Determination of the oxidation states of metals and metalloids: An analytical review

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.

2013-12-01

The hazard of many heavy metals/metalloids in the soil depends on their oxidation state. The problem of determining the oxidation state has been solved due to the use of synchrotron radiation methods with the analysis of the X-ray absorption near-edge structure (XANES). The determination of the oxidation state is of special importance for some hazardous heavy elements (arsenic, antimony, selenium, chromium, uranium, and vanadium). The mobility and hazard of each of these elements depend on its oxidation state. The mobilities are higher at lower oxidation states of As, Cr, V, and Se and at higher oxidation states of Sb and U. The determination of the oxidation state of arsenic has allowed revealing its fixation features in the rhizosphere of hydrophytes. The known oxidation states of chromium and uranium are used for the retention of these elements on geochemical barriers. Different oxidation states have been established for vanadium displacing iron in goethite. The determination of the oxidation state of manganese in the rhizosphere and the photosynthetic apparatus of plants is of special importance for agricultural chemists.

Residential Broadband Access for Students at Walters State Community College

ERIC Educational Resources Information Center

Hurst, Mark A.

2010-01-01

The purpose of this study was to determine the availability of internet access for students attending Walters State Community College during the spring semester 2010. In particular, it is unknown to what degree broadband internet access is available in the counties that Walters State considers the service area of the college. The research was…

Energy Access Solutions Advance Gender Mainstreaming in West African States

Science.gov Websites

| Integrated Energy Solutions | NREL Energy Access Solutions Advance Gender Mainstreaming in West African States Energy Access Solutions Advance Gender Mainstreaming in West African States Under a expertise to an innovative policy that not only supports women in energy, but also helps bring clean energy

Tutorial on the Role of Cyclopentadienyl Ligands in the Discovery of Molecular Complexes of the Rare-Earth and Actinide Metals in New Oxidation States

DOE PAGES

Evans, William J.

2016-09-15

A fundamental aspect of any element is the range of oxidation states accessible for useful chemistry. This tutorial describes the recent expansion of the number of oxidation states available to the rare-earth and actinide metals in molecular complexes that has resulted through organometallic chemistry involving the cyclopentadienyl ligand. These discoveries demonstrate that the cyclopentadienyl ligand, which has been a key component in the development of organometallic chemistry since the seminal discovery of ferrocene in the 1950s, continues to contribute to the advancement of science. Lastly, we present background information on the rare-earth and actinide elements, as well as the sequencemore » of events that led to these unexpected developments in the oxidation state chemistry of these metals.« less

Tutorial on the Role of Cyclopentadienyl Ligands in the Discovery of Molecular Complexes of the Rare-Earth and Actinide Metals in New Oxidation States

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

Evans, William J.

A fundamental aspect of any element is the range of oxidation states accessible for useful chemistry. This tutorial describes the recent expansion of the number of oxidation states available to the rare-earth and actinide metals in molecular complexes that has resulted through organometallic chemistry involving the cyclopentadienyl ligand. These discoveries demonstrate that the cyclopentadienyl ligand, which has been a key component in the development of organometallic chemistry since the seminal discovery of ferrocene in the 1950s, continues to contribute to the advancement of science. Lastly, we present background information on the rare-earth and actinide elements, as well as the sequencemore » of events that led to these unexpected developments in the oxidation state chemistry of these metals.« less

Implementing the Equal Access Act and State Constitutional Provisions.

ERIC Educational Resources Information Center

Bjorklun, Eugene C.

1992-01-01

Examines the issue of whether implementation of the Equal Access Act would violate the constitutions of some states that require a stricter separation of church and state than the federal Constitution. (MLF)

Atomic Layer Deposited Oxide-Based Nanocomposite Structures with Embedded CoPtx Nanocrystals for Resistive Random Access Memory Applications.

PubMed

Wang, Lai-Guo; Cao, Zheng-Yi; Qian, Xu; Zhu, Lin; Cui, Da-Peng; Li, Ai-Dong; Wu, Di

2017-02-22

Al 2 O 3 - or HfO 2 -based nanocomposite structures with embedded CoPt x nanocrystals (NCs) on TiN-coated Si substrates have been prepared by combination of thermal atomic layer deposition (ALD) and plasma-enhanced ALD for resistive random access memory (RRAM) applications. The impact of CoPt x NCs and their average size/density on the resistive switching properties has been explored. Compared to the control sample without CoPt x NCs, ALD-derived Pt/oxide/100 cycle-CoPt x NCs/TiN/SiO 2 /Si exhibits a typical bipolar, reliable, and reproducible resistive switching behavior, such as sharp distribution of RRAM parameters, smaller set/reset voltages, stable resistance ratio (≥10 2 ) of OFF/ON states, better switching endurance up to 10 4 cycles, and longer data retention over 10 5 s. The possible resistive switching mechanism based on nanocomposite structures of oxide/CoPt x NCs has been proposed. The dominant conduction mechanisms in low- and high-resistance states of oxide-based device units with embedded CoPt x NCs are Ohmic behavior and space-charge-limited current, respectively. The insertion of CoPt x NCs can effectively improve the formation of conducting filaments due to the CoPt x NC-enhanced electric field intensity. Besides excellent resistive switching performances, the nanocomposite structures also simultaneously present ferromagnetic property. This work provides a flexible pathway by combining PEALD and TALD compatible with state-of-the-art Si-based technology for multifunctional electronic devices applications containing RRAM.

Geographic access to high capability severe acute respiratory failure centers in the United States.

PubMed

Wallace, David J; Angus, Derek C; Seymour, Christopher W; Yealy, Donald M; Carr, Brendan G; Kurland, Kristen; Boujoukos, Arthur; Kahn, Jeremy M

2014-01-01

Optimal care of adults with severe acute respiratory failure requires specific resources and expertise. We sought to measure geographic access to these centers in the United States. Cross-sectional analysis of geographic access to high capability severe acute respiratory failure centers in the United States. We defined high capability centers using two criteria: (1) provision of adult extracorporeal membrane oxygenation (ECMO), based on either 2008-2013 Extracorporeal Life Support Organization reporting or provision of ECMO to 2010 Medicare beneficiaries; or (2) high annual hospital mechanical ventilation volume, based 2010 Medicare claims. Nonfederal acute care hospitals in the United States. We defined geographic access as the percentage of the state, region and national population with either direct or hospital-transferred access within one or two hours by air or ground transport. Of 4,822 acute care hospitals, 148 hospitals met our ECMO criteria and 447 hospitals met our mechanical ventilation criteria. Geographic access varied substantially across states and regions in the United States, depending on center criteria. Without interhospital transfer, an estimated 58.5% of the national adult population had geographic access to hospitals performing ECMO and 79.0% had geographic access to hospitals performing a high annual volume of mechanical ventilation. With interhospital transfer and under ideal circumstances, an estimated 96.4% of the national adult population had geographic access to hospitals performing ECMO and 98.6% had geographic access to hospitals performing a high annual volume of mechanical ventilation. However, this degree of geographic access required substantial interhospital transfer of patients, including up to two hours by air. Geographic access to high capability severe acute respiratory failure centers varies widely across states and regions in the United States. Adequate referral center access in the case of disasters and pandemics will

Higher Americium Oxidation State Research Roadmap

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

Mincher, Bruce J.; Law, Jack D.; Goff, George S.

2015-12-18

The partitioning of hexavalent Am from dissolved nuclear fuel requires the ability to efficiently oxidize Am(III) to Am(VI) and to maintain that oxidation state for a length of time sufficient to perform the separation. Several oxidants have been, or are being developed. Chemical oxidants include Ag-catalyzed ozone, Ag-catalyzed peroxydisulfate, Cu(III) periodate, and sodium bismuthate. Hexavalent americium has also now successfully been prepared by electrolysis, using functionalized electrodes. So-called auto-reduction rates of Am(VI) are sufficiently slow to allow for separations. However, for separations based on solvent extraction or ion exchange using organic resins, the high valence state must be maintained undermore » the reducing conditions of the organic phase contact, and a holding oxidant is probably necessary. Until now, only Cu(III) periodate and sodium bismuthate oxidation have been successfully combined with solvent extraction separations. Bismuthate oxidation provided the higher DAm, since it acts as its own holding oxidant, and a successful hot test using centrifugal contactors was performed. For the other oxidants, Ag-catalyzed peroxydisulfate will not oxidize americium in nitric acid concentrations above 0.3 M, and it is not being further investigated. Peroxydisulfate in the absence of Ag catalysis is being used to prepare Am(V) in ion exchange work, discussed below. Preliminary work with Ag-catalyzed ozone has been unsuccessful for extractions of Am(VI) from 6.5 M HNO3, and only one attempt at extraction, also from 6.5 M HNO3, using the electrolytic oxidation has been attempted. However, this high acid concentration was based on the highest Am extraction efficiency using the bismuthate oxidant; which is only sparingly soluble, and thus the oxidation yield is based on bismuthate solubility. Lower acid concentrations may be sufficient with alternative oxidants and work with Ag-ozone, Cu(III) and electrolysis is on-going. Two non

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors

NASA Astrophysics Data System (ADS)

Yang, Jyun-Bao; Chang, Ting-Chang; Huang, Jheng-Jie; Chen, Yu-Chun; Chen, Yu-Ting; Tseng, Hsueh-Chih; Chu, Ann-Kuo; Sze, Simon M.

2014-04-01

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

Using X-ray absorption to probe sulfur oxidation states in complex molecules

NASA Astrophysics Data System (ADS)

Vairavamurthy, A.

1998-10-01

X-ray absorption near-edge structure (XANES) spectroscopy offers an important non-destructive tool for determining oxidation states and for characterizing chemical speciation. The technique was used to experimentally verify the oxidation states of sulfur in different types of complex molecules because there are irregularities and uncertainties in assigning the values traditionally. The usual practice of determining oxidation states involves using a set of conventional rules. The oxidation state is an important control in the chemical speciation of sulfur, ranging from -2 to +6 in its different compounds. Experimental oxidation-state values for various types of sulfur compounds, using their XANES peak-energy positions, were assigned from a scale in which elemental sulfur and sulfate are designated as 0 and +6, respectively. Because these XANES-based values differed considerably from conventionally determined oxidation states for most sulfur compounds, a new term 'oxidation index' was coined to describe them. The experimental values were closer to those conventional values obtained by assigning shared electrons to the more electronegative atoms than to those based on other customary rules for assigning them. Because the oxidation index is distinct and characteristic for each different type of sulfur functionality, it becomes an important parameter for characterizing sulfur species, and for experimentally verifying uncertain oxidation states.

Current state of web accessibility of Malaysian ministries websites

NASA Astrophysics Data System (ADS)

Ahmi, Aidi; Mohamad, Rosli

2016-08-01

Despite the fact that Malaysian public institutions have progressed considerably on website and portal usage, web accessibility has been reported as one of the issues deserves special attention. Consistent with the government moves to promote an effective use of web and portal, it is essential for the government institutions to ensure compliance with established standards and guidelines on web accessibility. This paper evaluates accessibility of 25 Malaysian ministries websites using automated tools i.e. WAVE and Achecker. Both tools are designed to objectively evaluate web accessibility in conformance with Web Content Accessibility Guidelines 2.0 (WCAG 2.0) and United States Rehabilitation Act 1973 (Section 508). The findings reported somewhat low compliance to web accessibility standard amongst the ministries. Further enhancement is needed in the aspect of input elements such as label and checkbox to be associated with text as well as image-related elements. This findings could be used as a mechanism for webmasters to locate and rectify errors pertaining to the web accessibility and to ensure equal access of the web information and services to all citizen.

Average oxidation state of carbon in proteins

PubMed Central

Dick, Jeffrey M.

2014-01-01

The formal oxidation state of carbon atoms in organic molecules depends on the covalent structure. In proteins, the average oxidation state of carbon (ZC) can be calculated as an elemental ratio from the chemical formula. To investigate oxidation–reduction (redox) patterns, groups of proteins from different subcellular locations and phylogenetic groups were selected for comparison. Extracellular proteins of yeast have a relatively high oxidation state of carbon, corresponding with oxidizing conditions outside of the cell. However, an inverse relationship between ZC and redox potential occurs between the endoplasmic reticulum and cytoplasm. This trend provides support for the hypothesis that protein transport and turnover are ultimately coupled to the maintenance of different glutathione redox potentials in subcellular compartments. There are broad changes in ZC in whole-genome protein compositions in microbes from different environments, and in Rubisco homologues, lower ZC tends to occur in organisms with higher optimal growth temperature. Energetic costs calculated from thermodynamic models are consistent with the notion that thermophilic organisms exhibit molecular adaptation to not only high temperature but also the reducing nature of many hydrothermal fluids. Further characterization of the material requirements of protein metabolism in terms of the chemical conditions of cells and environments may help to reveal other linkages among biochemical processes with implications for changes on evolutionary time scales. PMID:25165594

Direct Determination of the Intracellular Oxidation State of Plutonium

PubMed Central

Gorman-Lewis, Drew; Aryal, Baikuntha P.; Paunesku, Tatjana; Vogt, Stefan; Lai, Barry; Woloschak, Gayle E.; Jensen, Mark P.

2013-01-01

Microprobe X-ray absorption near edge structure (μ-XANES) measurements were used to determine directly, for the first time, the oxidation state of intracellular plutonium in individual 0.1 μm2 areas within single rat pheochromocytoma cells (PC12). The living cells were incubated in vitro for 3 hours in the presence of Pu added to the media in different oxidation states (Pu(III), Pu(IV), and Pu(VI)) and in different chemical forms. Regardless of the initial oxidation state or chemical form of Pu presented to the cells, the XANES spectra of the intracellular Pu deposits was always consistent with tetravalent Pu even though the intracellular milieu is generally reducing. PMID:21755934

Spin State Control of the Perovskite Rh/Co Oxides

PubMed Central

Terasaki, Ichiro; Shibasaki, Soichiro; Yoshida, Shin; Kobayashi, Wataru

2010-01-01

We show why and how the spin state of transition-metal ions affects the thermoelectric properties of transition-metal oxides by investigating two perovskite-related oxides. In the A-site ordered cobalt oxide Sr3YCo4O10.5, partial substitution of Ca for Sr acts as chemical pressure, which compresses the unit cell volume to drive the spin state crossover, and concomitantly changes the magnetization and thermopower. In the perovskite rhodium oxide LaRhO3, partial substitution of Sr for La acts as hole-doping, and the resistivity and thermopower decrease systematically with the Sr concentration. The thermopower remains large values at high temperatures (>150 μV/K at 800 K), which makes a remarkable contrast to La1−xSrxCoO3. We associate this with the stability of the low spin state of the Rh3+ ions.

Access Guide to South Carolina State Parks for People with Special Needs.

ERIC Educational Resources Information Center

South Carolina State Dept. of Parks, Recreation, and Tourism, Columbia. Div. of Engineering and Planning.

The guide was developed to assist physically handicapped persons in using South Carolina State Parks. It describes some of the accessibility problems identified in a 1986 Inventory of Handicapped Accessibility in South Carolina State Parks and Welcome Centers. It is noted that building construction since 1967 has met handicapped design criteria…

Oxidation State of Nakhlites as inferred from Fe-Ti oxide Equilibria and Augite/Melt Europium Partitioning

NASA Technical Reports Server (NTRS)

Makishima, J.; McKay, G.; Le, L.; Miyamoto, M.; Mikouchi, T.

2007-01-01

Recent studies have shown that Martian magmas had wide range of oxygen fugacities (fO2) and that this variation is correlated with the variation of La/Yb ratio and isotopic characteristics of the Martian basalts, shergottite meteorites. The origin of this correlation must have important information about mantle sources and Martian evolution. In order to understand this correlation, it is necessary to know accurate value of oxidation state of other Martian meteorite groups. Nakhlites, cumulate clinopyroxenites, are another major group of Martian meteorites and have distinctly different trace element and isotopic characteristics from shergottites. Thus, estimates of oxidation state of nakhlites will give us important insight into the mantle source in general. Several workers have estimated oxidation state of nakhlites by using Fe-Ti oxide equilibrium. However, Fe-Ti oxides may not record the oxidation state of the parent melt of the nakhlite because it is a late-stage mineral. Furthermore, there is no comprehensive study which analyzed all nakhlite samples at the same time. Therefore, in this study (1) we reduced the uncertainty of the estimate using the same electron microprobe and the same standards under the same condition for Fe-Ti oxide in 6 nakhlites and (2) we also performed crystallization experiments to measure partition coefficients of Eu into pyroxene in the nakhlite system in order to estimate fO2 when the pyroxene core formed (i.e. Eu oxybarometer [e.g. 2,6]).

State K-12 Broadband Leadership: Driving Connectivity and Access

ERIC Educational Resources Information Center

Fox, Christine; Jones, Rachel

2016-01-01

In this report, State Educational Technology Directors Association (SETDA) builds upon the research and recommendations from prior publications with a focus on the role of state leadership in supporting districts and schools to increase high-speed connectivity and access for students and educators. SETDA firmly believes that high-speed broadband…

State Medicaid Coverage for Tobacco Cessation Treatments and Barriers to Accessing Treatments - United States, 2015-2017.

PubMed

DiGiulio, Anne; Jump, Zach; Yu, Annie; Babb, Stephen; Schecter, Anna; Williams, Kisha-Ann S; Yembra, Debbie; Armour, Brian S

2018-04-06

Cigarette smoking prevalence among Medicaid enrollees (25.3%) is approximately twice that of privately insured Americans (11.8%), placing Medicaid enrollees at increased risk for smoking-related disease and death (1). Medicaid spends approximately $39 billion annually on treating smoking-related diseases (2). Individual, group, and telephone counseling and seven Food and Drug Administration (FDA)-approved medications* are effective in helping tobacco users quit (3). Although state Medicaid coverage of tobacco cessation treatments improved during 2014-2015, coverage was still limited in most states (4). To monitor recent changes in state Medicaid cessation coverage for traditional (i.e., nonexpansion) Medicaid enrollees, the American Lung Association collected data on coverage of a total of nine cessation treatments: individual counseling, group counseling, and seven FDA-approved cessation medications † in state Medicaid programs during July 1, 2015-June 30, 2017. The American Lung Association also collected data on seven barriers to accessing covered treatments, such as copayments and prior authorization. As of June 30, 2017, 10 states covered all nine of these treatments for all enrollees, up from nine states as of June 30, 2015; of these 10 states, Missouri was the only state to have removed all seven barriers to accessing these cessation treatments. State Medicaid programs that cover all evidence-based cessation treatments, remove barriers to accessing these treatments, and promote covered treatments to Medicaid enrollees and health care providers would be expected to reduce smoking, smoking-related disease, and smoking-attributable federal and state health care expenditures (5-7).

Improved characteristics of amorphous indium-gallium-zinc-oxide-based resistive random access memory using hydrogen post-annealing

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

Kang, Dae Yun; Lee, Tae-Ho; Kim, Tae Geun, E-mail: tgkim1@korea.ac.kr

The authors report an improvement in resistive switching (RS) characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO)-based resistive random access memory devices using hydrogen post-annealing. Because this a-IGZO thin film has oxygen off-stoichiometry in the form of deficient and excessive oxygen sites, the film properties can be improved by introducing hydrogen atoms through the annealing process. After hydrogen post-annealing, the device exhibited a stable bipolar RS, low-voltage set and reset operation, long retention (>10{sup 5 }s), good endurance (>10{sup 6} cycles), and a narrow distribution in each current state. The effect of hydrogen post-annealing is also investigated by analyzing the sample surface using X-raymore » photon spectroscopy and atomic force microscopy.« less

Oxidation state of marine manganese nodules

USGS Publications Warehouse

Piper, D.Z.; Basler, J.R.; Bischoff, J.L.

1984-01-01

Analyses of the bulk oxidation state of marine manganese nodules indicates that more than 98% of the Mn in deep ocean nodules is present as Mn(IV). The samples were collected from three quite different areas: the hemipelagic environment of the Guatemala Basin, the pelagic area of the North Pacific, and seamounts in the central Pacific. Results of the study suggest that todorokite in marine nodules is fully oxidized and has the following stoichiometry: (K, Na, Ca, Ba).33(Mg, Cu, Ni).76Mn5O22(H2O)3.2. ?? 1984.

Covalency in oxidized uranium

NASA Astrophysics Data System (ADS)

Tobin, J. G.; Yu, S.-W.; Qiao, R.; Yang, W. L.; Booth, C. H.; Shuh, D. K.; Duffin, A. M.; Sokaras, D.; Nordlund, D.; Weng, T.-C.

