Brachyury expression in tailless Molgulid ascidian embryos.

PubMed

Takada, Norio; York, Jonathan; Davis, J Muse; Schumpert, Brenda; Yasuo, Hitoyoshi; Satoh, Nori; Swalla, Billie J

2002-01-01

The T-box transcription factor gene Brachyury is important for the differentiation of notochord in all chordates, including the ascidians Halocynthia roretzi and Ciona intestinalis. We isolated Brachyury from molgulid ascidians, which have evolved tailless larvae multiple times independently, and found the genes appear functional by cDNA sequence analyses. We then compared the expression of Mocu-Bra in tailed Molgula oculata embryos to two tailless species, Molgula occulta (Mocc-Bra) and Molgula tectiformis (Mt-Bra). Here we show that both tailless species express Brachyury in the notochord lineage during embryogenesis. Initial expression of Mocu-Bra is normal in tailed M. oculata embryos; 10 precursor notochord cells divide twice to result in 40 notochord cells that converge and extend to make a notochord down the center of the tail. In contrast, in tailless Molgula occulta, Mocc-Bra expression disappears prematurely, and there is only one round of division, resulting in 20 cells in the final notochord lineage that never converge or extend. In M. occulta x M. oculata hybrid embryos, expression of Mocu-Bra is prolonged, and the embryos form a tail with 20 notochord cells that converge and extend normally. However, in Molgula tectiformis, a different tailless ascidian, Mt-Bra was expressed only in the 10 notochord precursor cells, which never divide, converge, or extend. In summary, neither Brachyury function nor the early establishment of the notochord lineage appears to be impaired in tailless embryos. In light of these results, we are continuing to investigate how and why notochord development is lost in tailless molgulid ascidian embryos.

Vanadium accumulation in carbonaceous rocks: A review of geochemical controls during deposition and diagenesis

USGS Publications Warehouse

Breit, G.N.; Wanty, R.B.

1991-01-01

Published data relevant to the geochemistry of vanadium were used to evaluate processes and conditions that control vanadium accumulation in carbonaceous rocks. Reduction, adsorption, and complexation of dissolved vanadium favor addition of vanadium to sediments rich in organic carbon. Dissolved vanadate (V(V)) species predominate in oxic seawater and are reduced to vanadyl ion (V(IV)) by organic compounds or H2S. Vanadyl ion readily adsorbs to particle surfaces and is added to the sediment as the particles settle. The large vanadium concentrations of rocks deposited in marine as compared to lacustrine environments are the result of the relatively large amount of vanadium provided by circulating ocean water compared to terrestrial runoff. Vanadium-rich carbonaceous rocks typically have high contents of organically bound sulfur and are stratigraphically associated with phosphate-rich units. A correspondence between vanadium content and organically bound sulfur is consistent with high activities of H2S during sediment deposition. Excess H2S exited the sediment into bottom waters and favored reduction of dissolved V(V) to V(IV) or possibly V(III). The stratigraphic association of vanadiferous and phosphatic rocks reflects temporal and spatial shifts in bottom water chemistry from suboxic (phosphate concentrated) to more reducing (euxinic?) conditions that favor vanadium accumulation. During diagenesis some vanadium-organic complexes migrate with petroleum out of carbonaceous rocks, but significant amounts of vanadium are retained in refractory organic matter or clay minerals. As carbon in the rock evolves toward graphite during metamorphism, vanadium is incorporated into silicate minerals. ?? 1991.

cDNA microarray analyses reveal candidate marker genes for the detection of ascidian disease in Korea.

PubMed

Azumi, Kaoru; Usami, Takeshi; Kamimura, Akiko; Sabau, Sorin V; Miki, Yasufumi; Fujie, Manabu; Jung, Sung-Ju; Kitamura, Shin-Ichi; Suzuki, Satoru; Yokosawa, Hideyoshi

2007-12-01

A serious disease of the ascidian Halocynthia roretzi has been spread extensively among Korean aquaculture sites. To reveal the cause of the disease and establish a monitoring system for it, we constructed a cDNA microarray spotted with 2,688 cDNAs derived from H. roretzi hemocyte cDNA libraries to detect genes differentially expressed in hemocytes between diseased and non-diseased ascidians. We detected 21 genes showing increased expression and 16 genes showing decreased expression in hemocytes from diseased ascidians compared with those from non-diseased ascidians. RT-PCR analyses confirmed that the expression levels of genes encoding astacin, lysozyme, ribosomal protein PO, and ubiquitin-ribosomal protein L40e fusion protein were increased in hemocytes from diseased ascidians, while those of genes encoding HSP40, HSP70, fibronectin, carboxypeptidase and lactate dehydrogenase were decreased. These genes were expressed not only in hemocytes but also in various other tissues in ascidians. Furthermore, the expression of glutathione-S transferase omega, which is known to be up-regulated in H. roretzi hemocytes during inflammatory responses, was strongly increased in hemocytes from diseased ascidians. These gene expression profiles suggest that immune and inflammatory reactions occur in the hemocytes of diseased ascidians. These genes will be good markers for detecting and monitoring this disease of ascidians in Korean aquaculture sites.

Vanadium in landscape components of western Transbaikalia

NASA Astrophysics Data System (ADS)

Kashin, V. K.

2017-10-01

Vanadium in soil-forming rocks, soils, and vegetation of forest-steppe, steppe, and dry-steppe landscapes of Transbaikalia has been studied. The mean element contents in rocks and soils are equal to its mean natural abundances (clarke values). The content of vanadium in soils is strictly determined by its content in parent materials; its dependence on the vanadium concentration in plants and on the soil pH and humus is less pronounced. With respect to the coefficient of biological uptake by plants, vanadium is assigned to the group of elements of slight accumulation (0.10-0.33) on mineral soils and of moderate accumulation (1.1-1.5) on peat bog soils. The mean vanadium concentration in steppe, meadow, and cultivated vegetation exceeds the norm for animals by 1.7-2.6 times but does not rich toxic levels. Vanadium uptake by plants is most intensive in meadow cenoses and is less intensive in dry-steppe cenoses.

Time course for tail regression during metamorphosis of the ascidian Ciona intestinalis.

PubMed

Matsunobu, Shohei; Sasakura, Yasunori

2015-09-01

In most ascidians, the tadpole-like swimming larvae dramatically change their body-plans during metamorphosis and develop into sessile adults. The mechanisms of ascidian metamorphosis have been researched and debated for many years. Until now information on the detailed time course of the initiation and completion of each metamorphic event has not been described. One dramatic and important event in ascidian metamorphosis is tail regression, in which ascidian larvae lose their tails to adjust themselves to sessile life. In the present study, we measured the time associated with tail regression in the ascidian Ciona intestinalis. Larvae are thought to acquire competency for each metamorphic event in certain developmental periods. We show that the timing with which the competence for tail regression is acquired is determined by the time since hatching, and this timing is not affected by the timing of post-hatching events such as adhesion. Because larvae need to adhere to substrates with their papillae to induce tail regression, we measured the duration for which larvae need to remain adhered in order to initiate tail regression and the time needed for the tail to regress. Larvae acquire the ability to adhere to substrates before they acquire tail regression competence. We found that when larvae adhered before they acquired tail regression competence, they were able to remember the experience of adhesion until they acquired the ability to undergo tail regression. The time course of the events associated with tail regression provides a valuable reference, upon which the cellular and molecular mechanisms of ascidian metamorphosis can be elucidated. Copyright © 2015 Elsevier Inc. All rights reserved.

Enrichment, Distribution of Vanadium-Containing Protein in Vanadium-Enriched Sea Cucumber Apostichopus japonicus and the Ameliorative Effect on Insulin Resistance.

PubMed

Liu, Yanjun; Zhou, Qingxin; Zhao, Yanlei; Wang, Yiming; Wang, Yuming; Wang, Jingfeng; Xu, Jie; Xue, Changhu

2016-05-01

Sea cucumbers are a potential source of natural organic vanadium that may improve insulin resistance. In this work, vanadium was accumulated rapidly in blood, body wall, and intestine by sea cucumber Apostichopus japonicus. Furthermore, water-soluble vanadium-containing proteins, the main form of the organic vanadium, were tentatively accumulated and isolated by a bioaccumulation experiment. It was also designed to evaluate the beneficial effect of vanadium-containing proteins (VCPs) from sea cucumber rich in vanadium on the development of hyperglycemia and insulin resistance in C57BL/6J mice fed with a high-fat high-sucrose diet (HFSD). HFSD mice treated with VCPs significantly decreased fasting blood glucose, serum insulin, and HOMA-IR values as compared to HFSD mice, respectively. Serum adiponectin, resistin, TNF-α, and leptin levels in insulin-resistant mice were dramatically reduced by a VCP supplement. These results show an ameliorative effect on insulin resistance by treatment with VCPs. Such compound seems to be a valuable therapy to achieve and/or maintain glycemic control and therapeutic agents in the treatment arsenal for insulin resistance and type 2 diabetes.

Monoaminergic modulation of photoreception in ascidian: evidence for a proto-hypothalamo-retinal territory

PubMed Central

2012-01-01

Background The retina of craniates/vertebrates has been proposed to derive from a photoreceptor prosencephalic territory in ancestral chordates, but the evolutionary origin of the different cell types making the retina is disputed. Except for photoreceptors, the existence of homologs of retinal cells remains uncertain outside vertebrates. Methods The expression of genes expressed in the sensory vesicle of the ascidian Ciona intestinalis including those encoding components of the monoaminergic neurotransmission systems, was analyzed by in situ hybridization or in vivo transfection of the corresponding regulatory elements driving fluorescent reporters. Modulation of photic responses by monoamines was studied by electrophysiology combined with pharmacological treatments. Results We show that many molecular characteristics of dopamine-synthesizing cells located in the vicinity of photoreceptors in the sensory vesicle of the ascidian Ciona intestinalis are similar to those of amacrine dopamine cells of the vertebrate retina. The ascidian dopamine cells share with vertebrate amacrine cells the expression of the key-transcription factor Ptf1a, as well as that of dopamine-synthesizing enzymes. Surprisingly, the ascidian dopamine cells accumulate serotonin via a functional serotonin transporter, as some amacrine cells also do. Moreover, dopamine cells located in the vicinity of the photoreceptors modulate the light-off induced swimming behavior of ascidian larvae by acting on alpha2-like receptors, instead of dopamine receptors, supporting a role in the modulation of the photic response. These cells are located in a territory of the ascidian sensory vesicle expressing genes found both in the retina and the hypothalamus of vertebrates (six3/6, Rx, meis, pax6, visual cycle proteins). Conclusion We propose that the dopamine cells of the ascidian larva derive from an ancestral multifunctional cell population located in the periventricular, photoreceptive field of the anterior

Geochemical controls on vanadium accumulation in fossil fuels

USGS Publications Warehouse

Breit, G.N.; Wanty, R.B.

1989-01-01

High vanadium contents in petroleum and other fossil fuels have been attributed to organic-matter type, organisms, volcanic emanations, diffusion of sea water, and epigenetic enrichment. However, these factors are inadequate to account for the high abundance of vanadium in some fossil fuels and the paucity in others. By examining vanadium deposits in sedimentary rocks with sparse organic matter, constraints are placed on processes controlling vanadium accumulation in organic-rich sediments. Vanadium, as vanadate (V(V)), entered some depositional basins in oxidizing waters from dry, subaerial environments. Upon contact with organic matter in anoxic waters, V(V) is reduced to vanadyl (V(IV)), which can be removed from the water column by adsorption. H2S reduces V(IV) to V(III), which hydrolyzes and precipitates. The lack of V(III) in petroleum suggests that reduction of V(IV) to V(III) is inhibited by organic complexes. In the absence of strong complexing agents, V(III) forms and is incorporated in clay minerals.

Geochemical controls of vanadium accumulation in fossil fuels

USGS Publications Warehouse

Breit, G.N.; Wanty, R.B.

1989-01-01

High vanadium contents in petroleum and other fossil fuels have been attributed to organic-matter type, organisms, volcanic emanations, diffusion of sea water, and epigenetic enrichment. However, these factors are inadequate to account for the high abundance of vanadium in some fossil fuels and the paucity in others. By examining vanadium deposits in sedimentary rocks with sparse organic matter, constraints are placed on processes controlling vanadium accumulation in organic-rich sediments. Vanadium, as vanadate (V(V)), entered some depositional basins in oxidizing waters from dry, subaerial environments. Upon contact with organic matter in anoxic waters, V(V) is reduced to vanadyl (V(IV)), which can be removed from the water column by adsorption. H2S reduces V(IV) to V(III), which hydrolyzes and precipitates. The lack of V(III) in petroleum suggests that reduction of V(IV) to V(III) is inhibited by organic complexes. In the absence of strong complexing agents, V(III) forms and is incorporated in clay minerals.

Genetic pathways for differentiation of the peripheral nervous system in ascidians

PubMed Central

Waki, Kana; Imai, Kaoru S.; Satou, Yutaka

2015-01-01

Ascidians belong to tunicates, the sister group of vertebrates. Peripheral nervous systems (PNSs) including epidermal sensory neurons (ESNs) in the trunk and dorsal tail regions of ascidian larvae are derived from cells adjacent to the neural plate, as in vertebrates. On the other hand, peripheral ESNs in the ventral tail region are derived from the ventral ectoderm under the control of BMP signalling, reminiscent of sensory neurons of amphioxus and protostomes. In this study, we show that two distinct mechanisms activate a common gene circuit consisting of Msx, Ascl.b, Tox, Delta.b and Pou4 in the dorsal and ventral regions to differentiate ESNs. Our results suggest that ventral ESNs of the ascidian larva are not directly homologous to vertebrate PNSs. The dorsal ESNs might have arisen via co-option of the original PNS gene circuit to the neural plate border in an ancestral chordate. PMID:26515371

Polarity of the ascidian egg cortex and relocalization of cER and mRNAs in the early embryo.

PubMed

Prodon, François; Dru, Philippe; Roegiers, Fabrice; Sardet, Christian

2005-06-01

The mature ascidian oocyte is a large cell containing cytoplasmic and cortical domains polarized along a primary animal-vegetal (a-v) axis. The oocyte cortex is characterized by a gradient distribution of a submembrane monolayer of cortical rough endoplasmic reticulum (cER) and associated maternal postplasmic/PEM mRNAs (cER-mRNA domain). Between fertilization and first cleavage, this cER-mRNA domain is first concentrated vegetally and then relocated towards the posterior pole via microfilament-driven cortical contractions and spermaster-microtubule-driven translocations. The cER-mRNA domain further concentrates in a macroscopic cortical structure called the centrosome attracting body (CAB), which mediates a series of asymmetric divisions starting at the eight-cell stage. This results in the segregation of determinant mRNAs and their products in posterior cells of the embryo precursors of the muscle and germ line. Using two species of ascidians (Ciona intestinalis and Phallusia mammillata), we have pursued and amplified the work initiated in Halocynthia roretzi. We have analysed the cortical reorganizations in whole cells and in cortical fragments isolated from oocytes and from synchronously developing zygotes and embryos. After fertilization, we observe that a cortical patch rich in microfilaments encircles the cER-mRNA domain, concentrated into a cortical cap at the vegetal/contraction pole (indicating the future dorsal pole). Isolated cortices also retain microtubule asters rich in cER (indicating the future posterior pole). Before mitosis, parts of the cER-mRNA domain are detected, together with short microtubules, in isolated posterior (but not anterior) cortices. At the eight-cell stage, the posteriorly located cER-mRNA domain undergoes a cell-cycle-dependant compaction into the CAB. The CAB with embedded centrosomal microtubules can be isolated with cortical fragments from eight-cell-stage embryos. These and previous observations indicate that cytoskeleton

Diversity of pufM genes, involved in aerobic anoxygenic photosynthesis, in the bacterial communities associated with colonial ascidians.

PubMed

Martínez-García, Manuel; Díaz-Valdés, Marta; Antón, Josefa

2010-03-01

Ascidians are invertebrate filter feeders widely distributed in benthic marine environments. A total of 14 different ascidian species were collected from the Western Mediterranean and their bacterial communities were analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene. Results showed that ascidian tissues harbored Bacteria belonging to Gamma- and Alphaproteobacteria classes, some of them phylogenetically related to known aerobic anoxygenic phototrophs (AAPs), such as Roseobacter sp. In addition, hierarchical cluster analysis of DGGE patterns showed a large variability in the bacterial diversity among the different ascidians analyzed, which indicates that they would harbor different bacterial communities. Furthermore, pufM genes, involved in aerobic anoxygenic photosynthesis in marine and freshwater systems, were widely detected within the ascidians analyzed, because nine out of 14 species had pufM genes inside their tissues. The pufM gene was only detected in those specimens that inhabited shallow waters (<77 m of depth). Most pufM gene sequences were very closely related to that of uncultured marine bacteria. Thus, our results suggest that the association of ascidians with bacteria related to AAPs could be a general phenomenon and that ascidian-associated microbiota could use the light that penetrates through the tunic tissue as an energy source.

Stochastic model of cell rearrangements in convergent extension of ascidian notochord

NASA Astrophysics Data System (ADS)

Lubkin, Sharon; Backes, Tracy; Latterman, Russell; Small, Stephen

2007-03-01

We present a discrete stochastic cell based model of convergent extension of the ascidian notochord. Our work derives from research that clarifies the coupling of invagination and convergent extension in ascidian notochord morphogenesis (Odell and Munro, 2002). We have tested the roles of cell-cell adhesion, cell-extracellular matrix adhesion, random motion, and extension of individual cells, as well as the presence or absence of various tissue types, and determined which factors are necessary and/or sufficient for convergent extension.

Ascidians as excellent chordate models for studying the development of the nervous system during embryogenesis and metamorphosis.

PubMed

Sasakura, Yasunori; Mita, Kaoru; Ogura, Yosuke; Horie, Takeo

2012-04-01

The swimming larvae of the chordate ascidians possess a dorsal hollowed central nervous system (CNS), which is homologous to that of vertebrates. Despite the homology, the ascidian CNS consists of a countable number of cells. The simple nervous system of ascidians provides an excellent experimental system to study the developmental mechanisms of the chordate nervous system. The neural fate of the cells consisting of the ascidian CNS is determined in both autonomous and non-autonomous fashion during the cleavage stage. The ascidian neural plate performs the morphogenetic movement of neural tube closure that resembles that in vertebrate neural tube formation. Following neurulation, the CNS is separated into five distinct regions, whose homology with the regions of vertebrate CNS has been discussed. Following their larval stage, ascidians undergo a metamorphosis and become sessile adults. The metamorphosis is completed quickly, and therefore the metamorphosis of ascidians is a good experimental system to observe the reorganization of the CNS during metamorphosis. A recent study has shown that the major parts of the larval CNS remain after the metamorphosis to form the adult CNS. In contrast to such a conserved manner of CNS reorganization, most larval neurons disappear during metamorphosis. The larval glial cells in the CNS are the major source for the formation of the adult CNS, and some of the glial cells produce adult neurons. © 2012 The Authors Development, Growth & Differentiation © 2012 Japanese Society of Developmental Biologists.

Bio-invasive ascidians in Ireland: A threat for the shellfish industry but also a source of high added value products.

PubMed

Palanisamy, Satheesh Kumar; Thomas, Olivier P; P McCormack, Grace

2018-01-01

In October 2016, a rapid assessment survey of ascidian species was conducted in shellfish farms at Killary Fjord, in the west of Ireland. Two non-indigenous solitary ascidians Ascidiella aspersa and Corella eumoyta were recorded for the first time in shellfish farms at this location. Both invasive ascidians have the potential to greatly reduce mussel production in Killary Fjord by competing with shellfish for food and habitat. Their high abundance also causes an increase in maintenance costs leading to economic losses for aquaculture farmers. Prompted by our finding of two invasive ascidians in Killary Fjord, we provide a brief review of the ecological role of ascidians and the potential of harnessing biomass from such invasive species for the production of high added value marine natural products.

A Contemporary Treatment Approach to Both Diabetes and Depression by Cordyceps sinensis, Rich in Vanadium

PubMed Central

Guo, Jian-You; Han, Chun-Chao

2010-01-01

Diabetes mellitus is accompanied by hormonal and neurochemical changes that can be associated with anxiety and depression. Both diabetes and depression negatively interact, in that depression leads to poor metabolic control and hyperglycemia exacerbates depression. We hypothesize one novel vanadium complex of vanadium-enriched Cordyceps sinensis (VECS), which is beneficial in preventing depression in diabetes, and influences the long-term course of glycemic control. Vanadium compounds have the ability to imitate the action of insulin, and this mimicry may have further favorable effects on the level of treatment satisfaction and mood. C. sinensis has an antidepressant-like activity, and attenuates the diabetes-induced increase in blood glucose concentrations. We suggest that the VECS may be a potential strategy for contemporary treatment of depression and diabetes through the co-effect of C. sinensis and vanadium. The validity of the hypothesis can most simply be tested by examining blood glucose levels, and swimming and climbing behavior in streptozotocin-induced hyperglycemic rats. PMID:19948751

Concentration Dependence of VO2+ Crossover of Nafion for Vanadium Redox Flow Batteries

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

Lawton, Jamie; Jones, Amanda; Zawodzinski, Thomas A

2013-01-01

The VO2+ crossover, or permeability, through Nafion in a vanadium redox flow battery (VRFB) was monitored as a function of sulfuric acid concentration and VO2+ concentration. A vanadium rich solution was flowed on one side of the membrane through a flow field while symmetrically on the other side a blank or vanadium deficit solution was flowed. The blank solution was flowed through an electron paramagnetic resonance (EPR) cavity and the VO2+ concentration was determined from the intensity of the EPR signal. Concentration values were fit using a solution of Fick s law that allows for the effect of concentration changemore » on the vanadium rich side. The fits resulted in permeability values of VO2+ ions across the membrane. Viscosity measurements of many VO2+ and H2SO4 solutions were made at 30 60 C. These viscosity values were then used to determine the effect of the viscosity of the flowing solution on the permeability of the ion. 2013 The Electrochemical Society. [DOI: 10.1149/2.004306jes] All rights reserved.« less

Microenvironment and phylogenetic diversity of Prochloron inhabiting the surface of crustose didemnid ascidians.

PubMed

Nielsen, Daniel A; Pernice, Mathieu; Schliep, Martin; Sablok, Gaurav; Jeffries, Thomas C; Kühl, Michael; Wangpraseurt, Daniel; Ralph, Peter J; Larkum, Anthony W D

2015-10-01

The cyanobacterium Prochloron didemni is primarily found in symbiotic relationships with various marine hosts such as ascidians and sponges. Prochloron remains to be successfully cultivated outside of its host, which reflects a lack of knowledge of its unique ecophysiological requirements. We investigated the microenvironment and diversity of Prochloron inhabiting the upper, exposed surface of didemnid ascidians, providing the first insights into this microhabitat. The pH and O2 concentration in this Prochloron biofilm changes dynamically with irradiance, where photosynthetic activity measurements showed low light adaptation (Ek ∼ 80 ± 7 μmol photons m(-2) s(-1)) but high light tolerance. Surface Prochloron cells exhibited a different fine structure to Prochloron cells from cloacal cavities in other ascidians, the principle difference being a central area of many vacuoles dissected by single thylakoids in the surface Prochloron. Cyanobacterial 16S rDNA pyro-sequencing of the biofilm community on four ascidians resulted in 433 operational taxonomic units (OTUs) where on average -85% (65-99%) of all sequence reads, represented by 136 OTUs, were identified as Prochloron via blast search. All of the major Prochloron-OTUs clustered into independent, highly supported phylotypes separate from sequences reported for internal Prochloron, suggesting a hitherto unexplored genetic variability among Prochloron colonizing the outer surface of didemnids. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Nonreproductive role of gonadotropin-releasing hormone in the control of ascidian metamorphosis.

PubMed

Kamiya, Chisato; Ohta, Naoyuki; Ogura, Yosuke; Yoshida, Keita; Horie, Takeo; Kusakabe, Takehiro G; Satake, Honoo; Sasakura, Yasunori

2014-12-01

Gonadotropin-releasing hormones (GnRHs) are neuropeptides that play central roles in the reproduction of vertebrates. In the ascidian Ciona intestinalis, GnRHs and their receptors are expressed in the nervous systems at the larval stage, when animals are not yet capable of reproduction, suggesting that the hormones have non-reproductive roles. We showed that GnRHs in Ciona are involved in the animal's metamorphosis by regulating tail absorption and adult organ growth. Absorption of the larval tail and growth of the adult organs are two major events in the metamorphosis of ascidians. When larvae were treated with GnRHs, they completed tail absorption more frequently than control larvae. cAMP was suggested to be a second messenger for the induction of tail absorption by GnRHs. tGnRH-3 and tGnRH-5 (the "t" indicates "tunicate") inhibited the growth of adult organs by arresting cell cycle progression in parallel with the promotion of tail absorption. This study provides new insights into the molecular mechanisms of ascidian metamorphosis conducted by non-reproductive GnRHs. © 2014 Wiley Periodicals, Inc.

The Mediterranean non-indigenous ascidian Polyandrocarpa zorritensis: Microbiological accumulation capability and environmental implications.

PubMed

Stabili, Loredana; Licciano, Margherita; Longo, Caterina; Lezzi, Marco; Giangrande, Adriana

2015-12-15

We investigated the bacterial accumulation and digestion capability of Polyandrocarpa zorritensis, a non-indigenous colonial ascidian originally described in Peru and later found in the Mediterranean. Microbiological analyses were carried out on homogenates from "unstarved" and "starved" ascidians and seawater from the same sampling site (Adriatic Sea, Italy). Culturable heterotrophic bacteria (22 °C), total culturable bacteria (37 °C) and vibrios abundances were determined on Marine Agar 2216, Plate Count Agar and TCBS Agar, respectively. Microbial pollution indicators were measured by the most probable number method. All the examined microbiological groups were accumulated by ascidians but differently digested. An interesting outcome is the capability of P. zorritensis to digest allochthonous microorganisms such as coliforms as well as culturable bacteria at 37 °C, counteracting the effects of microbial pollution. Thus, the potential exploitation of these filter feeders to restore polluted seawater should be taken into consideration in the management of this alien species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nitric oxide production by hemocytes of the ascidian Styela plicata.

PubMed

de Barros, Cintia Monteiro; de Carvalho, Danielle Ronald; Andrade, Leonardo R; Pavão, Mauro Sérgio G; Allodi, Silvana

2009-10-01

Ascidian hemolymph contains various types of blood cells (hemocytes), which are believed to be involved in defense mechanisms. We have studied nitric-oxide (NO) synthase activity in hemocytes of the ascidian Styela plicata after exposure to lipopolysaccharide (LPS). To investigate which cell types are involved in NO production, we first identified, by electron microscopy, the types of hemocytes previously described, mainly by light microscopy, by others. Five types of blood cells could be recognized in the hemolymph: granulocytes, hemoblasts, lymphocyte-like cells, morula cells, and pigment cells. The lymphocyte-like cells produced the most NO. In agreement with studies of other invertebrates, nitrite generation did not change after LPS stimulation in assays in vitro, under either different concentrations of LPS or different time periods. Therefore, we performed an in vivo assay by injecting a known quantity of Escherichia coli into the tunic of the ascidians in order to investigate possible differences in NO levels. No increase of NO occurred accompanying the inflammatory reaction suggesting that another molecule in the pathway was involved. We found that nuclear factor kappaB (NFkappaB) was activated. Since NFkappaB is involved in the production of many substances related to immune responses, additional molecules might also be generated in response to E. coli infection. These observations may improve our understanding of the reaction of animals to eutrophic conditions.

THE COLORIMETRIC DETERMINATION OF VANADIUM IN NIOBIUM-VANADIUM ALLOYS

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

Articolo, O.J.

1959-06-26

A procedure is described for the analysis of vanadium in niobium-- vanadium alloys in the range >0.1% vanadium with an accuracy of better than 3%. The method was applied to the analysis of niobium alloys in which the nominal per cent vanadium varied between 0.3 to 4.6%. The sample is dissolved in a mixture of nitric and hydrofluoric acid and then evaporated to fumes with sulfuric acid. The niobium is hydrolyzed with sulfurous acid and separated from the vanadium by filtration. Hydrogen peroxide is added to the filtrate to form a reddish brown complex with the vanadium. The optical densitymore » of the resulting solution is obtained at 450 m mu on a model B Beckman spectrophotometer. (auth)« less

Vanadium Transitions in the Spectrum of Arcturus

NASA Astrophysics Data System (ADS)

Wood, M. P.; Sneden, C.; Lawler, J. E.; Den Hartog, E. A.; Cowan, J. J.; Nave, G.

2018-02-01

We derive a new abundance for vanadium in the bright, mildly metal-poor red giant Arcturus. This star has an excellent high-resolution spectral atlas and well-understood atmospheric parameters, and it displays a rich set of neutral vanadium lines that are available for abundance extraction. We employ a newly recorded set of laboratory FTS spectra to investigate any potential discrepancies in previously reported V I log(gf) values near 900 nm. These new spectra support our earlier laboratory transition data and the calibration method utilized in that study. We then perform a synthetic spectrum analysis of weak V I features in Arcturus, deriving log ε(V) = 3.54 ± 0.01 (σ = 0.04) from 55 lines. There are no significant abundance trends with wavelength, line strength, or lower excitation energy.

Habitat niche breadth predicts invasiveness in solitary ascidians.

PubMed

Granot, Itai; Shenkar, Noa; Belmaker, Jonathan

2017-10-01

A major focus of invasion biology is understanding the traits associated with introduction success. Most studies assess these traits in the invaded region, while only few compare nonindigenous species to the pool of potential invaders in their native region. We focused on the niche breadth hypothesis , commonly evoked but seldom tested, which states that generalist species are more likely to become introduced as they are capable of thriving under a wide set of conditions. Based on the massive introduction of tropical species into the Mediterranean via the Suez Canal (Lessepsian migration), we defined ascidians in the Red Sea as the pool of potential invaders. We constructed unique settlement plates, each representing six different niches, to assess ascidian niche breadth, and deployed them in similar habitats in the native and invaded regions. For each species found on plates, we evaluated its abundance, relative abundance across successional stages, and niche breadth, and then compared (1) species in the Red Sea known to have been introduced into the Mediterranean (Lessepsian species) and those not known from the Mediterranean (non-Lessepsian); and (2) nonindigenous and indigenous species in the Mediterranean. Lessepsian species identified on plates in the Red Sea demonstrated wider niche breadth than non-Lessepsian species, supporting the niche breadth hypothesis within the native region. No differences were found between Lessepsian and non-Lessepsian species in species abundance and successional stages. In the Mediterranean, nonindigenous species numerically dominated the settlement plates. This precluded robust comparisons of niche breadth between nonindigenous and indigenous species in the invaded region. In conclusion, using Red Sea ascidians as the pool of potential invaders, we found clear evidence supporting the niche breadth hypothesis in the native region. We suggest that such patterns may often be obscured when conducting trait-based studies in the

Chondroitin 6-O-sulfotransferases are required for morphogenesis of the notochord in the ascidian embryo.

PubMed

Nakamura, Jun; Yoshida, Keita; Sasakura, Yasunori; Fujiwara, Shigeki

2014-12-01

Chondroitin sulfate (CS) is a sulfated polysaccharide chain that binds to various core proteins to form proteoglycans. The amount and position of sulfate groups in CS are variable among different tissues, and are determined by specific sulfotransferases. Although the ascidians are the closest relatives of vertebrates, the functions of their sulfotransferases have not been studied. The genome of the ascidian Ciona intestinalis contains eight genes encoding proteins similar to chondroitin 6-O-sulfotransferases (C6STs), which appear to have independently diverged in the ascidian lineage during evolution. Among them, Ci-C6ST-like1 and Ci-C6ST-like7 were predominantly expressed in the developing notochord. In addition, they were weakly expressed in the neural tube. The disruption of either one of them affected the convergent extension movement of notochordal cells. Presumptive notochord cells coming from both sides of the embryo did not intercalate. The results suggest that both of them are necessary. In some cases, the anterior neural tube failed to close. Forced expression of Ci-C6ST-like1 or Ci-C6ST-like7 in the notochord restored the normal intercalation of notochordal cells, indicating that the effects of morpholino oligos are specific. Ci-C6ST-like1 and Ci-C6ST-like7 are required for the morphogenesis of the notochord in the ascidian embryo. © 2014 Wiley Periodicals, Inc.

Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role

PubMed Central

Núñez-Pons, Laura; Carbone, Marianna; Vázquez, Jennifer; Rodríguez, Jaime; Nieto, Rosa María; Varela, María Mercedes; Gavagnin, Margherita; Avila, Conxita

2012-01-01

Ascidians have developed multiple defensive strategies mostly related to physical, nutritional or chemical properties of the tunic. One of such is chemical defense based on secondary metabolites. We analyzed a series of colonial Antarctic ascidians from deep-water collections belonging to the genera Aplidium and Synoicum to evaluate the incidence of organic deterrents and their variability. The ether fractions from 15 samples including specimens of the species A. falklandicum, A. fuegiense, A. meridianum, A. millari and S. adareanum were subjected to feeding assays towards two relevant sympatric predators: the starfish Odontaster validus, and the amphipod Cheirimedon femoratus. All samples revealed repellency. Nonetheless, some colonies concentrated defensive chemicals in internal body-regions rather than in the tunic. Four ascidian-derived meroterpenoids, rossinones B and the three derivatives 2,3-epoxy-rossinone B, 3-epi-rossinone B, 5,6-epoxy-rossinone B, and the indole alkaloids meridianins A–G, along with other minoritary meridianin compounds were isolated from several samples. Some purified metabolites were tested in feeding assays exhibiting potent unpalatabilities, thus revealing their role in predation avoidance. Ascidian extracts and purified compound-fractions were further assessed in antibacterial tests against a marine Antarctic bacterium. Only the meridianins showed inhibition activity, demonstrating a multifunctional defensive role. According to their occurrence in nature and within our colonial specimens, the possible origin of both types of metabolites is discussed. PMID:23015772

Role of the FGF and MEK signaling pathway in the ascidian embryo.

PubMed

Kim, G J; Nishida, H

2001-10-01

In the ascidian embryo, a fibroblast growth factor (FGF)-like signal from presumptive endoderm blastomeres between the 32-cell and early 64-cell stages induces the formation of notochord and mesenchyme cells. However, it has not been known whether endogenous FGF signaling is involved in the process. Here it is shown that 64-cell embryos exhibit a marked increase in endogenous extracellular signal-regulated kinase (ERK/MAPK) activity. The increase in ERK activity was reduced by treatment with an FGF receptor 1 inhibitor, SU5402, and a MEK (ERK kinase/MAPKK) inhibitor, U0126. Both drugs blocked the formation of notochord and mesenchyme when embryos were treated at the 32-cell stage, but not at the 2- or 110-cell stages. The dominant-negative form of Ras also suppressed notochord and mesenchyme formation. Both inhibitors suppressed induction by exogenous basic FGF. These results suggest that the FGF signaling cascade is indeed necessary for the formation of notochord and mesenchyme cells during ascidian embryogenesis. It is also shown that FGF signaling is required for formation of the secondary notochord, secondary muscle and neural tissues, and at least ERK activity is necessary for the formation of trunk lateral cells and posterior endoderm. Therefore, FGF and MEK signaling are required for the formation of various tissues in the ascidian embryo.

Vanadium Electrolyte Studies for the Vanadium Redox Battery-A Review.

PubMed

Skyllas-Kazacos, Maria; Cao, Liuyue; Kazacos, Michael; Kausar, Nadeem; Mousa, Asem

2016-07-07

The electrolyte is one of the most important components of the vanadium redox flow battery and its properties will affect cell performance and behavior in addition to the overall battery cost. Vanadium exists in several oxidation states with significantly different half-cell potentials that can produce practical cell voltages. It is thus possible to use the same element in both half-cells and thereby eliminate problems of cross-contamination inherent in all other flow battery chemistries. Electrolyte properties vary with supporting electrolyte composition, state-of-charge, and temperature and this will impact on the characteristics, behavior, and performance of the vanadium battery in practical applications. This Review provides a broad overview of the physical properties and characteristics of the vanadium battery electrolyte under different conditions, together with a description of some of the processing methods that have been developed to produce vanadium electrolytes for vanadium redox flow battery applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Life in cellulose houses: Symbiotic bacterial biosynthesis of ascidian drugs and drug leads

PubMed Central

Schmidt, Eric W.; Donia, Mohamed S.

2010-01-01

Ascidians (tunicates; sea squirts) are sources of diverse, bioactive natural products, one of which is an approved drug and many of which are potent drug leads. It has been shown that symbiotic bacteria living with ascidians produce some of the bioactive compounds isolated from whole animals, and indirect evidence strongly implicates symbiotic bacteria in the synthesis of many others. However, for the majority the producing organism has not been identified. In cases where a symbiotic origin has been definitively assigned, the resulting data lead to improved paths to drug discovery and development from marine animals. This review traces evidence for symbiotic production where such evidence exists and describes the strengths and limitations of that evidence. PMID:21050742

Superior Electrocatalytic Activity of a Robust Carbon-Felt Electrode with Oxygen-Rich Phosphate Groups for All-Vanadium Redox Flow Batteries.

PubMed

Kim, Ki Jae; Lee, Heon Seong; Kim, Jeonghun; Park, Min-Sik; Kim, Jung Ho; Kim, Young-Jun; Skyllas-Kazacos, Maria

2016-06-08

A newly prepared type of carbon felt with oxygen-rich phosphate groups is proposed as a promising electrode with good stability for all-vanadium redox flow batteries (VRFBs). Through direct surface modification with ammonium hexafluorophosphate (NH4 PF6 ), phosphorus can be successfully incorporated onto the surface of the carbon felt by forming phosphate functional groups with -OH chemical moieties that exhibit good hydrophilicity. The electrochemical reactivity of the carbon felt toward the redox reactions of VO(2+) /VO2 (+) (in the catholyte) and V(3+) /V(2+) (in the anolyte) can be effectively improved owing to the superior catalytic effects of the oxygen-rich phosphate groups. Furthermore, undesirable hydrogen evolution can be suppressed by minimizing the overpotential for the V(3+) /V(2+) redox reaction in the anolyte of the VRFB. Cell-cycling tests with the catalyzed electrodes show improved energy efficiencies of 88.2 and 87.2 % in the 1(st) and 20(th)  cycles compared with 83.0 and 81.1 %, respectively, for the pristine electrodes at a constant current density of 32 mA cm(-2) . These improvements are mainly attributed to the faster charge transfer allowed by the integration of the oxygen-rich phosphate groups on the carbon-felt electrode. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Filtering activity on a pure culture of Vibrio alginolyticus by the solitary ascidian Styela plicata and the colonial ascidian Polyandrocarpa zorritensis: a potential service to improve microbiological seawater quality economically.

PubMed

Stabili, Loredana; Licciano, Margherita; Gravina, Maria Flavia; Giangrande, Adriana

2016-12-15

We investigated and compared, by laboratory experiments, the filter-feeding activity on bacteria by the solitary ascidian Styela plicata and the colonial ascidian Polyandrocarpa zorritensis. Clearance rates and retention efficiencies were estimated by using, as only food source, the bacterial species Vibrio alginolyticus selected on account of its importance in aquaculture pathogenicity. The Cmax was 1.4±0.17Lh -1 g -1 DW for S. plicata and 1.745Lh -1 g -1 DW for P. zorritensis. The highest retention efficiency was 41% corresponding to a removed bacterial biomass of 16.34+1.71 μgCL -1 g -1 DW for P. zorritensis and 81% corresponding to a bacterial biomass of 32.28+2.15 μgCL -1 g -1 DW for S. plicata. Styela plicata resulted higher efficient than P. zorritensis in removing V. alginolyticus from seawater in experimental tanks, thus representing a more suitable biofilter to restore the quality of microbiologically contaminated waters including those where aquaculture is practiced. Present laboratory experiments represent the first contribution to the comparison of the filtration activity of the two ascidians, as well as to characterize the filtration process on bacterioplankton and pone the basis for future field works aimed to restore bacteriological polluted seawater. Copyright © 2016 Elsevier B.V. All rights reserved.

Marine Ecological Index Survey of San Diego Bay

DTIC Science & Technology

2013-03-01

Ascidia zara Thermal DO Chordata Botrylloides violaceus Thermal DO Chordata Diplosoma listerianum Thermal DO Annelida Brania complex Thermal DO Annelida...x x Ascidia Zara x? x? x x Ascidia sp x? x x x x Styela canopus x x x x x Styela clava x x x x x Styela plicata x x x x x Polyandrocarpa zorritensis...Estuarine Marine Seasonally Hypersaline Thermal Native Pre ID Region(a) Aplidium californicum x x x Ascidia ceratodes x x Ascidia zara x Estuarine

Rotating spiral waves in fertilized ascidian eggs.

PubMed

Ballarò, Benedetto; Reas, Pier Giorgio

2002-01-01

Excitable systems modelled by reaction-diffusion equation may be expected to produce quite complex spatial patterns. Winfree [1974] demonstrated experimentally, in the Belousov-Zhabotinskii reaction, the existence of particular waves called rotating spiral waves. Later Keener and Tyson [1986] presented a thorough analysis of these waves in excitable systems. Spiral waves can also be observed in brain tissue (Shibata and Bures [1974]), while it seems that the precursor to cardiac fibrillation is the appearance of rotating waves of electrical impulses (Winfree [1983]). In this work we suppose the appearance of Ca++ spiral waves in the vegetal pole of ascidian egg cells after the first ooplasmic segregation. Previously we observed that (Ballarò and Reas [2000a]), when the myoplasm is completely localized in the vegetal region (excitable stage) and the ascidian egg cell is perturbed by an increase of Ca++ concentration in the culture medium, the cell reacts by showing persistent mechanical waves of contraction which exist as long as the cell is perturbed. Experimentally we observed the production of a polar lobe located in the vegetal region and the change of the inclination of mitotic furrow, after the appearance of a myoplasmic spiral wave in the vegetal pole. So we suppose that the myoplasmic spiral wave is due to a Ca++ spiral wave, and the myoplasmic spiral wave then causes the changes in the shape of the cell (polar lobe, inclination of mitotic furrow, etc.). Moreover we give a simple geometrical description of a spiral wave.

Vanadium Respiration by Geobacter metallireducens: Novel Strategy for In Situ Removal of Vanadium from Groundwater

PubMed Central

Ortiz-Bernad, Irene; Anderson, Robert T.; Vrionis, Helen A.; Lovley, Derek R.

2004-01-01

Vanadium can be an important contaminant in groundwaters impacted by mining activities. In order to determine if microorganisms of the Geobacteraceae, the predominant dissimilatory metal reducers in many subsurface environments, were capable of reducing vanadium(V), Geobacter metallireducens was inoculated into a medium in which acetate was the electron donor and vanadium(V) was the sole electron acceptor. Reduction of vanadium(V) resulted in the production of vanadium(IV), which subsequently precipitated. Reduction of vanadium(V) was associated with cell growth with a generation time of 15 h. No vanadium(V) was reduced and no precipitate was formed in heat-killed or abiotic controls. Acetate was the most effective of all the electron donors evaluated. When acetate was injected into the subsurface to enhance the growth and activity of Geobacteraceae in an aquifer contaminated with uranium and vanadium, vanadium was removed from the groundwater even more effectively than uranium. These studies demonstrate that G. metallireducens can grow via vanadium(V) respiration and that stimulating the activity of Geobacteraceae, and hence vanadium(V) reduction, can be an effective strategy for in situ immobilization of vanadium in contaminated subsurface environments. PMID:15128571

Patterns of chemical diversity in the marine ascidian Phallusia spp.: anti-tumor activity and metabolic pathway inhibiting steroid biosynthesis.

PubMed

Palanisamy, Satheesh Kumar; Arumugam, Velusamy; Peter, Magesh D; Sundaresan, Umamaheswari

2018-05-01

The complex nature of marine biodiversity is partially responsible for the lack of studies in Indian ascidian species, which often target a small number of novel biomolecules. We performed untargeted metabolomics using gas chromatography-mass spectrometry (GC-MS) in two invasive ascidian species to investigate the inter-specific chemical diversity of Phallusia nigra and P. arabica in search of drug-like properties and metabolic pathways. The chemical profiling of individual ascidian species was obtained using GC-MS, and the metabolites were determined by searching in NIST library and literature data. The principal component analysis of GC-MS mass spectral variables showed a clear discrimination of these two ascidian species based on the chemical composition and taxonomy. The metabolites, lipids, macrolides, and steroids contributed strongly to the discrimination of these two species. Results of this study confirmed that GC-MS-based chemical profiling could be utilized as a tool for chemotaxonomic classification of ascidian species. The extract of P. nigra showed promising anti-tumor activity against HT29 colon cancer 35 µM and MCF7-breast cancer (34.76 µM) cells compared to P. arabica . Of the more than 70 metabolites measured, 18 metabolites that mapped various pathways linked to three metabolic pathways being impacted and altered in steroid biosynthesis, primary bile acid biosynthesis, and steroid hormone biosynthesis were observed to have changed significantly ( p  > 0.004, FDR < 0.01). Also, higher expression of this pathway was associated with more significant cytotoxicity in breast and colon carcinoma cells.

Programmed cell death in vegetative development: apoptosis during the colonial life cycle of the ascidian Botryllus schlosseri.

PubMed

Tiozzo, S; Ballarin, L; Burighel, P; Zaniolo, G

2006-06-01

Programmed cell death (PCD) by apoptosis is a physiological mechanism by which cells are eliminated during embryonic and post-embryonic stages of animal life cycle. During asexual reproduction, the zooids of colonial ascidians originate from an assorted cell population instead of a single zygote, so that we assume that regulation of the equilibrium among proliferation, differentiation and cell death may follow different pathways in comparison to the embryonic development. Here we investigate the presence of apoptotic events throughout the blastogenetic life cycle of the colonial ascidian Botryllus schlosseri, by means of terminal deoxynucleotidyl transferase dUTP Nick End Labeling (TUNEL) coupled with histochemical and electron microscopy techniques. The occurrence of low levels of morphogenetic cell death suggests that, in contrast to what happens during sexual development (embryogenesis and metamorphosis), apoptosis does not play a pivotal role during asexual propagation in botryllid ascidian. Nevertheless, PCD emerges as a key force to regulate homeostasis in adult zooids and to shape and modulate the growth of the whole colony.

Sequential activation of apical and basolateral contractility drives ascidian endoderm invagination

PubMed Central

Sherrard, Kristin; Robin, François; Lemaire, Patrick; Munro1, Edwin

2014-01-01

SUMMARY Background Epithelial invagination is a fundamental morphogenetic behavior that transforms a flat cell sheet into a pit or groove. Previous studies of invagination have focused on the role of actomyosin-dependent apical contraction; other mechanisms remain largely unexplored. Results We combined experimental and computational approaches to identify a two-step mechanism for endoderm invagination during ascidian gastrulation. During Step 1, which immediately precedes invagination, endoderm cells constrict their apices due to Rho/Rhokinase-dependent apical enrichment of 1P–myosin. Our data suggest that endoderm invagination itself occurs during Step 2, without further apical shrinkage, via a novel mechanism we call collared rounding: Rho/Rho-kinase-independent lateral enrichment of 1P–myosin drives apico-basal shortening, while Rho/Rho-kinase-dependent enrichment of 1P and 2P myosin in circumapical collars is required to prevent apical expansion and for deep invagination. Simulations show that boundary-specific tension values consistent with these distributions of active myosin can explain the cell shape changes observed during invagination both in normal embryos and in embryos treated with pharmacological inhibitors of either Rho-kinase or Myosin II ATPase. Indeed, we find that the balance of strong circumapical and basolateral tension is the only mechanism based on differential cortical tension that can explain ascidian endoderm invagination. Finally, simulations suggest that mesectoderm cells resist endoderm shape changes during both steps and we confirm this prediction experimentally. Conclusions Our findings suggest that early ascidian gastrulation is driven by the coordinated apposition of circumapical and lateral endoderm contraction, working against a resisting mesectoderm. We propose that similar mechanisms may operate during other invaginations. PMID:20691592

Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983) in an Urban Estuary

PubMed Central

Wernberg, Thomas; McDonald, Justin I.

2016-01-01

Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia) growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis) where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future. PMID:27144600

Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983) in an Urban Estuary.

PubMed

Simpson, Tiffany Schenk; Wernberg, Thomas; McDonald, Justin I

2016-01-01

Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia) growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis) where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future.

Cytotoxic effect of vanadium and oil-fired fly ash on hamster tracheal epithelium

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

Schiff, L.J.; Graham, J.A.

1984-08-01

Hamster tracheal organ cultures were used to study the in vitro effects of vanadium and oil-fired fly ash on mucociliary respiratory epithelium. Two vanadium compounds, VOSO/sub 4/ and V/sub 2/O/sub 5/, and fly ash from an oil-fueled power plant were dissolved or suspended in culture medium over a range of concentrations and epithelia were exposed for 1 hr/day, for 9 consecutive days. At intervals during this period, alterations in cilia-beating frequency, cytology, and histology were documented by light microscopy. Explants treated with VOSO/sub 4/ either decreased ciliary activity or produced ciliostasis depending upon the concentration and length of exposure. Earlymore » morphological alterations consisted of vacuolization of both nuclei and cytoplasm. After multiple exposures, cytology of VOSO/sub 4/-treated respiratory mucosa was markedly affected. Similar changes were observed in cultures exposed to V/sub 2/O/sub 5/; however, the cytotoxicity appeared earlier and was more pronounced. Fly ash-treated explants produced similar biological effects when compared to both vanadium compounds. Thus, the data indicate that the extent of vanadium toxicity depends, at least in part, on the vanadium content of the compound tested, and that exposure to this metal and vanadium-rich fly ash can inhibit normal mucociliary function, a vital clearance mechanism in the respiratory tract.« less

Leaching characteristics of vanadium in mine tailings and soils near a vanadium titanomagnetite mining site.

PubMed

Yang, Jinyan; Tang, Ya; Yang, Kai; Rouff, Ashaki A; Elzinga, Evert J; Huang, Jen-How

2014-01-15

A series of column leaching experiments were performed to understand the leaching behaviour and the potential environmental risk of vanadium in a Panzhihua soil and vanadium titanomagnetite mine tailings. Results from sequential extraction experiments indicated that the mobility of vanadium in both the soil and the mine tailings was low, with <1% of the total vanadium readily mobilised. Column experiments revealed that only <0.1% of vanadium in the soil and mine tailing was leachable. The vanadium concentrations in the soil leachates did not vary considerably, but decreased with the leachate volume in the mine tailing leachates. This suggests that there was a smaller pool of leachable vanadium in the mine tailings compared to that in the soil. Drought and rewetting increased the vanadium concentrations in the soil and mine tailing leachates from 20μgL(-1) to 50-90μgL(-1), indicating the potential for high vanadium release following periods of drought. Experiments with soil columns overlain with 4, 8 and 20% volume mine tailings/volume soil exhibited very similar vanadium leaching behaviour. These results suggest that the transport of vanadium to the subsurface is controlled primarily by the leaching processes occurring in soils. Copyright © 2013 Elsevier B.V. All rights reserved.

Toxicity of marine pollutants on the ascidian oocyte physiology: an electrophysiological approach.

PubMed

Gallo, Alessandra

2018-02-01

In marine animals with external fertilization, gametes are released into seawater where fertilization and embryo development occur. Consequently, pollutants introduced into the marine environment by human activities may affect gametes and embryos. These xenobiotics can alter cell physiology with consequent reduction of fertilization success. Here the adverse effects on the reproductive processes of the marine invertebrate Ciona intestinalis (ascidian) of different xenobiotics: lead, zinc, an organic tin compound and a phenylurea herbicide were evaluated. By using the electrophysiological technique of whole-cell voltage clamping, the effects of these compounds on the mature oocyte plasma membrane electrical properties and the electrical events of fertilization were tested by calculating the concentration that induced 50% normal larval formation (EC50). The results demonstrated that sodium currents in mature oocytes were reduced in a concentration-dependent manner by all tested xenobiotics, with the lowest EC50 value for lead. In contrast, fertilization current frequencies were differently affected by zinc and organic tin compound. Toxicity tests on gametes demonstrated that sperm fertilizing capability and fertilization oocyte competence were not altered by xenobiotics, whereas fertilization was inhibited in zinc solution and underwent a reduction in organic tin compound solution (EC50 value of 1.7 µM). Furthermore, fertilized oocytes resulted in a low percentage of normal larvae with an EC50 value of 0.90 µM. This study shows that reproductive processes of ascidians are highly sensitive to xenobiotics suggesting that they may be considered a reliable biomarker and that ascidians are suitable model organisms to assess marine environmental quality.

Graphite furnace atomic absorption spectrometric determination of vanadium after cloud point extraction in the presence of graphene oxide

NASA Astrophysics Data System (ADS)

López-García, Ignacio; Marín-Hernández, Juan José; Hernández-Córdoba, Manuel

2018-05-01

Vanadium (V) and vanadium (IV) in the presence of a small concentration of graphene oxide (0.05 mg mL-1) are quantitatively transferred to the coacervate obtained with Triton X-114 in a cloud point microextraction process. The surfactant-rich phase is directly injected into the graphite atomizer of an atomic absorption spectrometer. Using a 10-mL aliquot sample and 150 μL of a 15% Triton X-114 solution, the enrichment factor for the analyte is 103, which results in a detection limit of 0.02 μg L-1 vanadium. The separation of V(V) and V(IV) using an ion-exchanger allows speciation of the element at low concentrations. Data for seven reference water samples with certified vanadium contents confirm the reliability of the procedure. Several beer samples are also analyzed, those supplied as canned drinks showing low levels of tetravalent vanadium.

Prochloron-ascidian symbioses: Photosynthetic potential and productivity

NASA Technical Reports Server (NTRS)

Lewin, R. A.; Cheng, L.; Alberte, R. S.

1983-01-01

The chlorophyll content of didemnid asidians with symbiotic algae (Prochloron) from oligotropic tropical marine waters around Palau, Western Carolin Islands is discussed. Several species contain as much chlorophyll per unit dry weight as many herbaceous crop plants and more than do other symbiotic associations such as lichens, green Hydra, etc. Their chlorphyllA/B ratios (3-9) were generally much lighter than those of angiosperms (2-4). Where they abound, Prochloron - ascidian symbiosis could make a major contribution to the productivity, especially in localized areas of tropical marine waters characterized by low nutrient levels and high irradiance.

THE GENERAL ECOLOGY AND GROWTH OF A SOLITARY ASCIDIAN, CORELLA WILLMERIANA.

PubMed

Lambert, Gretchen

1968-10-01

1. A one-year field study of the ecology of the solitary ascidian Corella willmeriana Herdman was conducted between April, 1966, and April, 1967, at the Bremerton Yacht Club, Bremerton, Washington, where two polyvinyl chloride frames containing glass plates were examined at monthly intervals. 2. The results indicate that Corella is a primary colonizer, preferring to settle on clean surfaces. Growth is rapid during the summer, when sexual maturity, corresponding to a size of 12 mm., may be attained in three months and life span is approximately five months. Individuals grow at a slower rate and live longer during the winter; the life span then is seven or eight months. 3. Very young specimens of Corella are frequently overgrown during the winter by the colonial ascidian Diplosoma macdonaldi. The causes of death of adult Corella are not completely known, although a small percentage of them are eaten by the polyclad flatworm Eurylepta leoparda. A luxuriant spring growth of filamentous diatoms may cause death of adult Corella by smothering them.

Thirty years through vanadium chemistry.

PubMed

Costa Pessoa, J

2015-06-01

The relevance of vanadium in biological systems is known for many years and vanadium-based catalysts have important industrial applications, however, till the beginning of the 80s research on vanadium chemistry and biochemistry did not receive much attention from the scientific community. The understanding of the broad bioinorganic implications resulting from the similarities between phosphate and vanadate(V) and the discovery of vanadium dependent enzymes gave rise to an enormous increase in interest in the chemistry and biological relevance of vanadium. Thereupon the last 30years corresponded to a period of enormous research effort in these fields, as well as in medicinal applications of vanadium and in the development of catalysts for use in fine-chemical synthesis, some of these inspired by enzymatic active sites. Since the 80s my group in collaboration with others made contributions, described throughout this text, namely in the understanding of the speciation of vanadium compounds in aqueous solution and in biological fluids, and to the transport of vanadium compounds in blood plasma and their uptake by cells. Several new types of vanadium compounds were also synthesized and characterized, with applications either as prospective therapeutic drugs or as homogeneous or heterogenized catalysts for the production of fine chemicals. The developments made are described also considering the international context of the evolution of the knowledge in the chemistry and bioinorganic chemistry of vanadium compounds during the last 30years. This article was compiled based on the Vanadis Award presentation at the 9th International Vanadium Symposium. Copyright © 2015 Elsevier Inc. All rights reserved.

Exploring the mechanism of action of the sperm-triggered calcium-wave pacemaker in ascidian zygotes.

PubMed

Carroll, Michael; Levasseur, Mark; Wood, Chris; Whitaker, Michael; Jones, Keith T; McDougall, Alex

2003-12-15

In ascidians, as in mammals, sperm trigger repetitive Ca2+-waves that originate from cortical pacemakers situated in the vegetal hemisphere of the zygotes. In ascidians, a vegetal protrusion termed the contraction pole (CP) acts as the Ca2+-wave pacemaker, but the mechanism that underlies the generation of a Ca2+-wave pacemaker is not known. Here, we tested four hypotheses to determine which factors at the CP are involved in setting the pace of the ascidian Ca2+-wave pacemaker: (1) localized Ca2+ influx; (2) accumulation of phosphatidylinositol (4,5)bisphosphate [PtdIns(4,5)P2]; (3) accumulation of cortical endoplasmic reticulum (cER); and (4) enrichment of the sperm activating factor. We developed a method of dynamically monitoring the location of the CP during fertilization using a plekstrin homology (PH) domain from phospholipase Cdelta1 coupled to green fluorescent protein (GFP) that binds PtdIns(4,5)P2. We found that eggs in Ca2+-free sea water displayed Ca2+ waves that originated from the CP, showing that enhanced CP Ca2+ influx does not determine the origin of the pacemaker. Also, disruption of the PH::GFP-labelled CP once it had formed did not dislodge the Ca2+-wave pacemaker from that site. Next, when we prevented the accumulation of cER at the CP, all of the Ca2+ waves came from the site of sperm-egg fusion and the frequency of Ca2+ oscillations was unaltered. These data show that local Ca2+ influx, the accumulation of PtdIns(4,5)P2 and cER at the CP are not required for Ca2+-wave pacemaker function and instead suggest that a factor associated with the sperm determines the site of the Ca2+-wave pacemaker. Finally, when we injected ascidian sperm extract into the centre of unfertilized ascidian eggs that had been treated with microfilament- and microtubule-disrupting drugs, all the Ca2+ waves still originated from near the plasma membrane, showing that the sperm factor does not require an intact cortex if it is enriched near the plasma membrane (PM). We

Microenvironmental Ecology of the Chlorophyll b-Containing Symbiotic Cyanobacterium Prochloron in the Didemnid Ascidian Lissoclinum patella

PubMed Central

Kühl, Michael; Behrendt, Lars; Trampe, Erik; Qvortrup, Klaus; Schreiber, Ulrich; Borisov, Sergey M.; Klimant, Ingo; Larkum, Anthony W. D.

2012-01-01

The discovery of the cyanobacterium Prochloron was the first finding of a bacterial oxyphototroph with chlorophyll (Chl) b, in addition to Chl a. It was first described as Prochloron didemni but a number of clades have since been described. Prochloron is a conspicuously large (7–25 μm) unicellular cyanobacterium living in a symbiotic relationship, primarily with (sub-) tropical didemnid ascidians; it has resisted numerous cultivation attempts and appears truly obligatory symbiotic. Recently, a Prochloron draft genome was published, revealing no lack of metabolic genes that could explain the apparent inability to reproduce and sustain photosynthesis in a free-living stage. Possibly, the unsuccessful cultivation is partly due to a lack of knowledge about the microenvironmental conditions and ecophysiology of Prochloron in its natural habitat. We used microsensors, variable chlorophyll fluorescence imaging and imaging of O2 and pH to obtain a detailed insight to the microenvironmental ecology and photobiology of Prochloron in hospite in the didemnid ascidian Lissoclinum patella. The microenvironment within ascidians is characterized by steep gradients of light and chemical parameters that change rapidly with varying irradiances. The interior zone of the ascidians harboring Prochloron thus became anoxic and acidic within a few minutes of darkness, while the same zone exhibited O2 super-saturation and strongly alkaline pH after a few minutes of illumination. Photosynthesis showed lack of photoinhibition even at high irradiances equivalent to full sunlight, and photosynthesis recovered rapidly after periods of anoxia. We discuss these new insights on the ecological niche of Prochloron and possible interactions with its host and other microbes in light of its recently published genome and a recent study of the overall microbial diversity and metagenome of L. patella. PMID:23226144

Pharmacokinetics of vanadium in humans after intravenous administration of a vanadium containing albumin solution

PubMed Central

Heinemann, Günter; Fichtl, Burckhard; Vogt, Wolfgang

2003-01-01

Aims Vanadium is currently undergoing clinical trials as an oral drug in patients with noninsulin-dependent diabetes mellitus. Furthermore, vanadium occurs in elevated concentrations in the blood of patients receiving intravenous albumin solutions containing large amounts of the metal ion as an impurity. The present study was performed to examine the pharmacokinetics of vanadium in humans following a single intravenous (i.v.) dose of a commercial albumin solution containing a high amount of vanadium. Methods The study was conducted in five healthy volunteer subjects who received intravenously 90 ml of a commercial 20% albumin infusion solution containing 47.6 µg vanadium as an impurity. Vanadium concentrations in serum and urine were determined by electrothermal atomic absorption spectrometry. Results Vanadium serum concentrations after i.v. administration were measured for 31 days. The data could be fitted by a triexponential function corresponding formally to a three-compartment model. There was an initial rapid decrease in serum concentrations with half-lives of 1.2 and 26 h. This was followed by a long-terminal half-life time of 10 days. The terminal phase accounted for about 80% of the total area under the serum concentration-time curve (AUC). The mean apparent volume of distribution of the central compartment was found to be 10 l. The volume of distribution at steady state was 54 l, and total clearance was 0.15 l h−1. Vanadium was mainly excreted by the kidneys. About 52% of the dose was recovered in the urine after 12 days. Conclusions This study provides data on vanadium pharmacokinetics in healthy humans. PMID:12630973

An extraction process to recover vanadium from low-grade vanadium-bearing titanomagnetite.

PubMed

Chen, Desheng; Zhao, Hongxin; Hu, Guoping; Qi, Tao; Yu, Hongdong; Zhang, Guozhi; Wang, Lina; Wang, Weijing

2015-08-30

An extraction process to recover vanadium from low-grade vanadium-bearing titanomagnetite was developed. In this study, a mixed solvent system of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) diluted with kerosene was used for the selective extraction of vanadium from a hydrochloric acid leaching solution that contained low vanadium concentration with high concentrations of iron and impurities of Ca, Mg, and Al. In the extraction process, the initial solution pH and the phase ratio had considerable functions in the extraction of vanadium from the hydrochloric acid leaching solution. Under optimal extraction conditions (i.e., 30-40°C for 10min, 1:3 phase ratio (O/A), 20% D2EHPA concentration (v/v), and 0-0.8 initial solution pH), 99.4% vanadium and only 4.2% iron were extracted by the three-stage counter-current extraction process. In the stripping process with H2SO4 as the stripping agent and under optimal stripping conditions (i.e., 20% H2SO4 concentration, 5:1 phase ratio (O/A), 20min stripping time, and 40°C stripping temperature), 99.6% vanadium and only 5.4% iron were stripped by the three-stage counter-current stripping process. The stripping solution contained 40.16g/LV2O5,0.691g/L Fe, 0.007g/L TiO2, 0.006g/L SiO2 and 0.247g/L CaO. A V2O5 product with a purity of 99.12% V2O5 and only 0.026% Fe was obtained after the oxidation, precipitation, and calcination processes. The total vanadium recovered from the hydrochloric acid leaching solution was 85.5%. Copyright © 2015 Elsevier B.V. All rights reserved.

Whole-organ cell shape analysis reveals the developmental basis of ascidian notochord taper

PubMed Central

Veeman, Michael T.; Smith, William C.

2012-01-01

Here we use in toto imaging together with computational segmentation and analysis methods to quantify the shape of every cell at multiple stages in the development of a simple organ: the notochord of the ascidian Ciona savignyi. We find that cell shape in the intercalated notochord depends strongly on anterior-posterior (AP) position, with cells in the middle of the notochord consistently wider than cells at the anterior or posterior. This morphological feature of having a tapered notochord is present in many chordates. We find that ascidian notochord taper involves three main mechanisms: Planar Cell Polarity (PCP) pathway-independent sibling cell volume asymmetries that precede notochord cell intercalation; the developmental timing of intercalation, which proceeds from the anterior and posterior towards the middle; and the differential rates of notochord cell narrowing after intercalation. A quantitative model shows how the morphology of an entire developing organ can be controlled by this small set of cellular mechanisms. PMID:23165294

Whole-organ cell shape analysis reveals the developmental basis of ascidian notochord taper.

PubMed

Veeman, Michael T; Smith, William C

2013-01-15

Here we use in toto imaging together with computational segmentation and analysis methods to quantify the shape of every cell at multiple stages in the development of a simple organ: the notochord of the ascidian Ciona savignyi. We find that cell shape in the intercalated notochord depends strongly on anterior-posterior (AP) position, with cells in the middle of the notochord consistently wider than cells at the anterior or posterior. This morphological feature of having a tapered notochord is present in many chordates. We find that ascidian notochord taper involves three main mechanisms: Planar Cell Polarity (PCP) pathway-independent sibling cell volume asymmetries that precede notochord cell intercalation; the developmental timing of intercalation, which proceeds from the anterior and posterior towards the middle; and the differential rates of notochord cell narrowing after intercalation. A quantitative model shows how the morphology of an entire developing organ can be controlled by this small set of cellular mechanisms. Copyright © 2012 Elsevier Inc. All rights reserved.

(beta)-catenin mediates the specification of endoderm cells in ascidian embryos.

PubMed

Imai, K; Takada, N; Satoh, N; Satou, Y

2000-07-01

In the present study, we addressed the role of (beta)-catenin in the specification of embryonic cells of the ascidians Ciona intestinalis and C. savignyi and obtained the following results: (1) During cleavages, (beta)-catenin accumulated in the nuclei of vegetal blastomeres, suggesting that it plays a role in the specification of endoderm. (2) Mis- and/or overexpression of (beta)-catenin induced the development of an endoderm-specific alkaline phosphatase (AP) in presumptive notochord cells and epidermis cells without affecting differentiation of primary lineage muscle cells. (3) Downregulation of (beta)-catenin induced by the overexpression of cadherin resulted in the suppression of endoderm cell differentiation. This suppression was compensated for by the differentiation of extra epidermis cells. (4) Specification of notochord cells did not take place in the absence of endoderm differentiation. Both the overexpression of (beta)-catenin in presumptive notochord cells and the downregulation of (beta)-catenin in presumptive endoderm cells led to the suppression of Brachyury gene expression, resulting in the failure of notochord specification. These results suggest that the accumulation of (beta)-catenin in the nuclei of endoderm progenitor cells is the first step in the process of ascidian endoderm specification.

Inverse Correlation of Population Similarity and Introduction Date for Invasive Ascidians

PubMed Central

Silva, Nathan; Smith, William C.

