalmic solutions. The preservatives polysorbate and benzalkonium were highly cytotoxic with cell survival decreasing to 20% at the concentration estimated in commercial ophthalmic solutions. By comparison, the survival of cells exposed to chlorobutanol was 80% or greater. The cytotoxicity of ophthalmic solutions to HCEC, corneal epithelia and conjunctival epithelia decreased in the absence of preservative.