2015-07-01

Using x-ray emission spectroscopy and absorption spectroscopy, it has been possible to directly access the states in the unoccupied conduction bands that are involved with 5 f and 6 d covalency in oxidized uranium. By varying the oxidizing agent, the degree of 5 f covalency can be manipulated and monitored, clearly and irrevocably establishing the importance of 5 f covalency in the electronic structure of the key nuclear fuel, uranium dioxide.

Covalency in oxidized uranium

DOE PAGES

Tobin, J. G.; Yu, S. -W.; Qiao, R.; ...

2015-07-01

Here, using x-ray emission spectroscopy and absorption spectroscopy, it has been possible to directly access the states in the unoccupied conduction bands that are involved with 5f and 6d covalency in oxidized uranium. By varying the oxidizing agent, the degree of 5f covalency can be manipulated and monitored, clearly and irrevocably establishing the importance of 5f covalency in the electronic structure of the key nuclear fuel, uranium dioxide.

Tri-state resistive switching characteristics of MnO/Ta2O5 resistive random access memory device by a controllable reset process

NASA Astrophysics Data System (ADS)

Lee, N. J.; Kang, T. S.; Hu, Q.; Lee, T. S.; Yoon, T.-S.; Lee, H. H.; Yoo, E. J.; Choi, Y. J.; Kang, C. J.

2018-06-01

Tri-state resistive switching characteristics of bilayer resistive random access memory devices based on manganese oxide (MnO)/tantalum oxide (Ta2O5) have been studied. The current–voltage (I–V) characteristics of the Ag/MnO/Ta2O5/Pt device show tri-state resistive switching (RS) behavior with a high resistance state (HRS), intermediate resistance state (IRS), and low resistance state (LRS), which are controlled by the reset process. The MnO/Ta2O5 film shows bipolar RS behavior through the formation and rupture of conducting filaments without the forming process. The device shows reproducible and stable RS both from the HRS to the LRS and from the IRS to the LRS. In order to elucidate the tri-state RS mechanism in the Ag/MnO/Ta2O5/Pt device, transmission electron microscope (TEM) images are measured in the LRS, IRS and HRS. White lines like dendrites are observed in the Ta2O5 film in both the LRS and the IRS. Poole–Frenkel conduction, space charge limited conduction, and Ohmic conduction are proposed as the dominant conduction mechanisms for the Ag/MnO/Ta2O5/Pt device based on the obtained I–V characteristics and TEM images.

Shifts in oxidation states of cerium oxide nanoparticles detected inside intact hydrated cells and organelles

PubMed Central

Szymanski, Craig J.; Munusamy, Prabhakaran; Mihai, Cosmin; Xie, Yumei; Hu, Dehong; Gilles, Mary K.; Tyliszczak, Tolek; Thevuthasan, Suntharampillai; Baer, Donald R.; Orr, Galya

2015-01-01

Cerium oxide nanoparticles (CNPs) have been shown to induce diverse biological effects, ranging from toxic to beneficial. The beneficial effects have been attributed to the potential antioxidant activity of CNPs via certain redox reactions, depending on their oxidation state or Ce3+/Ce4+ ratio. However, this ratio is strongly dependent on the environment and age of the nanoparticles and it is unclear whether and how the complex intracellular environment impacts this ratio and the possible redox reactions of CNPs. To identify any changes in the oxidation state of CNPs in the intracellular environment and better understand their intracellular reactions, we directly quantified the oxidation states of CNPs outside and inside intact hydrated cells and organelles using correlated scanning transmission x-ray and super resolution fluorescence microscopies. By analyzing hundreds of small CNP aggregates, we detected a shift to a higher Ce3+/Ce4+ ratio in CNPs inside versus outside the cells, indicating a net reduction of CNPs in the intracellular environment. We further found a similar ratio in the cytoplasm and in the lysosomes, indicating that the net reduction occurs earlier in the internalization pathway. Together with oxidative stress and toxicity measurements, our observations identify a net reduction of CNPs in the intracellular environment, which is consistent with their involvement in potentially beneficial oxidation reactions, but also point to interactions that can negatively impact the health of cells. PMID:26056725

Shifts in oxidation states of cerium oxide nanoparticles detected inside intact hydrated cells and organelles

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

Szymanski, Craig J.; Munusamy, Prabhakaran; Mihai, Cosmin

2015-09-01

Cerium oxide nanoparticles (CNPs) have been shown to induce diverse biological effects, ranging from toxic to beneficial. The beneficial effects have been attributed to the potential antioxidant activity of CNPs via certain redox reactions, depending on their oxidation state or Ce3+/Ce4+ ratio. However, this ratio is strongly dependent on the environment and age of the nanoparticles and it is unclear whether and how the complex intracellular environment impacts this ratio and the possible redox reactions of CNPs. To identify any changes in the oxidation state of CNPs in the intracellular environment and better understand their intracellular reactions, we directly quantifiedmore » the oxidation states of CNPs outside and inside intact hydrated cells and organelles using correlated scanning transmission x-ray and super resolution fluorescence microscopies. By analyzing hundreds of small CNP aggregates, we detected a shift to a higher Ce3+/Ce4+ ratio in CNPs inside versus outside the cells, indicating a net reduction of CNPs in the intracellular environment. We further found a similar ratio in the cytoplasm and in the lysosomes, indicating that the net reduction occurs earlier in the internalization pathway. Together with oxidative stress and toxicity measurements, our observations identify a net reduction of CNPs in the intracellular environment, which is consistent with their involvement in potentially beneficial oxidation reactions, but also point to interactions that can negatively impact the health of cells.« less

Expanding oral care opportunities: direct access care provided by dental hygienists in the United States.

PubMed

Naughton, Doreen K

2014-06-01

Dental hygienists expand access to oral care in the United States. Many Americans have access to oral health care in traditional dental offices however millions of Americans have unmet dental needs. For decades dental hygienists have provided opportunities for un-served and under-served Americans to receive preventive services in a variety of alternate delivery sites, and referral to licensed dentists for dental care needs. Publications, state practice acts, state public health departments, the American Dental Hygienists' Association, and personal interviews of dental hygiene practitioners were accessed for information and statistical data. Dental hygienists in 36 states can legally provide direct access care. Dental hygienists are providing preventive services in a variety of settings to previously un-served and under-served Americans, with referral to dentists for dental needs. Dental hygienists have provided direct access to care in the United States for decades. The exact number of direct access providers in the United States is unknown. Limited research and anecdotal information demonstrate that direct access care has facilitated alternate entry points into the oral health systems for thousands of previously un-served and underserved Americans. Older adults, persons with special needs, children in schools, pregnant women, minority populations, rural populations, and others have benefited from the availability of many services provided by direct access dental hygienists. Legislatures and private groups are becoming increasingly aware of the impact that direct access has made on the delivery of oral health care. Many factors continue to drive the growth of direct access care. Additional research is needed to accumulate qualitative and quantitative outcome data related to direct access care provided by dental hygienists and other mid level providers of oral health services. Copyright © 2014 Elsevier Inc. All rights reserved.

Internet Access in the European Union and in the United States.

ERIC Educational Resources Information Center

Bauer, Johannes M.; Berne, Michel; Maitland, Carleen F.

2002-01-01

Examines the effects of public policies towards traditional communications infrastructures on Internet access in Europe and the United States. Discusses competitive strategies and describes the influence of regulatory policies affecting market entry and the pricing of services on Internet access, based on empirical findings. (Author/LRW)

Refugee Resettlement Patterns and State-Level Health Care Insurance Access in the United States.

PubMed

Agrawal, Pooja; Venkatesh, Arjun Krishna

2016-04-01

We sought to evaluate the relationship between state-level implementation of the Patient Protection and Affordable Care Act (ACA) and resettlement patterns among refugees. We linked federal refugee resettlement data to ACA expansion data and found that refugee resettlement rates are not significantly different according to state-level insurance expansion or cost. Forty percent of refugees have resettled to states without Medicaid expansion. The wide state-level variability in implementation of the ACA should be considered by federal agencies seeking to optimize access to health insurance coverage among refugees who have resettled to the United States.

Refugee Resettlement Patterns and State-Level Health Care Insurance Access in the United States

PubMed Central

Venkatesh, Arjun Krishna

2016-01-01

We sought to evaluate the relationship between state-level implementation of the Patient Protection and Affordable Care Act (ACA) and resettlement patterns among refugees. We linked federal refugee resettlement data to ACA expansion data and found that refugee resettlement rates are not significantly different according to state-level insurance expansion or cost. Forty percent of refugees have resettled to states without Medicaid expansion. The wide state-level variability in implementation of the ACA should be considered by federal agencies seeking to optimize access to health insurance coverage among refugees who have resettled to the United States. PMID:26890186

State High School Graduation Requirements and Access to Postsecondary Education

ERIC Educational Resources Information Center

Stanton, Roseanna

2010-01-01

This study examined the relationship between state policies mandating increased mathematics credits for high school graduation and access to postsecondary education. The purpose of this study was to determine if the state policy intervention of increasing high school mathematics requirements was related to a higher likelihood that students would…

Study of uranium oxidation states in geological material.

PubMed

Pidchenko, I; Salminen-Paatero, S; Rothe, J; Suksi, J

2013-10-01

A wet chemical method to determine uranium (U) oxidation states in geological material has been developed and tested. The problem faced in oxidation state determinations with wet chemical methods is that U redox state may change when extracted from the sample material, thereby leading to erroneous results. In order to quantify and monitor U redox behavior during the acidic extraction in the procedure, an analysis of added isotopic redox tracers, (236)U(VI) and (232)U(IV), and of variations in natural uranium isotope ratio ((234)U/(238)U) of indigenous U(IV) and U(VI) fractions was performed. Two sample materials with varying redox activity, U bearing rock and U-rich clayey lignite sediment, were used for the tests. The Fe(II)/Fe(III) redox-pair of the mineral phases was postulated as a potentially disturbing redox agent. The impact of Fe(III) on U was studied by reducing Fe(III) with ascorbic acid, which was added to the extraction solution. We observed that ascorbic acid protected most of the U from oxidation. The measured (234)U/(238)U ratio in U(IV) and U(VI) fractions in the sediment samples provided a unique tool to quantify U oxidation caused by Fe(III). Annealing (sample heating) to temperatures above 500 °C was supposed to heal ionizing radiation induced defects in the material that can disturb U redox state during extraction. Good agreement between two independent methods was obtained for DL-1a material: an average 38% of U(IV) determined by redox tracer corrected wet chemistry and 45% for XANES. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nanoscale chemical state analysis of resistance random access memory device reacting with Ti

NASA Astrophysics Data System (ADS)

Shima, Hisashi; Nakano, Takashi; Akinaga, Hiro

2010-05-01

The thermal stability of the resistance random access memory material in the reducing atmosphere at the elevated temperature was improved by the addition of Ti. The unipolar resistance switching before and after the postdeposition annealing (PDA) process at 400 °C was confirmed in Pt/CoO/Ti(5 nm)/Pt device, while the severe degradation of the initial resistance occurs in the Pt/CoO/Pt and Pt/CoO/Ti(50 nm)/Pt devices. By investigating the chemical bonding states of Co, O, and Ti using electron energy loss spectroscopy combined with transmission electron microscopy, it was revealed that excess Ti induces the formation of metallic Co, while the thermal stability was improved by trace Ti. Moreover, it was indicated that the filamentary conduction path can be thermally induced after PDA in the oxide layer by analyzing electrical properties of the degraded devices. The adjustment of the reducing elements is quite essential in order to participate in their profits.

Park Access Among School-Age Youth in the United States.

PubMed

Harris, Carmen D; Paul, Prabasaj; Young, Randall; Zhang, Xingyou; Fulton, Janet E

2015-06-01

Fewer than 30% of U.S. youth meet the recommendation to be active ≥ 60 minutes/day. Access to parks may encourage higher levels of physical activity. To examine differences in park access among U.S. school-age youth, by demographic characteristics and urbanicity of block group. Park data from 2012 were obtained from TomTom, Incorporated. Population data were obtained from the 2010 U.S. Census and American Community Survey 2006-2010. Using a park access score for each block group based on the number of national, state or local parks within one-half mile, we examined park access among youth by majority race/ethnicity, median household income, median education, and urbanicity of block groups. Overall, 61.3% of school-age youth had park access--64.3% in urban, 36.5% in large rural, 37.8% in small rural, and 35.8% in isolated block groups. Park access was higher among youth in block groups with higher median household income and higher median education. Urban youth are more likely to have park access. However, park access also varies by race/ethnicity, median education, and median household. Considering both the demographics and urbanicity may lead to better characterization of park access and its association with physical activity among youth.

Mapping the Iron Oxidation State in Martian Meteorites

NASA Technical Reports Server (NTRS)

Martin, A. M.; Treimann, A. H.; Righter, K.

2017-01-01

Several types of Martian igneous meteorites have been identified: clinopyroxenites (nakhlites), basaltic shergottites, peridotitic shergottites, dunites (chassignites) and orthopyroxenites [1,2]. In order to constrain the heterogeneity of the Martian mantle and crust, and their evolution through time, numerous studies have been performed on the iron oxidation state of these meteorites [3,4,5,6,7,8,9]. The calculated fO2 values all lie within the FMQ-5 to FMQ+0.5 range (FMQ representing the Fayalite = Magnetite + Quartz buffer); however, discrepancies appear between the various studies, which are either attributed to the choice of the minerals/melts used, or to the precision of the analytical/calculation method. The redox record in volcanic samples is primarily related to the oxidation state in the mantle source(s). However, it is also influenced by several deep processes: melting, crystallization, magma mixing [10], assimilation and degassing [11]. In addition, the oxidation state in Martian meteorites is potentially affected by several surface processes: assimilation of sediment/ crust during lava flowing at Mars' surface, low temperature micro-crystallization [10], weathering at the surface of Mars and low temperature reequilibration, impact processes (i.e. high pressure phase transitions, mechanical mixing, shock degassing and melting), space weathering, and weathering on Earth (at atmospheric conditions different from Mars). Decoding the redox record of Martian meteorites, therefore, requires large-scale quantitative analysis methods, as well as a perfect understanding of oxidation processes.

Oxidative Stress and Heart Failure in Altered Thyroid States

PubMed Central

Mishra, Pallavi; Samanta, Luna

2012-01-01

Increased or reduced action of thyroid hormone on certain molecular pathways in the heart and vasculature causes relevant cardiovascular derangements. It is well established that hyperthyroidism induces a hyperdynamic cardiovascular state, which is associated with a faster heart rate, enhanced left ventricular systolic and diastolic function whereas hypothyroidism is characterized by the opposite changes. Hyperthyroidism and hypothyroidism represent opposite clinical conditions, albeit not mirror images. Recent experimental and clinical studies have suggested the involvement of ROS tissue damage under altered thyroid status. Altered-thyroid state-linked changes in heart modify their susceptibility to oxidants and the extent of the oxidative damage they suffer following oxidative challenge. Chronic increase in the cellular levels of ROS can lead to a catastrophic cycle of DNA damage, mitochondrial dysfunction, further ROS generation and cellular injury. Thus, these cellular events might play an important role in the development and progression of myocardial remodeling and heart failure in altered thyroid states (hypo- and hyper-thyroidism). The present review aims at elucidating the various signaling pathways mediated via ROS and their modulation under altered thyroid state and the possibility of antioxidant therapy. PMID:22649319

Population-based geographic access to endocrinologists in the United States, 2012.

PubMed

Lu, Hua; Holt, James B; Cheng, Yiling J; Zhang, Xingyou; Onufrak, Stephen; Croft, Janet B

2015-12-07

Increases in population and life expectancy of Americans may result in shortages of endocrinologists by 2020. This study aims to assess variations in geographic accessibility to endocrinologists in the US, by age group at state and county levels, and by urban/rural status, and distance. We used the 2012 National Provider Identifier Registry to obtain office locations of all adult and pediatric endocrinologists in the US. The population with geographic access to an endocrinologist within a series of 6 distance radii, centered on endocrinologist practice locations, was estimated using the US Census 2010 block-level population. We assumed that persons living within the same circular buffer zone of an endocrinologist location have the same geographic accessibility to that endocrinologist. The geographic accessibility (the percentage of the population with geographic access to at least one endocrinologist) and the population-to-endocrinologist ratio for each geographic area were estimated. By using 20 miles as the distance radius, geographic accessibility to at least one pediatric/adult endocrinologist for age groups 0-17, 18-64, and ≥ 65 years was 64.1%, 85.4%, and 82.1%. The overall population-to-endocrinologist ratio within 20 miles was 39,492:1 for children, 29,887:1 for adults aged 18-64 years, and 6,194:1 for adults aged ≥ 65 years. These ratios varied considerably by state, county, urban/rural status, and distance. This study demonstrates that there are geographic variations of accessibility to endocrinologists in the US. The areas with poorer geographic accessibility warrant further study of the effect of these variations on disease prevention, detection, and management of endocrine diseases in the US population. Our findings of geographic access to endocrinologists also may provide valuable information for medical education and health resources allocation.

22 CFR 9b.1 - Press access to the Department of State.

Code of Federal Regulations, 2012 CFR

2012-04-01

... BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid... enjoyed by members of the public. (b) Media correspondents holding valid Department of State press... the Department of State building. (c) Media correspondents, with or without a Department of State...

22 CFR 9b.1 - Press access to the Department of State.

Code of Federal Regulations, 2013 CFR

2013-04-01

... BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid... enjoyed by members of the public. (b) Media correspondents holding valid Department of State press... the Department of State building. (c) Media correspondents, with or without a Department of State...

22 CFR 9b.1 - Press access to the Department of State.

Code of Federal Regulations, 2011 CFR

2011-04-01

... BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid... enjoyed by members of the public. (b) Media correspondents holding valid Department of State press... the Department of State building. (c) Media correspondents, with or without a Department of State...

22 CFR 9b.1 - Press access to the Department of State.

Code of Federal Regulations, 2014 CFR

2014-04-01

... BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid... enjoyed by members of the public. (b) Media correspondents holding valid Department of State press... the Department of State building. (c) Media correspondents, with or without a Department of State...

22 CFR 9b.1 - Press access to the Department of State.

Code of Federal Regulations, 2010 CFR

2010-04-01

... BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid... enjoyed by members of the public. (b) Media correspondents holding valid Department of State press... the Department of State building. (c) Media correspondents, with or without a Department of State...

Photochemical oxidants: state of the science.

PubMed

Kley, D; Kleinmann, M; Sanderman, H; Krupa, S

1999-01-01

Atmospheric photochemical processes resulting in the production of tropospheric ozone (O(3)) and other oxidants are described. The spatial and temporal variabilities in the occurrence of surface level oxidants and their relationships to air pollution meteorology are discussed. Models of photooxidant formation are reviewed in the context of control strategies and comparisons are provided of the air concentrations of O(3) at select geographic locations around the world. This overall oxidant (O(3)) climatology is coupled to human health and ecological effects. The discussion of the effects includes both acute and chronic responses, mechanisms of action, human epidemiological and plant population studies and briefly, efforts to establish cause-effect relationships through numerical modeling. A short synopsis is provided of the interactive effects of O(3) with other abiotic and biotic factors. The overall emphasis of the paper is on identifying the current uncertainties and gaps in our understanding of the state of the science and some suggestions as to how they may be addressed.

Facile Access to Graphene Oxide from Ferro-Induced Oxidation

NASA Astrophysics Data System (ADS)

Yu, Chao; Wang, Cai-Feng; Chen, Su

2016-01-01

Methods allowing the oxidation of graphite to graphene oxide (GO) are vital important for the production of graphene from GO. This oxidation reaction has mainly relied on strong acid strategy for 174 years, which circumvents issues associated with toxicity of reagent and product, complex post-treatment, high cost and waste generation. Here, we report a green route for performing this oxidization reaction via a ferro-induced strategy, with use of water, potassium ferrate (Fe(VI)) and hydrogen peroxide (H2O2) as reagents, to produce about 65% yield of GO (vs. 40% for Hummers’ method, the most commonly used concentrated acid strategy) and non-toxic by-products. Moreover, GO produced from this new method shows equivalent performance to those reported previously. This H2SO4-free strategy makes it possible to process graphite into GO in a safe, low-cost, time-saving, energy-efficient and eco-friendly pathway, opening a promising avenue for the large-scale production of GO and GO-based materials.

Facile Access to Graphene Oxide from Ferro-Induced Oxidation.