2008-01-01

The genomes of many marine invertebrates, including the purple sea urchin and the solitary ascidians Ciona intestinalis and Ciona savignyi, show exceptionally high levels of heterozygosity, implying that these populations are highly polymorphic. Analysis of the C. savignyi genome found little evidence to support an elevated mutation rate, but rather points to a large population size contributing to the polymorphism level. In the present study, the relative genetic polymorphism levels in sampled populations of ten different ascidian species were determined using a similarity index generated by AFLP analysis. The goal was to determine the range of polymorphism within the populations of different species, and to uncover factors that may contribute to the high level of polymorphism. We observe that, surprisingly, the levels of polymorphism within these species show a negative correlation with the reported age of invasive populations, and that closely related species show substantially different levels of genetic polymorphism. These findings show exceptions to the assumptions that invasive species start with a low level of genetic polymorphism that increases over time and that closely related species have similar levels of genetic polymorphism. PMID:18575620

VANADIUM ALLOYS

DOEpatents

Smith, K.F.; Van Thyne, R.J.

1959-05-12

This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

A method for recovery of iron, titanium, and vanadium from vanadium-bearing titanomagnetite

NASA Astrophysics Data System (ADS)

Zhang, Yi-min; Wang, Li-na; Chen, De-sheng; Wang, Wei-jing; Liu, Ya-hui; Zhao, Hong-xin; Qi, Tao

2018-02-01

An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.

The invariant cleavage pattern displayed by ascidian embryos depends on spindle positioning along the cell's longest axis in the apical plane and relies on asynchronous cell divisions

PubMed Central

Dumollard, Rémi; Minc, Nicolas; Salez, Gregory; Aicha, Sameh Ben; Bekkouche, Faisal; Hebras, Céline; Besnardeau, Lydia; McDougall, Alex

2017-01-01

The ascidian embryo is an ideal system to investigate how cell position is determined during embryogenesis. Using 3D timelapse imaging and computational methods we analyzed the planar cell divisions in ascidian early embryos and found that spindles in every cell tend to align at metaphase in the long length of the apical surface except in cells undergoing unequal cleavage. Furthermore, the invariant and conserved cleavage pattern of ascidian embryos was found to consist in alternate planar cell divisions between ectoderm and endomesoderm. In order to test the importance of alternate cell divisions we manipulated zygotic transcription induced by β-catenin or downregulated wee1 activity, both of which abolish this cell cycle asynchrony. Crucially, abolishing cell cycle asynchrony consistently disrupted the spindle orienting mechanism underpinning the invariant cleavage pattern. Our results demonstrate how an evolutionary conserved cell cycle asynchrony maintains the invariant cleavage pattern driving morphogenesis of the ascidian blastula. DOI: http://dx.doi.org/10.7554/eLife.19290.001 PMID:28121291

[Oxidative Stress Level of Vanadium-exposed Workers].

PubMed

Wei, Teng-da; Li, Shun-pin; Liu, Yun-xing; Tan, Chun-ping; Li, Juan; Zhang, Zu-hui; Lan, Ya-jia; Zhang, Qin

2015-11-01

To determine the oxidative stress level in peripheral blood of vanadium-exposed workers, as an indication of population health effect of vanadium on human neurobehavioral system. 86 vanadium-exposed workers and 65 non-exposed workers were recruited by cluster sampling. A questionnaire was administered to collect demographic and occupational exposure information. Serum activity of superoxide dismutase (SOD), inducible nitric oxide synthase (iNOS) and malonaldehyde (MDA) contents were detected by kit assay. The differences in oxidative stress level between vanadium-exposed and non-exposed workers were compared. Vanadium-exposed workers had higher levels of MDA contents than the controls. The total superoxide dismutase(T-SOD) activity in vanadium-exposed workers was significantly lower than that in the controls, which was associated with lowered levels of manganese superoxide dismutase (Mn-SOD) activity. No changes in serum levels of cupro-zinc superoxide dismutase (CuZn-SOD) was found in vanadium-exposed workers. No difference in iNOS activity was found between vanadium-exposed workers and controls. Vanadium exposure increases free radical production in serum and reduces antioxidant capacity. But the relationship between vanadium exposure and iNOS damage remains uncertain.

Vanadium distribution in rats and DNA cleavage by vanadyl complex: implication for vanadium toxicity and biological effects.

PubMed Central

Sakurai, H

1994-01-01

Vanadium ion is toxic to animals. However, vanadium is also an agent used for chemoprotection against cancers in animals. To understand both the toxic and beneficial effects we studied vanadium distribution in rats. Accumulation of vanadium in the liver nuclei of rats given low doses of compounds in the +4 or +5 oxidation state was greater than in the liver nuclei of rats given high doses of vanadium compounds or the vanadate (+5 oxidation state) compound. Vanadium was incorporated exclusively in the vanadyl (+4 oxidation state) form. We also investigated the reactions of vanadyl ion and found that incubation of DNA with vanadyl ion and hydrogen peroxide (H2O2) led to intense DNA cleavage. ESR spin trapping demonstrated that hydroxyl radicals are generated during the reactions of vanadyl ion and H2O2. Thus, we propose that the mechanism for vanadium-dependent toxicity and antineoplastic action is due to DNA cleavage by hydroxyl radicals generated in living systems. PMID:7843133

Brachyury downstream notochord differentiation in the ascidian embryo

PubMed Central

Takahashi, Hiroki; Hotta, Kohji; Erives, Albert; Di Gregorio, Anna; Zeller, Robert W.; Levine, Michael; Satoh, Nori

1999-01-01

The ascidian tadpole represents the most simplified chordate body plan. It contains a notochord composed of just 40 cells, but as in vertebrates Brachyury is essential for notochord differentiation. Here, we show that the misexpression of the Brachyury gene (Ci-Bra) of Ciona intestinalis is sufficient to transform endoderm into notochord. Subtractive hybridization screens were conducted to identify potential Brachyury target genes that are induced upon Ci-Bra misexpression. Of 501 independent cDNA clones that were surveyed, 38 were specifically expressed in notochord cells. These potential Ci-Bra downstream genes appear to encode a broad spectrum of divergent proteins associated with notochord formation. PMID:10385620

Ascidian introductions through the Suez Canal: The case study of an Indo-Pacific species.

PubMed

Rius, Marc; Shenkar, Noa

2012-10-01

Although marine biological invasions via the Suez Canal have been extensively documented, little is known about the introduction of non-indigenous ascidians (Chordata, Ascidiacea), a group containing particularly aggressive invasive species. Here, we used a multidisciplinary approach to study the introduction of the ascidian Herdmania momus into the Mediterranean Sea. We reviewed its taxonomy and global distribution, and analyzed how genetic variation is partitioned between sides of the Suez Canal. The taxonomic revision showed that H. momus currently has a wide Indo-Pacific distribution. Genetic data indicated two well-differentiated colonization histories across the eastern Mediterranean. Our findings suggest that the range expansion of H. momus has been greatly facilitated by the combined effect of human-mediated transport and the species' ability to adapt to different environments. The integrative approach presented here is critical to attain a holistic understanding of marine biological invasions, especially when studying groups with a poorly resolved taxonomy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cytoskeletal actin genes function downstream of HNF-3beta in ascidian notochord development.

PubMed

Jeffery, W R; Ewing, N; Machula, J; Olsen, C L; Swalla, B J

1998-11-01

We have examined the expression and regulation of cytoskeletal actin genes in ascidians with tailed (Molgula oculata) and tailless larvae (Molgula occulta). Four cDNA clones were isolated representing two pairs of orthologous cytoskeletal actin genes (CA1 and CA2), which encode proteins differing by five amino acids in the tailed and tailless species. The CA1 and CA2 genes are present in one or two copies, although several related genes may also be present in both species. Maternal CA1 and CA2 mRNA is present in small oocytes but transcript levels later decline, suggesting a role in early oogenesis. In the tailed species, embryonic CA1 and CA2 mRNAs first appear in the presumptive mesenchyme and muscle cells during gastrulation, subsequently accumulate in the presumptive notochord cells, and can be detected in these tissues through the tadpole stage. CA1 mRNAs accumulate initially in the same tissues in the tailless species but subsequently disappear, in concert with the arrest of notochord and tail development. In contrast, CA2 mRNAs were not detected in embryos of the tailless species. Fertilization of eggs of the tailless species with sperm of the tailed species, which restores the notochord and the tail, also results in the upregulation of CA1 and CA2 gene expression in hybrid embryos. Antisense oligodeoxynucleotide experiments suggest that CA1 and CA2 expression in the notochord, but not in the muscle cells, is dependent on prior expression of Mocc FHI, an ascidian HNF-3beta-like gene. The expression of the CA1 and CA2 genes in the notochord in the tailed species, downregulation in the tailless species, upregulation in interspecific hybrids, and dependence on HNF-3beta activity is consistent with a role of these genes in development of the ascidian notochord.

Strategies for sperm chemotaxis in the siphonophores and ascidians: a numerical simulation study.

PubMed

Ishikawa, Makiko; Tsutsui, Hidekazu; Cosson, Jacky; Oka, Yoshitaka; Morisawa, Masaaki

2004-04-01

Chemotactic swimming behaviors of spermatozoa toward an egg have been reported in various species. The strategies underlying these behaviors, however, are poorly understood. We focused on two types of chemotaxis, one in the siphonophores and the second in the ascidians, and then proposed two models based on experimental data. Both models assumed that the radius of the path curvature of a swimming spermatozoon depends on [Ca(2+)](i), the intracellular calcium concentration. The chemotaxis in the siphonophores could be simulated in a model that assumes that [Ca(2+)](i) depends on the local concentration of the attractant in the vicinity of the spermatozoon and that a substantial time period is required for the clearance of transient high [Ca(2+)](i). In the case of ascidians, trajectories similar to those in experiments could be adequately simulated by a variant of this model that assumes that [Ca(2+)](i) depends on the time derivative of the attractant concentration. The properties of these strategies and future problems are discussed in relation to these models.

Extraction of Vanadium from Vanadium Slag Via Non-salt Roasting and Ammonium Oxalate Leaching

NASA Astrophysics Data System (ADS)

Li, Meng; Du, Hao; Zheng, Shili; Wang, Shaona; Zhang, Yang; Liu, Biao; Dreisinger, David Bruce; Zhang, Yi

2017-10-01

A clean method featuring non-salt roasting followed by (NH4)2C2O4 leaching to recover vanadium from vanadium slag was proposed. The carcinogenic Cr6+ compounds and exhaust gases were avoided, and the water generated from vanadate precipitation may be recycled and reused in this new leaching process. The leaching residues may be easily used by a blast furnace. Moreover, (NH4)2C2O4 solution was used as a leaching medium to avoid expensive and complicated ammonium controlling operations as a result of the stability of (NH4)2C2O4 at a high temperature. The transformation mechanisms of vanadium- and chromium-bearing phases were systematically investigated by x-ray diffraction analysis and scanning electron microscopy with energy-disperse x-ray spectrometry, respectively. In addition, the effects of oxygen concentration, roasting temperature, and holding time on vanadium recovery were investigated. Finally, the effects of leaching variables on the vanadium leaching rate were also examined.

Effects of dietary vanadium in mallard ducks

USGS Publications Warehouse

White, D.H.; Dieter, M.P.

1978-01-01

Adult mallard ducks fed 0, 1, 10, or 100 ppm vanadyl sulfate in the diet were sacrificed after 12 wk on treatment; tissues were analyzed for vanadium. No birds died during the study and body weights did not change. Vanadium accumulated to higher concentrations in the bone and liver than in other tissues. Concentrations in bones of hens were five times those in bones of drakes, suggesting an interaction between vanadium and calcium mobilization in laying hens. Vanadium concentrations in most tissues were significantly correlated and increased with treatment level. Lipid metabolism was altered in laying hens fed 100 ppm vanadium. Very little vanadium accumulated in the eggs of laying hens.

Release kinetics of vanadium from vanadium (III, IV and V) oxides: Effect of pH, temperature and oxide dose.

PubMed

Hu, Xingyun; Yue, Yuyan; Peng, Xianjia

2018-05-01

Batch experiments were performed to derive the rate laws for the proton-promoted dissolution of the main vanadium (III, IV and V) oxides at pH 3.1-10.0. The release rates of vanadium are closely related to the aqueous pH, and several obvious differences were observed in the release behavior of vanadium from the dissolution of V 2 O 5 and vanadium(III, IV) oxides. In the first 2hr, the release rates of vanadium from V 2 O 3 were r=1.14·([H + ]) 0.269 at pH 3.0-6.0 and r=0.016·([H + ]) -0.048 at pH 6.0-10.0; the release rates from VO 2 were r=0.362·([H + ]) 0.129 at pH 3.0-6.0 and r=0.017·([H + ]) -0.097 at pH 6.0-10.0; and the release rates from V 2 O 5 were r=0.131·([H + ]) -0.104 at pH 3.1-10.0. The release rates of vanadium from the three oxides increased with increasing temperature, and the effect of temperature was different at pH 3.8, pH 6.0 and pH 7.7. The activation energies of vanadium (III, IV and V) oxides (33.4-87.5kJ/mol) were determined at pH 3.8, pH6.0 and pH 7.7, showing that the release of vanadium from dissolution of vanadium oxides follows a surface-controlled reaction mechanism. The release rates of vanadium increased with increasing vanadium oxides dose, albeit not proportionally. This study, as part of a broader study of the release behavior of vanadium, can help to elucidate the pollution problem of vanadium and to clarify the fate of vanadium in the environment. Copyright © 2017. Published by Elsevier B.V.

SUPERCONDUCTING VANADIUM BASE ALLOY

DOEpatents

Cleary, H.J.

1958-10-21

A new vanadium-base alloy which possesses remarkable superconducting properties is presented. The alloy consists of approximately one atomic percent of palladium, the balance being vanadium. The alloy is stated to be useful in a cryotron in digital computer circuits.

Speciation of vanadium in Chinese cabbage (Brassica rapa L.) and soils in response to different levels of vanadium in soils and cabbage growth.

PubMed

Tian, Liyan; Yang, Jinyan; Alewell, Christine; Huang, Jen-How

2014-09-01

This study highlights the accumulation and speciation of vanadium in Chinese cabbage (Brassica rapa L.) in relation to the speciation of soil vanadium with pot experiments at 122-622mgVkg(-1) by spiking NH4VO3. Cabbage planting decreased the bioavailable and residual vanadium based on sequential extraction, leading to enrichment of oxalate-extractable vanadium in soils. The biomass production increased with increasing concentrations of soil vanadium from 122 to 372mgVkg(-1), probably due to the increasing nitrogen availability and low vanadium availability in our soils with a consequent low vanadium toxicity. Although the concentrations of root vanadium (14.4-24.9mgVkg(-1)) related positively with soil vanadium, the bio-dilution alleviated the increase of leaf vanadium (2.1-2.7mgVkg(-1)). The predominance of vanadium(IV) in leaves (∼60-80% of total vanadium) indicates bio-reduction of vanadium in Chinese cabbage, since the mobile vanadium in oxic soils was usually pentavalent. Approximately 15-20% of the leaf vanadium was associated with recalcitrant leaf tissues. The majority of leaf vanadium was water and ethanol extractable, which is considered mobile and may cause more toxic effects on Chinese cabbage. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of vanadium on serum lipid and lipoprotein profiles: a population-based study among vanadium exposed workers

PubMed Central

2014-01-01

Background Some experimental animal studies reported that vanadium had beneficial effects on blood total cholesterol (TC) and triglyceride (TG). However, the relationship between vanadium exposure and lipid, lipoprotein profiles in human subjects remains uncertain. This study aimed to compare the serum lipid and lipoprotein profiles of occupational vanadium exposed and non-exposed workers, and to provide human evidence on serum lipid, lipoprotein profiles and atherogenic indexes changes in relation to vanadium exposure. Methods This cross-sectional study recruited 533 vanadium exposed workers and 241 non-exposed workers from a Steel and Iron Group in Sichuan, China. Demographic characteristics and occupational information were collected through questionnaires. Serum lipid and lipoprotein levels were measured for all participants. The ratios of total cholesterol to high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) to HDL-C and apoB to apoA-I were used as atherogenic indexes. A general linear model was applied to compare outcomes of the two groups while controlling possible confounders and multivariate logistic regression was performed to evaluate the relationship between low HDL-C level, abnormal atherogenic index and vanadium exposure. Results Higher levels of HDL-C and apoA-I could be observed in the vanadium exposed group compared with the control group (P < 0.05). Furthermore, atherogenic indexes (TC/HDL-C, LDL-C/HDL-C, and apoB/apoA-I ratios) were found statistically lower in the vanadium exposed workers (P < 0.05). Changes in HDL-C, TC/HDL-C, and LDL-C/HDL-C were more pronounced in male workers than that in female workers. In male workers, after adjusting for potential confounding variables as age, habits of smoking and drinking, occupational vanadium exposure was still associated with lower HDL-C (OR 0.41; 95% CI, 0.27-0.62) and abnormal atherogenic index (OR 0.38; 95% CI, 0.20-0.70). Conclusion Occupational

Efficient Separation and Extraction of Vanadium and Chromium in High Chromium Vanadium Slag by Selective Two-Stage Roasting-Leaching

NASA Astrophysics Data System (ADS)

Wen, Jing; Jiang, Tao; Xu, Yingzhe; Liu, Jiayi; Xue, Xiangxin

2018-06-01

Vanadium and chromium are important rare metals, leading to a focus on high chromium vanadium slag (HCVS) as a potential raw material to extract vanadium and chromium in China. In this work, a novel method based on selective two-stage roasting-leaching was proposed to separate and extract vanadium and chromium efficiently in HCVS. XRD, FT-IR, and SEM were utilized to analyze the phase evolutions and microstructure during the whole process. Calcification roasting, which can calcify vanadium selectively using thermodynamics, was carried out in the first roasting stage to transfer vanadium into acid-soluble vanadate and leave chromium in the leaching residue as (Fe0.6Cr0.4)2O3 after H2SO4 leaching. When HCVS and CaO were mixed in the molar ratio CaO/V2O3 (n(CaO)/n(V2O3)) of 0.5 to 1.25, around 90 pct vanadium and less than 1 pct chromium were extracted in the first leaching liquid, thus achieving the separation of vanadium and chromium. In the second roasting stage, sodium salt, which combines with chromium easily, was added to the first leaching residue to extract chromium and 95.16 pct chromium was extracted under the optimal conditions. The total vanadium and chromium leaching rates were above 95 pct, achieving the efficient separation and extraction of vanadium and chromium. The established method provides a new technique to separate vanadium and chromium during roasting rather than in the liquid form, which is useful for the comprehensive application of HCVS.

Efficient Separation and Extraction of Vanadium and Chromium in High Chromium Vanadium Slag by Selective Two-Stage Roasting-Leaching

NASA Astrophysics Data System (ADS)

Wen, Jing; Jiang, Tao; Xu, Yingzhe; Liu, Jiayi; Xue, Xiangxin

2018-04-01

Vanadium and chromium are important rare metals, leading to a focus on high chromium vanadium slag (HCVS) as a potential raw material to extract vanadium and chromium in China. In this work, a novel method based on selective two-stage roasting-leaching was proposed to separate and extract vanadium and chromium efficiently in HCVS. XRD, FT-IR, and SEM were utilized to analyze the phase evolutions and microstructure during the whole process. Calcification roasting, which can calcify vanadium selectively using thermodynamics, was carried out in the first roasting stage to transfer vanadium into acid-soluble vanadate and leave chromium in the leaching residue as (Fe0.6Cr0.4)2O3 after H2SO4 leaching. When HCVS and CaO were mixed in the molar ratio CaO/V2O3 (n(CaO)/n(V2O3)) of 0.5 to 1.25, around 90 pct vanadium and less than 1 pct chromium were extracted in the first leaching liquid, thus achieving the separation of vanadium and chromium. In the second roasting stage, sodium salt, which combines with chromium easily, was added to the first leaching residue to extract chromium and 95.16 pct chromium was extracted under the optimal conditions. The total vanadium and chromium leaching rates were above 95 pct, achieving the efficient separation and extraction of vanadium and chromium. The established method provides a new technique to separate vanadium and chromium during roasting rather than in the liquid form, which is useful for the comprehensive application of HCVS.

Commercialization of the Chevron FCC vanadium trap

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

Kennedy, J.V.; Kuehler, C.W.; Krishna, A.S.

1995-09-01

Vanadium, present to varying degrees in FCC feed, deposits on the catalyst virtually quantitatively in the cracking process. In resid operations, vanadium levels on catalyst can reach 10,000 ppm at typical catalyst make-up rates. Once on the catalyst, vanadium destroys the zeolite and restricts access to active sites. This reduces catalyst activity. A vanadium trap is a material that when introduced into the catalyst inventory selectively reacts with migrating vanadium, thus protecting the zeolite and other active components of the catalyst. The trap may be incorporated into the catalyst, or introduced as a separate particle. Only a limited amount ofmore » trap can be incorporated into the catalyst without limiting the amount of zeolite that can be included. Gulf began development of a vanadium trap during the early 1980`s. The work produced a variety of promising materials whose use as vanadium traps was subsequently patented. The work ultimately led to a formulation with a phase very active for trapping vanadium while still quite sulfur tolerant. Based on these results, an extensive pilot plant evaluation was undertaken by Chevron after the Chevron-Gulf merger to better simulate commercial operation. The paper describes pilot plant tests as well as 3 commercial tests of this vanadium trap.« less

Controlled coordination in vanadium(V) dimethylhydrazido compounds.

PubMed

Sakuramoto, Takashi; Moriuchi, Toshiyuki; Hirao, Toshikazu

2016-11-01

The vanadium(V) dimethylhydrazido compounds were structurally characterized to elucidate the effect of the alkoxide ligands in the coordination environment of vanadium(V) hydrazido center. The single-crystal X-ray structure determination of the vanadium(V) dimethylhydrazido compound with isopropoxide ligands revealed a dimeric structure with the V(1)-N(1) distance of 1.680(5)Å, in which each vanadium atom is coordinated in a distorted trigonal-bipyramidal geometry (τ 5 =0.81) with the hydrazido and bridging isopropoxide ligands in the apical positions. On the contrary, nearly tetrahedral arrangement around the vanadium metal center (τ 4 =0.06) with the V(1)-N(1) distance of 1.660(2)Å was observed in the vanadium(V) dimethylhydrazido compound with tert-butoxide ligands. The introduction of the 2,2',2″-nitrilotriethoxide ligand led to a pseudo-trigonal-bipyramidal geometry (τ 5 =0.92) at the vanadium center with the V(1)-N(1) distance of 1.691(5)Å, wherein vanadium atom is pulled out of the plane formed by the nitrilotriethoxide oxygen atoms in the direction of the hydrazido nitrogen. The coordination from the apical ligand in the vanadium(V) dimethylhydrazido compound was found to result in the longer V(1)-N(1) distance. Copyright © 2016 Elsevier Inc. All rights reserved.

Homology of vanadium oxide

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

Vasyutinskii, N.A.

1987-05-01

The authors examine the homology of vanadium oxide and note that data on the existence of phases and homogeneity limits in the V-O system are very contradictory. A graphical illustration shows the homologous series of vanadium oxides. The predominant part of the discrete formations in the system V-O is characterized by integral stoichiometry and forms six homologous series. It is found that homologous series of vanadium oxides are not only a basis for systematization of such oxides, but also may serve as a means for predicting the composition of new phases, limits of homogeneity, their structure, and properties.

Vanadium recycling in the United States in 2004

USGS Publications Warehouse

Goonan, Thomas G.

2011-01-01

As one of a series of reports that describe the recycling of metal commodities in the United States, this report discusses the flow of vanadium in the U.S. economy in 2004. This report includes a description of vanadium supply and demand in the United States and illustrates the extent of vanadium recycling and recycling trends. In 2004, apparent vanadium consumption, by end use, in the United States was 3,820 metric tons (t) in steelmaking and 232 t in manufacturing, of which 17 t was for the production of superalloys and 215 t was for the production of other alloys, cast iron, catalysts, and chemicals. Vanadium use in steel is almost entirely dissipative because recovery of vanadium from steel scrap is chemically impeded under the oxidizing conditions in steelmaking furnaces. The greatest amount of vanadium recycling is in the superalloy, other-alloy, and catalyst sectors of the vanadium market. Vanadium-bearing catalysts are associated with hydrocarbon recovery and refining in the oil industry. In 2004, 2,850 t of vanadium contained in alloy scrap and spent catalysts was recycled, which amounted to about 44 percent of U.S. domestic production. About 94 percent of vanadium use in the United States was dissipative (3,820 t in steel/4,050 t in steel+fabricated products).

Comparison of Ultrasound-Assisted and Regular Leaching of Vanadium and Chromium from Roasted High Chromium Vanadium Slag

NASA Astrophysics Data System (ADS)

Wen, Jing; Jiang, Tao; Gao, Huiyang; Liu, Yajing; Zheng, Xiaole; Xue, Xiangxin

2018-02-01

Ultrasound-assisted leaching (UAL) was used for vanadium and chromium leaching from roasted material obtained by the calcification roasting of high-chromium-vanadium slag. UAL was compared with regular leaching. The effect of the leaching time and temperature, acid concentration, and liquid-solid ratio on the vanadium and chromium leaching behaviors was investigated. The UAL mechanism was determined from particle-size-distribution and microstructure analyses. UAL decreased the reaction time and leaching temperature significantly. Furthermore, 96.67% vanadium and less than 1% chromium were leached at 60°C for 60 min with 20% H2SO4 at a liquid-solid ratio of 8, which was higher than the maximum vanadium leaching rate of 90.89% obtained using regular leaching at 80°C for 120 min. Ultrasonic waves broke and dispersed the solid sample because of ultrasonic cavitation, which increased the contact area of the roasted sample and the leaching medium, the solid-liquid mass transfer, and the vanadium leaching rate.

[The vanadium compounds: chemistry, synthesis, insulinomimetic properties].

PubMed

Fedorova, E V; Buriakina, A V; Vorob'eva, N M; Baranova, N I

2014-01-01

The review considers the biological role of vanadium, its participation in various processes in humans and other mammals, and the anti-diabetic effect of its compounds. Vanadium salts have persistent hypoglycemic and antihyperlipidemic effects and reduce the probability of secondary complications in animals with experimental diabetes. The review contains a detailed description of all major synthesized vanadium complexes having antidiabetic activity. Currently, vanadium complexes with organic ligands are more effective and safer than the inorganic salts. Despite the proven efficacy of these compounds as the anti-diabetic agents in animal models, only one organic complex of vanadium is currently under the second phase of clinical trials. All of the considered data suggest that vanadium compound are a new promising class of drugs in modern pharmacotherapy of diabetes.

Huntingtin gene evolution in Chordata and its peculiar features in the ascidian Ciona genus

PubMed Central

Gissi, Carmela; Pesole, Graziano; Cattaneo, Elena; Tartari, Marzia

2006-01-01

Background To gain insight into the evolutionary features of the huntingtin (htt) gene in Chordata, we have sequenced and characterized the full-length htt mRNA in the ascidian Ciona intestinalis, a basal chordate emerging as new invertebrate model organism. Moreover, taking advantage of the availability of genomic and EST sequences, the htt gene structure of a number of chordate species, including the cogeneric ascidian Ciona savignyi, and the vertebrates Xenopus and Gallus was reconstructed. Results The C. intestinalis htt transcript exhibits some peculiar features, such as spliced leader trans-splicing in the 98 nt-long 5' untranslated region (UTR), an alternative splicing in the coding region, eight alternative polyadenylation sites, and no similarities of both 5' and 3'UTRs compared to homologs of the cogeneric C. savignyi. The predicted protein is 2946 amino acids long, shorter than its vertebrate homologs, and lacks the polyQ and the polyP stretches found in the the N-terminal regions of mammalian homologs. The exon-intron organization of the htt gene is almost identical among vertebrates, and significantly conserved between Ciona and vertebrates, allowing us to hypothesize an ancestral chordate gene consisting of at least 40 coding exons. Conclusion During chordate diversification, events of gain/loss, sliding, phase changes, and expansion of introns occurred in both vertebrate and ascidian lineages predominantly in the 5'-half of the htt gene, where there is also evidence of lineage-specific evolutionary dynamics in vertebrates. On the contrary, the 3'-half of the gene is highly conserved in all chordates at the level of both gene structure and protein sequence. Between the two Ciona species, a fast evolutionary rate and/or an early divergence time is suggested by the absence of significant similarity between UTRs, protein divergence comparable to that observed between mammals and fishes, and different distribution of repetitive elements. PMID:17092333

Analysis of the Henze precipitate from the blood cells of the ascidian Phallusia mammillata

NASA Astrophysics Data System (ADS)

Ciancio, Aurelio; Scippa, Silvia; Nette, Geoffrey; De Vincentiis, Mario

The Henze precipitate, a peculiar blue-green microparticulate obtained by lysis of the blood cells of the ascidian Phallusia mammillata (Protochordata), was investigated with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray microanalysis. The precipitate was collected from the Henze solution, an unstable red-brown product obtained by treating blood with distilled water, whose degradation yields a characteristic blue-green product. The microparticulates measured 50-100 µm in diameter and appeared irregular in shape. SEM examination showed smooth, roughly round boundaries. The microparticulate surface examined with AFM appeared as an irregular matrix formed by 70-320-nm-wide mammillate composites, including and embedding small (500-800 nm wide) crystal-like multilayered formations. X- ray analysis showed that the elements present in these same precipitates were mainly C, Si, Al and O. The microparticulate composition appeared close to those of natural waxes or lacquers, embedding amorphous silicates and/or other Si-Al components. The unusual occurrence of Si in ascidian blood and its role are discussed.

Bioleaching of vanadium from barren stone coal and its effect on the transition of vanadium speciation and mineral phase

NASA Astrophysics Data System (ADS)

Wang, Xin; Lin, Hai; Dong, Ying-bo; Li, Gan-yu

2018-03-01

This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial pH value, initial Fe2+ concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield (H2SO4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11wt% greater than the chemical leaching yield. The Community Bureau of Reference (BCR) sequential extraction results revealed that 88.62wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44wt%. The X-ray diffraction (XRD) and Fourier transform infrared (FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.

Memory Deficit Recovery after Chronic Vanadium Exposure in Mice.

PubMed

Folarin, Oluwabusayo; Olopade, Funmilayo; Onwuka, Silas; Olopade, James

2016-01-01

Vanadium is a transitional metal with an ability to generate reactive oxygen species in the biological system. This work was designed to assess memory deficits in mice chronically exposed to vanadium. A total of 132 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three major groups of vanadium treated, matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Animals were tested using Morris water maze and forelimb grip test at 3, 6, 9, and 12 months of age. The results showed that animals across the groups showed no difference in learning but had significant loss in memory abilities after 3 months of vanadium exposure and this trend continued in all vanadium-exposed groups relative to the controls. Animals exposed to vanadium for three months recovered significantly only 9 months after vanadium withdrawal. There was no significant difference in latency to fall in the forelimb grip test between vanadium-exposed groups and the controls in all age groups. In conclusion, we have shown that chronic administration of vanadium in mice leads to memory deficit which is reversible but only after a long period of vanadium withdrawal.

Methods for making lithium vanadium oxide electrode materials

DOEpatents

Schutts, Scott M.; Kinney, Robert J.

2000-01-01

A method of making vanadium oxide formulations is presented. In one method of preparing lithium vanadium oxide for use as an electrode material, the method involves: admixing a particulate form of a lithium compound and a particulate form of a vanadium compound; jet milling the particulate admixture of the lithium and vanadium compounds; and heating the jet milled particulate admixture at a temperature below the melting temperature of the admixture to form lithium vanadium oxide.

Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

NASA Astrophysics Data System (ADS)

Natalio, Filipe; André, Rute; Hartog, Aloysius F.; Stoll, Brigitte; Jochum, Klaus Peter; Wever, Ron; Tremel, Wolfgang

2012-08-01

Marine biofouling--the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls--is an expensive problem that is currently without an environmentally compatible solution. Biofouling leads to increased hydrodynamic drag, which, in turn, causes increased fuel consumption and greenhouse gas emissions. Tributyltin-free antifouling coatings and paints based on metal complexes or biocides have been shown to efficiently prevent marine biofouling. However, these materials can damage the environment through metal leaching (for example, of copper and zinc) and bacteria resistance. Here, we show that vanadium pentoxide nanowires act like naturally occurring vanadium haloperoxidases to prevent marine biofouling. In the presence of bromide ions and hydrogen peroxide, the nanowires catalyse the oxidation of bromide ions to hypobromous acid (HOBr). Singlet molecular oxygen (1O2) is formed and this exerts strong antibacterial activity, which prevents marine biofouling without being toxic to marine biota. Vanadium pentoxide nanowires have the potential to be an alternative approach to conventional anti-biofouling agents.

Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi.

PubMed

Niwano, Tomoko; Takatori, Naohito; Kumano, Gaku; Nishida, Hiroki

2009-08-25

In the embryos of various animals, the body elongates after gastrulation by morphogenetic movements involving convergent extension. The Wnt/PCP (planar cell polarity) pathway plays roles in this process, particularly mediolateral polarization and intercalation of the embryonic cells. In ascidians, several factors in this pathway, including Wnt5, have been identified and found to be involved in the intercalation process of notochord cells. In the present study, the role of the Wnt5 genes, Hr-Wnt5alpha (Halocynthia roretzi Wnt5alpha) and Hr-Wnt5beta, in convergent extension was investigated in the ascidian H. roretzi by injecting antisense oligonucleotides and mRNAs into single precursor blastomeres of various tissues, including notochord, at the 64-cell stage. Hr-Wnt5alpha is expressed in developing notochord and was essential for notochord morphogenesis. Precise quantitative control of its expression level was crucial for proper cell intercalation. Overexpression of Wnt5 proteins in notochord and other tissues that surround the notochord indicated that Wnt5alpha plays a role within the notochord, and is unlikely to be the source of polarizing cues arising outside the notochord. Detailed mosaic analysis of the behaviour of individual notochord cells overexpressing Wnt5alpha indicated that a Wnt5alpha-manipulated cell does not affect the behaviour of neighbouring notochord cells, suggesting that Wnt5alpha works in a cell-autonomous manner. This is further supported by comparison of the results of Wnt5alpha and Dsh (Dishevelled) knockdown experiments. In addition, our results suggest that the Wnt/PCP pathway is also involved in mediolateral intercalation of cells of the ventral row of the nerve cord (floor plate) and the endodermal strand. The present study highlights the role of the Wnt5alpha signal in notochord convergent extension movements in ascidian embryos. Our results raise the novel possibility that Wnt5alpha functions in a cell-autonomous manner in

Memory Deficit Recovery after Chronic Vanadium Exposure in Mice

PubMed Central

Folarin, Oluwabusayo; Olopade, Funmilayo; Onwuka, Silas; Olopade, James

2016-01-01

Vanadium is a transitional metal with an ability to generate reactive oxygen species in the biological system. This work was designed to assess memory deficits in mice chronically exposed to vanadium. A total of 132 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three major groups of vanadium treated, matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Animals were tested using Morris water maze and forelimb grip test at 3, 6, 9, and 12 months of age. The results showed that animals across the groups showed no difference in learning but had significant loss in memory abilities after 3 months of vanadium exposure and this trend continued in all vanadium-exposed groups relative to the controls. Animals exposed to vanadium for three months recovered significantly only 9 months after vanadium withdrawal. There was no significant difference in latency to fall in the forelimb grip test between vanadium-exposed groups and the controls in all age groups. In conclusion, we have shown that chronic administration of vanadium in mice leads to memory deficit which is reversible but only after a long period of vanadium withdrawal. PMID:26962395

Neurula rotation determines left-right asymmetry in ascidian tadpole larvae.

PubMed

Nishide, Kazuhiko; Mugitani, Michio; Kumano, Gaku; Nishida, Hiroki

2012-04-01

Tadpole larvae of the ascidian Halocynthia roretzi show morphological left-right asymmetry. The tail invariably bends towards the left side within the vitelline membrane. The structure of the larval brain is remarkably asymmetric. nodal, a conserved gene that shows left-sided expression, is also expressed on the left side in H. roretzi but in the epidermis unlike in vertebrates. We show that nodal signaling at the late neurula stage is required for stereotypic morphological left-right asymmetry at later stages. We uncover a novel mechanism to break embryonic symmetry, in which rotation of whole embryos provides the initial cue for left-sided expression of nodal. Two hours prior to the onset of nodal expression, the neurula embryo rotates along the anterior-posterior axis in a counterclockwise direction when seen in posterior view, and then this rotation stops when the left side of the embryo is oriented downwards. It is likely that epidermis monocilia, which appear at the neurula rotation stage, generate the driving force for the rotation. When the embryo lies on the left side, protrusion of the neural fold physically prevents it from rotating further. Experiments in which neurula rotation is perturbed by various means, including centrifugation and sandwiching between glass, indicate that contact of the left epidermis with the vitelline membrane as a consequence of neurula rotation promotes nodal expression in the left epidermis. We suggest that chemical, and not mechanical, signals from the vitelline membrane promote nodal expression. Neurula rotation is also conserved in other ascidian species.

Reactions of sulfur dioxide with neutral vanadium oxide clusters in the gas phase. I. Density functional theory study.

PubMed

Jakubikova, Elena; Bernstein, Elliot R

2007-12-27

Thermodynamics of reactions of vanadium oxide clusters with SO2 are studied at the BPW91/LANL2DZ level of theory. BPW91/LANL2DZ is insufficient to properly describe relative V-O and S-O bond strengths of vanadium and sulfur oxides. Calibration of theoretical results with experimental data is necessary to compute reliable enthalpy changes for reactions between VxOy and SO2. Theoretical results indicate SO2 to SO conversion occurs for oxygen-deficient clusters and SO2 to SO3 conversion occurs for oxygen-rich clusters. Stable intermediate structures of VOy (y = 1 - 4) clusters with SO2 are also obtained at the BPW91/TZVP level of theory. Some possible mechanisms for SO3 formation and catalyst regeneration for condensed-phase systems are suggested. These results are in agreement with, and complement, gas-phase experimental studies of neutral vanadium oxide clusters.

The role of vanadium in biology.

PubMed

Rehder, Dieter

2015-05-01

Vanadium is special in at least two respects: on the one hand, the tetrahedral anion vanadate(v) is similar to the phosphate anion; vanadate can thus interact with various physiological substrates that are otherwise functionalized by phosphate. On the other hand, the transition metal vanadium can easily expand its sphere beyond tetrahedral coordination, and switch between the oxidation states +v, +iv and +iii in a physiological environment. The similarity between vanadate and phosphate may account for the antidiabetic potential of vanadium compounds with carrier ligands such as maltolate and picolinate, and also for vanadium's mediation in cardiovascular and neuronal defects. Other potential medicinal applications of more complex vanadium coordination compounds, for example in the treatment of parasitic tropical diseases, may also be rooted in the specific properties of the ligand sphere. The ease of the change in the oxidation state of vanadium is employed by prokarya (bacteria and cyanobacteria) as well as by eukarya (algae and fungi) in respiratory and enzymatic functions. Macroalgae (seaweeds), fungi, lichens and Streptomyces bacteria have available haloperoxidases, and hence enzymes that enable the 2-electron oxidation of halide X(-) with peroxide, catalyzed by a Lewis-acidic V(V) center. The X(+) species thus formed can be employed to oxidatively halogenate organic substrates, a fact with implications also for the chemical processes in the atmosphere. Vanadium-dependent nitrogenases in bacteria (Azotobacter) and cyanobacteria (Anabaena) convert N2 + H(+) to NH4(+) + H2, but are also receptive for alternative substrates such as CO and C2H2. Among the enigmas to be solved with respect to the utilization of vanadium in nature is the accumulation of V(III) by some sea squirts and fan worms, as well as the purport of the nonoxido V(IV) compound amavadin in the fly agaric.

Formation, structure and bond dissociation thresholds of gas-phase vanadium oxide cluster ions

NASA Astrophysics Data System (ADS)

Bell, R. C.; Zemski, K. A.; Justes, D. R.; Castleman, A. W.

2001-01-01

The formation and structure of gas-phase vanadium oxide cluster anions are examined using a guided ion beam mass spectrometer coupled with a laser vaporization source. The dominant peaks in the anion total mass distribution correspond to clusters having stoichiometries of the form (VO2)n(VO3)m(O2)q-. Collision-induced dissociation studies of the vanadium oxide species V2O4-6-, V3O6-9-, V4O8-10-, V5O11-13-, V6O13-15-, and V7O16-18- indicate that VO2, VO3, and V2O5 units are the main building blocks of these clusters. There are many similarities between the anion mass distribution and that of the cation distribution studied previously. The principal difference is a shift to higher oxygen content by one additional oxygen atom for the stoichiometric anions (VxOy-) as compared to the cations with the same number of vanadium atoms, which is attributed to the extra pair of electrons of the anionic species. The oxygen-rich clusters, VxOy(O2)-, are shown to more tightly adsorb molecular oxygen than those of the corresponding cationic clusters. In addition, the bond dissociation thresholds for the vanadium oxide clusters ΔE(V+-O)=6.09±0.28 eV, ΔE(OV+-O)=3.51±0.36 eV, and ΔE(O2V--O)=5.43±0.31 eV are determined from the energy-dependent collision-induced dissociation cross sections with Xe as the collision partner. To the best of our knowledge, this is the first bond dissociation energy reported for the breaking of the V-O bond of a vanadium oxide anion.

The role of phosphate additive in stabilization of sulphuric-acid-based vanadium(V) electrolyte for all-vanadium redox-flow batteries

NASA Astrophysics Data System (ADS)

Roznyatovskaya, Nataliya V.; Roznyatovsky, Vitaly A.; Höhne, Carl-Christoph; Fühl, Matthias; Gerber, Tobias; Küttinger, Michael; Noack, Jens; Fischer, Peter; Pinkwart, Karsten; Tübke, Jens

2017-09-01

Catholyte in all-vanadium redox-flow battery (VRFB) which consists of vanadium salts dissolved in sulphuric acid is known to be stabilized by phosphoric acid to slow down the thermal aging at temperatures higher than 40 °C. To reveal the role of phosphoric acid, the thermally-induced aggregation is investigated using variable-temperature 51V, 31P, 17O, 1H nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS). The results indicate that the thermal stabilization of vanadium(V) electrolyte is attained by the involvement of monomeric and dimeric vanadium(V) species in the reaction with phosphoric acid which is concurrent to the formation of neutral hydroxo-aqua vanadium(V) precipitation precursor. The dimers are stabilized by counter ions due to association reaction or if such stabilization is not possible, precipitation of vanadium pentoxide is favored. The evolution of particles size distributions at 50 °C in electrolyte samples containing 1.6 M vanadium and 4.0 M total sulphate and the pathways of precipitate formation are discussed. The optimal total phosphate concentration is found to be of 0.15 M. However, the induction time is assumed to be dependent not only on the total phosphate concentrations, but also on the ratio of total vanadium(V) to sulphate concentrations.

Mineral resource of the month: vanadium

USGS Publications Warehouse

Magyar, Michael J.

2007-01-01

Vanadium, the name of which comes from Vanadis, a goddess in Scandinavian mythology, is one of the most important ferrous metals. Vanadium has many uses, but the metal’s metallurgical applications, such as an alloying element in iron and steel, account for more than 85 percent of U.S. consumption. The dominant nonmetallurgical use of the metal is as a catalyst for the production of maleic anhydride and sulfuric acid, ceramics, vanadium chemicals and electronics.

A novel process for recovery of iron, titanium, and vanadium from titanomagnetite concentrates: NaOH molten salt roasting and water leaching processes.

PubMed

Chen, Desheng; Zhao, Longsheng; Liu, Yahui; Qi, Tao; Wang, Jianchong; Wang, Lina

2013-01-15

A novel process for recovering iron, titanium, and vanadium from titanomagnetite concentrates has been developed. In the present paper, the treatment of rich titanium-vanadium slag by NaOH molten salt roasting and water leaching processes is investigated. In the NaOH molten salt roasting process, the metallic iron is oxidized into ferriferous oxide, MgTi(2)O(5) is converted to NaCl-type structure of Na(2)TiO(3), and M(3)O(5) (M=Ti, Mg, Fe) is converted to α-NaFeO(2)-type structure of NaMO(2), respectively. Roasting temperature and NaOH-slag mass ratio played a considerable role in the conversion of titanium in the rich titanium-vanadium slag during the NaOH molten salt roasting process. Roasting at 500 °C for 60 min and a 1:1 NaOH-slag mass ratio produces 96.3% titanium conversion. In the water leaching process, the Na(+) was exchanged with H(+), Na(2)TiO(3) is converted to undefined structure of H(2)TiO(3), and NaMO(2) is converted to α-NaFeO(2)-type structure of HMO(2). Under the optimal conditions, 87.3% of the sodium, 42.3% of the silicon, 43.2% of the aluminum, 22.8% of the manganese, and 96.6% of the vanadium are leached out. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

A combined theoretical-experimental study of interactions between vanadium ions and Nafion membrane in all-vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Intan, Nadia N.; Klyukin, Konstantin; Zimudzi, Tawanda J.; Hickner, Michael A.; Alexandrov, Vitaly

2018-01-01

Vanadium redox flow batteries (VRFBs) are a promising solution for large-scale energy storage, but a number of problems still impede the deployment of long-lifetime VRFBs. One important aspect of efficient operation of VRFBs is understanding interactions between vanadium species and the membrane. Herein, we investigate the interactions between all four vanadium cations and Nafion membrane by a combination of infrared (IR) spectroscopy and density-functional-theory (DFT)-based static and molecular dynamics simulations. It is observed that vanadium species primarily lead to changes in the IR spectrum of Nafion in the SO3- spectral region which is attributed to the interaction between vanadium species and the SO3- exchange sites. DFT calculations of vanadium -Nafion complexes in the gas phase show that it is thermodynamically favorable for all vanadium cations to bind to SO3- via a contact pair mechanism. Car-Parrinello molecular dynamics-based metadynamics simulations of cation-Nafion systems in aqueous solution suggest that V2+ and V3+ species coordinate spontaneously to SO3-, which is not the case for VO2+ and VO2+ . The interaction behavior of the uncycled membrane determined in this study is used to explain the experimentally observed changes in the vibrational spectra, and is discussed in light of previous results on device-cycled membranes.

Effective Recovery of Vanadium from Oil Refinery Waste into Vanadium-Based Metal-Organic Frameworks.

PubMed

Zhan, Guowu; Ng, Wei Cheng; Lin, Wenlin Yvonne; Koh, Shin Nuo; Wang, Chi-Hwa

2018-03-06

Carbon black waste, an oil refinery waste, contains a high concentration of vanadium(V) leftover from the processing of crude oil. For the sake of environmental sustainability, it is therefore of interest to recover the vanadium as useful products instead of disposing of it. In this work, V was recovered in the form of vanadium-based metal-organic frameworks (V-MOFs) via a novel pathway by using the leaching solution of carbon black waste instead of commercially available vanadium chemicals. Two different types of V-MOFs with high levels of crystallinity and phase purity were fabricated in very high yields (>98%) based on a coordination modulation method. The V-MOFs exhibited well-defined and controlled shapes such as nanofibers (length: > 10 μm) and nanorods (length: ∼270 nm). Furthermore, the V-MOFs showed high catalytic activities for the oxidation of benzyl alcohol to benzaldehyde, indicating the strong potential of the waste-derived V-MOFs in catalysis applications. Overall, our work offers a green synthesis pathway for the preparation of V-MOFs by using heavy metals of industrial waste as the metal source.

Effect of substrate temperature on thermochromic vanadium dioxide thin films sputtered from vanadium target

NASA Astrophysics Data System (ADS)

Madiba, I. G.; Kotsedi, L.; Ngom, B. D.; Khanyile, B. S.; Maaza, M.

2018-05-01

Vanadium dioxide films have been known as the most promising thermochromic thin films for smart windows which self-control the solar radiation and heat transfer for energy saving, comfort in houses and automotives. Such an attractive technological application is due to the fact that vanadium dioxide crystals exhibit a fast semiconductor-to-metal phase transition at a transition temperature Tc of about 68 °C, together with sharp optical changes from high transmitive to high reflective coatings in the IR spectral region. The phase transition has been associated with the nature of the microstructure, stoichiometry and stresses related to the oxide. This study reports on the effect of the crystallographic quality controlled by the substrate temperature on the thermochromic properties of vanadium dioxide thin films synthesized by reactive radio frequency inverted cylindrical magnetron sputtering from vanadium target. The reports results are based on X-ray diffraction, Atomic force microscopy, and UV-Visible spectrophotometer. The average crystalline grain size of VO2 increases with the substrate temperature, inducing stress related phenomena within the films.

Microbial vanadium (V) reduction in groundwater with different soils from vanadium ore mining areas.

PubMed

Hao, Liting; Zhang, Baogang; Feng, Chuanping; Zhang, Zhenya; Lei, Zhongfang; Shimizu, Kazuya; Cao, Xuelong; Liu, Hui; Liu, Huipeng

2018-07-01

This work investigated the potential of vanadium (V) (V(V)) bioreduction by using soils sampled from four main kinds of vanadium ore mining areas, i.e. vanadium titanomagnetite, stone coal, petroleum associated minerals and uvanite as inocula. During a typical operation cycle of 60 h, the soils from vanadium titanomagnetite area and petroleum associated minerals area exhibited higher V(V) removal efficiencies, about 92.0 ± 2.0% and 91.0 ± 1.9% in comparison to 87.1 ± 1.9% and 69.0 ± 1.1% for the soils from uvanite and stone coal areas, respectively. Results from high-throughput 16 S rRNA gene pyrosequencing analysis reflect the accumulation of Bryobacter and Acidobacteriaceae with capabilities of V(V) reduction, accompanied with other functional species. This study is helpful to search new functional species for V(V) reduction and to develop in situ bioremediations of V(V) polluted groundwater. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method for preparing high purity vanadium

DOEpatents

Schmidt, Frederick; Carlson, O. Norman

1986-09-09

A method for preparing high purity vanadium having a low silicon content has been developed. Vanadium pentoxide is reduced with a stoichiometric, or slightly deficient amount of aluminum to produce a vanadium-aluminum alloy containing an excess of oxygen. Silicon is removed by electron-beam melting the alloy under oxidizing conditions to promote the formation of SiO which is volatile at elevated temperatures. Excess oxygen is removed by heating the alloy in the presence of calcium metal to form calcium oxide.

Method for preparing high purity vanadium

DOEpatents

Schmidt, F.; Carlson, O.N.

1984-05-16

A method for preparing high purity vanadium having a low silicon content has been developed. Vanadium pentoxide is reduced with a stoichiometric, or slightly deficient amount of aluminum to produce a vanadium-aluminum alloy containing an excess of oxygen. Silicon is removed by electron-beam melting the alloy under oxidizing conditions to promote the formation of SiO which is volatile at elevated temperatures. Excess oxygen is removed by heating the alloy in the presence of calcium metal to form calcium oxide.

Vanadium K-edge XAS studies on the native and peroxo-forms of vanadium chloroperoxidase from Curvularia inaequalis.

PubMed

Renirie, Rokus; Charnock, John M; Garner, C David; Wever, Ron

2010-06-01

Vanadium K-edge X-ray Absorption Spectra have been recorded for the native and peroxo-forms of vanadium chloroperoxidase from Curvularia inaequalis at pH 6.0. The Extended X-ray Absorption Fine Structure (EXAFS) regions provide a refinement of previously reported crystallographic data; one short V=O bond (1.54A) is present in both forms. For the native enzyme, the vanadium is coordinated to two other oxygen atoms at 1.69A, another oxygen atom at 1.93A and the nitrogen of an imidazole group at 2.02A. In the peroxo-form, the vanadium is coordinated to two other oxygen atoms at 1.67A, another oxygen atom at 1.88A and the nitrogen of an imidazole group at 1.93A. When combined with the available crystallographic and kinetic data, a likely interpretation of the EXAFS distances is a side-on bound peroxide involving V-O bonds of 1.67 and 1.88A; thus, the latter oxygen would be 'activated' for transfer. The shorter V-N bond observed in the peroxo-form is in line with the previously reported stronger binding of the cofactor in this form of the enzyme. Reduction of the enzyme with dithionite has a clear influence on the spectrum, showing a change from vanadium(V) to vanadium(IV).

Organic matter diagenesis as the key to a unifying theory for the genesis of tabular uranium-vanadium deposits in the Morrison Formation, Colorado Plateau

USGS Publications Warehouse

Hansley, P.L.; Spirakis, C.S.

1992-01-01

Interstitial, epigenetic amorphous organic matter is intimately associated with uranium in the Grants uranium region and is considered essential to genetic models for these deposits. In contrast, uranium minerals are intimately associated with authigenic vanadium chlorite and vanadium oxides in amorphous organic matter-poor ores of the Slick Rock and Henry Mountains mining districts and therefore, in some genetic models amorphous organic matter is not considered crucial to the formation of these deposits. Differences in organic matter content can be explained by recognizing that amorphous organic matter-poor deposits have been subjected to more advanced stages of diagenesis than amorphous organic matter-rich deposits. Evidence that amorphous organic matter was involved in the genesis of organic matter-poor, as well as organic matter-rich, deposits is described. -from Authors

Roasting and leaching behaviors of vanadium and chromium in calcification roasting-acid leaching of high-chromium vanadium slag

NASA Astrophysics Data System (ADS)

Wen, Jing; Jiang, Tao; Zhou, Mi; Gao, Hui-yang; Liu, Jia-yi; Xue, Xiang-xin

2018-05-01

Calcification roasting-acid leaching of high-chromium vanadium slag (HCVS) was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium. The effects of the purity of CaO, molar ratio between CaO and V2O5 ( n(CaO)/ n(V2O5)), roasting temperature, holding time, and the heating rate used in the oxidation-calcification processes were investigated. The roasting process and mechanism were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry-differential scanning calorimetry (TG-DSC). The results show that most of vanadium reacted with CaO to generate calcium vanadates and transferred into the leaching liquid, whereas almost all of the chromium remained in the leaching residue in the form of (Fe0.6Cr0.4)2O3. Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with CaO. Moreover, CaO was more likely to combine with vanadium, as further confirmed by thermodynamic analysis. When the HCVS with CaO added in an n(CaO)/ n(V2O5) ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min, the leaching ratios of vanadium and chromium reached 91.14% and 0.49%, respectively; thus, efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium. Furthermore, the oxidation and calcification reactions of the spinel phases occurred at 592 and 630°C for n(CaO)/ n(V2O5) ratios of 0.5 and 5, respectively.

Exploring electrolyte preference of vanadium nitride supercapacitor electrodes

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

Wang, Bo; Chen, Zhaohui; Lu, Gang

Highlights: • Hierarchical VN nanostructures were prepared on graphite foam. • Electrolyte preference of VN supercapacitor electrodes was explored. • VN showed better capacitive property in organic and alkaline electrolytes than LiCl. - Abstract: Vanadium nitride hierarchical nanostructures were prepared through an ammonia annealing procedure utilizing vanadium pentoxide nanostructures grown on graphite foam. The electrochemical properties of hierarchical vanadium nitride was tested in aqueous and organic electrolytes. As a result, the vanadium nitride showed better capacitive energy storage property in organic and alkaline electrolytes. This work provides insight into the charge storage process of vanadium nitride and our findings canmore » shed light on other transition metal nitride-based electrochemical energy storage systems.« less

A well-defined terminal vanadium(III) oxo complex.

PubMed

King, Amanda E; Nippe, Michael; Atanasov, Mihail; Chantarojsiri, Teera; Wray, Curtis A; Bill, Eckhard; Neese, Frank; Long, Jeffrey R; Chang, Christopher J

2014-11-03

The ubiquity of vanadium oxo complexes in the V+ and IV+ oxidation states has contributed to a comprehensive understanding of their electronic structure and reactivity. However, despite being predicted to be stable by ligand-field theory, the isolation and characterization of a well-defined terminal mononuclear vanadium(III) oxo complex has remained elusive. We present the synthesis and characterization of a unique terminal mononuclear vanadium(III) oxo species supported by the pentadentate polypyridyl ligand 2,6-bis[1,1-bis(2-pyridyl)ethyl]pyridine (PY5Me2). Exposure of [V(II)(NCCH3)(PY5Me2)](2+) (1) to either dioxygen or selected O-atom-transfer reagents yields [V(IV)(O)(PY5Me2)](2+) (2). The metal-centered one-electron reduction of this vanadium(IV) oxo complex furnishes a stable, diamagnetic [V(III)(O)(PY5Me2)](+) (3) species. The vanadium(III) oxo species is unreactive toward H- and O-atom transfer but readily reacts with protons to form a putative vanadium hydroxo complex. Computational results predict that further one-electron reduction of the vanadium(III) oxo species will result in ligand-based reduction, even though pyridine is generally considered to be a poor π-accepting ligand. These results have implications for future efforts toward low-valent vanadyl chemistry, particularly with regard to the isolation and study of formal vanadium(II) oxo species.

Oxidation States of Grim Glasses in EET79001 Based on Vanadium Valence

NASA Technical Reports Server (NTRS)

Sutton, S. R.; Rao, M. N.; Nyquist, L. E.

2010-01-01

Gas-rich impact-melt (GRIM) glasses in SNC meteorites are very rich in Martian atmospheric noble gases and sulfur suggesting a possible occurrence of regolith-derived secondary mineral assemblages in these samples. Previously, we have studied two GRIM glasses, 506 and 507, from EET79001 Lith A and Lith B, respectively, for elemental abundances and spatial distribution of sulfur using EMPA (WDS) and FE-SEM (EDS) techniques and for sulfur-speciation using K-edge XANES techniques. These elemental and FE-SEM micro-graph data at several locations in the GRIM glasses from Shergotty (DBS), Zagami 994 and EET79001, Lith B showed that FeO and SO3 are positively correlated (SO3 represents a mixture of sulfide and sulfate). FE-SEM (EDS) study revealed that the sulfur-rich pockets in these glasses contain numerous micron-sized iron-sulfide (Fe-S) globules sequestered throughout the volume. However, in some areas (though less frequently), we detected significant Fe-S-O signals suggesting the occurrence of iron sulfate. These GRIM glasses were studied by K-edge microXANES techniques for sulfur speciation in association with iron in sulfur-rich areas. In both samples, we found the sulfur speciation dominated by sulfide with minor oxidized sulfur mixed in with various proportions. The abundance of oxidized sulfur was greater in 506 than in 507. Based on these results, we hypothesize that sulfur initially existed as sulfate in the glass precursor materials and, on shock-impact melting of the precursor materials producing these glasses, the oxidized sulfur was reduced to predominately sulfide. In order to further test this hypothesis, we have used microXANES to measure the valence states of vanadium in GRIM glasses from Lith A and Lith B to complement and compare with previous analogous measurements on Lith C (note: 506 and 507 contain the largest amounts of martian atmospheric gases but the gas-contents in Lith C measured by are unknown). Vanadium is ideal for addressing this re

New GlcNAc/GalNAc-specific lectin from the ascidian Didemnum ternatanum.

PubMed

Molchanova, Valentina; Chikalovets, Irina; Li, Wei; Kobelev, Stanislav; Kozyrevskaya, Svetlana; Bogdanovich, Raisa; Howard, Eric; Belogortseva, Natalia

2005-05-25

Previously we isolated GlcNAc-specific lectin (DTL) from the ascidian Didemnum ternatanum by affinity chromatography on cross-linked ovalbumin. Here we report the purification and characterization of new D-GlcNAc/D-GalNAc-specific lectin DTL-A from the same ascidian. This lectin was isolated from non-bound cross-linked ovalbumin fraction and further was purified by gel filtration on Sepharose CL-4B, affinity chromatography on GlcNAc-agarose and gel filtration on Superdex 200. SDS-polyacrylamide gel electrophoresis and gel filtration of purified lectin on Sepharose CL-4B indicates that it exists as large aggregates in the native state. Investigations of the carbohydrate specificity of DTL-A by enzyme-linked lectin assay suggest the multi-specificity of this lectin. DTL-A binds BSM, asialo-BSM as well as heparin and dextran sulfate. The binding of DTL-A to BSM was inhibited by monosaccharides D-GlcNAc and D-GalNAc, their alpha- but not beta-anomers. Among polysaccharides and glycoconjugates, DTL-A binding to BSM was effectively inhibited by BSM, asialo-BSM, pronase-treated BSM and synthetic alpha-D-GalNAc-PAA. Fetuin and asialofetuin showed a much lower inhibitory potency, heparin and dextran sulfate were noninhibitory. On the other hand, DTL-A binding to heparin was effectively inhibited by dextran sulfate, fucoidan, whereas BSM showed insignificantly inhibitory effect. DTL-A binding to heparin was not inhibited by D-GlcNAc and D-GalNAc.

Vanadium K Xanes Studies of EET79001 Impact-Melt Glasses Revisited

NASA Technical Reports Server (NTRS)

Sutton, S. R.; Rao, M. N.; Nyquist, L. E.; Ross, D. K.

2016-01-01

Some impact-melt glasses in shergottites are rich in Martian atmospheric noble gases and sulfur suggesting a possible association with regolith-derived secondary mineral assemblages in the shocked samples. Previously, we studied two glasses, # 506 (Lith C in Lith A) and # 507 (Lith C in Lith B) from EET79001 [1,2] and suggested that sulfur initially existed as sulfate in the glass precursor materials and, on shock-melting of the precursors, the sulfate was reduced to sulfides in the shock glasses. To examine the validity of this hypothesis, we used V K microXANES techniques to measure the valence states of vanadium in the Lith C glasses from Lith A and Lith B in EET79001 [3] to complement and com-pare with previous analogous measurements on,78 glass (Lith C in Lith A) [4,5]. We reported the preliminary results in [3]. Vanadium is ideal for addressing the redox issue because it has multiple valence states and is a well-studied element. Vanadium in basalts exists mostly as V(sup 3+), V(sup 4+) and V(sup 5+) in terrestrial samples, mainly as V(sup 3+) with minor V(sup 2+) and minor V(sup 4+) in lunar samples and as roughly equal mixtures of V(sup 3+) and V(sup 4+) in Martian meteorites. In this report, we discuss the application of the V K XANES results to decipher the nature of shock reduction occurring in the silicate glasses during the impact process.

Mineralogy and Geochemistry of Vanadium-Bearing Black Shales at Zhangcun and Zhengfang, Eastern Jiangxi Province, China

NASA Astrophysics Data System (ADS)

Long, H.; Long, H.; Nekvasil, H.; Liu, Y.

2001-12-01

As a member of Hetang Formation, lower Cambrian, the Zhangcun-Zhengfang vanadium-bearing black shales are spread in the sea basin outside of the Ancient Jiangnan Island Arc. The composition of black shales is silicalite + siltstone + detrital carbonate. A large amount of hyalophane has been discovered in the shales and the hyalophane-rich rock is the major type of vanadium-host rock. The barium content in the hyalophane is up to 18.91%. The vanadium mainly exists in vanadiferous illite and several Ti-V oxides, possibly including a new mineral. The chemical formula of this kind of Ti-V oxide is V2O3¡nTiO2, n=4¡ª9, according to the electronic microprobe studies. The micro X-ray diffraction studies show the new mineral may be triclinic. The shales are rich in Ba, K, V and contain only trace Na and Mn while all the compositions of the shales except carbonate have a low content of Mg and Ca. According to the authors¡_ study, V obviously has a relationship with Ba and Se, which are from the volcano or hydrothermal activities, and the basic elements Cr, Co, Ni, Ti and Fe. It may present that they are from the same source. Thus, it seems that they are not from the ¡rnormal¡_ sedimentary environment and may be from the hydrothermal deposition. The REE models show that silicalite may be the hydrothermal deposit that does not mix with seawater while the REE models of hyalopahne-rich rock is similar to some modern hydrothermal deposits in the seafloor. The subtle negative anomaly of Yb may reflect the REE model of basalt in the seafloor. The geology and geochemistry of the shales indicate that the shales may be of hydrothermal genesis. Silicalite may be the typical ¡r pure¡_ hydrothermal sediment and hyalophane-rich rock may be the product of hydrothermal activity while the hydrothermal fluid passes the continent source material in the sedimentary process. V, Ti, Ba and Si may be from the volcanic rock in the seafloor and the Al and K may be from the continent.

Nitric oxide acts as a positive regulator to induce metamorphosis of the ascidian Herdmania momus.

PubMed

Ueda, Nobuo; Degnan, Sandie M

2013-01-01

Marine invertebrates commonly have a biphasic life cycle in which the metamorphic transition from a pelagic larva to a benthic post-larva is mediated by the nitric oxide signalling pathway. Nitric oxide (NO) is synthesised by nitric oxide synthase (NOS), which is a client protein of the molecular chaperon heat shock protein 90 (HSP90). It is notable, then, that both NO and HSP90 have been implicated in regulating metamorphosis in marine invertebrates as diverse as urochordates, echinoderms, molluscs, annelids, and crustaceans. Specifically, the suppression of NOS activity by the application of either NOS- or HSP90-inhibiting pharmacological agents has been shown consistently to induce the initiation of metamorphosis, leading to the hypothesis that a negative regulatory role of NO is widely conserved in biphasic life cycles. Further, the induction of metamorphosis by heat-shock has been demonstrated for multiple species. Here, we investigate the regulatory role of NO in induction of metamorphosis of the solitary tropical ascidian, Herdmania momus. By coupling pharmacological treatments with analysis of HmNOS and HmHSP90 gene expression, we present compelling evidence of a positive regulatory role for NO in metamorphosis of this species, in contrast to all existing ascidian data that supports the hypothesis of NO as a conserved negative regulator of metamorphosis. The exposure of competent H. momus larvae to a NOS inhibitor or an NO donor results in an up-regulation of NOS and HSP90 genes. Heat shock of competent larvae induces metamorphosis in a temperature dependent manner, up to a thermal tolerance that approaches 35°C. Both larval/post-larval survival and the appearance of abnormal morphologies in H. momus post-larvae reflect the magnitude of up-regulation of the HSP90 gene in response to heat-shock. The demonstrated role of NO as a positive metamorphic regulator in H. momus suggests the existence of inter-specific adaptations of NO regulation in ascidian

Expression of an Msx homeobox gene in ascidians: insights into the archetypal chordate expression pattern.

PubMed

Ma, L; Swalla, B J; Zhou, J; Dobias, S L; Bell, J R; Chen, J; Maxson, R E; Jeffery, W R

1996-03-01

The Msx homeobox genes are expressed in complex patterns during vertebrate development in conjunction with inductive tissue interactions. As a means of understanding the archetypal role of Msx genes in chordates, we have isolated and characterized an Msx gene in ascidians, protochordates with a relatively simple body plan. The Mocu Msx-a and McMsx-a genes, isolated from the ascidians Molgula oculata and Molgula citrina, respectively, have homeodomains that place them in the msh-like subclass of Msx genes. Therefore, the Molgula Msx-a genes are most closely related to the msh genes previously identified in a number of invertebrates. Southern blot analysis suggests that there are one or two copies of the Msx-a gene in the Molgula genome. Northern blot and RNase protection analysis indicate that Msx-a transcripts are restricted to the developmental stages of the life cycle. In situ hybridization showed that Msx-a mRNA first appears just before gastrulation in the mesoderm (presumptive notochord and muscle) and ectoderm (neural plate) cells. Transcript levels decline in mesoderm cells after the completion of gastrulation, but are enhanced in the folding neural plate during neurulation. Later, Msx-a mRNA is also expressed in the posterior ectoderm and in a subset of the tail muscle cells. The ectoderm and mesoderm cells that express Msx-a are undergoing morphogenetic movements during gastrulation, neurulation, and tail formation. Msx-a expression ceases after these cells stop migrating. The ascidian M. citrina, in which adult tissues and organs begin to develop precociously in the larva, was used to study Msx-a expression during adult development. Msx-a transcripts are expressed in the heart primordium and the rudiments of the ampullae, epidermal protrusions with diverse functions in the juvenile. The heart and ampullae develop in regions where mesenchyme cells interact with endodermal or epidermal epithelia. A comparison of the expression patterns of the Molgula genes

Nitric Oxide Acts as a Positive Regulator to Induce Metamorphosis of the Ascidian Herdmania momus

PubMed Central

Ueda, Nobuo; Degnan, Sandie M.

2013-01-01

Marine invertebrates commonly have a biphasic life cycle in which the metamorphic transition from a pelagic larva to a benthic post-larva is mediated by the nitric oxide signalling pathway. Nitric oxide (NO) is synthesised by nitric oxide synthase (NOS), which is a client protein of the molecular chaperon heat shock protein 90 (HSP90). It is notable, then, that both NO and HSP90 have been implicated in regulating metamorphosis in marine invertebrates as diverse as urochordates, echinoderms, molluscs, annelids, and crustaceans. Specifically, the suppression of NOS activity by the application of either NOS- or HSP90-inhibiting pharmacological agents has been shown consistently to induce the initiation of metamorphosis, leading to the hypothesis that a negative regulatory role of NO is widely conserved in biphasic life cycles. Further, the induction of metamorphosis by heat-shock has been demonstrated for multiple species. Here, we investigate the regulatory role of NO in induction of metamorphosis of the solitary tropical ascidian, Herdmania momus. By coupling pharmacological treatments with analysis of HmNOS and HmHSP90 gene expression, we present compelling evidence of a positive regulatory role for NO in metamorphosis of this species, in contrast to all existing ascidian data that supports the hypothesis of NO as a conserved negative regulator of metamorphosis. The exposure of competent H. momus larvae to a NOS inhibitor or an NO donor results in an up-regulation of NOS and HSP90 genes. Heat shock of competent larvae induces metamorphosis in a temperature dependent manner, up to a thermal tolerance that approaches 35°C. Both larval/post-larval survival and the appearance of abnormal morphologies in H. momus post-larvae reflect the magnitude of up-regulation of the HSP90 gene in response to heat-shock. The demonstrated role of NO as a positive metamorphic regulator in H. momus suggests the existence of inter-specific adaptations of NO regulation in ascidian

Assessment of Dephosphorization During Vanadium Extraction Process in Converter

NASA Astrophysics Data System (ADS)

Chen, Lian; Diao, Jiang; Wang, Guang; Xie, Bing

2018-06-01

Dephosphorization during the vanadium extraction process in the converter was studied. The effects of the slag basicity and FeO content on the dephosphorization and the mineral phases in the phosphorus-containing vanadium slag are discussed. The results show that removal of phosphorus from the hot metal during the vanadium extraction process can be achieved by adding lime into the vanadium extraction converter. The highest dephosphorization rate was obtained at slag basicity of 1.93. The phosphorus distribution ratio increased with increasing FeO content up to 16-18% but decreased thereafter. Vanadium was present in the slag only as spinels rather than calcium vanadate. Phosphorus was still present in the form of calcium phosphate eutectic in calcium silicate. The present work proves that the vanadium extraction and dephosphorization processes are nonconflicting reactions.

Vanadium hydride deuterium-tritium generator

DOEpatents

Christensen, Leslie D.

1982-01-01

A pressure controlled vanadium hydride gas generator to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

Photocatalytic Activity of Vanadium-Substituted ETS-10

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

Nash,M.; Rykov, S.; Lobo, R.

2007-01-01

Various amounts of vanadium have been isomorphously substituted for titanium in ETS-10, creating samples with V/(V+Ti) ratios of 0.13, 0.33, 0.43, and 1.00 and characterized experimentally using Raman, near-edge X-ray absorption fine structure (NEXAFS), X-ray powder diffraction, N{sub 2} adsorption, scanning electron microscopy (SEM), UV/vis spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Raman spectra reveal a disordered chain structure that contains different V-O bonds along with the presence of a V-O-Ti peak. The UV/vis spectra of the vanadium samples have three new absorption features in the visible region at 450, 594, and 850 nm, suggesting both V{sup 4+}more » and V{sup 5+} are present in the samples. NEXAFS results confirm the presence of both V{sup 5+} and V{sup 4+} in the vanadium samples, with a fraction of V{sup 4+} within the range of 0.2-0.4. The addition of vanadium lowers the band gap energy of ETS-10 from 4.32 eV to a minimum of 3.58 eV for the 0.43ETVS-10 sample. Studies of the photocatalytic polymerization of ethylene show that the 594 nm transition has no photocatalytic activity. The visible transition around 450 nm in the vanadium-incorporated samples is photocatalytically active, and the lower-concentration vanadium samples have higher photocatalytic activity than that of ETS-10 and AM-6, the all-vanadium analogue of ETS-10.« less

VANADIUM CHEMISTRY ESSENTIALS FOR TREATMENT STUDIES

EPA Science Inventory

The importance of vanadium occurrence and treatment in drinking water has been elevated by its inclusion in the Contaminant Candidate List. Though it is still too early to know the nature of new regulatory requirements for vanadium, if indeed it becomes regulated, a substantial u...

Transformation and precipitation in vanadium treated steels

NASA Astrophysics Data System (ADS)

Vassiliou, Andreas D.

A series of carbon manganese steels containing varying amounts of carbon, vanadium and nitrogen was investigated in relation to the solubility of VC and VN in austenite, the grain coarsening characteristics of austenite, the tempering of martensite and other structures, the transformation during continuous cooling, the effect of vanadium addition and increasing nitrogen content on the thermo-mechanical processing of austenite, and the transformation of various morphologies of austenite to ferrite.The sites for preferential nucleation and growth of ferrite were identified and the effect of ferrite grain size inhomogeneity was investigated with a view to minimising it.The C/N ratio in the V(CN) precipitates was largely controlled by C/N ratio in the steel and it was also influenced by the austenitising treatment. As expected, the solubility of VN was less than that of VC.A systematic investigation of austenitising time and temperature on the grain coarsening characteristics was carried out showing the effects of vanadium, carbon and nitrogen. It was tentatively suggested that C-C and N-N clustering in the vanadium free steels controlled the grain growth whereas in the presence of vanadium, it was shown that VN and VC pinned the austenite grain boundaries and restricted grain growth. However coarsening or solution of VC and VN allowed the grain bondaries to migrate and grain coarsening occurred. The grain coarsening temperature was controlled predominantly by VN, whilst the VC dissolved frequently below the grain coarsening temperature.In the as quenched martensite, increasing nitrogen progressively increased the as quenched hardness, and the hardness also greatly increased with increasing carbon and vanadium added together. Examining the precipitation strengthening in tempered martensite showed that in the absence of vanadium, martensite softened progressively with increasing temperature and time. Vanadium additions increased the hardness level during low temperature

Dual mechanism controls asymmetric spindle position in ascidian germ cell precursors.

PubMed

Prodon, François; Chenevert, Janet; Hébras, Céline; Dumollard, Rémi; Faure, Emmanuel; Gonzalez-Garcia, Jose; Nishida, Hiroki; Sardet, Christian; McDougall, Alex

2010-06-01

Mitotic spindle orientation with respect to cortical polarity cues generates molecularly distinct daughter cells during asymmetric cell division (ACD). However, during ACD it remains unknown how the orientation of the mitotic spindle is regulated by cortical polarity cues until furrowing begins. In ascidians, the cortical centrosome-attracting body (CAB) generates three successive unequal cleavages and the asymmetric segregation of 40 localized postplasmic/PEM RNAs in germ cell precursors from the 8-64 cell stage. By combining fast 4D confocal fluorescence imaging with gene-silencing and classical blastomere isolation experiments, we show that spindle repositioning mechanisms are active from prometaphase until anaphase, when furrowing is initiated in B5.2 cells. We show that the vegetal-most spindle pole/centrosome is attracted towards the CAB during prometaphase, causing the spindle to position asymmetrically near the cortex. Next, during anaphase, the opposite spindle pole/centrosome is attracted towards the border with neighbouring B5.1 blastomeres, causing the spindle to rotate (10 degrees /minute) and migrate (3 microm/minute). Dynamic 4D fluorescence imaging of filamentous actin and plasma membrane shows that precise orientation of the cleavage furrow is determined by this second phase of rotational spindle displacement. Furthermore, in pairs of isolated B5.2 blastomeres, the second phase of rotational spindle displacement was lost. Finally, knockdown of PEM1, a protein localized in the CAB and required for unequal cleavage in B5.2 cells, completely randomizes spindle orientation. Together these data show that two separate mechanisms active during mitosis are responsible for spindle positioning, leading to precise orientation of the cleavage furrow during ACD in the cells that give rise to the germ lineage in ascidians.

Aqueous vanadium ion dynamics relevant to bioinorganic chemistry: A review.

PubMed

Kustin, Kenneth

2015-06-01

Aqueous solutions of the four highest vanadium oxidation states exhibit four diverse colors, which only hint at the diverse reactions that these ions can undergo. Cationic vanadium ions form complexes with ligands; anionic vanadium ions form complexes with ligands and self-react to form isopolyanions. All vanadium species undergo oxidation-reduction reactions. With a few exceptions, elucidation of the dynamics of these reactions awaited the development of fast reaction techniques before the kinetics of elementary ligation, condensation, reduction, and oxidation of the aqueous vanadium ions could be investigated. As the biological roles played by endogenous and therapeutic vanadium expand, it is appropriate to bring the results of the diverse kinetics studies under one umbrella. To achieve this goal this review presents a systematic examination of elementary aqueous vanadium ion dynamics. Copyright © 2014 Elsevier Inc. All rights reserved.

Vanadium hydride deuterium-tritium generator

DOEpatents

Christensen, L.D.

1980-03-13

A pressure controlled vanadium hydride gas generator was designed to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

Structural and silver/vanadium ratio effects on silver vanadium phosphorous oxide solution formation kinetics: impact on battery electrochemistry.

PubMed

Bock, David C; Takeuchi, Kenneth J; Marschilok, Amy C; Takeuchi, Esther S

2015-01-21

The detailed understanding of non-faradaic parasitic reactions which diminish battery calendar life is essential to the development of effective batteries for use in long life applications. The dissolution of cathode materials including manganese, cobalt and vanadium oxides in battery systems has been identified as a battery failure mechanism, yet detailed dissolution studies including kinetic analysis are absent from the literature. The results presented here provide a framework for the quantitative and kinetic analyses of the dissolution of cathode materials which will aid the broader community in more fully understanding this battery failure mechanism. In this study, the dissolution of silver vanadium oxide, representing the primary battery powering implantable cardioverter defibrillators (ICD), is compared with the dissolution of silver vanadium phosphorous oxide (Ag(w)VxPyOz) materials which were targeted as alternatives to minimize solubility. This study contains the first kinetic analyses of silver and vanadium solution formation from Ag0.48VOPO4·1.9H2O and Ag2VP2O8, in a non-aqueous battery electrolyte. The kinetic results are compared with those of Ag2VO2PO4 and Ag2V4O11 to probe the relationships among crystal structure, stoichiometry, and solubility. For vanadium, significant dissolution was observed for Ag2V4O11 as well as for the phosphate oxide Ag0.49VOPO4·1.9H2O, which may involve structural water or the existence of multiple vanadium oxidation states. Notably, the materials from the SVPO family with the lowest vanadium solubility are Ag2VO2PO4 and Ag2VP2O8. The low concentrations and solution rates coupled with their electrochemical performance make these materials interesting alternatives to Ag2V4O11 for the ICD application.

Vanadium-pumped titanium x-ray laser

DOEpatents

Nilsen, J.

1992-05-26

A resonantly photo-pumped x-ray laser is formed of a vanadium and titanium foil combination that is driven by two beams of intense line focused optical laser radiation. Ground state neon-like titanium ions are resonantly photo-pumped by line emission from fluorine-like vanadium ions. 4 figs.

Mineralogy and geochemistry of vanadium in the Colorado Plateau

USGS Publications Warehouse

Weeks, A.D.

1961-01-01

The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

Vanadium bioavailability and toxicity to soil microorganisms and plants.

PubMed

Larsson, Maja A; Baken, Stijn; Gustafsson, Jon Petter; Hadialhejazi, Golshid; Smolders, Erik

2013-10-01

Vanadium, V, is a redox-sensitive metal that in solution, under aerobic conditions, prevails as the oxyanion vanadate(V). There is little known regarding vanadium toxicity to soil biota, and the present study was set up to determine the toxicity of added vanadate to soil organisms and to investigate the relationship between toxicity and vanadium sorption in soils. Five soils with contrasting properties were spiked with 7 different doses (3.2-3200 mg V kg(-1)) of dissolved vanadate, and toxicity was measured with 2 microbial and 3 plant assays. The median effective concentration (EC50) thresholds of the microbial assays ranged from 28 mg added V kg(-1) to 690 mg added V kg(-1), and the EC50s in the plant assays ranged from 18 mg added V kg(-1) to 510 mg added V kg(-1). The lower thresholds were in the concentration range of the background vanadium in the untreated control soils (15-58 mg V kg(-1)). The vanadium toxicity to plants decreased with a stronger soil vanadium sorption strength. The EC50 values for plants expressed on a soil solution basis ranged from 0.8 mg V L(-1) to 15 mg V L(-1) and were less variable among soils than corresponding values based on total vanadium in soil. It is concluded that sorption decreases the toxicity of added vanadate and that soil solution vanadium is a more robust measure to determine critical vanadium concentrations across soils. © 2013 SETAC.

Effect of vanadium compounds on acid phosphatase activity.

PubMed

Vescina, C M; Sálice, V C; Cortizo, A M; Etcheverry, S B

1996-01-01

The direct effect of different vanadium compounds on acid phosphatase (ACP) activity was investigated. Vanadate and vanadyl but not pervanadate inhibited the wheat germ ACP activity. These vanadium derivatives did not alter the fibroblast Swiss 3T3 soluble fraction ACP activity. Using inhibitors of tyrosine phosphatases (PTPases), the wheat germ ACP was partially characterized as a PTPase. This study suggests that the inhibitory ability of different vanadium derivatives to modulate ACP activity seems to depend on the geometry around the vanadium atom more than on the oxidation state. Our results indicate a correlation between the PTPase activity and the sensitivity to vanadate and vanadyl cation.

77 FR 51825 - Ferrovanadium and Nitrided Vanadium From Russia

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... Nitrided Vanadium From Russia Determination On the basis of the record \\1\\ developed in the subject five... order on ferrovanadium and nitrided vanadium from Russia would not be likely to lead to continuation or... in USITC Publication 4345 (August 2012), entitled Ferrovanadium and Nitrided Vanadium from Russia...

Chloride supporting electrolytes for all-vanadium redox flow batteries.

PubMed

Kim, Soowhan; Vijayakumar, M; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Chen, Feng; Hu, Jianzhi; Li, Liyu; Yang, Zhenguo

2011-10-28

This paper examines vanadium chloride solutions as electrolytes for an all-vanadium redox flow battery. The chloride solutions were capable of dissolving more than 2.3 M vanadium at varied valence states and remained stable at 0-50 °C. The improved stability appeared due to the formation of a vanadium dinuclear [V(2)O(3)·4H(2)O](4+) or a dinuclear-chloro complex [V(2)O(3)Cl·3H(2)O](3+) in the solutions over a wide temperature range. The all-vanadium redox flow batteries with the chloride electrolytes demonstrated excellent reversibility and fairly high efficiencies. Only negligible, if any, gas evolution was observed. The improved energy capacity and good performance, along with the ease in heat management, would lead to substantial reduction in capital cost and life-cycle cost, making the vanadium chloride redox flow battery a promising candidate for stationary applications. This journal is © the Owner Societies 2011

Recycling of Ammonia Wastewater During Vanadium Extraction from Shale

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-03-01

In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4 + is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia wastewater leaching and crystallization during vanadium extraction from shale. The effects of the NH4 + concentration, temperature, time and liquid-to-solid ratio on the leaching efficiencies of vanadium, aluminum and potassium were investigated, and the results showed that 93.2% of vanadium, 86.3% of aluminum and 96.8% of potassium can be leached from sulfation-roasted shale. Subsequently, 80.6% of NH4 + was separated from the leaching solution via cooling crystallization. Vanadium was recovered via a combined method of solvent extraction, precipitation and calcination. Therefore, ammonia wastewater was successfully recycled during vanadium extraction from shale.

Vanadium pentoxide

Integrated Risk Information System (IRIS)

Vanadium pentoxide ; CASRN 1314 - 62 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

Anion-conductive membranes with ultralow vanadium permeability and excellent performance in vanadium flow batteries.

PubMed

Mai, Zhensheng; Zhang, Huamin; Zhang, Hongzhang; Xu, Wanxing; Wei, Wenping; Na, Hui; Li, Xianfeng

2013-02-01

Anion exchange membranes prepared from quaternized poly(tetramethyl diphenyl ether sulfone) (QAPES) were first investigated in the context of vanadium flow battery (VFB) applications. The membranes showed an impressive suppression effect on vanadium ions. The recorded vanadium permeability was 0.02×10(-7)-0.09×10(-7) cm(2) min(-1), which was two orders of magnitude lower than that of Nafion 115. The self-discharge duration of a VFB single cell with a QAPES membrane is four times longer than that of Nafion 115. The morphological difference in hydrophilic domains between QAPES and Nafion was confirmed by TEM. After soaking the membranes in VO(2)(+) solution, adsorbed vanadium ions can barely be found in QAPES, whereas the hydrophilic domains of Nafion were stained. In the ex situ chemical stability test, QAPES showed a high tolerance to VO(2)(+) and remained intact after immersion in VO(2)(+) solution for over 250 h. The performance of a VFB single cell assembled with QAPES membranes is equal to or even better than that of Nafion 115 and remains stable in a long-term cycle test. These results indicate that QAPES membranes can be an ideal option in the fabrication of high-performance VFBs with low electric capacity loss. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparative erythropoietic effects of three vanadium compounds.

PubMed

Hogan, G R

2000-07-10

The biotoxic effects of vanadium are variable depending upon a number of factors including the oxidation state of the test compound. This study reports the effects of three vanadium compounds on peripheral erythrocytes. On day 0 female ICR mice received a single injection of vanadium chloride (V-III), vanadyl sulfate (V-IV), or sodium orthovandate (V-V). At scheduled intervals post-injection, the number of circulating erythrocytes [red blood cells per millimeter cubed (RBC/mm3)], reticulocyte percentages, and radioiron uptake percentages were determined and compared to mice receiving saline only. Data show that all three test substances promoted a significant lowering of RBC/mm3 beginning on day 1 for V-IV and V-V and on day 2 for V-III through day 4. The reticulocyte percentages increase followed the same time course as that of the peripheral RBC decrease. Peak reticulocytosis was noted on days 2 and 4 for all three vanadium-treated groups; for V-IV and V-V the increase continued to day 6. Radioiron data showed an erythropoietic stimulation by a significant increase in uptake percentages on days 4-6 after vanadium injections compared to saline-treated controls.

Vanadium exposure-induced striatal learning and memory alterations in rats.

PubMed

Sun, Liping; Wang, Keyue; Li, Yan; Fan, Qiyuan; Zheng, Wei; Li, Hong

2017-09-01

Occupational and environmental exposure to vanadium has been associated with toxicities in reproductive, respiratory, and cardiovascular systems. The knowledge on whether and how vanadium exposure caused neurobehavioral changes remains incomplete. This study was designed to investigate the changes in learning and memory following drinking water exposure to vanadium, and to conduct the preliminary study on underlying mechanisms. Male Sprague-Dawley rats were exposed to vanadium dissolved in drinking water at the concentration of 0.0, 0.5, 1.0 and 2.0g/L, as the control, low-, medium-, and high- dose groups, respectively, for 12 weeks. The results by the Morris water maze test showed that the time for the testing animal to find the platform in the high exposed group was increased by 82.9% and 49.7%, as compared to animals in control and low-dose groups (p<0.05). There were significantly fewer rats in the medium- and high- dose groups than in the control group who were capable of crossing the platform (p<0.05). Quantitation of vanadium by atomic absorption spectrophotometry revealed a significant dose-dependent accumulation of vanadium in striatum (r=0.931, p<0.01). Histopathological examination further demonstrated a degenerative damage in vanadium-exposed striatum. Interestingly, with the increase of the dose of vanadium, the contents of neurotransmitter ACh, 5-HT and GABA in the striatum increased; however, the levels of Syn1 was significantly reduced in the exposed groups compared with controls (p<0.05). These data suggest that vanadium exposure apparently reduces the animals' learning ability. This could be due partly to vanadium's accumulation in striatum and the ensuing toxicity to striatal structure and synaptic plasticity. Further research is warranted for mechanistic understanding of vanadium-induced neurotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

IRIS Toxicological Review of Vanadium Pentoxide ...

EPA Pesticide Factsheets

On September 30, 2011, the draft Toxicological Review of Vanadium Pentoxide and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices before public release. In the new IRIS process (May 2009), introduced by the EPA Administrator, all written comments on IRIS assessments submitted by other federal agencies and White House Offices will be made publicly available. Accordingly, interagency comments and the interagency science consultation draft of the IRIS Toxicological Review of Vanadium Pentoxide and the charge to external peer reviewers are posted on this site. EPA is reassessing its IRIS toxicological review of vanadium pentoxide (CASRN 1314-62-1). This vanadium pentoxide reassessment consists of an oral reference dose (RfD), an inhalation reference concentration (RfC), an inhalation unit risk (IUR) and a cancer weight of evidence descriptor. This is the first assessment developing an RfC or IUR for this compound. This assessment is intended to provide human health data to support agency regulatory decisions.

Plasma enhanced chemical vapor deposition (PECVD) method of forming vanadium oxide films and vanadium oxide thin-films prepared thereby

DOEpatents

Zhang, Ji-Guang; Tracy, C. Edwin; Benson, David K.; Turner, John A.; Liu, Ping

2000-01-01

A method is disclosed of forming a vanadium oxide film on a substrate utilizing plasma enhanced chemical vapor deposition. The method includes positioning a substrate within a plasma reaction chamber and then forming a precursor gas comprised of a vanadium-containing chloride gas in an inert carrier gas. This precursor gas is then mixed with selected amounts of hydrogen and oxygen and directed into the reaction chamber. The amounts of precursor gas, oxygen and hydrogen are selected to optimize the final properties of the vanadium oxide film An rf plasma is generated within the reaction chamber to chemically react the precursor gas with the hydrogen and the oxygen to cause deposition of a vanadium oxide film on the substrate while the chamber deposition pressure is maintained at about one torr or less. Finally, the byproduct gases are removed from the plasma reaction chamber.

Vanadium-pumped titanium x-ray laser

DOEpatents

Nilsen, Joseph

1992-01-01

A resonantly photo-pumped x-ray laser (10) is formed of a vanadium (12) and titanium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state neon-like titanium ions (34) are resonantly photo-pumped by line emission from fluorine-like vanadium ions (32).

Effect of Vanadium and Tea Polyphenols on Intestinal Morphology, Microflora and Short-Chain Fatty Acid Profile of Laying Hens.

PubMed

Yuan, Z H; Wang, J P; Zhang, K Y; Ding, X M; Bai, S P; Zeng, Q F; Xuan, Y; Su, Z W

2016-12-01

Vanadium (V) is a trace element which can induce dysfunction of gastro-intestine and egg quality deterioration of laying hens. This study was conducted to determine the effect of tea polyphenols (TP) on intestinal morphology, microflora, and short-chain fatty acid (SCFA) profile of laying hens fed vanadium containing diets. A total of 120 Lohman laying hens (67-week-old) were randomly divided into 4 groups with 6 replicates and 5 birds each for a 35-day feeding trial. The dietary treatments were as follows: (1) control (CON), fed a basal diet; (2) vanadium treatment (V10), CON +10 mg V/kg; (3) TP treatment 1 (TP1): V10 + 600 mg TP/kg; (4) TP treatment 2 (TP2): V10 + 1000 mg TP/kg. Fed 10 mg V/kg diets to laying hens did not affect the cecum flora diversity index (H), degree of homogeneity (EH), and richness (S), but hens fed TP2 diet decreased the H, EH, and S (P < 0.05). The cecum butyrate acid concentration was lower in V10 treatment and higher in TP2 treatment (P < 0.05). Addition of 10 mg/kg V resulted in an increased (P < 0.01) duodenal cell apoptosis rate, and 1000 mg/kg TP supplementation overcame (P < 0.01) this reduction effect induced by vanadium. The results indicated that supplementation of 10 mg/kg vanadium increased duodenal cell apoptosis and reduced cecum butyrate acid content. Addition of 1000 mg/kg TP increased the SCFA production to affect cecum flora ecology and protected the duodenal cell from excess apoptosis caused by vanadium.

Kinetic model of whole-body vanadium metabolism: studies in sheep

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

Patterson, B.W.; Hansard, S.L. II; Ammerman, C.B.

1986-08-01

A compartmental model for vanadium metabolism in sheep has been proposed. The model is consistent with data obtained from sheep fed a control diet (2.6 ppm vanadium) containing 0 or 200 ppm supplemental vanadium. Sheep were administered UYV dioxovanadium either orally or intravenously. Blood feces, and urine radioactivity were monitored for 6 days postdosing. Several new insights regarding vanadium metabolism are suggested and tested against the data using the model. Some of these include 1) significant absorption of UYV occurs from the upper gastrointestinal tract; 2) an in vivo process is necessary in order for UYV dioxovanadium to be convertedmore » into a more biologically reactive species; 3) at steady state the upper and lower gastrointestinal tracts contain at least 10- and 100-fold more mass of vanadium, respectively, than does blood. No statistically significant differences in transport rate constants were found between animals receiving 0 and 200 ppm supplemental dietary vanadium. The availability of a model will enable the refinement of future studies regarding vanadium metabolism in the ruminant.« less

Vanadium exposure-induced striatal learning and memory alterations in rats

PubMed Central

Sun, Liping; Wang, Keyue; Li, Yan; Fan, Qiyuan; Zheng, Wei; Li, Hong

2017-01-01

Occupational and environmental exposure to vanadium has been associated with toxicities in reproductive, respiratory, and cardiovascular systems. The knowledge on whether and how vanadium exposure caused neurobehavioral changes remains incomplete. This study was designed to investigate the changes in learning and memory following drinking water exposure to vanadium, and to conduct the preliminary study on underlying mechanisms. Male Sprague-Dawley rats were exposed to vanadium dissolved in drinking water at the concentration of 0.0, 0.5, 1.0 and 2.0 g/L, as the control, low-, medium-, and high- dose groups, respectively, for 12 weeks. The results by the Morris water maze test showed that the time for the testing animal to find the platform in the high exposed group was increased by 82.9% and 49.7%, as compared to animals in control and low-dose groups (p <0.05). There were significantly fewer rats in the medium- and high- dose groups than in the control group who were capable of crossing the platform (p <0.05). Quantitation of vanadium by atomic absorption spectrophotometry revealed a significant dose-dependent accumulation of vanadium in striatum (r = 0.931, p <0.01). Histopathological examination further demonstrated a degenerative damage in vanadium-exposed striatum. Interestingly, with the increase of the dose of vanadium, the contents of neurotransmitter ACh, 5-HT and GABA in the striatum increased; however, the levels of Syn1 was significantly reduced in the exposed groups compared with controls (p <0.05). These data suggest that vanadium exposure apparently reduces the animals’ learning ability. This could be due partly to vanadium’s accumulation in striatum and the ensuing toxicity to striatal structure and synaptic plasticity. Further research is warranted for mechanistic understanding of vanadium-induced neurotoxicity. PMID:28625925

Nanocrystalline ordered vanadium carbide: Superlattice and nanostructure

NASA Astrophysics Data System (ADS)

Kurlov, A. S.; Gusev, A. I.; Gerasimov, E. Yu.; Bobrikov, I. A.; Balagurov, A. M.; Rempel, A. A.

2016-02-01

The crystal structure, micro- and nanostructure of coarse- and nanocrystalline powders of ordered vanadium carbide V8C7 have been examined by X-ray and neutron diffraction and electron microscopy methods. The synthesized coarse-crystalline powder of ordered vanadium carbide has flower-like morphology. It was established that the real ordered phase has the composition V8C7-δ (δ ≅ 0.03) deviating from perfect stoichiometric composition V8C7. The vanadium atoms forming the octahedral environment □V6 of vacant sites in V8C7-δ are displaced towards the vacancy □. The presence of carbon onion-like structures was found in the vanadium carbide powders with a small content of free (uncombined) carbon. The nanopowders of V8C7-δ carbide with average particle size of 20-30 nm produced by high-energy milling of coarse-crystalline powder retain the crystal structure of the initial powder, but differ in the lattice deformation distortion anisotropy.

Catalytic determination of vanadium in water

USGS Publications Warehouse

Fishman, M. J.; Skougstad, M.W.

1964-01-01

A rapid, accurate, and sensitive spectrophotometric method for the quantitative determination of trace amounts of vanadium in water is based on the catalytic effect of vanadium on the rate of oxidation of gallic acid by persulfate in acid solution. Under given conditions of concentrations of reactants, temperature, and reaction time, the extent of oxidation of gallic acid is proportional to the concentration of vanadium present. Vanadium is determined by measuring the absorbance of the sample at 415 m?? and comparison with standard solutions treated in an identical manner. Concentrations in the range of from 0.1 to 8.0 ??g. per liter may be determined with a standard deviation of 0.2 or less. By reducing the reaction time, the method may be extended to cover the range from 1 to 100 ??g. with a standard deviation of 0.8 or less. Several substances interfere, including chloride above 100 p.p.m., and bromide and iodide in much lower concentrations. Interference from the halides is eliminated or minimized by the addition of mercuric nitrate solution. Most other substances do not interfere at the concentration levels at which they commonly occur in natural waters.

DNA damage induction in human cells exposed to vanadium oxides in vitro.

PubMed

Rodríguez-Mercado, Juan J; Mateos-Nava, Rodrigo A; Altamirano-Lozano, Mario A

2011-12-01

Vanadium and vanadium salts cause genotoxicity and elicit variable biological effects depending on several factors. In the present study, we analyzed and compared the DNA damage and repair processes induced by vanadium in three oxidation states. We used human blood leukocytes in vitro and in a single cell gel electrophoresis assay at two pH values. We observed that vanadium(III) trioxide and vanadium(V) pentoxide produced DNA single-strand breaks at all of the concentrations (1, 2, 4, or 8 μg/ml) and treatment times (2, 4, or 6 h) tested. Vanadium(IV) tetraoxide treatment significantly increased DNA damage at all concentrations for 4 or 6 h of treatment but not for 2 h of treatment. The DNA repair kinetics indicated that most of the cells exposed to vanadium III and V for 4 h recovered within the repair incubation time of 90 min; however, those exposed to vanadium(IV) repaired their DNA within 120 min. The data at pH 9 indicated that vanadium(IV) tetraoxide induced DNA double-strand breaks. Our results show that the genotoxic effect of vanadium can be produced by any of its three oxidation states. However, vanadium(IV) induces double-strand breaks, and it is known that these lesions are linked with forming structural chromosomal aberrations. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electronic structure of lead telluride-based alloys, doped with vanadium

NASA Astrophysics Data System (ADS)

Skipetrov, E. P.; Golovanov, A. N.; Slynko, E. I.; Slynko, V. E.

2013-01-01

The crystal structure, composition, galvanomagnetic properties in low magnetic fields (4.2 K ≤ T ≤ 300 K, B ≤ 0.07 T), and the Shubnikov-de Haas effect (T = 4.2 K, B ≤ 7 T) are studied in Pb1-x-ySnxVyTe (x = 0, 0.05-0.18) alloys synthesized by the Bridgman technique with variable vanadium impurity concentrations. It is shown that increasing the vanadium content leads to the formation of regions enriched in vanadium and of microscopic inclusions of compounds with compositions close to V3Te4. In Pb1-yVyTe stabilization of the Fermi level by a deep vanadium level, an insulator-metal transition, and a rise in the free electron concentration are observed as the vanadium content is increased. The variation in the free charge carrier concentration with increasing vanadium concentration in Pb1-yVyTe and Pb1-x-ySnxVyTe (x = 0.05-0.18) alloys is compared. Possible models for rearrangement of the electronic structure in Pb1-x-ySnxVyTe alloys with vanadium doping are discussed.

Essentiality and toxicity of vanadium supplements in health and pathology.

PubMed

Gruzewska, K; Michno, A; Pawelczyk, T; Bielarczyk, H

2014-10-01

The biological properties of vanadium complexes have become an object of interest due to their therapeutic potential in several diseases. However, the mechanisms of action of vanadium salts are still poorly understood. Vanadium complexes are cofactors for several enzymes and also exhibit insulin-mimetic properties. Thus, they are involved in the regulation of glucose metabolism, including in patients with diabetes. In addition, vanadium salts may also normalize blood pressure and play a key role in the metabolism of the thyroid and of iron as well as in the regulation of total cholesterol, cholesterol HDL and triglyceride (TG) levels in blood. Moreover, in cases of hypoxia, vanadium compounds may improve cardiomyocytes function. They may also exhibit both carcinogenic and anti-cancer properties. These include dose- and exposure-time-dependent induction and inhibition of the proliferation and survival of cancer cells. On the other hand, the balance between vanadium's therapeutic properties and its side effects has not yet been determined. Therefore, any studies on the potential use of vanadium compounds as supplements to support the treatment of a number of diseases must be strictly monitored for adverse effects.

Molecular geometry of vanadium dichloride and vanadium trichloride: a gas-phase electron diffraction and computational study.

PubMed

Varga, Zoltán; Vest, Brian; Schwerdtfeger, Peter; Hargittai, Magdolna

2010-03-15

The molecular geometries of VCl2 and VCl3 have been determined by computations and gas-phase electron diffraction (ED). The ED study is a reinvestigation of the previously published analysis for VCl2. The structure of the vanadium dichloride dimer has also been calculated. According to our joint ED and computational study, the evaporation of a solid sample of VCl2 resulted in about 66% vanadium trichloride and 34% vanadium dichloride in the vapor. Vanadium dichloride is unambiguously linear in its 4Sigma(g)+ ground electronic state. For VCl3, all computations yielded a Jahn-Teller-distorted ground-state structure of C(2v) symmetry. However, it lies merely less than 3 kJ/mol lower than the 3E'' state (D(3h) symmetry). Due to the dynamic nature of the Jahn-Teller effect in this case, rigorous distinction cannot be made between the planar models of either D(3h) symmetry or C(2v) symmetry for the equilibrium structure of VCl3. Furthermore, the presence of several low-lying excited electronic states of VCl3 is expected in the high-temperature vapor. To our knowledge, this is the first experimental and computational study of the VCl3 molecule.

A multigene locus containing the Manx and bobcat genes is required for development of chordate features in the ascidian tadpole larva.

PubMed

Swalla, B J; Just, M A; Pederson, E L; Jeffery, W R

1999-04-01

The Manx gene is required for the development of the tail and other chordate features in the ascidian tadpole larva. To determine the structure of the Manx gene, we isolated and sequenced genomic clones from the tailed ascidian Molgula oculata. The Manx gene contains 9 exons and encodes both major and minor Manx mRNAs, which differ in the length of their 5' untranslated regions. The coding region of the single-copy bobcat gene, which encodes a DEAD-box RNA helicase, is embedded within the first Manx intron. The organization of the bobcat and Manx transcription units was determined by comparing genomic and cDNA clones. The Manx-bobcat gene locus has an unusual organization in which a non-coding first exon is alternatively spliced at the 5' end of two different mRNAs. The bobcat and Manx genes are expressed coordinately during oogenesis and embryogenesis, but not during spermatogenesis, in which bobcat mRNA accumulates independently of Manx mRNA. Similar to Manx, zygotic bobcat transcripts accumulate in the embryonic primordia responsible for generating chordate features, including the dorsal neural tube and notochord, are downregulated during embryogenesis in the tailless species Molgula occulta and are upregulated in M. occulta X M. oculata hybrids, which restore these chordate features. Antisense experiments indicate that zygotic bobcat expression is required for development of the same suite of chordate features as Manx. The results show that the Manx-bobcat gene complex has a role in the development of chordate features in ascidian tadpole larvae.

Effect of hydrogen on fatigue crack propagation in vanadium

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

Chung, D.W.; Stoloff, N.S.

The influence of hydrogen on fatigue crack propagation in unalloyed vanadium and several hydrogen-charged vanadium alloys has been investigated. The Paris--Erdogan equation, da/dN = C(..delta..K)/sup m/, was approximately obeyed for all alloys. Crack growth rates were lowest in vanadium and dilute vanadium-hydrogen alloys, and were not very sensitive to volume fraction of hydrides in more concentrated alloys. The crack growth exponent, m, is inversely proportional to the cyclic strain hardening rate, n', and the rate constant C is inversely proportional to the square of the ultimate tensile stress, sigma/sub UTS/: metallographic examination showed hydride reorientation and growth in the originallymore » hydrided alloys. No stress-induced hydrides were observed in V-H solid-solution alloys. Fractures in hydrided materials exhibited cleavage-like features, while striations were noted in unalloyed vanadium and dilute solid-solution alloys.« less

Effect of hydrogen on fatigue crack propagation in vanadium

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

Chung, D.W.; Stoloff, N.S.

The influence of hydrogen on fatigue crack propagation in unalloyed vanadium and several hydrogen-charged vanadium alloys has been investigated. The Paris--Erdogan equation, da/dN = C(..delta..K)/sup m/, was approximately obeyed for all alloys. Crack growth rates were lowest in vanadium and dilute vanadium--hydrogen alloys, and were not very sensitive to volume fraction of hydrides in more concentrated alloys. The crack growth exponent, m, is inversely proportional to the cyclic strain hardening rate, n', and the rate constant C is inversely proportional to the square of the ultimate tensile stress, sigma/sub UTS/: metallographic examination showed hydride reorientation and growth in the originallymore » hydrided alloys. No stress-induced hydrides were observed in V--H solid-solution alloys. Fractures in hydrided materials exhibited cleavage-like features, while striations were noted in unalloyed vanadium and dilute solid-solution alloys.« less

Spectrophotometric determination of vanadium in rutile and in mafic igneous rocks

USGS Publications Warehouse

Marinenko, John; Mei, Leung

1974-01-01

Minor and major levels of vanadium in rutile are separated from titanium and iron by sample fusion with sodium carbonate followed by water leach and filtration. The filtrate is then acidified with hydrochloric acid. Silicates are decomposed with a mixture of hydrofluoric and hydrochloric acids, and iron is separated by extraction of its chloride with diethyl ether. Sample vanadium in hydrochloric acid is then quantitatively reduced to vanadium(IV) with sulfurous acid. The remaining sulfur dioxide is expelled by heating. Vanadium (IV) then is reacted with excess of iron(III) at reduced acidity (pH 5) in the presence of 1,10-phenanthroline to yield the orange-red iron(II) 1,10-phenanthroline complex. Iron(II) generated by vanadium(IV) is a measure of total vanadium in the sample. The proposed method is free from elemental interferences because the color development cannot take place without the two redox reactions described above, and these are, under the outlined experimental conditions, quantitative only for vanadium.

Geochemistry of vanadium in an epigenetic, sandstone-hosted vanadium- uranium deposit, Henry Basin, Utah

USGS Publications Warehouse

Wanty, R.B.; Goldhaber, M.B.; Northrop, H.R.

1990-01-01

The epigenetic Tony M vanadium-uranium orebody in south-central Utah is hosted in fluvial sandstones of the Morrison Formation (Upper Jurassic). Measurements of the relative amounts of V+3 and V +4 in ore minerals show that V+3 is more abundant. Thermodynamic calculations show that vanadium was more likely transported to the site of mineralization as V+4. The ore formed as V+4 was reduced by hydrogen sulfide, followed by hydrolysis and precipitation of V+3 in oxide minerals or chlorite. Uranium was transported as uranyl ion (U+6), or some complex thereof, and reduced by hydrogen sulfide, forming coffinite. Detrital organic matter in the rocks served as the carbon source for sulfate-reducing bacteria. Vanadium most likely was derived from the dissolution of iron-titanium oxides. Uranium probably was derived from the overlying Brushy Basin Member of the Morrison Formation. Previous studies have shown that the ore formed at the density-stratified interface between a basinal brine and dilute meteoric water. The mineralization processes described above occurred within the mixing zone between these two fluids. -from Authors

NREL, American Vanadium Demonstrate First-of-Its-Kind Battery Management

Science.gov Websites

System | Energy Systems Integration Facility | NREL American Vanadium NREL, American Vanadium Demonstrate First-of-Its-Kind Battery Management System NREL researchers are collaborating with American Vanadium, an integrated energy storage company, to evaluate and demonstrate the first North American

Recent progress on gas tungsten arc welding of vanadium alloys

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

King, J.F.; Grossbeck, M.L.; Goodwin, G.M.

1997-04-01

This is a progress report on a continuing research project to acquire a fundamental understanding of the metallurgical processes in the welding of vanadium alloys. It also has the goal of developing techniques for welding structural vanadium alloys. The alloy V-4Cr-4Ti is used as a representative alloy of the group; it is also the prime candidate vanadium alloy for the U.S. Fusion Program at the present time. However, other alloys of this class were used in the research as necessary. The present work focuses on recent findings of hydrogen embrittlement found in vanadium alloy welds. It was concluded that themore » atmosphere in the inert gas glove box was insufficient for welding 6mm thick vanadium alloy plates.« less

Modified lithium vanadium oxide electrode materials products and methods

DOEpatents

Thackeray, Michael M.; Kahaian, Arthur J.; Visser, Donald R.; Dees, Dennis W.; Benedek, Roy

1999-12-21

A method of improving certain vanadium oxide formulations is presented. The method concerns fluorine doping formulations having a nominal formula of LiV.sub.3 O.sub.8. Preferred average formulations are provided wherein the average oxidation state of the vanadium is at least 4.6. Herein preferred fluorine doped vanadium oxide materials, electrodes using such materials, and batteries including at least one electrode therein comprising such materials are provided.

Computational studies of small neutral vanadium oxide clusters and their reactions with sulfur dioxide

NASA Astrophysics Data System (ADS)

Jakubikova, Elena; He, Sheng-Gui; Xie, Yan; Matsuda, Yoshiyuki; Bernstein, Elliot

2007-03-01

Vanadium oxide is a catalytic system that plays an important role in the conversion of SO2 to SO3. Density functional theory at the BPW91/LANL2DZ level is employed to obtain structures of VOy (y=1,,5), V2Oy (y=2,,7), V3Oy (y=4,,9), V4Oy (y=7,,12) and their complexes with SO2. BPW91/LANL2DZ is insufficient to describe properly relative V-O and S-O bond strengths of vanadium and sulfur oxides. Calibration of theoretical results with experimental data is necessary to compute enthalpies of reactions between VxOy and SO2. Theoretical results indicate SO2 to SO conversion occurs for oxygen-deficient clusters and SO2 to SO3 conversion occurs for oxygen-rich clusters. Subsequent experimental studies confirm the presence of SO in the molecular beam as well as the presence of VxOy complexes with SO2. Some possible mechanisms for SO3 formation and catalyst regeneration for solids are also suggested.

ANISEED 2017: extending the integrated ascidian database to the exploration and evolutionary comparison of genome-scale datasets

PubMed Central

Brozovic, Matija; Dantec, Christelle; Dardaillon, Justine; Dauga, Delphine; Faure, Emmanuel; Gineste, Mathieu; Louis, Alexandra; Naville, Magali; Nitta, Kazuhiro R; Piette, Jacques; Reeves, Wendy; Scornavacca, Céline; Simion, Paul; Vincentelli, Renaud; Bellec, Maelle; Aicha, Sameh Ben; Fagotto, Marie; Guéroult-Bellone, Marion; Haeussler, Maximilian; Jacox, Edwin; Lowe, Elijah K; Mendez, Mickael; Roberge, Alexis; Stolfi, Alberto; Yokomori, Rui; Cambillau, Christian; Christiaen, Lionel; Delsuc, Frédéric; Douzery, Emmanuel; Dumollard, Rémi; Kusakabe, Takehiro; Nakai, Kenta; Nishida, Hiroki; Satou, Yutaka; Swalla, Billie; Veeman, Michael; Volff, Jean-Nicolas

2018-01-01

Abstract ANISEED (www.aniseed.cnrs.fr) is the main model organism database for tunicates, the sister-group of vertebrates. This release gives access to annotated genomes, gene expression patterns, and anatomical descriptions for nine ascidian species. It provides increased integration with external molecular and taxonomy databases, better support for epigenomics datasets, in particular RNA-seq, ChIP-seq and SELEX-seq, and features novel interactive interfaces for existing and novel datatypes. In particular, the cross-species navigation and comparison is enhanced through a novel taxonomy section describing each represented species and through the implementation of interactive phylogenetic gene trees for 60% of tunicate genes. The gene expression section displays the results of RNA-seq experiments for the three major model species of solitary ascidians. Gene expression is controlled by the binding of transcription factors to cis-regulatory sequences. A high-resolution description of the DNA-binding specificity for 131 Ciona robusta (formerly C. intestinalis type A) transcription factors by SELEX-seq is provided and used to map candidate binding sites across the Ciona robusta and Phallusia mammillata genomes. Finally, use of a WashU Epigenome browser enhances genome navigation, while a Genomicus server was set up to explore microsynteny relationships within tunicates and with vertebrates, Amphioxus, echinoderms and hemichordates. PMID:29149270

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the vanadium ore...

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the vanadium ore...

Positron lifetime in vanadium oxide bronzes

NASA Astrophysics Data System (ADS)

Dryzek, J.; Dryzek, E.

2003-09-01

The positron lifetime (PL) and Doppler broadening (DB) of annihilation line measurements have been performed in vanadium oxide bronzes MxV2O5. The dependence of these annihilation characteristics on the kind and concentration of the metal M donor has been observed. In the PL spectrum only one lifetime component has been detected in all studied bronzes. The results indicate the positron localization in the structural tunnels present in the crystalline lattice of the vanadium oxide bronzes. (

Quantitation and detection of vanadium in biologic and pollution materials

NASA Technical Reports Server (NTRS)

Gordon, W. A.

1974-01-01

A review is presented of special considerations and methodology for determining vanadium in biological and air pollution materials. In addition to descriptions of specific analysis procedures, general sections are included on quantitation of analysis procedures, sample preparation, blanks, and methods of detection of vanadium. Most of the information presented is applicable to the determination of other trace elements in addition to vanadium.

Origin and Dispersal History of Two Colonial Ascidian Clades in the Botryllus schlosseri Species Complex.

PubMed

Nydam, Marie L; Giesbrecht, Kirsten B; Stephenson, Emily E

2017-01-01

Human-induced global warming and species introductions are rapidly altering the composition and functioning of Earth's marine ecosystems. Ascidians (Phylum Chordata, Subphylum Tunicata, Class Ascidiacea) are likely to play an increasingly greater role in marine communities. The colonial ascidian B. schlosseri is a cryptic species complex comprising five genetically divergent clades (A-E). Clade A is a global species, and Clade E has so far been identified in European waters only. Using the largest mitochondrial cytochrome oxidase I datasets yet assembled, we determine the origin and dispersal history of these species. Nucleotide diversity and Approximate Bayesian Computation analyses support a Pacific origin for Clade A, with two likely dispersal scenarios that both show the northwestern Atlantic populations establishing early in the history of the species. Both Discrete Phylogeographic Analysis and Approximate Bayesian Computation support an origin of Clade E on the French side of the English Channel. An unsampled lineage evolved from the French lineage, which reflects the conclusion from the median joining network that not all Clade E lineages have been sampled. This unsampled lineage gave rise to the haplotypes on the English side of the English Channel, which were the ancestors to the Mediterranean and Bay of Biscay populations. Clade E has a wider geographic range than previously thought, and shows evidence of recent range expansion. Both Clade A and Clade E should be considered widespread species: Clade A globally and Clade E within Europe.

Low-temperature direct synthesis of mesoporous vanadium nitrides for electrochemical capacitors

NASA Astrophysics Data System (ADS)

Lee, Hae-Min; Jeong, Gyoung Hwa; Kim, Sang-Wook; Kim, Chang-Koo

2017-04-01

Mesoporous vanadium nitrides are directly synthesized by a one-step chemical precipitation method at a low temperature (70 °C). Structural and morphological analyses reveal that vanadium nitride consist of long and slender nanowhiskers, and mesopores with diameters of 2-5 nm. Compositional analysis confirms the presence of vanadium in the VN structure, along with oxidized vanadium. The cyclic voltammetry and charge-discharge tests indicate that the obtained material stores charges via a combination of electric double-layer capacitance and pseudocapacitance mechanisms. The vanadium nitride electrode exhibits a specific capacitance of 598 F/g at a current density of 4 A/g. After 5000 charge-discharge cycles, the electrode has an equivalent series resistance of 1.42 Ω and retains 83% of its initial specific capacitance. This direct low-temperature synthesis of mesoporous vanadium nitrides is a simple and promising method to achieve high specific capacitance and low equivalent series resistance for electrochemical capacitor applications.

Nanostructured Electrocatalysts for All-Vanadium Redox Flow Batteries.

PubMed

Park, Minjoon; Ryu, Jaechan; Cho, Jaephil

2015-10-01

Vanadium redox reactions have been considered as a key factor affecting the energy efficiency of the all-vanadium redox flow batteries (VRFBs). This redox reaction determines the reaction kinetics of whole cells. However, poor kinetic reversibility and catalytic activity towards the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples on the commonly used carbon substrate limit broader applications of VRFBs. Consequently, modified carbon substrates have been extensively investigated to improve vanadium redox reactions. In this Focus Review, recent progress on metal- and carbon-based nanomaterials as an electrocatalyst for VRFBs is discussed in detail, without the intention to provide a comprehensive review on the whole components of the system. Instead, the focus is mainly placed on the redox chemistry of vanadium ions at a surface of various metals, different dimensional carbons, nitrogen-doped carbon nanostructures, and metal-carbon composites. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Kinetics and Equilibrium Study of Vanadium Dissolution from Vanadium Oxides and Phosphates in Battery Electrolytes: Possible Impacts on ICD Battery Performance.

PubMed

Bock, David C; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

2013-06-01

Silver vanadium oxide (Ag 2 V 4 O 11 , SVO) has enjoyed widespread commercial success over the past 30 years as a cathode material for implantable cardiac defibrillator (ICD) batteries. Recently, silver vanadium phosphorous oxide (Ag 2 VO 2 PO 4 , SVPO) has been studied as possibly combining the desirable thermal stability aspects of LiFePO 4 with the electrical conductivity of SVO. Further, due to the noted insoluble nature of most phosphate salts, a lower material solubility of SVPO relative to SVO is anticipated. Thus, the first vanadium dissolution studies of SVPO in battery electrolyte solutions are described herein. The equilibrium solubility of SVPO was ~5 times less than SVO, with a rate constant of dissolution ~3.5 times less than that of SVO. The vanadium dissolution in SVO and SVPO can be adequately described with a diffusion layer model, as supported by the Noyes-Whitney equation. Cells prepared with vanadium-treated anodes displayed higher AC impedance and DC resistance relative to control anodes. These data support the premise that SVPO cells are likely to exhibit reduced cathode solubility and thus less affected by increased cell resistance due to cathode solubility compared to SVO based cells.

Tackling capacity fading in vanadium flow batteries with amphoteric membranes

NASA Astrophysics Data System (ADS)

Oldenburg, Fabio J.; Schmidt, Thomas J.; Gubler, Lorenz

2017-11-01

Capacity fading and poor electrolyte utilization caused by electrolyte imbalance effects are major drawbacks for the commercialization of vanadium flow batteries (VFB). The influence of membrane type (cationic, anionic, amphoteric) on these effects is studied by determining the excess and net flux of each vanadium ion in an operating VFB assembled with a cation exchange membrane (CEM), Nafion® NR212, an anion exchange membrane (AEM), Fumatech FAP-450, and an amphoteric ion exchange membrane (AIEM) synthesized in-house. It is shown that the net vanadium flux, accompanied by water transport, is directed towards the positive side for the CEM and towards the negative side for the AEM. The content of cation and anion exchange groups in the AIEM is adjusted via radiation grafting to balance the vanadium flux between the two electrolyte sides. With the AIEM the net vanadium flux is significantly reduced and capacity fading due to electrolyte imbalances can be largely eliminated. The membrane's influence on electrolyte imbalance effects is characterized and quantified in one single charge-discharge cycle by analyzing the content of the four different vanadium species in the two electrolytes. The experimental data recorded herewith conclusively explains the electrolyte composition after 80 cycles.

Antimalarial β-carbolines from the New Zealand ascidian Pseudodistoma opacum.

PubMed

Chan, Susanna T S; Pearce, A Norrie; Page, Michael J; Kaiser, Marcel; Copp, Brent R

2011-09-23

One tetrahydro-β-carboline, (-)-7-bromohomotrypargine (1), and three alkylguanidine-substituted β-carbolines, opacalines A, B, and C (2-4), have been isolated from the New Zealand ascidian Pseudodistoma opacum. The structures of the metabolites were determined by analysis of mass spectrometric and 2D NMR spectroscopic data. Natural products 2 and 3, synthetic debromo analogues 8 and 9, and intermediate 16 exhibited moderate antimalarial activity toward a chloroquine-resistant strain of Plasmodium falciparum, with an IC50 range of 2.5-14 μM. The biosynthesis of 1-4 is proposed to proceed via a Pictet-Spengler condensation of 6-bromotryptamine and the α-keto acid transamination product of either arginine or homoarginine. Cell separation and 1H NMR analysis of P. opacum identified tetrahydro-β-carboline 1 to be principally located in the zooids, while fully aromatized analogues 2-4 were localized to the test.

Vanadium-uranium extraction from Wyoming vanadiferoud silicates. Report of investigations/1983

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

Hayashi, M.; Nichols, I.L.; Huiatt, J.L.

1983-11-01

The Bureau of Mines conducted laboratory studies on low-grade vanadiferous silicates from the Pumpkin Buttes and Nine Mile Lake deposits of Wyoming to examine techniques for extracting vanadium and uranium. Recovery from low-grade sources such as these could contribute to future vanadium production and reduce reliance on vanadium imports.

Effectively suppressing vanadium permeation in vanadium redox flow battery application with modified Nafion membrane with nacre-like nanoarchitectures

NASA Astrophysics Data System (ADS)

Zhang, Lesi; Ling, Ling; Xiao, Min; Han, Dongmei; Wang, Shuanjin; Meng, Yuezhong

2017-06-01

A novel self-assembled composite membrane, Nafion-[PDDA/ZrP]n with nacre-like nanostructures was successfully fabricated by a layer-by-layer (LbL) method and used as proton exchange membrane for vanadium redox flow battery applications. Poly(diallyldimethylammonium chloride) (PDDA) with positive charges and zirconium phosphate (ZrP) nanosheets with negative charges can form ultra-thin nacre-like nanostructure on the surface of Nafion membrane via the ionic crosslinking of tightly folded macromolecules. The lamellar structure of ZrP nanosheets and Donnan exclusion effect of PDDA can greatly decrease the vanadium ion permeability and improve the selectivity of proton conductivity. The fabricated Nafion-[PDDA/ZrP]4 membrane shows two orders of magnitude lower vanadium ion permeability (1.05 × 10-6 cm2 min-1) and 12 times higher ion selectivity than those of pristine Nafion membrane at room temperature. Consequently, the performance of vanadium redox flow batteries (VRFBs) assembled with Nafion-[PDDA/ZrP]3 membrane achieved a highly coulombic efficiency (CE) and energy efficiency (EE) together with a very slow self-discharge rate. When comparing with pristine Nafion VRFB, the CE and EE values of Nafion-[PDDA/ZrP]3 VRFB are 10% and 7% higher at 30 mA cm-2, respectively.

Nuclear reactor fuel element with vanadium getter on cladding

DOEpatents

Johnson, Carl E.; Carroll, Kenneth G.

1977-01-01

A nuclear reactor fuel element is described which has an outer cladding, a central core of fissionable or mixed fissionable and fertile fuel material and a layer of vanadium as an oxygen getter on the inner surface of the cladding. The vanadium reacts with oxygen released by the fissionable material during irradiation of the core to prevent the oxygen from reacting with and corroding the cladding. Also described is a method for coating the inner surface of small diameter tubes of cladding with a layer of vanadium.

Vanadium Recovery from Oil Fly Ash by Carbon Removal and Roast-Leach Process

NASA Astrophysics Data System (ADS)

Jung, Myungwon; Mishra, Brajendra

2018-02-01

This research mainly focuses on the recovery of vanadium from oil fly ash by carbon removal and the roast-leach process. The oil fly ash contained about 85% unburned carbon and 2.2% vanadium by weight. A vanadium-enriched product was obtained after carbon removal, and the vanadium content of this product was 19% by weight. Next, the vanadium-enriched product was roasted with sodium carbonate to convert vanadium oxides to water-soluble sodium metavanadate. The roasted sample was leached with water at 60°C, and the extraction percentage of vanadium was about 92% by weight. Several analytical techniques, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES), x-ray fluorescence (XRF), and thermogravimetric and differential thermal analysis (TG-DTA), were utilized for sample analyses. Thermodynamic modeling was also conducted with HSC chemistry software to explain the experimental results.

Vanadium Extraction from Shale via Sulfuric Acid Baking and Leaching

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-01-01

Fluorides are widely used to improve vanadium extraction from shale in China. Sulfuric acid baking-leaching (SABL) was investigated as a means of recovering vanadium which does not require the use of fluorides and avoids the productions of harmful fluoride-containing wastewater. Various effective factors were systematically studied and the experimental results showed that 90.1% vanadium could be leached from the shale. On the basis of phase transformations and structural changes after baking the shale, a mechanism of vanadium extraction from shale via SABL was proposed. The mechanism can be described as: (1) sulfuric acid diffusion into particles; (2) the formation of concentrated sulfuric acid media in the particles after water evaporation; (3) hydroxyl groups in the muscovite were removed and transient state [SO4 2-] was generated; and (4) the metals in the muscovite were sulfated by active [SO4 2-] and the vanadium was released. Thermodynamics modeling confirmed this mechanism.

Vanadium Oxide Thin Film Formation on Graphene Oxide by Microexplosive Decomposition of Ammonium Peroxovanadate and Its Application as a Sodium Ion Battery Anode.

PubMed

Mikhaylov, Alexey A; Medvedev, Alexander G; Grishanov, Dmitry A; Sladkevich, Sergey; Gun, Jenny; Prikhodchenko, Petr V; Xu, Zhichuan J; Nagasubramanian, Arun; Srinivasan, Madhavi; Lev, Ovadia

2018-02-27

Formation of vanadium oxide nanofilm-coated graphene oxide (GO) is achieved by thermally induced explosive disintegration of a microcrystalline ammonium peroxovanadate-GO composite. GO sheets isolate the microcrystalline grains and capture and contain the microexplosion products, resulting in the deposition of the nanoscale products on the GO. Thermal treatment of the supported nanofilm yields a sequence of nanocrystalline phases of vanadium oxide (V 3 O 7 , VO 2 ) as a function of temperature. This is the first demonstration of microexplosive disintegration of a crystalline peroxo compound to yield a nanocoating. The large number of recently reported peroxide-rich crystalline materials suggests that the process can be a useful general route for nanofilm formation. The V 3 O 7 @GO composite product was tested as a sodium ion battery anode and showed high charge capacity at high rate charge-discharge cycling (150 mAh g -1 at 3000 mA g -1 vs 300 mAh g -1 at 100 mA g -1 ) due to the nanomorphology of the vanadium oxide.

Iron diminishes the in vitro biological effect of vanadium.

EPA Science Inventory

Mechanistic pathways underlying inflammatory injury following exposures to vanadium-containing compounds are not defined. We tested the postulate that the in vitro biological effect of vanadium results from its impact on iron homeostasis. Human bronchial epithelial (HBE) cells ex...

Amphoteric Ion-Exchange Membranes with Significantly Improved Vanadium Barrier Properties for All-Vanadium Redox Flow Batteries.

PubMed

Nibel, Olga; Rojek, Tomasz; Schmidt, Thomas J; Gubler, Lorenz

2017-07-10

All-vanadium redox flow batteries (VRBs) have attracted considerable interest as promising energy-storage devices that can allow the efficient utilization of renewable energy sources. The membrane, which separates the porous electrodes in a redox flow cell, is one of the key components in VRBs. High rates of crossover of vanadium ions and water through the membrane impair the efficiency and capacity of a VRB. Thus, membranes with low permeation rate of vanadium species and water are required, also characterized by low resistance and stability in the VRB environment. Here, we present a new design concept for amphoteric ion-exchange membranes, based on radiation-induced grafting of vinylpyridine into an ethylene tetrafluoroethylene base film and a two-step functionalization to introduce cationic and anionic exchange sites, respectively. During long-term cycling, redox flow cells containing these membranes showed higher efficiency, less pronounced electrolyte imbalance, and significantly reduced capacity decay compared to the cells with the benchmark material Nafion 117. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catalytic destruction of PCDD/Fs over vanadium oxide-based catalysts.

PubMed

Yu, Ming-Feng; Lin, Xiao-Qing; Li, Xiao-Dong; Yan, Mi; Prabowo, Bayu; Li, Wen-Wei; Chen, Tong; Yan, Jian-Hua

2016-08-01

Vanadium oxide-based catalysts were developed for the destruction of vapour phase PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans). A vapour phase PCDD/Fs generating system was designed to supply stable PCDD/Fs steam with initial concentration of 3.2 ng I-TEQ Nm(-3). Two kinds of titania (nano-TiO2 and conventional TiO2) and alumina were used as catalyst supports. For vanadium-based catalysts supported on nano-TiO2, catalyst activity is enhanced with operating temperature increasing from 160 to 300 °C and then reduces with temperature rising further to 350 °C. It is mainly due to the fact that high volatility of organic compounds at 350 °C suppresses adsorption of PCDD/Fs on catalysts surface and then further inhibits the reaction between catalyst and PCDD/Fs. The optimum loading of vanadium on nano-TiO2 support is 5 wt.% where vanadium oxide presents highly dispersed amorphous state according to the Raman spectra and XRD patterns. Excessive vanadium will block the pore space and form microcrystalline V2O5 on the support surface. At the vanadium loading of 5 wt.%, nano-TiO2-supported catalyst performs best on PCDD/Fs destruction compared to Al2O3 and conventional TiO2. Chemical states of vanadium in the fresh, used and reoxidized VOx(5 %)/TiO2 catalysts at different operating temperature are also analysed by XPS.

Thymic cytoarchitecture changes in mice exposed to vanadium.

PubMed

Ustarroz-Cano, Martha; Garcia-Pelaez, Isabel; Cervantes-Yepez, Silvana; Lopez-Valdez, Nelly; Fortoul, Teresa I

2017-12-01

The thymus is a vital immune system organ wherein selection of T-lymphocytes occurs in a process regulated by dendritic and epithelial thymic cells. Previously, we have reported that in a mouse model of vanadium inhalation, a decrease in CD11c dendritic cells was observed. In the present study, we report on a thymic cortex-medulla distribution distortion in these hosts due to apparent effects of the inhaled vanadium on cytokeratin-5 (K5 + ) epithelial cells in the same mouse model - after 1, 2, and 4 weeks of exposure - by immunohistochemistry. These cells - together with dendritic cells - eliminate autoreactive T-cell clones and regulate the production of regulatory T-cells in situ. Because both cell types are involved in the negative selection of autoreactive clones, a potential for an increase in development of autoimmune conditions could be a possible consequence among individuals who might be exposed often to vanadium in air pollution, including dwellers of highly polluted cities with elevated levels of particulate matter onto which vanadium is often adsorbed.

The structural studies of vanadium substituted lithium-bismuth-boro-tellurite glass

NASA Astrophysics Data System (ADS)

Madhu, A.; Eraiah, B.

2018-05-01

The structural studies of vanadium substituted lithium-bismuth-boro-tellurite glass is successfully prepared and certain analysis like XRD,FTIR,DTA/TGA with density, molar volume are done. The amorphous phase has been identified based on X-ray diffraction analysis. The vanadium oxide plays the role as a glass-modifier and influences on BO3 ↔ BO4 conversion. The observed nonlinear variation in Tg with vanadium oxide increase, it reflects structural changes. The nonlinear variation of density and molar volume can be attributed to vanadium oxide incorporation have increased the number of Non-bridging oxygen (NBO'S).

Geochemistry of vanadium (V) in Chinese coals.

PubMed

Liu, Yuan; Liu, Guijian; Qu, Qinyuan; Qi, Cuicui; Sun, Ruoyu; Liu, Houqi

2017-10-01

Vanadium in coals may have potential environmental and economic impacts. However, comprehensive knowledge of the geochemistry of V in coals is lacking. In this study, abundances, distribution and modes of occurrence of V are reviewed by compiling >2900 reported Chinese coal samples. With coal reserves in individual provinces as the weighting factors, V in Chinese coals is estimated to have an average abundance of 35.81 μg/g. Large variation of V concentration is observed in Chinese coals of different regions, coal-forming periods, and maturation ranks. According to the concentration coefficient of V in coals from individual provinces, three regions are divided across Chinese coal deposits. Vanadium in Chinese coals is probably influenced by sediment source and sedimentary environment, supplemented by late-stage hydrothermal fluids. Specifically, hydrothermal fluids have relatively more significant effect on the enrichment of V in local coal seams. Vanadium in coals is commonly associated with aluminosilicate minerals and organic matter, and the modes of V occurrence in coal depend on coal-forming environment and coal rank. The Chinese V emission inventory during coal combustion is estimated to be 4906 mt in 2014, accounting for 50.55 % of global emission. Vanadium emissions by electric power plants are the largest contributor.

Consolidation and fabrication techniques for vanadium-20 w/o titanium /TV-20/

NASA Technical Reports Server (NTRS)

Burt, W. R.; Karasek, F. J.; Kramer, W. C.; Mayfield, R. M.; Mc Gowan, R. D.

1968-01-01

Tests of the mechanical properties, fuel compatibility, sodium corrosion and irradiation behavior were made for vanadium and vanadium alloy. Improved methods for consolidation and fabrication of bar, rod, sheet, and high-quality, small diameter, thin-wall tubing of vanadium-20 without titanium are reported.

ANISEED 2017: extending the integrated ascidian database to the exploration and evolutionary comparison of genome-scale datasets.