PubMed

Yu, Chao; Wang, Cai-Feng; Chen, Su

2016-01-28

Methods allowing the oxidation of graphite to graphene oxide (GO) are vital important for the production of graphene from GO. This oxidation reaction has mainly relied on strong acid strategy for 174 years, which circumvents issues associated with toxicity of reagent and product, complex post-treatment, high cost and waste generation. Here, we report a green route for performing this oxidization reaction via a ferro-induced strategy, with use of water, potassium ferrate (Fe(VI)) and hydrogen peroxide (H2O2) as reagents, to produce about 65% yield of GO (vs. 40% for Hummers' method, the most commonly used concentrated acid strategy) and non-toxic by-products. Moreover, GO produced from this new method shows equivalent performance to those reported previously. This H2SO4-free strategy makes it possible to process graphite into GO in a safe, low-cost, time-saving, energy-efficient and eco-friendly pathway, opening a promising avenue for the large-scale production of GO and GO-based materials.

Facile Access to Graphene Oxide from Ferro-Induced Oxidation

PubMed Central

Yu, Chao; Wang, Cai-Feng; Chen, Su

2016-01-01

Methods allowing the oxidation of graphite to graphene oxide (GO) are vital important for the production of graphene from GO. This oxidation reaction has mainly relied on strong acid strategy for 174 years, which circumvents issues associated with toxicity of reagent and product, complex post-treatment, high cost and waste generation. Here, we report a green route for performing this oxidization reaction via a ferro-induced strategy, with use of water, potassium ferrate (Fe(VI)) and hydrogen peroxide (H2O2) as reagents, to produce about 65% yield of GO (vs. 40% for Hummers’ method, the most commonly used concentrated acid strategy) and non-toxic by-products. Moreover, GO produced from this new method shows equivalent performance to those reported previously. This H2SO4-free strategy makes it possible to process graphite into GO in a safe, low-cost, time-saving, energy-efficient and eco-friendly pathway, opening a promising avenue for the large-scale production of GO and GO-based materials. PMID:26818784

A Pyridine Alkoxide Chelate Ligand That Promotes Both Unusually High Oxidation States and Water-Oxidation Catalysis

DOE PAGES

Michaelos, Thoe K.; Shopov, Dimitar Y.; Sinha, Shashi Bhushan; ...

2017-03-08

Here, water-oxidation catalysis is a critical bottleneck in the direct generation of solar fuels by artificial photosynthesis. Catalytic oxidation of difficult substrates such as water requires harsh conditions, so that the ligand must be designed both to stabilize high oxidation states of the metal center and to strenuously resist ligand degradation. Typical ligand choices either lack sufficient electron donor power or fail to stand up to the oxidizing conditions. This research on Ir-based water-oxidation catalysts (WOCs) has led us to identify a ligand, 2-(2'-pyridyl)-2-propanoate or “pyalk” that fulfills these requirements.

Mantle redox evolution and the oxidation state of the Archean atmosphere

NASA Technical Reports Server (NTRS)

Kasting, J. F.; Eggler, D. H.; Raeburn, S. P.

1993-01-01

Current models predict that the early atmosphere consisted mostly of CO2, N2, and H2O, along with traces of H2 and CO. Such models are based on the assumption that the redox state of the upper mantle has not changed, so that volcanic gas composition has remained approximately constant with time. We argue here that this assumption is probably incorrect: the upper mantle was originally more reduced than today, although not as reduced as the metal arrest level, and has become progressively more oxidized as a consequence of the release of reduced volcanic gases and the subduction of hydrated, oxidized seafloor. Data on the redox state of sulfide and chromite inclusions in diamonds imply that the process of mantle oxidation was slow, so that reduced conditions could have prevailed for as much as half of the earth's history. To be sure, other oxybarometers of ancient rocks give different results, so the question of when the mantle redox state has changed remains unresolved. Mantle redox evolution is intimately linked to the oxidation state of the primitive atmosphere: A reduced Archean atmosphere would have had a high hydrogen escape rate and should correspond to a changing mantle redox state; an oxidized Archean atmosphere should be associated with a constant mantle redox state. The converses of these statements are also true. Finally, our theory of mantle redox evolution may explain why the Archean atmosphere remained oxygen-deficient until approximately 2.0 billion years ago (Ga) despite a probable early origin for photosynthesis.

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

PubMed

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

2013-05-28

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

Expanded Definition of the Oxidation State

ERIC Educational Resources Information Center

Loock, Hans-Peter

2011-01-01

A proposal to define the oxidation state of an atom in a compound as the hypothetical charge of the corresponding atomic ion that is obtained by heterolytically cleaving its bonds such that the atom with the higher electronegativity in a bond is allocated all electrons in the bond. Bonds between like atoms are cleaved homolytically. This…

Natural Variation in the Carbon Oxidation State and Oxidative Ratio of a Deciduous Forest

NASA Astrophysics Data System (ADS)

Masiello, C. A.; Calligan, L. J.; Gallagher, M. E.; Hockaday, W. C.; Robertson, G. P.

2007-12-01

Here we report natural variability in the oxidative ratio (OR) and carbon oxidation state (Cox) of a temperate, deciduous forest measured on an annual basis via elemental analysis of leaf litter. The OR of the terrestrial biosphere is a key component in O2 -based calculations of the biosphere's uptake of fossil fuel CO2 (eg [ Keeling, et al., 1996]). Ecosystem OR has been assumed to be invariant; however, small OR variations may cause significant shifts in the calculated size of the terrestrial biospheric C sink [ Randerson, et al., 2006]. Accurate measurements of OR are necessary for the accurate apportionment of fossil fuel CO2 between the atmosphere, oceans, and terrestrial biosphere. Ecosystem OR is linearly related to Cox, a parameter which can be easily measured via elemental analysis, calorimetry, or solid state nuclear magnetic resonance [ Masiello, et al., 2007]. We are measuring Cox and OR at the three deciduous forest sites within the Kellogg Biological Station NSF LTER (lter.kbs.msu.edu). We report OR from litter collected from three forest sites from 1998-2003, a time series which covers periods of both normal and low precipitation. We also report error introduced in the Cox to OR conversion via a range of plausible assumptions about ecosystem N cycling. Keeling, R. F., et al. (1996), Global and hemispheric CO2 sinks deduced from changes in atmospheric O2 concentration, Nature, 381, 218-221. Masiello, C.A. et al. (in review 2007) Two new approaches for measuring ecosystem carbon oxidation state and oxidative ratio. J.G.R. Biogeosciences. Randerson, J. T., et al. (2006), Is carbon within the global terrestrial biosphere becoming more oxidized? Implications for trends in atmospheric O2, Global Change Biology, 12, 260-271.

About structural phase state of coating based on zirconium oxide formed by microplasma oxidation method

NASA Astrophysics Data System (ADS)

Gubaidulina, Tatiana A.; Sergeev, Viktor P.; Kuzmin, Oleg S.; Fedorischeva, Marina V.; Kalashnikov, Mark P.

2017-12-01

The oxide-ceramic coating based of zirconium oxide is formed by the method of microplasma oxidation. The producing modes of the oxide layers on E110 zirconium alloy are under testing. It was found that using microplasma treatment of E110 zirconium in aluminosilicate electrolyte makes possible the formation of porous oxide-ceramic coatings based on zirconium alloyed by aluminum and niobium. The study is focused on the modes how to form heat-shielding coatings with controlled porosity and minimal amount of microcracks. The structural-phase state of the coating is studied by X-ray diffraction analysis and scanning electron microscopy (SEM). It was found that the ratio of the monoclinic and tetragonal phases changes with the change occurring in the coating formation modes.

Oxygenic Photosynthesis and the Oxidation State of Mars

NASA Technical Reports Server (NTRS)

Hartman, Hyman; McKay, Christopher P.

1995-01-01

The oxidation state of the Earth's surface is one of the most obvious indications of the effect of life on this planet. The surface of Mars is highly oxidized, as evidenced by its red color, but the connection to life is less apparent. Two possibilities can be considered. First, the oxidant may be photochemically produced in the atmosphere. In this case the fundamental source of O2 is the loss of H2 to space and the oxidant produced is H2O2. This oxidant would accumulate on the surface and thereby destroy any organic material and other reductants to some depth. Recent models suggest that diffusion limits this depth to a few meters. An alternative source of oxygen is biological oxygen production followed by sequestration of organic material in sediments - as on the Earth. In this case, the net oxidation of the surface was determined billions of years ago when Mars was a more habitable planet and oxidative conditions could persist to great depths, over 100 m. Below this must be a compensating layer of biogenic organic material. Insight into the nature of past sources of oxidation on Mars will require searching for organics in the martian subsurface and sediments.

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

PubMed Central

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

2013-01-01

Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn3+/Mn4+ ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states. PMID:23667149

State Medicaid fees and access to primary care physicians.

PubMed

Sharma, Rajiv; Tinkler, Sarah; Mitra, Arnab; Pal, Sudeshna; Susu-Mago, Raven; Stano, Miron

2018-03-01

Medicaid and uninsured patients are disadvantaged in access to care and are disproportionately Black and Hispanic. Using a national audit of primary care physicians, we examine the relationship between state Medicaid fees for primary care services and access for Medicaid, Medicare, uninsured, and privately insured patients who differ by race/ethnicity and sex. We found that states with higher Medicaid fees had higher probabilities of appointment offers and shorter wait times for Medicaid patients, and lower probabilities of appointment offers and longer wait times for uninsured patients. Appointment offers and wait times for Medicare and privately insured patients were unaffected by Medicaid fees. At mean state Medicaid fees, our analysis predicts a 27-percentage-point disadvantage for Medicaid versus Medicare in appointment offers. This decreases to 6 percentage points when Medicaid and Medicare fees are equal, suggesting that permanent fee parity with Medicare could eliminate most of the disparity in appointment offers for Medicaid patients. The predicted decrease in the disparity is smaller for Black and Hispanic patients than for White patients. Our research highlights the importance of considering the effects of policy on nontarget patient groups, and the consequences of seemingly race-neutral policies on racial/ethnic and sex-based disparities. Copyright © 2017 John Wiley & Sons, Ltd.

A Stateful Multicast Access Control Mechanism for Future Metro-Area-Networks.

ERIC Educational Resources Information Center

Sun, Wei-qiang; Li, Jin-sheng; Hong, Pei-lin

2003-01-01

Multicasting is a necessity for a broadband metro-area-network; however security problems exist with current multicast protocols. A stateful multicast access control mechanism, based on MAPE, is proposed. The architecture of MAPE is discussed, as well as the states maintained and messages exchanged. The scheme is flexible and scalable. (Author/AEF)

Oxide films state analysis by IR spectroscopy based on the simple oscillator approximation

NASA Astrophysics Data System (ADS)

Volkov, N. V.; Yakutkina, T. V.; Karpova, V. V.

2017-05-01

Stabilization of structure-phase state in a wide temperature range is one of the most important problems of improving properties of oxide compounds. As such, the search of new effective methods for obtaining metal oxides with desired physic-chemical, electro-physical and thermal properties and their control is important and relevant. The aim of this work is identification features state of the oxide films of some metals Be, Al, Fe, Cu, Zr on the metal surface of the polycrystalline samples by infrared spectroscopy. To identify the resonance emission bands the algorithm of IR-spectra processing was developed and realized on the basis of table processor EXCEL-2010, which allow revealing characteristic resonance bands successfully and identification of inorganic chemical compounds. In the frame of simple oscillator model, resonance frequencies of normal vibrations of water and some inorganic compounds: metal oxides - Be, Al, Fe, Cu, Zr were calculated and characteristic frequencies for different states (aggregate, deformation, phase) were specified. By means of IR-spectroscopy fundamental possibility of revealing oxides films on metal substrate features state is shown, that allow development and optimization of the technology for production of the oxide films with desired properties.

State of the practice on data access, sharing, and integration.

DOT National Transportation Integrated Search

2016-12-01

The purpose of this state-of-the-practice review was to lay both technical and institutional foundation for all aspects of the development of the Virtual Data Access Framework. The review focused on current data sharing and integration practices amon...

[Indigenous peoples' access to health services in Cuiabá, Mato Grosso State, Brazil].

PubMed

Gomes, Silvana Cardoso; Esperidião, Monique Azevedo

2017-06-12

This study aimed to evaluate indigenous peoples' access to medium and high-complexity health services in the municipality of Cuiabá, Mato Grosso State, Brazil, through the Casa de Saúde Indígena or Indigenous Peoples' Clinic (CASAI Cuiabá). A single case study with a qualitative approach was conducted at CASAI Cuiabá. Data were obtained from observation of the work routines at CASAI Cuiabá, semi-structured interviews with health professionals and administrators from the Cuiabá Special Indigenous Health District (DSEI) and CASAI Cuiabá, and document analysis. Data analysis used a matrix derived from the theoretical and logical model of accessibility, validated by the Delphi method with a group of experts on indigenous peoples' health. Despite advances achieved by CASAI in improving indigenous peoples' access, there are persistent social, organizational, cultural, and geographic barriers in access to medium and high-complexity health services in Cuiabá. The study highlights the need for specific strategies to improve access to health services by indigenous peoples in Mato Grosso State.

Interactive access to forest inventory data for the South Central United States

Treesearch

William H. McWilliams

1990-01-01

On-line access to USDA, Forest Service successive forest inventory data for the South Central United States is provided by two computer systems. The Easy Access to Forest Inventory and Analysis Tables program (EZTAB) produces a set of tables for specific geographic areas. The Interactive Graphics and Retrieval System (INGRES) is a database management system that...

A spontaneous change in the oxidation states of Pd/WO3 toward an active phase during catalytic cycles of CO oxidation

NASA Astrophysics Data System (ADS)

Jeon, Byungwook; Kim, Ansoon; Lee, Young-Ahn; Seo, Hyungtak; Kim, Yu Kwon

2017-11-01

CO oxidation over Pd/WO3 films prepared on a glass substrate has been examined at the substrate temperature of 150 - 250 °C and pressures less than 1 Torr with a stoichiometric mixture of CO and O2. Under the given reaction condition, the chemical states of the Pd/WO3 film gradually change into the most catalytically active form with the highest saturation reaction rate regardless of the initial oxidation states. The measured CO oxidation rate over the Pd/WO3 is strongly dependent on the chemical states of Pd and W. Either metallic Pd or fully oxidized PdO phase is not as catalytically active as the active form with mixed metallic Pd and thin PdO layers supported on WO3 with partially reduced W5+ state which is spontaneously obtained during the catalytic reaction cycles. Our results indicate that the facile oxygen transfer between Pd and WO3 layers not only facilitate the spontaneous changes into the active form, but also act as a promotional role in CO oxidation over the Pd layer.

Differentiation of Sclerotinia minor depends on thiol redox state and oxidative stress.

PubMed

Patsoukis, Nikolaos; Georgiou, Christos D

2008-01-01

Sclerotial differentiation in Sclerotinia minor is associated with oxidative stress and thiol redox state. The significance of oxidative stress to sclerotial differentiation was revealed by the higher oxidative stress of S. minor compared with a nonsclerotiogenic counterpart. The effect of thiol redox state on sclerotial differentiation was shown by the antioxidant action of the thiol (-SH) group of N-acetylcysteine and cysteine and by an unknown (not antioxidant) role of glutathione (GSH) on S. minor. The nonantioxidant role of GSH was indicated by the differentiation-inhibiting and differentiation-noninhibiting actions of the GSH biosynthesis inhibitor L-buthionine-S,R-sulfoximine and the GSH biosynthesis inducer L-2-oxo-thiazolidine-4-carboxylate, respectively, and by the increase of oxidative stress they caused during the transition from the undifferentiated to differentiated state of S. minor. Moreover, N-acetylcysteine can be used as a potent nontoxic fungicide against this phytopathogenic fungus by acting as a growth-inhibiting cytotoxic oxidant and by sustaining the fungus in the undifferentiated hyphal stage, which is vulnerable to degradation by soil microorganisms.

Heterogeneous Oxidation of Atmospheric Organic Aerosol: Kinetics of Changes to the Amount and Oxidation State of Particle-Phase Organic Carbon.

PubMed

Kroll, Jesse H; Lim, Christopher Y; Kessler, Sean H; Wilson, Kevin R

2015-11-05

Atmospheric oxidation reactions are known to affect the chemical composition of organic aerosol (OA) particles over timescales of several days, but the details of such oxidative aging reactions are poorly understood. In this study we examine the rates and products of a key class of aging reaction, the heterogeneous oxidation of particle-phase organic species by the gas-phase hydroxyl radical (OH). We compile and reanalyze a number of previous studies from our laboratories involving the oxidation of single-component organic particles. All kinetic and product data are described on a common basis, enabling a straightforward comparison among different chemical systems and experimental conditions. Oxidation chemistry is described in terms of changes to key ensemble properties of the OA, rather than to its detailed molecular composition, focusing on two quantities in particular, the amount and the oxidation state of the particle-phase carbon. Heterogeneous oxidation increases the oxidation state of particulate carbon, with the rate of increase determined by the detailed chemical mechanism. At the same time, the amount of particle-phase carbon decreases with oxidation, due to fragmentation (C-C scission) reactions that form small, volatile products that escape to the gas phase. In contrast to the oxidation state increase, the rate of carbon loss is nearly uniform among most systems studied. Extrapolation of these results to atmospheric conditions indicates that heterogeneous oxidation can have a substantial effect on the amount and composition of atmospheric OA over timescales of several days, a prediction that is broadly in line with available measurements of OA evolution over such long timescales. In particular, 3-13% of particle-phase carbon is lost to the gas phase after one week of heterogeneous oxidation. Our results indicate that oxidative aging represents an important sink for particulate organic carbon, and more generally that fragmentation reactions play a major

Microanalysis of iron oxidation states in earth and planetary materials

NASA Astrophysics Data System (ADS)

Bajt, S.; Sutton, S. R.; Delaney, J. S.

1995-02-01

Initial studies have been made on quantifying Fe oxidation states in different iron-bearing minerals using K-edge XANES. The energy of a weak pre-edge peak in the XANES spectrum due to 1s-3d electron transition was used to quantify ferric/ferrous ratios with microprobe spatial resolution. The estimated accuracy of the technique was +/- 10% in terms of Fe3+/((Fe2+ + Fe3+)). The detection limit was ~ 100 ppm with a synchrotron beam of ~ 100 μm in diameter. The pre-edge peak energy in well-characterized samples with known Fe oxidation states was found to be a linear function of the ferric/(ferrous) ratio. The technique was applied to altered magnetics (ideally Fe3O4), and various silicates and oxides from meteorites.

Characterization of Interface State in Silicon Carbide Metal Oxide Semiconductor Capacitors

NASA Astrophysics Data System (ADS)

Kao, Wei-Chieh

Silicon carbide (SiC) has always been considered as an excellent material for high temperature and high power devices. Since SiC is the only compound semiconductor whose native oxide is silicon dioxide (SiO2), it puts SiC in a unique position. Although SiC metal oxide semiconductor (MOS) technology has made significant progress in recent years, there are still a number of issues to be overcome before more commercial SiC devices can enter the market. The prevailing issues surrounding SiC MOSFET devices are the low channel mobility, the low quality of the oxide layer and the high interface state density at the SiC/SiO2 interface. Consequently, there is a need for research to be performed in order to have a better understanding of the factors causing the poor SiC/SiO2 interface properties. In this work, we investigated the generation lifetime in SiC materials by using the pulsed metal oxide semiconductor (MOS) capacitor method and measured the interface state density distribution at the SiC/SiO2 interface by using the conductance measurement and the high-low frequency capacitance technique. These measurement techniques have been performed on n-type and p-type SiC MOS capacitors. In the course of our investigation, we observed fast interface states at semiconductor-dielectric interfaces in SiC MOS capacitors that underwent three different interface passivation processes, such states were detected in the nitrided samples but not observed in PSG-passivated samples. This result indicate that the lack of fast states at PSG-passivated interface is one of the main reasons for higher channel mobility in PSG MOSFETs. In addition, the effect of mobile ions in the oxide on the response time of interface states has been investigated. In the last chapter we propose additional methods of investigation that can help elucidate the origin of the particular interface states, enabling a more complete understanding of the SiC/SiO2 material system.

METHOD OF MAINTAINING PLUTONIUM IN A HIGHER STATE OF OXIDATION DURING PROCESSING

DOEpatents

Thompson, S.G.; Miller, D.R.

1959-06-30

This patent deals with the oxidation of tetravalent plutonium contained in an aqueous acid solution together with fission products to the hexavalent state, prior to selective fission product precipitation, by adding to the solution bismuthate or ceric ions as the oxidant and a water-soluble dichromate as a holding oxidant. Both oxidant and holding oxidant are preferably added in greater than stoichiometric quantities with regard to the plutonium present.

A national assessment of public recreational access on family forestlands in the United States

Treesearch

Stephanie A. Snyder; Brett J. Butler

2012-01-01

Private forestlands in the United States are important for public recreation, but access to them may be threatened. Using the US Forest Service's National Woodland Owner Survey, we examined the following questions: (1) How prevalent is public recreational access on family forestland? (2) What influences whether a family forest owner allows public access? (3) Are...

Trap States of the Oxide Thin Film Transistor

NASA Astrophysics Data System (ADS)

Yu, Kyeong Min; Yuh, Jin Tae; Park, Sang Hee Ko; Ryu, Min Ki; Yun, Eui Jung; Bae, Byung Seong

2013-10-01

We investigated the temperature dependent recovery of the threshold voltage shift observed in both ZnO and indium gallium zinc oxide (IGZO) thin film transistors (TFTs) after application of gate bias and light illumination. Two types of recovery were observed for both the ZnO and IGZO TFTs; low temperature recovery (below 110 °C) which is attributed to the trapped charge and high temperature recovery (over 110 °C) which is related to the annihilation of trap states generated during stresses. From a comparison study of the recovery rate with the analysis of hydrogen diffusion isochronal annealing, a similar behavior was observed for both TFT recovery and hydrogen diffusion. This result suggests that hydrogen plays an important role in the generation and annihilation of trap states in oxide TFTs under gate bias or light illumination stresses.

Geographic Accessibility of Pulmonologists for Adults With COPD: United States, 2013.

PubMed

Croft, Janet B; Lu, Hua; Zhang, Xingyou; Holt, James B

2016-09-01

Geographic clusters in prevalence and hospitalizations for COPD have been identified at national, state, and county levels. The study objective is to identify county-level geographic accessibility to pulmonologists for adults with COPD. Service locations of 12,392 practicing pulmonologists and 248,160 primary care physicians were identified from the 2013 National Provider Identifier Registry and weighted by census block-level populations within a series of circular distance buffer zones. Model-based county-level population counts of US adults ≥ 18 years of age with COPD were estimated from the 2013 Behavioral Risk Factor Surveillance System. The percentages of all estimated adults with potential access to at least one provider type and the county-level ratio of adults with COPD per pulmonologist were estimated for selected distances. Most US adults (100% in urbanized areas, 99.5% in urban clusters, and 91.7% in rural areas) had geographic access to a primary care physician within a 10-mile buffer distance; almost all (≥ 99.9%) had access to a primary care physician within 50 miles. At least one pulmonologist within 10 miles was available for 97.5% of US adults living in urbanized areas, but only for 38.3% in urban clusters and 34.5% in rural areas. When distance increased to 50 miles, at least one pulmonologist was available for 100% in urbanized areas, 93.2% in urban clusters, and 95.2% in rural areas. County-level ratios of adults with COPD per pulmonologist varied greatly across the United States, with residents in many counties in the Midwest having no pulmonologist within 50 miles. County-level geographic variations in pulmonologist access for adults with COPD suggest that those adults with limited access will have to depend on care from primary care physicians. Published by Elsevier Inc.

Control of cerium oxidation state through metal complex secondary structures

DOE PAGES

Levin, Jessica R.; Dorfner, Walter L.; Carroll, Patrick J.; ...

2015-08-11

A series of alkali metal cerium diphenylhydrazido complexes, M x(py) y[Ce(PhNNPh) 4], M = Li, Na, and K, x = 4 (Li and Na) or 5 (K), and y = 4 (Li), 8 (Na), or 7 (K), were synthesized to probe how a secondary coordination sphere would modulate electronic structures at a cerium cation. The resulting electronic structures of the heterobimetallic cerium diphenylhydrazido complexes were found to be strongly dependent on the identity of the alkali metal cations. When M = Li + or Na +, the cerium(III) starting material was oxidized with concomitant reduction of 1,2-diphenylhydrazine to aniline. Reductionmore » of 1,2-diphenylhydrazine was not observed when M = K +, and the complex remained in the cerium(III) oxidation state. Oxidation of the cerium(III) diphenylhydrazido complex to the Ce( IV) diphenylhydrazido one was achieved through a simple cation exchange reaction of the alkali metals. As a result, UV-Vis spectroscopy, FTIR spectroscopy, electrochemistry, magnetic susceptibility, and DFT studies were used to probe the oxidation state and the electronic changes that occurred at the metal centre.« less

Optoelectronic properties of valence-state-controlled amorphous niobium oxide

NASA Astrophysics Data System (ADS)

Onozato, Takaki; Katase, Takayoshi; Yamamoto, Akira; Katayama, Shota; Matsushima, Koichi; Itagaki, Naho; Yoshida, Hisao; Ohta, Hiromichi

2016-06-01

In order to understand the optoelectronic properties of amorphous niobium oxide (a-NbO x ), we have investigated the valence states, local structures, electrical resistivity, and optical absorption of a-NbO x thin films with various oxygen contents. It was found that the valence states of Nb ion in a-NbO x films can be controlled from 5+  to 4+  by reducing oxygen pressure during film deposition at room temperature, together with changing the oxide-ion arrangement around Nb ion from Nb2O5-like to NbO2-like local structure. As a result, a four orders of magnitude reduction in the electrical resistivity of a-NbO x films was observed with decreasing oxygen content, due to the carrier generation caused by the appearance and increase of an oxygen-vacancy-related subgap state working as an electron donor. The tunable optoelectronic properties of a-NbO x films by valence-state-control with oxygen-vacancy formation will be useful for potential flexible optoelectronic device applications.

Oxidation of extracellular cysteine/cystine redox state in bleomycin-induced lung fibrosis.

PubMed

Iyer, Smita S; Ramirez, Allan M; Ritzenthaler, Jeffrey D; Torres-Gonzalez, Edilson; Roser-Page, Susanne; Mora, Ana L; Brigham, Kenneth L; Jones, Dean P; Roman, Jesse; Rojas, Mauricio

2009-01-01

Several lines of evidence indicate that depletion of glutathione (GSH), a critical thiol antioxidant, is associated with the pathogenesis of idiopathic pulmonary fibrosis (IPF). However, GSH synthesis depends on the amino acid cysteine (Cys), and relatively little is known about the regulation of Cys in fibrosis. Cys and its disulfide, cystine (CySS), constitute the most abundant low-molecular weight thiol/disulfide redox couple in the plasma, and the Cys/CySS redox state (E(h) Cys/CySS) is oxidized in association with age and smoking, known risk factors for IPF. Furthermore, oxidized E(h) Cys/CySS in the culture media of lung fibroblasts stimulates proliferation and expression of transitional matrix components. The present study was undertaken to determine whether bleomycin-induced lung fibrosis is associated with a decrease in Cys and/or an oxidation of the Cys/CySS redox state and to determine whether these changes were associated with changes in E(h) GSH/glutathione disulfide (GSSG). We observed distinct effects on plasma GSH and Cys redox systems during the progression of bleomycin-induced lung injury. Plasma E(h) GSH/GSSG was selectively oxidized during the proinflammatory phase, whereas oxidation of E(h) Cys/CySS occurred at the fibrotic phase. In the epithelial lining fluid, oxidation of E(h) Cys/CySS was due to decreased food intake. Thus the data show that decreased precursor availability and enhanced oxidation of Cys each contribute to the oxidation of extracellular Cys/CySS redox state in bleomycin-induced lung fibrosis.

Oxidation of extracellular cysteine/cystine redox state in bleomycin-induced lung fibrosis

PubMed Central

Iyer, Smita S.; Ramirez, Allan M.; Ritzenthaler, Jeffrey D.; Torres-Gonzalez, Edilson; Roser-Page, Susanne; Mora, Ana L.; Brigham, Kenneth L.; Jones, Dean P.; Roman, Jesse; Rojas, Mauricio

2009-01-01

Several lines of evidence indicate that depletion of glutathione (GSH), a critical thiol antioxidant, is associated with the pathogenesis of idiopathic pulmonary fibrosis (IPF). However, GSH synthesis depends on the amino acid cysteine (Cys), and relatively little is known about the regulation of Cys in fibrosis. Cys and its disulfide, cystine (CySS), constitute the most abundant low-molecular weight thiol/disulfide redox couple in the plasma, and the Cys/CySS redox state (Eh Cys/CySS) is oxidized in association with age and smoking, known risk factors for IPF. Furthermore, oxidized Eh Cys/CySS in the culture media of lung fibroblasts stimulates proliferation and expression of transitional matrix components. The present study was undertaken to determine whether bleomycin-induced lung fibrosis is associated with a decrease in Cys and/or an oxidation of the Cys/CySS redox state and to determine whether these changes were associated with changes in Eh GSH/glutathione disulfide (GSSG). We observed distinct effects on plasma GSH and Cys redox systems during the progression of bleomycin-induced lung injury. Plasma Eh GSH/GSSG was selectively oxidized during the proinflammatory phase, whereas oxidation of Eh Cys/CySS occurred at the fibrotic phase. In the epithelial lining fluid, oxidation of Eh Cys/CySS was due to decreased food intake. Thus the data show that decreased precursor availability and enhanced oxidation of Cys each contribute to the oxidation of extracellular Cys/CySS redox state in bleomycin-induced lung fibrosis. PMID:18931052

Geography Matters: State-Level Variation in Children's Oral Health Care Access and Oral Health Status

PubMed Central

Fisher-Owens, Susan A.; Soobader, Mah-J; Gansky, Stuart A.; Isong, Inyang A.; Weintraub, Jane A.; Platt, Larry J.; Newacheck, Paul W.

2016-01-01

Objectives To ascertain differences across states in children's oral health care access and oral health status and the factors that contribute to those differences Study Design Observational study using cross-sectional surveys Methods Using the 2007 National Survey of Children's Health, we examined state variation in parent's report of children's oral health care access (absence of a preventive dental visit) and oral health status. We assessed the unadjusted prevalences of these outcomes, then adjusted with child-, family-, and neighborhood-level variables using logistic regression; these results are presented directly and graphically. Using multilevel analysis, we then calculated the degree to which child-, family-, and community-level variables explained state variation. Finally, we quantified the influence of state-level variables on state variation. Results Unadjusted rates of no preventive dental care ranged 9.0-26.8% (mean 17.5%), with little impact of adjusting (10.3-26.7%). Almost 9% of population had fair/poor oral health; unadjusted range 4.1-14.5%. Adjusting analyses affected fair/poor oral health more than access (5.7-10.7%). Child, family and community factors explained ~¼ of the state variation in no preventive visit and ~½ of fair/poor oral health. State-level factors further contributed to explaining up to a third of residual state variation. Conclusion Geography matters: where a child lives has a large impact on his or her access to oral health care and oral health status, even after adjusting for child, family, community, and state variables. As state-level variation persists, other factors and richer data are needed to clarify the variation and drive changes for more egalitarian and overall improved oral health. PMID:26995567

Engineering the Ground State of Complex Oxides

NASA Astrophysics Data System (ADS)

Meyers, Derek Joseph

Transition metal oxides featuring strong electron-electron interactions have been at the forefront of condensed matter physics research in the past few decades due to the myriad of novel and exciting phases derived from their competing interactions. Beyond their numerous intriguing properties displayed in the bulk they have also shown to be quite susceptible to externally applied perturbation in various forms. The dominant theme of this work is the exploration of three emerging methods for engineering the ground states of these materials to access both their applicability and their deficiencies. The first of the three methods involves a relatively new set of compounds which adhere to a unique paradigm in chemical doping, a-site ordered perovskites. These compounds are iso-structural, i.e. constant symmetry, despite changing the dopant ions. We find that these materials, featuring Cu at the doped A-site, display the Zhang-Rice state, to varying degrees, found in high temperature superconducting cuprates, with the choice of B-site allowing "self-doping" within the material. Further, we find that within CaCu3Ir 4O12 the Cu gains a localized magnetic moment and leads to the experimentally observed heavy fermion state in the materials, one of only two such non-f-electron heavy fermion materials. Next, epitaxial constraint is used to modify the ground state of the rare-earth nickelates in ultra thin film form. Application of compressive (tensile) strain is found to suppress (maintain) the temperature at which the material goes through a Mott metal-insulator transition. Further, while for EuNiO3 thin films the typical bulk-like magnetic and charge ordering is found to occur, epitaxial strain is found to suppress the charge ordering in NdNiO3 thin films due to pinning to the substrate and the relatively weak tendency to monoclinically distort. Finally, the creation of superlattices of EuNiO3 and LaNiO3 was shown to not only allow the selection of the temperature at which

Equity Access Plans: A Regulatory and Educational State Response Model.

ERIC Educational Resources Information Center

DeLisle, James

1984-01-01

Introduces the basic notion of equity access plans as property-based solutions to the cash flow needs of elderly homeowners and then proposes a normative response model that states can adopt to help manage the risk exposures. The recommended model incorporates regulatory, information dissemination, and educational elements. (BH)

State Financial Aid to Students: A Trend Analysis of Access and Choice of Public or Private Colleges.

ERIC Educational Resources Information Center

Fenske, Robert H.; And Others

1979-01-01

Reports trends over a recent nine-year period in student access to and choice of public or private college as related to availability of monetary awards from one of the largest state student financial aid agencies, the Illinois State Scholarship Commission. Survey responses indicate that state awards foster access to Illinois college and…

Unified computational model of transport in metal-insulating oxide-metal systems

NASA Astrophysics Data System (ADS)

Tierney, B. D.; Hjalmarson, H. P.; Jacobs-Gedrim, R. B.; Agarwal, Sapan; James, C. D.; Marinella, M. J.

2018-04-01

A unified physics-based model of electron transport in metal-insulator-metal (MIM) systems is presented. In this model, transport through metal-oxide interfaces occurs by electron tunneling between the metal electrodes and oxide defect states. Transport in the oxide bulk is dominated by hopping, modeled as a series of tunneling events that alter the electron occupancy of defect states. Electron transport in the oxide conduction band is treated by the drift-diffusion formalism and defect chemistry reactions link all the various transport mechanisms. It is shown that the current-limiting effect of the interface band offsets is a function of the defect vacancy concentration. These results provide insight into the underlying physical mechanisms of leakage currents in oxide-based capacitors and steady-state electron transport in resistive random access memory (ReRAM) MIM devices. Finally, an explanation of ReRAM bipolar switching behavior based on these results is proposed.

Geography matters: state-level variation in children's oral health care access and oral health status.

PubMed

Fisher-Owens, S A; Soobader, M J; Gansky, S A; Isong, I A; Weintraub, J A; Platt, L J; Newacheck, P W

2016-05-01

To ascertain differences across states in children's oral health care access and oral health status and the factors that contribute to those differences. Observational study using cross-sectional surveys. Using the 2007 National Survey of Children's Health, we examined state variation in parents' report of children's oral health care access (absence of a preventive dental visit) and oral health status. We assessed the unadjusted prevalences of these outcomes, then adjusted with child-, family-, and neighbourhood-level variables using logistic regression; these results are presented directly and graphically. Using multilevel analysis, we then calculated the degree to which child-, family-, and community-level variables explained state variation. Finally, we quantified the influence of state-level variables on state variation. Unadjusted rates of no preventive dental care ranged 9.0-26.8% (mean 17.5%), with little impact of adjusting (10.3-26.7%). Almost 9% of the population had fair/poor oral health; unadjusted range 4.1-14.5%. Adjusting analyses affected fair/poor oral health more than access (5.7-10.7%). Child, family and community factors explained ∼¼ of the state variation in no preventive visit and ∼½ of fair/poor oral health. State-level factors further contributed to explaining up to a third of residual state variation. Geography matters: where a child lives has a large impact on his or her access to oral health care and oral health status, even after adjusting for child, family, community, and state variables. As state-level variation persists, other factors and richer data are needed to clarify the variation and drive changes for more egalitarian and overall improved oral health. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Disparities in access to emergency general surgery care in the United States.

PubMed

Khubchandani, Jasmine A; Shen, Connie; Ayturk, Didem; Kiefe, Catarina I; Santry, Heena P

2018-02-01

As fewer surgeons take emergency general surgery call and hospitals decrease emergency services, a crisis in access looms in the United States. We examined national emergency general surgery capacity and county-level determinants of access to emergency general surgery care with special attention to disparities. To identify potential emergency general surgery hospitals, we queried the database of the American Hospital Association for "acute care general hospital," with "surgical services," and "emergency department," and ≥1 "operating room." Internet search and direct contact confirmed emergency general surgery services that covered the emergency room 7 days a week, 24 hours a day. Geographic and population-level emergency general surgery access was derived from Geographic Information Systems and US Census. Of the 6,356 hospitals in the 2013 American Hospital Association database, only 2,811 were emergency general surgery hospitals. Counties with greater percentages of black, Hispanic, uninsured, and low-education individuals and rural counties disproportionately lacked access to emergency general surgery care. For example, counties above the 75th percentile of African American population (10.2%) had >80% odds of not having an emergency general surgery hospital compared with counties below the 25th percentile of African American population (0.6%). Gaps in access to emergency general surgery services exist across the United States, disproportionately affecting underserved, rural communities. Policy initiatives need to increase emergency general surgery capacity nationwide. Copyright © 2017 Elsevier Inc. All rights reserved.

Ferric Iron Production in Magma Oceans and Evolution of Mantle Oxidation State

NASA Astrophysics Data System (ADS)

Schaefer, L.; Elkins-Tanton, L. T.; Pahlevan, K.

2018-05-01

Self-oxidation of the magma ocean by ferric iron production at high pressure may explain the mantle oxidation state of the Earth. Partitioning during fractional crystallization can further increase the mantle oxygen fugacity during solidification.

The Oxidation State of Europium in Halide Glasses

PubMed Central

Weber, J.K.R.; Vu, M.; Paßlick, C.; Schweizer, S.; Brown, D.E.; Johnson, C.E.; Johnson, J.A.

2012-01-01

The luminescent properties of divalent europium ions can be exploited to produce storage phosphors for x-ray imaging applications. The relatively high cost and limited availability of divalent europium halides makes it desirable to synthesize them from the readily available trivalent salts. In this work, samples of pure EuCl3 and fluoride glass melts doped with EuCl3 were processed at 700-800 °C in an inert atmosphere furnace. The Eu oxidation state in the resulting materials was determined using fluorescence and Mössbauer spectroscopy. Heat treatment of pure EuCl3 for 10 minutes at 710 °C resulted in a material comprising approximately equal amounts of Eu2+ and Eu3+. Glasses made using mixtures of EuCl2 and EuCl3 in the starting material contained both oxidation states. This paper describes the sample preparation and analysis and discusses the results in the context of chemical equilibria in the melts. PMID:22101252

Access to Care for Youth in a State Mental Health System: A Simulated Patient Approach.

PubMed

Olin, Su-Chin Serene; O'Connor, Briannon C; Storfer-Isser, Amy; Clark, Lisa J; Perkins, Matthew; Hudson Scholle, Sarah; Whitmyre, Emma D; Hoagwood, Kimberly; Horwitz, Sarah McCue

2016-05-01

To examine access to psychiatric care for adolescents with depression in outpatient specialty clinics within a state mental health system, using a simulated patient approach. Trained callers posed as the mother of a 14-year-old girl with depression, following a script. A stratified random sample (n = 264) of 340 state-licensed outpatient mental health clinics that serve youth was selected. Clinics were randomly assigned to season and insurance condition. We examined whether access varied by season, clinic characteristics, and caller insurance type. Weighted logistic and linear mixed effects regression models were fitted to examine associations with appointment availability and wait times. Among clinics at which a treatment appointment could be scheduled, appointment availability differed by season. Clinics that had participated in state-sponsored trainings targeting access were more available. Wait times for treatment appointments varied by season and region. Wait times in New York City were shorter than in some other regions. Although callers were 4.1 times more likely to be able to schedule a psychiatry appointment in the spring, wait times for psychiatry appointments were significantly longer in the spring than in the summer (49.9 vs. 36.7 days). Wait times for therapy appointments were significantly shorter in community than in hospital clinics (19.1 days vs. 35.3 days). Access to psychiatric care for youth with depression was found to be variable in a state system. State-sponsored trainings on strategies to reduce wait times appear to improve care access. The simulated patient approach has promise for monitoring the impact of health care policy reforms on care quality measures. Published by Elsevier Inc.