PubMed

Brozovic, Matija; Dantec, Christelle; Dardaillon, Justine; Dauga, Delphine; Faure, Emmanuel; Gineste, Mathieu; Louis, Alexandra; Naville, Magali; Nitta, Kazuhiro R; Piette, Jacques; Reeves, Wendy; Scornavacca, Céline; Simion, Paul; Vincentelli, Renaud; Bellec, Maelle; Aicha, Sameh Ben; Fagotto, Marie; Guéroult-Bellone, Marion; Haeussler, Maximilian; Jacox, Edwin; Lowe, Elijah K; Mendez, Mickael; Roberge, Alexis; Stolfi, Alberto; Yokomori, Rui; Brown, C Titus; Cambillau, Christian; Christiaen, Lionel; Delsuc, Frédéric; Douzery, Emmanuel; Dumollard, Rémi; Kusakabe, Takehiro; Nakai, Kenta; Nishida, Hiroki; Satou, Yutaka; Swalla, Billie; Veeman, Michael; Volff, Jean-Nicolas; Lemaire, Patrick

2018-01-04

ANISEED (www.aniseed.cnrs.fr) is the main model organism database for tunicates, the sister-group of vertebrates. This release gives access to annotated genomes, gene expression patterns, and anatomical descriptions for nine ascidian species. It provides increased integration with external molecular and taxonomy databases, better support for epigenomics datasets, in particular RNA-seq, ChIP-seq and SELEX-seq, and features novel interactive interfaces for existing and novel datatypes. In particular, the cross-species navigation and comparison is enhanced through a novel taxonomy section describing each represented species and through the implementation of interactive phylogenetic gene trees for 60% of tunicate genes. The gene expression section displays the results of RNA-seq experiments for the three major model species of solitary ascidians. Gene expression is controlled by the binding of transcription factors to cis-regulatory sequences. A high-resolution description of the DNA-binding specificity for 131 Ciona robusta (formerly C. intestinalis type A) transcription factors by SELEX-seq is provided and used to map candidate binding sites across the Ciona robusta and Phallusia mammillata genomes. Finally, use of a WashU Epigenome browser enhances genome navigation, while a Genomicus server was set up to explore microsynteny relationships within tunicates and with vertebrates, Amphioxus, echinoderms and hemichordates. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Optimization of cultivation conditions of fermented shaggy ink cap culinary-medicinal mushroom, Coprinus comatus (O.Mull.:Fr.) Pers. (higher Basidiomycetes) rich in Vanadium.

PubMed

Zhang, Chunjing; Qi, Xiaodan; Shi, Yan; Sun, Yan; Li, Shuyan; Gao, Xiulan; Yu, Haitao

2012-01-01

The present paper is mainly aimed at optimization of cultivation conditions of fermented mushrooms of Coprinus comatus rich in vanadium (CCRV). Initial screening of effects of carbon source, temperature, pH, and inoculum size were done by using a one-factor-at-a-time method. The results obtained in that study showed that the optimal medium composition was 30 g glucose/Lin YEPG medium, initial pH 6.0, inoculum volume 10%, and incubation time 120 h. Then the medium was subjected to screening of the most significant parameters using the L9 orthogonal array to solve multivariable equations simultaneously. The results obtained in this study showed that the optimal medium composition was 0.4% V and 30 g glucose/Lin YEPG medium, initial pH 5.0, inoculum volume 15%, and incubation time 120 h. At this medium composition, the mycelial biomass and V content were 7.18 ± 0.24 g/L and 3786.0 ± 17 μg/g, respectively. The anti-diabetic potential of CCRV produced with the optimal level was tested in alloxan-induced diabetes. After the mice were administered (i.g.) with CCRV, the level of blood sugar in the CCRV group was very close to that of the control group. These findings suggested that CCRV produced with the optimal level is useful in the control of diabetes mellitus.

CATALYTIC PROMOTION OF THE ADSORPTION OF VANADIUM ON AN ANIONIC EXCHANGE RESIN

DOEpatents

Bailes, R.H.; Ellis, D.A.

1958-08-26

An improvement in the process for the recovery of vanadium from acidic phosphatic solutions is presented. In this process the vanadium is first oxidized to the pentavaleat state, and is then separated by contacting such solutions with an anion exchange resin whereby adsorption of the complexed pentavalent vanadium is effected. The improvement lies in the fact that adsorp tion of the vanadium complex by the anion exchange resin is promoted and improved by providing fiuoride ions in solution to be contacted.

[Effect of vanadium exposure on neurobehavioral function in workers].

PubMed

Zhu, C W; Liu, Y X; Huang, C J; Gao, W; Hu, G L; Li, J; Zhang, Q; Lan, Y J

2016-02-20

To establish the comprehensive indicators for neurobehavioral function test, and to investigate the possible adverse effect of long-time vanadium exposure on neurobehavioral function and its features in workers. From July to November, 2012, The Neurobehavioral Core Test Battery(NCTB) recommended by WHO was used to conduct tests for 128 workers in vanadium exposure group and 128 workers in control group. The t-test and analysis of covariance were used to compare the differences in each indicator in NCTB between different populations, and the principal component analysis was used to establish the comprehensive neurobehavioral index(NBI) and investigate the effect of vanadium on workers' neurobehavioral function. The vanadium exposure group had significantly lower visual retention score(6.9±1.9), digit span(order) score(8.9±2.9), lifting and turning dexterity(the non-handed hand) score (14.1±3.6), pursuit aiming test(the number of correct dots) score(65.7±24.8), and digit symbol score (31.1±15.0) than the control group (8.2±1.3, 9.4±2.7, 15.5±3.0, 76.5±23.8, and 33.7±9.5)(all P<0.05). The vanadium exposure group also had a significantly lower NBI than the control group(-0.167±0.602 vs 0.168±0.564, P<0.05). Long-term vanadium exposure can influence the workers' neurobehavioral function, with the manifestations of decreased hearing and visual memory, movement velocity, accuracy, and coordination.

Theoretical analysis and experiments for the carburization of vanadium-bearing hot metal

NASA Astrophysics Data System (ADS)

Ma, Deng; Wu, Wei; Dai, Shifan; Liu, Zhibin

2018-01-01

In this study, the feasibility of the carburization of vanadium-bearing hot metal was first investigated by thermodynamic analysis. Next, three carburizers, namely a low-nitrogen carburizer, anthracite, and coke, were used for carburization of 500 g of vanadium-bearing hot metal at 1450 °C, 1500 °C, and 1550 °C, respectively. The carbon increments for the low-nitrogen carburizer, anthracite and coke followed decreasing order in the temperature range from 1450 °C to 1550 °C. Anthracite was the most cost-effective carburizer. Hence, anthracite is used in pilot-scale experiments of the vanadium-bearing hot metal (100 kg and 200 kg). Finally, vanadium extraction experiments of the vanadium-bearing hot metal were carried out in a top-bottom-combined blowing induction furnace. It is proved that the average superheat degree of semi-steel increases from 100 °C to 198 °C by the carburization of vanadium-containing hot metal. Foundation Item: Item Sponsored by National Science Foundation of China (51674092)

Imaging of Vanadium in Microfossils: A New Potential Biosignature

NASA Astrophysics Data System (ADS)

Marshall, Craig P.; Marshall, Alison Olcott; Aitken, Jade B.; Lai, Barry; Vogt, Stefan; Breuer, Pierre; Steemans, Philippe; Lay, Peter A.

2017-11-01

The inability to unambiguously distinguish the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from nonbiological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This, too, is important for the search for life on Mars by in situ analyses via rovers or sample return missions for future analysis here on Earth. Here, we report the application of synchrotron X-ray fluorescence imaging of vanadium, within thermally altered organic-walled microfossils of bona fide biological origin. From our data, we demonstrate that vanadium is present within microfossils of undisputable biological origin. It is well known in the organic geochemistry literature that elements such as vanadium are enriched and contained within crude oils, asphalts, and black shales that have been formed by diagenesis of biological organic material. It has been demonstrated that the origin of vanadium is due to the diagenetic alteration of precursor chlorophyll and heme porphyrin pigment compounds from living organisms. We propose that, taken together, microfossil-like morphology, carbonaceous composition, and the presence of vanadium could be used in tandem as a biosignature to ascertain the biogenicity of putative microfossil-like structures.

Vanadium proton exchange membrane water electrolyser

NASA Astrophysics Data System (ADS)

Noack, Jens; Roznyatovskaya, Nataliya; Pinkwart, Karsten; Tübke, Jens

2017-05-01

In order to reverse the reactions of vanadium oxygen fuel cells and to regenerate vanadium redox flow battery electrolytes that have been oxidised by atmospheric oxygen, a vanadium proton exchange membrane water electrolyser was set up and investigated. Using an existing cell with a commercial and iridium-based catalyst coated membrane, it was possible to fully reduce V3.5+ and V3+ solutions to V2+ with the formation of oxygen and with coulomb efficiencies of over 96%. The cell achieved a maximum current density of 75 mA/cm2 during this process and was limited by the proximity of the V(III) reduction to the hydrogen evolution reaction. Due to the specific reaction mechanisms of V(IV) and V(III) ions, V(III) solutions were reduced with an energy efficiency of 61%, making this process nearly twice as energy efficient as the reduction of V(IV) to V(III). Polarisation curves and electrochemical impedance spectroscopy were used to further investigate the losses of half-cell reactions and to find ways of further increasing efficiency and performance levels.

Characterization of Non-Innocent Metal Complexes Using Solid-State NMR Spectroscopy: o-Dioxolene Vanadium Complexes

PubMed Central

Chatterjee, Pabitra B.; Goncharov-Zapata, Olga; Quinn, Laurence L.; Hou, Guangjin; Hamaed, Hiyam; Schurko, Robert W.; Polenova, Tatyana; Crans, Debbie C.

2012-01-01

51V solid-state NMR (SSNMR) studies of a series of non-innocent vanadium(V) catechol complexes have been conducted to evaluate the possibility that 51V NMR observables, quadrupolar and chemical shift anisotropies, and electronic structures of such compounds can be used to characterize these compounds. The vanadium(V) catechol complexes described in these studies have relatively small quadrupolar coupling constants, which cover a surprisingly small range from 3.4 to 4.2 MHz. On the other hand, isotropic 51V NMR chemical shifts cover a wide range from −200 ppm to 400 ppm in solution and from −219 to 530 ppm in the solid state. A linear correlation of 51V NMR isotropic solution and solid-state chemical shifts of complexes containing non-innocent ligands is observed. These experimental results provide the information needed for the application of 51V SSNMR spectroscopy in characterizing the electronic properties of a wide variety of vanadium-containing systems, and in particular those containing non-innocent ligands and that have chemical shifts outside the populated range of −300 ppm to −700 ppm. The studies presented in this report demonstrate that the small quadrupolar couplings covering a narrow range of values reflect the symmetric electronic charge distribution, which is also similar across these complexes. These quadrupolar interaction parameters alone are not sufficient to capture the rich electronic structure of these complexes. In contrast, the chemical shift anisotropy tensor elements accessible from 51V SSNMR experiments are a highly sensitive probe of subtle differences in electronic distribution and orbital occupancy in these compounds. Quantum chemical (DFT) calculations of NMR parameters for [VO(hshed)(Cat)] yield 51V CSA tensor in reasonable agreement with the experimental results, but surprisingly, the calculated quadrupolar coupling constant is significantly greater than the experimental value. The studies demonstrate that substitution of the

A nested case-control study of prenatal vanadium exposure and low birthweight.

PubMed

Jiang, Minmin; Li, Yuanyuan; Zhang, Bin; Zhou, Aifen; Zheng, Tongzhang; Qian, Zhengmin; Du, Xiaofu; Zhou, Yanqiu; Pan, Xinyun; Hu, Jie; Wu, Chuansha; Peng, Yang; Liu, Wenyu; Zhang, Chuncao; Xia, Wei; Xu, Shunqing

2016-09-01

Is prenatal vanadium exposure associated with adverse birth outcomes? The odds of low birthweight (LBW) are increased 2.23-fold in mothers with a urinary vanadium of ≥2.91 μg/g creatinine compared with that in mothers with a urinary vanadium of ≤1.42 μg/g creatinine. Human exposure to vanadium occurs through intake of food, water and polluted air. Vanadium has been suggested to have fetotoxicity and developmental toxicity in animal studies, and epidemiological studies have reported an association between a decrease in birthweight and vanadium exposure estimated from particulate matter. A nested case-control study involving 816 study participants (204 LBW cases and 612 matched controls) was conducted with data from the prospective Healthy Baby Cohort between 2012 and 2014 in the province of Hubei, China. Vanadium concentrations in 816 maternal urine samples collected before delivery [the median gestational age was 39 weeks (range 27-42 weeks)] were measured by inductively coupled plasma mass spectrometry. Information on the infants' birth outcomes was obtained from medical records. Conditional logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs). The median urinary vanadium concentration of the cases was much higher than that of the controls (3.04 μg/g creatinine versus 1.93 μg/g creatinine). The results revealed a significant positive trend between the odds of LBW and level of maternal urinary vanadium [relative to the lowest tertile; adjusted OR = 1.69 (95% CI: 0.92, 3.10) for the medium tertile; adjusted OR = 2.23 (95% CI: 1.23, 4.05) for the highest tertile; P-trend = 0.02]. Additionally, the association was not modified by maternal age (P for heterogeneity = 0.70) or infant gender (P for heterogeneity = 0.21). The maternal urine sample was collected before labor, and the maternal urinary vanadium levels measured at one point in time may not accurately reflect the vanadium burden during the entire pregnancy

Plasma assisted synthesis of vanadium pentoxide nanoplates

NASA Astrophysics Data System (ADS)

Singh, Megha; Sharma, Rabindar Kumar; Kumar, Prabhat; Reddy, G. B.

2015-08-01

In this work, we report the growth of α-V2O5 (orthorhombic) nanoplates on glass substrate using plasma assisted sublimation process (PASP) and Nickel as catalyst. 100 nm thick film of Ni is deposited over glass substrate by thermal evaporation process. Vanadium oxide nanoplates have been deposited treating vanadium metal foil under high vacuum conditions with oxygen plasma. Vanadium foil is kept at fixed temperature growth of nanoplates of V2O5 to take place. Samples grown have been studied using XPS, XRD and HRTEM to confirm the growth of α-phase of V2O5, which revealed pure single crystal of α- V2O5 in orthorhombic crystallographic plane. Surface morphological studies using SEM and TEM show nanostructured thin film in form of plates. Uniform, vertically aligned randomly oriented nanoplates of V2O5 have been deposited.

Vanadium Nitrogenase Reduces CO*

PubMed Central

Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W.

2011-01-01

Vanadium nitrogenase not only reduces dinitrogen to ammonia but also reduces carbon monoxide to ethylene, ethane, and propane. The parallelism between the two reactions suggests a potential link in mechanism and evolution between the carbon and nitrogen cycles on Earth. PMID:20689010

Vanadium Exposure-Induced Neurobehavioral Alterations among Chinese Workers

PubMed Central

Li, Hong; Zhou, Dinglun; Zhang, Qin; Feng, Chengyong; Zheng, Wei; He, Keping; Lan, Yajia

2014-01-01

Vanadium-containing products are manufactured and widely used in the modern industry. Yet the neurobehavioral toxicity due to occupational exposure to vanadium remained elusive. This cross-sectional study was designed to examine the neurotoxic effects of occupational vanadium exposure. A total of 463 vanadium-exposed workers (exposed group) and 251 non-exposed workers (control group) were recruited from a Steel and Iron Group in Sichuan, China. A WHO-recommended neurobehavioral core test battery (NCTB) and event-related auditory evoked potentials test (P300) were used to assess the neurobehavioral functions of all study subjects. A general linear model was used to compare outcome scores between the two groups while controlling for possible confounders. The exposed group showed a statistically significant neurobehavioral alteration more than the control group in the NCTB tests. The exposed workers also exhibited an increased anger-hostility, depression-dejection and fatigue-inertia on the profile of mood states (p<0.05). Performances in the Simple Reaction Time, Digit Span, Benton Visual Retention and Pursuit Aiming were also poorer among exposed workers as compared to unexposed control workers(p<0.05). Some of these poor performances in tests were also significantly related to workers’ exposure duration. P300 latencies were longer in the exposed group than in the control (p<0.05). Longer mean reaction times and more counting errors were also found in the exposed workers (p<0.05). Given the findings of our study and the limitations of neurobehavioral workplace testing, we found evidence of altered neurobehavioral outcomes by occupational exposure to vanadium. PMID:23500660

A Disposable Alkaline Phosphatase-Based Biosensor for Vanadium Chronoamperometric Determination

PubMed Central

Alvarado-Gámez, Ana Lorena; Alonso-Lomillo, María Asunción; Domínguez-Renedo, Olga; Arcos-Martínez, María Julia

2014-01-01

A chronoamperometric method for vanadium ion determination, based on the inhibition of the enzyme alkaline phosphatase, is reported. Screen-printed carbon electrodes modified with gold nanoparticles were used as transducers for the immobilization of the enzyme. The enzymatic activity over 4-nitrophenyl phosphate sodium salt is affected by vanadium ions, which results in a decrease in the chronoamperometric current registered. The developed method has a detection limit of 0.39 ± 0.06 μM, a repeatability of 7.7% (n = 4) and a reproducibility of 8% (n = 3). A study of the possible interferences shows that the presence of Mo(VI), Cr(III), Ca(II) and W(VI), may affect vanadium determination at concentration higher than 1.0 mM. The method was successfully applied to the determination of vanadium in spiked tap water. PMID:24569772

Imaging of Vanadium in Microfossils: A New Potential Biosignature

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

Marshall, Craig P.; Marshall, Alison Olcott; Aitken, Jade B.

Being able to distinguish unambiguously the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from non-biological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This too, is important for the search for life on Mars; either by in situ analyses via rovers, or sample return missions for future analysis here on Earth. Here, we report the application of synchrotron X-ray fluorescence imaging of vanadium, within thermally altered organic-walled microfossils of bona fide biologicalmore » origin. From our data, we demonstrate that vanadium is present within microfossils of undisputable biological origin. It is well known in the organic geochemistry literature, that elements such as vanadium are enriched and contained within crude oils, asphalts, and black shales that have been formed by diagensis of biological organic material. It has been demonstrated that the origin of vanadium is due to the diagenetic alteration of precursor chlorophyll and heme porphyrin pigment compounds from living organisms. Here, we propose that taken together, microfossil-like morphology, carbonaceous composition, and the presence of vanadium could be used in tandem as a biosignature to ascertain the biogenecity of putative microfossil-like structures.« less

Imaging of Vanadium in Microfossils: A New Potential Biosignature

DOE PAGES

Marshall, Craig P.; Marshall, Alison Olcott; Aitken, Jade B.; ...

2017-11-01

Being able to distinguish unambiguously the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from non-biological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This too, is important for the search for life on Mars; either by in situ analyses via rovers, or sample return missions for future analysis here on Earth. Here, we report the application of synchrotron X-ray fluorescence imaging of vanadium, within thermally altered organic-walled microfossils of bona fide biologicalmore » origin. From our data, we demonstrate that vanadium is present within microfossils of undisputable biological origin. It is well known in the organic geochemistry literature, that elements such as vanadium are enriched and contained within crude oils, asphalts, and black shales that have been formed by diagensis of biological organic material. It has been demonstrated that the origin of vanadium is due to the diagenetic alteration of precursor chlorophyll and heme porphyrin pigment compounds from living organisms. Here, we propose that taken together, microfossil-like morphology, carbonaceous composition, and the presence of vanadium could be used in tandem as a biosignature to ascertain the biogenecity of putative microfossil-like structures.« less

Two-Stage Separation of V(IV) and Al(III) by Crystallization and Solvent Extraction from Aluminum-Rich Sulfuric Acid Leaching Solution of Stone Coal

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing; Liu, Hong

2017-10-01

To improve separation of V(IV) and Al(III) from aluminum-rich sulfuric acid leaching solution of stone coal, the two-stage separation by crystallization and solvent extraction methods have been developed. A co-extraction coefficient ( k) was put forward to evaluate comprehensively co-extraction extent in different solutions. In the crystallization stage, 68.2% of aluminum can be removed from the solution. In the solvent extraction stage, vanadium was selectively extracted using di-2-ethylhexyl phosphoric acid/tri-n-butyl phosphate from the crystalline mother solution, followed by H2SO4 stripped efficiently. A V2O5 product with purity of 98.39% and only 0.10% Al was obtained after oxidation, precipitation, and calcination. Compared with vanadium extraction from solution without crystallization, the counter-current extraction stage of vanadium can be decreased from 6 to 3 and co-extraction coefficient ( k) decreased from 2.51 to 0.58 with two-stage separation. It is suggested that the aluminum removal by crystallization can evidently weaken the influence of aluminum co-extraction on vanadium extraction and improve the selectivity of solvent extraction for vanadium.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

Properties of vanadium-loaded iron sorbent after alkali regeneration.

PubMed

Khalid, Muhammad Kamran; Leiviskä, Tiina; Tanskanen, Juha

2017-11-01

The aim of this research was to investigate the regeneration and reuse of a commercial granular iron sorbent (mainly goethite) when used in vanadium removal. A regeneration rate of 3 M NaOH was the highest (85%) achieved, followed by 2 M NaOH (79%) and 1 M NaOH (68%). The breakthrough curves show that the regenerated material can be reused. The BET (Brunauer-Emmett-Teller) surface area increased by 35-38% and the total pore volume increased by 123-130% as a consequence of NaOH treatment. The results indicated that sodium hydroxide could be used for the regeneration of iron sorbent although the regeneration was incomplete. This may be explained by the fact that vanadium diffusion into pores is a significant sorption mechanism in addition to complex formation with surface functional groups. As a consequence, vanadium desorbability from pores is not as effective as the regeneration of surface sites. X-ray photoelectron spectroscopy analyses confirmed a very low vanadium content on the surface of the NaOH-treated iron sorbent.

Vanadium removal from LD converter slag using bacteria and fungi.

PubMed

Mirazimi, S M J; Abbasalipour, Z; Rashchi, F

2015-04-15

Removal of vanadium from Linz-Donawits (LD) converter slag was investigated by means of three different species of microbial systems: Acidithiobacillus thiooxidans (autotrophic bacteria), Pseudomonas putida (heterotrophic bacteria) and Aspergillus niger (fungi). The bioleaching process was carried out in both one-step and two-step process and the leaching efficiencies in both cases were compared. Formation of inorganic and organic acids during the leaching process caused mobilization of vanadium. In order to reduce toxic effects of the metal species on the above mentioned microorganisms, a prolonged adaptation process was performed. Both bacteria, A. thiooxidans and P. putida were able to remove more than 90% of vanadium at slag concentrations of 1-5 g L(-1) after 15 days. Also, the maximum achievable vanadium removal in the fungal system was approximately 92% at a slag concentration of 1 g L(-1) after 22 days. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental and theoretical study of the reactions between neutral vanadium oxide clusters and ethane, ethylene, and acetylene.

PubMed

Dong, Feng; Heinbuch, Scott; Xie, Yan; Rocca, Jorge J; Bernstein, Elliot R; Wang, Zhe-Chen; Deng, Ke; He, Sheng-Gui

2008-02-13

Reactions of neutral vanadium oxide clusters with small hydrocarbons, namely C2H6, C2H4, and C2H2, are investigated by experiment and density functional theory (DFT) calculations. Single photon ionization through extreme ultraviolet (EUV, 46.9 nm, 26.5 eV) and vacuum ultraviolet (VUV, 118 nm, 10.5 eV) lasers is used to detect neutral cluster distributions and reaction products. The most stable vanadium oxide clusters VO2, V2O5, V3O7, V4O10, etc. tend to associate with C2H4 generating products V(m)O(n)C2H4. Oxygen-rich clusters VO3(V2O5)(n=0,1,2...), (e.g., VO3, V3O8, and V5O13) react with C2H4 molecules to cause a cleavage of the C=C bond of C2H4 to produce (V2O5)(n)VO2CH2 clusters. For the reactions of vanadium oxide clusters (V(m)O(n)) with C2H2 molecules, V(m)O(n)C2H2 are assigned as the major products of the association reactions. Additionally, a dehydration reaction for VO3 + C2H2 to produce VO2C2 is also identified. C2H6 molecules are quite stable toward reaction with neutral vanadium oxide clusters. Density functional theory calculations are employed to investigate association reactions for V2O5 + C2H(x). The observed relative reactivity of C2 hydrocarbons toward neutral vanadium oxide clusters is well interpreted by using the DFT calculated binding energies. DFT calculations of the pathways for VO3+C2H4 and VO3+C2H2 reaction systems indicate that the reactions VO3+C2H4 --> VO2CH2 + H2CO and VO3+C2H2 --> VO2C2 + H2O are thermodynamically favorable and overall barrierless at room temperature, in good agreement with the experimental observations.

The Hemolymph of the ascidian Styela plicata (Chordata-Tunicata) contains heparin inside basophil-like cells and a unique sulfated galactoglucan in the plasma.

PubMed

de Barros, Cintia M; Andrade, Leonardo R; Allodi, Silvana; Viskov, Christian; Mourier, Pierre A; Cavalcante, Moisés C M; Straus, Anita H; Takahashi, Helio K; Pomin, Vitor H; Carvalho, Vinicius F; Martins, Marco A; Pavão, Mauro S G

2007-01-19

The hemolymph of ascidians (Chordata-Tunicata) contains different types of hemocytes embedded in a liquid plasma. In the present study, heparin and a sulfated heteropolysaccharide were purified from the hemolymph of the ascidian Styela plicata. The heteropolysaccharide occurs free in the plasma, is composed of glucose ( approximately 60%) and galactose ( approximately 40%), and is highly sulfated. Heparin, on the other hand, occurs in the hemocytes, and high performance liquid chromatography of the products formed by degradation with specific lyases revealed that it is composed mainly by the disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4)) (39.7%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(6SO(4)) (38.2%). Small amounts of the 3-O-sulfated disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4)) (9.8%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4))(6SO(4)) (3.8%) were also detected. These 3-O-sulfated disaccharides were demonstrated to be essential for the binding of the hemocyte heparin to antithrombin III. Electron microscopy techniques were used to characterize the ultrastructure of the hemocytes and to localize heparin and histamine in these cells. At least five cell types were recognized and classified as univacuolated and multivacuolated cells, amebocytes, hemoblasts, and granulocytes. Immunocytochemistry showed that heparin and histamine co-localize in intracellular granules of only one type of hemocyte, the granulocyte. These results show for the first time that in ascidians, a sulfated galactoglucan circulates free in the plasma, and heparin occurs as an intracellular product of a circulating basophil-like cell.

Construction of a cDNA microarray derived from the ascidian Ciona intestinalis.

PubMed

Azumi, Kaoru; Takahashi, Hiroki; Miki, Yasufumi; Fujie, Manabu; Usami, Takeshi; Ishikawa, Hisayoshi; Kitayama, Atsusi; Satou, Yutaka; Ueno, Naoto; Satoh, Nori

2003-10-01

A cDNA microarray was constructed from a basal chordate, the ascidian Ciona intestinalis. The draft genome of Ciona has been read and inferred to contain approximately 16,000 protein-coding genes, and cDNAs for transcripts of 13,464 genes have been characterized and compiled as the "Ciona intestinalis Gene Collection Release I". In the present study, we constructed a cDNA microarray of these 13,464 Ciona genes. A preliminary experiment with Cy3- and Cy5-labeled probes showed extensive differential gene expression between fertilized eggs and larvae. In addition, there was a good correlation between results obtained by the present microarray analysis and those from previous EST analyses. This first microarray of a large collection of Ciona intestinalis cDNA clones should facilitate the analysis of global gene expression and gene networks during the embryogenesis of basal chordates.

Vanadium doped tin dioxide as a novel sulfur dioxide sensor.

PubMed

Das, S; Chakraborty, S; Parkash, O; Kumar, D; Bandyopadhyay, S; Samudrala, S K; Sen, A; Maiti, H S

2008-04-15

Considering the short-term exposure limit of SO2 to be 5 ppm, we first time report that semiconductor sensors based on vanadium doped SnO2 can be used for SO2 leak detection because of their good sensitivity towards SO2 at concentrations down to 5 ppm. Such sensors are quite selective in presence of other gases like carbon monoxide, methane and butane. The high sensitivity of vanadium doped tin dioxide towards SO2 may be understood by considering the oxidation of sulfur dioxide to sulfur trioxide on SnO2 surface through redox cycles of vanadium-sulfur-oxygen adsorbed species.

Quantitative LIBS analysis of vanadium in samples of hexagonal mesoporous silica catalysts.

PubMed

Pouzar, Miloslav; Kratochvíl, Tomás; Capek, Libor; Smoláková, Lucie; Cernohorský, Tomás; Krejcová, Anna; Hromádko, Ludek

2011-02-15

The method for the analysis of vanadium in hexagonal mesoporous silica (V-HMS) catalysts using Laser Induced Breakdown Spectrometry (LIBS) was suggested. Commercially available LIBS spectrometer was calibrated with the aid of authentic V-HMS samples previously analyzed by ICP OES after microwave digestion. Deposition of the sample on the surface of adhesive tape was adopted as a sample preparation method. Strong matrix effect connected with the catalyst preparation technique (1st vanadium added in the process of HMS synthesis, 2nd already synthesised silica matrix was impregnated by vanadium) was observed. The concentration range of V in the set of nine calibration standards was 1.3-4.5% (w/w). Limit of detection was 0.13% (w/w) and it was calculated as a triple standard deviation from five replicated determinations of vanadium in the real sample with a very low vanadium concentration. Comparable results of LIBS and ED XRF were obtained if the same set of standards was used for calibration of both methods and vanadium was measured in the same type of real samples. LIBS calibration constructed using V-HMS-impregnated samples failed for measuring of V-HMS-synthesized samples. LIBS measurements seem to be strongly influenced with different chemical forms of vanadium in impregnated and synthesised samples. The combination of LIBS and ED XRF is able to provide new information about measured samples (in our case for example about procedure of catalyst preparation). Copyright © 2010 Elsevier B.V. All rights reserved.

In vitro and in vivo efficacy of drugs against the protozoan parasite Azumiobodo hoyamushi that causes soft tunic syndrome in the edible ascidian Halocynthia roretzi (Drasche).

PubMed

Park, K H; Zeon, S-R; Lee, J-G; Choi, S-H; Shin, Y K; Park, K-I

2014-04-01

It was discovered recently that infection by a protozoan parasite, Azumiobodo hoyamushi, is the most probable cause for soft tunic syndrome in an edible ascidian, Halocynthia roretzi (Drasche). In an attempt to develop measures to eradicate the causative parasite, various drugs were tested for efficacy in vitro and in vivo. Of the 20 antiprotozoal drugs having different action mechanisms, five were found potent (24-h EC50  < 10 mg L(-1) ) in their parasite-killing effects: formalin, H2 O2 , bithionol, ClO2 and bronopol. Moderately potent drugs (10 < 24-h EC50  < 100 mg L(-1) ) were quinine, fumagillin, amphotericin B, ketoconazole, povidone-iodine, chloramine-T and benzalkonium chloride. Seven compounds, metronidazole, albendazole, paromomycin, nalidixic acid, sulfamonomethoxine, KMnO4 , potassium monopersulphate and citric acid, exhibited EC50  > 100 mg L(-1) . When ascidians were artificially infected with A. hoyamushi, treated using 40 mg L(-1) formalin, bronopol, ClO2 , or H2 O2 for 1 h and then monitored for 24 h, very low mortality was observed. However, the number of surviving parasite cells in the ascidian tunic tissues was significantly reduced by treating with 40 mg L(-1) formalin or ClO2 for 1 h. The data suggest that we might be able to develop a disinfection measure using a treatment regimen involving commonly available drugs. © 2013 John Wiley & Sons Ltd.

Effect of diet composition on vanadium toxicity for the chick

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

Berg, L.R.

1966-01-01

Studies to determine the effect of diet composition on the toxicity of 20 ppm added vanadium for the young chick have shown: growth depression of 25-30% with a corn-soybean meal ration but only 3-7% with a corn-herring fish meal diet. Growth depression of 35-40% with a semi-purified sucrose-soybean meal diet and approximately 50% with a diet of sucrose and herring fish meal. Adding graded levels of corn to the sucrose-fish meal ration and fish meal to the corn-soybean meal ration reduced vanadium toxicity. The corn fractions, ash, oil, starch, zein and gluten did not reduce vanadium toxicity. Removing the addedmore » magnesium (300 ppm) and potassium (2000 ppm) from the sucrose-fish meal ration did not affect growth rate or mortality. However removal of these materials from the basal ration increased growth depression due to added vanadium from 43-56% and increased mortality from 10-80%. 4 references, 9 tables.« less

Oxidative transformation of a tunichrome model compound provides new insight into the crosslinking and defense reaction of tunichromes.

PubMed

Abebe, Adal; Kuang, Qun F; Evans, Jason; Robinson, William E; Sugumaran, Manickam

2017-04-01

Tunichromes, small oligopeptides with dehydrodopa units isolated from the blood cells of ascidians, have been implicated in the defense reactions, metal binding, wound repair, or tunic formation. Their instability and high reactivity has severely hampered the assessment of their biological role. Experiments conducted with the model compound, 1,2-dehydro-N-acetyldopamine, indicated that the instability of tunichromes is due to this basic structure. Exposure of this catecholamine derivative to even mild alkaline condition such as pH 7.5 causes rapid nonenzymatic oxidation. High performance liquid chromatography and mass spectrometry studies confirmed the production of dimeric and other oligomeric products in the reaction mixture. The nonenzymatic reaction seemed to proceed through the intermediary formation of semiquinone free radical and superoxide anion. Ultraviolet and visible spectral studies associated with the oxidation of tunichromes isolated from Ascidia nigra by tyrosinase indicated the probable formation of oligomeric tunichrome products. Attempts to monitor the polymerization reaction by mass spectrometry ended in vain. Tunichrome also exhibited instability in mild alkaline conditions generating superoxide anions. Based on these studies, a possible role for oxidative transformation of tunichrome in defense reaction, tunic formation and wound healing is proposed. Copyright © 2017 Elsevier Inc. All rights reserved.

Rate Dependency of Silver Vanadium Phosphorous Oxide Reduction

NASA Astrophysics Data System (ADS)

Cheng, Po-Jen

2011-12-01

The silver vanadium phosphorus oxide (Ag2VO2PO 4) is a high-capacity and good-compatibility material for the cathode in the battery. Due to their innovative properties, they are used as cathode in lithium batteries. Therefore, when the lithium batteries begin to discharge, the anodes of the cell perform an electrochemical oxidation and release electrons. In the mean time, the cathodes in the cells perform the electrochemical reduction and catch the electrons. For reduction of Ag2VO2PO 4, two silver ions (Ag+) catch two electrons to form silver particles, and the vanadium ions (V5+) catch two electrons to form V3+. It means that four electrons will be released by lithium anode. We call this four electrons discharge as 100% discharge. In my most of the projects, the Ag2VO2PO4 material is tested by differential scanning calorimetry (DSC) to check purity. My study is based on the discharge of batteries, and I focus on the morphology and the intensity of silver particles on the cathode after discharge. Depending on different adjustment of factors, such as discharge time, discharge rate, storage time, storage temperature, I try to investigate the silver intensity, conductivity as a function of DOD (Depth of Discharge). The silver particles could be examined by optical microscope, and scanning electron microscope (SEM). Moreover, I do some x-ray diffraction analysis to quantify the silver particles after discharge. Also, I perform magnetic susceptibility measurement to check the mechanism of the reduction of vanadium ions. Under the research on silver ions and vanadium ions, I will know a big frame of reduction process on silver vanadium phosphorous oxide and the time effect on this cathode material.

Proceraea exoryxae sp. nov. (Annelida, Syllidae, Autolytinae), the first known polychaete miner tunneling into the tunic of an ascidian

PubMed Central

Nygren, Arne

2017-01-01

While studying organisms living in association with the solitary tunicate Phallusia nigra (Ascidiacea, Ascidiidae) from a shallow fringing reef at Zeytouna Beach (Egyptian Red Sea), one of the collected ascidians showed peculiar perforations on its tunic. Once dissected, the perforations revealed to be the openings of a network of galleries excavated in the inner tunic (atrium) by at least six individuals of a polychaetous annelid. The worms belonged to the Autolytinae (Syllidae), a subfamily that is well known to include specialized predators and/or symbionts, mostly associated with cnidarians. The Red Sea worms are here described as Proceraea exoryxae sp. nov., which are anatomically distinguished by the combination of simple chaetae only in anterior chaetigers, and a unique trepan with 33 teeth in one outer ring where one large tooth alternates with one medium-sized tricuspid tooth, and one inner ring with small teeth located just behind the large teeth. Male and female epitokes were found together with atokous individuals within galleries. Proceraea exoryxae sp. nov. constitutes the first known miner in the Autolytinae and the second species in this taxon known to live symbiotically with ascidians. The implications of finding this specialized parasite are discussed considering that Phallusia nigra has been introduced worldwide, in tropical and sub-tropical ecosystems, where it has the potential of becoming invasive. PMID:28584710

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 Protection of Environment... SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.30 Applicability; description of the uranium, radium and vanadium ores subcategory. The provisions of this subpart C are applicable to...

Hydrogen Production by Steam Reforming of Natural Gas Over Vanadium-Nickel-Alumina Catalysts.

PubMed

Yoo, Jaekyeong; Park, Seungwon; Song, Ji Hwan; Song, In Kyu

2018-09-01

A series of vanadium-nickel-alumina (xVNA) catalysts were prepared by a single-step sol-gel method with a variation of vanadium content (x, wt%) for use in the hydrogen production by steam reforming of natural gas. The effect of vanadium content on the physicochemical properties and catalytic activities of xVNA catalysts in the steam reforming of natural gas was investigated. It was found that natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to vanadium content. It was also revealed that natural gas conversion and hydrogen yield increased with decreasing nickel crystallite size.

Effect of vanadium contamination on the framework and micropore structure of ultra stable Y-zeolite.

PubMed

Etim, U J; Xu, B; Ullah, Rooh; Yan, Z

2016-02-01

Y-zeolites are the main component of fluid catalytic cracking (FCC) catalyst for conversion of crude petroleum to products of high demand including transportation fuel. We investigated effects of vanadium which is present as one of the impurities in FCC feedstock on the framework and micropore structure of ultra-stable (US) Y-zeolite. The zeolite samples were prepared and characterized using standard techniques including: (1) X-ray diffraction, (2) N2 adsorption employing non local density functional theory method, NLDFT, (3) Transmittance and Pyridine FTIR, (4) Transmittance electron microscopy (TEM), and (5) (27)Al and (29)Si MAS-NMR. Results revealed that in the presence of steam, vanadium caused excessive evolution of non inter-crystalline mesopores and structural damage. The evolved mesopore size averaged about 25.0nm at 0.5wt.% vanadium loading, far larger than mesopore size in zeolitic materials with improved hydrothermal stability and performance for FCC catalyst. A mechanism of mesopore formation based on accelerated dealumination has been proposed and discussed. Vanadium immobilization experiments conducted to mitigate vanadium migration into the framework clearly showed vanadium is mobile at reaction conditions. From the results, interaction of vanadium with the passivator limits and decreases mobility and activity of vanadium into inner cavities of the zeolite capable of causing huge structure breakdown and acid sites destruction. This study therefore deepens insight into the causes of alteration in activity and selectivity of vanadium contaminated catalyst and hints on a possible mechanism of passivation in vanadium passivated FCC catalyst. Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis, Characterization, Antioxidant Status, and Toxicity Study of Vanadium-Rutin Complex in Balb/c Mice.

PubMed

Roy, Souvik; Majumdar, Sumana; Singh, Amit Kumar; Ghosh, Balaram; Ghosh, Nilanjan; Manna, Subhadip; Chakraborty, Tania; Mallick, Sougato

2015-08-01

A new trend was developed for the formation of a complex between vanadium and flavonoid derivatives in order to increase the intestinal absorption and to reduce the toxicity of vanadium compounds. The vanadium-rutin complex was characterized by several spectroscopic techniques like ultraviolet (UV)-visible, Fourier transform infrared (FTIR), NMR, mass spectrometry, and microscopic evaluation by scanning electron microscopy. The mononuclear complex was formed by the interaction between vanadium and rutin with 1:2 metal to ligand stoichiometry. Antioxidant activity of the complex was evaluated by 1,1-diphenyl-2 picrylhydrazyl, ferric-reducing power, and 2,2'-azin-obis 3-ethylbenzothiazoline-6-sulphonic acid methods. It was shown that radical scavenging activity and ferric-reducing potential of free rutin was lower as compared with vanadium-rutin complex. The study was also investigated for oral acute toxicity and 28 days repeated oral subacute toxicity study of vanadium-rutin complex in balb/c mice. The vanadium-rutin complex showed mortality at a dose of 120 mg/kg in the balb/c mice. In 28 days repeated oral toxicity study, vanadium-rutin complex was administered to both sex of balb/c mice at dose levels of 90, 45, and 20 ppm, respectively. In addition, subacute toxicity study of vanadium-rutin complex (at 90 ppm dose level) showed increase levels of white blood cell (WBC), total bilirubin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), creatinine, and blood urea nitrogen and decrease level of total protein (TP) as compared with control group. Histopathological study of vanadium-rutin showed structural alteration in the liver, kidney, and stomach at 90 ppm dose level. No observed toxic level of vanadium-rutin complex at 20 ppm dose level could be good for further study.

Directed synthesis of bio-inorganic vanadium oxide composites using genetically modified filamentous phage

NASA Astrophysics Data System (ADS)

Mueller, Michael; Baik, Seungyun; Jeon, Hojeong; Kim, Yuchan; Kim, Jungtae; Kim, Young Jun

2015-05-01

The growth of crystalline vanadium oxide using a filamentous bacteriophage template was investigated using sequential incubation in a V2O5 precursor. Using the genetic modification of the bacteriophage, we displayed two cysteines that constrained the RSTB-1 peptide on the major coat protein P8, resulting in vanadium oxide crystallization. The phage-driven vanadium oxide crystals with different topologies, microstructures, photodegradation and vanadium oxide composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz microbalance and dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). Non-specific electrostatic attraction between a wild-type phage (wt-phage) and vanadium cations in the V2O5 precursor caused phage agglomeration and fiber formation along the length of the viral scaffold. As a result, the addition of recombinant phage (re-phage) in V2O5 precursors formed heterogeneous structures, which led to efficient condensation of vanadium oxide crystal formation in lines, shown by QCM-D analysis. Furthermore, re-phage/VxOx composites showed significantly enhanced photodegradation activities compared with the synthesized wt-phage-V2O5 composite under illumination. This study demonstrates that peptide-mediated vanadium oxide mineralization is governed by a complicated interplay of peptide sequence, local structure, kinetics and the presence of a mineralizing aid, such as the two cysteine-constrained peptides on the phage surface, and has potential for use in nanotechnology applications.

Release from meiotic arrest in ascidian eggs requires the activity of two phosphatases but not CaMKII

PubMed Central

Levasseur, Mark; Dumollard, Remi; Chambon, Jean-Philippe; Hebras, Celine; Sinclair, Maureen; Whitaker, Michael; McDougall, Alex

2013-01-01

The fertilising sperm triggers a transient Ca2+ increase that releases eggs from cell cycle arrest in the vast majority of animal eggs. In vertebrate eggs, Erp1, an APC/Ccdc20 inhibitor, links release from metaphase II arrest with the Ca2+ transient and its degradation is triggered by the Ca2+-induced activation of CaMKII. By contrast, many invertebrate groups have mature eggs that arrest at metaphase I, and these species do not possess the CaMKII target Erp1 in their genomes. As a consequence, it is unknown exactly how cell cycle arrest at metaphase I is achieved and how the fertilisation Ca2+ transient overcomes the arrest in the vast majority of animal species. Using live-cell imaging with a novel cyclin reporter to study cell cycle arrest and its release in urochordate ascidians, the closest living invertebrate group to the vertebrates, we have identified a new signalling pathway for cell cycle resumption in which CaMKII plays no part. Instead, we find that the Ca2+-activated phosphatase calcineurin (CN) is required for egg activation. Moreover, we demonstrate that parthenogenetic activation of metaphase I-arrested eggs by MEK inhibition, independent of a Ca2+ increase, requires the activity of a second egg phosphatase: PP2A. Furthermore, PP2A activity, together with CN, is required for normal egg activation during fertilisation. As ascidians are a sister group of the vertebrates, we discuss these findings in relation to cell cycle arrest and egg activation in chordates. PMID:24194472

Amphiphilic block copolymer membrane for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Wang, Fei; Sylvia, James M.; Jacob, Monsy M.; Peramunage, Dharmasena

2013-11-01

An amphiphilic block copolymer comprised of hydrophobic polyaryletherketone (PAEK) and hydrophilic sulfonated polyaryletherketone (SPAEK) blocks has been synthesized and characterized. A membrane prepared from the block copolymer is used as the separator in a single cell vanadium redox flow battery (VRB). The proton conductivity, mechanical property, VO2+ permeability and single VRB cell performance of this block copolymer membrane are investigated and compared to Nafion™ 117. The block copolymer membrane showed significantly improved vanadium ion selectivity, higher mechanical strength and lower conductivity than Nafion™ 117. The VRB containing the block copolymer membrane exhibits higher coulombic efficiency and similar energy efficiency compared to a VRB using Nafion™ 117. The better vanadium ion selectivity of the block copolymer membrane has led to a much smaller capacity loss during 50 charge-discharge cycles for the VRB.

Insulating phases of vanadium dioxide are Mott-Hubbard insulators

DOE PAGES

Huffman, T. J.; Hendriks, C.; Walter, E. J.; ...

2017-02-15

Here, we present comprehensive broadband optical spectroscopy data on two insulating phases of vanadium dioxide (VO 2): monoclinic M 2 and triclinic. The main result of our work is that the energy gap and the electronic structure are essentially unaltered by the first-order structural phase transition between the M 2 and triclinic phases. Moreover, the optical interband features in the M 2 and triclinic phases are remarkably similar to those observed in the well-studied monoclinic M 1 insulating phase of VO 2. As the energy gap is insensitive to the different lattice structures of the three insulating phases, we rulemore » out vanadium-vanadium pairing (the Peierls component) as the dominant contributor to the opening of the gap. Rather, the energy gap arises primarily from intra-atomic Coulomb correlations.« less

The Influence of Vanadium on Ferrite and Bainite Formation in a Medium Carbon Steel

NASA Astrophysics Data System (ADS)

Sourmail, T.; Garcia-Mateo, C.; Caballero, F. G.; Cazottes, S.; Epicier, T.; Danoix, F.; Milbourn, D.

2017-09-01

The influence of vanadium additions on transformation kinetics has been investigated in a medium carbon forging steel. Using dilatometry to track transformation during continuous cooling or isothermal transformation, the impact of vanadium on both ferrite-pearlite and bainite has been quantified. Transmission electron microscopy and atom probe tomography have been used to establish whether vanadium was present in solid solution, or as clusters and precipitates. The results show that vanadium in solid solution has a pronounced retarding influence on ferrite-pearlite formation and that, unlike in the case of niobium, this effect can be exploited even during relatively slow cooling. The influence on bainite transformation was found to depend on temperature; an explanation in terms of the effect of vanadium on heterogeneous nucleation is tentatively proposed.

A comparative assessment of the acute inhalation toxicity of vanadium compounds.

PubMed

Rajendran, N; Seagrave, J C; Plunkett, L M; MacGregor, J A

2016-11-01

Vanadium compounds have become important in industrial processes, resulting in workplace exposure potential and are present in ambient air as a result of fossil fuel combustion. A series of acute nose-only inhalation toxicity studies was conducted in both rats and mice in order to obtain comparative data on the acute toxicity potential of compounds used commercially. V 2 O 3 , V 2 O 4 , and V 2 O 5 , which have different oxidation states (+3, +4, +5, respectively), were delivered as micronized powders; the highly water-soluble and hygroscopic VOSO 4 (+4) could not be micronized and was instead delivered as a liquid aerosol from an aqueous solution. V 2 O 5 was the most acutely toxic micronized powder in both species. Despite its lower overall percentage vanadium content, a liquid aerosol of VOSO 4 was more toxic than the V 2 O 5 particles in mice, but not in rats. These data suggest that an interaction of characteristics, i.e., bioavailability, solubility and oxidation state, as well as species sensitivity, likely affect the toxicity potential of vanadium compounds. Based on clinical observations and gross necropsy findings, the lung appeared to be the target organ for all compounds. The level of hazard posed will depend on the specific chemical form of the vanadium. Future work to define the inhalation toxicity potential of vanadium compounds of various oxidation states after repeated exposures will be important in understanding how the physico-chemical and biological characteristics of specific vanadium compounds interact to affect toxicity potential and the potential risks posed to human health.

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the...

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the...

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the...

Spectrophotometric determination of vanadium and its application to gas-turbine fuel-oils.

PubMed

Banerjee, S; Sinha, B P; Dutta, R K

1975-08-01

A very sensitive spectrophotometric method for the determination of vanadium in furnace oils is described. The intense indigo-blue colour developed by the reaction of vanadium with tannin and thioglycollic acid is measured at a wavelength of 600 nm at pH 4 and obeys Beer's law between 0.5 and 5 ppm vanadium. The method is applicable to gas-turbine fuel-oil and special navy fuel-oils. The common mineral constituents usually present in such oils do not interfere.

[Interaction Between Occupational Vanadium Exposure and hsp70-hom on Neurobehavioral Function].

PubMed

Zhang, Qin; Liu, Yun-xing; Cui, Li; Li, Shun-pin; Gao, Wei; Hu, Gao-lin; Zhang, Zu-hui; Lan, Ya-jia

2016-01-01

In determine the effect of heat shock protein 70-hom gene (hsp70-hom) polymorphism on the neurobehavioral function of workers exposed to vanadium. Workers from the vanadium products and chemical industry were recruited by cluster sampling. Demographic data and exposure information were collected using a questionnaire. Neurobehavioral function was assessed by Neurobehavioral Core Test Battery. The hsp70-hom genotype was detected by restricted fragment length polymorphism-polymerase chain reaction (RFLP-PCR). A neurobehavioral index (NBI) was formulated through principal component analysis. Workers with a T/C genotype had worse performance in average reaction time, visual retention, digital span (backward), Santa Ana aiming (non-habitual hand), pursuit aiming (right points, total points), digit symbol and NBI score than others (P < 0.05). The relative risk of abnormal NBI score of the workers with a T/C genotype was 1.748 fold of those with a T/T genotype. The relative risk of abnormal.NBI score of the workers exposed to vanadium was 3.048 fold of controls (P < 0.05). But after adjustment with age and education, only vanadium exposure appeared with a significant effect on NBI score. When gene polymorphism and vanadium exposure coexisted, the effect of vanadium on neurobehavioral function was attenuated, but the influence of T/C genotype increased Codds ratio (OR = 4.577, P < 0.05). After adjustment with age and education, the OR of T/C genotype further increased to 7.777 (P < 0.05). Vanadium exposure and T/C genotype had.a bio-interaction effect on NBI score Crelative excess risk due to interaction (RERI) = 4.12, attributable proportion (AP) = 0.7, synergy index (S) = 6.45]. After adjustment with age and education, the RERI became 2.49 and the AP became 0.75, but no coefficient of interaction was produced. Priorities of occupational protection should be given to vanadium-exposed workers with a hsp70-hom T/C genotype and low education level.

The presence of vanadium in groundwater of southeastern extreme the pampean region Argentina Relationship with other chemical elements.

PubMed

Fiorentino, Carmen E; Paoloni, Juan D; Sequeira, Mario E; Arosteguy, Pedro

2007-08-15

Changes in the quality of groundwater resources are related to the presence and concentration of contaminants, especially trace elements such as arsenic, boron, fluoride and vanadium. Vanadium is a rare element naturally abundant, generally found in combination with other elements. Vanadium pentoxide is known to have aneugenic effects. Thus, a study was carried out to assess the presence of vanadium in the groundwater of the southeastern pampean region of Argentina, which constitutes the main water supply for the local population. Statistical and correlational analyses were applied to identify possible interrelationships between vanadium and another chemical elements. Vanadium was found in all groundwater samples. The minimum and maximum vanadium concentrations found were 0.05 mg/l and 2.47 mg/l, respectively. Vanadium is significantly correlated with other trace elements such as arsenic, fluoride and boron. The interrelationship between vanadium and the presence of volcanic glass in sediments is not significant as expected.

Titanium, vanadium, and niobium mineralization and alkali metasomatism from the Magnet Cove complex, Arkansas

USGS Publications Warehouse

Flohr, M.J.K.

1994-01-01

The Christy deposit formed through a series of complex processes. The initial phase of mineralization is directly related to the infiltration of novaculite by alkali-rich fluids that were probably derived from carbonatite magma. Titanium, V, Nb, and Li were introduced by the alkali-rich fluids at temperatures that were as high as 600??C. During the initial stage of mineralization, V was concentrated in aegirine and sodic amphibole, Li was concentrated in taeniolite, minor amounts of Ti were concentrated in aegirine, and pyrite formed. The replacement of novaculite by the aforementioned minerals yielded excess silica, which precipitated as quartz. Niobium- and V-bearing brookite precipitated with the quartz. Minerals formed during the first stage reacted with a second fluid at temperatures of 100?? to 300??C and V was then concentrated in smectite and goethite. The second fluid was a mixture of low-temperature metasomatic fluid and groundwater. Vanadium was further concentrated in clay minerals in goethite, and in vug minerals as low-temperature alteration proceeded. -from Author

Investigation on the fates of vanadium and nickel during co-gasification of petroleum coke with biomass.

PubMed

Li, Jiazhou; Wang, Xiaoyu; Wang, Bing; Zhao, Jiantao; Fang, Yitian

2018-06-01

This study investigates the volatilization behaviors and mineral transformation of vanadium and nickel during co-gasification of petroleum coke with biomass. Moreover, the evolution of occurrence modes of vanadium and nickel was also determined by the method of sequential chemical extraction. The results show that the volatilities of vanadium and nickel in petroleum coke have a certain level of growth with an increase in the temperature. With the addition of biomass, their volatilities both show an obvious decrease. Organic matter and stable forms are the dominant chemical forms of vanadium and nickel. After gasification, organic-bound vanadium and nickel decompose completely and convert into other chemical forms. The crystalline phases of vanadium trioxide, coulsonite, nickel sulfide, and elemental nickel are clearly present in petroleum coke and biomass gasification ashes. When the addition of biomass reaches 60 wt%, the diffraction peaks of orthovanadate are found while that of vanadium trioxide disappear. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hydrophilic Channel Alignment of Perfluoronated Sulfonic-Acid Ionomers for Vanadium Redox Flow Batteries.

PubMed

So, Soonyong; Cha, Min Suc; Jo, Sang-Woo; Kim, Tae-Ho; Lee, Jang Yong; Hong, Young Taik

2018-06-13

It is known that uniaxially drawn perfluoronated sulfonic-acid ionomers (PFSAs) show diffusion anisotropy because of the aligned water channels along the deformation direction. We apply the uniaxially stretched membranes to vanadium redox flow batteries (VRFBs) to suppress the permeation of active species, vanadium ions through the transverse directions. The aligned water channels render much lower vanadium permeability, resulting in higher Coulombic efficiency (>98%) and longer self-discharge time (>250 h). Similar to vanadium ions, proton conduction through the membranes also decreases as the stretching ratio increases, but the thinned membranes show the enhanced voltage and energy efficiencies over the range of current density, 50-100 mA/cm 2 . Hydrophilic channel alignment of PFSAs is also beneficial for long-term cycling of VRFBs in terms of capacity retention and cell performances. This simple pretreatment of membranes offers an effective and facile way to overcome high vanadium permeability of PFSAs for VRFBs.

Cellular uptake of titanium and vanadium from addition of salts or fretting corrosion in vitro

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

Maurer, A.M.; Merritt, K.; Brown, S.A.

1994-02-01

The use of titanium and titanium-6% aluminum-4% vanadium alloy for dental and orthopedic implants has increased in the last decade. The implants are presumed to be compatible because oseointegration, bony apposition, and cell attachment are known. However, the cellular association of titanium and vanadium have remained unknown. This study examined the uptake of salts or fretting corrosion products. Titanium was not observed to be toxic to the cells. Vanadium was toxic at levels greater than 10[mu]g/mL. The percentage of cellular association of titanium was shown to be about 10 times that of vanadium. The percentage of cellular association of eithermore » element was greater from fretting corrosion than from the addition of salts. The presence of vanadium did not affect the cellular uptake of titanium. The presence of titanium decreased the cell association of vanadium.« less

Protective effects of Sesamum indicum extract against oxidative stress induced by vanadium on isolated rat hepatocytes.

PubMed

Hosseini, Mir-Jamal; Shahraki, Jafar; Tafreshian, Saman; Salimi, Ahmad; Kamalinejad, Mohammad; Pourahmad, Jalal

2016-08-01

Vanadium toxicity is a challenging problem to human and animal health with no entirely understanding cytotoxic mechanisms. Previous studies in vanadium toxicity showed involvement of oxidative stress in isolated liver hepatocytes and mitochondria via increasing of ROS formation, release of cytochrome c and ATP depletion after incubation with different concentrations (25-200 µM). Therefore, we aimed to investigate the protective effects of Sesamum indicum seed extract (100-300 μg/mL) against oxidative stress induced by vanadium on isolated rat hepatocytes. Our results showed that quite similar to Alpha-tocopherol (100 µM), different concentrations of extract (100-300 μg/mL) protected the isolated hepatocyte against all oxidative stress/cytotoxicity markers induced by vanadium in including cell lysis, ROS generation, mitochondrial membrane potential decrease and lysosomal membrane damage. Besides, vanadium induced mitochondrial/lysosomal toxic interaction and vanadium reductive activation mediated by glutathione in vanadium toxicity was significantly (P < 0.05) ameliorated by Sesamum indicum extracts. These findings suggested a hepato-protective role for extracts against liver injury resulted from vanadium toxicity. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 979-985, 2016. © 2015 Wiley Periodicals, Inc.

76 FR 78888 - Final Results of Expedited Sunset Review: Ferrovanadium and Nitrided Vanadium From Russia

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-20

... Sunset Review: Ferrovanadium and Nitrided Vanadium From Russia AGENCY: Import Administration... and nitrided vanadium from the Russian Federation (Russia), pursuant to section 751(c) of the Tariff... vanadium from Russia, pursuant to section 751(c) of the Act. See Initiation of Five-Year (``Sunset...

Current status and associated human health risk of vanadium in soil in China.

PubMed

Yang, Jie; Teng, Yanguo; Wu, Jin; Chen, Haiyang; Wang, Guoqiang; Song, Liuting; Yue, Weifeng; Zuo, Rui; Zhai, Yuanzheng

2017-03-01

A detailed assessment of vanadium contamination characteristics in China was conducted based on the first national soil pollution survey. The map overlay analysis was used to evaluate the contamination level of vanadium and the non-carcinogenic risk assessment model was calculated to quantify the vanadium exposure risks to human health. The results showed that, due to the drastically increased mining and smelting activities, 26.49% of soils were contaminated by vanadium scattered in southwest of China. According to Canadian soil quality guidelines, about 8.6% of the national soil pollution survey samples were polluted, and pose high non-carcinogenic risks to the public, especially to children living in the vicinity of heavily polluted mining areas. We propose the area near the boundary of Yunnan, Guizhou, Guangxi, and Sichuan provinces as priority control areas due to their higher geochemical background or higher health risks posed to the public. Finally, recommendations for management are proposed, including minimization of contaminant inputs, establishing stringent monitoring program, using phytoremediation, and strengthening the enforcement of relevant laws. Therefore, this study provides a comprehensive assessment of soil vanadium contamination in China, and the results will provide valuable information for China's soil vanadium management and risk avoidance. Copyright © 2016 Elsevier Ltd. All rights reserved.

The determination of vanadium in brines by atomic absorption spectroscopy

USGS Publications Warehouse

Crump-Wiesner, Hans J.; Feltz, H.R.; Purdy, W.C.

1971-01-01

A standard addition method is described for the determination of vanadium in brines by atomic absorption spectroscopy with a nitrous oxide-acetylene flame. Sample pH is adjusted to 1.0 with concentrated hydrochloric acid and the vanadium is directly extracted with 5% cupferron in methyl isobutyl ketone (MIBK). The ketone layer is then aspirated into the flame and the recorded absorption values are plotted as a function of the concentration of the added metal. As little as 2.5 ??g l-1 of vanadium can be detected under the conditions of the procedure. Tungsten and tin interfere when present in excess of 5 and 10 ??g ml-1, respectively. The concentrations of the two interfering ions normally found in brines are well below interference levels. ?? 1971.

Ultrastructures and classification of circulating hemocytes in 9 botryllid ascidians (chordata: ascidiacea).

PubMed

Hirose, Euichi; Shirae, Maki; Saito, Yasunori

2003-05-01

Ultrastructures of circulating hemocytes were studied in 9 botryllid ascidians. The hemocytes are classified into five types: hemoblasts, phagocytes, granulocytes, morula cells, and pigment cells. These five types are always found in the 9 species. They should represent the major hemocyte types of the circulating cells in the blood. Hemoblasts are small hemocytes having a high nucleus/cytoplasm ratio. There are few granular or vacuolar inclusions in the cytoplasm. Phagocytes have phagocytic activity and their shape is variable depending on the amount of engulfed materials. In granulocytes, shape and size of granules are different among the species. Morula cells are characterized by several vacuoles filled with electron dense materials. In pigment cells, the bulk of the cytoplasm is occupied by one or a few vacuoles containing pigment granules. We also described some other hemocyte types found in particular species. Furthermore, we encountered free oocytes circulating in the blood in two species, Botryllus primigenus and Botrylloides lentus.

77 FR 54897 - Ferrovanadium and Nitrided Vanadium from the Russian Federation: Revocation of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-06

... nitrided vanadium from the Russian Federation (Russia) would not be likely to lead to continuation or... the antidumping duty order on ferrovanadium and nitrided vanadium from Russia. \\1\\ See Ferrovanadium and Nitrided Vanadium From Russia, 77 FR 51825 (August 27, 2012) (ITC Final). DATES: Effective Date...

Growth control of the oxidation state in vanadium oxide thin films

DOE PAGES

Lee, Shinbuhm; Meyer, Tricia L.; Park, Sungkyun; ...

2014-12-05

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research, but also technological applications that utilize the subtle change in the physical properties originating from the metalinsulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase puremore » epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V₂⁺²O₃, V⁺⁴O₂, and V₂⁺⁵O₅. A well pronounced MIT was only observed in VO₂ films grown in a very narrow range of oxygen partial pressure P(O₂). The films grown either in lower (< 10 mTorr) or higher P(O₂) (> 25 mTorr) result in V₂O₃ and V₂O₅ phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO₂ thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an 3 improved MIT behavior.« less

Growth control of the oxidation state in vanadium oxide thin films

NASA Astrophysics Data System (ADS)

Lee, Shinbuhm; Meyer, Tricia L.; Park, Sungkyun; Egami, Takeshi; Lee, Ho Nyung

2014-12-01

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research but also technological applications that utilize the subtle change in the physical properties originating from the metal-insulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase pure epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V2 + 3 O 3 , V + 4 O 2 , and V2 + 5 O 5 . A well pronounced MIT was only observed in VO2 films grown in a very narrow range of oxygen partial pressure P(O2). The films grown either in lower (<10 mTorr) or higher P(O2) (>25 mTorr) result in V2O3 and V2O5 phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO2 thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an improved MIT behavior.

Genetic signatures of natural selection in a model invasive ascidian

NASA Astrophysics Data System (ADS)

Lin, Yaping; Chen, Yiyong; Yi, Changho; Fong, Jonathan J.; Kim, Won; Rius, Marc; Zhan, Aibin

2017-03-01

Invasive species represent promising models to study species’ responses to rapidly changing environments. Although local adaptation frequently occurs during contemporary range expansion, the associated genetic signatures at both population and genomic levels remain largely unknown. Here, we use genome-wide gene-associated microsatellites to investigate genetic signatures of natural selection in a model invasive ascidian, Ciona robusta. Population genetic analyses of 150 individuals sampled in Korea, New Zealand, South Africa and Spain showed significant genetic differentiation among populations. Based on outlier tests, we found high incidence of signatures of directional selection at 19 loci. Hitchhiking mapping analyses identified 12 directional selective sweep regions, and all selective sweep windows on chromosomes were narrow (~8.9 kb). Further analyses indentified 132 candidate genes under selection. When we compared our genetic data and six crucial environmental variables, 16 putatively selected loci showed significant correlation with these environmental variables. This suggests that the local environmental conditions have left significant signatures of selection at both population and genomic levels. Finally, we identified “plastic” genomic regions and genes that are promising regions to investigate evolutionary responses to rapid environmental change in C. robusta.

Genetic signatures of natural selection in a model invasive ascidian

PubMed Central

Lin, Yaping; Chen, Yiyong; Yi, Changho; Fong, Jonathan J.; Kim, Won; Rius, Marc; Zhan, Aibin

2017-01-01

Invasive species represent promising models to study species’ responses to rapidly changing environments. Although local adaptation frequently occurs during contemporary range expansion, the associated genetic signatures at both population and genomic levels remain largely unknown. Here, we use genome-wide gene-associated microsatellites to investigate genetic signatures of natural selection in a model invasive ascidian, Ciona robusta. Population genetic analyses of 150 individuals sampled in Korea, New Zealand, South Africa and Spain showed significant genetic differentiation among populations. Based on outlier tests, we found high incidence of signatures of directional selection at 19 loci. Hitchhiking mapping analyses identified 12 directional selective sweep regions, and all selective sweep windows on chromosomes were narrow (~8.9 kb). Further analyses indentified 132 candidate genes under selection. When we compared our genetic data and six crucial environmental variables, 16 putatively selected loci showed significant correlation with these environmental variables. This suggests that the local environmental conditions have left significant signatures of selection at both population and genomic levels. Finally, we identified “plastic” genomic regions and genes that are promising regions to investigate evolutionary responses to rapid environmental change in C. robusta. PMID:28266616

Why Antidiabetic Vanadium Complexes are Not in the Pipeline of "Big Pharma" Drug Research? A Critical Review.

PubMed

Scior, Thomas; Guevara-Garcia, Jose Antonio; Do, Quoc-Tuan; Bernard, Philippe; Laufer, Stefan

2016-01-01

Public academic research sites, private institutions as well as small companies have made substantial contributions to the ongoing development of antidiabetic vanadium compounds. But why is this endeavor not echoed by the globally operating pharmaceutical companies, also known as "Big Pharma"? Intriguingly, today's clinical practice is in great need to improve or replace insulin treatment against Diabetes Mellitus (DM). Insulin is the mainstay therapeutically and economically. So, why do those companies develop potential antidiabetic drug candidates without vanadium (vanadium- free)? We gathered information about physicochemical and pharmacological properties of known vanadium-containing antidiabetic compounds from the specialized literature, and converted the data into explanations (arguments, the "pros and cons") about the underpinnings of antidiabetic vanadium. Some discoveries were embedded in chronological order while seminal reviews of the last decade about the Medicinal chemistry of vanadium and its history were also listed for further understanding. In particular, the concepts of so-called "noncomplexed or free" vanadium species (i.e. inorganic oxido-coordinated species) and "biogenic speciation" of antidiabetic vanadium complexes were found critical and subsequently documented in more details to answer the question.

Physiological and anthocyanin biosynthesis genes response induced by vanadium stress in mustard genotypes with distinct photosynthetic activity.

PubMed

Imtiaz, Muhammad; Mushtaq, Muhammad Adnan; Nawaz, Muhammad Amjad; Ashraf, Muhammad; Rizwan, Muhammad Shahid; Mehmood, Sajid; Aziz, Omar; Rizwan, Muhammad; Virk, Muhammad Safiullah; Shakeel, Qaiser; Ijaz, Raina; Androutsopoulos, Vasilis P; Tsatsakis, Aristides M; Coleman, Michael D

2018-06-13

The present study aimed to elucidate the photosynthetic performance, antioxidant enzyme activities, anthocyanin contents, anthocyanin biosynthetic gene expression, and vanadium uptake in mustard genotypes (purple and green) that differ in photosynthetic capacity under vanadium stress. The results indicated that vanadium significantly reduced photosynthetic activity in both genotypes. The activities of the antioxidant enzymes were increased significantly in response to vanadium in both genotypes, although the purple exhibited higher. The anthocyanin contents were also reduced under vanadium stress. The anthocyanin biosynthetic genes were highly expressed in the purple genotype, notably the genes TT8, F3H, and MYBL2 under vanadium stress. The results indicate that induction of TT8, F3H, and MYBL2 genes was associated with upregulation of the biosynthetic genes required for higher anthocyanin biosynthesis in purple compared with the green mustard. The roots accumulated higher vanadium than shoots in both mustard genotypes. The results indicate that the purple mustard had higher vanadium tolerance. Copyright © 2018 Elsevier B.V. All rights reserved.