Access to Care for Youth in a State Mental Health System: A Simulated Patient Approach

PubMed Central

Olin, Su-chin Serene; O'Connor, Briannon C.; Storfer-Isser, Amy; Clark, Lisa J.; Perkins, Matthew; Scholle, Sarah Hudson; Whitmyre, Emma D.; Hoagwood, Kimberly; Horwitz, Sarah McCue

2016-01-01

Objective To examine access to psychiatric care for adolescents with depression in outpatient specialty clinics within a state mental health system, using a simulated patient approach. Method Trained callers posed as the mother of a 14-year-old female with depression, following a script. A stratified random sample (n = 264) of 340 state-licensed outpatient mental health clinics that serve youth was selected. Clinics were randomly assigned to season and insurance condition. We examined if access varied by season, clinic characteristics, and caller insurance type. Weighted logistic and linear mixed effects regression models were fitted to examine associations with appointment availability and wait times. Results Among clinics where a treatment appointment could be scheduled, appointment availability differed by season. Clinics who had participated in state-sponsored trainings targeting access were more available. Wait times for treatment appointments varied by season and region. Wait times in New York City were shorter than in some other regions. Although callers were 4.1 times more likely to be able to schedule a psychiatry appointment in the spring, wait times for psychiatry appointments were significantly longer in the spring than in the summer (49.9 vs. 36.7 days). Wait times for therapy appointments were significantly shorter in community than hospital clinics (19.1 days vs. 35.3 days). Conclusion Access to psychiatric care for youth with depression was found to be variable in a state system. State-sponsored trainings on strategies to reduce wait times appear to improve care access. The simulated patient approach has promise for monitoring the impact of healthcare policy reforms on care quality measures. PMID:27126853

MRI based on iron oxide nanoparticles contrast agents: effect of oxidation state and architecture

NASA Astrophysics Data System (ADS)

Javed, Yasir; Akhtar, Kanwal; Anwar, Hafeez; Jamil, Yasir

2017-11-01

Iron oxide nanoparticles (IONPs) extensively employed beyond regenerative medicines to imaging disciplines because of their great constituents for magneto-responsive nano-systems. The unique superparamagnetic behavior makes IONPs very suitable for hyperthermia and imaging applications. From the last decade, versatile functionalization with surface capabilities, efficient contrast properties and biocompatibilities make IONPs an essential imaging contrast agent for magnetic resonance imaging (MRI). IONPs have shown signals for both longitudinal relaxation and transverse relaxation; therefore, negative contrast as well as dual contrast can be used for imaging in MRI. In the current review, we have focused on different oxidation state of iron oxides, i.e., magnetite, maghemite and hematite for their T1 and T2 contrast enhancement properties. We have also discussed different factors (synthesis protocols, biocompatibility, toxicity, architecture, etc.) that can affect the contrast properties of the IONPs. [Figure not available: see fulltext.

15N and 31P solid-state NMR study of transmembrane domain alignment of M2 protein of influenza A virus in hydrated cylindrical lipid bilayers confined to anodic aluminum oxide nanopores.

PubMed

Chekmenev, Eduard Y; Hu, Jun; Gor'kov, Peter L; Brey, William W; Cross, Timothy A; Ruuge, Andres; Smirnov, Alex I

2005-04-01

This communication reports the first example of a high resolution solid-state 15N 2D PISEMA NMR spectrum of a transmembrane peptide aligned using hydrated cylindrical lipid bilayers formed inside nanoporous anodic aluminum oxide (AAO) substrates. The transmembrane domain SSDPLVVA(A-15N)SIIGILHLILWILDRL of M2 protein from influenza A virus was reconstituted in hydrated 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine bilayers that were macroscopically aligned by a conventional micro slide glass support or by the AAO nanoporous substrate. 15N and 31P NMR spectra demonstrate that both the phospholipids and the protein transmembrane domain are uniformly aligned in the nanopores. Importantly, nanoporous AAO substrates may offer several advantages for membrane protein alignment in solid-state NMR studies compared to conventional methods. Specifically, higher thermal conductivity of aluminum oxide is expected to suppress thermal gradients associated with inhomogeneous radio frequency heating. Another important advantage of the nanoporous AAO substrate is its excellent accessibility to the bilayer surface for exposure to solute molecules. Such high accessibility achieved through the substrate nanochannel network could facilitate a wide range of structure-function studies of membrane proteins by solid-state NMR.

In-situ determination of the oxidation state of iron in Fe-bearing silicate melts

NASA Astrophysics Data System (ADS)

Courtial, P.; Wilke, M.; Potuzak, M.; Dingwell, D. B.

2005-12-01

Terrestrial lavas commonly contain up to 10 wt% of iron. Furthermore, rocks returned from the Moon indicate lunar lava containing up to 25 wt% of iron and planetary scientists estimated that the martian mantle has about 18 wt% of iron. An experimental challenge in dealing with Fe-bearing silicate melts is that the oxidation state, controlling the proportions of ferric and ferrous iron, is a function of composition, oxygen fugacity and temperature and may vary significantly. Further complications concerning iron originate from its potential to be either four-, six- or even five-fold coordinated in both valence states. Therefore, the oxidation state of iron was determined in air for various Fe-bearing silicate melts. Investigated samples were Na-disilicate (NS), one atmosphere anorthite-diopside eutectic (AD) and haplogranitic (HPG8) melts containing up to 20, 20 and 10 wt% of iron, respectively. XANES spectra at the Fe K-edge were collected for all the melts at beamline A1, HASYLAB, Hamburg, using a Si(111) 4-crystal monochromator. Spectra were collected for temperatures up to 1573 K using a Pt-Rh loop as heating device. The Fe oxidation state was determined from the centroid position of the pre-edge feature using the calibration of Wilke et al. (2004). XANES results suggest that oxidation state of iron does not change within error for NS melts with addition of Fe, while AD and HPG8 melts become more oxidised with increasing iron content. Furthermore, NS melts are well more oxidised than AD and HPG8 melts that exhibit relatively similar oxidation states for identical iron contents. The oxidation state of iron for NS melts appears to be slightly temperature-dependent within the temperature range investigated (1073-1573 K). However, this trend is stronger for AD and HPG8 melts. Assuming that glass reflects a picture of the homogeneous equilibria of the melt, the present in-situ Fe-oxidation states determined for these melts were compared to those obtained on quenched

Information Access in Rural Areas of the United States: The Public Library's Role in the Digital Divide and the Implications of Differing State Funding Models

ERIC Educational Resources Information Center

Thiele, Jennifer

2016-01-01

In the United States, individual states have different means of determining and distributing funding. This influences library service and access to information particularly as it pertains to critical Internet access. Funding and service trends have changed, especially as it relates to public libraries, with some modifications working to their…

Redox-Active Bis(phenolate) N-Heterocyclic Carbene [OCO] Pincer Ligands Support Cobalt Electron Transfer Series Spanning Four Oxidation States.

PubMed

Harris, Caleb F; Bayless, Michael B; van Leest, Nicolaas P; Bruch, Quinton J; Livesay, Brooke N; Bacsa, John; Hardcastle, Kenneth I; Shores, Matthew P; de Bruin, Bas; Soper, Jake D

2017-10-16

A new family of low-coordinate Co complexes supported by three redox-noninnocent tridentate [OCO] pincer-type bis(phenolate) N-heterocyclic carbene (NHC) ligands are described. Combined experimental and computational data suggest that the charge-neutral four-coordinate complexes are best formulated as Co(II) centers bound to closed-shell [OCO] 2- dianions, of the general formula [(OCO)Co II L] (where L is a solvent-derived MeCN or THF). Cyclic voltammograms of the [(OCO)Co II L] complexes reveal three oxidations accessible at potentials below 1.2 V vs Fc + /Fc, corresponding to generation of formally Co(V) species, but the true physical/spectroscopic oxidation states are much lower. Chemical oxidations afford the mono- and dications of the imidazoline NHC-derived complex, which were examined by computational and magnetic and spectroscopic methods, including single-crystal X-ray diffraction. The metal and ligand oxidation states of the monocationic complex are ambiguous; data are consistent with formulation as either [( S OCO)Co III (THF) 2 ] + containing a closed-shell [ S OCO] 2- diphenolate ligand bound to a S = 1 Co(III) center, or [( S OCO • )Co II (THF) 2 ] + with a low-spin Co(II) ion ferromagnetically coupled to monoanionic [ S OCO • ] - containing a single unpaired electron distributed across the [OCO] framework. The dication is best described as [( S OCO 0 )Co II (THF) 3 ] 2+ , with a single unpaired electron localized on the d 7 Co(II) center and a doubly oxidized, charge-neutral, closed-shell S OCO 0 ligand. The combined data provide for the first time unequivocal and structural evidence for [OCO] ligand redox activity. Notably, varying the degree of unsaturation in the NHC backbone shifts the ligand-based oxidation potentials by up to 400 mV. The possible chemical origins of this unexpected shift, along with the potential utility of the [OCO] pincer ligands for base-metal-mediated organometallic coupling catalysis, are discussed.

The digital divide in public e-health: barriers to accessibility and privacy in state health department websites.

PubMed

West, Darrell M; Miller, Edward Alan

2006-08-01

State health departments have placed a tremendous amount of information, data, and services online in recent years. With the significant increase in online resources at official health sites, though, have come questions concerning equity of access and the confidentiality of electronic medical materials. This paper reports on an examination of public health department websites maintained by the 50 state governments. Using a content analysis of health department sites undertaken each year from 2000 to 2005, we investigate several dimensions of accessibility and privacy: readability levels, disability access, non-English accessibility, and the presence of privacy and security statements. We argue that although progress has been made at improving the accessibility and confidentiality of health department electronic resources, there remains much work to be done to ensure quality access for all Americans in the area of public e-health.

State parity laws and access to treatment for substance use disorder in the United States: implications for federal parity legislation.

PubMed

Wen, Hefei; Cummings, Janet R; Hockenberry, Jason M; Gaydos, Laura M; Druss, Benjamin G

2013-12-01

The passage of the 2008 Mental Health Parity and Addiction Equity Act and the 2010 Affordable Care Act incorporated parity for substance use disorder (SUD) treatment into federal legislation. However, prior research provides us with scant evidence as to whether federal parity legislation will hold the potential for improving access to SUD treatment. To examine the effect of state-level SUD parity laws on state-aggregate SUD treatment rates and to shed light on the impact of the recent federal SUD parity legislation. We conducted a quasi-experimental study using a 2-way (state and year) fixed-effect method. We included all known specialty SUD treatment facilities in the United States and examined treatment rates from October 1, 2000, through March 31, 2008. Our main source of data was the National Survey of Substance Abuse Treatment Services, which provides facility-level information on specialty SUD treatment. State-level SUD parity laws during the study period. State-aggregate SUD treatment rates in (1) all specialty SUD treatment facilities and (2) specialty SUD treatment facilities accepting private insurance. The implementation of any SUD parity law increased the treatment rate by 9% (P < .001) in all specialty SUD treatment facilities and by 15% (P = .02) in facilities accepting private insurance. Full parity and parity only if SUD coverage is offered increased the SUD treatment rate by 13% (P = .02) and 8% (P = .04), respectively, in all facilities and by 21% (P = .03) and 10% (P = .04), respectively, in facilities accepting private insurance. We found a positive effect of the implementation of state SUD parity legislation on access to specialty SUD treatment. Furthermore, the positive association is more pronounced in states with more comprehensive parity laws. Our findings suggest that federal parity legislation holds the potential to improve access to SUD treatment.

State Parity Laws and Access to Treatment for Substance Use Disorder in the United States: Implications for Federal Parity Legislation

PubMed Central

Wen, Hefei; Cummings, Janet R.; Hockenberry, Jason M.; Gaydos, Laura M.; Druss, Benjamin G.

2014-01-01

Context The passage of the 2008 Mental Health Parity and Addiction Equity Act (MHPAEA) and the 2010 Affordable Care Act (ACA) incorporated parity for substance use disorder (SUD) into federal legislation. Yet prior research provides us with scant evidence as to whether federal parity legislation will hold the potential for improving access to SUD treatment. Objective This study examined the effect of state-level SUD parity laws on state-aggregate SUD treatment rates from 2000 to 2008, to shed light on the impact of the recent federal-level SUD parity legislation. Design A quasi-experimental study design using a two-way (state and year) fixed-effect method Setting and Participants All known specialty SUD treatment facilities in the United States Interventions State-level SUD parity laws between 2000 and 2008 Main Outcome Measures State-aggregate SUD treatment rates in: (1) all specialty SUD treatment facilities, and (2) specialty SUD treatment facilities accepting private insurance Results The implementation of any SUD parity law increased the treatment rate by 9 percent (p<0.01) in all specialty SUD treatment facilities and by 15 percent (p<0.05) in facilities accepting private insurance. Full parity and parity-if-offered (i.e., parity only if SUD coverage is offered) increased SUD treatment rate by 13 percent (p<0.05) and 8 percent (p<0.05) in all facilities, and by 21 percent (p<0.05) and 10 percent (p<0.05) in those accepting private insurance. Conclusions We found a positive effect of the implementation of state SUD parity legislation on access to specialty SUD treatment. Furthermore, the positive association was more pronounced in states with more comprehensive parity laws. Our findings suggest that federal parity legislation holds the potential to improve access to SUD treatment. PMID:24154931

Access to Care for Methadone Maintenance Patients in the United States

ERIC Educational Resources Information Center

Hettema, Jennifer E.; Sorensen, James L.

2009-01-01

This policy commentary addresses a significant access to care issue that faces methadone maintenance patients seeking residential treatment in the United States. Methadone maintenance therapy (MMT) has demonstrated strong efficacy in the outpatient treatment of opiate dependence. However, many opiate dependent patients are also in need of more…

Educational Effects of Banning Access to In-State Resident Tuition for Unauthorized Immigrant Students

ERIC Educational Resources Information Center

Villarraga-Orjuela, Alexander; Kerr, Brinck

2017-01-01

This research examines the effects of state laws banning access to in-state resident tuition for unauthorized immigrant students in the United States. These laws were implemented between 2005 and 2012. We evaluate the policy effects on (a) college enrollment, (b) school dropout rates of unauthorized immigrants, and (c) the enrollment of U.S.…

The mitochondrial oxidoreductase CHCHD4 is present in a semi-oxidized state in vivo.

PubMed

Erdogan, Alican J; Ali, Muna; Habich, Markus; Salscheider, Silja L; Schu, Laura; Petrungaro, Carmelina; Thomas, Luke W; Ashcroft, Margaret; Leichert, Lars I; Roma, Leticia Prates; Riemer, Jan

2018-07-01

Disulfide formation in the mitochondrial intermembrane space is an essential process catalyzed by a disulfide relay machinery. In mammalian cells, the key enzyme in this machinery is the oxidoreductase CHCHD4/Mia40. Here, we determined the in vivo CHCHD4 redox state, which is the major determinant of its cellular activity. We found that under basal conditions, endogenous CHCHD4 redox state in cultured cells and mouse tissues was predominantly oxidized, however, degrees of oxidation in different tissues varied from 70% to 90% oxidized. To test whether differences in the ratio between CHCHD4 and ALR might explain tissue-specific differences in the CHCHD4 redox state, we determined the molar ratio of both proteins in different mouse tissues. Surprisingly, ALR is superstoichiometric over CHCHD4 in most tissues. However, the levels of CHCHD4 and the ratio of ALR over CHCHD4 appear to correlate only weakly with the redox state, and although ALR is present in superstoichiometric amounts, it does not lead to fully oxidized CHCHD4. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Solid oxide fuel cells fueled with reducible oxides

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

Chuang, Steven S.; Fan, Liang Shih

A direct-electrochemical-oxidation fuel cell for generating electrical energy includes a cathode provided with an electrochemical-reduction catalyst that promotes formation of oxygen ions from an oxygen-containing source at the cathode, a solid-state reduced metal, a solid-state anode provided with an electrochemical-oxidation catalyst that promotes direct electrochemical oxidation of the solid-state reduced metal in the presence of the oxygen ions to produce electrical energy, and an electrolyte disposed to transmit the oxygen ions from the cathode to the solid-state anode. A method of operating a solid oxide fuel cell includes providing a direct-electrochemical-oxidation fuel cell comprising a solid-state reduced metal, oxidizing themore » solid-state reduced metal in the presence of oxygen ions through direct-electrochemical-oxidation to obtain a solid-state reducible metal oxide, and reducing the solid-state reducible metal oxide to obtain the solid-state reduced metal.« less

Excited-State Dynamics of Biological Molecules in Solution: Photoinduced Charge Transfer in Oxidatively Damaged DNA and Deactivation of Violacein in Viscous Solvents

NASA Astrophysics Data System (ADS)

Beckstead, Ashley Ann

UV radiation from the sun is strongly absorbed by DNA, and the resulting electronic excited states can lead to the formation of mutagenic photoproducts. Decades of research have brought to light the excited-state dynamics of single RNA and DNA nucleobases, but questions remain about the nature of excited states accessed in DNA strands. In this thesis, I present ultrafast spectroscopic observations of photoinduced electron transfer from the oxidatively damaged bases, 8-oxo-7,8-dihydro-2'-deoxyguanosine, 5-hydroxy-2'-deoxycytidine and 5-hydroxy-2'-deoxyuridine, to adenine in three dinucleotides. The results reveal that charge transfer states are formed on a timescale faster than our instrumental resolution (<0.5 ps), and back electron transfer efficiently returns the excited-state population to the ground state on timescales from tens to hundreds of ps. In addition to recent spectroscopic observations of charge transfer state species in DNA by other groups, our results have augmented understanding of the long-lived transient signals observed in DNA strands. The observation of photoinduced electron transfer in these oxidatively damaged nucleobases also supports a recent proposal regarding the role of oxidative products in pre-RNA catalysis. I discuss these observations in the contexts of fundamental DNA excited-state dynamics and prebiotic chemical evolution. In this thesis, I also present the first ultrafast spectroscopic investigation of violacein, a pigment isolated from Antarctic bacteria. Despite claims for the photoprotective role of this pigment, there has never been a spectroscopic analysis of excited-state deactivation in violacein. Emission spectra, fluorescence quantum yields and excited-state lifetimes of violacein in various solvents were measured for the first time. Both the fluorescence quantum yield and excited-state lifetime of violacein increase in increasingly viscous solvents, suggesting a large-scale motion mediates excited-state deactivation. I

Arsenic (+3 Oxidation State) Methyltransferase and the Methylation of Arsenicals

PubMed Central

Thomas, David J.; Li, Jiaxin; Waters, Stephen B.; Xing, Weibing; Adair, Blakely M.; Drobna, Zuzana; Devesa, Vicenta; Styblo, Miroslav

2008-01-01

Metabolic conversion of inorganic arsenic into methylated products is a multistep process that yields mono-, di-, and trimethylated arsenicals. In recent years, it has become apparent that formation of methylated metabolites of inorganic arsenic is not necessarily a detoxification process. Intermediates and products formed in this pathway may be more reactive and toxic than inorganic arsenic. Like all metabolic pathways, understanding the pathway for arsenic methylation involves identification of each individual step in the process and the characterization of the molecules which participate in each step. Among several arsenic methyltransferases that have been identified, arsenic (+3 oxidation state) methyltransferase is the one best characterized at the genetic and functional levels. This review focuses on phylogenetic relationships in the deuterostomal lineage for this enzyme and on the relation between genotype for arsenic (+3 oxidation state) methyltransferase and phenotype for conversion of inorganic arsenic to methylated metabolites. Two conceptual models for function of arsenic (+3 oxidation state) methyltransferase which posit different roles for cellular reductants in the conversion of inorganic arsenic to methylated metabolites are compared. Although each model accurately represents some aspects of enzyme’s role in the pathway for arsenic methylation, neither model is a fully satisfactory representation of all the steps in this metabolic pathway. Additional information on the structure and function of the enzyme will be needed to develop a more comprehensive model for this pathway. PMID:17202581

GaAs-oxide interface states - Gigantic photoionization via Auger-like process

NASA Technical Reports Server (NTRS)

Lagowski, J.; Kazior, T. E.; Gatos, H. C.; Walukiewicz, W.; Siejka, J.

1981-01-01

Spectral and transient responses of photostimulated current in MOS structures were employed for the study of GaAs-anodic oxide interface states. Discrete deep traps at 0.7 and 0.85 eV below the conduction band were found with concentrations of 5 x 10 to the 12th/sq cm and 7 x 10 to the 11th/sq cm, respectively. These traps coincide with interface states induced on clean GaAs surfaces by oxygen and/or metal adatoms (submonolayer coverage). In contrast to surfaces with low oxygen coverage, the GaAs-thick oxide interfaces exhibited a high density (about 10 to the 14th/sq cm) of shallow donors and acceptors. Photoexcitation of these donor-acceptor pairs led to a gigantic photoionization of deep interface states with rates 1000 times greater than direct transitions into the conduction band. The gigantic photoionization is explained on the basis of energy transfer from excited donor-acceptor pairs to deep states.

Oxidation state and interfacial effects on oxygen vacancies in tantalum pentoxide

DOE PAGES

Bondi, Robert J.; Marinella, Matthew J.

2015-02-28

First-principles density-functional theory (DFT) calculations are used to study the atomistic structure, structural energetics, and electron density near the O monovacancy (V O n; n=0,1+,2+) in both bulk, amorphous tantalum pentoxide (a-Ta 2O 5) and also at vacuum and metallic Ta interfaces. We calculate multivariate vacancy formation energies to evaluate stability as a function of oxidation state, distance from interface plane, and Fermi energy. V O n of all oxidation states preferentially segregate at both Ta and vacuum interfaces, where the metallic interface exhibits global formation energy minima. In a-Ta 2O 5, V O 0 are characterized by structural contractionmore » and electron density localization, while V O 2+ promote structural expansion and are depleted of electron density. In contrast, interfacial V O 0 and V O 2+ show nearly indistinguishable ionic and electronic signatures indicative of a reduced V O center. Interfacial V O 2+ extract electron density from metallic Ta indicating V O 2+ is spontaneously reduced at the expense of the metal. This oxidation/reduction behavior suggests careful selection and processing of both oxide layer and metal electrodes for engineering memristor device operation.« less

Model for determination of mid-gap states in amorphous metal oxides from thin film transistors

NASA Astrophysics Data System (ADS)

Bubel, S.; Chabinyc, M. L.

2013-06-01

The electronic density of states in metal oxide semiconductors like amorphous zinc oxide (a-ZnO) and its ternary and quaternary oxide alloys with indium, gallium, tin, or aluminum are different from amorphous silicon, or disordered materials such as pentacene, or P3HT. Many ZnO based semiconductors exhibit a steep decaying density of acceptor tail states (trap DOS) and a Fermi level (EF) close to the conduction band energy (EC). Considering thin film transistor (TFT) operation in accumulation mode, the quasi Fermi level for electrons (Eq) moves even closer to EC. Classic analytic TFT simulations use the simplification EC-EF> `several'kT and cannot reproduce exponential tail states with a characteristic energy smaller than 1/2 kT. We demonstrate an analytic model for tail and deep acceptor states, valid for all amorphous metal oxides and include the effect of trap assisted hopping instead of simpler percolation or mobility edge models, to account for the observed field dependent mobility.

Photochemical route for accessing amorphous metal oxide materials for water oxidation catalysis.

PubMed

Smith, Rodney D L; Prévot, Mathieu S; Fagan, Randal D; Zhang, Zhipan; Sedach, Pavel A; Siu, Man Kit Jack; Trudel, Simon; Berlinguette, Curtis P

2013-04-05

Large-scale electrolysis of water for hydrogen generation requires better catalysts to lower the kinetic barriers associated with the oxygen evolution reaction (OER). Although most OER catalysts are based on crystalline mixed-metal oxides, high activities can also be achieved with amorphous phases. Methods for producing amorphous materials, however, are not typically amenable to mixed-metal compositions. We demonstrate that a low-temperature process, photochemical metal-organic deposition, can produce amorphous (mixed) metal oxide films for OER catalysis. The films contain a homogeneous distribution of metals with compositions that can be accurately controlled. The catalytic properties of amorphous iron oxide prepared with this technique are superior to those of hematite, whereas the catalytic properties of a-Fe(100-y-z)Co(y)Ni(z)O(x) are comparable to those of noble metal oxide catalysts currently used in commercial electrolyzers.

[Public control and equity of access to hospitals under non-State public administration].

PubMed

Carneiro Junior, Nivaldo; Elias, Paulo Eduardo

2006-10-01

To analyze social health organizations in the light of public control and the guarantee of equity of access to health services. Utilizing the case study technique, two social health organizations in the metropolitan region of São Paulo were selected. The analytical categories were equity of access and public control, and these were based on interviews with key informants and technical-administrative reports. It was observed that the overall funding and administrative control of the social health organizations are functions of the state administrator. The presence of a local administrator is important for ensuring equity of access. Public control is expressed through supervisory actions, by means of accounting and financial procedures. Equity of access and public control are not taken into consideration in the administration of these organizations. The central question lies in the capacity of the public authorities to have a presence in implementing this model at the local level, thereby ensuring equity of access and taking public control into consideration.

Crystallographic studies of [NiFe]-hydrogenase mutants: towards consensus structures for the elusive unready oxidized states.

PubMed

Volbeda, Anne; Martin, Lydie; Barbier, Elodie; Gutiérrez-Sanz, Oscar; De Lacey, Antonio L; Liebgott, Pierre-Pol; Dementin, Sébastien; Rousset, Marc; Fontecilla-Camps, Juan C

2015-01-01

Catalytically inactive oxidized O2-sensitive [NiFe]-hydrogenases are characterized by a mixture of the paramagnetic Ni-A and Ni-B states. Upon O2 exposure, enzymes in a partially reduced state preferentially form the unready Ni-A state. Because partial O2 reduction should generate a peroxide intermediate, this species was previously assigned to the elongated Ni-Fe bridging electron density observed for preparations of [NiFe]-hydrogenases known to contain the Ni-A state. However, this proposition has been challenged based on the stability of this state to UV light exposure and the possibility of generating it anaerobically under either chemical or electrochemical oxidizing conditions. Consequently, we have considered alternative structures for the Ni-A species including oxidation of thiolate ligands to either sulfenate or sulfenic acid. Here, we report both new and revised [NiFe]-hydrogenases structures and conclude, taking into account corresponding characterizations by Fourier transform infrared spectroscopy (FTIR), that the Ni-A species contains oxidized cysteine and bridging hydroxide ligands instead of the peroxide ligand we proposed earlier. Our analysis was rendered difficult by the typical formation of mixtures of unready oxidized states that, furthermore, can be reduced by X-ray induced photoelectrons. The present study could be carried out thanks to the use of Desulfovibrio fructosovorans [NiFe]-hydrogenase mutants with special properties. In addition to the Ni-A state, crystallographic results are also reported for two diamagnetic unready states, allowing the proposal of a revised oxidized inactive Ni-SU model and a new structure characterized by a persulfide ion that is assigned to an Ni-'Sox' species.

Prescription drug accessibility and affordability in the United States and abroad.

PubMed

Morgan, Steve; Kennedy, Jae

2010-06-01

This issue brief contrasts prescription drug access, affordability, and costs in the United States with six other high-income countries, drawing from Commonwealth Fund survey data of patient experiences as well as international spending and pricing data. The analysis reveals that Americans, particularly the relatively young and healthy, are more likely to use prescription drugs than are residents of Australia, Canada, Germany, the Netherlands, New Zealand, and the United Kingdom, but they also experience more financial barriers in accessing medications and spend more out-of-pocket for prescriptions. In the U.S., there are also larger income-related inequities in pharmaceutical use. Despite access barriers and disparities, spending per person in the U.S. is far higher, likely the result of paying higher prices for similar medications and using a more expensive mix of drugs. The authors say that value-based benefit designs, reference pricing, and group purchasing could reduce financial barriers and keep down pharmaceutical spending.

The oxidation state of sulfur in apatite: A new oxybarometer?

NASA Astrophysics Data System (ADS)

Fiege, A.; Konecke, B.; Kim, Y.; Simon, A. C.; Becker, U.; Parat, F.

2016-12-01

Oxygen fugacity (fO2) of magmatic and hydrothermal systems influences, for instance, crystallization and degassing processes as well as metal solubilities in melts and fluids. Apatite is a ubiquitous mineral in magmatic and hydrothermal environments that can record and preserve volatile zonation. It can contain several thousand μg/g of the redox sensitive element sulfur (S), making S-in-apatite a potential fO2 sensor. Despite the polyvalent properties of S (e.g., S2-, S4+, S6+), the oxidation state and incorporation mechanisms of S in the apatite structure are poorly understood. In this study, the oxidation state of S-in-apatite as a function of fO2 is investigated using X-ray absorption near-edge structures (XANES) spectroscopy at the S K-edge. Apatites crystallized from lamproitic melts at 1000°C, 300 MPa and over a broad range of fO2 and sulfur fugacities (fS2) were measured. Peaks corresponding to S6+ ( 2482 eV), S4+ ( 2478 eV) and S2- ( 2470 eV) were identified in apatite. The integrated S6+/STotal (STotal = S6+ + S4+ + S2-) peak area ratios show a distinct positive correlation with fO2, increasing from 0.17 at FMQ+0 to 0.96 at FMQ+3. Ab-initio calculations were performed to further understand the energetics and geometry of incorporation of S6+, S4+ and S2- into the apatite (F-, Cl-, OH-) end-members. The results confirm that apatite can contain three different oxidations states of S (S6+, S4+, S2-) as a function of fO2. This makes apatite probably the first geologically relevant mineral to incorporate reduced (S2-), intermediate (S4+), and oxidized (S6+) S in variable proportions. We emphasize that the strong dependence of the S oxidation state in apatite as a function of fO2 is also coupled with changing S content of apatite and co-existing melt (i.e., with changing fS2), resulting in a complex correlation between [1] apatite-melt (or fluid) partitioning, [2] redox conditions and [3] the melt and/or fluid composition, making the application of previously

Beyond Section 508: The Spectrum of Legal Requirements for Accessible e-Government Web Sites in the United States

ERIC Educational Resources Information Center

Jaeger, Paul T.

2004-01-01

In the United States, a number of federal laws establish requirements that electronic government (e-government) information and services be accessible to individuals with disabilities. These laws affect e-government Web sites at the federal, state, and local levels. To this point, research about the accessibility of e-government Web sites has…

Characterization of Intermediate Oxidation States in CO2 Activation

NASA Astrophysics Data System (ADS)

Dodson, Leah G.; Thompson, Michael C.; Weber, J. Mathias

2018-04-01

Redox chemistry during the activation of carbon dioxide involves changing the charge state in a CO2 molecular unit. However, such changes are usually not well described by integer formal charges, and one can think of COO functional units as being in intermediate oxidation states. In this article, we discuss the properties of CO2 and CO2-based functional units in various charge states. Besides covering isolated CO2 and its ions, we describe the CO2-based ionic species formate, oxalate, and carbonate. Finally, we provide an overview of CO2-based functional groups and ligands in clusters and metal-organic complexes.

Considering disparities: How do nurse practitioner regulatory policies, access to care, and health outcomes vary across four states?

PubMed

Sonenberg, Andréa; Knepper, Hillary J

Health disparities persist among morbidity and mortality rates in the United States. Contributing significantly to these disparities are the ability to pay for health care (largely, access to health insurance) and access to, and capacity of, the primary care health workforce. This article examines key determinants of health (DOH) including demographics, public and regulatory policies, health workforce capacity, and primary health outcomes of four states of the United States. The context of this study is the potential association among health care disparities and myriad DOH, among them, the restrictive nurse practitioner (NP) scope of practice (SOP) regulatory environment, which are documented to influence access to care and health outcomes. This descriptive study explores current NP SOP regulations, access to primary care, and health outcomes of key chronic disease indicators-diabetes, hypertension, and obesity in Alabama, Colorado, Mississippi, and Utah. These states represent both the greatest disparity in chronic disease health outcomes (obesity, diabetes, and hypertension) and the greatest difference in modernization of their NP SOP laws. The Affordable Care Act has greatly expanded access to health care. However, it is estimated that 23 million Americans, 7% of its total population, will remain uninsured by 2019. Restrictive and inconsistent NP SOP policies may continue to contribute to health workforce capacity and population health disparities across the country, with particular concern for primary care indicators. The study findings bring into question whether states with more restrictive NP SOP regulations impact access to primary care, which may in turn influence population health outcomes. These findings suggest the need for further research. NPs are essential for meeting the increasing demands of primary care in the United States, and quality-of-care indicator research supports their use. Copyright © 2016 Elsevier Inc. All rights reserved.

Conformational Toggling of Yeast Iso-1-Cytochrome c in the Oxidized and Reduced States

PubMed Central

Yang, Zhongzheng; Zhu, Jing; Ying, Tianlei; Jiang, Xianwang; Zhang, Xu; Wu, Houming; Liu, Maili; Tan, Xiangshi; Cao, Chunyang; Huang, Zhong-Xian

2011-01-01

To convert cyt c into a peroxidase-like metalloenzyme, the P71H mutant was designed to introduce a distal histidine. Unexpectedly, its peroxidase activity was found even lower than that of the native, and that the axial ligation of heme iron was changed to His71/His18 in the oxidized state, while to Met80/His18 in the reduced state, characterized by UV-visible, circular dichroism, and resonance Raman spectroscopy. To further probe the functional importance of Pro71 in oxidation state dependent conformational changes occurred in cyt c, the solution structures of P71H mutant in both oxidation states were determined. The structures indicate that the half molecule of cyt c (aa 50–102) presents a kind of “zigzag riveting ruler” structure, residues at certain positions of this region such as Pro71, Lys73 can move a big distance by altering the tertiary structure while maintaining the secondary structures. This finding provides a molecular insight into conformational toggling in different oxidation states of cyt c that is principle significance to its biological functions in electron transfer and apoptosis. Structural analysis also reveals that Pro71 functions as a key hydrophobic patch in the folding of the polypeptide of the region (aa 50–102), to prevent heme pocket from the solvent. PMID:22087268

Angle-resolved photoemission spectroscopy studies of metallic surface and interface states of oxide insulators

NASA Astrophysics Data System (ADS)

Plumb, Nicholas C.; Radović, Milan

2017-11-01

Over the last decade, conducting states embedded in insulating transition metal oxides (TMOs) have served as gateways to discovering and probing surprising phenomena that can emerge in complex oxides, while also opening opportunities for engineering advanced devices. These states are commonly realized at thin film interfaces, such as the well-known case of LaAlO3 (LAO) grown on SrTiO3 (STO). In recent years, the use of angle-resolved photoemission spectroscopy (ARPES) to investigate the k-space electronic structure of such materials led to the discovery that metallic states can also be formed on the bare surfaces of certain TMOs. In this topical review, we report on recent studies of low-dimensional metallic states confined at insulating oxide surfaces and interfaces as seen from the perspective of ARPES, which provides a direct view of the occupied band structure. While offering a fairly broad survey of progress in the field, we draw particular attention to STO, whose surface is so far the best-studied, and whose electronic structure is probably of the most immediate interest, given the ubiquitous use of STO substrates as the basis for conducting oxide interfaces. The ARPES studies provide crucial insights into the electronic band structure, orbital character, dimensionality/confinement, spin structure, and collective excitations in STO surfaces and related oxide surface/interface systems. The obtained knowledge increases our understanding of these complex materials and gives new perspectives on how to manipulate their properties.

The Effects of State Medicaid Expansion on Low-Income Individuals' Access to Health Care: Multilevel Modeling.

PubMed

Choi, Sunha; Lee, Sungkyu; Matejkowski, Jason

2018-06-01

This study aimed to examine how states' Medicaid expansion affected insurance status and access to health care among low-income expansion state residents in 2015, the second year of the expansion. Data from the 2012 and 2015 Behavioral Risk Factor Surveillance System were linked to state-level data. A nationally representative sample of 544,307 adults (ages 26-64 years) from 50 states and Washington, DC were analyzed using multilevel modeling. The results indicate substantial increases in health care access between 2012 and 2015 among low-income adults in Medicaid expansion states. The final conditional multilevel models with low-income adults who had income at or below 138% of the poverty line indicate that, after controlling for individual- and state-level covariates, those who resided in the Medicaid expansion states were more likely to have health insurance (OR = 1.97, P < .001), have a usual source of care (OR = 1.37, P < .01), and receive a routine checkup (OR = 1.24, P < .01), and were less likely to not see a doctor because of cost (OR = 0.66, P < .001) compared with low-income residents in non-expansion states in 2015. Moreover, the significant interaction terms indicate that adults living in non-expansion states with income below 100% of the poverty line are the most vulnerable compared with their counterparts in expansion states and with those with income between 100%-138% of the poverty line. This study demonstrates that state-level Medicaid expansion improved health care access among low-income US residents. However, residents with income below 100% of the poverty line in non-expansion states were disproportionately negatively affected by states' decision to not expand Medicaid coverage.

Influence of microorganisms on the oxidation state distribution of multivalent actinides under anoxic conditions

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

Reed, Donald Timothy; Borkowski, Marian; Lucchini, Jean - Francois

2010-12-10

The fate and potential mobility of multivalent actinides in the subsurface is receiving increased attention as the DOE looks to cleanup the many legacy nuclear waste sites and associated subsurface contamination. Plutonium, uranium and neptunium are the near-surface multivalent contaminants of concern and are also key contaminants for the deep geologic disposal of nuclear waste. Their mobility is highly dependent on their redox distribution at their contamination source as well as along their potential migration pathways. This redox distribution is often controlled, especially in the near-surface where organic/inorganic contaminants often coexist, by the direct and indirect effects of microbial activity.more » Under anoxic conditions, indirect and direct bioreduction mechanisms exist that promote the prevalence of lower-valent species for multivalent actinides. Oxidation-state-specific biosorption is also an important consideration for long-term migration and can influence oxidation state distribution. Results of ongoing studies to explore and establish the oxidation-state specific interactions of soil bacteria (metal reducers and sulfate reducers) as well as halo-tolerant bacteria and Archaea for uranium, neptunium and plutonium will be presented. Enzymatic reduction is a key process in the bioreduction of plutonium and uranium, but co-enzymatic processes predominate in neptunium systems. Strong sorptive interactions can occur for most actinide oxidation states but are likely a factor in the stabilization of lower-valent species when more than one oxidation state can persist under anaerobic microbiologically-active conditions. These results for microbiologically active systems are interpreted in the context of their overall importance in defining the potential migration of multivalent actinides in the subsurface.« less

Evolution of the Oxidation State of the Earth's Mantle

NASA Technical Reports Server (NTRS)

Danielson, L. R.; Righter, K.; Keller, L.; Christoffersen, E.; Rahman, Z.

2015-01-01

The oxidation state of the Earth's mantle during formation remains an unresolved question, whether it was constant throughout planetary accretion, transitioned from reduced to oxidized, or from oxidized to reduced. We investigate the stability of Fe3(+) at depth, in order to constrain processes (water, late accretion, dissociation of FeO) which may reduce or oxidize the Earth's mantle. In our previous experiments on shergottite compositions, variable fO2, T, and P less than 4 GPa, Fe3(+)/sigma Fe decreased slightly with increasing P, similar to terrestrial basalt. For oxidizing experiments less than 7GPa, Fe3(+)/sigma Fe decreased as well, but it's unclear from previous modelling whether the deeper mantle could retain significant Fe3(+). Our current experiments expand our pressure range deeper into the Earth's mantle and focus on compositions and conditions relevant to the early Earth. Preliminary multi-anvil experiments with Knippa basalt as the starting composition were conducted at 5-7 GPa and 1800 C, using a molybdenum capsule to set the fO2 near IW, by buffering with Mo-MoO3. TEM and EELS analyses revealed the run products quenched to polycrystalline phases, with the major phase pyroxene containing approximately equal to Fe3(+)/2(+). Experiments are underway to produce glassy samples that can be measured by EELS and XANES, and are conducted at higher pressures.

The impact of degassing on the oxidation state of basaltic magmas: A case study of Kīlauea volcano

NASA Astrophysics Data System (ADS)

Moussallam, Yves; Edmonds, Marie; Scaillet, Bruno; Peters, Nial; Gennaro, Emanuela; Sides, Issy; Oppenheimer, Clive

2016-09-01

Volcanic emissions link the oxidation state of the Earth's mantle to the composition of the atmosphere. Whether the oxidation state of an ascending magma follows a redox buffer - hence preserving mantle conditions - or deviates as a consequence of degassing remains under debate. Thus, further progress is required before erupted basalts can be used to infer the redox state of the upper mantle or the composition of their co-emitted gases to the atmosphere. Here we present the results of X-ray absorption near-edge structure (XANES) spectroscopy at the iron K-edge carried out for a series of melt inclusions and matrix glasses from ejecta associated with three eruptions of Kīlauea volcano (Hawai'i). We show that the oxidation state of these melts is strongly correlated with their volatile content, particularly in respect of water and sulfur contents. We argue that sulfur degassing has played a major role in the observed reduction of iron in the melt, while the degassing of H2O and CO2 appears to have had a negligible effect on the melt oxidation state under the conditions investigated. Using gas-melt equilibrium degassing models, we relate the oxidation state of the melt to the composition of the gases emitted at Kīlauea. Our measurements and modelling yield a lower constraint on the oxygen fugacity of the mantle source beneath Kīlauea volcano, which we infer to be near the nickel nickel-oxide (NNO) buffer. Our findings should be widely applicable to other basaltic systems and we predict that the oxidation state of the mantle underneath most hotspot volcanoes is more oxidised than that of the associated lavas. We also suggest that whether the oxidation states of a basalt (in particular MORB) reflects that of its source, is primarily determined by the extent of sulfur degassing.