Vanadium based materials as electrode materials for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Yan, Yan; Li, Bing; Guo, Wei; Pang, Huan; Xue, Huaiguo

2016-10-01

As a kind of supercapacitors, pseudocapacitors have attracted wide attention in recent years. The capacitance of the electrochemical capacitors based on pseudocapacitance arises mainly from redox reactions between electrolytes and active materials. These materials usually have several oxidation states for oxidation and reduction. Many research teams have focused on the development of an alternative material for electrochemical capacitors. Many transition metal oxides have been shown to be suitable as electrode materials of electrochemical capacitors. Among them, vanadium based materials are being developed for this purpose. Vanadium based materials are known as one of the best active materials for high power/energy density electrochemical capacitors due to its outstanding specific capacitance and long cycle life, high conductivity and good electrochemical reversibility. There are different kinds of synthetic methods such as sol-gel hydrothermal/solvothermal method, template method, electrospinning method, atomic layer deposition, and electrodeposition method that have been successfully applied to prepare vanadium based electrode materials. In our review, we give an overall summary and evaluation of the recent progress in the research of vanadium based materials for electrochemical capacitors that include synthesis methods, the electrochemical performances of the electrode materials and the devices.

Novel hybrid materials based on the vanadium oxide nanobelts

NASA Astrophysics Data System (ADS)

Zabrodina, G. S.; Makarov, S. G.; Kremlev, K. V.; Yunin, P. A.; Gusev, S. A.; Kaverin, B. S.; Kaverina, L. B.; Ketkov, S. Yu.

2016-04-01

Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V2O5·nH2O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB - cetyltrimethylammonium bromide, TBAB - tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA)0.33V2O5 flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA)0.33V2O5, (TBA)0.16V2O5 nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

Direct activation of a notochord cis-regulatory module by Brachyury and FoxA in the ascidian Ciona intestinalis.

PubMed

Passamaneck, Yale J; Katikala, Lavanya; Perrone, Lorena; Dunn, Matthew P; Oda-Ishii, Izumi; Di Gregorio, Anna

2009-11-01

The notochord is a defining feature of the chordate body plan. Experiments in ascidian, frog and mouse embryos have shown that co-expression of Brachyury and FoxA class transcription factors is required for notochord development. However, studies on the cis-regulatory sequences mediating the synergistic effects of these transcription factors are complicated by the limited knowledge of notochord genes and cis-regulatory modules (CRMs) that are directly targeted by both. We have identified an easily testable model for such investigations in a 155-bp notochord-specific CRM from the ascidian Ciona intestinalis. This CRM contains functional binding sites for both Ciona Brachyury (Ci-Bra) and FoxA (Ci-FoxA-a). By combining point mutation analysis and misexpression experiments, we demonstrate that binding of both transcription factors to this CRM is necessary and sufficient to activate transcription. To gain insights into the cis-regulatory criteria controlling its activity, we investigated the organization of the transcription factor binding sites within the 155-bp CRM. The 155-bp sequence contains two Ci-Bra binding sites with identical core sequences but opposite orientations, only one of which is required for enhancer activity. Changes in both orientation and spacing of these sites substantially affect the activity of the CRM, as clusters of identical sites found in the Ciona genome with different arrangements are unable to activate transcription in notochord cells. This work presents the first evidence of a synergistic interaction between Brachyury and FoxA in the activation of an individual notochord CRM, and highlights the importance of transcription factor binding site arrangement for its function.

Brain Metal Distribution and Neuro-Inflammatory Profiles after Chronic Vanadium Administration and Withdrawal in Mice

PubMed Central

Folarin, Oluwabusayo R.; Snyder, Amanda M.; Peters, Douglas G.; Olopade, Funmilayo; Connor, James R.; Olopade, James O.

2017-01-01

Vanadium is a potentially toxic environmental pollutant and induces oxidative damage in biological systems including the central nervous system (CNS). Its deposition in brain tissue may be involved in the pathogenesis of certain neurological disorders which after prolonged exposure can culminate into more severe pathology. Most studies on vanadium neurotoxicity have been done after acute exposure but in reality some populations are exposed for a lifetime. This work was designed to ascertain neurodegenerative consequences of chronic vanadium administration and to investigate the progressive changes in the brain after withdrawal from vanadium treatment. A total of 85 male BALB/c mice were used for the experiment and divided into three major groups of vanadium treated (intraperitoneally (i.p.) injected with 3 mg/kg body weight of sodium metavanadate and sacrificed every 3 months till 18 months); matched controls; and animals that were exposed to vanadium for 3 months and thereafter the metal was withdrawn. Brain tissues were obtained after animal sacrifice. Sagittal cut sections of paraffin embedded tissue (5 μm) were analyzed by the Laser ablation-inductively coupled plasma-mass spectrometry (LA–ICP–MS) to show the absorption and distribution of vanadium metal. Also, Haematoxylin and Eosin (H&E) staining of brain sections, and immunohistochemistry for Microglia (Iba-1), Astrocytes (GFAP), Neurons (Neu-N) and Neu-N + 4′,6-diamidine-2′-pheynylindole dihydrochloride (Dapi) Immunofluorescent labeling were observed for morphological and morphometric parameters. The LA–ICP–MS results showed progressive increase in vanadium uptake with time in different brain regions with prediction for regions like the olfactory bulb, brain stem and cerebellum. The withdrawal brains still show presence of vanadium metal in the brain slightly more than the controls. There were morphological alterations (of the layering profile, nuclear shrinkage) in the prefrontal cortex

Ab initio Investigation of Helium in Vanadium Oxide Nanoclusters

NASA Astrophysics Data System (ADS)

Danielson, Thomas; Tea, Eric; Hin, Celine

Nanostructured ferritic alloys (NFAs) are strong candidate materials for the next generation of fission reactors and future fusion reactors. They are characterized by a large number density of oxide nanoclusters dispersed throughout a BCC iron matrix, where current oxide nanoclusters are primarily comprised of Y-Ti-O compounds. The oxide nanoclusters provide the alloy with high resistance to neutron irradiation, high yield strength and high creep strength at the elevated temperatures of a reactor environment. In addition, the oxide nanoclusters serve as trapping sites for transmutation product helium providing substantially increased resistance to catastrophic cracking and embrittlement. Although the mechanical properties and radiation resistance of the existing NFAs is promising, the problem of forming large scale reactor components continues to present a formidable challenge due to the high hardness and unpredictable fracture behavior of the alloys. An alternative alloy has been previously proposed and fabricated where vanadium is added in order to form vanadium oxide nanoclusters that serve as deflection sites for crack propagation. Although experiments have shown evidence that the fracture behavior of the alloys is improved, it is unknown whether or not the vanadium oxide nanoclusters are effective trapping sites for helium. We present results obtained using density functional theory investigating the thermodynamic stability of helium with the vanadium oxide matrix to make a comparison of trapping effectiveness to traditional Y-Ti-O compounds.

Modeling of ion transport through a porous separator in vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Zhou, X. L.; Zhao, T. S.; An, L.; Zeng, Y. K.; Wei, L.

2016-09-01

In this work, we develop a two-dimensional, transient model to investigate the mechanisms of ion-transport through a porous separator in VRFBs and their effects on battery performance. Commercial-available separators with pore sizes of around 45 nm are particularly investigated and effects of key separator design parameters and operation modes are explored. We reveal that: i) the transport mechanism of vanadium-ion crossover through available separators is predominated by convection; ii) reducing the pore size below 15 nm effectively minimizes the convection-driven vanadium-ion crossover, while further reduction in migration- and diffusion-driven vanadium-ion crossover can be achieved only when the pore size is reduced to the level close to the sizes of vanadium ions; and iii) operation modes that can affect the pressure at the separator/electrode interface, such as the electrolyte flow rate, exert a significant influence on the vanadium-ion crossover rate through the available separators, indicating that it is critically important to equalize the pressure on each half-cell of a power pack in practical applications.

Convergent Acquisition of Nonembryonic Development in Styelid Ascidians

PubMed Central

Alié, Alexandre; Hiebert, Laurel Sky; Simion, Paul; Scelzo, Marta; Prünster, Maria Mandela; Lotito, Sonia; Delsuc, Frédéric; Douzery, Emmanuel J P; Dantec, Christelle; Lemaire, Patrick; Darras, Sébastien; Kawamura, Kazuo; Brown, Federico D; Tiozzo, Stefano

2018-01-01

Abstract Asexual propagation and whole body regeneration are forms of nonembryonic development (NED) widespread across animal phyla and central in life history and evolutionary diversification of metazoans. Whereas it is challenging to reconstruct the gains or losses of NED at large phylogenetic scale, comparative studies could benefit from being conducted at more restricted taxonomic scale, in groups for which phylogenetic relationships are well established. The ascidian family of Styelidae encompasses strictly sexually reproducing solitary forms as well as colonial species that combine sexual reproduction with different forms of NED. To date, the phylogenetic relationships between colonial and solitary styelids remain controversial and so is the pattern of NED evolution. In this study, we built an original pipeline to combine eight genomes with 18 de novo assembled transcriptomes and constructed data sets of unambiguously orthologous genes. Using a phylogenomic super-matrix of 4,908 genes from these 26 tunicates we provided a robust phylogeny of this family of chordates, which supports two convergent acquisitions of NED. This result prompted us to further describe the budding process in the species Polyandrocarpa zorritensis, leading to the discovery of a novel mechanism of asexual development. Whereas the pipeline and the data sets produced can be used for further phylogenetic reconstructions in tunicates, the phylogeny provided here sets an evolutionary framework for future experimental studies on the emergence and disappearance of complex characters such as asexual propagation and whole body regeneration. PMID:29660002

Amorphous Mixed-Valence Vanadium Oxide/Exfoliated Carbon Cloth Structure Shows a Record High Cycling Stability.

PubMed

Song, Yu; Liu, Tian-Yu; Yao, Bin; Kou, Tian-Yi; Feng, Dong-Yang; Liu, Xiao-Xia; Li, Yat

2017-04-01

Previous studies show that vanadium oxides suffer from severe capacity loss during cycling in the liquid electrolyte, which has hindered their applications in electrochemical energy storage. The electrochemical instability is mainly due to chemical dissolution and structural pulverization of vanadium oxides during charge/discharge cyclings. In this study the authors demonstrate that amorphous mixed-valence vanadium oxide deposited on exfoliated carbon cloth (CC) can address these two limitations simultaneously. The results suggest that tuning the V 4+ /V 5+ ratio of vanadium oxide can efficiently suppress the dissolution of the active materials. The oxygen-functionalized carbon shell on exfoliated CC can bind strongly with VO x via the formation of COV bonding, which retains the electrode integrity and suppresses the structural degradation of the oxide during charging/discharging. The uptake of structural water during charging and discharging processes also plays an important role in activating the electrode material. The amorphous mixed-valence vanadium oxide without any protective coating exhibits record-high cycling stability in the aqueous electrolyte with no capacitive decay in 100 000 cycles. This work provides new insights on stabilizing vanadium oxide, which is critical for the development of vanadium oxide based energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complex formation of vanadium(V) with resorcylalhydrazides of carboxylic acids

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

Dudarev, V.I.; Dolgorev, V.A.; Volkov, A.N.

1986-08-01

In this work, a previous investigation of hydrazine derivatives as analytical reagents for vanadium(V) was continued. The authors studied arylalhydrazones -- derivatives of resorcylalhydrazides of anisic (RHASA), anthranilic (RHANA), and benzoic (RHBA) acids. The reagents presented differ from those studied previously by the presence of a second hydroxy group in the para-position of the benzene ring -the resorcinol fragment -- and substituents in the benzoin fragment. Such changes made it possible to increase the solubility of the reagents in aqueous medium and to estimate the change in the main spectrophotometric parameters of the analytical reaction. A rapid method was developedmore » for the determination of vanadium in steels with the resorcylalhydrazide of anthranilic acid. The minimum determinable vanadium content is 0.18 micrograms/ml.« less

Vanadium K-edge X-ray absorption spectroscopy of bromoperoxidase from Ascophyllum nodosum

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

Arber, J.M.; de Boer, E.; Garner, C.D.

Bromoperoxidase from Ascophyllum nodusum was the first vanadium-containing enzyme to be isolated. X-ray absorption spectra have now been collected in order to investigate the coordination of vanadium in the native, native plus bromide, native plus hydrogen peroxide, and dithionite-reduced forms of the enzyme. The edge and X-ray absorption near-edge structures show that, in the four samples studied, it is only on reduction of the native enzyme that the metal site is substantially altered. In addition, these data are consistent with the presence of vanadium(IV) in the reduced enzyme and vanadium(V) in the other samples. Extended X-ray absorption fine structure datamore » confirm that there are structural changes at the metal site on reduction of the native enzyme, notably a lengthening of the average inner-shell distance, and the presence of terminal oxygen together with histidine and oxygen-donating residues.« less

Investigation of crossover processes in a unitized bidirectional vanadium/air redox flow battery

NASA Astrophysics Data System (ADS)

grosse Austing, Jan; Nunes Kirchner, Carolina; Komsiyska, Lidiya; Wittstock, Gunther

2016-02-01

In this paper the losses in coulombic efficiency are investigated for a vanadium/air redox flow battery (VARFB) comprising a two-layered positive electrode. Ultraviolet/visible (UV/Vis) spectroscopy is used to monitor the concentrations cV2+ and cV3+ during operation. The most likely cause for the largest part of the coulombic losses is the permeation of oxygen from the positive to the negative electrode followed by an oxidation of V2+ to V3+. The total vanadium crossover is followed by inductively coupled plasma mass spectroscopy (ICP-MS) analysis of the positive electrolyte after one VARFB cycle. During one cycle 6% of the vanadium species initially present in the negative electrolyte are transferred to the positive electrolyte, which can account at most for 20% of the coulombic losses. The diffusion coefficients of V2+ and V3+ through Nafion® 117 are determined as DV2+ ,N 117 = 9.05 ·10-6 cm2 min-1 and DV3+ ,N 117 = 4.35 ·10-6 cm2 min-1 and are used to calculate vanadium crossover due to diffusion which allows differentiation between vanadium crossover due to diffusion and migration/electroosmotic convection. In order to optimize coulombic efficiency of VARFB, membranes need to be designed with reduced oxygen permeation and vanadium crossover.

Growth control of the oxidation state in vanadium oxide thin films

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

Lee, Shinbuhm; Meyer, Tricia L.; Lee, Ho Nyung, E-mail: hnlee@ornl.gov

2014-12-01

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research but also technological applications that utilize the subtle change in the physical properties originating from the metal-insulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase puremore » epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V{sub 2}{sup +3}O{sub 3}, V{sup +4}O{sub 2}, and V{sub 2}{sup +5}O{sub 5}. A well pronounced MIT was only observed in VO{sub 2} films grown in a very narrow range of oxygen partial pressure P(O{sub 2}). The films grown either in lower (<10 mTorr) or higher P(O{sub 2}) (>25 mTorr) result in V{sub 2}O{sub 3} and V{sub 2}O{sub 5} phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO{sub 2} thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an improved MIT behavior.« less

Vanadium(IV)-stimulated hydrolysis of 2,3-diphosphoglycerate.

PubMed

Stankiewicz, P J

1989-05-01

Vanadium(IV) stimulates the hydrolysis of 2,3-diphosphoglycerate at 23 degrees C. The pH optimum is 5.0. Reactions were analyzed by enzymatic and phosphate release assays. The products of 2,3-diphosphoglycerate hydrolysis are inorganic phosphate and 3-phosphoglycerate. The reaction is inhibited by high concentrations of 2,3-diphosphoglycerate and an equation has been formulated that describes the kinetic constants for this reaction at pH 7. The possible relevance of the reaction to the therapeutic lowering by vanadium(IV) of red cell 2,3-diphosphoglycerate in sickle-cell disease is discussed.

Insulin and vanadium protect against osteoarthritis development secondary to diabetes mellitus in rats.

PubMed

El Karib, Abbas O; Al-Ani, Bahjat; Al-Hashem, Fahaid; Dallak, Mohammad; Bin-Jaliah, Ismaeel; El-Gamal, Basiouny; Bashir, Salah O; Eid, Refaat A; Haidara, Mohamed A

2016-07-01

Diabetic complications such as cardiovascular disease and osteoarthritis (OA) are among the common public health problems. The effect of insulin on OA secondary to diabetes has not been investigated before in animal models. Therefore, we sought to determine whether insulin and the insulin-mimicking agent, vanadium can protect from developing OA in diabetic rats. Type 1 diabetes mellitus (T1DM) was induced in Sprague-Dawley rats and treated with insulin and/or vanadium. Tissues harvested from the articular cartilage of the knee joint were examined by scanning electron microscopy, and blood samples were assayed for oxidative stress and inflammatory biomarkers. Eight weeks following the induction of diabetes, a profound damage to the knee joint compared to the control non-diabetic group was observed. Treatment of diabetic rats with insulin and/or vanadium differentially protected from diabetes-induced cartilage damage and deteriorated fibrils of collagen fibers. The relative biological potencies were insulin + vanadium > insulin > vanadium. Furthermore, there was about 2- to 5-fold increase in TNF-α (from 31.02 ± 1.92 to 60.5 ± 1.18 pg/ml, p < 0.0001) and IL-6 (from 64.67 ± 8.16 to 338.0 ± 38.9 pg/ml, p < 0.0001) cytokines and free radicals measured as TBARS (from 3.21 ± 0.37 to 11.48 ± 1.5 µM, p < 0.0001) in the diabetic group, which was significantly reduced with insulin and or vanadium. Meanwhile, SOD decreased (from 17.79 ± 8.9 to 8.250.29, p < 0.0001) and was increased with insulin and vanadium. The relative potencies of the treating agents on inflammatory and oxidative stress biomarkers were insulin + vanadium > insulin > vanadium. The present study demonstrates that co-administration of insulin and vanadium to T1DM rats protect against diabetes-induced OA possibly by lowering biomarkers of inflammation and oxidative stress.

Unfolding a chordate developmental program, one cell at a time: invariant cell lineages, short-range inductions and evolutionary plasticity in ascidians.

PubMed

Lemaire, Patrick

2009-08-01

Ascidians were historically the first metazoans in which experimental embryology was carried out. These early works by Chabry and Conklin [Chabry, L., 1887. Embryologie normale et tératologique des Ascidie. Felix Alcan Editeur, Paris; Conklin, E., 1905. The organization and cell lineage of the ascidian egg. J. Acad., Nat. Sci. Phila. 13, 1], in particular, led to the idea that the developmental program of these animals was driven by the cell-autonomous inheritance of localised maternal determinants, rendered precise by the stereotyped pattern of invariant cell cleavages. Work in the past 20 years indeed identified several localised maternal determinants of the position of cleavage planes or of some early cell fates. The overwhelming majority of cells in the three germ layers, however, do not follow a cell-autonomous differentiation program. Instead, they respond to short-range signals, as described in this review. Careful analysis of cell-cell contacts suggests that a major function of the invariant position of cleavage plans, besides segregating competence factors, is to control the relative positions of inducing cells and those competent to respond. Surprisingly, while the cell lineage is very well conserved between the divergent species Halocynthia roretzi and Ciona intestinalis, the molecular nature of inducing signals can vary. The constraints on embryo anatomy thus appear stronger than those on the choice of individual regulatory molecules.

76 FR 69736 - Draft Toxicological Review of Vanadium Pentoxide: In Support of Summary Information on the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-09

... Toxicological Review of Vanadium Pentoxide: In Support of Summary Information on the Integrated Risk Information..., ``Toxicological Review of Vanadium Pentoxide: In Support of Summary Information on the Integrated Risk Information... Vanadium Pentoxide: In Support of Summary Information on the Integrated Risk Information System (IRIS)'' is...

The Influence of Vanadium Microalloying on the Production of Thin Slab Casting and Direct Rolled Steel Strip

NASA Astrophysics Data System (ADS)

Li, Yu; Milbourn, David

Vanadium microalloying is highly effective in high strength strip steels produced by thin slab casting and direct rolled process. Because of the high solubility of V(C,N) in austenite, vanadium is likely to remain in solution during casting, equalisation and rolling. Vanadium microalloyed steels have better hot ductility and are less prone to transverse cracking than niobium containing steels. Despite a coarse as-cast austenite grain size before rolling, significant grain refinement can be achieved in vanadium microalloyed steels by repeated recrystallization during rolling, resulting in a fine uniform ferrite microstructure in final strip. Almost all vanadium present in microalloyed steels is available to precipitate in ferrite as very fine particles, contributing to precipitation strengthening. Vanadium microalloyed steels show less sensitivity to rolling process variables and exhibit excellent combination of strength and toughness.

Fabrication of vanadium dioxide polycrystalline films with higher temperature coefficient of resistance

NASA Astrophysics Data System (ADS)

Li, Jinhua; Yuan, Ningyi; Jiang, Meiping; Kun, Li

2011-08-01

Vanadium Dioxide Polycrystalline Films with High Temperature Coefficient of Resistance(TCR) were fabricated by modified Ion Beam Enhanced Deposition(IBED) method. The TCR of the Un-doping VO2 was about -4%/K at room temperature after appropriate thermal annealing. The XRD results clearly showed that IBED polycrystalline VO2 films had a single [002] orientation of VO2(M). The TCR of 5at.%W and 7at.% Ta doped Vanadium Dioxide Polycrystalline Films were high up to -18%/K and -12%/K at room temperature, respectively. Using 7at.% Ta and 2at.% Ti co-doping, the TCR of the co-doped vanadium oxide film was -7%/K and without hysteresis during temperature increasing and decresing from 0-80°C. It should indicate that the W-doped vanadium dioxide films colud be used for high sensing IR detect and the Ta/Ti co-doped film without hysteresis is suitable for infrarid imaging application.

Spatial distribution of vanadium and microbial community responses in surface soil of Panzhihua mining and smelting area, China.

PubMed

Cao, Xuelong; Diao, Muhe; Zhang, Baogang; Liu, Hui; Wang, Song; Yang, Meng

2017-09-01

Spatial distribution of vanadium in surface soils from different processing stages of vanadium-bearing titanomagnetite in Panzhihua mining and smelting area (China) as well as responses of microbial communities including bacteria and fungi to vanadium were investigated by fieldwork and laboratory incubation experiment. The vanadium contents in this region ranged from 149.3 to 4793.6 mg kg -1 , exceeding the soil background value of vanadium in China (82 mg kg -1 ) largely. High-throughput DNA sequencing results showed bacterial communities from different manufacturing locations were quite diverse, but Bacteroidetes and Proteobacteria were abundant in all samples. The contents of organic matter, available P, available S and vanadium had great influences on the structures of bacterial communities in soils. Bacterial communities converged to similar structure after long-term (240 d) cultivation with vanadium containing medium, dominating by bacteria which can tolerate or reduce toxicities of heavy metals. Fungal diversities decreased after cultivation, but Ascomycota and Ciliophora were still the most abundant phyla as in the original soil samples. Results in this study emphasize the urgency of investigating vanadium contaminations in soils and provide valuable information on how vanadium contamination influences bacterial and fungal communities. Copyright © 2017 Elsevier Ltd. All rights reserved.

The toxicity of vanadium on gastrointestinal, urinary and reproductive system, and its influence on fertility and fetuses malformations.

PubMed

Wilk, Aleksandra; Szypulska-Koziarska, Dagmara; Wiszniewska, Barbara

2017-09-25

Vanadium is a transition metal that has a unique and beneficial effect on both humans and animals. For many years, studies have suggested that vanadium is an essential trace element. Its biological properties are of interest due to its therapeutic potential, including in the treatment of diabetes mellitus. Vanadium deficiencies can lead to a range of pathologies. However, excessive concentration of this metal can cause irreversible damage to various tissues and organs. Vanadium toxicity mainly manifests in gastrointestinal symptoms, including diarrhea, vomiting, and weight reduction. Vanadium also exhibits hepatotoxic and nephrotoxic properties, including glomerulonephritis and pyelonephritis. Vanadium compounds may also lead to partial degeneration of the seminiferous epithelium of the seminiferous tubules in the testes and can affect male fertility. This paper describes the harmful effects of vanadium on the morphology and physiology of both animal and human tissues, including the digestive system, the urinary tract, and the reproductive system. What is more, the following study includes data concerning the correlation between the above-mentioned metal and its influence on fertility and fetus malformations. Additionally, this research identifies the doses of vanadium which lead to pathological alterations becoming visible within tissues. Moreover, this study includes information about the protective efficacy of some substances in view of the toxicity of vanadium.

Superconducting and Magnetic Properties of Vanadium/iron Superlattices.

NASA Astrophysics Data System (ADS)

Wong, Hong-Kuen

A novel ultrahigh vacuum evaporator was constructed for the preparation of superlattice samples. The thickness control was much better than an atomic plane. With this evaporator we prepared V/Fe superlattice samples on (0001) sapphire substrates with different thicknesses. All samples showed a good bcc(110) structure. Mossbauer experiments showed that the interface mixing extended a distance of about one atomic plane indicating an almost rectangular composition profile. Because of this we were able to prepare samples with layer thickness approaching one atomic plane. Even with ultrathin Fe layers, the samples are ferromagnetic, at least at lower temperatures. Superparamagnetism and spin glass states were not seen. In the absence of an external field, the magnetic moments lie close to the film plane. In addition to this shape anisotropy, there is some uniaxial anisotropy. No magnetic dead layers have been observed. The magnetic moments within the Fe layers vary little with the distance from the interfaces. At the interfaces the Fe moment is reduced and an antiparallel moment is induced on the vanadium atoms. It is observed that ultrathin Fe layers behave in a 2D fashion when isolated by sufficiently thick vanadium layers; however, on thinning the vanadium layers, a magnetic coupling between the Fe layers has been observed. We also studied the superconducting properties of V/Fe sandwiches and superlattices. In both cases, the Fe layer, a strong pair-breaker, suppresses the superconducting transition temperature consistent with the current knowledge of the magnetic proximity effect. For the sandwiches with thin (thick) vanadium layers, the temperature dependence of the upper critical fields is consistent with the simple theory for a 2D (3D) superconductor. For the superlattices, when the vanadium layer is on the order of the BCS coherence length and the Fe layer is only a few atomic planes thick, a 2D-3D crossover has been observed in the temperature dependence of the

Quantitative assessment of Azumiobodo hoyamushi distribution in the tunic of soft tunic syndrome-affected ascidian Halocynthia roretzi using real-time polymerase chain reaction.

PubMed

Shin, Yun-Kyung; Nam, Ki-Woong; Park, Kwan Ha; Yoon, Jong-Man; Park, Kyung-Il

2014-11-26

The kinetoplastid parasite, Azumiobodo hoyamushi, is the causative agent of soft tunic syndrome (STS) in ascidians and leads to their mass mortality in Korean waters. This study was conducted to quantify A. hoyamushi density during the development of STS in the tunics of ascidians (Halocynthia roretzi) using real-time polymerase chain reaction (qPCR). The infection intensity of A. hoyamushi, as measured by qPCR, varied depending on the part of the tunic analyzed, as well as the stage of STS development. The highest infection intensity was recorded in the tunics of the siphons. The infection intensity of A. hoyamushi in the siphons was only 2.9 cell/tunic (area, 0.25 cm(2)) or 106.0 cell/gram tunic (GT) in the early phase of STS, but this value increased dramatically to 16,066 cells/tunic (0.25 cm(2)) or 617,004 cell/GT at the time of death. The number of A. hoyamushi parasites increased gradually and their distribution spread from the siphons to the other parts of the tunics. qPCR enabled the quantitation of A. hoyamushi and the results revealed that parasite density increased as STS progressed. In addition, our results suggested that the siphons might function as the portal of entry for A. hoyamushi during infection.

Cottonseed meal, dehydrated grass and ascorbic acid as dietary factors preventing toxicity of vanadium for the chick

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

Berg, L.R.; Lawrence, W.W.

1971-01-01

Studies have been conducted which show that the replacement of 5% sucrose in a sucrose-fish meal diet for chicks with degossypolized cottonseed meal prevents the toxicity of 20 ppm added vanadium. The addition of 5% dehydrated grass to the same ration markedly reduced the toxicity symptoms. No such reduction in vanadium toxicity resulted when soybean meal, corn gluten meal, meat meal, fish meal, casein, isolated soybean protein, zein or wheat gluten were added to the ration. No evidence was found that the gossypol remaining in the cottonseed meal was the detoxifying agent. The addition of 0.25 to 0.50% ascorbic acidmore » to the sucrose-fish meal basal ration prevented the toxic symptoms resulting from the addition of 20 ppm vanadium derived from HN/sub 4/VO/sub 3/. The vanadium derived from VOSO/sub 4/ and VOCl/sub 2/ (vanadium valence 4) was as toxic as vanadium derived from HN/sub 4/VO/sub 3/ (V = valence 5). This leads one to question that the action of ascorbic acid in reducing vanadium toxicity is through its property of a reducing agent which might change the vanadium in VH/sub 4/VO/sub 3/ to a lower valence, presumably less toxic.« less

Vanadium Microalloyed High Strength Martensitic Steel Sheet for Hot-Dip Coating

NASA Astrophysics Data System (ADS)

Hutchinson, Bevis; Komenda, Jacek; Martin, David

Cold rolled steels with various vanadium and nitrogen levels have been treated to simulate the application of galvanizing and galvannealing to hardened martensitic microstructures. Strength levels were raised 100-150MPa by alloying with vanadium, which mitigates the effect of tempering. This opens the way for new ultra-high strength steels with corrosion resistant coatings produced by hot dip galvanising.

Effect of Sulfuric and Triflic Acids on the Hydration of Vanadium Cations: An ab Initio Study.

PubMed

Sepehr, Fatemeh; Paddison, Stephen J

2015-06-04

Vanadium redox flow batteries (VRFBs) may be a promising solution for large-scale energy storage applications, but the crossover of any of the redox active species V(2+), V(3+), VO(2+), and VO2(+) through the ion exchange membrane will result in self-discharge of the battery. Hence, a molecular level understanding of the states of vanadium cations in the highly acidic environment of a VRFB is needed. We examine the effects of sulfuric and triflic (CF3SO3H) acids on the hydration of vanadium species as they mimic the electrolyte and functional group of perfluorosulfonic acid (PFSA) membranes. Hybrid density functional theory in conjunction with a continuum solvation model was utilized to obtain the local structures of the hydrated vanadium cations in proximity to H2SO4, CF3SO3H, and their conjugate anions. The results indicate that none of these species covalently bond to the vanadium cations. The hydration structure of V(3+) is more distorted than that of V(2+) in an acidic medium. The oxo-group of VO2(+) is protonated by either acid, in contrast to VO(2+) which is not protonated. The atomic partial charge of the four oxidation states of vanadium varies from +1.7 to +2.0. These results provide the local solvation structures of vanadium cations in the VRFBs environment that are directly related to the electrolytes stability and diffusion of vanadium ions into the membrane.

Potential speciation of morphotypes in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago, Japan

NASA Astrophysics Data System (ADS)

Hirose, M.; Yokobori, S.; Hirose, E.

2009-03-01

Four morphotypes are recognized in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago: three color morphs (white, dark gray, and brown) of small-type colonies and one large-type colony (white with gray patches). The genetic variation among these four morphotypes was investigated by constructing phylogenetic trees based on a 401-bp fragment of the cytochrome oxidase subunit I (COI) gene of 29 specimens collected from five islands (Okinawajima, Sesokojima, Ikeijima, Kumejima, and Ishigakijima). The results support the monophyly of the genus Didemnum and that of the four morphotypes of D. molle. Moreover, the phylogenetic trees discriminated four clades corresponding to each morphotype. The geographic differences of the sequences were much smaller than the differences among the morphotypes, suggesting that the four morphotypes in D. molle are discrete sibling species.

Allergic reaction to vanadium causes a diffuse eczematous eruption and titanium alloy orthopedic implant failure.

PubMed

Engelhart, Sally; Segal, Robert J

2017-04-01

Allergy as a cause of adverse outcomes in patients with implanted orthopedic hardware is controversial. Allergy to titanium-based implants has not been well researched, as titanium is traditionally thought to be inert. We highlight the case of a patient who developed systemic dermatitis and implant failure after surgical placement of a titanium alloy (Ti6Al4V) plate in the left foot. The hardware was removed and the eruption cleared in the following weeks. The plate and screws were submitted for metal analysis. The elemental composition of both the plate and screws included 3 major elements-titanium, aluminum, and vanadium-as well as trace elements. Metal analysis revealed that the plate and screws had different microstructures, and electrochemical studies demonstrated that galvanic corrosion could have occurred between the plate and screws due to their different microstructures, contributing to the release of vanadium in vivo. The patient was patch tested with several metals including components of the implant and had a positive patch test reaction only to vanadium trichloride. These findings support a diagnosis of vanadium allergy and suggests that clinicians should consider including vanadium when patch testing patients with a suspected allergic reaction to vanadium-containing implants.

Lithium Metal-Copper Vanadium Oxide Battery with a Block Copolymer Electrolyte

DOE PAGES

Devaux, Didier; Wang, Xiaoya; Thelen, Jacob L.; ...

2016-09-08

Lithium (Li) batteries comprising multivalent positive active materials such as copper vanadium oxide have high theoretical capacity. These batteries with a conventional liquid electrolyte exhibit limited cycle life because of copper dissolution into the electrolyte. In this paper, we report here on the characterization of solid-state Li metal batteries with a positive electrode based on α-Cu 6.9V 6O 18.9 (α-CuVO 3). We replaced the liquid electrolyte by a nanostructured solid block copolymer electrolyte comprising of a mixture of polystyrene-b-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. In situ X-ray diffraction was used to follow the Li insertion/de-insertion mechanism into themore » α-CuVO 3 host material and its reversibility. In situ X-ray scattering revealed that the multistep electrochemical reactions involved are similar in the presence of liquid or solid electrolyte. The capacity fade of the solid-state batteries is less rapid than that of α-CuVO 3–Li metal batteries with a conventional liquid electrolyte. Hard X-ray microtomography revealed that upon cycling, voids and Cu-rich agglomerates were formed at the interface between the Li metal and the SEO electrolyte. Finally, the void volume and the volume occupied by the Cu-rich agglomerates were independent of C-rate and cycle number.« less

Protection from Oxidative Stress in Immunocytes of the Colonial Ascidian Botryllus schlosseri: Transcript Characterization and Expression Studies.

PubMed

Franchi, Nicola; Ballin, Francesca; Ballarin, Loriano

2017-02-01

Botryllus schlosseri is a cosmopolitan colonial ascidian that undergoes cyclical generation changes, or take-overs, during which adult zooids are resorbed and replaced by their buds. At take-over, adult tissues undergo diffuse apoptosis and effete cells are massively ingested by circulating phagocytes, with a consequent increase in oxygen consumption and in production of reactive oxygen species (ROS). The latter are responsible for the death of phagocytes involved in the clearance of apoptotic cells and corpses by phagocytosis-induced apoptosis. However, the majority of phagocytes and hemocytes do not die, even if they experience oxidative stress. This fact suggests the presence of detoxification mechanisms assuring their protection. To test this assumption, we searched for transcripts of genes involved in detoxification in the transcriptome of B. schlosseri. We identified and characterized transcripts for Cu/Zn superoxide dismutase (SOD), γ-glutamyl-cysteine ligase modulatory subunit (GCLM), glutathione synthase (GS), and two glutathione peroxidases (i.e., GPx3 and GPx5), all involved in protection from ROS. We also carried out a phylogenetic analysis of the putative amino acid sequences, confirming their similarity to their vertebrate counterparts, and studied the location of their mRNAs by in situ hybridization on hemocyte monolayers. We also analyzed gene transcription during the colonial blastogenetic cycle, which is the interval of time between one take-over and the next, by qRT-PCR. In addition, we investigated the effects of cadmium (Cd), an inducer of oxidative stress, on gene transcription. Our results indicated that i) antioxidant gene expression is modulated in the course of the blastogenetic cycle and upon exposure to Cd, and ii) hemocytes synthesize both enzymatic and nonenzymatic antioxidants, in line with the idea that they represent a major detoxification system for ascidians.

Why Antidiabetic Vanadium Complexes are Not in the Pipeline of “Big Pharma” Drug Research? A Critical Review

PubMed Central

Scior, Thomas; Guevara-Garcia, Jose Antonio; Do, Quoc-Tuan; Bernard, Philippe; Laufer, Stefan

2016-01-01

Public academic research sites, private institutions as well as small companies have made substantial contributions to the ongoing development of antidiabetic vanadium compounds. But why is this endeavor not echoed by the globally operating pharmaceutical companies, also known as “Big Pharma”? Intriguingly, today’s clinical practice is in great need to improve or replace insulin treatment against Diabetes Mellitus (DM). Insulin is the mainstay therapeutically and economically. So, why do those companies develop potential antidiabetic drug candidates without vanadium (vanadium-free)? We gathered information about physicochemical and pharmacological properties of known vanadium-containing antidiabetic compounds from the specialized literature, and converted the data into explanations (arguments, the “pros and cons”) about the underpinnings of antidiabetic vanadium. Some discoveries were embedded in chronological order while seminal reviews of the last decade about the Medicinal chemistry of vanadium and its history were also listed for further understanding. In particular, the concepts of so-called “noncomplexed or free” vanadium species (i.e. inorganic oxido-coordinated species) and “biogenic speciation” of antidiabetic vanadium complexes were found critical and subsequently documented in more details to answer the question. PMID:26997154

Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage.

PubMed

Charles, Daniel Scott; Feygenson, Mikhail; Page, Katharine; Neuefeind, Joerg; Xu, Wenqian; Teng, Xiaowei

2017-05-23

Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because the large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183 mAh g -1 in half-cells at a scan rate of 5 mV s -1 , corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5 mAh g -1 in full cells after 5,000 cycles at 10 C). The promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.

Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage

DOE PAGES

Charles, Daniel Scott; Feygenson, Mikhail; Page, Katharine; ...

2017-05-23

Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183 mAh g -1 in half-cells at a scan rate ofmore » 5 mV s -1, corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5 mAh g -1 in full-cells after 5,000 cycles at 10 C). Finally, the promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.« less

Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage

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

Charles, Daniel Scott; Feygenson, Mikhail; Page, Katharine

Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183 mAh g -1 in half-cells at a scan rate ofmore » 5 mV s -1, corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5 mAh g -1 in full-cells after 5,000 cycles at 10 C). Finally, the promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.« less

The habitat engineering tunicate Microcosmus sabatieri Roule, 1885 and its associated peracarid epifauna

NASA Astrophysics Data System (ADS)

Voultsiadou, Eleni; Pyrounaki, Maria-Myrto; Chintiroglou, Chariton

2007-08-01

The solitary ascidian Microcosmus sabatieri is a common ecosystem engineering species on hard bottom sublittoral communities in the Eastern Mediterranean. Peracarida are common inhabitants of biological substrata, such as algae, sponges and ascidians and have been proven to be very sensitive to changes in environmental conditions. The aim of this study was to present and analyse, for the first time, the structure of the peracarid epifaunal assemblage inhabiting this Mediterranean endemic, edible and commercially exploited species. During sampling in the North Aegean Sea, 41 specimens were collected and examined for their peracarid epifauna. Overall, 38 peracarid species were identified, a high number in comparison to those recorded in the few other relevant studies on ascidian epifauna. The great majority of the species were amphipods. By contrast, in terms of abundance, tanaidaceans was the dominant taxon, with Leptochelia savigni being by far the most dominant species. Tube-dwelling suspension-feeders dominated the peracarid epifauna of this tunicate. The suspension feeding mode of epifaunal peracarids is possibly favoured by the high filtration rate of M. sabatieri which is large sized and has an extensive branchial surface. It is suggested that the tube-dwelling habit of tanaidaceans and some amphipods offering extra protection, may further explain their dominance as elements of the epifauna, in contrast to other inquiline peracarids which prefer to search for shelter inside the canals of sponges or, in a few cases inside the mantle cavity of ascidians. Differences in peracarid abundance among the ascidian specimens were attributed to the reproductive and dispersal habits of the former. Species richness, abundance and diversity of the motile peracarid epifauna was dependent on the biomass of the ascidian, but most strongly on the biomass of the sessile epibiontic organisms, such as algae and sponges which, in some cases, had a higher biomass than the ascidian

Effect of vanadium on colonic aberrant crypt foci induced in rats by 1,2 Dimethyl hydrazine

PubMed Central

Kanna, P Suresh; Mahendrakumar, CB; Chakraborty, T; Hemalatha, P; Banerjee, Pratik; Chatterjee, M

2003-01-01

AIM: To investigate the chemo preventive effects of vanadium on rat colorectal carcinogenesis induced by 1,2-dimethylhydrazine (DMH). METHODS: Male Sprague-Dawley Rats were randomly divided into four groups. Rats in Group A received saline vehicle alone for 16 weeks. Rats in Group B were given DMH injection once a week intraperitoneally for 16 weeks; rats in Group C, with the same DMH treatment as in the Group B, but received 0.5-ppm vanadium in the form ammonium monovanadate ad libitum in drinking water. Rats in the Group D received vanadium alone as in the Group C without DMH injection. RESULTS: Aberrant crypt foci (ACF) were formed in animals in DMH-treated groups at the end of week 16. Compared to DMH group, vanadium treated group had less ACF (P < 0.001). At the end of week 32, all rats in DMH group developed large intestinal tumors. Rats treated with vanadium contained significantly few colonic adenomas and carcinomas (P < 0.05) compared to rats administered DMH only. In addition, a significant reduction (P < 0.05) in colon tumor burden (sum of tumor sizes per animal) was also evident in animals of Group C when compared to those in rats of carcinogen control Group B. The results also showed that vanadium significantly lowered PCNA index in ACF (P < 0.005). Furthermore, vanadium supplementation also elevated liver GST and Cyt P-450 activities (P < 0.001 and P < 0.02, respectively). CONCLUSION: Vanadium in the form of ammonium monovanadate supplemented in drinking water ad libitum has been found to be highly effective in reducing tumor incidence and preneoplastic foci on DMH-induced colorectal carcinogenesis. These findings suggest that vanadium administration can suppress colon carcinogenesis in rats. PMID:12717849

Critical V2O5/TeO2 Ratio Inducing Abrupt Property Changes in Vanadium Tellurite Glasses.

PubMed

Kjeldsen, Jonas; Rodrigues, Ana C M; Mossin, Susanne; Yue, Yuanzheng

2014-12-26

Transition metal containing glasses have unique electrical properties and are therefore often used for electrochemical applications, such as in batteries. Among oxide glasses, vanadium tellurite glasses exhibit the highest electronic conductivity and thus the high potential for applications. In this work, we investigate how the dynamic and physical properties vary with composition in the vanadium tellurite system. The results show that there exists a critical V(2)O(5) concentration of 45 mol %, above which the local structure is subjected to a drastic change with increasing V(2)O(5), leading to abrupt changes in both hardness and liquid fragility. Electronic conductivity does not follow the expected correlation to the valence state of the vanadium as predicted by the Mott-Austin equation but shows a linear correlation to the mean distance between vanadium ions. These findings could contribute to designing optimum vanadium tellurite compositions for electrochemical devices. The work gives insight into the mechanism of electron conduction in the vanadium tellurite systems.

Improved capacitance characteristics of electrospun ACFs by pore size control and vanadium catalyst.

PubMed

Im, Ji Sun; Woo, Sang-Wook; Jung, Min-Jung; Lee, Young-Seak

2008-11-01

Nano-sized carbon fibers were prepared by using electrospinning, and their electrochemical properties were investigated as a possible electrode material for use as an electric double-layer capacitor (EDLC). To improve the electrode capacitance of EDLC, we implemented a three-step optimization. First, metal catalyst was introduced into the carbon fibers due to the excellent conductivity of metal. Vanadium pentoxide was used because it could be converted to vanadium for improved conductivity as the pore structure develops during the carbonization step. Vanadium catalyst was well dispersed in the carbon fibers, improving the capacitance of the electrode. Second, pore-size development was manipulated to obtain small mesopore sizes ranging from 2 to 5 nm. Through chemical activation, carbon fibers with controlled pore sizes were prepared with a high specific surface and pore volume, and their pore structure was investigated by using a BET apparatus. Finally, polyacrylonitrile was used as a carbon precursor to enrich for nitrogen content in the final product because nitrogen is known to improve electrode capacitance. Ultimately, the electrospun activated carbon fibers containing vanadium show improved functionality in charge/discharge, cyclic voltammetry, and specific capacitance compared with other samples because of an optimal combination of vanadium, nitrogen, and fixed pore structures.

Vanadium As a Potential Membrane Material for Carbon Capture: Effects of Minor Flue Gas Species.

PubMed

Yuan, Mengyao; Liguori, Simona; Lee, Kyoungjin; Van Campen, Douglas G; Toney, Michael F; Wilcox, Jennifer

2017-10-03

Vanadium and its surface oxides were studied as a potential nitrogen-selective membrane material for indirect carbon capture from coal or natural gas power plants. The effects of minor flue gas components (SO 2 , NO, NO 2 , H 2 O, and O 2 ) on vanadium at 500-600 °C were investigated by thermochemical exposure in combination with X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and in situ X-ray diffraction (XRD). The results showed that SO 2 , NO, and NO 2 are unlikely to have adsorbed on the surface vanadium oxides at 600 °C after exposure for up to 10 h, although NO and NO 2 may have exhibited oxidizing effects (e.g., exposure to 250 ppmv NO/N 2 resulted in an 2.4 times increase in surface V 2 O 5 compared to exposure to just N 2 ). We hypothesize that decomposition of surface vanadium oxides and diffusion of surface oxygen into the metal bulk are both important mechanisms affecting the composition and morphology of the vanadium membrane. The results and hypothesis suggest that the carbon capture performance of the vanadium membrane can potentially be strengthened by material and process improvements such as alloying, operating temperature reduction, and flue gas treatment.

Inverse association of plasma vanadium levels with newly diagnosed type 2 diabetes in a Chinese population.

PubMed

Wang, Xia; Sun, Taoping; Liu, Jun; Shan, Zhilei; Jin, Yilin; Chen, Sijing; Bao, Wei; Hu, Frank B; Liu, Liegang

2014-08-15

Vanadium compounds have been proposed to have beneficial effects on the pathogenesis and complications of type 2 diabetes. Our objective was to evaluate the association between plasma vanadium levels and type 2 diabetes. We performed a case-control study involving 1,598 Chinese subjects with or without newly diagnosed type 2 diabetes (December 2004-December 2007). Cases and controls were frequency-matched by age and sex. Plasma vanadium concentrations were measured and compared between groups. Analyses showed that plasma vanadium concentrations were significantly lower in cases with newly diagnosed type 2 diabetes than in controls (P = 0.001). Mean plasma vanadium levels in participants with and without diabetes were 1.0 μg/L and 1.2 μg/L, respectively. Participants in the highest quartile of plasma vanadium concentration had a notably lower risk of newly diagnosed type 2 diabetes (odds ratio = 0.26, 95% confidence interval: 0.19, 0.35; P < 0.001), compared with persons in the lowest quartile. The trend remained significant after adjustment for known risk factors and in further stratification analyses. Our results suggested that plasma vanadium concentrations were inversely associated with newly diagnosed type 2 diabetes in this Chinese population. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cloud point extraction of vanadium in pharmaceutical formulations, dialysate and parenteral solutions using 8-hydroxyquinoline and nonionic surfactant.

PubMed

Khan, Sumaira; Kazi, Tasneem G; Baig, Jameel A; Kolachi, Nida F; Afridi, Hassan I; Wadhwa, Sham Kumar; Shah, Abdul Q; Kandhro, Ghulam A; Shah, Faheem

2010-10-15

A cloud point extraction (CPE) method has been developed for the determination of trace quantity of vanadium ions in pharmaceutical formulations (PF), dialysate (DS) and parenteral solutions (PS). The CPE of vanadium (V) using 8-hydroxyquinoline (oxine) as complexing reagent and mediated by nonionic surfactant (Triton X-114) was investigated. The parameters that affect the extraction efficiency of CPE, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of CPE of V was checked by standard addition method in real samples. The extracted surfactant-rich phase was diluted with nitric acid in ethanol, prior to subjecting electrothermal atomic absorption spectrometry. Under these conditions, the preconcentration of 50 mL sample solutions, allowed raising an enrichment factor of 125-fold. The lower limit of detection obtained under the optimal conditions was 42 ng/L. The proposed method has been successfully applied to the determination of trace quantity of V in various pharmaceutical preparations with satisfactory results. The concentration ranges of V in PF, DS and PS samples were found in the range of 10.5-15.2, 0.65-1.32 and 1.76-6.93 microg/L, respectively. 2010 Elsevier B.V. All rights reserved.

Self-repairing vanadium-zirconium composite conversion coating for aluminum alloys

NASA Astrophysics Data System (ADS)

Zhong, Xin; Wu, Xiaosong; Jia, Yuyu; Liu, Yali

2013-09-01

In this paper, new self-repairing vanadium-zirconium composite conversion coating was prepared and investigated by Electrochemical impedance spectra (EIS), Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. EIS results showed that V-Zr conversion coating with hydrogen peroxide modified (VZO) revealed an increasing corrosion resistance in corrosive media which meant a certain self-repairing effect. SEM comparison photos also disclosed that VZO treated with scratches was gradually ameliorated from the initial cracked configuration to fewer cracks and more fillers through an immersion of 3.5% NaCl solution. XPS results demonstrated that the content of vanadium on VZO increased and zirconium declined when immersed in the corrosive solution. This explained further that the self-repairing ability could be related to vanadium. From the above results, we inferred possible structures of VZO and proposed that self-repairing effect was achieved through a hydrolysis condensation polymerization process of vanadate in the localized corrosion area.

Bipolar resistive switching in room temperature grown disordered vanadium oxide thin-film devices

NASA Astrophysics Data System (ADS)

Wong, Franklin J.; Sriram, Tirunelveli S.; Smith, Brian R.; Ramanathan, Shriram

2013-09-01

We demonstrate bipolar switching with high OFF/ON resistance ratios (>104) in Pt/vanadium oxide/Cu structures deposited entirely at room temperature. The SET (RESET) process occurs when negative (positive) bias is applied to the top Cu electrode. The vanadium oxide (VOx) films are amorphous and close to the vanadium pentoxide stoichiometry. We also investigated Cu/VOx/W structures, reversing the position of the Cu electrode, and found the same polarity dependence with respect to the top and bottom electrodes, which suggests that the bipolar nature is linked to the VOx layer itself. Bipolar switching can be observed at 100 °C, indicating that it not due to a temperature-induced metal-insulator transition of a vanadium dioxide second phase. We discuss how ionic drift can lead to the bipolar electrical behavior of our junctions, similar to those observed in devices based on several other defective oxides. Such low-temperature processed oxide switches could be of relevance to back-end or package integration processing schemes.

Effect of Mechanical Activation Treatment on the Recovery of Vanadium from Converter Slag

NASA Astrophysics Data System (ADS)

Xiang, Junyi; Huang, Qingyun; Lv, Xuewei; Bai, Chenguang

2017-10-01

The high roasting temperature and low leaching efficiency of vanadium from vanadium-bearing converter slag are regarded as the main factors significantly influencing the application of calcification roasting-acid leaching processes in the cleaner production of vanadium. In this study, a mechanical activation treatment was performed to enhance the extraction of vanadium from converter slag. The enhancement effects obtained from mechanical activation were comprehensively evaluated through indices such as the roasting temperature and leaching efficiency. The effects of mechanical activation time, roasting temperature, leaching temperature, solid to liquid ratio, particle size, and acid concentration on the leaching efficiency were investigated. Microstructure morphology and elemental analyses of the raw materials and leaching residue were also investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results demonstrated that the mechanical activation significantly decreased the optimum roasting temperature from 1173 K to 1073 K (900 °C to 800 °C) and increased the leaching efficiency from 86.0 to 90.9 pct.

Effect of tea polyphenols on production performance, egg quality, and hepatic antioxidant status of laying hens in vanadium-containing diets.

PubMed

Yuan, Z H; Zhang, K Y; Ding, X M; Luo, Y H; Bai, S P; Zeng, Q F; Wang, J P

2016-07-01

This study was conducted to determine the effect of tea polyphenols (TP) on production performance, egg quality, and hepatic-antioxidant status of laying hens in vanadium-containing diets. A total of 300 Lohman laying hens (67 wk old) were used in a 1 plus 3 × 3 experiment design in which hens were given either a diet without vanadium and TP supplementation (control) or diets supplemented with 5, 10, or 15 mg V/kg and TP (0, 600, 1,000 mg/kg) diets for 8 wk, which included 2 phases: a 5-wk accumulation phase and a 3-wk depletion phase. During the accumulation phase, dietary vanadium addition decreased (linear, P < 0.01) albumen height and Haugh unit (HU), and TP supplementation mitigated (linear effect, P < 0.01) this reduction effect induced by vanadium. Eggshell thickness (linear, P < 0.01), redness (linear and quadratic, P < 0.05), and yellowness (linear and quadratic, P < 0.05) were decreased by vanadium and increased by the effect of TP when a vanadium-containing diet was fed. In the depletion phase, the bleaching effect on eggshells induced by vanadium disappeared one wk after vanadium withdrawal. Eggshell thickness, eggshell strength, albumen height, and HU were lower (P < 0.05) in the 15 mg/kg vanadium group compared with the control diet until 2 wk post vanadium challenge, but hens fed 15 mg/kg vanadium and 600 mg/kg TP showed no difference from the control diet only after 1 wk withdrawal. In the liver, the activity of glutathione S-transferases and glutathione peroxidase was increased (linear, P < 0.01) with the TP addition at 5 wk in the accumulation phase in the vanadium-containing diet; the malondialdehyde content increased (linear effect, P = 0.02) with the addition of vanadium. The results indicate that supplementation of 10 and 15 mg/kg vanadium resulted in reduced albumen quality, bleaching effect on eggshell color, and antioxidant stress in the liver. The effect of TP addition can prevent laying hens from the adverse effect of vanadium on egg

Ascidian sperm glycosylphosphatidylinositol-anchored CRISP-like protein as a binding partner for an allorecognizable sperm receptor on the vitelline coat.

PubMed

Urayama, Satoshi; Harada, Yoshito; Nakagawa, Yoko; Ban, Susumu; Akasaka, Mari; Kawasaki, Nana; Sawada, Hitoshi

2008-08-01

Although ascidians are hermaphroditic, many species including Halocynthia roretzi are self-sterile. We previously reported that a vitelline coat polymorphic protein HrVC70, consisting of 12 EGF (epidermal growth factor)-like repeats, is a candidate allorecognition protein in H. roretzi, because the isolated HrVC70 shows higher affinity to nonself-sperm than to self-sperm. Here, we show that a sperm 35-kDa glycosylphosphatidylinositol-anchored CRISP (cysteine-rich secretory protein)-like protein HrUrabin in a low density detergent-insoluble membrane fraction is a physiological binding partner for HrVC70. We found that HrVC70 specifically interacts with HrUrabin, which had been separated by SDS-PAGE and transferred onto a nitrocellulose membrane. HrUrabin has an N-linked sugar chain, essential for binding to HrVC70. HrUrabin mRNA is expressed in the testis but not in the ovary, and the protein appears to be localized on the surface of sperm head and tail. Anti-HrUrabin antibody, which neutralizes the interaction between HrUrabin and HrVC70, potently inhibited fertilization and allorecognizable sperm-binding to HrVC70-agarose. However, no significant difference in the binding ability of HrUrabin to HrVC70 was observed in autologous and allogeneic combinations by Far Western analyses. These results indicate that sperm-egg binding in H. roretzi is mediated by the molecular interaction between HrUrabin on the sperm surface and HrVC70 on the vitelline coat, but that HrUrabin per se is unlikely to be a direct allorecognition protein.

Adsorption of Vanadium (V) from SCR Catalyst Leaching Solution and Application in Methyl Orange.

PubMed

Sha, Xuelong; Ma, Wei; Meng, Fanqing; Wang, Ren; Fuping, Tian; Wei, Linsen

2016-12-01

  In this study, we explored an effective and low-cost catalyst and its adsorption capacity and catalytic capacity for Methyl Orange Fenton oxidation degradation were investigated. The catalyst was directly prepared by reuse of magnetic iron oxide (Fe3O4) after saturated adsorption of vanadium (V) from waste SCR (Selective Catalytic Reduction) catalyst. The obtained catalyst was characterized by FTIR, XPS and the results showed that vanadium (V) adsorption process of Fe3O4 nanoparticles was non-redox reaction. The effects of pH, adsorption kinetics and equilibrium isotherms of adsorption were assessed. Adsorption of vanadium (V) ions by Fe3O4 nanoparticles could be well described by the Sips isotherm model which controlled by the mixed surface reaction and diffusion (MSRDC) adsorption kinetic model. The results show that vanadium (V) was mainly adsorbed on external surface of the Fe3O4 nanoparticles. The separation-recovering tungsten (VI) and vanadium (V) from waste SCR catalyst alkaline solution through pH adjustment was also investigated in this study. The results obtained from the experiments indicated that tungsten (VI) was selectively adsorbed from vanadium (V)/tungsten (VI) mixed solution in certain acidic condition by Fe3O4 nanoparticle to realize their recovery. Tungsten (V) with some impurity can be obtained by releasing from adsorbent, which can be confirmed by ICP-AES. The Methyl Orange degradation catalytic performance illustrated that the catalyst could improve Fenton reaction effectively at pH = 3.0 compare to Fe3O4 nanoparticles alone. Therefore, Fe3O4 nanoparticle adsorbed vanadium (V) has a potential to be employed as a heterogeneous Fenton-like catalyst in the present contribution, and its catalytic activity was mainly evaluated in terms of the decoloration efficiency of Methyl Orange.

Effect of vanadium doping on structural and magnetic properties of defective nano-nickel ferrite

NASA Astrophysics Data System (ADS)

Heiba, Zein K.; Mohamed, Mohamed Bakr; Wahba, Adel Maher; Almalowi, M. I.

2018-04-01

Nano-nickel ferrites defected by vanadium doping (NiV x Fe2-1.67 x O4, 0 ≤ x ≤ 0.25) were prepared using a simple sol gel method. Rietveld analysis revealed a nonmonotonic change in lattice parameter, oxygen parameter and magnetization upon doping with vanadium. Cation distributions suggested from either Rietveld analysis or from experimental magnetic moments were in a good agreement. For low doping values ( x = 0.05), vanadium was residing mainly in octahedral sites, while for samples with vanadium content ( x ≥ 0.1) a significant part of vanadium ions resided at tetrahedral sites; a result which has been confirmed by the analysis of Fourier-transform infrared (FTIR) spectrums obtained for the samples. The transmission electron microscope (TEM) image showed fine spherical particles with size of ˜ 11 nm. All samples showed a superparamagnetic nature with a nonmonotonic change of either magnetization ( M S) or coercivity (H C) with the content of nonmagnetic V5+. The cation occupancies indicated presence of an enormous number of vacancies through doping with high valence cation V5+, making present samples potential electrodes for Li- or Na-ion batteries.

Vanadium(IV/V) complexes of Triapine and related thiosemicarbazones: Synthesis, solution equilibrium and bioactivity.

PubMed

Kowol, Christian R; Nagy, Nóra V; Jakusch, Tamás; Roller, Alexander; Heffeter, Petra; Keppler, Bernhard K; Enyedy, Éva A

2015-11-01

The stoichiometry and thermodynamic stability of vanadium(IV/V) complexes of Triapine and two related α(N)-heterocyclic thiosemicarbazones (TSCs) with potential antitumor activity have been determined by pH-potentiometry, EPR and (51)V NMR spectroscopy in 30% (w/w) dimethyl sulfoxide/water solvent mixtures. In all cases, mono-ligand complexes in different protonation states were identified. Dimethylation of the terminal amino group resulted in the formation of vanadium(IV/V) complexes with considerably higher stability. Three of the most stable complexes were also synthesized in solid state and comprehensively characterized. The biological evaluation of the synthesized vanadium complexes in comparison to the metal-free ligands in different human cancer cell lines revealed only minimal influence of the metal ion. Thus, in addition the coordination ability of salicylaldehyde thiosemicarbazone (STSC) to vanadium(IV/V) ions was investigated. The exchange of the pyridine nitrogen of the α(N)-heterocyclic TSCs to a phenolate oxygen in STSC significantly increased the stability of the complexes in solution. Finally, this also resulted in increased cytotoxicity activity of a vanadium(V) complex of STSC compared to the metal-free ligand. Copyright © 2015 Elsevier Inc. All rights reserved.

Removal of arsenic, vanadium, and/or nickel compounds from petroliferous liquids

DOEpatents

Fish, R.H.

1985-05-17

Described is a process for removing arsenic, vanadium, and/or nickel from petroliferous derived liquids (shale oil, SRC, etc.) by contacting said liquid at an elevated temperature with a divinylbenzene-crosslinked polystyrene having catechol ligands anchored thereon. For vanadium and nickel removal an amine, preferably a diamine is included. Also, described is a process for regenerating spent catecholated polystyrene by removal of the arsenic, vanadium, and/or nickel bound to it from contacting petroliferous liquid as described above and involves: treating the spent polymer containing any vanadium and/or nickel with an aqueous acid to achieve an acid pH; and, separating the solids from the liquid; and then treating said spent catecholated polystyrene, at a temperature in the range of about 20/sup 0/ to 100/sup 0/C with an aqueous solution of at least one carbonate and/or bicarbonate of ammonium, alkali and alkaline earth metals, said solution having a pH between about 8 and 10; and, separating the solids and liquids from each other. Preferably the regeneration treatment of arsenic containing catecholated polymer is in two steps wherein the first step is carried out with an aqueous alcoholic carbonate solution containing lower alkyl alcohol, and, the steps are repeated using a bicarbonate.

Removal of arsenic, vanadium, and/or nickel compounds from petroliferous liquids

DOEpatents

Fish, Richard H.

1986-01-01

Described is a process for removing arsenic, vanadium, and/or nickel from petroliferous derived liquids by contacting said liquid at an elevated temperature with a divinylbenzene-crosslinked polystyrene having catechol ligands anchored thereon. For vanadium and nickel removal an amine, preferably a diamine is included. Also, described is a process for regenerating spent catecholated polystyrene by removal of the arsenic, vanadium, and/or nickel bound to it from contacting petroliferous liquid as described above and involves: treating the spent polymer containing any vanadium and/or nickel with an aqueous acid to achieve an acid pH; and, separating the solids from the liquid; and then treating said spent catecholated polystyrene, at a temperature in the range of about 20.degree. to 100.degree. C. with an aqueous solution of at least one carbonate and/or bicarbonate of ammonium, alkali and alkaline earth metals, said solution having a pH between about 8 and 10; and, separating the solids and liquids from each other. Preferably the regeneration treatment of arsenic containing catecholated polymer is in two steps wherein the first step is carried out with an aqueous alcoholic carbonate solution containing lower alkyl alcohol, and, the steps are repeated using a bicarbonate.

Real-time monitoring of capacity loss for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Wei, Zhongbao; Bhattarai, Arjun; Zou, Changfu; Meng, Shujuan; Lim, Tuti Mariana; Skyllas-Kazacos, Maria

2018-06-01

The long-term operation of the vanadium redox flow battery is accompanied by ion diffusion across the separator and side reactions, which can lead to electrolyte imbalance and capacity loss. The accurate online monitoring of capacity loss is therefore valuable for the reliable and efficient operation of vanadium redox flow battery system. In this paper, a model-based online monitoring method is proposed to detect capacity loss in the vanadium redox flow battery in real time. A first-order equivalent circuit model is built to capture the dynamics of the vanadium redox flow battery. The model parameters are online identified from the onboard measureable signals with the recursive least squares, in seeking to keep a high modeling accuracy and robustness under a wide range of working scenarios. Based on the online adapted model, an observer is designed with the extended Kalman Filter to keep tracking both the capacity and state of charge of the battery in real time. Experiments are conducted on a lab-scale battery system. Results suggest that the online adapted model is able to simulate the battery behavior with high accuracy. The capacity loss as well as the state of charge can be estimated accurately in a real-time manner.

Effect of Vanadyl Rosiglitazone, a New Insulin-Mimetic Vanadium Complexes, on Glucose Homeostasis of Diabetic Mice.

PubMed

Jiang, Pingzhe; Dong, Zhen; Ma, Baicheng; Ni, Zaizhong; Duan, Huikun; Li, Xiaodan; Wang, Bin; Ma, Xiaofeng; Wei, Qian; Ji, Xiangzhen; Li, Minggang

2016-11-01

Diabetes has been cited as the most challenging health problem in the twenty-first century. Accordingly, it is urgent to develop a new type of efficient and low-toxic antidiabetic medication. Since vanadium compounds have insulin-mimetic and potential hypoglycemic activities for type 1 and type 2 diabetes, a new trend has been developed using vanadium and organic ligands to form a new compound in order to increase the intestinal absorption and reduce the toxicity of vanadium compound. In the current investigation, a new organic vanadium compounds, vanadyl rosiglitazone, was synthesized and determined by infrared spectra. Vanadyl rosiglitazone and three other organic vanadium compounds were administered to the diabetic mice through oral administration for 5 weeks. The results of mouse model test indicated that vanadyl rosiglitazone could regulate the blood glucose level and relieve the symptoms of polydipsia, polyphagia, polyuria, and weight loss without side effects and was more effective than the other three organic vanadium compounds including vanadyl trehalose, vanadyl metformin, and vanadyl quercetin. The study indicated that vanadyl rosiglitazone presents insulin-mimetic activities, and it will be a good potential candidate for the development of a new type of oral drug for type 2 diabetes.

Effects of Vanadium-Containing Compounds on Membrane Lipids and on Microdomains Used in Receptor-Mediated Signaling

PubMed Central

Roess, Deborah A.; Smith, Steven M. L.; Winter, Peter; Zhou, Jun; Dou, Ping; Baruah, Bharat; Trujillo, Alejandro M.; Levinger, Nancy E.; Yang, Xioda; Barisas, B. George; Crans, Debbie C.

2011-01-01

There is increasing evidence for the involvement of plasma membrane microdomains in insulin receptor function. Moreover, disruption of these structures, which are typically enriched in sphingomyelin and cholesterol, results in insulin resistance. Treatment strategies for insulin resistance include the use of vanadium compounds which have been shown in animal models to enhance insulin responsiveness. One possible mechanism for insulin-enhancing effects might involve direct effects of vanadium compounds on membrane lipid organization. These changes in lipid organization promote the partitioning of insulin receptors and other receptors into membrane microdomains where receptors are optimally functional. To explore this possibility, we have used several strategies involving vanadium complexes such as [VO2dipic]− (pyridin-2,6-dicarboxylatodioxovanadium(V)), decavanadate (V10O286−, V10), BMOV (bis(maltolato)oxovanadium(IV)) and [VO(saltris)]2 (2-salicylideniminato-2-(hydroxymethyl)-1,3-dihydroxypropane-oxovanadium(V)). Our strategies include an evaluation of interactions between vanadium-containing compounds and model lipid systems, an evaluation of the effects of vanadium compounds on lipid fluidity in erythrocyte membranes, and studies of the effects of vanadium-containing compounds on signaling events initiated by receptors known to use membrane microdomains as signaling platforms. PMID:18729092

The oxidation of organic additives in the positive vanadium electrolyte and its effect on the performance of vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Nguyen, Tam D.; Whitehead, Adam; Scherer, Günther G.; Wai, Nyunt; Oo, Moe O.; Bhattarai, Arjun; Chandra, Ghimire P.; Xu, Zhichuan J.