IDENTIFYING CRITICAL CYSTEINE RESIDUES IN ARSENIC (+3 OXIDATION STATE) METHYLTRANSFERASE

EPA Science Inventory

Arsenic (+3 oxidation state) methyltransferase (AS3MT) catalyzes methylation of inorganic arsenic to mono, di, and trimethylated arsenicals. Orthologous AS3MT genes in genomes ranging from simple echinoderm to human predict a protein with five conserved cysteine (C) residues. In ...

Technical Operating Procedures for State Access Under the Oil Pollution Act of 1990

DOT National Transportation Integrated Search

1992-11-01

Technical Operating Procedures (TOPs) to be used by the National Pollution Funds : Center (NPFC) to provide guidance to Federal On-Scene Coordinators (FOSCs) and : Coast Guard Districts concerning a State Governor's request for access to the : Oil Sp...

Approaches to Determining the Oxidation State of Nitrogen and Carbon Atoms in Organic Compounds for High School Students

ERIC Educational Resources Information Center

Jurowski, Kamil; Krzeczkowska, Malgorzata Krystyna; Jurowska, Anna

2015-01-01

The concept of oxidation state (or oxidation number) and related issues have always been difficult for students. In addition, there are misunderstandings and obscurities, which can cause improper balancing of the chemical equations (mostly in organic reactions). In particular, these problems are related to determination of the oxidation state of…

A Fiscal Analysis of Proposed Education Access Grants in Minneapolis. School Choice Issues in the State

ERIC Educational Resources Information Center

Maas, Ericca

2005-01-01

This study examines the fiscal impact of model legislation that would create Education Access Grants in Minnesota. The legislation would provide grants for low-income students to attend private schools. Specifically, this study examines the effect of implementing Education Access Grants in Minneapolis, the state's largest metropolitan area. It…

The pervasive crisis of diminishing radiation therapy access for vulnerable populations in the United States-part 3: Hispanic-American patients.

PubMed

McClelland, Shearwood; Perez, Carmen A

2018-01-01

Health disparities have profoundly affected underrepresented minorities throughout the United States, particularly with regard to access to evidence-based interventions such as surgery or medication. The degree of disparity in access to radiation therapy (RT) for Hispanic-American patients with cancer has not been previously examined in an extensive manner. An extensive literature search was performed using the PubMed database to examine studies investigating disparities in RT access for Hispanic-Americans. A total of 34 studies were found, spanning 10 organ systems. Disparities in access to RT for Hispanic-Americans were most prominently studied in cancers of the breast (15 studies), prostate (4 studies), head and neck (4 studies), and gynecologic system (3 studies). Disparities in RT access for Hispanic-Americans were prevalent regardless of the organ system studied and were compounded by limited English proficiency and/or birth outside of the United States. A total of 26 of 34 studies (77%) involved analysis of a population-based database, such as Surveillance, Epidemiology and End Result (15 studies); Surveillance, Epidemiology and End Result-Medicare (4 studies); National Cancer Database (3 studies); or a state tumor registry (4 studies). Hispanic-Americans in the United States have diminished RT access compared with Caucasian patients but are less likely to experience concomitant disparities in mortality than other underrepresented minorities that experience similar disparities (ie, African-Americans). Hispanic-Americans who are born outside of the United States and/or have limited English proficiency may be more likely to experience substandard RT access. These results underscore the importance of finding nationwide solutions to address such inequalities that hinder Hispanic-Americans and other underrepresented minorities throughout the United States.

Oxidation-state dependence of rheology in peralkaline glasses of phonolitic composition

NASA Astrophysics Data System (ADS)

Scherrer, M. C.; Hess, K.-U.; Fehr, K. T.; Dingwell, D. B.

2012-04-01

The precise description of magmatic melts rheology at the glass transition is crucial in understanding dynamic processes in volcanology. The glass transition has been described to scale with the viscosity of the material according to Maxwell's relaxation theory for viscoelastic liquids (Dingwell and Webb, 1989). The temperature dependence of the viscosity of multi-component systems can adequately be calculated using empirical models such as Hess et al. (1996), Giordano et al. (2008) and Hui and Zhang (2008); yet, within these calculations, the influence of oxidation state has been so far considered minor and was consequently neglected. The rheological behavior of some iron-rich silicate melts has shown noteworthy oxidation state-dependent variations (Cukierman and Uhlmann 1974, Dingwell and Virgo 1987). The focus of our study is to improve the viscosity models by investigating the necessity of an additional redox-parameter. Thirteen re-melted glass samples of natural phonolitic composition (peralkaline lavas with 8.5 wt. % FeOtot) were produced under different oxygen fugacity (fO2) conditions in a CO/CO2 gas-mixing furnace. Their oxidation-state (Fe3+/Fetot) ranges from 0.44 to 0.93 (±0.05). The viscosity above the liquidus was recorded via the concentric cylinder technique at a constant temperature of 1186 ° C. Additionally, viscosities were measured in the interval of 107to 1011Pa swith temperatures up to 900 ° C at ambient pressure via a BAEHR micro-penetration viscometer. Glass transition temperatures (Tg) have been determined with a constant heating/cooling rate of 10K/min on a SETARAM Sensys evo DSC using the peak of the specific heat capacity curve. Under a constant temperature in the super-liquidus state, the viscosity increases strongly with increasing fO2. In the sub-liquidus state, the measured calorimetric Tgis shifted to lower temperatures as the ratio of ferrous/total iron decreases from 638 ° C to 610 ° C. However, there is no equivalent

Facile solid-state synthesis of oxidation-resistant metal nanoparticles at ambient conditions

NASA Astrophysics Data System (ADS)

Lee, Kyu Hyung; Jung, Hyuk Joon; Lee, Ju Hee; Kim, Kyungtae; Lee, Byeongno; Nam, Dohyun; Kim, Chung Man; Jung, Myung-Hwa; Hur, Nam Hwi

2018-05-01

A simple and scalable method for the synthesis of metal nanoparticles in the solid-state was developed, which can produce nanoparticles in the absence of solvents. Nanoparticles of coinage metals were synthesized by grinding solid hydrazine and the metal precursors in their acetates and oxides at 25 °C. The silver and gold acetates converted completely within 6 min into Ag and Au nanoparticles, respectively, while complete conversion of the copper acetate to the Cu sub-micrometer particles took about 2 h. Metal oxide precursors were also converted into metal nanoparticles by grinding alone. The resulting particles exhibit distinctive crystalline lattice fringes, indicating the formation of highly crystalline phases. The Cu sub-micrometer particles are better resistant to oxidation and exhibit higher conductivity compared to conventional Cu nanoparticles. This solid-state method was also applied for the synthesis of platinum group metals and intermetallic Cu3Au, which can be further extended to synthesize other metal nanoparticles.

State-Targeted Funding and Technical Assistance to Increase Access to Medication Treatment for Opioid Use Disorder.

PubMed

Abraham, Amanda J; Andrews, Christina M; Grogan, Colleen M; Pollack, Harold A; D'Aunno, Thomas; Humphreys, Keith; Friedmann, Peter D

2018-04-01

As the United States grapples with an opioid epidemic, expanding access to effective treatment for opioid use disorder is a major public health priority. Identifying effective policy tools that can be used to expand access to care is critically important. This article examines the relationship between state-targeted funding and technical assistance and adoption of three medications for treating opioid use disorder: oral naltrexone, injectable naltrexone, and buprenorphine. This study draws from the 2013-2014 wave of the National Drug Abuse Treatment System Survey, a nationally representative, longitudinal study of substance use disorder treatment programs. The sample includes data from 695 treatment programs (85.5% response rate) and representatives from single-state agencies in 49 states and Washington, D.C. (98% response rate). Logistic regression was used to examine the relationships of single-state agency targeted funding and technical assistance to availability of opioid use disorder medications among treatment programs. State-targeted funding was associated with increased program-level adoption of oral naltrexone (adjusted odds ratio [AOR]=3.14, 95% confidence interval [CI]=1.49-6.60, p=.004) and buprenorphine (AOR=2.47, 95% CI=1.31-4.67, p=.006). Buprenorphine adoption was also correlated with state technical assistance to support medication provision (AOR=1.18, 95% CI=1.00-1.39, p=.049). State-targeted funding for medications may be a viable policy lever for increasing access to opioid use disorder medications. Given the historically low rates of opioid use disorder medication adoption in treatment programs, single-state agency targeted funding is a potentially important tool to reduce mortality and morbidity associated with opioid disorders and misuse.

Experimental and theoretical identification of the Fe(vii) oxidation state in FeO4.

PubMed

Lu, Jun-Bo; Jian, Jiwen; Huang, Wei; Lin, Hailu; Li, Jun; Zhou, Mingfei

2016-11-16

The experimentally known highest oxidation state of iron has been determined to be Fe(vi) so far. Here we report a combined matrix-isolation infrared spectroscopic and theoretical study of two interconvertible iron oxide anions: a dioxoiron peroxide complex [(η 2 -O 2 )FeO 2 ] - with a C 2v -structure and a tetroxide FeO 4 - with a D 2d tetrahedral structure, which are formed by co-condensation of laser-ablated iron atoms and electrons with O 2 /Ar mixtures at 4 K. Quantum chemistry theoretical studies indicate that the Jahn-Teller distorted tetroxide FeO 4 - anion is a d 1 species with hereto the highest iron formal oxidation state Fe(vii).

Steady-state voltammetry of hydroxide ion oxidation in aqueous solutions containing ammonia.

PubMed

Daniele, Salvatore; Baldo, M Antonietta; Bragato, Carlo; Abdelsalam, Mamdouh Elsayed; Denuault, Guy

2002-07-15

An oxidation process observed in dilute aqueous solutions of ammonia was investigated under steady-state conditions with gold microelectrodes with radii in the range 2.5-30 microm. Over the ammonia concentration range 0.1-10 mM, a well-defined voltammetric wave was observed at approximately 1.4 V versus Ag/AgCl. It was attributed to the oxidation of hydroxide ions that arise from the dissociation of the weak base. The steady-state limiting current was found to depend on the concentration of supporting electrolyte, and in solution with low electrolyte, it was enhanced by migration contribution, as expected for a negatively charged species that oxidizes on a positively charged electrode. In addition, the steady-state limiting current was proportional to both the ammonia concentration and the electrode radius. The overall electrode process was analyzed in terms of a CE mechanism (homogeneous chemical reaction preceding the heterogeneous electron transfer) with a fast chemical reaction when measurements were carried out in solutions containing NH3 at < or = 5 mM and with electrodes having a radius of > or = 5 microm. This was ascertained by comparing experimental and theoretical data obtained by simulation. The formation of the soluble complex species Au(NH3)2+ was also considered as a possible alternative to explain the presence of the oxidation wave. This process however was ruled out, as the experimental data did not fit theoretical predictions in any of the conditions employed in the investigation. Instead, the direct oxidation of NH3, probably to N2O, was invoked to explain the anomalous currents found when the CE process was strongly kinetically hindered. Throughout this study, a parallel was made between the CE mechanism investigated here and that known to occur during the hydrogen evolution reaction from weak acids.

Access to and use of infertility services in the United States: framing the challenges.

PubMed

Adashi, Eli Y; Dean, Laura A

2016-05-01

An overview of access to and use of general infertility and assisted reproductive technology (ART) services in the United States (U.S.) shows a declining trend for the ever-use of infertility services. Moreover, the use of ART services lags relative to other member nations of the Organization for Economic Co-operation and Development (OECD). Access to and use of general infertility and ART services is primarily undermined by a severely constrained underwriting universe dominated by self-insured employers and by a finite number of state infertility insurance mandates. The contribution of traditional public and private payers to the underwriting of ART is limited. As compared with OECD member nations wherein the access to and underwriting of general infertility and ART services is universal, the current status quo in the U.S. can only be characterized as dismal. Further, the current state of affairs is socially unjust in that the right to build a family in the face of infertility appears to have become a function of economic prowess. Given the dominance of the self-insured employers as underwriters of general infertility and ART services, advocacy directed at this interest group is likely to prove most productive. Improving the state of underwriting of general infertility and ART services in the U.S. must be embraced as a central moral imperative and as an unwavering strategic goal of the professional societies entrusted with the reproductive health of women and men. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

An objective alternative to IUPAC's approach to assign oxidation states.

PubMed

Postils, Verònica; Delgado-Alonso, Carlos; Luis, Josep M; Salvador, Pedro

2018-05-22

The IUPAC has recently clarified the term Oxidation State (OS), and provided algorithms for its determination based on the ionic approximation (IA) of the bonds supported by atomic electronegativities (EN). Unfortunately, there are a number of exceptions and ambiguities in IUPAC's algorithms when it comes to practical applications. Our comprehensive study reveals the critical role of the chemical environment on establishing the OS, which cannot always be properly predicted using fix atomic EN values. By identifying what we define here as subsystems of enhanced stability within the molecular system, OS can be safely assigned in many cases without invoking exceptions. New insights about the effect of local aromaticity upon OS are revealed. Moreover, we prove that there are intrinsic limitations of the IA that cannot be overcome. In this context, the effective oxidation state (EOS) analysis arises as a robust and general scheme to derive OS without any external guidance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cellulose accessibility and microbial community in solid state anaerobic digestion of rape straw.

PubMed

Tian, Jiang-Hao; Pourcher, Anne-Marie; Bureau, Chrystelle; Peu, Pascal

2017-01-01

Solid state anaerobic digestion (SSAD) with leachate recirculation is an appropriate method for the valorization of agriculture residues. Rape straw is a massively produced residue with considerable biochemical methane potential, but its degradation in SSAD remains poorly understood. A thorough study was conducted to understand the performance of rape straw as feedstock for laboratory solid state anaerobic digesters. We investigated the methane production kinetics of rape straw in relation to cellulose accessibility to cellulase and the microbial community. Improving cellulose accessibility through milling had a positive influence on both the methane production rate and methane yield. The SSAD of rape straw reached 60% of its BMP in a 40-day pilot-scale test. Distinct bacterial communities were observed in digested rape straw and leachate, with Bacteroidales and Sphingobacteriales as the most abundant orders, respectively. Archaeal populations showed no phase preference and increased chronologically. Copyright © 2016 Elsevier Ltd. All rights reserved.

Trends in Perceived Access to Marijuana Among Adolescents in the United States: 2002-2015.

PubMed

Salas-Wright, Christopher P; Oh, Sehun; Goings, Trenette Clark; Vaughn, Michael G

2017-09-01

There is concern that changes in marijuana-related policy and public opinion may lead to increased access to marijuana among young people in the United States. However, little research has been conducted on changes in youth's perceptions of marijuana access, and studies have yet to systematically examine trends in perceived access across key sociodemographic and externalizing behavioral subgroups. Using population-based data collected between 2002 and 2015 as part of the National Survey on Drug Use and Health, we examined trends in perceived marijuana access among non-Hispanic White, African American, and Hispanic adolescents (ages 12-17, n = 221,412). Following the trend analysis method outlined by the Centers for Disease Control and Prevention, we conducted logistic regression analyses to test for secular trends. Between 2002 and 2015, we observed a 27% overall reduction in the relative proportion of adolescents ages 12-17-and a 42% reduction among those ages 12-14-reporting that it would be "very easy" to obtain marijuana. This pattern was uniformly observed among youth in all sociodemographic subgroups (i.e., across age, gender, race/ethnicity, household income) and among youth reporting involvement/no involvement in most measures of substance use (alcohol, marijuana) and delinquency (handgun carrying, attacks). However, perceived very easy access remained stable among youth reporting tobacco use and criminal justice system involvement. Despite the legalization of recreational and medical marijuana in some states, our findings suggest that, with the notable exception of adolescent tobacco users and juvenile offenders, perceptions that marijuana would be very easy to obtain are on the decline among American youth.

Effect of expansions in state Medicaid eligibility on access to care and the use of emergency department services for adult Medicaid enrollees.

PubMed

Ndumele, Chima D; Mor, Vincent; Allen, Susan; Burgess, James F; Trivedi, Amal N

2014-06-01

Medicaid enrollees typically report worse access to care than other insured populations. Expansions in Medicaid through less restrictive income eligibility requirements and the resulting influx of new enrollees may further erode access to care for those already enrolled in Medicaid. To assess the effect of previous Medicaid expansions on self-reported access to care and the use of emergency department services by Medicaid enrollees. Quasi-experimental difference-in-differences design among 1714 adult Medicaid enrollees in 10 states that expanded Medicaid between June 1, 2000, and October 1, 2009, and 5097 Medicaid enrollees in 14 bordering control states that did not expand Medicaid. Self-reported access to care and annualized emergency department use. Among states expanding their Medicaid program for adults, the mean income eligibility level increased from 82.6% to 144.2% of the federal poverty level. Income eligibility in matched control states remained constant at 77.1% of the federal poverty level. The proportion of adults reporting being enrolled in Medicaid increased from 7.2% to 8.8% in expansion states and from 6.1% to 6.4% in matched control states. In Medicaid program expansion states, the proportion of Medicaid enrollees reporting poor access to care declined from 8.5% before the expansion to 7.3% after the expansion. In matched control states, the proportion of Medicaid enrollees reporting poor access to care remained constant at 5.3%. The proportion of enrollees reporting any emergency department use decreased from 41.2% to 40.1% in expansion states and from 37.3% to 36.1% in matched control states. In the period following expansions, newly eligible enrollees reported poorer access to care than previously enrolled beneficiaries, although the overall difference between groups did not reach statistical significance. We found no evidence that expanding the number of individuals eligible for Medicaid coverage eroded perceived access to care or increased

DetOx: a program for determining anomalous scattering factors of mixed-oxidation-state species.

PubMed

Sutton, Karim J; Barnett, Sarah A; Christensen, Kirsten E; Nowell, Harriott; Thompson, Amber L; Allan, David R; Cooper, Richard I

2013-01-01

Overlapping absorption edges will occur when an element is present in multiple oxidation states within a material. DetOx is a program for partitioning overlapping X-ray absorption spectra into contributions from individual atomic species and computing the dependence of the anomalous scattering factors on X-ray energy. It is demonstrated how these results can be used in combination with X-ray diffraction data to determine the oxidation state of ions at specific sites in a mixed-valance material, GaCl(2).

The Role of Seven-Coordination in Ru-Catalyzed Water Oxidation

DOE PAGES

Matheu, Roc; Ertem, Mehmed Z.; Pipelier, Muriel; ...