2016-12-01

Despite many desirable properties, the vanadium redox flow battery is limited, in the maximum operation temperature that can be continuously endured, before precipitation begins in the positive electrolyte. Many additives have been proposed to improve the thermal stability of the charged positive electrolyte. However, we have found that the apparent stability, revealed in laboratory testing, is often simply an artifact of the test method and arises from the oxidation of the additive, with corresponding partial reduction of V(V) to V(IV). This does not improve the stability of the electrolyte in an operating system. Here, we examined the oxidation of some typical organic additives with carboxyl, alcohol, and multi-functional groups, in sulfuric acid solutions containing V(V). The UV-vis measurements and titration results showed that many compounds reduced the state-of-charge (SOC) of vanadium electrolyte, for example, by 27.8, 88.5, and 81.9% with the addition of 1%wt of EDTA disodium salt, pyrogallol, and ascorbic acid, respectively. The cell cycling also indicated the effect of organic additives on the cell performance, with significant reduction in the usable charge capacity. In addition, a standard screening method for thermally stable additives was introduced, to quickly screen suitable additives for the positive vanadium electrolyte.

Atomic layer deposition of VO2 films with Tetrakis-dimethyl-amino vanadium (IV) as vanadium precursor

NASA Astrophysics Data System (ADS)

Lv, Xinrui; Cao, Yunzhen; Yan, Lu; Li, Ying; Song, Lixin

2017-02-01

VO2 thin films have been grown on Si(100) (VO2/Si) and fused silica substrates (VO2/SiO2) by atomic layer deposition (ALD) using tetrakis-dimethyl-amino vanadium (IV) (TDMAV) as a novel vanadium precursor and water as reactant gas. The quartz crystal microbalance (QCM) measurement was performed to study the ALD process of VO2 thin film deposition, and a constant growth rate of about 0.95 Å/cycle was obtained at the temperature range of 150-200 °C. XRD measurement was performed to study the influence of deposition temperature and post-annealing condition on the crystallization of VO2 films, which indicated that the films deposited between 150 and 200 °C showed well crystallinity after annealing at 475 °C for 100 min in Ar atmosphere. XPS measurement verified that the vanadium oxidation state was 4+ for both as-deposited film and post-annealed VO2/Si film. AFM was applied to study the surface morphology of VO2/Si films, which showed a dense polycrystalline film with roughness of about 1 nm. The resistance of VO2/Si films deposited between 150 °C and 200 °C as a function of temperature showed similar semiconductor-to-metal transition (SMT) characters with the transition temperature for heating branch (Tc,h) of about 72 °C, a hysteresis width of about 10 °C and the resistance change of two orders of magnitude. The increase of Tc,h compared with the bulk VO2 (68 °C) may be attributed to the tensile stress along the c-axis in the film. Transmittance measurement of VO2/SiO2 films showed typical thermochromic property with a NIR switching efficiency of above 50% at 2 μm across the transition.

Convergent acquisition of non-embryonic development in styelid ascidians.

PubMed

Alié, Alexandre; Hiebert, Laurel Sky; Simion, Paul; Scelzo, Marta; Prünster, Maria Mandela; Lotito, Sonia; Delsuc, Frédéric; Douzery, Emmanuel J P; Dantec, Christelle; Lemaire, Patrick; Darras, Sébastien; Kawamura, Kazuo; Brown, Federico D; Tiozzo, Stefano

2018-04-11

Asexual propagation and whole body regeneration are forms of non-embryonic development (NED) widespread across animal phyla and central in life history and evolutionary diversification of metazoans. Whereas it is challenging to reconstruct the gains or losses of NED at large phylogenetic scale, comparative studies could benefit from being conducted at more restricted taxonomic scale, in groups for which phylogenetic relationships are well established. The ascidian family of Styelidae encompasses strictly sexually reproducing solitary forms as well as colonial species that combine sexual reproduction with different forms of NED. To date, the phylogenetic relationships between colonial and solitary styelids remain controversial and so is the pattern of NED evolution. In this study, we built an original pipeline to combine 8 genomes with 18 de novo assembled transcriptomes and constructed datasets of unambiguously orthologous genes. Using a phylogenomic super-matrix of 4,908 genes from these 26 tunicates we provided a robust phylogeny of this family of chordates, which supports two convergent acquisitions of NED. This result prompted us to further describe the budding process in the species Polyandrocarpa zorritensis, leading to the discovery of a novel mechanism of asexual development. While the pipeline and the datasets produced can be used for further phylogenetic reconstructions in tunicates, the phylogeny provided here sets an evolutionary framework for future experimental studies on the emergence and disappearance of complex characters such as asexual propagation and whole body regeneration.

ON THE SEPARATION OF VANADIUM, MOLYBDENUM AND TUNGSTEN BY MEANS OF PAPER CHROMATOGRAPHY. PART I

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

Tzou, S.; Liang, S.

1959-02-01

Molybdenum, tangsten, and vanadium are separated by chromatography as per-acids, and then detected with tannin solution. Of the seven solvents tested, n-butanolhydrogen peroxide-nitric acid mixtures offer the best separations. With the addition of dioxane, the R/sub F/ values of these elements increase, while vanadium and tungsten spots overlap. The formation of per-acids avoids the retainment of tungsten on the original spot and the tailings of vanadium and molybdenum spots. (B.O.G.)

Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

DOEpatents

Epstein, Arthur J.; Morin, Brian G.

1998-01-01

The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors.

Soil-adjusted sorption isotherms for arsenic(V) and vanadium(V)

NASA Astrophysics Data System (ADS)

Rückamp, Daniel; Utermann, Jens; Florian Stange, Claus

2017-04-01

The sorption characteristic of a soil is usually determined by fitting a sorption isotherm model to laboratory data. However, such sorption isotherms are only valid for the studied soil and cannot be transferred to other soils. For this reason, a soil-adjusted sorption isotherm can be calculated by using the data of several soils. Such soil-adjusted sorption isotherms exist for cationic heavy metals, but are lacking for heavy metal oxyanions. Hence, the aim of this study is to establish soil-adjusted sorption isotherms for the oxyanions arsenate (arsenic(V)) and vanadate (vanadium(V)). For the laboratory experiment, 119 soils (samples from top- and subsoils) typical for Germany were chosen. The batch experiments were conducted with six concentrations of arsenic(V) and vanadium(V), respectively. By using the laboratory data, sorption isotherms for each soil were derived. Then, the soil-adjusted sorption isotherms were calculated by non-linear regression of the sorption isotherms with additional soil parameters. The results indicated a correlation between the sorption strength and oxalate-extractable iron, organic carbon, clay, and electrical conductivity for both, arsenic and vanadium. However, organic carbon had a negative regression coefficient. As total organic carbon was correlated with dissolved organic carbon; we attribute this observation to an effect of higher amounts of dissolved organic substances. We conclude that these soil-adjusted sorption isotherms can be used to assess the potential of soils to adsorb arsenic(V) and vanadium(V) without performing time-consuming sorption experiments.

Overview of environmental and occupational vanadium exposure and associated health outcomes: an article based on a presentation at the 8th International Symposium on Vanadium Chemistry, Biological Chemistry, and Toxicology, Washington DC, August 15-18, 2012.

PubMed

Fortoul, T I; Rojas-Lemus, M; Rodriguez-Lara, V; Gonzalez-Villalva, A; Ustarroz-Cano, M; Cano-Gutierrez, G; Gonzalez-Rendon, S E; Montaño, L F; Altamirano-Lozano, M

2014-01-01

Vanadium (V) has a variety of applications that make it suitable for use in ceramic production and decoration, production of pigments for a variety of products, an accelerator for drying paint, production of aniline black dye, and as a mordant in coloring textiles. Taking advantage of its hardness, resilience, ability to form alloys, and its resistance to corrosion, V is also used in the production of tools, steel, machinery, and surgical implants. V is employed in producing photographic developers, batteries, and semi-conductors, and in catalyst-based recycling processes. As technologies have evolved, the use of V has increased in jet aircraft and space technology, as well as in manufacture of ultraviolet filter glass to prevent radiation injury. Due to these myriad uses, the potential for occupational exposure to V is ever-evident. Similarly, there is an increased risk for environmental contamination by V agents themselves or as components of by-products released into the environment. For example, the use of V in sulfuric acid production results in the release of soot and/or fly ash rich in vanadium pentoxide. Petroleum refinery, smelting, welding, and cutting of V-rich steel alloy, the cleaning and repair of oil-fired boilers, and catalysis of chemical productions are other sources of increased airborne V-bearing particles in local/distant environments. Exposure of non-workers to V is an increasing health concern. Studies have demonstrated associations between exposure to airborne V-bearing particles (as part of air pollution) and increased risks of a variety of pathologies like hypertension, dysrhythmia, systemic inflammation, hyper-coagulation, cancers, and bronchial hyper-reactivity. This paper will provide a review of the history of V usage in occupational settings, documented exposure levels, environmental levels of V associated with pollution, epidemiologic data relating V exposure(s) to adverse health outcomes, and governmental responses to protect both

Removal of arsenic, vanadium and/or nickel compounds from spent catecholated polymer

DOEpatents

Fish, R.H.

1987-04-21

Described is a process for removing arsenic, vanadium, and/or nickel from petroliferous derived liquids by contacting said liquid at an elevated temperature with a divinylbenzene-crosslinked polystyrene having catechol ligands anchored thereon. For vanadium and nickel removal an amine, preferably a diamine is included. Also, described is a process for regenerating spent catecholated polystyrene by removal of the arsenic, vanadium, and/or nickel bound to it from contacting petroliferous liquid as described above and involves: treating the spent polymer containing any vanadium and/or nickel with an aqueous acid to achieve an acid pH; and, separating the solids from the liquid; and then treating said spent catecholated polystyrene, at a temperature in the range of about 20 to 100 C with an aqueous solution of at least one carbonate and/or bicarbonate of ammonium, alkali and alkaline earth metals, said solution having a pH between about 8 and 10; and, separating the solids and liquids from each other. Preferably the regeneration treatment of arsenic containing catecholated polymer is in two steps wherein the first step is carried out with an aqueous alcoholic carbonate solution containing lower alkyl alcohol, and, the steps are repeated using a bicarbonate.

Electrical and Infrared Optical Properties of Vanadium Oxide Semiconducting Thin-Film Thermometers

NASA Astrophysics Data System (ADS)

Zia, Muhammad Fakhar; Abdel-Rahman, Mohamed; Alduraibi, Mohammad; Ilahi, Bouraoui; Awad, Ehab; Majzoub, Sohaib

2017-10-01

A synthesis method has been developed for preparation of vanadium oxide thermometer thin film for microbolometer application. The structure presented is a 95-nm thin film prepared by sputter-depositing nine alternating multilayer thin films of vanadium pentoxide (V2O5) with thickness of 15 nm and vanadium with thickness of 5 nm followed by postdeposition annealing at 300°C in nitrogen (N2) and oxygen (O2) atmospheres. The resulting vanadium oxide (V x O y ) thermometer thin films exhibited temperature coefficient of resistance (TCR) of -3.55%/°C with room-temperature resistivity of 2.68 Ω cm for structures annealed in N2 atmosphere, and TCR of -3.06%/°C with room-temperature resistivity of 0.84 Ω cm for structures annealed in O2 atmosphere. Furthermore, optical measurements of N2- and O2-annealed samples were performed by Fourier-transform infrared ellipsometry to determine their dispersion curves, refractive index ( n), and extinction coefficient ( k) at wavelength from 7000 nm to 14,000 nm. The results indicate the possibility of applying the developed materials in thermometers for microbolometers.

Vanadium release in whole blood, serum and urine of patients implanted with a titanium alloy hip prosthesis.

PubMed

Catalani, S; Stea, S; Beraudi, A; Gilberti, M E; Bordini, B; Toni, A; Apostoli, P

2013-08-01

Vanadium (V) is a minor constituent of the Titanium-Aluminum-Vanadium (TiAlV) alloy currently used in cementless hip prostheses. Present study aimed at verifying the correlation of vanadium levels among different matrices and assessing reference levels of the ion in a population of patients wearing a well-functioning hip prosthesis. Vanadium was measured using Inductive Coupled Plasma Mass Spectrometry (ICP-MS) in whole blood, serum and urine of 129 patients implanted with a TiAlV-alloy hip prosthesis. The values in the serum were above the upper limit of the reference values in 42% of patients (29% in urine and 13% in whole blood). A good correlation among matrices was observed (p < 0.001). The cohort of patients (N = 32) complaining of pain or in which a loosening or damage to the prosthesis was assessed showed a significantly higher excretion of vanadium in urine as compared with the remaining asymptomatic patients (p = 0.001). The 95th percentile distribution of vanadium in the cohort of patients with a well-functioning prosthesis was 0.3 μg/L in whole blood, 0.5 μg/L in serum and 2.8 μg/L in urine, higher that in the unexposed population, especially for urine. The presence of a prosthesis, even though well-functioning, may cause a possible release of vanadium into the blood and a significant urinary excretion. The reference values of vanadium of the asymptomatic patients with titanium alloy hip prostheses supplied information regarding the background exposure level of the ions and their lower and upper limits.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.30 Applicability; description of the...

Odontonia plurellicola sp. n. and Odontonia bagginsi sp. n., two new ascidian-associated shrimp from Ternate and Tidore, Indonesia, with a phylogenetic reconstruction of the genus (Crustacea, Decapoda, Palaemonidae)

PubMed Central

de Gier, Werner; Fransen, Charles H.J.M.

2018-01-01

Abstract Two new species of palaemonid shrimp associated with ascidian hosts, Odontonia bagginsi sp. n. from Tidore and Odontonia plurellicola sp. n., from Ternate, Indonesia are described and figured. Through phylogenetic analyses based on both morphological and molecular datasets (mitochondrial Cytochrome c oxidase subunit I gene and the 16S mitochondrial ribosomal gene) of the genus Odontonia, the phylogenetic positions of the new species have been reconstructed. Scanning Electron Microscopy has been used to observe additional characters on dactyli of the ambulatory pereiopods. Odontonia plurellicola sp. n. appears to be more closely related to O. simplicipes and O. seychellensis, but it differs most notably in the morphology of the rostrum and mouthparts. Odontonia plurellicola sp. n. appears to be the only Odontonia species living inside a phlebobranch ascidian Plurella sp. Odontonia bagginsi sp. n. is closely related to O. sibogae, but differs markedly in the abundance of setae on the propodi of the ambulatory pereiopods. In the present paper, O. maldivensis Fransen, 2006 is regarded as a junior synonym of O. rufopunctata Fransen, 2002 based on both morphological and molecular aspects. PMID:29910665

One-step hydrothermal synthesis of hexangular starfruit-like vanadium oxide for high power aqueous supercapacitors

NASA Astrophysics Data System (ADS)

Shao, Jie; Li, Xinyong; Qu, Qunting; Zheng, Honghe

2012-12-01

Homogenous hexangular starfruit-like vanadium oxide was prepared for the first time by a one-step hydrothermal method. The assembly process of hexangular starfruit-like structure was observed from TEM images. The electrochemical performance of starfruit-like vanadium oxide was examined by cyclic voltammetry and galvanostatic charge/discharge. The obtained starfruit-like vanadium oxide exhibits a high power capability (19 Wh kg-1 at the specific power of 3.4 kW kg-1) and good cycling stability for supercapacitors application.

Removal and recovery of vanadium from alkaline steel slag leachates with anion exchange resins.

PubMed

Gomes, Helena I; Jones, Ashley; Rogerson, Mike; Greenway, Gillian M; Lisbona, Diego Fernandez; Burke, Ian T; Mayes, William M

2017-02-01

Leachable vanadium (V) from steel production residues poses a potential environmental hazard due to its mobility and toxicity under the highly alkaline pH conditions that characterise these leachates. This work aims to test the efficiency of anion exchange resins for vanadium removal and recovery from steel slag leachates at a representative average pH of 11.5. Kinetic studies were performed to understand the vanadium sorption process. The sorption kinetics were consistent with a pseudo-first order kinetic model. The isotherm data cannot differentiate between the Langmuir and Freundlich models. The maximum adsorption capacity (Langmuir value q max ) was 27 mg V g -1 resin. In column anion exchange, breakthrough was only 14% of the influent concentration after passing 90 L of steel slag leachate with 2 mg L -1 V through the column. When eluting the column 57-72% of vanadium was recovered from the resin with 2 M NaOH. Trials on the reuse of the anion exchange resin showed it could be reused 20 times without loss of efficacy, and on average 69% of V was recovered during regeneration. The results document for the first time the use of anion exchange resins to remove vanadium from steel slag leachate. As an environmental contaminant, removal of V from leachates may be an obligation for long-term management requirements of steel slag repositories. Vanadium removal coupled with the recovery can potentially be used to offset long-term legacy treatment costs. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

DOEpatents

Epstein, A.J.; Morin, B.G.

1998-10-13

The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors. 21 figs.

Interactions of Penicillium griseofulvum with inorganic and organic substrates: vanadium, lead and hexachlorocyclohexane

NASA Astrophysics Data System (ADS)

Ceci, Andrea; Pierro, Lucia; Riccardi, Carmela; Maggi, Oriana; Pinzari, Flavia; Gadd, Geoffrey Michael; Petrangeli Papini, Marco; Persiani, Anna Maria

2015-04-01

Soil is an essential and non-renewable resource for human beings and ecosystems. In recent years, anthropogenic activities mainly related to hydrocarbon fuel combustion, mining and industrial activities have increased the levels of vanadium in the environment, raising concern over its spread. Vanadium may be essential for some bacteria and fungi, but can have toxic effects at high concentrations. The pesticide lindane or γ-hexachlorocyclohexane (γ-HCH) and another two isomers of hexachlorocyclohexane (HCH), α-HCH, and β-HCH, were included as persistent organic pollutants in the Stockholm Convention in 2008, and their worldwide spread and toxic effects on organisms are severe environmental problems. Fungi play important roles in soil and can survive in high concentrations of toxic elements and pesticides by possessing mechanisms for the degradation, utilization and transformation of organic and inorganic substrates. The transformation of potentially toxic elements (PTEs), and degradation of chlorinated pesticides and other persistent organic pollutants may provide environmentally-friendly and economical approaches for environmental management and restoration. In this work, we have investigated the tolerance of a soil fungal species, Penicillum griseofulvum, to different hexachlorocyclohexane (HCH) isomers, α-HCH, β-HCH, δ-HCH and γ-HCH or lindane, and two PTEs, vanadium and lead in relation to growth responses and biotransformation. P. griseofulvum was isolated from soils with high levels of PTEs (including vanadium and lead), and HCH residues. P. griseofulvum was able to tolerate vanadium concentrations up to 5 mM, combinations of 2.5 mM vanadium and lead compounds, and was able to grow in the presence of a 4 mg L-1 mixture of α-HCH, β-HCH, δ-HCH and γ-HCH, and degrade these substrates. Tolerance mechanisms may explain the occurrence of fungi in polluted habitats: their roles in the biotransformation of metals and persistent organic pollutants may

Investigating the air oxidation of V(II) ions in a vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Ngamsai, Kittima; Arpornwichanop, Amornchai

2015-11-01

The air oxidation of vanadium (V(II)) ions in a negative electrolyte reservoir is a major side reaction in a vanadium redox flow battery (VRB), which leads to electrolyte imbalance and self-discharge of the system during long-term operation. In this study, an 80% charged negative electrolyte solution is employed to investigate the mechanism and influential factors of the reaction in a negative-electrolyte reservoir. The results show that the air oxidation of V(II) ions occurs at the air-electrolyte solution interface area and leads to a concentration gradient of vanadium ions in the electrolyte solution and to the diffusion of V(II) and V(III) ions. The effect of the ratio of the electrolyte volume to the air-electrolyte solution interface area and the concentrations of vanadium and sulfuric acid in an electrolyte solution is investigated. A higher ratio of electrolyte volume to the air-electrolyte solution interface area results in a slower oxidation reaction rate. The high concentrations of vanadium and sulfuric acid solution also retard the air oxidation of V(II) ions. This information can be utilized to design an appropriate electrolyte reservoir for the VRB system and to prepare suitable ingredients for the electrolyte solution.

Doping of vanadium to nanocrystalline diamond films by hot filament chemical vapor deposition

PubMed Central

2012-01-01

Doping an impure element with a larger atomic volume into crystalline structure of buck crystals is normally blocked because the rigid crystalline structure could not tolerate a larger distortion. However, this difficulty may be weakened for nanocrystalline structures. Diamonds, as well as many semiconductors, have a difficulty in effective doping. Theoretical calculations carried out by DFT indicate that vanadium (V) is a dopant element for the n-type diamond semiconductor, and their several donor state levels are distributed between the conduction band and middle bandgap position in the V-doped band structure of diamond. Experimental investigation of doping vanadium into nanocrystalline diamond films (NDFs) was first attempted by hot filament chemical vapor deposition technique. Acetone/H2 gas mixtures and vanadium oxytripropoxide (VO(OCH2CH2CH3)3) solutions of acetone with V and C elemental ratios of 1:5,000, 1:2,000, and 1:1,000 were used as carbon and vanadium sources, respectively. The resistivity of the V-doped NDFs decreased two orders with the increasing V/C ratios. PMID:22873631

Metal Insulator transition in Vanadium Dioxide

NASA Astrophysics Data System (ADS)

Jovaini, Azita; Fujita, Shigeji; Suzuki, Akira; Godoy, Salvador

2012-02-01

MAR12-2011-000262 Abstract Submitted for the MAR12 Meeting of The American Physical Society Sorting Category: 03.9 (T) On the metal-insulator-transition in vanadium dioxide AZITA JOVAINI, SHIGEJI FUJITA, University at Buffalo, SALVADOR GODOY, UNAM, AKIRA SUZUKI, Tokyo University of Science --- Vanadium dioxide (VO2) undergoes a metal-insulator transition (MIT) at 340 K with the structural change from tetragonal to monoclinic crystal. The conductivity _/ drops at MIT by four orders of magnitude. The low temperature monoclinic phase is known to have a lower ground-state energy. The existence of the k-vector k is prerequisite for the conduction since the k appears in the semiclassical equation of motion for the conduction electron (wave packet). The tetragonal (VO2)3 unit is periodic along the crystal's x-, y-, and z-axes, and hence there is a three-dimensional k-vector. There is a one-dimensional k for a monoclinic crystal. We believe this difference in the dimensionality of the k-vector is the cause of the conductivity drop. Prefer Oral Session X Prefer .

Graphene-modified nanostructured vanadium pentoxide hybrids with extraordinary electrochemical performance for Li-ion batteries

DOE PAGES

Liu, Qi; Li, Zhe-Fei; Liu, Yadong; ...

2015-01-20

The long-standing issues of low intrinsic electronic conductivity, slow lithium-ion diffusion and irreversible phase transitions on deep discharge prevent the high specific capacity/energy (443 mAh g -1 and 1,550 Wh kg -1) vanadium pentoxide from being used as the cathode material in practical battery applications. Here we develop a method to incorporate graphene sheets into vanadium pentoxide nanoribbons via the sol–gel process. The resulting graphene-modified nanostructured vanadium pentoxide hybrids contain only 2 wt. % graphene, yet exhibits extraordinary electrochemical performance: a specific capacity of 438 mAh g -1, approaching the theoretical value (443 mAh g -1), a long cyclability andmore » significantly enhanced rate capability. Such performance is the result of the combined effects of the graphene on structural stability, electronic conduction, vanadium redox reaction and lithium-ion diffusion supported by various experimental studies. Finally, this method provides a new avenue to create nanostructured metal oxide/graphene materials for advanced battery applications.« less

Imaging metal-like monoclinic phase stabilized by surface coordination effect in vanadium dioxide nanobeam

PubMed Central

Li, Zejun; Wu, Jiajing; Hu, Zhenpeng; Lin, Yue; Chen, Qi; Guo, Yuqiao; Liu, Yuhua; Zhao, Yingcheng; Peng, Jing; Chu, Wangsheng; Wu, Changzheng; Xie, Yi

2017-01-01

In correlated systems, intermediate states usually appear transiently across phase transitions even at the femtosecond scale. It therefore remains an open question how to determine these intermediate states—a critical issue for understanding the origin of their correlated behaviour. Here we report a surface coordination route to successfully stabilize and directly image an intermediate state in the metal-insulator transition of vanadium dioxide. As a prototype metal-insulator transition material, we capture an unusual metal-like monoclinic phase at room temperature that has long been predicted. Coordinate bonding of L-ascorbic acid molecules with vanadium dioxide nanobeams induces charge-carrier density reorganization and stabilizes metallic monoclinic vanadium dioxide, unravelling orbital-selective Mott correlation for gap opening of the vanadium dioxide metal–insulator transition. Our study contributes to completing phase-evolution pathways in the metal-insulator transition process, and we anticipate that coordination chemistry may be a powerful tool for engineering properties of low-dimensional correlated solids. PMID:28613281

Lactational Vitamin E Protects Against the Histotoxic Effects of Systemically Administered Vanadium in Neonatal Rats.

PubMed

Olaolorun, F A; Obasa, A A; Balogun, H A; Aina, O O; Olopade, J O

2014-12-29

The work investigated the protective role of lactational vitamin E administration on vanadium-induced histotoxicity. Three groups of Wistar rats, with each group comprising of two dams and their pups, were used in this study. Group I pups were administered intraperitoneal injection of sterile water at volumes corresponding to the dose rate of the vanadium (sodium metavanadate) treated group from postnatal day (PND) 1-14 while those in Group II were administered intraperitoneal injection of 3mg/kg vanadium from PND 1-14. Group III pups were administered intraperitoneal injection of 3mg/kg vanadium while the dam received oral vitamin E (500 mg) concurrently every 72 hours. The results showed that group II pups exhibited histopathological changes which included seminiferous tubule disruption of the testes characterised by vacuolar degeneration and coagulative necrosis of spermatogonia and Sertoli cells with reduction in mitosis, and areas of interstitial thickening with fibroblast proliferation. In addition, the lungs showed disruption of the bronchiolar wall and denudation of the bronchiolar respiratory epithelium while the liver showed hydropic degeneration and coagulative necrosis of the centrilobular hepatocytes. These histotoxic changes were ameliorated in the vanadium + vitamin E group. We conclude that lactational vitamin E protects against the histotoxic effects of vanadium and could be a consideration for supplementation in the occupationally and environmentally exposed neonates. However, caution should be taken in vitamin E supplementation because there is still equivocal evidence surrounding its benefits as a supplement at the moment.

Vanadium sorption by mineral soils: Development of a predictive model.

PubMed

Larsson, Maja A; Hadialhejazi, Golshid; Gustafsson, Jon Petter

2017-02-01

The toxicity of vanadium in soils depends on its sorption to soil components. Here we studied the vanadate(V) sorption properties of 26 mineral soils. The data were used to optimise parameters for a Freundlich equation with a pH term. Vanadium K-edge XANES spectroscopy for three selected soils confirmed that the added vanadate(V) had accumulated mostly as adsorbed vanadate(V) on Fe and Al hydrous oxides, with only minor contributions from organically complexed vanadium(IV). Data on pH-dependent V solubility for seven soils showed that on average 0.36 H + accompanied each V during adsorption and desorption. The resulting model provided reasonable fits to the V sorption data, with r 2  > 0.99 for 20 of 26 soils. The observed K dS value, i.e. the ratio of total to dissolved V, was strongly dependent on V addition and soil; it varied between 3 and 4 orders of magnitude. The model was used to calculate the Freundlich sorption strength (FSS), i.e. the amount of V sorbed at [V] = 2.5 mg L -1 , in the concentration range of observed plant toxicities. A close relationship between FSS and oxalate-extractable Fe and Al was found (r 2  = 0.85) when one acidic soil was removed from the regression. The FSS varied between 27 and 8718 mg V kg -1 , showing that the current environmental guidelines can be both under- and overprotective for vanadium. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structural and thermal properties of vanadium tellurite glasses

NASA Astrophysics Data System (ADS)

Kaur, Rajinder; Kaur, Ramandeep; Khanna, Atul; González, Fernando

2018-04-01

V2O5-TeO2 glasses containing 10 to 50 mol% V2O5 were prepared by melt quenching and characterized by X-ray diffraction (XRD), density, Differential Scanning Calorimetry (DSC) and Raman studies.XRD confirmed the amorphous nature of vanadium tellurite samples. The density of the glasses decreases and the molar volume increases on increasing the concentration of V2O5. The thermal properties, such as glass transition temperature Tg, crystallization temperature Tc, and the melting temperature Tm were measured. Tg decreases from a value of 288°C to 232°C. The changes in Tg were correlated with the number of bonds per unit volume, and the average stretching force constant. Raman spectra were used to elucidate the short-range structure of vanadium tellurite glasses.

Sulfonated graphene oxide/nafion composite membrane for vanadium redox flow battery.

PubMed

Kim, Byung Guk; Han, Tae Hee; Cho, Chang Gi

2014-12-01

Nafion is the most frequently used as the membrane material due to its good proton conductivity, and excellent chemical and mechanical stabilities. But it is known to have poor barrier property due to its well-developed water channels. In order to overcome this drawback, graphene oxide (GO) derivatives were introduced for Nafion composite membranes. Sulfonated graphene oxide (sGO) was prepared from GO. Both sGO and GO were treated each with phenyl isocyanate and transformed into corresponding isGO and iGO in order to promote miscibility with Nafion. Then composite membranes were obtained, and the adaptability as a membrane for vanadium redox flow battery (VRFB) was investigated in terms of proton conductivity and vanadium permeability. Compared to a pristine Nafion, proton conductivities of both isGO/Nafion and iGO/Nafion membranes showed less temperature sensitivity. Both membranes also showed quite lower vanadium permeability at room temperature. Selectivity of the membrane was the highest for isGO/Nafion and the lowest for the pristine Nafion.

Measurements of Anisotropy in Non-LTE Low-Density, Iron-Vanadium Plasmas

NASA Astrophysics Data System (ADS)

Jarrott, L. C.; Foord, M. E.; Heeter, R. F.; Liedahl, D. A.; Barrios, M. A.; Brown, G. V.; Gray, W.; Marley, E. V.; Mauche, C. W.; Widmann, K.; Schneider, M. B.

2016-10-01

We report on Non-LTE anisotropy experiments carried out on the Omega Laser Facility at the Laboratory for Laser Energetics, Rochester NY. In these experiments, a 50/50 mixture of iron and vanadium, 2000A thick and 250um in diameter is contained within a beryllium tamper, 10um thick and 1000um in diameter. Each side of the beryllium tamper is then irradiated using 52 of the 60 Omega beams with an intensity of 3e14 W/cm2 over 3ns in duration. Iron-Vanadium line ratios indicate a plasma temperature of greater than 2 keV was produced. The geometrical aspect ratio ranged from 0.8 to 4.0; allowing for the characterization of optical-depth-dependent anisotropy in the iron-vanadium line emission. Results of this characterization and its comparison with modeling will be presented. This work performed under the auspices of U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

In situ self-sacrificed template synthesis of vanadium nitride/nitrogen-doped graphene nanocomposites for electrochemical capacitors.

PubMed

Liu, Hong-Hui; Zhang, Hong-Ling; Xu, Hong-Bin; Lou, Tai-Ping; Sui, Zhi-Tong; Zhang, Yi

2018-03-15

Vanadium nitride and graphene have been widely used as pseudo-capacitive and electric double-layer capacitor electrode materials for electrochemical capacitors, respectively. However, the poor cycling stability of vanadium nitride and the low capacitance of graphene impeded their practical applications. Herein, we demonstrated an in situ self-sacrificed template method for the synthesis of vanadium nitride/nitrogen-doped graphene (VN/NGr) nanocomposites by the pyrolysis of a mixture of dicyandiamide, glucose, and NH 4 VO 3 . Vanadium nitride nanoparticles of the size in the range of 2 to 7 nm were uniformly embedded into the nitrogen-doped graphene skeleton. Furthermore, the VN/NGr nanocomposites with a high specific surface area and pore volume showed a high specific capacitance of 255 F g -1 at 10 mV s -1 , and an excellent cycling stability (94% capacitance retention after 2000 cycles). The excellent capacitive properties were ascribed to the excellent conductivity of nitrogen-doped graphene, high surface area, high pore volume, and the synergistic effect between vanadium nitride and nitrogen-doped graphene.

Reduction of Vanadium Oxide (VOx) under High Vacuum Conditions as Investigated by X-Ray Photoelectron Spectroscopy

NASA Astrophysics Data System (ADS)

Chourasia, A.

2015-03-01

Vanadium oxide thin films were formed by depositing thin films of vanadium on quartz substrates and oxidizing them in an atmosphere of oxygen. The deposition was done by the e-beam technique. The oxide films were annealed at different temperatures for different times under high vacuum conditions. The technique of x-ray photoelectron spectroscopy has been employed to study the changes in the oxidation states of vanadium and oxygen in such films. The spectral features in the vanadium 2p, oxygen 1s, and the x-ray excited Auger regions were investigated. The Auger parameter has been utilized to study the changes. The complete oxidation of elemental vanadium to V2O5 was observed to occur at 700°C. At any other temperature, a mixture of oxides consisting of V2O5 and VO2 was observed in the films. Annealing of the films resulted in the gradual loss of oxygen followed by reduction in the oxidation state from +5 to 0. The reduction was observed to depend upon the annealing temperature and the annealing time. Organized Research, TAMU-Commerce.

Elucidating the Higher Stability of Vanadium (V) Cations in Mixed Acid Based Redox Flow Battery Electrolytes

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

Vijayakumar, M.; Wang, Wei; Nie, Zimin

2013-11-01

The Vanadium (V) cation structures in mixed acid based electrolyte solution were analysed by density functional theory (DFT) based computational modelling and 51V and 35Cl Nuclear Magnetic Resonance (NMR) spectroscopy. The Vanadium (V) cation exists as di-nuclear [V2O3Cl2.6H2O]2+ compound at higher vanadium concentrations (≥1.75M). In particular, at high temperatures (>295K) this di-nuclear compound undergoes ligand exchange process with nearby solvent chlorine molecule and forms chlorine bonded [V2O3Cl2.6H2O]2+ compound. This chlorine bonded [V2O3Cl2.6H2O]2+ compound might be resistant to the de-protonation reaction which is the initial step in the precipitation reaction in Vanadium based electrolyte solutions. The combined theoretical and experimental approachmore » reveals that formation of chlorine bonded [V2O3Cl2.6H2O]2+ compound might be central to the observed higher thermal stability of mixed acid based Vanadium (V) electrolyte solutions.« less

Removal of arsenic, vanadium and/or nickel compounds from spent catecholated polymer

DOEpatents

Fish, Richard H.

1987-01-01

Described is a process for removing arsenic, vanadium, and/or nickel from petroliferous derived liquids by contacting said liquid at an elevated temperature with a divinylbenzene-crosslinked polystyrene having catechol ligands anchored thereon. For vanadium and nickel removal an amine, preferably a diamine is included. Also, described is a process for regenerating spent catecholated polystyrene by removal of the arsenic, vanadium, and/or nickel bound to it from contacting petroliferous liquid as described above and involves: treating the spent polymer containing any vanadium and/or nickel with an aqueous acid to achieve an acid pH; and, separating the solids from the liquid; and then treating said spent catecholated polystyrene, at a temperature in the range of about 20.degree. to 100.degree. C. with an aqueous solution of at least one carbonate and/or bicarbonate of ammonium, alkali and alkaline earth metals, said solution having a pH between about 8 and 10; and, separating the solids and liquids from each other. Preferably the regeneration treatment of arsenic containing catecholated polymer is in two steps wherein the first step is carried out with an aqueous alcoholic carbonate solution containing lower alkyl alcohol, and, the steps are repeated using a bicarbonate.

Anticancer effects of brominated indole alkaloid Eudistomin H from marine ascidian Eudistoma viride against cervical cancer cells (HeLa).

PubMed

Rajesh, Rajaian Pushpabai; Annappan, Murugan

2015-01-01

Marine invertebrates called ascidians are prolific producers of bioactive substances. The ascidian Eudistoma viride, distributed along the Southeast coast of India, was investigated for its in vitro cytotoxic activity against human cervical carcinoma (HeLa) cells by the MTT assay. The crude methanolic extract of E. viride, with an IC50 of 53 μg/ml, was dose-dependently cytotoxic. It was more potent at 100 μg/ml than cyclohexamide (1 μg/ml), reducing cell viability to 9.2%. Among nine fractions separated by chromatography, ECF-8 exhibited prominent cytoxic activity at 10 μg/ml. The HPLC fraction EHF-21 of ECF-8 was remarkably dose- and time-dependently cytotoxic, with 39.8% viable cells at 1 μg/ml compared to 51% in cyclohexamide-treated cells at the same concentration; the IC50 was 0.49 μg/ml. Hoechst staining of HeLa cells treated with EHF-21 at 0.5 μg/ml revealed apoptotic events such an cell shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies. Cell size and granularity study showed changes in light scatter, indicating the characteristic feature of cells dying by apoptosis. The cell-cycle analysis of HeLa cells treated with fraction EHF-21 at 1 μg/ml showed the marked arrest of cells in G0/G1, S and G2/M phases and an increase in the sub G0/G1 population indicated an increase in the apoptotic cell population. The statistical analysis of the sub-G1 region showed a dose-dependent induction of apoptosis. DNA fragmentation was also observed in HeLa cells treated with EHF-21. The active EHF-21 fraction, a brominated indole alkaloid Eudistomin H, led to apoptotic death of HeLa cells. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Detailed mineral and chemical relations in two uranium-vanadium ores

USGS Publications Warehouse

Garrels, Robert M.; Larsen, E. S.; Pommer, A.M.; Coleman, R.G.

1956-01-01

Channel samples from two mines on the Colorado Plateau have been studied in detail both mineralogically and chemically. A channel sample from the Mineral Joe No. 1 mine, Montrose County, Colo., extends from unmineralized rock on one side, through a zone of variable mineralization, into only weakly mineralized rock. The unmineralized rock is a fairly clean quartz sand cemented with gypsum and contains only minor amounts of clay minerals. One boundary between unmineralized and mineralized rock is quite sharo and is nearly at right angles to the bedding. Vanadium clay minerals, chiefly mixed layered mica-montmorillonite and chlorite-monmorillonite, are abundant throughout the mineralized zone. Except in the dark "eye" of the channel sample, the vanadium clay minerals are accompanied by hewettite, carnotite, tyuyamunite, and probably unidentified vanadates. In the dark "eye," paramontroseite, pyrite, and marcasite are abundant, and bordered on each side by a zone containing abundant corvusite. No recognizable uranium minerals were seen in the paramontroseite zone although uranium is abundant there. Coaly material is recognizable throughout all of the channel but is most abundant in and near the dark "eye." Detailed chemical studies show a general increase in Fe, Al, U, and V, and a decrease in SO4 toward the "eye" of the channel. Reducing capacity studies indicate that V(IV) and Fe(II) are present in the clay mineral throughout the channel, but only in and near the "eye" are other V(IV) minerals present (paramontroseite and corvusite). The uranium is sexivalent, although its state of combination is conjectural where it is associated with paramontroseite. Where the ore boundary is sharp, the boundary of introduced trace elements is equally sharp. Textural and chemical relations leave no doubt that the "eye: is a partially oxidized remnant of a former lower-valence ore, and the remainder of the channel is a much more fully oxidized remnant. A channel sample from the

Assessment of total and organic vanadium levels and their bioaccumulation in edible sea cucumbers: tissues distribution, inter-species-specific, locational differences and seasonal variations.

PubMed

Liu, Yanjun; Zhou, Qingxin; Xu, Jie; Xue, Yong; Liu, Xiaofang; Wang, Jingfeng; Xue, Changhu

2016-02-01

The objective of this study is to investigate the levels, inter-species-specific, locational differences and seasonal variations of vanadium in sea cucumbers and to validate further several potential factors controlling the distribution of metals in sea cucumbers. Vanadium levels were evaluated in samples of edible sea cucumbers and were demonstrated exhibit differences in different seasons, species and sampling sites. High vanadium concentrations were measured in the sea cucumbers, and all of the vanadium detected was in an organic form. Mean vanadium concentrations were considerably higher in the blood (sea cucumber) than in the other studied tissues. The highest concentration of vanadium (2.56 μg g(-1)), as well as a higher degree of organic vanadium (85.5 %), was observed in the Holothuria scabra samples compared with all other samples. Vanadium levels in Apostichopus japonicus from Bohai Bay and Yellow Sea have marked seasonal variations. Average values of 1.09 μg g(-1) of total vanadium and 0.79 μg g(-1) of organic vanadium were obtained in various species of sea cucumbers. Significant positive correlations between vanadium in the seawater and V org in the sea cucumber (r = 81.67 %, p = 0.00), as well as between vanadium in the sediment and V org in the sea cucumber (r = 77.98 %, p = 0.00), were observed. Vanadium concentrations depend on the seasons (salinity, temperature), species, sampling sites and seawater environment (seawater, sediment). Given the adverse toxicological effects of inorganic vanadium and positive roles in controlling the development of diabetes in humans, a regular monitoring programme of vanadium content in edible sea cucumbers can be recommended.

HSQC-TOCSY Fingerprinting-Directed Discovery of Antiplasmodial Polyketides from the Marine Ascidian-Derived Streptomyces sp. (USC-16018).

PubMed

Buedenbender, Larissa; Robertson, Luke P; Lucantoni, Leonardo; Avery, Vicky M; Kurtböke, D İpek; Carroll, Anthony R

2018-05-30

Chemical investigations on the fermentation extract obtained from an ascidian-derived Streptomyces sp. (USC-16018) yielded a new ansamycin polyketide, herbimycin G ( 1 ), as well as a known macrocyclic polyketide, elaiophylin ( 2 ), and four known diketopiperazines ( 3 ⁻ 6 ). The structures of the compounds were elucidated based on 1D/2D NMR and MS data. The absolute configuration of 1 was established by comparison of experimental and predicted electronic circular dichroism (ECD) data. Antiplasmodial activities were tested for the natural products against chloroquine sensitive (3D7) and chloroquine resistant (Dd2) Plasmodium falciparum strains; the two polyketides ( 1 ⁻ 2 ) demonstrated an inhibition of >75% against both parasite strains and while 2 was highly cytotoxic, herbimycin G ( 1 ) showed no cytotoxicity and good predicted water solubility.

Method to remove uranium/vanadium contamination from groundwater

DOEpatents

Metzler, Donald R.; Morrison, Stanley

2004-07-27

A process for removing uranium/vanadium-based contaminants from groundwater using a primary in-ground treatment media and a pretreatment media that chemically adjusts the groundwater contaminant to provide for optimum treatment by the primary treatment media.

Novel catalytic effects of Mn3O4 for all vanadium redox flow batteries.

PubMed

Kim, Ki Jae; Park, Min-Sik; Kim, Jae-Hun; Hwang, Uk; Lee, Nam Jin; Jeong, Goojin; Kim, Young-Jun

2012-06-04

A new approach for enhancing the electrochemical performance of carbon felt electrodes by employing non-precious metal oxides is designed. The outstanding electro-catalytic activity and mechanical stability of Mn(3)O(4) are advantageous in facilitating the redox reaction of vanadium ions, leading to efficient operation of a vanadium redox flow battery.

Design, Synthesis and Pharmacological Evaluation of Novel Vanadium-Containing Complexes as Antidiabetic Agents

PubMed Central

Fedorova, Elena V.; Buryakina, Anna V.; Zakharov, Alexey V.; Filimonov, Dmitry A.; Lagunin, Alexey A.; Poroikov, Vladimir V.

2014-01-01

Based on the data about structure and antidiabetic activity of twenty seven vanadium and zinc coordination complexes collected from literature we developed QSAR models using the GUSAR program. These QSAR models were applied to 10 novel vanadium coordination complexes designed in silico in order to predict their hypoglycemic action. The five most promising substances with predicted potent hypoglycemic action were selected for chemical synthesis and pharmacological evaluation. The selected coordination vanadium complexes were synthesized and tested in vitro and in vivo for their hypoglycemic activities and acute rat toxicity. Estimation of acute rat toxicity of these five vanadium complexes was performed using a freely available web-resource (http://way2drug.com/GUSAR/acutoxpredict.html). It has shown that the selected compounds belong to the class of moderate toxic pharmaceutical agents, according to the scale of Hodge and Sterner. Comparison with the predicted data has demonstrated a reasonable correspondence between the experimental and predicted values of hypoglycemic activity and toxicity. Bis{tert-butyl[amino(imino)methyl]carbamato}oxovanadium (IV) and sodium(2,2′-Bipyridyl)oxo-diperoxovanadate(V) octahydrate were identified as the most potent hypoglycemic agents among the synthesized compounds. PMID:25057899

3. INTERIOR, SOUTHEAST VIEW. Vanadium Corporation of America (VCA) ...

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

3. INTERIOR, SOUTHEAST VIEW. - Vanadium Corporation of America (VCA) Naturita Mill, Grinding Rod Mill, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

A mixed acid based vanadium-cerium redox flow battery with a zero-gap serpentine architecture

NASA Astrophysics Data System (ADS)

Leung, P. K.; Mohamed, M. R.; Shah, A. A.; Xu, Q.; Conde-Duran, M. B.

2015-01-01

This paper presents the performance of a vanadium-cerium redox flow battery using conventional and zero-gap serpentine architectures. Mixed-acid solutions based on methanesulfonate-sulfate anions (molar ratio 3:1) are used to enhance the solubilities of the vanadium (>2.0 mol dm-3) and cerium species (>0.8 mol dm-3), thus achieving an energy density (c.a. 28 Wh dm-3) comparable to that of conventional all-vanadium redox flow batteries (20-30 Wh dm-3). Electrochemical studies, including cyclic voltammetry and galvanostatic cycling, show that both vanadium and cerium active species are suitable for energy storage applications in these electrolytes. To take advantage of the high open-circuit voltage (1.78 V), improved mass transport and reduced internal resistance are facilitated by the use of zero-gap flow field architecture, which yields a power density output of the battery of up to 370 mW cm-2 at a state-of-charge of 50%. In a charge-discharge cycle at 200 mA cm-2, the vanadium-cerium redox flow battery with the zero-gap architecture is observed to discharge at a cell voltage of c.a. 1.35 V with a coulombic efficiency of up to 78%.

Reduction and Smelting of Vanadium Titanomagnetite Metallized Pellets

NASA Astrophysics Data System (ADS)

Wang, Shuai; Chen, Mao; Guo, Yufeng; Jiang, Tao; Zhao, Baojun

2018-04-01

Reduction and smelting of the vanadium titanomagnetite metallized pellets have been experimentally investigated in this study. By using the high-temperature smelting, rapid quenching, and electron probe x-ray microanalysis (EPMA) technique, the effects of basicity, reaction time, and graphite reductant amount were investigated. The vanadium contents in iron alloys increase with increasing basicity, reaction time, and graphite amount, whereas the FeO and V2O3 concentrations in the liquid phase decrease with the increase of graphite amount and reaction time. Increasing the reaction time and reductant content promotes the reduction of titanium oxide, whereas the reduction of titanium oxides can be suppressed with increasing the slag basicity. Titanium carbide (TiC) was not observed in all the quenched samples under the present conditions. The experimental results and the FactSage calculations are also compared in the present study.

Low Permeable Hydrocarbon Polymer Electrolyte Membrane for Vanadium Redox Flow Battery.

PubMed

Jung, Ho-Young; Moon, Geon-O; Jung, Seunghun; Kim, Hee Tak; Kim, Sang-Chai; Roh, Sung-Hee

2017-04-01

Polymer electrolyte membrane (PEM) confirms the life span of vanadium redox flow battery (VRFB). Products from Dupont, Nafion membrane, is mainly used for PEM in VRFB. However, permeation of vanadium ion occurs because of Nafion’s high permeability. Therefore, the efficiency of VRFB decreases and the prices becomes higher, which hinders VRFB’s commercialization. In order to solve this problem, poly(phenylene oxide) (PPO) is sulfonated for the preparation of low-priced hydrocarbon polymer electrolyte membrane. sPPO membrane is characterized by fundamental properties and VRFB cell test.

ANIONIC EXCHANGE PROCESS FOR THE RECOVERY OF URANIUM AND VANADIUM FROM CARBONATE SOLUTIONS

DOEpatents

Bailes, R.H.; Ellis, D.A.; Long, R.S.

1958-12-16

Uranium and vanadium can be economically purified and recovered from non- salt roast carbonate leach liquors by adsorption on a strongly basic anionic exchange resin and subsequent selective elution by one of three alternative methods. Method 1 comprises selectively eluting uranium from the resin with an ammonium sulfate solution followed by eluting vanadium from the resin with either 5 M NaCl, saturated (NH/sub 4/)/sub 2/CO/sub 3/, saturated NaHCO/sub 3/, 1 M NaOH, or saturated S0/sub 2/ solutions. Method II comprises selectively eluting vanadium from the resin with either concentrated NaCl or S0/sub 2/ solutions subsequent to pretreatment of the column with either S0/sub 2/ gas, 1 N HCl, or 0.1 N H/sub 2/8O/sub 4/ followed by eluting uranium from the resin with solutions containing 0.9 M NH/sub 4/Cl or NaCl and 0.1 Cl. Method III comprises flowing the carbonate leac solutlon through a first column of a strongly basic anlonlc exchange resin untll vanadium breakthrough occurs, so that the effluent solution is enriched ln uranium content and the vanadium is chiefly retalned by the resln, absorbing the uranlum from the enriched effluent solution on a second column of a strongly basic anionic exchange resin, pretreating the first column with either 0.1 N HCl, 0.1 H/sub 2/SO/sub 4/, C0/sub 2/ gas, or ammonium sulfate, selectively eluting the vanadlum from the column with saturated S0/sub 2/ solution, pretreatlng the second column with either 0.1 N HCl or S0/sub 2/ gas, selectively eluting residual vanadium from the column with saturated S0/sub 2/ solution, and then eluting the uranium from the column with either 0.1 N HCl and 1 N NaCl orO.l N HCl and 1 N NH/sub 4/Cl.

Influence of V2O5 Content on the Gas-Based Direct Reduction of Hongge Vanadium Titanomagnetite Pellets with Simulated Shaft Furnace Gases

NASA Astrophysics Data System (ADS)

Li, Wei; Fu, Guiqin; Chu, Mansheng; Zhu, Miaoyong

2018-01-01

The influence of V2O5 content on the gas-based direct reduction of Hongge vanadium titanomagnetite pellets (HVTMP) was investigated with simulated shaft furnace gases, and the content levels were selected as 0 wt.%, 2 wt.%, 4 wt.%, and 6 wt.%, respectively. The results indicated that, with the increase of V2O5 content, the reduction was accelerated at an early stage due to the increase of the original porosity of the HVTMP. However, as the reduction proceeded, a slowing down in the reduction rate was observed, which was attributed to the formation of hardly reducible Fe2VO4. Major phases of reduced HVTMP were Fe2VO4, FeTiO3, and metallic iron. The morphology showed that the size of metallic iron particles of reduced HVTMP decreased with the increase of V2O5 content, V-bearing oxides embedded into the Ti-rich phases, and further reduction was restricted. This study not only established a relationship between the V2O5 content of HVTMP and its reduction behavior but could also contribute greatly to the effective utilization of Hongge vanadium titanomagnetite in shaft furnace.

[Determination of vanadium concentration in foods produced on the Eastern Coast of Lake Maracaibo].

PubMed

Tudares, C M; Villalobos, H D

1998-04-01

In the northeastern coast of Lake Maracaibo it has been reported some years ago a high incidence of congenital malformations of the Central Nervous Systems (Neural Tube Defects Type). This epidemiological problem is present in other countries too (Ireland and New Zealand) and has been associated with oil activities. In fact, some experimental works inform about the vanadium compounds cellular toxic effects mainly in the Central Nervous System of mammals. The main goal of this work is to measure the vanadium content in foods produced in the northeastern coast of Lake Maracaibo. Lagunillas, Valmore Rodriguez, and Baralt were the districts selected for the work. The digestion of the samples achieved by the methodology reported by Myron et al., with Graphite Furnace Atomic Absorption. The amounts of vanadium in the different foods analized were higher than the controls in the bibliographic reports. At this moment, there is not definitive proofs that vanadium compounds are the etiological agents of the Neural Tube Defects, but, these compounds are presents in foods produced in the northeastern coast of Lake Maracaibo.

Porous poly(benzimidazole) membrane for all vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Luo, Tao; David, Oana; Gendel, Youri; Wessling, Matthias

2016-04-01

Porous poly(benzimidazole) (PBI) membranes of low vanadium ions permeability are described for an all vanadium redox flow battery (VRFB). The PBI membrane was prepared by a water vapour induced phase inversion process of a PBI polymer solution. The membrane has a symmetrical cross-sectional morphology. A low water permeability of 16.5 L (m2 h bar)-1 indicates the high hydraulic resistance stemming from a closed cell morphology with nanoporous characteristics. The PBI membrane doped with 2.5 M H2SO4 shows a proton conductivity of 16.6 mS cm-1 and VO2+ permeability as low as 4.5 × 10-8 cm2 min-1. The stability test of dense PBI membrane in VO2+ solution indicates good chemical stability. An all vanadium redox flow battery (VRFB) operated with the porous PBI membrane shows 98% coulombic efficiency and more than 10% higher energy efficiency compared to VRFB operated with Nafion 112 at applied current densities of 20-40 mA cm-2. High in situ stability of the porous PBI membrane was confirmed by about 50 cycles of continuous charge and discharge operation of the battery.

Multiplier, moderator, and reflector materials for lithium-vanadium fusion blankets.

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

Gohar, Y.; Smith, D. L.

1999-10-07

The self-cooled lithium-vanadium fusion blanket concept has several attractive operational and environmental features. In this concept, liquid lithium works as the tritium breeder and coolant to alleviate issues of coolant breeder compatibility and reactivity. Vanadium alloy (V-4Cr-4Ti) is used as the structural material because of its superior performance relative to other alloys for this application. However, this concept has poor attenuation characteristics and energy multiplication for the DT neutrons. An advanced self-cooled lithium-vanadium fusion blanket concept has been developed to eliminate these drawbacks while maintaining all the attractive features of the conventional concept. An electrical insulator coating for the coolantmore » channels, spectral shifter (multiplier, and moderator) and reflector were utilized in the blanket design to enhance the blanket performance. In addition, the blanket was designed to have the capability to operate at high loading conditions of 2 MW/m{sup 2} surface heat flux and 10 MW/m{sup 2} neutron wall loading. This paper assesses the spectral shifter and the reflector materials and it defines the technological requirements of this advanced blanket concept.« less

Vanadium Exposure Induces Olfactory Dysfunction in an Animal Model of Metal Neurotoxicity

PubMed Central

Ngwa, Hilary Afeseh; Kanthasamy, Arthi; Jin, Huajun; Anantharam, Vellareddy; Kanthasamy, Anumantha G.

2014-01-01

Epidemiological evidence indicates chronic environmental exposure to transition metals may play a role in chronic neurodegenerative conditions such as Parkinson’s disease (PD). Chronic inhalation exposure to welding fumes containing metal mixtures may be associated with development of PD. A significant amount of vanadium is present in welding fumes, as vanadium pentoxide (V2O5), and incorporation of vanadium in the production of high strength steel has become more common. Despite the increased vanadium use in recent years, the neurotoxicological effects of this metal are not well characterized. Recently, we demonstrated that V2O5 induces dopaminergic neurotoxicity via protein kinase C delta (PKCδ)-dependent oxidative signaling mechanisms in dopaminergic neuronal cells. Since anosmia (inability to perceive odors) and non-motor deficits are considered to be early symptoms of neurological diseases, in the present study, we examined the effect of V2O5 on the olfactory bulb in animal models. To mimic the inhalation exposure, we intranasally administered C57 black mice a low-dose of 182 µg of V2O5 three times a week for one month, and behavioral, neurochemical and biochemical studies were performed. Our results revealed a significant decrease in olfactory bulb weights, tyrosine hydroxylase (TH) levels, levels of dopamine (DA) and its metabolite, 3, 4-dihydroxyphenylacetic acid (DOPAC) and increases in astroglia of the glomerular layer of the olfactory bulb in the treatment groups relative to vehicle controls. Neurochemical changes were accompanied by impaired olfaction and locomotion. These findings suggest that nasal exposure to V2O5 adversely affects olfactory bulbs, resulting in neurobehavioral and neurochemical impairments. These results expand our understanding of vanadium neurotoxicity in environmentally-linked neurological conditions. PMID:24362016

Evaluating transition state structures of vanadium-phosphatase protein complexes using shape analysis.

PubMed

Sánchez-Lombardo, Irma; Alvarez, Santiago; McLauchlan, Craig C; Crans, Debbie C

2015-06-01

Shape analysis of coordination complexes is well-suited to evaluate the subtle distortions in the trigonal bipyramidal (TBPY-5) geometry of vanadium coordinated in the active site of phosphatases and characterized by X-ray crystallography. Recent studies using the tau (τ) analysis support the assertion that vanadium is best described as a trigonal bipyramid, because this geometry is the ideal transition state geometry of the phosphate ester substrate hydrolysis (C.C. McLauchlan, B.J. Peters, G.R. Willsky, D.C. Crans, Coord. Chem. Rev. http://dx.doi.org/10.1016/j.ccr.2014.12.012 ; D.C. Crans, M.L. Tarlton, C.C. McLauchlan, Eur. J. Inorg. Chem. 2014, 4450-4468). Here we use continuous shape measures (CShM) analysis to investigate the structural space of the five-coordinate vanadium-phosphatase complexes associated with mechanistic transformations between the tetrahedral geometry and the five-coordinate high energy TBPY-5 geometry was discussed focusing on the protein tyrosine phosphatase 1B (PTP1B) enzyme. No evidence for square pyramidal geometries was observed in any vanadium-protein complexes. The shape analysis positioned the metal ion and the ligands in the active site reflecting the mechanism of the cleavage of the organic phosphate in a phosphatase. We identified the umbrella distortions to be directly on the reaction path between tetrahedral phosphate and the TBPY-5-types of high-energy species. The umbrella distortions of the trigonal bipyramid are therefore identified as being the most relevant types of transition state structures for the phosphoryl group transfer reactions for phosphatases and this may be related to the possibility that vanadium is an inhibitor for enzymes that support both exploded and five-coordinate transition states. Copyright © 2015 Elsevier Inc. All rights reserved.

In-Plane Impedance Spectroscopy measurements in Vanadium Dioxide thin films

NASA Astrophysics Data System (ADS)

Ramirez, Juan; Patino, Edgar; Schmidt, Rainer; Sharoni, Amos; Gomez, Maria; Schuller, Ivan

2012-02-01

In plane Impedance Spectroscopy measurements have been done in Vanadium Dioxide thin films in the range of 100 Hz to 1 MHz. Our measurements allows distinguishing between the resistive and capacitive response of the Vanadium Dioxide films across the metal-insulator transition. A non ideal RC behavior was found in our thin films from room temperature up to 334 K. Around the MIT, an increase of the total capacitance is observed. A capacitor-network model is able to reproduce the capacitance changes across the MIT. Above the MIT, the system behaves like a metal as expected, and a modified equivalent circuit is necessary to describe the impedance data adequately.

Critical safety features of the vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Whitehead, A. H.; Rabbow, T. J.; Trampert, M.; Pokorny, P.

2017-05-01

In this work the behaviour of the vanadium redox flow battery is examined under a variety of short-circuit conditions (e.g. with and without the pumps stopping as a result of the short). In contrast to other battery types, only a small proportion of the electroactive material, in a flow battery, is held between the electrodes at any given time. Therefore, together with the relatively low energy density of the vanadium electrolyte, the immediate release of energy, which occurs as a result of electrical shorting, is somewhat limited. The high heat capacity of the aqueous electrolyte is also beneficial in limiting the temperature rise. It will be seen that the flow battery is therefore considerably safer than other battery types, in this respect.

Exploring the Chemistry and Biology of Vanadium-dependent Haloperoxidases*

PubMed Central

Winter, Jaclyn M.; Moore, Bradley S.

2009-01-01

Nature has developed an exquisite array of methods to introduce halogen atoms into organic compounds. Most of these enzymes are oxidative and require either hydrogen peroxide or molecular oxygen as a cosubstrate to generate a reactive halogen atom for catalysis. Vanadium-dependent haloperoxidases contain a vanadate prosthetic group and utilize hydrogen peroxide to oxidize a halide ion into a reactive electrophilic intermediate. These metalloenzymes have a large distribution in nature, where they are present in macroalgae, fungi, and bacteria, but have been exclusively characterized in eukaryotes. In this minireview, we highlight the chemistry and biology of vanadium-dependent haloperoxidases from fungi and marine algae and the emergence of new bacterial members that extend the biological function of these poorly understood halogenating enzymes. PMID:19363038

Release kinetics of vanadium from vanadium titano-magnetite: The effects of pH, dissolved oxygen, temperature and foreign ions.

PubMed

Hu, Xingyun; Yue, Yuyan; Peng, Xianjia

2018-02-01

As part of a broader study of the environmental geochemistry behavior of vanadium (V), the release kinetics of V from the dissolution of natural vanadium titano-magnetite under environmentally relevant conditions was investigated. In both the acidic and basic domains, the V release rate was found to be proportional to fractional powers of hydrogen ion and dissolved oxygen activities. The dependence of the rate on dissolved oxygen can also be described in terms of the Langmuir adsorption model. The empirical rate equation is given by: r [Formula: see text] where, α=0.099-0.265, k'=3.2×10 -6 -1.7×10 -5 , K=2.7×10 4 -3.9×10 4 mol/L in acid solution (pH4.1), and α=-0.494-(-0.527), k'=2.0×10 4 -2.5×10 -11 , and K=4.1×10 3 -6.5×10 3 mol/L in basic solution (pH8.8) at 20°C. Based on the effect of temperature on the release rate of V, the activation energies of minerals at pH8.8 were determined to be 148-235kJ/mol, suggesting that the dissolution of vanadium titano-magnetite is a surface-controlled process. The presence of Na + , Ca 2+ , Mg 2+ , K + , NO 3 - , Cl - , SO 4 2- and CO 3 2- was found to accelerate the V release rates. This study improves the understanding of both the V pollution risk in some mine areas and the fate of V in the environment. Copyright © 2017. Published by Elsevier B.V.

Investigation of Silica-Supported Vanadium Oxide Catalysts by High-Field 51 V Magic-Angle Spinning NMR

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

Jaegers, Nicholas R.; Wan, Chuan; Hu, Mary Y.

Supported V2O5/SiO2 catalysts were studied using solid state 51V MAS NMR at a sample spinning rate of 36 kHz and at a magnetic field of 19.975 T for a better understanding of the coordination of the vanadium oxide as a function of environmental conditions . Structural transformations of the supported vanadium oxide species between the catalyst in the dehydrated state and hydrated state under an ambient environment were revisited to examine the degree of oligomerization and the effect of water. The experimental results indicate the existence of a single dehydrated surface vanadium oxide species that resonates at -675 ppm andmore » two vanadium oxide species under ambient conditions that resonate at -566 and -610 ppm, respectively. No detectable structural difference was found as a function of vanadium oxide loading on SiO2 (3% V2O5/SiO2 and 8% V2O5/SiO2). Quantum chemistry simulations of the 51V NMR chemical shifts on predicted surface structures were used as an aide in understanding potential surface vanadium oxide species on the silica support. The results suggest the formation of isolated surface VO4 units for the dehydrated catalysts with the possibility of dimer and cyclic trimer presence. The absence of bridging V-O-V vibrations (~200-300 cm-1) in the Raman spectra [Gao et al. J. Phys. Chem. B 1998, 102, 10842-10852], however, indicates that the isolated surface VO4 sites are the dominant dehydrated surface vanadia species on silica. Upon exposure to water, hydrolysis of the bridging V-O-Si bonds is most likely responsible for the decreased electron shielding experienced by vanadium. No indicators for the presence of hydrated decavanadate clusters or hydrated vanadia gels previously proposed in the literature were detected in this study.« less

Correlation between molten vanadium salts and the structural degradation of HK-type steel superheater tubes

NASA Astrophysics Data System (ADS)

de Carvalho Nunes, Frederico; de Almeida, Luiz Henrique; Ribeiro, André Freitas

2006-12-01

HK steels are among the most used heat-resistant cast stainless steels, being corrosion-resistant and showing good mechanical properties at high service temperatures. These steels are widely used in reformer furnaces and as superheater tubes. During service, combustion gases leaving the burners come in contact with these tubes, resulting in corrosive attack and a large weight loss occurs due to the presence of vanadium, which forms low melting point salts, removing the protective oxide layer. In this work the external surface of a tube with dramatic wall thickness reduction was analyzed using light microscopy, scanning electron microscopy, and transmission electron microscopy. The identification of the phases was achieved by energy dispersive spectroscopy (EDS) analyses. The results showed oxides arising from the external surface. In this oxidized region vanadium compounds inside chromium carbide particles were also observed, due to inward vanadium diffusion during corrosion attack. A chemical reaction was proposed to explain the presence of vanadium in the metal microstructure.

Balancing Osmotic Pressure of Electrolytes for Nanoporous Membrane Vanadium Redox Flow Battery with a Draw Solute.

PubMed

Yan, Ligen; Li, Dan; Li, Shuaiqiang; Xu, Zhi; Dong, Junhang; Jing, Wenheng; Xing, Weihong

2016-12-28

Vanadium redox flow batteries with nanoporous membranes (VRFBNM) have been demonstrated to be good energy storage devices. Yet the capacity decay due to permeation of vanadium and water makes their commercialization very difficult. Inspired by the forward osmosis (FO) mechanism, the VRFBNM battery capacity decrease was alleviated by adding a soluble draw solute (e.g., 2-methylimidazole) into the catholyte, which can counterbalance the osmotic pressure between the positive and negative half-cell. No change of the electrolyte volume has been observed after VRFBNM being operated for 55 h, revealing that the permeation of water and vanadium ions was effectively limited. Consequently, the Coulombic efficiency (CE) of nanoporous TiO 2 vanadium redox flow battery (VRFB) was enhanced from 93.5% to 95.3%, meanwhile, its capacity decay was significantly suppressed from 60.7% to 27.5% upon the addition of soluble draw solute. Moreover, the energy capacity of the VRFBNM was noticeably improved from 297.0 to 406.4 mAh remarkably. These results indicate balancing the osmotic pressure via the addition of draw solute can restrict pressure-dependent vanadium permeation and it can be established as a promising method for up-scaling VRFBNM application.

Visible light driven photocatalyst of vanadium (V3+) doped TiO2 synthesized using sonochemical method

NASA Astrophysics Data System (ADS)

Aini, N.; Ningsih, R.; Maulina, D.; Lami’, F. F.; Chasanah, S. N.

2018-03-01

TiO2 has been widely investigated due to its superior photocatalytic activity under ultraviolet irradiation among the photocatalyst materials. In this research, vanadium (V3+) was doped into TiO2 to enhance its light response under visible irradiation for wider application. Vanadium was introduced into TiO2 lattice at various concentration respectively 0.3, 0.5, 0.7 and 0.9% using simple and fast sonochemical method. X-Ray Diffraction data show that vanadium doped TiO2 crystallized in anatase phase with I41amd space group. X-Ray Diffraction pattern shifted to lower value of 2θ due to vanadium dopant. It indicated that V3+ was incorporated into anatase lattice. UV-Vis Diffuse Reflectance Spectra was revealed that the doped TiO2 has lowered reflectance and enhanced absorption coefficient in visible region than undoped TiO2 and commercial anatase TiO2. Band gap energy for undoped and doped TiO2 were respectively 3.22, 3.05, 2.93, 3.03 and 2.40 eV. Therefore vanadium doped TiO2 had potential to be applied under visible light.

Nickel and vanadium in air particulates at Dhahran (Saudi Arabia) during and after the Kuwait oil fires

NASA Astrophysics Data System (ADS)

Sadiq, M.; Mian, A. A.

Air particulates, both the total suspended (TSP) and inhalable (PM 10, smaller than 10 microns in size), were collected during and after the Kuwait oil fires (from March 1991 to July 1992) using Hi-Vol samplers. These samples were wet-digested at 120°C in an aqua regia and perchloric acids mixture for 3 h. Air particulate samples collected in 1982 at the same location were prepared similarly. Concentrations of nickel and vanadium were determined in the aliquot samples using an inductively coupled argon plasma analyser (ICAP). The monthly mean concentrations of nickel and vanadium, on volume basis, increased rapidly from March to June and decreased sharply during July-August in 1991. The minimum mean concentrations of these elements were found in the particulate samples collected in December 1991 which gradually increased through May 1992. Like 1991, nickel and vanadium concentrations in the air particulates spiked in June and decreased again in July 1992. This distribution pattern of nickel and vanadium concentrations was similar to that of the predominant wind from the north (Kuwait). In general, concentrations of these elements were higher in the air particulates collected during April-July 1991 as compared with those collected in 1992 during the same period. The TSPs contained higher concentrations of nickel and vanadium than those found in the PM 10 samples. However, this trend was reversed when concentrations of nickel and vanadium, on were expressed on particulate weight basis. The monthly mean concentrations of nickel and vanadium, on weight basis, decreased gradually through 1991 and increased slightly from March to July 1992. Concentrations of these elements were significantly higher in the air particulate samples collected in 1991 than those samples collected during 1982 at the same location. The data of this study suggest a contribution of the Kuwait oil fires in elevating nickel and vanadium concentrations in the air particulates at Dhahran during

1. VIEW TO EAST, FRONT AND SIDE. Vanadium Corporation ...

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

1. VIEW TO EAST, FRONT AND SIDE. - Vanadium Corporation of America (VCA) Naturita Mill, Mechanic Shed, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

2. VIEW TO WEST, REAR AND SIDE. Vanadium Corporation ...

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

2. VIEW TO WEST, REAR AND SIDE. - Vanadium Corporation of America (VCA) Naturita Mill, Mechanic Shed, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

77 FR 46712 - Ferrovanadium and Nitrided Vanadium From the Russian Federation: Negative Final Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-06

... Determination We determine that the importation of vanadium pentoxide from the Russian Federation (Russia) by...) from Russia, within the meaning of section 781(a) of the Tariff Act of 1930, as amended (the Act). \\1... its negative preliminary determination that Evraz's imports of vanadium pentoxide from Russia that are...

Multiplier, moderator, and reflector materials for advanced lithium?vanadium fusion blankets

NASA Astrophysics Data System (ADS)

Gohar, Y.; Smith, D. L.

2000-12-01

The self-cooled lithium-vanadium fusion blanket concept has several attractive operational and environmental features. In this concept, liquid lithium works as the tritium breeder and coolant to alleviate issues of coolant breeder compatibility and reactivity. Vanadium alloy (V-4Cr-4Ti) is used as the structural material because of its superior performance relative to other alloys for this application. However, this concept has poor attenuation characteristics and energy multiplication for the DT neutrons. An advanced self-cooled lithium-vanadium fusion blanket concept has been developed to eliminate these drawbacks while maintaining all the attractive features of the conventional concept. An electrical insulator coating for the coolant channels, spectral shifter (multiplier, and moderator) and reflector were utilized in the blanket design to enhance the blanket performance. In addition, the blanket was designed to have the capability to operate at average loading conditions of 2 MW/m 2 surface heat flux and 10 MW/m 2 neutron wall loading. This paper assesses the spectral shifter and the reflector materials and it defines the technological requirements of this advanced blanket concept.

1. VIEW TO EAST, FRONT AND SIDE. Vanadium Corporation ...

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

1. VIEW TO EAST, FRONT AND SIDE. - Vanadium Corporation of America (VCA) Naturita Mill, Grinding Rod Mill, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

Determination of total vanadium and vanadium(V) in groundwater from Mt. Etna and estimate of daily intake of vanadium(V) through drinking water.

PubMed

Arena, Giovanni; Copat, Chiara; Dimartino, Angela; Grasso, Alfina; Fallico, Roberto; Sciacca, Salvatore; Fiore, Maria; Ferrante, Margherita

2015-06-01

Vanadium(V) can be found in natural waters in the form of V(IV) and V(V) species, which have different biological properties and toxicity. The purpose of this study was to determine the concentrations of total V and V(V) in groundwater from the area of Mt. Etna and to assess the estimated daily intake (EDI) of V(V) of adults and children through drinking water. Water was sampled monthly at 21 sites in 2011. Total vanadium was determined by inductively coupled plasma-mass spectrometry (ICP-MS) and speciation by ion chromatography-ICP-MS (IC-ICP-MS). The concentration of V(V) species ranged from 62.8 to 98.9% of total V, with significantly higher concentrations in samples from the S/SW slope of Mt. Etna. The annual mean concentrations of total V exceeded the Italian legal limit of 140 μg/L at four sites on the S/SW slope. In the absence of thresholds for V(V) intake, only the Environmental Protection Agency (EPA) has calculated a reference dose. Children's EDI of V(V) at the sites with the higher V concentrations exceeded EPA thresholds (9 μg/kg/day). In particular, we found in Camporotondo, Mascalucia, Ragalna and San Pietro Clarenza sites children's EDIs of 11, 9.3, 11 and 9.9, respectively. The EDI of V(V) was significantly higher than the literature range (0.09-0.34 μg/kg/day).

Structural characterization and anticancer activity of extracellular polysaccharides from ascidian symbiotic bacterium Bacillus thuringiensis.

PubMed

Ramamoorthy, Sathishkumar; Gnanakan, Ananthan; S Lakshmana, Senthil; Meivelu, Moovendhan; Jeganathan, Arun

2018-06-15

In the present study, extracellular polysaccharides (EPS) producing bacterium Bacillus thuringiensis RSK CAS4 was isolated from ascidian Didemnum granulatum and its production was optimized by response surface methodology. Fructose and galactose were found as the major monosaccharides in the EPS from the strain RSK CAS4. Functional groups and structural characteristics of the EPS were characterized with FT-IR and 1 HNMR. The purified EPS showed potent antioxidant properties in investigation against DPPH, hydroxyl, superoxide free radicals. In vitro anticancer activity of purified EPS was evaluated on HEp-2 cells, A549 and Vero cell lines. Growth of cancer cells was inhibited by the EPS in a dose-dependent manner and maximum anticancer activity was found to be 76% against liver cancer at 1000 μg/ml. The antioxidant and anticancer potentials of theEPS from marine bacterium Bacillusthuringiensis RSK CAS4 suggests it as a potential natural source and its scopeas an alternative to synthetics for pharmaceutical application. Copyright © 2018 Elsevier Ltd. All rights reserved.

4. DETAIL OF GEARWELL AND GENERATOR, WEST VIEW. Vanadium ...

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

4. DETAIL OF GEARWELL AND GENERATOR, WEST VIEW. - Vanadium Corporation of America (VCA) Naturita Mill, Grinding Rod Mill, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

Mechanochemical processing of molybdenum and vanadium sulfides for metal recovery from spent catalysts wastes.

PubMed

Li, Zhao; Chen, Min; Zhang, Qiwu; Liu, Xinzhong; Saito, Fumio

2017-02-01

This work describes the mechanochemical transformations of molybdenum and vanadium sulfides into corresponding molybdate and vanadate, to serve as a new environment-friendly approach for processing hazardous spent hydrodesulphurization (HDS) catalysts solid waste to achieve an easy recovery of not only molybdenum and vanadium but also nickel and cobalt. Co-grinding the molybdenum and vanadium sulfides with oxidants and sodium carbonate stimulates solid-state reactions without any heating aid to form metal molybdates and vanadates. The reactions proceed with an increase in grinding time and were enhanced by using more sodium carbonate and stronger oxidant. The necessary conditions for the successful transformation can be explained on the basis of thermodynamic analyses, namely a negative change in Gibbs free energy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solution XAS Analysis for Exploring the Active Species in Homogeneous Vanadium Complex Catalysis

NASA Astrophysics Data System (ADS)

Nomura, Kotohiro; Mitsudome, Takato; Tsutsumi, Ken; Yamazoe, Seiji

2018-06-01

Selected examples in V K-edge X-ray Absorption Near Edge Structure (XANES) analysis of a series of vanadium complexes containing imido ligands (possessing metal-nitrogen double bond) in toluene solution have been introduced, and their pre-edge and the edge were affected by their structures and nature of ligands. Selected results in exploring the oxidation states of the active species in ethylene dimerization/polymerization using homogeneous vanadium catalysts [consisting of (imido)vanadium(V) complexes and Al cocatalysts] by X-ray absorption spectroscopy (XAS) analyses have been introduced. It has been demonstrated that the method should provide more clear information concerning the active species in situ, especially by combination with the other methods (NMR and ESR spectra, X-ray crystallographic analysis, and reaction chemistry), and should be powerful tool for study of catalysis mechanism as well as for the structural analysis in solution.

Regeneration of the gut requires retinoic acid in the budding ascidian Polyandrocarpa misakiensis.

PubMed

Kaneko, Nagamoto; Katsuyama, You; Kawamura, Kazuo; Fujiwara, Shigeki

2010-06-01

The protochordate ascidian Polyandrocarpa misakiensis has a striking ability to regenerate. When the posterior half of the adult body is amputated, the anterior half completely loses the esophagus, stomach and intestine. These organs are reconstituted in a week. Histological observation revealed that the regeneration involves transdifferentiation of the atrial epithelium near the cut surface. The morphological features of the gut primordium were similar to those observed in the developing bud of this species. Inhibitors of the synthesis of retinoic acid (RA) suppressed the formation of the gut. 13-cis RA rescued the regenerates from the inhibitor-induced hypoplasia. These results suggest that RA is required for the regeneration of the gut. A gene encoding the RA receptor (Pm-RAR) and its target gene, TRAMP, were expressed in and around the regenerating gut. Pm-RAR-specific and TRAMP-specific double-stranded RNA molecules inhibited the regeneration of the gut, indicating that the RA signal is mediated at least in part by Pm-RAR and TRAMP. These results suggested that RA triggers the transdifferentiation of the atrial epithelium into the gut in regenerating animals, as it does during asexual reproduction.

A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis

DOE PAGES

Gilchrist, Michael J.; Sobral, Daniel; Khoueiry, Pierre; ...

2015-05-27

Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We also report a computational strategy that overcomes these difficulties,more » and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5'- and 3'-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. Here, we developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Furthermore, using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes.« less

Raman effect in icosahedral boron-rich solids

PubMed Central

Werheit, Helmut; Filipov, Volodymyr; Kuhlmann, Udo; Schwarz, Ulrich; Armbrüster, Marc; Leithe-Jasper, Andreas; Tanaka, Takaho; Higashi, Iwami; Lundström, Torsten; Gurin, Vladimir N; Korsukova, Maria M

2010-01-01

We present Raman spectra of numerous icosahedral boron-rich solids having the structure of α-rhombohedral, β-rhombohedral, α-tetragonal, β-tetragonal, YB66, orthorhombic or amorphous boron. The spectra were newly measured and, in some cases, compared with reported data and discussed. We emphasize the importance of a high signal-to-noise ratio in the Raman spectra for detecting weak effects evoked by the modification of compounds, accommodation of interstitial atoms and other structural defects. Vibrations of the icosahedra, occurring in all the spectra, are interpreted using the description of modes in α-rhombohedral boron by Beckel et al. The Raman spectrum of boron carbide is largely clarified. Relative intra- and inter-icosahedral bonding forces are estimated for the different structural groups and for vanadium-doped β-rhombohedral boron. The validity of Badger's rule is demonstrated for the force constants of inter-icosahedral B–B bonds, whereas the agreement is less satisfactory for the intra-icosahedral B–B bonds. PMID:27877328

Understanding the Reduction Kinetics of Aqueous Vanadium(V) and Transformation Products Using Rotating Ring-Disk Electrodes.

PubMed

Chen, Gongde; Liu, Haizhou

2017-10-17

Vanadium(V) is an emerging contaminant in the most recent Environmental Protection Agency's candidate contaminant list (CCL4). The redox chemistry of vanadium controls its occurrence in the aquatic environment, but the impact of vanadium(V) speciation on the redox properties remains largely unknown. This study utilized the rotating ring-disk electrode technique to examine the reduction kinetics of four pH- and concentration-dependent vanadium(V) species in the presence and the absence of phosphate. Results showed that the reduction of VO 2 + , H x V 4 O 12+x (4+x)- (V 4 ), and HVO 4 2- proceeded via a one-electron transfer, while that of Na x H y V 10 O 28 (6-x-y)- (V 10 ) underwent a two-electron transfer. Koutecky-Levich and Tafel analyses showed that the intrinsic reduction rate constants followed the order of V 10 > VO 2 + > V 4 > HVO 4 2- . Ring-electrode collection efficiency indicated that the reduction product of V 10 was stable, while those of VO 2 + , HVO 4 2- , and V 4 had short half-lives that ranged from milliseconds to seconds. With molar ratios of phosphate to vanadium(V) varying from 0 to 1, phosphate accelerated the reduction kinetics of V 10 and V 4 and enhanced the stability of the reduction products of VO 2 + , V 4 , and HVO 4 2- . This study suggests that phosphate complexation could enhance the reductive removal of vanadium(V) and inhibit the reoxidation of its reduction product in water treatment.

Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat

USGS Publications Warehouse

Valentine, P.C.; Carman, M.R.; Blackwood, D.S.; Heffron, E.J.

2007-01-01

The colonial ascidian Didemnum sp. has colonized northwestern Atlantic coastal habitats from southern Long Island, New York, to Eastport, Maine. It is also present in offshore habitats of the Georges Bank fishing grounds. It threatens to alter fisheries habitats and shellfish aquacultures. Observations in a tide pool at Sandwich, MA from December 2003 to February 2006 show that Didemnum sp. tolerates water temperatures ranging from ≤ 1 to > 24 °C, with daily changes of up to 11 °C. It attaches to pebbles, cobbles, and boulders, and it overgrows other tunicates, seaweeds, sponges, and bivalves. From May to mid July, colonies appear as small patches on the bottoms of rocks. Colonies grow rapidly from July to September, with some growth into December, and they range in color from pink to pale yellow to pale orange. Colony health declines from October through April, presumably in response to changes in water temperatures, and this degenerative process is manifested by color changes, by the appearance of small dark brown spots that represent clumps of fecal pellets in the colony, by scavenging by periwinkles, and by a peeling-away of colonies from the sides of cobbles and boulders. At Sandwich, colonies died that were exposed to air at low tide. The species does not exhibit this seasonal cycle of growth and decline in subtidal habitats (40–65 m) on the Georges Bank fishing grounds where the daily climate is relatively stable and annual water temperatures range from 4 to 15 °C. Experiments in the tide pool with small colony fragments (5 to 9 cm2) show they re-attach and grow rapidly by asexual budding, increasing in size 6- to 11-fold in the first 15 days. Didemnum sp. at Sandwich has no known predators except for common periwinkles (Littorina littorea) that graze on degenerating colonies in the October to April time period and whenever colonies are stressed by desiccation. The tendencies of the ascidian (1) to attach to firm substrates, (2) to rapidly overgrow

High-Fat Diet Increased Renal and Hepatic Oxidative Stress Induced by Vanadium of Wistar Rat.

PubMed

Wang, J P; Cui, R Y; Zhang, K Y; Ding, X M; Luo, Y H; Bai, S P; Zeng, Q F; Xuan, Y; Su, Z W

2016-04-01

The study was conducted to assess the effect of vanadium (V) in high-fat diet on the liver and kidney of rats in a 5-week trial. Seventy-two female Wistar rats (BW = 95 ± 5 g) were randomly allotted into eight groups. Groups I, II, III, and IV obtained low-fat diet containing 0, 3, 15, and 30 mg/kg V, and V, VI, VII, and VIII groups received the respective vanadium doses with high-fat diet, respectively. There were lesions in the liver and kidney of V, VI, VII, and VIII groups, granular degeneration and vacuolar degeneration were observed in the renal tubular and glomerulus epithelial cells, and hepatocytes showed granular degeneration and vacuolar degeneration. Supplemented high-fat diet with vanadium was shown to decrease (P < 0.05) activities of superoxide dismutase, total antioxidant capacity, glutathione-S transferase, and NAD(P)H/quinone oxidoreductase 1 (NQO1) and increase malondialdehyde content in the liver and kidney. The relative expression of hepatic nuclear factor erythroid 2-related factor 2 (Nrf-2) and NQO1 mRNA was downregulated by V addition and high-fat diet, and the effect of V was more pronounced in high-fat diet (interaction, P < 0.05), with VIII group having the lowest mRNA expression of Nrf-2 and NQO1 in the liver and kidney. In conclusion, it suggested that dietary vanadium ranging from 15 to 30 mg/kg could lead to oxidative damage and vanadium accumulation in the liver and kidney, which caused renal and hepatic toxicity. The high-fat diet enhanced vanadium-induced hepatic and renal damage, and the mechanism was related to the modulation of the hepatic and renal mRNA expression of Nrf-2 and NQO1.

Selective speciation improves efficacy and lowers toxicity of platinum anticancer and vanadium antidiabetic drugs.

PubMed

Doucette, Kaitlin A; Hassell, Kelly N; Crans, Debbie C

2016-12-01

Improving efficacy and lowering resistance to metal-based drugs can be addressed by consideration of the coordination complex speciation and key reactions important to vanadium antidiabetic drugs or platinum anticancer drugs under biological conditions. The methods of analyses vary depending on the specific metal ion chemistry. The vanadium compounds interconvert readily, whereas the reactions of the platinum compounds are much slower and thus much easier to study. However, the vanadium species are readily differentiated due to vanadium complexes differing in color. For both vanadium and platinum systems, understanding the processes as the compounds, Lipoplatin and Satraplatin, enter cells is needed to better combat the disease; there are many cellular metabolites, which may affect processing and thus the efficacy of the drugs. Examples of two formulations of platinum compounds illustrate how changing the chemistry of the platinum will result in less toxic and better tolerated drugs. The consequence of the much lower toxicity of the drug, can be readily realized because cisplatin administration requires hospital stay whereas Lipoplatin can be done in an outpatient manner. Similarly, the properties of Satraplatin allow for development of an oral drug. These forms of platinum demonstrate that the direct consequence of more selective speciation is lower side effects and cheaper administration of the anticancer agent. Therefore we urge that as the community goes forward in development of new drugs, control of speciation chemistry will be considered as one of the key strategies in the future development of anticancer drugs. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of nitrogen on precipitation and transformation kinetics in vanadium steels

NASA Astrophysics Data System (ADS)

Balliger, N. K.; Honeycombe, R. W. K.

1980-03-01

The isothermal decomposition of austenite has been studied in a series of vanadium steels containing varying amounts of carbon and nitrogen, (in approximately stoichio-metric proportions), in the temperature range 700 to 850°C. In the basic alloy, Fe-0.27V-0.05C (composition in wt pct), below 810°C the austenite to polygonal ferrite trans-formation is accompanied by interphase precipitation of vanadium carbide, the finer dis-persions being associated with the lower transformation temperatures. However, below 760°C there is an additional precipitation reaction where dislocation precipitation of vanadium carbide predominates; this is shown to occur in association with Widmanstätten ferrite. Above 810° C, a proeutectoid ferrite reaction results, the ferrite being void of precipitates; evidence is provided to show that partitioning of vanadium from ferrite to austenite occurs during the transformation. In the two steels containing nitrogen, namely Fe-0.26V-0.022N-0.020C and Fe-0.29V-0.032 N the basic interphase precipitation re-action is unchanged, but the resultant precipitate dispersions are finer at a given trans-formation temperature. The temperature range over which interphase precipitation oc-curs is expanded by the presence of nitrogen, since the Widmanstätten start tempera-ture is depressed and the proeutectoid ferrite reaction is inhibited. Precipitation in austenite prior to transformation and twin formation during transformation are both en-couraged by the presence of nitrogen.

Thermally Stable Solution Processed Vanadium Oxide as a Hole Extraction Layer in Organic Solar Cells

PubMed Central

Alsulami, Abdullah; Griffin, Jonathan; Alqurashi, Rania; Yi, Hunan; Iraqi, Ahmed; Lidzey, David; Buckley, Alastair

2016-01-01

Low-temperature solution-processable vanadium oxide (V2Ox) thin films have been employed as hole extraction layers (HELs) in polymer bulk heterojunction solar cells. V2Ox films were fabricated in air by spin-coating vanadium(V) oxytriisopropoxide (s-V2Ox) at room temperature without the need for further thermal annealing. The deposited vanadium(V) oxytriisopropoxide film undergoes hydrolysis in air, converting to V2Ox with optical and electronic properties comparable to vacuum-deposited V2O5. When s-V2Ox thin films were annealed in air at temperatures of 100 °C and 200 °C, OPV devices showed similar results with good thermal stability and better light transparency. Annealing at 300 °C and 400 °C resulted in a power conversion efficiency (PCE) of 5% with a decrement approximately 15% lower than that of unannealed films; this is due to the relative decrease in the shunt resistance (Rsh) and an increase in the series resistance (Rs) related to changes in the oxidation state of vanadium. PMID:28773356

Investigation of local environments in Nafion-SiO(2) composite membranes used in vanadium redox flow batteries.

PubMed

Vijayakumar, M; Schwenzer, Birgit; Kim, Soowhan; Yang, Zhenguo; Thevuthasan, S; Liu, Jun; Graff, Gordon L; Hu, Jianzhi

2012-04-01

Proton conducting polymer composite membranes are of technological interest in many energy devices such as fuel cells and redox flow batteries. In particular, polymer composite membranes, such as SiO(2) incorporated Nafion membranes, are recently reported as highly promising for the use in redox flow batteries. However, there is conflicting reports regarding the performance of this type of Nafion-SiO(2) composite membrane in the redox flow cell. This paper presents results of the analysis of the Nafion-SiO(2) composite membrane used in a vanadium redox flow battery by nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier Transform Infra Red (FTIR) spectroscopy, and ultraviolet-visible spectroscopy. The XPS study reveals the chemical identity and environment of vanadium cations accumulated at the surface. On the other hand, the (19)F and (29)Si NMR measurement explores the nature of the interaction between the silica particles, Nafion side chains and diffused vanadium cations. The (29)Si NMR shows that the silica particles interact via hydrogen bonds with the sulfonic groups of Nafion and the diffused vanadium cations. Based on these spectroscopic studies, the chemical environment of the silica particles inside the Nafion membrane and their interaction with diffusing vanadium cations during flow cell operations are discussed. This study discusses the origin of performance degradation of the Nafion-SiO(2) composite membrane materials in vanadium redox flow batteries. Copyright © 2011 Elsevier Inc. All rights reserved.

Investigation of Local Environments in Nafion-SiO2 Composite Membranes used in Vanadium Redox Flow Batteries

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

Vijayakumar, M.; Schwenzer, Birgit; Kim, Soowhan

2012-04-01

The proton conducting polymer composite membranes are of technological interest in many energy devices such as fuel cells and redox flow batteries. In particular, the polymer composite membranes such as SiO2 incorporated Nafion membranes are recently reported as highly promising for the redox flow batteries. However, there is conflicting reports regarding the performance of this Nafion-SiO2 composite membrane in the redox flow cell. This paper presents results of the analysis of the Nafion-SiO2 composite membrane used in a vanadium redox flow battery by nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier Transformed Infra Red (FTIR) spectroscopy, and ultravioletmore » visible spectroscopy. The XPS study reveals the chemical identity and environment of vanadium cations accumulated at the surface. On the other hand, the 19F and 29Si NMR measurement explores the nature of the interaction between the silica particles, Nafion side chains and diffused vanadium cations. The 29Si NMR shows that the silica particles interaction via hydrogen bonds to the sulfonic groups of Nafion and diffused vanadium cations. Based on these spectroscopic studies, the chemical environment of the silica particles inside the Nafion membrane and their interaction with diffusing vanadium cations during flow cell operations are discussed. This study discusses the origin of performance degradation of the Nafion-SiO2 composite membrane materials in vanadium redox flow batteries.« less

Determination of mercury and vanadium concentration in Johnius belangerii (C) fish in Musa estuary in Persian Gulf.

PubMed

Fard, Neamat Jaafarzadeh Haghighi; Ravanbakhsh, Maryam; Ramezani, Zahra; Ahmadi, Mehdi; Angali, Kambiz Ahmadi; Javid, Ahmad Zare

2015-08-15

The main aim of this study was to determine the concentrations of mercury and vanadium in Johnius belangerii (C) fish in the Musa estuary. A total of 67 fishes were caught from the Musa estuary during five intervals of 15days in the summer of 2013. After biometric measurements were conducted, the concentrations of mercury and vanadium were measured in the muscle tissue of fish using a direct method analyzer (DMA) and a graphite furnace atomic absorption spectrophotometer, respectively. The mean concentration of mercury and vanadium in the muscle tissue of fish was 3.154±1.981 and 2.921±0.873mg/kg w.w, respectively. The generalized linear model (GLM) analysis showed a significantly positive relationship among mercury concentration, length, and weight (P=0.000). In addition, there was a significantly negative relationship between vanadium concentration and fish length (P=0.000). A reverse association was found between concentrations of mercury and vanadium. Mercury concentration exceeded the allowable standards of the Environmental Protection Agency (EPA), the World Health Organization (WHO), and the Food and Drug Administration (FDA) in J. belangerii (C). Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of vanadium ions in barium borate glass

NASA Astrophysics Data System (ADS)

Abdelghany, A. M.; Hammad, Ahmed H.

2015-02-01

Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.

Impact of vanadium ions in barium borate glass.

PubMed

Abdelghany, A M; Hammad, Ahmed H

2015-02-25

Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data. Copyright © 2014 Elsevier B.V. All rights reserved.

Structural investigation of phosphate - bismuth glasses with vanadium

NASA Astrophysics Data System (ADS)

Stǎnescu, R.; Vedeanu, N.; Cozar, I. B.; Mǎgdaş, A.

2013-11-01

The xV2O5(1-dx)[0.5P2O5ṡ0.5Bi2O3] glass system with 0 ≤ x ≤ 50 mol% is investigated by IR and Raman spectroscopy. Both P2O5 and Bi2O3 oxides are known as network formers, but Bi2O3 is an unconventional one. At low content of vanadium oxide (x ≤ 5 mol%), both IR and Raman spectra are dominated by vibration bands characteristics to structural groups of phosphate and bismuthate lattices. Due to the network modifier role, vanadium oxide acts mainly on the Bi2O3 network allowing the phosphate groups to impose their characteristics absorption bands in spectra. These bands are strongly reduced for x ≥ 20 mol% due to the phosphate network depolymerization and the appearance of new vibrations characteristic to P-O-V, Bi-O-V and V-O-V groups showing the network former role of V2O5.

Orientation of Vanadium Dioxide Grains on Various Substrates

NASA Astrophysics Data System (ADS)

Rivera, Felipe; Davis, Robert; Vanfleet, Richard

2010-10-01

Crystalline vanadium dioxide VO2 experiences a fast and reversible semiconductor-to-metal structural phase transition near 68^oC. The changes exhibited during this phase transition comprise a well known change in resistivity of several orders of magnitude, as well as a significant drop in optical transmittance in the infrared. Due to the changes in these optical and electronic properties, vanadium dioxide shows promise as a material to be used in many applications ranging from thermochromic window coatings to optoelectronic devices. However, since there is a structural component to the phase transition of VO2, it is of interest to study the orientation of the crystalline grains deposited. Substrates such as glass, SiO2, Sapphire, and TiO2 have been used for the deposition of this material. We used orientation imaging microscopy to study and characterize the orientation of the grains deposited on several of these substrates. Here we present results on this study.

Vanadium Induces Dopaminergic Neurotoxicity Via Protein Kinase C-Delta Dependent Oxidative Signaling Mechanisms: Relevance to Etiopathogenesis of Parkinson's Disease

PubMed Central

Afeseh Ngwa, Hilary; Kanthasamy, Arthi; Anantharam, Vellareddy; Song, Chunjuan; Witte, Travis; Houk, R. S.; Kanthasamy, Anumantha G.

2009-01-01

Environmental exposure to neurotoxic metals through various sources including exposure to welding fumes has been linked to an increased incidence of Parkinson's disease (PD). Welding fumes contain many different metals including vanadium typically present as particulates containing vanadium pentoxide (V2O5). However, possible neurotoxic effects of this metal oxide on dopaminergic neuronal cells are not well studied. In the present study, we characterized vanadium-induced oxidative stress-dependent cellular events in cell culture models of PD. V2O5 was neurotoxic to dopaminergic neuronal cells including primary nigral dopaminergic neurons and the EC50 was determined to be 37 μM in N27 dopaminergic neuronal cell model. The neurotoxic effect was accompanied by a time-dependent uptake of vanadium and upregulation of metal transporter proteins Tf and DMT1 in N27 cells. Additionally, vanadium resulted in a threefold increase in reactive oxygen species generation, followed by release of mitochondrial cytochrome c into cytoplasm and subsequent activation of caspase-9 (>fourfold) and caspase-3 (>ninefold). Interestingly, vanadium exposure induced proteolytic cleavage of native protein kinase Cdelta (PKCδ, 72-74 kDa) to yield a 41 kDa catalytically active fragment resulting in a persistent increase in PKCδ kinase activity. Co-treatment with pan-caspase inhibitor ZVAD-FMK significantly blocked vanadium-induced PKCδ proteolytic activation, indicating that caspases mediate PKCδ cleavage. Also, co-treatment with Z-VAD-FMK almost completely inhibited V2O5-induced DNA fragmentation. Furthermore, PKCδ knockdown using siRNA protected N27 cells from V2O5-induced apoptotic cell death. Collectively, these results demonstrate vanadium can exert neurotoxic effects in dopaminergic neuronal cells via caspase-3-dependent PKCδ cleavage, suggesting that metal exposure may promote nigral dopaminergic degeneration. PMID:19646462

[Determination of Fe, Ti and V in vanadium and titanium magnetite by ICP-OES and microwave-assisted digestion].

PubMed

Zhu, Xia-ping; Yin, Ji-xian; Chen, Wei-dong; Hu, Zi-Wen; Liang, Qing-xun; Chen, Tie-yao

2010-08-01

The method of determination of iron, titanium and vanadium in indissolvable vanadium and titanium magnetite has been established by inductively coupled plasma atomic emission spectroscopy through adding the complexant A and using microwave-assisted digestion. The optimal conditions are confirmed by orthogonal experiment: 0.1 g vanadium and titanium magnetite, 0.04 g complexant A, 12 mL concentrated HC1, 10 min digestion time, and 385 W microwave power. The newly-established method has been applied to digest vanadium and titanium magnetite of Panzhihua Iron and Steel Institute (GBW07226). The iron, titanium and vanadium were detected by ICP-OES, and both comparative error (Er%) and comparative standard deviation (RSD%) met the demand of analytical chemistry, and the complexant A can significantly accelerate the dissolution of vanadium and titanium magnetite through the complexation with the dissolved metal ions, and making the surface of sample and hydrochloric acid medium to update constantly. The determination of the main and trace elements of digestion solution at the same time was achieved by ICP-OES. The method has the advantages of less use of reagents, economy, rapidness, and being friendly to environment, and it meets the requirement for rapid and volume determination. So the method has the value of practical application for the entry-exit inspection and quarantine department of the state and other relevant inspection units.

Corrosion resistance investigation of vanadium alloys in liquid lithium

NASA Astrophysics Data System (ADS)

Borovitskaya, I. V.; Lyublinskiy, I. E.; Bondarenko, G. G.; Paramonova, V. V.; Korshunov, S. N.; Mansurova, A. N.; Lyakhovitskiy, M. M.; Zharkov, M. Yu.

2016-12-01

A major concern in using vanadium alloys for first wall/blanket systems in fusion reactors is their activity with regard to nonmetallic impurities in the coolants. This paper presents the results of studying the corrosion resistance in high-purity liquid lithium (with the nitrogen and carbon content of less than 10-3 wt %) of vanadium and vanadium alloys (V-1.86Ga, V-3.4Ga-0.62Si, V-4.81Ti-4.82Cr) both in the initial state and preliminarily irradiated with Ar+ ions with energy of 20 keV to a dose of 1022 m-2 at an irradiation temperature of 400°C. The degree of corrosion was estimated by measuring the changes in the weight and microhardness. Corrosion tests were carried out under static isothermal conditions at a temperature of 600°C for 400 h. The identity of corrosion mechanisms of materials both irradiated with Ar ions and not irradiated, which consisted in an insignificant penetration of nitrogen into the materials and a substantial escape of oxygen from the materials, causing the formation of a zone with a reduced microhardness near the surface, was established. The influence of the corrosive action of lithium on the surface morphology of the materials under study was found, resulting in the manifestation of grain boundaries and slip lines on the sample surface, the latter being most clearly observed in the case of preliminary irradiation with Ar ions.

Bifunctional Crosslinking Agents Enhance Anion Exchange Membrane Efficacy for Vanadium Redox Flow Batteries.

PubMed

Wang, Wenpin; Xu, Min; Wang, Shubo; Xie, Xiaofeng; Lv, Yafei; Ramani, Vijay K

2014-06-02

A series of cross-linked fluorinated poly (aryl ether oxadiazole) membranes (FPAEOM) derivatized with imidazolium groups were prepared. Poly (N-vinylimidazole) (PVI) was used as the bifunctional cross-linking agent to: a) lower vanadium permeability, b) enhance dimensional stability, and c) concomitantly provide added ion exchange capacity in the resultant anion exchange membranes. At a molar ratio of PVI to FPAEOM of 1.5, the resultant membrane (FPAEOM-1.5 PVI) had an ion exchange capacity of 2.2 meq g-1, a vanadium permeability of 6.8×10-7 cm2 min-1, a water uptake of 68 wt.%, and an ionic conductivity of 22.0 mS cm-1, all at 25°C. Single cells prepared with the FPAEOM-1.5 PVI membrane exhibited a higher coulombic efficiency (> 92%) and energy efficiency (> 86%) after 40 test cycles in vanadium redox flow battery. The imidazolium cation showed high chemical stability in highly acidic and oxidizing vanadium solution as opposed to poor stability in alkaline solutions. Based on our DFT studies, this was attributed to the lower HOMO energy (-7.265 eV) of the HSO4- ion (compared to the OH- ion; -5.496 eV) and the larger HOMO-LUMO energy gap (6.394 eV) of dimethylimidazolium bisulfate ([DMIM] [HSO4]) as compared to [DMIM] [OH] (5.387 eV).

Reversible phase transition in vanadium oxide films sputtered on metal substrates

NASA Astrophysics Data System (ADS)

Palai, Debajyoti; Carmel Mary Esther, A.; Porwal, Deeksha; Pradeepkumar, Maurya Sandeep; Raghavendra Kumar, D.; Bera, Parthasarathi; Sridhara, N.; Dey, Arjun

2016-11-01

Vanadium oxide films, deposited on aluminium (Al), titanium (Ti) and tantalum (Ta) metal substrates by pulsed RF magnetron sputtering at a working pressure of 1.5 x10-2 mbar at room temperature are found to display mixed crystalline vanadium oxide phases viz., VO2, V2O3, V2O5. The films have been characterized by field-emission scanning electron microscopy, X-ray diffraction, differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy, and their thermo-optical and electrical properties have been investigated. Studies of the deposited films by DSC have revealed a reversible-phase transition found in the temperature range of 45-49 °C.

Organometalic carbosilane polymers containing vanadium and their preparation

NASA Technical Reports Server (NTRS)

Yajima, S.; Okamura, K.; Shishido, T.; Fukuda, K.

1983-01-01

The present invention concerns a new organometallic polymer material containing in part a vanadium-siloxane linkage (V-0-Si), which has excellent resistance to heat and oxidation and a high residue ratio after high temperature treatment in a non-oxidizing atmosphere, for example, nitrogen, argon, helium, ammonia, or hydrogen.

Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime-Based Adsorbents in Natural Seawater

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

Kuo, Li-Jung; Gill, Gary A.; Tsouris, Costas

The apparent enthalpy and entropy of the complexation of uranium (VI) and vanadium (V) with amidoxime ligands grafted onto polyethylene fiber was determined using time series measurements of adsorption capacities in natural seawater at three different temperatures. The complexation of uranium was highly endothermic, while the complexation of vanadium showed minimal temperature sensitivity. Amidoxime-based polymeric adsorbents exhibit significantly increased uranium adsorption capacities and selectivity in warmer waters.

Comparison of the optical responses of O-poor and O-rich thermochromic VOX films during semiconductor-to-metal transition

NASA Astrophysics Data System (ADS)

Luo, Zhenfei; Wu, Zhiming; Wang, Tao; Xu, Xiangdong; Li, Weizhi; Li, Wei; Jiang, Yadong

2012-09-01

O-poor and O-rich thermochromic vanadium oxide (VOX) nanostructured thin films were prepared by applying reactive direct current magnetron sputtering and post-annealing in oxygen ambient. UV-visible spectrophotometer and spectroscopic ellipsometry were used to investigate the optical properties of films. It was found that, when the O-poor VOX thin film underwent semiconductor-to-metal transition, the values of optical conductivity and extinction coefficient in the visible region increased due to the existence of occupied band-gap states. This noticeable feature, however, was not observed for the O-rich film, which showed a similar optical behavior with the stoichiometric crystalline VO2 films reported in the literatures. Moreover, the O-poor VOX film exhibits consistent variations of transmission values in the visible/near-infrared region when it undergoes semiconductor-to-metal transition.

Fabrication of photocatalytically active vanadium oxide nanostructures via plasma route

NASA Astrophysics Data System (ADS)

Kajita, Shin; Yoshida, Tomoko; Ohno, Noriyasu; Ichino, Yusuke; Yoshida, Naoaki

2018-05-01

Plasma irradiation was used to create nanostructured vanadium oxide with potential commercial and industrial applications. Morphology changes were induced at the nano- and micro-meter scale, accompanied by the growth of helium nanobubbles. Micrometer-sized pillars, cube-shaped nanostructures, and fuzzy fiberform nanostructures were grown on the surface; the necessary conditions in terms of the incident ion energy and the surface temperature for those morphology changes were revealed. Hydrogen production experiments using a photocatalytic reaction with aqueous methanol solution were conducted on the fabricated samples. Enhanced H2 production was confirmed with the plasma irradiated nanostructured sample that had been oxidized in air atmosphere. Photocatalytically inactive vanadium oxide exhibited a high photocatalytic activity after nanostructurization of the surface by helium plasma irradiation.

A new electrocatalyst and its application method for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Wei, Guanjie; Jing, Minghua; Fan, Xinzhuang; Liu, Jianguo; Yan, Chuanwei

2015-08-01

The edge plane in carbon structure has good electrocatalytic activity toward vanadium redox reaction. To apply it in vanadium redox flow battery (VRFB) practically, the graphite nanopowders (GNPs) containing amounts of edge planes are used as electrocatalyst and embedded in the electrospun carbon nanofibers (ECNFs) by different mass ratios to make composite electrodes. The morphology and electrochemical activity of the GNPs and the composite electrodes containing them are characterized. Compared with the pristine ECNFs, the composite electrodes show much higher electrochemical activity. With the increase of GNPs content in composite electrodes, the electrochemical reversibility of the vanadium redox couples also increases. It proves the addition of GNPs can surely improve the electrochemical activity of ECNFs. Among the composite electrodes, the ECNFs containing 30 nm GNP by mass ratio of 1:50 show the best electrochemical activity, largest active surface area and excellent stability. Due to the high performance of GNP/ECNFs composite electrode and its relatively low cost preparation process, the GNPs are expected to be used as electrocatalyst in VRFB on a large scale to improve the cell performance.

Insight into the adsorption mechanisms of vanadium(V) on a high-efficiency biosorbent (Ti-doped chitosan bead).

PubMed

Liu, Xin; Zhang, Lingfan

2015-08-01

In this present study, a new chitosan bead modified with titanium ions (TiCB) was prepared and employed for the adsorption of vanadium ions from aqueous solutions. Batch adsorption experiments were performed to research the effect of various factors, including pH, temperature, contact time and initial concentration of vanadium(V) ions. The adsorption of vanadium was followed by the pseudo second-order kinetic and the Langmuir isotherm model, with a remarkable maximum adsorption capacity of 210 mg/g. The analysis of thermodynamic parameters (ΔG°, ΔH° and ΔS°) revealed that the nature of adsorption was feasible, spontaneous (ΔG°<0) and endothermic (ΔH°>0) process. FTIR, EDS, EMI and XPS studies suggested that the mechanisms of adsorption were possibly attributed to electrostatic attraction, ligand-exchange and redox reaction between TiCB and vanadium ions. Copyright © 2015 Elsevier B.V. All rights reserved.

Deposition and characterization of vanadium oxide based thin films for MOS device applications

NASA Astrophysics Data System (ADS)

Rakshit, Abhishek; Biswas, Debaleen; Chakraborty, Supratic

2018-04-01

Vanadium Oxide films are deposited on Si (100) substrate by reactive RF-sputtering of a pure Vanadium metallic target in an Argon-Oxygen plasma environment. The ratio of partial pressures of Argon to Oxygen in the sputtering-chamber is varied by controlling their respective flow rates and the resultant oxide films are obtained. MOS Capacitor based devices are then fabricated using the deposited oxide films. High frequency Capacitance-Voltage (C-V) and gate current-gate voltage (I-V) measurements reveal a significant dependence of electrical characteristics of the deposited films on their sputtering deposition parameters mainly, the relative content of Argon/Oxygen in the plasma chamber. A noteworthy change in the electrical properties is observed for the films deposited under higher relative oxygen content in the plasma atmosphere. Our results show that reactive sputtering serves as an indispensable deposition-setup for fabricating vanadium oxide based MOS devices tailor-made for Non-Volatile Memory (NVM) applications.

Stability of rhombohedral phases in vanadium at high-pressure and high-temperature: first-principles investigations

NASA Astrophysics Data System (ADS)

Wang, Yi X.; Wu, Q.; Chen, Xiang R.; Geng, Hua Y.

2016-09-01

The pressure-induced transition of vanadium from BCC to rhombohedral structures is unique and intriguing among transition metals. In this work, the stability of these phases is revisited by using density functional theory. At finite temperatures, a novel transition of rhombohedral phases back to BCC phase induced by thermal electrons is discovered. This reentrant transition is found not driven by phonons, instead it is the electronic entropy that stabilizes the latter phase, which is totally out of expectation. Parallel to this transition, we find a peculiar and strong increase of the shear modulus C44 with increasing temperature. It is counter-intuitive in the sense that it suggests an unusual harding mechanism of vanadium by temperature. With these stability analyses, the high-pressure and finite-temperature phase diagram of vanadium is proposed. Furthermore, the dependence of the stability of RH phases on the Fermi energy and chemical environment is investigated. The results demonstrate that the position of the Fermi level has a significant impact on the phase stability, and follows the band-filling argument. Besides the Fermi surface nesting, we find that the localization/delocalization of the d orbitals also contributes to the instability of rhombohedral distortions in vanadium.

Arsenic, vanadium, iron, and manganese biogeochemistry in a deltaic wetland, southern Louisiana, USA

DOE PAGES

Telfeyan, Katherine; Breaux, Alexander; Kim, Jihyuk; ...

2017-04-05

Geochemical cycling of the redox-sensitive trace elements arsenic (As) and vanadium (V) was examined in shallow pore waters from a marsh in an interdistributary embayment of the lower Mississippi River Delta. In particular, we explore how redox changes with depth and distance from the Mississippi River affect As and V cycling in the marsh pore waters. Previous geophysical surveys and radon mass balance calculations suggested that Myrtle Grove Canal and bordering marsh receive fresh groundwater, derived in large part from seepage of the Mississippi River, which subsequently mixes with brackish waters of Barataria Bay. In addition, the redox geochemistry ofmore » pore waters in the wetlands is affected by Fe and S cycling in the shallow subsurface (0-20 cm). Sediments with high organic matter content undergo SO 4 2- reduction, a process ubiquitous in the shallow subsurface but largely absent at greater depths (~3 m). Instead, at depth, in the absence of organic-rich sediments, Fe concentrations are elevated, suggesting that reduction of Fe(III) oxides/oxyhydroxides buffers redox conditions. Arsenic and V cycling in the shallow subsurface are decoupled from their behavior at depth, where both V and As appear to be removed from solution by either diffusion or adsorption onto, or co-precipitation with, authigenic minerals within the deeper aquifer sediments. Pore water As concentrations are greatest in the shallow subsurface (e.g., up to 315 nmol kg -1 in the top ~20 cm of the sediment) but decrease with depth, reaching values <30 nmol kg -1 at depths between 3 and 4 m. Vanadium concentrations appear to be tightly coupled to Fe cycling in the shallow subsurface, but at depth, V may be adsorbed to clay or sedimentary organic matter (SOM). Diffusive fluxes are calculated to examine the export of trace elements from the shallow marsh pore waters to the overlying canal water that floods the marsh. The computed fluxes suggest that the shallow sediment serves as a source of

Arsenic, vanadium, iron, and manganese biogeochemistry in a deltaic wetland, southern Louisiana, USA

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

Telfeyan, Katherine; Breaux, Alexander; Kim, Jihyuk

Geochemical cycling of the redox-sensitive trace elements arsenic (As) and vanadium (V) was examined in shallow pore waters from a marsh in an interdistributary embayment of the lower Mississippi River Delta. In particular, we explore how redox changes with depth and distance from the Mississippi River affect As and V cycling in the marsh pore waters. Previous geophysical surveys and radon mass balance calculations suggested that Myrtle Grove Canal and bordering marsh receive fresh groundwater, derived in large part from seepage of the Mississippi River, which subsequently mixes with brackish waters of Barataria Bay. In addition, the redox geochemistry ofmore » pore waters in the wetlands is affected by Fe and S cycling in the shallow subsurface (0-20 cm). Sediments with high organic matter content undergo SO 4 2- reduction, a process ubiquitous in the shallow subsurface but largely absent at greater depths (~3 m). Instead, at depth, in the absence of organic-rich sediments, Fe concentrations are elevated, suggesting that reduction of Fe(III) oxides/oxyhydroxides buffers redox conditions. Arsenic and V cycling in the shallow subsurface are decoupled from their behavior at depth, where both V and As appear to be removed from solution by either diffusion or adsorption onto, or co-precipitation with, authigenic minerals within the deeper aquifer sediments. Pore water As concentrations are greatest in the shallow subsurface (e.g., up to 315 nmol kg -1 in the top ~20 cm of the sediment) but decrease with depth, reaching values <30 nmol kg -1 at depths between 3 and 4 m. Vanadium concentrations appear to be tightly coupled to Fe cycling in the shallow subsurface, but at depth, V may be adsorbed to clay or sedimentary organic matter (SOM). Diffusive fluxes are calculated to examine the export of trace elements from the shallow marsh pore waters to the overlying canal water that floods the marsh. The computed fluxes suggest that the shallow sediment serves as a source of

Atomic site preferences and structural evolution in vanadium-doped ZrSiO4 from multinuclear solid-state NMR

NASA Astrophysics Data System (ADS)

Dajda, N.; Dixon, J. M.; Smith, M. E.; Carthey, N.; Bishop, P. T.

2003-01-01

Solid state NMR spectra of 29Si are reported from pure and vanadium-doped zircon (V-ZrSiO4) samples. The vanadium concentration is varied up to ˜1-mol % V4+ by using both conventional-firing and sol-gel routes, and 51V NMR data are also recorded. 17O NMR of 17O isotopically enriched samples shows that the initial gel is completely amorphous with the whole range of possible M-O-M' linkages detected, and that this structure evolves into a fully ordered ZrSiO4 structure with calcination. Static 91Zr NMR data is reported from a pure zircon sample. The NMR data are used to quantify the amount of vanadium entering the zircon structure, and to elucidate its site preference within the lattice. Two contact shifted peaks with very different T1 relaxation from the main zircon peak but attributable to the zircon lattice are observed in the 29Si NMR spectra for all samples. These spectra are consistent with vanadium substitution on both the tetrahedral and dodecahedral sites, with a slight preference for the silicon site. The data show that the relative occupation of these two sites is almost independent of the preparation method and vanadium concentration. At a higher vanadium concentration a third additional peak is observed which may indicate another substitution site. Variable temperature NMR and susceptibility measurements indicate the hyperfine nature of the interactions influencing silicon from V4+ ions in the different sites.

The Deterioration Seen in Myelin Related Morphophysiology in Vanadium Exposed Rats is Partially Protected by Concurrent Iron Deficiency.

PubMed

Usende, Ifukibot Levi; Leitner, Dominque F; Neely, Elizabeth; Connor, James R; Olopade, James O

2016-08-30

Oligodendrocyte development and myelination occurs vigorously during the early post natal period which coincides with the period of peak mobilization of iron. Oligodendrocyte progenitor cells (OPCs) are easily disturbed by any agent that affects iron homeostasis and its assimilation into these cells. Environmental exposure to vanadium, a transition metal can disrupt this iron homeostasis. We investigated the interaction of iron deficiency and vanadium exposure on the myelination infrastructure and its related neurobehavioural phenotypes, and neurocellular profiles in developing rat brains. Control group (C) dams were fed normal diet while Group 2 (V) dams were fed normal diet and pups were injected with 3mg/kg body weight of sodium metavanadate daily from postnatal day (PND) 1-21. Group 3 (I+V) dams were fed iron deficient diet after delivery and pups injected with 3mg/kg body weight sodium metavanadate from PND1-21. Body and brain weights deteriorated in I+V relative to C and V while neurobehavioral deficit occurred more in V. Whereas immunohistochemical staining shows more astrogliosis and microgliosis indicative of neuroinflammation in I+V, more intense OPCs depletion and hypomyelination were seen in the V, and this was partially protected in I+V. In in vitro studies, vanadium induced glial cells toxicity was partially protected only at the LD 50 dose with the iron chelator, desferroxamine. The data indicate that vanadium promotes myelin damage and iron deficiency in combination with vanadium partially protects this neurotoxicological effects of vanadium.

Removal of vanadium from industrial wastewater using iron sorbents in batch and continuous flow pilot systems.

PubMed

Leiviskä, Tiina; Khalid, Muhammad Kamran; Sarpola, Arja; Tanskanen, Juha

2017-04-01

This study investigated the removal of vanadium from real industrial wastewater by using six iron materials: commercial iron sorbent (CFH-12), commercial mineral sorbent (AQM), blast furnace sludge (BFS), steel converter sludge (SCS), ferrochrome slag (FeCr) and slag from a steel foundry (OKTO). Batch tests revealed that CFH-12 (ferric oxyhydroxide) removed vanadium most efficiently, which was explained by its high iron content and the amorphous form of the iron, and that the sorption followed the Langmuir isotherm. With a dosage of 10 g/l and an initial vanadium concentration of 58.2 mg/l, 91-94% removal rates for vanadium were achieved in the studied pH range (3-9). Other sorbents showed significantly lower efficiency than CFH-12, with the exception of BFS at acidic pH (93%). Based on the batch test results, CFH-12 was selected for a pilot study made on site. The pilot study demonstrated the feasibility of CFH-12 to remove vanadium at high temperature (80 °C) from concentrated industrial wastewater with fluctuating water quality (vanadium concentration varied from 51 to 83 mg/l, pH about 9 (at 25 °C)). Leaching of impurities (mainly S, Ca, Mg and K) into the effluent occurred during the first day, but subsequently good quality effluent was produced (e.g. <0.1 mg/l V). During the pilot study, the amorphous iron material of CFH-12 was crystallized into a hematite-like phase (Fe 1.67 H 0.99 O 3 ), and goethite (FeO(OH)) with a higher average pore diameter, probably due to the hot process conditions to which CFH-12 was exposed for over five days. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vanadium oxide thin films produced by magnetron sputtering from a V2O5 target at room temperature

NASA Astrophysics Data System (ADS)

de Castro, Marcelo S. B.; Ferreira, Carlos L.; de Avillez, Roberto R.

2013-09-01

Vanadium oxide thin films were grown by RF magnetron sputtering from a V2O5 target at room temperature, an alternative route of production of vanadium oxide thin films for infrared detector applications. The films were deposited on glass substrates, in an argon-oxygen atmosphere with an oxygen partial pressure from nominal 0% to 20% of the total pressure. X-ray diffraction (XRD) and X-ray photon spectroscopy (XPS) analyses showed that the films were a mixture of several vanadium oxides (V2O5, VO2, V5O9 and V2O3), which resulted in different colors, from yellow to black, depending on composition. The electrical resistivity varied from 1 mΩ cm to more than 500 Ω cm and the thermal coefficient of resistance (TCR), varied from -0.02 to -2.51% K-1. Computational thermodynamics was used to simulate the phase diagram of the vanadium-oxygen system. Even if plasma processes are far from equilibrium, this diagram provides the range of oxygen pressures that lead to the growth of different vanadium oxide phases. These conditions were used in the present work.

Microbial Reduction and Precipitation of Vanadium by Shewanella oneidensis

PubMed Central

Carpentier, W.; Sandra, K.; De Smet, I.; Brigé, A.; De Smet, L.; Van Beeumen, J.

2003-01-01

Shewanella oneidensis couples anaerobic oxidation of lactate, formate, and pyruvate to the reduction of vanadium pentoxide (VV). The bacterium reduces VV (vanadate ion) to VIV (vanadyl ion) in an anaerobic atmosphere. The resulting vanadyl ion precipitates as a VIV-containing solid. PMID:12788772

A novel process for comprehensive utilization of vanadium slag

NASA Astrophysics Data System (ADS)

Liu, Li-ying; Du, Tao; Tan, Wen-jun; Zhang, Xin-pu; Yang, Fan

2016-02-01

Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas, which cause serious environmental problems. In this study, a new process for the comprehensive utilization of vanadium slag was proposed, wherein zeolite A and a V2O5/TiO2 system were synthesized. The structural properties of the as-synthesized zeolite A and the V2O5/TiO2 system were characterized using various experimental techniques, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and infrared spectroscopy. The results reveal that zeolite A and the V2O5/TiO2 system are successfully obtained with high purity. The results of gas adsorption measurements indicate that the prepared zeolite A exhibits high selectivity for CO2 over N2 and is a candidate material for CO2 capture from flue-gas streams.

Global phylogeography of the widely introduced North West Pacific ascidian Styela clava.

PubMed

Goldstien, Sharyn J; Dupont, Lise; Viard, Frédérique; Hallas, Paul J; Nishikawa, Teruaki; Schiel, David R; Gemmell, Neil J; Bishop, John D D

2011-02-22

The solitary ascidian Styela clava Herdman, 1882 is considered to be native to Japan, Korea, northern China and the Russian Federation in the NW Pacific, but it has spread globally over the last 80 years and is now established as an introduced species on the east and west coasts of North America, Europe, Australia and New Zealand. In eastern Canada it reaches sufficient density to be a serious pest to aquaculture concerns. We sequenced a fragment of the cytochrome oxidase subunit I mitochondrial gene (COI) from a total of 554 individuals to examine the genetic relationships of 20 S. clava populations sampled throughout the introduced and native ranges, in order to investigate invasive population characteristics. The data presented here show a moderate level of genetic diversity throughout the northern hemisphere. The southern hemisphere (particularly New Zealand) displays a greater amount of haplotype and nucleotide diversity in comparison. This species, like many other invasive species, shows a range of genetic diversities among introduced populations independent of the age of incursion. The successful establishment of this species appears to be associated with multiple incursions in many locations, while other locations appear to have experienced rapid expansion from a potentially small population with reduced genetic diversity. These contrasting patterns create difficulties when attempting to manage and mitigate a species that continues to spread among ports and marinas around the world.

Live imaging of fluorescent proteins in chordate embryos: from ascidians to mice.

PubMed

Passamaneck, Yale J; Di Gregorio, Anna; Papaioannou, Virginia E; Hadjantonakis, Anna-Katerina

2006-03-01

Although we have advanced in our understanding of the molecular mechanisms intrinsic to the morphogenesis of chordate embryos, the question of how individual developmental events are integrated to generate the final morphological form is still unresolved. Microscopic observation is a pivotal tool in developmental biology, both for determining the normal course of events and for contrasting this with the results of experimental and pathological perturbations. Since embryonic development takes place in three dimensions over time, to fully understand the events required to build an embryo we must investigate embryo morphogenesis in multiple dimensions in situ. Recent advances in the isolation of naturally fluorescent proteins, and the refinement of techniques for in vivo microscopy offer unprecedented opportunities to study the cellular and molecular events within living, intact embryos using optical imaging. These technologies allow direct visual access to complex events as they happen in their native environment, and thus provide greater insights into cell behaviors operating during embryonic development. Since most fluorescent protein probes and modes of data acquisition are common across species, we have chosen the mouse and the ascidian, two model organisms at opposite ends of the chordate clade, to review the use of some of the current genetically-encoded fluorescent proteins and their visualization in vivo in living embryos for the generation of high-resolution imaging data. Microsc. Res. Tech. 69:160-167, 2006. (c) 2006 Wiley-Liss, Inc.

Adverse Effect of Antifouling Compounds on the Reproductive Mechanisms of the Ascidian Ciona intestinalis

PubMed Central

Gallo, Alessandra; Tosti, Elisabetta

2013-01-01

Fertilization and embryo development that occur in sea water are sensitive to xenobiotics from anthropogenic sources. In this work, we evaluated the influence of two antifouling biocides, tributyltin (TBT) and diuron, on the reproductive mechanisms of the marine invertebrate Ciona intestinalis. By using electrophysiological techniques, we examined the impact of these compounds on the electrical properties of the mature oocytes and of events occurring at fertilization. With different toxicity assays, we studied the effect of the two biocides on the gametes by evaluating fertilization rate and embryo development. Results show that sodium (Na+) currents were significantly reduced by either of the two biocides, whereas conductance was significantly increased. The fertilization current frequency and amplitude, fertilization rate and larval development were affected only by TBT. This study suggests that: (i) the two biocides affect either the electrical properties of the oocyte plasma membrane and the reproductive success representing a risk factor for the survival of the species exposed to environmental pollution; (ii) the ascidian Ciona intestinalis may represent a good model organism to test toxicity of marine pollutants. Possible mechanisms of action of the two biocides are discussed. PMID:24065165

Application of Novel Anion-Exchange Blend Membranes (AEBMs) to Vanadium Redox Flow Batteries.

PubMed

Cho, Hyeongrae; Krieg, Henning M; Kerres, Jochen A

2018-06-19

Both cation-exchange membranes and anion-exchange membranes are used as ion conducting membranes in vanadium redox flow batteries (VRFBs). Anion-exchange membranes (AEMs) are applied in vanadium redox flow batteries due to the high blocking property of vanadium ions via the Donnan exclusion effect. In this study, novel anion-exchange blend membranes (AEBMs) were prepared, characterized, and applied in VRFBs. Bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide), poly[(1-(4,4′-diphenylether)-5-oxybenzimidazole)-benzimidazole] (PBI-OO) and sulfonated polyether sulfone polymer were combined to prepare 3-component AEBMs with 1,2,4,5-tetramethylimidazole (TMIm) for quaternization. 3-component AEBMs showed significantly enhanced chemical and mechanical properties compared with those of 2-component AEBMs, resulting in an improved performance in VRFBs. The compositions of the anion-exchange polymers in 3-component AEBMs were systematically varied to optimize the AEBMs for the redox-flow battery application. While the 3-component AEBMs showed comparable efficiencies with Nafion ® 212 membranes, they displayed improved vanadium ions cross-over as was confirmed by open circuit voltage tests and capacity fade tests conducted in VRFBs. In addition, one of the synthesized 3-component AEBM had a superior coulombic efficiency and capacity retention in a charging⁻discharging test over 300 cycles at a current density of 40 mA/cm². It can thus be concluded that 3-component AEBMs are promising candidates for long-term operation in VRFBs.

Corrosion resistance investigation of vanadium alloys in liquid lithium

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

Borovitskaya, I. V., E-mail: symp@imet.ac.ru; Lyublinskiy, I. E.; Bondarenko, G. G.

A major concern in using vanadium alloys for first wall/blanket systems in fusion reactors is their activity with regard to nonmetallic impurities in the coolants. This paper presents the results of studying the corrosion resistance in high-purity liquid lithium (with the nitrogen and carbon content of less than 10{sup –3} wt %) of vanadium and vanadium alloys (V–1.86Ga, V–3.4Ga–0.62Si, V–4.81Ti–4.82Cr) both in the initial state and preliminarily irradiated with Ar+ ions with energy of 20 keV to a dose of 10{sup 22} m{sup –2} at an irradiation temperature of ~400°C. The degree of corrosion was estimated by measuring the changesmore » in the weight and microhardness. Corrosion tests were carried out under static isothermal conditions at a temperature of 600°C for 400 h. The identity of corrosion mechanisms of materials both irradiated with Ar ions and not irradiated, which consisted in an insignificant penetration of nitrogen into the materials and a substantial escape of oxygen from the materials, causing the formation of a zone with a reduced microhardness near the surface, was established. The influence of the corrosive action of lithium on the surface morphology of the materials under study was found, resulting in the manifestation of grain boundaries and slip lines on the sample surface, the latter being most clearly observed in the case of preliminary irradiation with Ar ions.« less

Electrochemical behaviour of vanadium(V)/vanadium(IV) redox couple at graphite electrodes

NASA Astrophysics Data System (ADS)

Zhong, S.; Skyllas-Kazacos, M.

The electrochemical behaviour of the V(V)/V(IV) couple has been studied at a graphite disc electrode in sulfuric acid using both cyclic and rotating-disc voltammetry. The results from the latter technique have revealed that the cathodic and anodic characteristics of this redox couple are quite different. The diffusion coefficient for V(IV), 2.14×10-6 cm2 s-1, is independent of the vanadium concentration. For V(IV) oxidation, the electrode kinetic parameters i0 and α have values of 2.47×10-4 A cm-2 and 0.71, respectively. The exchange current density, i0, for the V(V)/V(IV) reaction has been obtained at both graphite felt and reticulated vitreous carbon electrodes.

Removal of Vanadium(III) and Molybdenum(V) from Wastewater Using Posidonia oceanica (Tracheophyta) Biomass

PubMed Central

Pennesi, Chiara; Totti, Cecilia; Beolchini, Francesca

2013-01-01

The use of dried and re-hydrated biomass of the seagrass Posidonia oceanica was investigated as an alternative and –low-cost biomaterial for removal of vanadium(III) and molybdenum(V) from wastewaters. Initial characterisation of this biomaterial identified carboxylic groups on the cuticle as potentially responsible for cation sorption, and confirmed the toxic-metal bioaccumulation. The combined effects on biosorption performance of equilibrium pH and metal concentrations were investigated in an ideal single-metal system and in more real-life multicomponent systems. There were either with one metal (vanadium or molybdenum) and sodium nitrate, as representative of high ionic strength systems, or with the two metals (vanadium and molybdenum). For the single-metal solutions, the optimum was at pH 3, where a significant proportion of vanadium was removed (ca. 70%) while there was ca. 40% adsorption of molybdenum. The data obtained from the more real-life multicomponent systems showed that biosorption of one metal was improved both by the presence of the other metal and by high ionic strength, suggesting a synergistic effect on biosorption rather than competition. There data ware used for the development of a simple multi-metal equilibrium model based on the non-competitive Langmuir approach, which was successfully fitted to experimental data and represents a useful support tool for the prediction of biosorption performance in such real-life systems. Overall, the results suggest that biomass of P. oceanica can be used as an efficient biosorbent for removal of vanadium(III) and molybdenum(V) from aqueous solutions. This process thus offers an eco-compatible solution for the reuse of the waste material of leaves that accumulate on the beach due to both human activities and to storms at sea. PMID:24204692

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

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

Tang, Zhijiang; Lawton, Jamie S.; Sun, Che-Nan

2014-09-03

Here, sulfonated Diels-Alder poly(phenylene) (SDAPP) membranes were synthesized and characterized as potential electrolyte separators for vanadium redox flow batteries. The SDAPP membranes studied had ion exchange capacities of 1.4, 1.8 and 2.3 meq/g. Transmission electron microscopy imaging shows that the ionic domains in SDAPP are roughly 0.5 nm in dimension, while Nafion has a hydrophilic phase width of around 5 nm. The sulfuric acid uptake by SDAPP was higher than that for Nafion, but the materials had similar water uptake from solutions of various sulfuric acid concentrations. In equilibration with sulfuric acid concentrations ranging from 0–17.4 mol·kg -1, SDAPP withmore » a IEC of 2.3 meq/g had the highest conductivity, ranging from 0.21 to 0.05 S·cm -1, while SDAPP with a IEC of 1.8 had conductivity close to Nafion 117, ranging from 0.11 to 0.02 S·cm -1. With varying sulfuric acid concentration and temperature, vanadium permeability in SDAPP is positively correlated to the membrane's IEC. The vanadium permeability of SDAPP 2.3 is similar to that of Nafion, but permeability values for SDAPP 1.8 and SDAPP 1.4 are substantially lower. The vanadium permeation decreases with increasing electrolyte sulfuric acid concentration. Lastly, vanadium diffusion activation energy is about 20 kJ·mol -1 in both SDAPP and Nafion.« less

Cyclic Hexapeptide Dimers, Antatollamides A and B, from the Ascidian Didemnum molle. A Tryptophan-Derived Auxiliary for l- and d-Amino Acid Assignments.

PubMed

Salib, Mariam N; Molinski, Tadeusz F

2017-10-06

Two dimerized cyclic hexapeptides, antatollamides A (1) and B (2), were isolated from the colonial ascidian Didemnum molle collected in Pohnpei. The amino acid compositions and sequences were determined by interpretation of MS and 1D and 2D NMR data. Raney Ni reduction of antatollamide A cleaved the dimer to the corresponding monomeric cyclic hexapeptide with replacement of Cys by Ala. The amino acid configuration of 1 was established, after total hydrolysis, by derivatization with a new chiral reagent, (5-fluoro-2,4-dinitrophenyl)-N α -l-tryptophanamide (FDTA), prepared from l-Trp, followed by LCMS analysis; all amino acids were found to be l-configured except for d-Ala.

Distal Regeneration Involves the Age Dependent Activity of Branchial Sac Stem Cells in the Ascidian Ciona intestinalis.

PubMed

Jeffery, William R

2015-02-01

Tunicates have high capacities for regeneration but the underlying mechanisms and their relationship to life cycle progression are not well understood. Here we investigate the regeneration of distal structures in the ascidian tunicate Ciona intestinalis . Analysis of regenerative potential along the proximal-distal body axis indicated that distal organs, such as the siphons, their pigmented sensory organs, and the neural complex, could only be replaced from body fragments containing the branchial sac. Distal regeneration involves the formation of a blastema composed of cells that undergo cell proliferation prior to differentiation and cells that differentiate without cell proliferation. Both cell types originate in the branchial sac and appear in the blastema at different times after distal injury. Whereas the branchial sac stem cells are present in young animals, they are depleted in old animals that have lost their regeneration capacity. Thus Ciona adults contain a population of age-related stem cells located in the branchial sac that are a source of precursors for distal body regeneration.

IRIS Toxicological Review of Vanadium Pentoxide (External Review Draft)

EPA Science Inventory

This vanadium pentoxide reassessment consists of an oral reference dose (RfD), an inhalation reference concentration (RfC), an inhalation unit risk (IUR) and a cancer weight of evidence descriptor. This is the first assessment developing an RfC or IUR for this compound. This as...

Interactions of vanadium( iv ) with amidoxime ligands: redox reactivity

DOE PAGES

Parker, B. F.; Hohloch, S.; Pankhurst, J. R.; ...

2018-01-01

Vanadium is the main competitor for uranium extraction from seawater, and V( iv ) comprises a minor but important portion of this. V( iv ) undergoes redox reactions with oximes and amidoxime ligands under seawater-relevant conditions, leading to V( v ) complexes and loss of oxime functional groups.

Metal Accumulation and Vanadium-Induced Multidrug Resistance by Environmental Isolates of Escherichia hermannii and Enterobacter cloacae

PubMed Central

Hernández, Alicia; Mellado, Rafael P.; Martínez, José L.

1998-01-01

Contaminated soils from an oil refinery were screened for the presence of microorganisms capable of accumulating either nickel, vanadium, or both metals. Three strains of bacteria that belonged to the family Enterobacteriaceae were selected. Two of them were Escherichia hermannii strains, and outer membrane profile (OMP) analysis showed that they were similar to a strain of clinical origin; the other one was an Enterobacter cloacae strain that differed from clinical isolates. The selected bacteria accumulated both nickel and vanadium. Growth in the presence of vanadium induced multidrug resistance phenotypes in E. hermannii and E. cloacae. Incubation with this metal changed the OMP profile of E. hermannii but did not produce variations in the expression of the major OMPs of E. cloacae. PMID:9797283

A functionalized surface modification with vanadium nanoparticles of various valences against implant-associated bloodstream infection.

PubMed

Wang, Jiaxing; Zhou, Huaijuan; Guo, Geyong; Cheng, Tao; Peng, Xiaochun; Mao, Xin; Li, Jinhua; Zhang, Xianlong

2017-01-01

Bloodstream infection, especially with implants involved, is an often life-threatening condition with high mortality rates, imposing a heavy burden on patients and medical systems. Herein, we firstly deposited homogeneous vanadium metal, V 2 O 3 , VO 2 , and V 2 O 5 nanofilms on quartz glass by magnetron sputtering. Using these platforms, we further investigated the potential antimicrobial efficiency of these nano-VO x films and the interactions of human erythrocytes and bacteria (methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa ) with our samples in a novel cell-bacteria coculture model. It was demonstrated that these nano-VO x precipitated favorable antibacterial activity on both bacteria, especially on S. aureus , and this effect increased with higher vanadium valence. A possible mechanism accountable for these results might be elevated levels of vanadium-induced intracellular reactive oxygen species. More importantly, based on hemolysis assays, our nano-VO x films were found to be able to kill prokaryotic cells but were not toxic to mammalian cells, holding the potential for the prevention of implant-related hematogenous infections. As far as we know, this is the first report wherein such nano-VO x films have assisted human erythrocytes to combat bacteria in a valence-dependent manner. Additionally, vanadium ions were released from these nano-VO x films in a sustained manner, and low-valence films possessed better biocompatibility with human fibroblasts. This work may provide new insights for biomedical applications of inorganic vanadium compounds and attract growing attention in this field. From the perspective of surface modification and functionalization, this study holds promise to avail the prophylaxis of bloodstream infections involving implantable biomedical devices.

A functionalized surface modification with vanadium nanoparticles of various valences against implant-associated bloodstream infection

PubMed Central

Wang, Jiaxing; Zhou, Huaijuan; Guo, Geyong; Cheng, Tao; Peng, Xiaochun; Mao, Xin; Li, Jinhua; Zhang, Xianlong

2017-01-01

Bloodstream infection, especially with implants involved, is an often life-threatening condition with high mortality rates, imposing a heavy burden on patients and medical systems. Herein, we firstly deposited homogeneous vanadium metal, V2O3, VO2, and V2O5 nanofilms on quartz glass by magnetron sputtering. Using these platforms, we further investigated the potential antimicrobial efficiency of these nano-VOx films and the interactions of human erythrocytes and bacteria (methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa) with our samples in a novel cell–bacteria coculture model. It was demonstrated that these nano-VOx precipitated favorable antibacterial activity on both bacteria, especially on S. aureus, and this effect increased with higher vanadium valence. A possible mechanism accountable for these results might be elevated levels of vanadium-induced intracellular reactive oxygen species. More importantly, based on hemolysis assays, our nano-VOx films were found to be able to kill prokaryotic cells but were not toxic to mammalian cells, holding the potential for the prevention of implant-related hematogenous infections. As far as we know, this is the first report wherein such nano-VOx films have assisted human erythrocytes to combat bacteria in a valence-dependent manner. Additionally, vanadium ions were released from these nano-VOx films in a sustained manner, and low-valence films possessed better biocompatibility with human fibroblasts. This work may provide new insights for biomedical applications of inorganic vanadium compounds and attract growing attention in this field. From the perspective of surface modification and functionalization, this study holds promise to avail the prophylaxis of bloodstream infections involving implantable biomedical devices. PMID:28458535

Superconducting MgB2 wires with vanadium diffusion barrier

NASA Astrophysics Data System (ADS)

Hušek, I.; Kováč, P.; Melišek, T.; Kulich, M.; Rosová, A.; Kopera, L.; Szundiová, B.

2017-10-01

Single-core MgB2 wires with a vanadium barrier and Cu stabilization have been made by the in situ powder-in-tube (PIT) and internal magnesium diffusion (IMD) into boron processes. Heat treatment of PIT wires was done at the temperature range of 650 °C-850 °C/30 min. Critical currents of differently treated MgB2/V/Cu wires have been measured and related with the structure of MgB2. It was found that critical current density of MgB2/V wire annealed above 700 °C decreases rapidly. The obtained results clearly show that vanadium is a well formable metal and can be applied as an effective diffusion barrier for MgB2 wires heat-treated at temperatures ≤700 °C. This temperature limit is well applicable for MgB2 wires with high current densities made by PIT and also by the IMD process.

Highly stable pyridinium-functionalized cross-linked anion exchange membranes for all vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

2016-11-01

It has recently been demonstrated that the use of anion exchange membranes (AEMs) in vanadium redox flow batteries (VRFBs) can reduce the migration of vanadium ions through the membrane due to the Donnan exclusion effect among the positively charged functional groups and vanadium ions. However, AEMs are plagued by low chemical stability in harsh chemical environments. Here we propose and fabricate a pyridinium-functionalized cross-linked AEM for VRFBs. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. Therefore, the membrane exhibits littler decay in a harsh environment for 20 days during the course of an ex situ immersion test. A cycling test also demonstrates that the VRFB assembled with the membrane enable to retain 80% of the initial discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle-1. Meanwhile, the membrane also shows a low vanadium permeability and a reasonably high conductivity in supporting electrolytes. Hence, all the measurements and performance tests reported in this work suggest that the membrane is a promising AEM for redox flow batteries to achieve excellent cycling stability and superior cell performance.

Stability of rhombohedral phases in vanadium at high-pressure and high-temperature: first-principles investigations

PubMed Central

Wang, Yi X.; Wu, Q.; Chen, Xiang R.; Geng, Hua Y.

2016-01-01

The pressure-induced transition of vanadium from BCC to rhombohedral structures is unique and intriguing among transition metals. In this work, the stability of these phases is revisited by using density functional theory. At finite temperatures, a novel transition of rhombohedral phases back to BCC phase induced by thermal electrons is discovered. This reentrant transition is found not driven by phonons, instead it is the electronic entropy that stabilizes the latter phase, which is totally out of expectation. Parallel to this transition, we find a peculiar and strong increase of the shear modulus C44 with increasing temperature. It is counter-intuitive in the sense that it suggests an unusual harding mechanism of vanadium by temperature. With these stability analyses, the high-pressure and finite-temperature phase diagram of vanadium is proposed. Furthermore, the dependence of the stability of RH phases on the Fermi energy and chemical environment is investigated. The results demonstrate that the position of the Fermi level has a significant impact on the phase stability, and follows the band-filling argument. Besides the Fermi surface nesting, we find that the localization/delocalization of the d orbitals also contributes to the instability of rhombohedral distortions in vanadium. PMID:27581551

Electron affinity of cubic boron nitride terminated with vanadium oxide

NASA Astrophysics Data System (ADS)

Yang, Yu; Sun, Tianyin; Shammas, Joseph; Kaur, Manpuneet; Hao, Mei; Nemanich, Robert J.

2015-10-01

A thermally stable negative electron affinity (NEA) for a cubic boron nitride (c-BN) surface with vanadium-oxide-termination is achieved, and its electronic structure was analyzed with in-situ photoelectron spectroscopy. The c-BN films were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition employing BF3 and N2 as precursors. Vanadium layers of ˜0.1 and 0.5 nm thickness were deposited on the c-BN surface in an electron beam deposition system. Oxidation of the metal layer was achieved by an oxygen plasma treatment. After 650 °C thermal annealing, the vanadium oxide on the c-BN surface was determined to be VO2, and the surfaces were found to be thermally stable, exhibiting an NEA. In comparison, the oxygen-terminated c-BN surface, where B2O3 was detected, showed a positive electron affinity of ˜1.2 eV. The B2O3 evidently acts as a negatively charged layer introducing a surface dipole directed into the c-BN. Through the interaction of VO2 with the B2O3 layer, a B-O-V layer structure would contribute a dipole between the O and V layers with the positive side facing vacuum. The lower enthalpy of formation for B2O3 is favorable for the formation of the B-O-V layer structure, which provides a thermally stable surface dipole and an NEA surface.

Microbial reduction and precipitation of vanadium (V) in groundwater by immobilized mixed anaerobic culture.

PubMed

Zhang, Baogang; Hao, Liting; Tian, Caixing; Yuan, Songhu; Feng, Chuanping; Ni, Jinren; Borthwick, Alistair G L

2015-09-01

Vanadium is an important contaminant impacted by natural and industrial activities. Vanadium (V) reduction efficiency as high as 87.0% was achieved by employing immobilized mixed anaerobic sludge as inoculated seed within 12h operation, while V(IV) was the main reduction product which precipitated instantly. Increasing initial V(V) concentration resulted in the decrease of V(V) removal efficiency, while this index increased first and then decreased with the increase of initial COD concentration, pH and conductivity. High-throughput 16S rRNA gene pyrosequencing analysis indicated the decreased microbial diversity. V(V) reduction was realized through dissimilatory reduction process by significantly enhanced Lactococcus and Enterobacter with oxidation of lactic and acetic acids from fermentative microorganisms such as the enriched Paludibacter and the newly appeared Acetobacterium, Oscillibacter. This study is helpful to detect new functional species for V(V) reduction and constitutes a step ahead in developing in situ bioremediations of vanadium contamination. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Syntheses and Structure of the First Vanadium(IV) and Vanadium(V) Binary Azides, V(N3)4, [V(N3)6]2- and [V(N3)6]- (Preprint)

DTIC Science & Technology

2009-11-17

V(N3)3(N3S2)] 2- , [22] have been reported, and no binary vanadium(V) compounds had been known except for VF5, VF6 - and V2O5 . By analogy with...valves. Volatile materials were handled in a Pyrex glass or stainless steel/Teflon-FEP vacuum line. [31] All reaction vessels were passivated with ClF3...successful synthesis of the [V(N3)6] - anion, the only binary vanadium(V) compound known besides VF5, VF6 - and V2O5 . N1’ N8 N9 N1 N2 N3 V N4 N5 N6 N2

Deposition of vanadium oxide films by direct-current magnetron reactive sputtering

NASA Astrophysics Data System (ADS)

Kusano, E.; Theil, J. A.; Thornton, John A.

1988-06-01

It is demonstrated here that thin films of vanadium oxide can be deposited at modest substrate temperatures by dc reactive sputtering from a vanadium target in an O2-Ar working gas using a planar magnetron source. Resistivity ratios of about 5000 are found between a semiconductor phase with a resistivity of about 5 Ohm cm and a metallic phase with a resistivity of about 0.001 Ohm cm for films deposited onto borosilicate glass substrates at about 400 C. X-ray diffraction shows the films to be single-phase VO2 with a monoclinic structure. The VO2 films are obtained for a narrow range of O2 injection rates which correspond to conditions where cathode poisoning is just starting to occur.

Deposition of vanadium oxide films by direct-current magnetron reactive sputtering

NASA Technical Reports Server (NTRS)

Kusano, E.; Theil, J. A.; Thornton, John A.

1988-01-01

It is demonstrated here that thin films of vanadium oxide can be deposited at modest substrate temperatures by dc reactive sputtering from a vanadium target in an O2-Ar working gas using a planar magnetron source. Resistivity ratios of about 5000 are found between a semiconductor phase with a resistivity of about 5 Ohm cm and a metallic phase with a resistivity of about 0.001 Ohm cm for films deposited onto borosilicate glass substrates at about 400 C. X-ray diffraction shows the films to be single-phase VO2 with a monoclinic structure. The VO2 films are obtained for a narrow range of O2 injection rates which correspond to conditions where cathode poisoning is just starting to occur.

Defect-mediated room temperature ferromagnetism in vanadium dioxide thin films

NASA Astrophysics Data System (ADS)

Yang, Tsung-Han; Nori, Sudhakar; Zhou, Honghui; Narayan, Jagdish

2009-09-01

High quality epitaxial undoped vanadium oxide (VO2) thin films on c-plane sapphire (0001) substrate have been grown using pulsed laser deposition technique. The as-grown films exhibited excellent structural and transport properties without requiring further annealing treatments for these oxygen-deficient oxide films. The epitaxial growth has been achieved via domain matching epitaxy, where matching of integral multiples of planes occurs across the film-substrate interface. The magnetic properties of vanadium oxide (VO2) films investigated at different temperatures in the range of 10-360 K showed significant magnetic hysteresis as well as saturation of the magnetic moment. The origin of ferromagnetic properties with an estimated Curie temperature above 500 K is discussed in the absence of magnetic impurities in VO2 thin films as determined by x-ray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy.

Uncoupling binding of substrate CO from turnover by vanadium nitrogenase.

PubMed

Lee, Chi Chung; Fay, Aaron W; Weng, Tsu-Chien; Krest, Courtney M; Hedman, Britt; Hodgson, Keith O; Hu, Yilin; Ribbe, Markus W

2015-11-10

Biocatalysis by nitrogenase, particularly the reduction of N2 and CO by this enzyme, has tremendous significance in environment- and energy-related areas. Elucidation of the detailed mechanism of nitrogenase has been hampered by the inability to trap substrates or intermediates in a well-defined state. Here, we report the capture of substrate CO on the resting-state vanadium-nitrogenase in a catalytically competent conformation. The close resemblance of this active CO-bound conformation to the recently described structure of CO-inhibited molybdenum-nitrogenase points to the mechanistic relevance of sulfur displacement to the activation of iron sites in the cofactor for CO binding. Moreover, the ability of vanadium-nitrogenase to bind substrate in the resting-state uncouples substrate binding from subsequent turnover, providing a platform for generation of defined intermediate(s) of both CO and N2 reduction.

Environmental Control of Vanadium Haloperoxidases and Halocarbon Emissions in Macroalgae.

PubMed

Punitha, Thillai; Phang, Siew-Moi; Juan, Joon Ching; Beardall, John

2018-04-24

Vanadium-dependent haloperoxidases (V-HPO), able to catalyze the reaction of halide ions (Cl - , Br - , I - ) with hydrogen peroxide, have a great influence on the production of halocarbons, which in turn are involved in atmospheric ozone destruction and global warming. The production of these haloperoxidases in macroalgae is influenced by changes in the surrounding environment. The first reported vanadium bromoperoxidase was discovered 40 years ago in the brown alga Ascophyllum nodosum. Since that discovery, more studies have been conducted on the structure and mechanism of the enzyme, mainly focused on three types of V-HPO, the chloro- and bromoperoxidases and, more recently, the iodoperoxidase. Since aspects of environmental regulation of haloperoxidases are less well known, the present paper will focus on reviewing the factors which influence the production of these enzymes in macroalgae, particularly their interactions with reactive oxygen species (ROS).

Synthesis of nanostructured vanadium powder by high-energy ball milling: X-ray diffraction and high-resolution electron microscopy characterization

NASA Astrophysics Data System (ADS)

Krishnan, Vinoadh Kumar; Sinnaeruvadi, Kumaran

2016-10-01

Vanadium metal powders, ball milled with different surfactants viz., stearic acid, KCl and NaCl, have been studied by X-ray diffraction and transmission electron microscopy. The surfactants alter the microstructural and morphological characteristics of the powders. Ball milling with stearic acid results in solid-state amorphization, while powders milled with KCl yield vanadium-tungsten carbide nanocomposite mixtures. NaCl proved to be an excellent surfactant for obtaining nanostructured fusion-grade vanadium powders. In order to understand the reaction mechanism behind any interstitial addition in the ball-milled powders, CHNOS analysis was performed.

Friedel-Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery.

PubMed

Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

2013-12-30

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel-Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion.

Switching adhesion forces by crossing the metal–insulator transition in Magnéli-type vanadium oxide crystals

PubMed Central

Klemm, Matthias; Horn, Siegfried; Woydt, Mathias

2011-01-01

Summary Magnéli-type vanadium oxides form the homologous series VnO2 n -1 and exhibit a temperature-induced, reversible metal–insulator first order phase transition (MIT). We studied the change of the adhesion force across the transition temperature between the cleavage planes of various vanadium oxide Magnéli phases (n = 3 … 7) and spherical titanium atomic force microscope (AFM) tips by systematic force–distance measurements with a variable-temperature AFM under ultrahigh vacuum conditions (UHV). The results show, for all investigated samples, that crossing the transition temperatures leads to a distinct change of the adhesion force. Low adhesion corresponds consistently to the metallic state. Accordingly, the ability to modify the electronic structure of the vanadium Magnéli phases while maintaining composition, stoichiometry and crystallographic integrity, allows for relating frictional and electronic material properties at the nano scale. This behavior makes the vanadium Magnéli phases interesting candidates for technology, e.g., as intelligent devices or coatings where switching of adhesion or friction is desired. PMID:21977416

The Sexual and Mating System of the Shrimp Odontonia katoi (Palaemonidae, Pontoniinae), a Symbiotic Guest of the Ascidian Polycarpa aurata in the Coral Triangle

PubMed Central

Baeza, J. Antonio; Hemphill, Carrie A.; Ritson-Williams, Raphael

2015-01-01

Theory predicts that monogamy is adaptive in symbiotic crustaceans inhabiting relatively small and morphologically simple hosts in tropical environments where predation risk away from hosts is high. We tested this prediction in the shrimp Odontonia katoi, which inhabits the atrial chamber of the ascidian Polycarpa aurata in the Coral Triangle. Preliminary observations in O. katoi indicated that males were smaller than females, which is suggestive of sex change (protandry) in some symbiotic organisms. Thus, we first investigated the sexual system of O. katoi to determine if this shrimp was sequentially hermaphroditic. Morphological identification and size frequency distributions indicated that the population comprised males that, on average, were smaller than females. Gonad dissections demonstrated the absence of transitional individuals. Thus, O. katoi is a gonochoric species with reverse sexual dimorphism. The population distribution of O. katoi in its ascidian host did not differ significantly from a random distribution and shrimps inhabiting the same host individual as pairs were found with a frequency similar to that expected by chance alone. This is in contrast to that reported for other socially monogamous crustaceans in which pairs of heterosexual conspecifics are found in host individuals more frequently than expected by chance alone. Thus, the available information argues against monogamy in O. katoi. Furthermore, that a high frequency of solitary females were found brooding embryos and that the sex ratio was skewed toward females suggests that males might be roaming among hosts in search of receptive females in O. katoi. Symbiotic crustaceans can be used as a model system to understand the adaptive value of sexual and mating systems in marine invertebrates. PMID:25799577

Optimized anion exchange membranes for vanadium redox flow batteries.

PubMed

Chen, Dongyang; Hickner, Michael A; Agar, Ertan; Kumbur, E Caglan

2013-08-14

In order to understand the properties of low vanadium permeability anion exchange membranes for vanadium redox flow batteries (VRFBs), quaternary ammonium functionalized Radel (QA-Radel) membranes with three ion exchange capacities (IECs) from 1.7 to 2.4 mequiv g(-1) were synthesized and 55-60 μm thick membrane samples were evaluated for their transport properties and in-cell battery performance. The ionic conductivity and vanadium permeability of the membranes were investigated and correlated to the battery performance through measurements of Coulombic efficiency, voltage efficiency and energy efficiency in single cell tests, and capacity fade during cycling. Increasing the IEC of the QA-Radel membranes increased both the ionic conductivity and VO(2+) permeability. The 1.7 mequiv g(-1) IEC QA-Radel had the highest Coulombic efficiency and best cycling capacity maintenance in the VRFB, while the cell's voltage efficiency was limited by the membrane's low ionic conductivity. Increasing the IEC resulted in higher voltage efficiency for the 2.0 and 2.4 mequiv g(-1) samples, but the cells with these membranes displayed reduced Coulombic efficiency and faster capacity fade. The QA-Radel with an IEC of 2.0 mequiv g(-1) had the best balance of ionic conductivity and VO(2+) permeability, achieving a maximum power density of 218 mW cm(-2) which was higher than the maximum power density of a VRFB assembled with a Nafion N212 membrane in our system. While anion exchange membranes are under study for a variety of VRFB applications, this work demonstrates that the material parameters must be optimized to obtain the maximum cell performance.

Practical thermodynamic quantities for aqueous vanadium- and iron-based flow batteries

DOE PAGES

Hudak, Nicholas S.

2013-12-31

A simple method for experimentally determining thermodynamic quantities for flow battery cell reactions is presented. Equilibrium cell potentials, temperature derivatives of cell potential (d E/d T), Gibbs free energies, and entropies are reported here for all-vanadium, iron–vanadium, and iron–chromium flow cells with state-of-the-art solution compositions. Proof is given that formal potentials and formal temperature coefficients can be used with modified forms of the Nernst Equation to quantify the thermodynamics of flow cell reactions as a function of state-of-charge. Such empirical quantities can be used in thermo-electrochemical models of flow batteries at the cell or system level. In most cases, themore » thermodynamic quantities measured here are significantly different from standard values reported and used previously in the literature. The data reported here are also useful in the selection of operating temperatures for flow battery systems. Because higher temperatures correspond to lower equilibrium cell potentials for the battery chemistries studied here, it can be beneficial to charge a cell at higher temperature and discharge at lower temperature. As a result, proof-of-concept of improved voltage efficiency with the use of such non-isothermal cycling is given for the all-vanadium redox flow battery, and the effect is shown to be more pronounced at lower current densities.« less

Oxidation State Discrimination in the Atomic Layer Deposition of Vanadium Oxides

DOE PAGES

Weimer, Matthew S.; Kim, In Soo; Guo, Peijun; ...

2017-06-02

We describe the use of a vanadium 3+ precursor for atomic layer deposition (ALD) of thin films that span the common oxidation states of vanadium oxides. Self-limiting surface synthesis of V 2O 3, VO 2, and V 2O 5 are realized via four distinct reaction mechanisms accessed via judicious choice of oxygen ALD partners. In situ quartz crystal microbalance and quadrupole mass spectrometry were used to study the reaction mechanism of the vanadium precursor with O 3, H 2O 2, H 2O/O 2, and H 2O 2/H 2. A clear distinction between non-oxidative protic ligand exchange and metal oxidation ismore » demonstrated through sequential surface reactions with different non-metal precursors. This synergistic effect, provides greater control of the resultant metal species in the film, as well as reactive surface species during growth. In an extension of this approach, we introduce oxidation state control through reducing equivalents of H 2 gas. When H 2 is dosed after H 2O 2 during growth, amorphous films of VO 2 are deposited that are readily crystallized with a low temperature anneal. These VO 2 films show a temperature dependent Raman spectroscopy response in the expected range and consistent with the well-known phase-change behavior of VO 2.« less

Vanadium and tungsten release from V-based selective catalytic reduction diesel aftertreatment

NASA Astrophysics Data System (ADS)

Liu, Z. Gerald; Ottinger, Nathan A.; Cremeens, Christopher M.

2015-03-01

Vanadium-based selective catalytic reduction (V-SCR) catalysts are currently used for the reduction of nitrogen oxides (NOx) in worldwide diesel applications including Euro IV, V, and VI as well as U.S. nonroad Tier 4 Final. Although V-SCR catalysts are attractive because of their high NOx conversion, low cost, resistance to sulfur poisoning, and ability to reduce hydrocarbon emissions, there is concern that V-SCR washcoat material (e.g., vanadium and tungsten) and its derivatives may be released into the atmosphere, potentially harming human health and the environment. In this study, vanadium and tungsten release measurements are made with both a reactor- and engine-based approach in order to determine the potential release of these metals from diesel exhaust aftertreatment systems that contain a V-SCR catalyst. Results for a commercially available V-SCR reveal that both V and W release begin at 500 °C, and both reactor- and engine-based methods are capable of measuring qualitatively similar release. Emissions with the engine-based method are higher at all temperatures evaluated, likely due to this method's ability to capture particle-phase and vapor-phase emissions which become particle-bound after their evolution from the catalyst surface. Certification relevant data (NRTC and NRSC) from a nonroad engine is used to understand probable emissions from V-SCR aftertreatment architectures. Finally, results from a V-SCR catalyst formulated for improved thermal durability illustrate that it is possible to increase the maximum temperature for V-SCR catalysts. This comprehensive understanding of the temperature dependence of vanadium and tungsten volatility can be used to further analyze the full impact of diesel aftertreatment on exhaust emissions and their impact on human health and environmental toxicity.

Structural, optical and electrochemical properties of F-doped vanadium oxide transparent semiconducting thin films

NASA Astrophysics Data System (ADS)

Mousavi, M.; Khorrami, Gh. H.; Kompany, A.; Yazdi, Sh. Tabatabai

2017-12-01

In this study, F-doped vanadium oxide thin films with doping levels up to 60 at % were prepared by spray pyrolysis method on glass substrates. To measure the electrochemical properties, some films were deposited on fluorine-tin oxide coated glass substrates. The effect of F-doping on the structural, electrical, optical and electrochemical properties of vanadium oxide samples was investigated. The X-ray diffractographs analysis has shown that all the samples grow in tetragonal β-V2O5 phase structure with the preferred orientation of [200]. The intensity of (200) peak belonging to β-V2O5 phase was strongest in the undoped vanadium oxide film. The scanning electron microscopy images show that the samples have nanorod- and nanobelt-shaped structure. The size of the nanobelts in the F-doped vanadium oxide films is smaller than that in the pure sample and the width of the nanobelts increases from 30 to 70 nm with F concentration. With increasing F-doping level from 10 to 60 at %, the resistivity, the transparency and the optical band gap decrease from 111 to 20 Ω cm, 70 to 50% and 2.4 to 2.36 eV, respectively. The cyclic voltammogram (CV) results show that the undoped sample has the most extensive CV and by increasing F-doping level from 20 to 60 at %, the area of the CV is expanded. The anodic and cathodic peaks in F-doped samples are stronger.

Process optimization for diffusion bonding of tungsten with EUROFER97 using a vanadium interlayer

NASA Astrophysics Data System (ADS)

Basuki, Widodo Widjaja; Aktaa, Jarir

2015-04-01

Solid-state diffusion bonding is a selected joining technology to bond divertor components consisting of tungsten and EUROFER97 for application in fusion power plants. Due to the large mismatch in their coefficient of thermal expansions, which leads to serious thermally induced residual stresses after bonding, a thin vanadium plate is introduced as an interlayer. However, the diffusion of carbon originated from EUROFER97 in the vanadium interlayer during the bonding process can form a vanadium carbide layer, which has detrimental influences on the mechanical properties of the joint. For optimal bonding results, the thickness of this layer and the residual stresses has to be decreased sufficiently without a significant reduction of material transport especially at the vanadium/tungsten interface, which can be achieved by varying the diffusion bonding temperature and duration. The investigation results show that at a sufficiently low bonding temperature of 700 °C and a bonding duration of 4 h, the joint reaches a reasonable high ductility and toughness especially at elevated test temperature of 550 °C with elongation to fracture of 20% and mean absorbed Charpy impact energy of 2 J (using miniaturized Charpy impact specimens). The strength of the bonded materials is about 332 MPa at RT and 291 MPa at 550 °C. Furthermore, a low bonding temperature of 700 °C can also help to avoid the grain coarsening and the alteration of the grain structure especially of the EUROFER97 close to the bond interface.

Measurement of refractive indices of tunicates' tunics: light reflection of the transparent integuments in an ascidian Rhopalaea sp. and a salp Thetys vagina.

PubMed

Kakiuchida, Hiroshi; Sakai, Daisuke; Nishikawa, Jun; Hirose, Euichi

2017-01-01

Tunic is a cellulosic, integumentary matrix found in tunicates (Subphylum Tunicata or Urochordata). The tunics of some ascidian species and pelagic tunicates, such as salps, are nearly transparent, which is useful in predator avoidance. Transparent materials can be detected visually using light reflected from their surfaces, with the different refractive indices between two media, i.e., tunic and seawater, being the measure of reflectance. A larger difference in refractive indices thus provides a larger measure of reflectance. We measured the refractive indices of the transparent tunic of Thetys vagina (salp: Thaliacea) and Rhopalae a sp. (ascidian: Ascidiacea) using an Abbe refractometer and an ellipsometer to estimate the light reflection at the tunic surface and evaluate the anti-reflection effect of the nipple array structure on the tunic surface of T. vagina . At D-line light (λ = 589 nm), the refractive indices of the tunics were 0.002-0.004 greater than seawater in the measurements by Abbe refractometer, and 0.02-0.03 greater than seawater in the measurements by ellipsometer. The refractive indices of tunics were slightly higher than that of seawater. According to the simulation of light reflection based on rigorous coupled wave analysis (RCWA), light at a large angle of incidence will be completely reflected from a surface when its refractive indices are smaller than seawater. Therefore, the refractive index of integument is important for enabling transparent organisms to remain invisible in the water column. In order to minimize reflectance, the refractive index should be similar to, but never smaller than, that of the surrounding seawater. The simulation also indicated that the presence or absence of a nipple array does not cause significant difference in reflectance on the surface. The nipple array on the tunic of the diurnal salp may have another function, such as bubble repellence, other than anti-reflection.

Kinetic and Mechanism Study of Vanadium Acid Leaching from Black Shale Using Microwave Heating Method

NASA Astrophysics Data System (ADS)

Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

2018-04-01

The leaching kinetics of the vanadium leaching process were investigated by the comparison of microwave heating and conventional heating methods. Microwave heating with CaF2 had a synergistic effect and improved the vanadium leaching efficiency. In contrast to conventional heating leaching, microwave heating accelerated the vanadium leaching rate by approximately 1-3% and by approximately 15% when CaF2 was also used. The kinetics analysis showed that the calculated activation energy decreased in the microwave heating method in the presence and absence of CaF2. The control procedure of leaching also changed from a chemical reaction control step to a mixed chemical diffusion control step upon the addition of CaF2. Microwave heating was shown to be suitable for leaching systems with diffusion or mixed chemical diffusion control steps when the target mineral does not have a microwave absorbing ability.

A vanadium alloy for the application in a liquid metal blanket of a fusion reactor

NASA Astrophysics Data System (ADS)

Borgstedt, H. U.; Grundmann, M.; Konys, J.; Perić, Z.

1988-07-01

The vanadium alloy V3Ti1Si has been corrosion tested in liquid lithium and the eutectic alloy Pb-17Li at 550°C. This alloy has a comparable corrosion resistance to the alloy V15Cr5Ti in lithium. In this molten metal it is superior to stainless steel AISI 316. In the Pb-17Li melt it is even superior to martensitic steels. The alloy has only a weak tendency to be dissolved. It is sensitive to an exchange of non-metallic elements, which causes the formation of a hardened surface layer. These chemical effects are influenced by the mass and surface ratios of the vanadium alloy to the molten metals and other structural materials. These ratios are unfavorable in the two test loops. The effects might be less pronounced in a vanadium alloy/liquid metal fusion reactor blanket.

Simultaneous microbial and electrochemical reductions of vanadium (V) with bioelectricity generation in microbial fuel cells.

PubMed

Zhang, Baogang; Tian, Caixing; Liu, Ying; Hao, Liting; Liu, Ye; Feng, Chuanping; Liu, Yuqian; Wang, Zhongli

2015-03-01

Simultaneous microbial and electrochemical reductions of vanadium (V) with bioelectricity generation were realized in microbial fuel cells (MFCs). With initial V(V) concentrations of 75 mg/l and 150 mg/l in anolyte and catholyte, respectively, stable power output of 419±11 mW/m(2) was achieved. After 12h operation, V(V) concentration in the catholyte decreased to the value similar to that of the initial one in the anolyte, meanwhile it was nearly reduced completely in the anolyte. V(IV) was the main reduction product, which subsequently precipitated, acquiring total vanadium removal efficiencies of 76.8±2.9%. Microbial community analysis revealed the emergence of the new species of Deltaproteobacteria and Bacteroidetes as well as the enhanced Spirochaetes mainly functioned in the anode. This study opens new pathways to successful remediation of vanadium contamination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Kinetic and Mechanism Study of Vanadium Acid Leaching from Black Shale Using Microwave Heating Method

NASA Astrophysics Data System (ADS)

Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

2018-06-01

The leaching kinetics of the vanadium leaching process were investigated by the comparison of microwave heating and conventional heating methods. Microwave heating with CaF2 had a synergistic effect and improved the vanadium leaching efficiency. In contrast to conventional heating leaching, microwave heating accelerated the vanadium leaching rate by approximately 1-3% and by approximately 15% when CaF2 was also used. The kinetics analysis showed that the calculated activation energy decreased in the microwave heating method in the presence and absence of CaF2. The control procedure of leaching also changed from a chemical reaction control step to a mixed chemical diffusion control step upon the addition of CaF2. Microwave heating was shown to be suitable for leaching systems with diffusion or mixed chemical diffusion control steps when the target mineral does not have a microwave absorbing ability.

Hydrothermal Synthesis of Nanostructured Vanadium Oxides

PubMed Central

Livage, Jacques

2010-01-01

A wide range of vanadium oxides have been obtained via the hydrothermal treatment of aqueous V(V) solutions. They exhibit a large variety of nanostructures ranging from molecular clusters to 1D and 2D layered compounds. Nanotubes are obtained via a self-rolling process while amazing morphologies such as nano-spheres, nano-flowers and even nano-urchins are formed via the self-assembling of nano-particles. This paper provides some correlation between the molecular structure of precursors in the solution and the nanostructure of the solid phases obtained by hydrothermal treatment. PMID:28883325

Phonon triggered rhombohedral lattice distortion in vanadium at high pressure

DOE PAGES

Antonangeli, Daniele; Farber, Daniel L.; Bosak, Alexei; ...

2016-08-19

In spite of the simple body-centered-cubic crystal structure, the elements of group V, vanadium, niobium and tantalum, show strong interactions between the electronic properties and lattice dynamics. Further, these interactions can be tuned by external parameters, such as pressure and temperature. We used inelastic x-ray scattering to probe the phonon dispersion of single-crystalline vanadium as a function of pressure to 45 GPa. Our measurements show an anomalous high-pressure behavior of the transverse acoustic mode along the (100) direction and a softening of the elastic modulus C44 that triggers a rhombohedral lattice distortion occurring between 34 and 39 GPa. Lastly, ourmore » results provide the missing experimental confirmation of the theoretically predicted shear instability arising from the progressive intra-band nesting of the Fermi surface with increasing pressure, a scenario common to all transition metals of group V.« less

Assessment of the microstructure and torsional fatigue performance of an induction hardened vanadium microalloyed medium-carbon steel

NASA Astrophysics Data System (ADS)

Rothleutner, Lee M.

Vanadium microalloying of medium-carbon bar steels is a common practice in industry for a number of hot rolled as well as forged and controlled-cooled components. However, use of vanadium microalloyed steels has expanded into applications beyond their originally designed controlled-cooled processing scheme. Applications such as transmission shafts often require additional heat-treatments such as quench and tempering and/or induction hardening to meet packaging or performance requirements. As a result, there is uncertainty regarding the influence of vanadium on the properties of heat-treated components, specifically the effect of rapid heat-treating such as induction hardening. In the current study, the microstructural evolution and torsional fatigue behavior of induction hardened 1045 and 10V45 (0.08 wt pct V) steels were examined. Torsional fatigue specimens specifically designed for this research were machined from the as-received, hot rolled bars and induction hardened using both scanning (96 kHz/72 kW) and single-shot (31 kHz/128 kW) methods. Four conditions were evaluated, three scan hardened to 25, 32, and 44 pct nominal effective case depths and one single-shot hardened to 44 pct. Torsional fatigue tests were conducted at a stress ratio of 0.1 and shear stress amplitudes of 550, 600, and 650 MPa. Physical simulations using the thermal profiles from select induction hardened conditions were conducted in the GleebleRTM 3500 to augment microstructural analysis of torsional fatigue specimens. Thermal profiles were calculated by a collaborating private company using electro-thermal finite element analysis. Residual stresses were evaluated for all conditions using a strain gage hole drilling technique. The results showed that vanadium microalloying has an influence on the microstructure in the highest hardness region of the induction-hardened case as well as the total case region. Vanadium microalloyed conditions consistently exhibited a greater amount of non

Phase Stability and Transformations in Vanadium Oxide Nanocrystals

NASA Astrophysics Data System (ADS)

Bergerud, Amy Jo

Vanadium oxides are both fascinating and complex, due in part to the many compounds and phases that can be stabilized as well as the phase transformations which occur between them. The metal to insulator transitions (MITs) that take place in vanadium oxides are particularly interesting for both fundamental and applied study as they can be induced by a variety of stimuli ( i.e., temperature, pressure, doping) and utilized in many applications (i.e., smart windows, sensors, phase change memory). Nanocrystals also tend to demonstrate interesting phase behavior, due in part to the enhanced influence of surface energy on material thermodynamics. Vanadium oxide nanocrystals are thus expected to demonstrate very interesting properties in regard to phase stability and phase transformations, although synthesizing vanadium oxides in nanocrystal form remains a challenge. Vanadium sesquioxide (V2O3) is an example of a material that undergoes a MIT. For decades, the low temperature monoclinic phase and high temperature corundum phase were the only known crystal structures of V2O3. However, in 2011, a new metastable polymorph of V2O3 was reported with a cubic, bixbyite crystal structure. In Chapter 2, a colloidal route to bixbyite V2O 3 nanocrystals is presented. In addition to being one of the first reported observations of the bixbyite phase in V2O3, it is also one of the first successful colloidal syntheses of any of the vanadium oxides. The nanocrystals possess a flower-like morphology, the size and shape of which are dependent on synthesis time and temperature, respectively. An aminolysis reaction mechanism is determined from Fourier transform infrared spectroscopy data and the bixbyite crystal structure is confirmed by Rietveld refinement of X-ray diffraction (XRD) data. Phase stability is assessed in both air and inert environments, confirming the metastable nature of the material. Upon heating in an inert atmosphere above 700°C, the nanocrystals irreversibly transform

Halofunctionalization of alkenes by vanadium chloroperoxidase from Curvularia inaequalis.

PubMed

Dong, Jia Jia; Fernández-Fueyo, Elena; Li, Jingbo; Guo, Zheng; Renirie, Rokus; Wever, Ron; Hollmann, Frank

2017-06-06

The vanadium-dependent chloroperoxidase from Curvularia inaequalis is a stable and efficient biocatalyst for the hydroxyhalogenation of a broad range of alkenes into halohydrins. Up to 1 200 000 TON with 69 s -1 TOF were observed for the biocatalyst. A bienzymatic cascade to yield epoxides as reaction products is presented.

Vanadium(III)-l-cysteine enhances the sensitivity of murine breast adenocarcinoma cells to cyclophosphamide by promoting apoptosis and blocking angiogenesis.

PubMed

Basu, Abhishek; Bhattacharjee, Arin; Baral, Rathindranath; Biswas, Jaydip; Samanta, Amalesh; Bhattacharya, Sudin

2017-05-01

Various epidemiological and preclinical studies have already established the cancer chemopreventive potential of vanadium-based compounds. In addition to its preventive efficacy, studies have also indicated the abilities of vanadium-based compounds to induce cell death selectively toward malignant cells. Therefore, the objective of the present investigation is to improve the therapeutic efficacy and toxicity profile of an alkylating agent, cyclophosphamide, by the concurrent use of an organovanadium complex, vanadium(III)-l-cysteine. In this study, vanadium(III)-l-cysteine (1 mg/kg body weight, per os) was administered alone as well as in combination with cyclophosphamide (25 mg/kg body weight, intraperitoneal) in concomitant and pretreatment schedule in mice bearing breast adenocarcinoma cells. The results showed that the combination treatment significantly decreased the tumor burden and enhanced survivability of tumor-bearing mice through generation of reactive oxygen species in tumor cells. These ultimately led to DNA damage, depolarization of mitochondrial membrane potential, and apoptosis in tumor cells. Further insight into the molecular pathway disclosed that the combination treatment caused upregulation of p53 and Bax and suppression of Bcl-2 followed by the activation of caspase cascade and poly (ADP-ribose) polymerase cleavage. Administration of vanadium(III)-l-cysteine also resulted in significant attenuation of peritoneal vasculature and sprouting of the blood vessels by decreasing the levels of vascular endothelial growth factor A and matrix metalloproteinase 9 in the ascites fluid of tumor-bearing mice. Furthermore, vanadium(III)-l-cysteine significantly attenuated cyclophosphamide-induced hematopoietic, hepatic, and genetic damages and provided additional survival advantages. Hence, this study suggested that vanadium(III)-l-cysteine may offer potential therapeutic benefit in combination with cyclophosphamide by augmenting anticancer efficacy and

Amorphous and Crystalline Vanadium Oxides as High-Energy and High-Power Cathodes for Three-Dimensional Thin-Film Lithium Ion Batteries.

PubMed

Mattelaer, Felix; Geryl, Kobe; Rampelberg, Geert; Dendooven, Jolien; Detavernier, Christophe

2017-04-19

Flexible wearable electronics and on-chip energy storage for wireless sensors drive rechargeable batteries toward thin-film lithium ion batteries. To enable more charge storage on a given surface, higher energy density materials are required, while faster energy storage and release can be obtained by going to thinner films. Vanadium oxides have been examined as cathodes in classical and thin-film lithium ion batteries for decades, but amorphous vanadium oxide thin films have been mostly discarded. Here, we investigate the use of atomic layer deposition, which enables electrode deposition on complex three-dimensional (3D) battery architectures, to obtain both amorphous and crystalline VO 2 and V 2 O 5 , and we evaluate their thin-film cathode performance. Very high volumetric capacities are found, alongside excellent kinetics and good cycling stability. Better kinetics and higher volumetric capacities were observed for the amorphous vanadium oxides compared to their crystalline counterparts. The conformal deposition of these vanadium oxides on silicon micropillar structures is demonstrated. This study shows the promising potential of these atomic layer deposited vanadium oxides as cathodes for 3D all-solid-state thin-film lithium ion batteries.

Pore-Size-Tuned Graphene Oxide Frameworks as Ion-Selective and Protective Layers on Hydrocarbon Membranes for Vanadium Redox-Flow Batteries.

PubMed

Kim, Soohyun; Choi, Junghoon; Choi, Chanyong; Heo, Jiyun; Kim, Dae Woo; Lee, Jang Yong; Hong, Young Taik; Jung, Hee-Tae; Kim, Hee-Tak

2018-05-07

The laminated structure of graphene oxide (GO) membranes provides exceptional ion-separation properties due to the regular interlayer spacing ( d) between laminate layers. However, a larger effective pore size of the laminate immersed in water (∼11.1 Å) than the hydrated diameter of vanadium ions (>6.0 Å) prevents its use in vanadium redox-flow batteries (VRFB). In this work, we report an ion-selective graphene oxide framework (GOF) with a d tuned by cross-linking the GO nanosheets. Its effective pore size (∼5.9 Å) excludes vanadium ions by size but allows proton conduction. The GOF membrane is employed as a protective layer to address the poor chemical stability of sulfonated poly(arylene ether sulfone) (SPAES) membranes against VO 2 + in VRFB. By effectively blocking vanadium ions, the GOF/SPAES membrane exhibits vanadium-ion permeability 4.2 times lower and a durability 5 times longer than that of the pristine SPAES membrane. Moreover, the VRFB with the GOF/SPAES membrane achieves an energy efficiency of 89% at 80 mA cm -2 and a capacity retention of 88% even after 400 cycles, far exceeding results for Nafion 115 and demonstrating its practical applicability for VRFB.

A new genus of Asterocheridae (Copepoda: Siphonostomatoida) ectoassociate of the ascidian Eudistoma vannamei Millar, 1977 (Polycitoridae) from Brazil.

PubMed

Johnsson, Rodrigo; Bahia, Cristiano; Neves, Elizabeth

2016-05-23

Asterocheres Boeck, 1860 is the largest genus of the siphonostomatoid copepod family Asterocheridae, containing 63 valid species. The genus is known for its symbiotic relationships with many marine invertebrate taxa, especially sponges, cnidarians, bryozoans, and echinoderms. Recent studies have restricted the diagnosis of this genus. Consequently, many species are now considered as species inquirendae. The present paper describes a new species living externally on the tunic of Eudistoma vannamei Millar, 1977, an endemic ascidian from Brazil. As the new species does not fit Asterocheres in the strict sense, a new genus is erected to accommodate it. Setacheres gen. nov. is characterized by its possession of two distal setae on the third endopodal segment of P3, thus differing from the distal seta and spine pattern that is deemed as diagnostic of Asterocheres. A revision and comparison of Asterocheres´ species inquirendae revealed eight species sharing the same generic characteristics and were thus reallocated as members of the new genus.

Blood circulation in the ascidian tunicate Corella inflata (Corellidae)

PubMed Central

2016-01-01

The body of the ascidian tunicate Corella inflata is relatively transparent. Thus, the circulatory system can be visualized by injecting high molecular weight fluorescein labeled dextran into the heart or the large vessels at the ends of the heart without surgery to remove the body wall. In addition, after staining with neutral red, the movement of blood cells can be easily followed to further characterize the circulatory system. The heart is two gently curved concentric tubes extending across the width of the animal. The inner myocardial tube has a partial constriction approximately in the middle. As in other tunicates, the heart is peristaltic and periodically reverses direction. During the branchial phase blood leaves the anterior end of the heart by two asymmetric vessels that connect to the two sides of the branchial basket. Blood then flows in both transverse directions through a complex system of ducts in the basket into large ventral and dorsal vessels which carry blood back to the visceral organs in the posterior of the animal. During the visceral phase blood leaves the posterior end of the heart in two vessels that repeatedly bifurcate and fan into the stomach and gonads. Blood velocity, determined by following individual cells in video frames, is high and pulsatory near the heart. A double peak in velocity at the maximum may be due to the constriction in the middle of the heart tube. Blood velocity progressively decreases with distance from the heart. In peripheral regions with vessels of small diameter blood cells frequently collide with vessel walls and cell motion is erratic. The estimated volume of blood flow during each directional phase is greater than the total volume of the animal. Circulating blood cells are confined to vessels or ducts in the visible parts of the animal and retention of high molecular weight dextran in the vessels is comparable to that seen in vertebrates. These are characteristics of a closed circulatory system. PMID:27994977

IRIS Toxicological Review of Vanadium Pentoxide (Interagency Science Consultation Draft)

EPA Science Inventory

On September 30, 2011, the draft Toxicological Review of Vanadium Pentoxide and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and W...

Vanadium inhibits DNA-protein cross-links and ameliorates surface level changes of aberrant crypt foci during 1,2-dimethylhydrazine induced rat colon carcinogenesis.

PubMed

Kanna, P Suresh; Saralaya, M G; Samanta, K; Chatterjee, M

2005-01-01

The trace mineral vanadium inhibits cancer development in a variety of experimental animal models. The present study was to gain insight into a putative anticancer effect of vanadium in a rat model of colon carcinogenesis. The in vivo study was intended to clarify the effect of vanadium on DNA-protein cross-links (DPC), surface level changes of aberrant crypt foci (ACF) and biotransformation status during 1,2-dimethylhydrazine (1,2-DMH) induced preneoplastic rat colon carcinogenesis. The comet assay showed statistically higher mean base values of DNA-protein mass (p<0.01) and mean frequencies of tailed cells (p<0.001) in the carcinogen-induced group after treatment with proteinase K. Treatment with vanadium in the form of ammonium monovanadate supplemented ad libitum in drinking water for the entire experimental period caused a significant (p<0.02) reduction (40%) in DNA-protein cross-links in colon cells. Further, the biotransformation status of vanadium was ascertained measuring the drug metabolising enzymes, glutathione S-transferase (GST) and cytochrome P-450 (Cyt P-450). Significantly, there was an increase in glutathione S-transferase and cytochrome P-450 levels (p<0.01 and p<0.02, respectively) in rats supplemented with vanadium as compared to their carcinogen controls. As an endpoint marker, we also evaluated the effect of vanadium on surface level changes of aberrant crypt foci induced by 1,2-DMH by scanning electron microscopy. Animals induced with 1,2-DMH and supplemented with vanadium showed a marked improvement in colonic architecture with less number of aberrant crypt foci in contrast to the animals induced with 1,2-DMH alone, thereby exhibiting its anti-carcinogenicity by modulating the markers studied herein.

Friedel–Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery

PubMed Central

Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

2014-01-01

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel–Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion. PMID:24957118

Quantitative Assessment of Proliferative Effects of Oral Vanadium on Pancreatic Islet Volumes and Beta Cell Numbers of Diabetic Rats.

PubMed

Pirmoradi, Leila; Noorafshan, Ali; Safaee, Akbar; Dehghani, Gholam Abbas

2016-01-01

Oral vanadyl sulfate (vanadium) induces normoglycemia, proliferates beta cells and prevents pancreatic islet atrophy in streptozotocin-induced diabetic rats. Soteriological method is used to quantitate the proliferative effects of vanadium on beta-cell numbers and islet volumes of normal and diabetic rats. Adult male Sprague-Dawley rats were made diabetic with intravenous streptozotocin injection (40 mg/kg). Normal and diabetic rats were divided into four groups. While control normal and diabetic (CD) groups used water, vanadium-treated normal (VTN) and diabetic (VTD) groups used solutions containing vanadyl sulfate (0.5-1 mg/mL, VOSO4+5H2O). Tail blood samples were used to measure blood glucose (BG) and plasma insulin. Two months after treatment, rats were sacrificed, pancreata prepared, and stereology method was used to quantitatively evaluate total beta cell numbers (TBCN) and total islet volumes (TISVOL). Normoglycemia persisted in VTN with significantly decreased plasma insulin (0.19±0.08 vs. 0.97±0.27 ng/dL, P<0.002). The respective high BG (532±49 vs. 144±46 mg/dL, P<0.0001) and reduced plasma insulin (0.26±0.15 vs. 0.54±0.19 ng/dL, P<0.002) seen in CD were reversed in VTD during vanadium treatment or withdrawal. While the induction of diabetes, compared to their control, significantly decreased TISVOL (1.9±0.2 vs. 3.03±0.6 mm3, P<0.003) and TBCN (0.99±0.1 vs. 3.2±0.2 x 106, P<0.003), vanadium treatment significantly increased TISVOL (2.9±0.8 and 4.07±1.0 mm3, P<0.003) and TBCN (1.5±0.3 and 3.8±0.6 x 106, P<0.03). Two-month oral vanadium therapy in STZ-diabetic rats ameliorated hyperglycemia by partially restoring plasma insulin. This action was through proliferative actions of vanadium in preventing islet atrophy by increasing beta-cell numbers.

Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

NASA Technical Reports Server (NTRS)

Gray, H. R.

1975-01-01

Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

Capacity Decay Mitigation by Asymmetric Positive/Negative Electrolyte Volumes in Vanadium Redox Flow Batteries.

PubMed

Park, Jong Ho; Park, Jung Jin; Park, O Ok; Yang, Jung Hoon

2016-11-23

Capacity decay in vanadium redox flow batteries during charge-discharge cycling has become an important issue because it lowers the practical energy density of the battery. The battery capacity tends to drop rapidly within the first tens of cycles and then drops more gradually over subsequent cycles during long-term operation. This paper analyzes and discusses the reasons for this early capacity decay. The imbalanced crossover rate of vanadium species was found to remain high until the total difference in vanadium concentration between the positive and negative electrolytes reached almost 1 mol dm -3 . To minimize the initial crossover imbalance, we introduced an asymmetric volume ratio between the positive and negative electrolytes during cell operation. Changing this ratio significantly reduced the capacity fading rate of the battery during the early cycles and improved its capacity retention at steady state. As an example, the practical energy density of the battery increased from 15.5 to 25.2 Wh L -1 simply after reduction of the positive volume by 25 %. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Random quaternary ammonium Diels-Alder poly(phenylene) copolymers for improved vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Largier, Timothy D.; Cornelius, Chris J.

2017-06-01

This study analyzes the effect of quaternary ammonium homopolymer (AmPP) and ionic and non-ionic random unit copolymerization (AmPP-PP) of Diels-Alder poly(phenylene)s on electrochemical and transport properties, vanadium redox flow battery performance, and material stability. AmPP-PP materials were synthesized with IEC's up to 2.2 meq/g, displaying a carbonate form ion conductivity of 17.3 mS/cm and water uptake of 57.3%. Vanadium ion permeability studies revealed that the random copolymers possess superior charge carrier selectivity. For materials of comparable ion content, at 10 mA/cm2 the random copolymer displayed a 14% increase in coulombic efficiency (CE) corresponding to a 7% increase in energy efficiency. All quaternary ammonium materials displayed ex situ degradation in a 0.5 M V5+ + 5 M H2SO4 solution, with the rate of degradation appearing to increase with IEC. Preliminary studies reveal that the neutralizing counter-ion has a significant effect on VRB performance, proportional to changes in vanadium ion molecular diffusion.

Dynamically Switching the Polarization State of Light Based on the Phase Transition of Vanadium Dioxide

NASA Astrophysics Data System (ADS)

Jia, Zhi-Yong; Shu, Fang-Zhou; Gao, Ya-Jun; Cheng, Feng; Peng, Ru-Wen; Fan, Ren-Hao; Liu, Yongmin; Wang, Mu

2018-03-01

There have been great endeavors devoted to manipulating the polarization state of light by plasmonic nanostructures in recent decades. However, the topic of active polarizers has attracted much less attention. We present a composite plasmonic nanostructure consisting of vanadium dioxide that can dynamically modulate the polarization state of the reflected light through a thermally induced phase transition of vanadium dioxide. We design a system consisting of anisotropic plasmonic nanostructures with vanadium dioxide that exhibits distinct reflections subjected to different linearly polarized incidence at room temperature and in the heated state. Under a particular linearly polarized incidence, the polarization state of the reflected light changes at room temperature, and reverts to its original polarization state above the phase-transition temperature. The composite structure can also be used to realize a dynamically switchable infrared image, wherein a pattern can be visualized at room temperature while it disappears above the phase-transition temperature. The composite structure could be potentially used for versatile optical modulators, molecular detection, and polarimetric imaging.

Amorphous vanadium oxide coating on graphene by atomic layer deposition for stable high energy lithium ion anodes.

PubMed

Sun, Xiang; Zhou, Changgong; Xie, Ming; Hu, Tao; Sun, Hongtao; Xin, Guoqing; Wang, Gongkai; George, Steven M; Lian, Jie

2014-09-21

Uniform amorphous vanadium oxide films were coated on graphene via atomic layer deposition and the nano-composite displays an exceptional capacity of ~900 mA h g(-1) at 200 mAg(-1) with an excellent capacity retention at 1 A g(-1) after 200 cycles. The capacity contribution (1161 mA h g(-1)) from vanadium oxide only almost reaches its theoretical value.

Oxidative Stress as a Mechanism Involved in Kidney Damage After Subchronic Exposure to Vanadium Inhalation and Oral Sweetened Beverages in a Mouse Model.

PubMed

Espinosa-Zurutuza, Maribel; González-Villalva, Adriana; Albarrán-Alonso, Juan Carlos; Colín-Barenque, Laura; Bizarro-Nevares, Patricia; Rojas-Lemus, Marcela; López-Valdéz, Nelly; Fortoul, Teresa I

Kidney diseases have notably increased in the last few years. This is partially explained by the increase in metabolic syndrome, diabetes, and systemic blood hypertension. However, there is a segment of the population that has neither of the previous risk factors, yet suffers kidney damage. Exposure to atmospheric pollutants has been suggested as a possible risk factor. Air-suspended particles carry on their surface a variety of fuel combustion-related residues such as metals, and vanadium is one of these. Vanadium might produce oxidative stress resulting in the damage of some organs such as the kidney. Additionally, in countries like Mexico, the ingestion of sweetened beverages is a major issue; whether these beverages alone are responsible for direct kidney damage or whether their ingestion promotes the progression of an existing renal damage generates controversy. In this study, we report the combined effect of vanadium inhalation and sweetened beverages ingestion in a mouse model. Forty CD-1 male mice were distributed in 4 groups: control, vanadium inhalation, 30% sucrose in drinking water, and vanadium inhalation plus sucrose 30% in drinking water. Our results support that vanadium inhalation and the ingestion of 30% sucrose induce functional and histological kidney damage and an increase in oxidative stress biomarkers, which were higher in the combined effect of vanadium plus 30% sucrose. The results also support that the ingestion of 30% sucrose alone without hyperglycemia also produces kidney damage.

Recovery of Vanadium from Magnetite Ore Using Direct Acid Leaching: Optimization of Parameters by Plackett-Burman and Response Surface Methodologies

NASA Astrophysics Data System (ADS)

Nejad, Davood Ghoddocy; Khanchi, Ali Reza; Taghizadeh, Majid

2018-06-01

Recovery of vanadium from magnetite ore by direct acid leaching is discussed. The proposed process, which employs a mixture of nitric and sulfuric acids, avoids pyrometallurgical treatments since such treatment consumes a high amount of energy. To determine the optimum conditions of vanadium recovery, the leaching process is optimized through Plackett-Burman (P-B) design and response surface methodology (RSM). In this respect, temperature (80-95°C), liquid to solid ratio (L/S) (3-10 mL g-1), sulfuric acid concentration (3-6 M), nitric acid concentration (5-10 vol.%) and time (4-8 h) are considered as the independent variables. According to the P-B approach, temperature and acid concentrations are, respectively, the most effective parameters in the leaching process. These parameters are optimized using RSM to maximize recovery of vanadium by direct acid leaching. In this way, 86.7% of vanadium can be extracted from magnetic ore.

Recovery of Vanadium from Magnetite Ore Using Direct Acid Leaching: Optimization of Parameters by Plackett-Burman and Response Surface Methodologies

NASA Astrophysics Data System (ADS)

Nejad, Davood Ghoddocy; Khanchi, Ali Reza; Taghizadeh, Majid

2018-03-01

Recovery of vanadium from magnetite ore by direct acid leaching is discussed. The proposed process, which employs a mixture of nitric and sulfuric acids, avoids pyrometallurgical treatments since such treatment consumes a high amount of energy. To determine the optimum conditions of vanadium recovery, the leaching process is optimized through Plackett-Burman (P-B) design and response surface methodology (RSM). In this respect, temperature (80-95°C), liquid to solid ratio (L/S) (3-10 mL g-1), sulfuric acid concentration (3-6 M), nitric acid concentration (5-10 vol.%) and time (4-8 h) are considered as the independent variables. According to the P-B approach, temperature and acid concentrations are, respectively, the most effective parameters in the leaching process. These parameters are optimized using RSM to maximize recovery of vanadium by direct acid leaching. In this way, 86.7% of vanadium can be extracted from magnetic ore.

Vanadium-Catalyzed C(sp3)–H Fluorination Reactions†

PubMed Central

Xia, Ji-Bao; Ma, Yuyong; Chen, Chuo

2014-01-01

Vanadium(III) oxide catalyzes the direct fluorination of C(sp3)–H groups with Selectfluor. This reaction is operationally simple. The catalyst and the reaction byproduct can be removed easily by filtration. Using this method, a fluorine atom can be introduced to the tertiary position of 1,4-cineole and L-menthone selectively. PMID:24976971

Protective effect of alpha glucosyl hesperidin (G-hesperidin) on chronic vanadium induced testicular toxicity and sperm nuclear DNA damage in male Sprague Dawley rats.

PubMed

Vijaya Bharathi, B; Jaya Prakash, G; Krishna, K M; Ravi Krishna, C H; Sivanarayana, T; Madan, K; Rama Raju, G A; Annapurna, A

2015-06-01

The study was conducted to evaluate the vanadium-induced testicular toxicity and its effect on sperm parameters, sperm nuclear DNA damage and histological alterations in Sprague Dawley rats and to assess the protective effect of G-hesperidin against this damage. Treatment of rats with vanadium at a dose of 1 mg kg bw(-1) for 90 days resulted in significant reduction in serum testosterone levels, sperm count and motility. Further, a parallel increase in abnormal sperm morphology and adverse histopathological changes in testis was also associated with vanadium administration when compared to normal control. Moreover, sperm chromatin dispersion assay revealed that vanadium induces sperm nuclear DNA fragmentation. A marked increase in testicular malondialdehyde levels and decreased activity of antioxidant enzymes such as superoxide dismutase and catalase indicates vanadium-induced oxidative stress. Co-administration of G-hesperidin at a dose of 25 and 50 mg kg bw(-1) significantly attenuated the sperm parameters and histological changes by restoring the antioxidant levels in rat testis. These results suggested that vanadium exposure caused reduced bioavailability of androgens to the tissue and increased free radical formation, thereby causing structural and functional changes in spermatozoa. G-hesperidin exhibited antioxidant effect by protecting the rat testis against vanadium-induced oxidative damage, further ensures antioxidant potential of bioflavonoids. © 2014 Blackwell Verlag GmbH.

Thermodynamic derivation of open circuit voltage in vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Pavelka, Michal; Wandschneider, Frank; Mazur, Petr

2015-10-01

Open circuit voltage of vanadium redox flow batteries is carefully calculated using equilibrium thermodynamics. This analysis reveals some terms in the Nernst relation which are usually omitted in literature. Due to the careful thermodynamic treatment, all uncertainties about the form of Nernst relation are removed except for uncertainties in activity coefficients of particular species. Moreover, it is shown (based again on equilibrium thermodynamics) that batteries with anion-exchange membranes follow different Nernst relation than batteries with cation-exchange membranes. The difference is calculated, and it is verified experimentally that the formula for anion-exchange membranes describes experiments with anion-exchange membranes better than the corresponding formula for cation-exchange membranes. In summary, careful thermodynamic calculation of open circuit voltage of vanadium redox flow batteries is presented, and the difference between voltage for anion-exchange and cation-exchange membranes is revealed.

Synthesis and luminescence properties of vanadium-doped nanosized zinc oxide aerogel

NASA Astrophysics Data System (ADS)

El Mir, L.; El Ghoul, J.; Alaya, S.; Ben Salem, M.; Barthou, C.; von Bardeleben, H. J.

2008-05-01

We report the elaboration of vanadium-doped ZnO nanoparticles prepared by a sol-gel processing technique. In our approach, the water for hydrolysis was slowly released by esterification reaction followed by a supercritical drying in ethyl alcohol. Vanadium doping concentration of 10 at% has been investigated. The obtained nanopowder was characterised by various techniques such as particle size analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence (PL). In the as-prepared state, the powder with an average particle size of 25 nm presents a strong luminescence band in the visible range after thermal treatment at 500 °C in air. The energy position of the obtained PL band depends on the wavelength excitation and presents a blue shift with measurement temperature increase. Different possible attributions of this emission band will be discussed.

Reductive transformation of V(iii) precursors into vanadium(ii) oxide nanowires.

PubMed

Ojelere, Olusola; Graf, David; Ludwig, Tim; Vogt, Nicholas; Klein, Axel; Mathur, Sanjay

2018-05-15

Vanadium(ii) oxide nanostructures are promising materials for supercapacitors and electrocatalysis because of their excellent electrochemical properties and high surface area. In this study, new homoleptic vanadium(iii) complexes with bi-dentate O,N-chelating heteroarylalkenol ligands (DmoxCH[double bond, length as m-dash]COCF3, PyCH[double bond, length as m-dash]COCF3 and PyN[double bond, length as m-dash]COCF3) were synthesized and successfully transformed by reductive conversion into VO nanowires. The chemical identity of V(iii) complexes and their redox behaviour were unambiguously established by single crystal X-ray diffraction studies, cyclic voltammetry, spectrometric studies and DFT calculations. Transformation into the metastable VO phase was verified by powder X-ray diffraction and thermo-gravimetry. Transmission electron microscopy and X-ray photoelectron spectroscopy data confirmed the morphology and chemical composition of VO nanostructures, respectively.

Study on the poisoning effect-of non-vanadium catalysts by potassium

NASA Astrophysics Data System (ADS)

Zeng, Huanmu; Liu, Ying; Yu, Xiaowei; Lin, Yasi

2018-02-01

The poisoning effect of catalyst by alkali metals is one of the problems in the selective catalytic reduction (SCR) of NO by NH3. Serious deactivation by alkali poisoning have been proved to take place in the commercial vanadium catalyst. Recently, non-vanadium catalysts such as copper oxides, manganese oxides, chromium oxides and cerium oxides have attracted special attentions in SCR application. However, their tolerance in the presence of alkali metals is still doubtful. In this paper, copper oxides, manganese oxides, chromium oxides and cerium oxides supported on TiO2 nanoparticle was prepared by impregnating method. Potassium nitrate was chosen as the precursor of poisoner. Catalytic activities of these catalysts were evaluated before and after the addition of potassium. Some characterization methods including X-ray diffraction and temperature programmed desorption was utilized to reveal the main reason of alkali deactivation.

Roll-to-Roll Processing of Inverted Polymer Solar Cells using Hydrated Vanadium(V)Oxide as a PEDOT:PSS Replacement.

PubMed

Espinosa, Nieves; Dam, Henrik Friis; Tanenbaum, David M; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

2011-01-11

The use of hydrated vanadium(V)oxide as a replacement of the commonly employed hole transporting material PEDOT:PSS was explored in this work. Polymer solar cells were prepared by spin coating on glass. Polymer solar cells and modules comprising 16 serially connected cells were prepared using full roll-to-roll (R2R) processing of all layers. The devices were prepared on flexible polyethyleneterphthalate (PET) and had the structure PET/ITO/ZnO/P3HT:PCBM/V₂O₅·(H₂O) n /Ag. The ITO and silver electrodes were processed and patterned by use of screen printing. The zinc oxide, P3HT:PCBM and vanadium(V)oxide layers were processed by slot-die coating. The hydrated vanadium(V)oxide layer was slot-die coated using an isopropanol solution of vanadyl-triisopropoxide (VTIP). Coating experiments were carried out to establish the critical thickness of the hydrated vanadium(V)oxide layer by varying the concentration of the VTIP precursor over two orders of magnitude. Hydrated vanadium(V)oxide layers were characterized by profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and grazing incidence wide angle X-ray scattering. The power conversion efficiency (PCE) for completed modules was up to 0.18%, in contrast to single cells where efficiencies of 0.4% were achieved. Stability tests under indoor and outdoor conditions were accomplished over three weeks on a solar tracker.

Insulin-like genes in ascidians: findings in Ciona and hypotheses on the evolutionary origins of the pancreas