2018-01-19

A family of Ru complexes based on the pentadentate ligand t5a 3– ((2,5-bis(6-carboxylatopyridin-2-yl)pyrrol-1-ide) and pyridine (py) that includes {Ru II(Ht5a-κ-N 2O)(py) 3} (1H II(κ-N 2O)), {Ru III(t5a-κ-N 3O 1.5)(py) 2} (2 III(κ-N 3O 1.5)), and {Ru IV(t5a-κ-N 3O 2)(py) 2}+ ({2 IV(κ-N3O 2)}+) has been prepared and thoroughly characterized. Complexes 1HII(κ-N 2O), 2 III(κ-N 3O 1.5), and {2 IV(κ-N 3O 2)}+ have been investigated in solution by spectroscopic methods (NMR, UV–vis) and in the solid state by single-crystal X-ray diffraction analysis and complemented by density functional theory (DFT) calculations. The redox properties of complex 2 III(κ-N 3O 1.5) have beenmore » studied by electrochemical methods (CV and DPV), showing its easy access to high oxidation states, thanks to the trianionic nature of the t5a 3– ligand. Under neutral to basic conditions complex {2 IV(κ-N3O 2)}+ undergoes aquation, generating {Ru IV(OH)(t5a-κ-N 2O)(py) 2} (2 IV(OH)(κ-N 2O)). Further oxidation of the complex forms {Ru V(O)(t5a-κ-N 2O)(py) 2} (2 V(O)(κ-N 2O)), which is a very efficient water oxidation catalyst, reaching a TOF MAX value of 9400 s –1 at pH 7.0, as measured via foot of the wave analysis. The key to fast kinetics for the catalytic oxidation of water to dioxygen by 2 V(O)(κ-N 2O) is due not only to the easy access to high oxidation states but also to the intramolecular hydrogen bonding provided by the noncoordinated dangling carboxylate at the transition state, as corroborated by DFT calculations.« less

The Role of Seven-Coordination in Ru-Catalyzed Water Oxidation

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

Matheu, Roc; Ertem, Mehmed Z.; Pipelier, Muriel

A family of Ru complexes based on the pentadentate ligand t5a 3– ((2,5-bis(6-carboxylatopyridin-2-yl)pyrrol-1-ide) and pyridine (py) that includes {Ru II(Ht5a-κ-N 2O)(py) 3} (1H II(κ-N 2O)), {Ru III(t5a-κ-N 3O 1.5)(py) 2} (2 III(κ-N 3O 1.5)), and {Ru IV(t5a-κ-N 3O 2)(py) 2}+ ({2 IV(κ-N3O 2)}+) has been prepared and thoroughly characterized. Complexes 1HII(κ-N 2O), 2 III(κ-N 3O 1.5), and {2 IV(κ-N 3O 2)}+ have been investigated in solution by spectroscopic methods (NMR, UV–vis) and in the solid state by single-crystal X-ray diffraction analysis and complemented by density functional theory (DFT) calculations. The redox properties of complex 2 III(κ-N 3O 1.5) have beenmore » studied by electrochemical methods (CV and DPV), showing its easy access to high oxidation states, thanks to the trianionic nature of the t5a 3– ligand. Under neutral to basic conditions complex {2 IV(κ-N3O 2)}+ undergoes aquation, generating {Ru IV(OH)(t5a-κ-N 2O)(py) 2} (2 IV(OH)(κ-N 2O)). Further oxidation of the complex forms {Ru V(O)(t5a-κ-N 2O)(py) 2} (2 V(O)(κ-N 2O)), which is a very efficient water oxidation catalyst, reaching a TOF MAX value of 9400 s –1 at pH 7.0, as measured via foot of the wave analysis. The key to fast kinetics for the catalytic oxidation of water to dioxygen by 2 V(O)(κ-N 2O) is due not only to the easy access to high oxidation states but also to the intramolecular hydrogen bonding provided by the noncoordinated dangling carboxylate at the transition state, as corroborated by DFT calculations.« less

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2014 CFR

2014-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2011 CFR

2011-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2010 CFR

2010-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2013 CFR

2013-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2012 CFR

2012-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

Disparities in Geographic Accessibility of National Cancer Institute Cancer Centers in the United States.

PubMed

Xu, Yanqing; Fu, Cong; Onega, Tracy; Shi, Xun; Wang, Fahui

2017-11-11

The National Cancer Institute (NCI) Cancer Centers form the backbone of the cancer care system in the United States since their inception in the early 1970s. Most studies on their geographic accessibility used primitive measures, and did not examine the disparities across urbanicity or demographic groups. This research uses an advanced accessibility method, termed "2-step floating catchment area (2SFCA)" and implemented in Geographic Information Systems (GIS), to capture the degree of geographic access to NCI Cancer Centers by accounting for competition intensity for the services and travel time between residents and the facilities. The results indicate that urban advantage is pronounced as the average accessibility is highest in large central metro areas, declines to large fringe metro, medium metro, small metro, micropolitan and noncore rural areas. Population under the poverty line are disproportionally concentrated in lower accessibility areas. However, on average Non-Hispanic White have the lowest geographic accessibility, followed by Hispanic, Non-Hispanic Black and Asian, and the differences are statistically significant. The "reversed racial disadvantage" in NCI Cancer Center accessibility seems counterintuitive but is consistent with an influential prior study; and it is in contrast to the common observation of co-location of concentration of minority groups and people under the poverty line.

Mapping integration of midwives across the United States: Impact on access, equity, and outcomes

PubMed Central

Stoll, Kathrin; MacDorman, Marian; Declercq, Eugene; Cramer, Renee; Cheyney, Melissa; Fisher, Timothy; Butt, Emma; Yang, Y. Tony; Powell Kennedy, Holly

2018-01-01

Poor coordination of care across providers and birth settings has been associated with adverse maternal-newborn outcomes. Research suggests that integration of midwives into regional health systems is a key determinant of optimal maternal-newborn outcomes, yet, to date, the characteristics of an integrated system have not been described, nor linked to health disparities. Methods Our multidisciplinary team examined published regulatory data to inform a 50-state database describing the environment for midwifery practice and interprofessional collaboration. Items (110) detailed differences across jurisdictions in scope of practice, autonomy, governance, and prescriptive authority; as well as restrictions that can affect patient safety, quality, and access to maternity providers across birth settings. A nationwide survey of state regulatory experts (n = 92) verified the ‘on the ground’ relevance, importance, and realities of local interpretation of these state laws. Using a modified Delphi process, we selected 50/110 key items to include in a weighted, composite Midwifery Integration Scoring (MISS) system. Higher scores indicate greater integration of midwives across all settings. We ranked states by MISS scores; and, using reliable indicators in the CDC-Vital Statistics Database, we calculated correlation coefficients between MISS scores and maternal-newborn outcomes by state, as well as state density of midwives and place of birth. We conducted hierarchical linear regression analysis to control for confounding effects of race. Results MISS scores ranged from lowest at 17 (North Carolina) to highest at 61 (Washington), out of 100 points. Higher MISS scores were associated with significantly higher rates of spontaneous vaginal delivery, vaginal birth after cesarean, and breastfeeding, and significantly lower rates of cesarean, preterm birth, low birth weight infants, and neonatal death. MISS scores also correlated with density of midwives and access to care across

State Public Policies and the Racial/Ethnic Stratification of College Access and Choice in the State of Maryland

ERIC Educational Resources Information Center

Perna, Laura W.; Steele, Patricia; Woda, Susan; Hibbert, Taifa

2005-01-01

This study uses descriptive analyses of data from multiple sources to examine changes during the 1990s in the racial/ethnic stratification of college access and choice in Maryland and to explore state public policies that may have influenced changes in the demand for and supply of higher education for students of different racial/ethnic groups…

Where is the state? How is the state? Accessing water and the state in Mumbai and Johannesburg.

PubMed

Bawa, Zainab

2011-01-01

This article examines the water distribution systems in Johannesburg and Mumbai to argue that the political and institutional contexts of service delivery shape people’s access to the state and its resources, and also mediation between citizens and government institutions by councillors. Through ethnographies of water supply and distribution systems in Mumbai and Johannesburg, I explain how the organizational structure of the water utility, institutional arrangements of service delivery, regulatory systems, councillors’ proximity to decision makers and their relationship with municipal officials, civil servants and party members variously influence councillors’ mediation capacities and their ability to fulfil the claims of their constituencies for piped water supply and connections.

Direct access: factors that affect physical therapist practice in the state of Ohio.

PubMed

McCallum, Christine A; DiAngelis, Tom

2012-05-01

Direct access to physical therapist services is permitted by law in the majority of states and across all practice settings. Ohio enacted such legislation in 2004; however, it was unknown how direct access had affected actual clinical practice. The purpose of this study was to describe physical therapist and physical therapist practice environment factors that affect direct access practice. A 2-phase, mixed-method descriptive study was conducted. In the first phase, focus group interviews with 32 purposively selected physical therapists were completed, which resulted in 8 themes for an electronically distributed questionnaire. In the second phase, survey questionnaires were distributed to physical therapists with an e-mail address on file with the Ohio licensing board. An adjusted return rate of 23% was achieved. Data were analyzed for descriptive statistics. A constant comparative method assessed open-ended questions for common themes and patterns. Thirty-one percent of the respondents reported using direct access in physical therapist practice; however, 80% reported they would practice direct access if provided the opportunity. Physical therapists who practiced direct access were more likely to be in practice 6 years or more and hold advanced degrees beyond the entry level, were American Physical Therapy Association members, and had supportive management and organizational practice policies. The direct access physical therapist practice was generally a locally owned suburban private practice or a school-based clinic that saw approximately 6% to 10% of its patients by direct access. The majority of patients treated were adults with musculoskeletal or neuromuscular impairments. Nonresponse from e-mail may be associated with sample frame bias. Implementation of a direct access physical therapist practice model is evident in Ohio. Factors related to reimbursement and organizational policy appear to impede the process.

Rapid assessment of oxidation via middle-down LCMS correlates with methionine side-chain solvent-accessible surface area for 121 clinical stage monoclonal antibodies.

PubMed

Yang, Rong; Jain, Tushar; Lynaugh, Heather; Nobrega, R Paul; Lu, Xiaojun; Boland, Todd; Burnina, Irina; Sun, Tingwan; Caffry, Isabelle; Brown, Michael; Zhi, Xiaoyong; Lilov, Asparouh; Xu, Yingda

Susceptibility of methionine to oxidation is an important concern for chemical stability during the development of a monoclonal antibody (mAb) therapeutic. To minimize downstream risks, leading candidates are usually screened under forced oxidation conditions to identify oxidation-labile molecules. Here we report results of forced oxidation on a large set of in-house expressed and purified mAbs with variable region sequences corresponding to 121 clinical stage mAbs. These mAb samples were treated with 0.1% H 2 O 2 for 24 hours before enzymatic cleavage below the hinge, followed by reduction of inter-chain disulfide bonds for the detection of the light chain, Fab portion of heavy chain (Fd) and Fc by liquid chromatography-mass spectrometry. This high-throughput, middle-down approach allows detection of oxidation site(s) at the resolution of 3 distinct segments. The experimental oxidation data correlates well with theoretical predictions based on the solvent-accessible surface area of the methionine side-chains within these segments. These results validate the use of upstream computational modeling to predict mAb oxidation susceptibility at the sequence level.

Solid-State Diffusional Behaviors of Functional Metal Oxides at Atomic Scale.

PubMed

Chen, Jui-Yuan; Huang, Chun-Wei; Wu, Wen-Wei

2018-02-01

Metal/metal oxides have attracted extensive research interest because of their combination of functional properties and compatibility with industry. Diffusion and thermal reliability have become essential issues that require detailed study to develop atomic-scaled functional devices. In this work, the diffusional reaction behavior that transforms piezoelectric ZnO into magnetic Fe 3 O 4 is investigated at the atomic scale. The growth kinetics of metal oxides are systematically studied through macro- and microanalyses. The growth rates are evaluated by morphology changes, which determine whether the growth behavior was a diffusion- or reaction-controlled process. Furthermore, atom attachment on the kink step is observed at the atomic scale, which has important implications for the thermodynamics of functional metal oxides. Faster growth planes simultaneously decrease, which result in the predominance of low surface energy planes. These results directly reveal the atomic formation process of metal oxide via solid-state diffusion. In addition, the nanofabricated method provides a novel approach to investigate metal oxide evolution and sheds light on diffusional reaction behavior. More importantly, the results and phenomena of this study provide considerable inspiration to enhance the material stability and reliability of metal/oxide-based devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal oxide resistive random access memory based synaptic devices for brain-inspired computing

NASA Astrophysics Data System (ADS)

Gao, Bin; Kang, Jinfeng; Zhou, Zheng; Chen, Zhe; Huang, Peng; Liu, Lifeng; Liu, Xiaoyan

2016-04-01

The traditional Boolean computing paradigm based on the von Neumann architecture is facing great challenges for future information technology applications such as big data, the Internet of Things (IoT), and wearable devices, due to the limited processing capability issues such as binary data storage and computing, non-parallel data processing, and the buses requirement between memory units and logic units. The brain-inspired neuromorphic computing paradigm is believed to be one of the promising solutions for realizing more complex functions with a lower cost. To perform such brain-inspired computing with a low cost and low power consumption, novel devices for use as electronic synapses are needed. Metal oxide resistive random access memory (ReRAM) devices have emerged as the leading candidate for electronic synapses. This paper comprehensively addresses the recent work on the design and optimization of metal oxide ReRAM-based synaptic devices. A performance enhancement methodology and optimized operation scheme to achieve analog resistive switching and low-energy training behavior are provided. A three-dimensional vertical synapse network architecture is proposed for high-density integration and low-cost fabrication. The impacts of the ReRAM synaptic device features on the performances of neuromorphic systems are also discussed on the basis of a constructed neuromorphic visual system with a pattern recognition function. Possible solutions to achieve the high recognition accuracy and efficiency of neuromorphic systems are presented.

Perceived impact and feasibility of strategies to improve access to healthy foods in Washington State, USA.

PubMed

Johnson, Donna B; Quinn, Emilee L; Podrabsky, Mary; Beckwith-Stanley, Nadia; Chan, Nadine; Ellings, Amy; Kovacs, Tricia; Lane, Claire

2013-12-01

The present study measured the perceived impact and political and implementation feasibility of state-level policy strategies related to increasing access to healthy foods and limiting unhealthy foods. Potential state-level policy strategies to improve access to healthy foods were identified through a review of evidence-based literature and policy recommendations. Respondents rated the perceived impact and political and implementation feasibility of each policy on a five-point scale using online surveys. Washington State policy process. Forty-nine content experts (national researchers and subject experts), forty policy experts (state elected officials or their staff, gubernatorial or legislative policy analysts) and forty-five other stakeholders (state-level advocates, programme administrators, food producers). In aggregate, respondents rated policy impact and implementation feasibility higher than political feasibility. Policy experts rated policy strategies as less politically feasible compared with content experts (P < 0·02) or other stakeholders (P < 0·001). Eight policy strategies were rated above the median for impact and political and implementation feasibility. These included policies related to nutrition standards in schools and child-care facilities, food distribution systems, urban planning projects, water availability, joint use agreements and breast-feeding supports. Although they may be perceived as potentially impactful, some policies will be more difficult to enact than others. Information about the potential feasibility of policies to improve access to healthy foods can be used to focus limited policy process resources on strategies with the highest potential for enactment, implementation and impact.

Structural differences between the ready and unready oxidized states of [NiFe] hydrogenases.

PubMed

Volbeda, Anne; Martin, Lydie; Cavazza, Christine; Matho, Michaël; Faber, Bart W; Roseboom, Winfried; Albracht, Simon P J; Garcin, Elsa; Rousset, Marc; Fontecilla-Camps, Juan C

2005-05-01

[NiFe] hydrogenases catalyze the reversible heterolytic cleavage of molecular hydrogen. Several oxidized, inactive states of these enzymes are known that are distinguishable by their very different activation properties. So far, the structural basis for this difference has not been understood because of lack of relevant crystallographic data. Here, we present the crystal structure of the ready Ni-B state of Desulfovibrio fructosovorans [NiFe] hydrogenase and show it to have a putative mu-hydroxo Ni-Fe bridging ligand at the active site. On the other hand, a new, improved refinement procedure of the X-ray diffraction data obtained for putative unready Ni-A/Ni-SU states resulted in a more elongated electron density for the bridging ligand, suggesting that it is a diatomic species. The slow activation of the Ni-A state, compared with the rapid activation of the Ni-B state, is therefore proposed to result from the different chemical nature of the ligands in the two oxidized species. Our results along with very recent electrochemical studies suggest that the diatomic ligand could be hydro-peroxide.

Forcing Cesium into Higher Oxidation States Using Useful hard x-ray Induced Chemistry under High Pressure

NASA Astrophysics Data System (ADS)

Sneed, D.; Pravica, M.; Kim, E.; Chen, N.; Park, C.; White, M.

2017-10-01

This paper discusses our attempt to synthesize higher oxidation forms of cesium fluoride by pressurizing cesium fluoride in a fluorine-rich environment created via the x-ray decomposition of potassium tetrafluoroborate. This was done in order to confirm recent theoretical predictions of higher oxidation forms of CsFn. We discuss the development of a technique to produce molecular fluorine in situ via useful hard x-ray photochemistry, and the attempt to utilize this technique to form higher oxidation states of cesium fluoride. In order to verify the formation of the novel stoichiometric species of CsFn. X-ray Absorption Near Edge Spectroscopy (XANES) centered on the cesium K-edge was performed to probe the oxidation state of cesium as well as the local molecular coordination around Cs.

Impact of the cation distribution homogeneity on the americium oxidation state in the U0.54Pu0.45Am0.01O2-x mixed oxide

NASA Astrophysics Data System (ADS)

Vauchy, Romain; Robisson, Anne-Charlotte; Martin, Philippe M.; Belin, Renaud C.; Aufore, Laurence; Scheinost, Andreas C.; Hodaj, Fiqiri

2015-01-01

The impact of the cation distribution homogeneity of the U0.54Pu0.45Am0.01O2-x mixed oxide on the americium oxidation state was studied by coupling X-ray diffraction (XRD), electron probe micro analysis (EPMA) and X-ray absorption spectroscopy (XAS). Oxygen-hypostoichiometric Am-bearing uranium-plutonium mixed oxide pellets were fabricated by two different co-milling based processes in order to obtain different cation distribution homogeneities. The americium was generated from β- decay of 241Pu. The XRD analysis of the obtained compounds did not reveal any structural difference between the samples. EPMA, however, revealed a high homogeneity in the cation distribution for one sample, and substantial heterogeneity of the U-Pu (so Am) distribution for the other. The difference in cation distribution was linked to a difference in Am chemistry as investigated by XAS, with Am being present at mixed +III/+IV oxidation state in the heterogeneous compound, whereas only Am(IV) was observed in the homogeneous compound. Previously reported discrepancies on Am oxidation states can hence be explained by cation distribution homogeneity effects.

The joint effects of census tract poverty and geographic access on late-stage breast cancer diagnosis in 10 US States.

PubMed

Henry, Kevin A; Sherman, Recinda; Farber, Steve; Cockburn, Myles; Goldberg, Daniel W; Stroup, Antoinette M

2013-05-01

This study evaluated independent and joint effects of census tract (CT) poverty and geographic access to mammography on stage at diagnosis for breast cancer. The study included 161,619 women 40+ years old diagnosed with breast cancer between 2004 -2006 in ten participating US states. Multilevel logistic regression was used to estimate the odds of late-stage breast cancer diagnosis for the entire study population and by state. Poverty was independently associated with late-stage in the overall population (poverty rates >20% OR=1.30, 95% CI=1.26- 1.35) and for 9 of the 10 states. Geographic access was not associated with late-stage diagnosis after adjusting for CT poverty. State-specific analysis provided little evidence that geographic access was associated with breast cancer stage at diagnosis, and after adjusting for poverty, geographic access mattered in only 1 state. Overall, compared to women with private insurance, the adjusted odds ratios for late stage at diagnosis among women with either no insurance, Medicaid, or Medicare were 1.80 (95% CI = 1.65, 1.96), 1.75 (95% CI = 1.68, 1.84), and 1.05 (95% CI 1.01, 1.08), respectively. Although geographic access to mammography was not a significant predictor of late-stage breast cancer diagnosis, women in high poverty areas or uninsured are at greatest risk of being diagnosed with late-stage breast cancer regardless of geographic location and may benefit from targeted interventions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Forcing Cesium into Higher Oxidation States Using Useful hard x-ray Induced Chemistry under High Pressure

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

Sneed, D.; Pravica, M.; Kim, E.

This paper discusses our attempt to synthesize higher oxidation forms of cesium fluoride by pressurizing cesium fluoride in a fluorine-rich environment created via the x-ray decomposition of potassium tetrafluoroborate. This was done in order to confirm recent theoretical predictions of higher oxidation forms of CsFn. We discuss the development of a technique to produce molecular fluorine in situ via useful hard x-ray photochemistry, and the attempt to utilize this technique to form higher oxidation states of cesium fluoride. In order to verify the formation of the novel stoichiometric species of CsFn. X-ray Absorption Near Edge Spectroscopy (XANES) centered on themore » cesium K-edge was performed to probe the oxidation state of cesium as well as the local molecular coordination around Cs.« less

Improving access of associated states to advanced concepts in medical telematics--a day before the accession to EU.

PubMed

Duplaga, Mariusz; Leszczuk, Mikolaj; Zielinski, Krzysztof

2006-01-01

Central and Eastern Europe countries (CEEC) undertook considerable efforts to include themselves in the main research and development activities in the area of health telematics in Europe. Countries of this region demonstrate diversified environments of economy transformation and health care systems status. The transition phase to market economy brings essential risks to the healthcare system performance. It seems that efforts of developing e-health environment in CEEC could be substantially accelerated by extended co-operation with partners from current member states of the European Union. The PRO-ACCESS project was initiated in the late phase of fifth Framework Programme as supporting action. It focused on the transfer of current concepts in medical telematics to countries remaining in the pre-accession phase. The process of dissemination of up-to-date approaches to e-health environment development is carried out by the Krakow Centre of Telemedicine and is supported by leading health telematics centres in Europe. To accelerate the dissemination activities the network of co-operating centres in CEEC was established. The strategy employed within the PRO-ACCESS project is supposed to yield "critical mass" necessary for facilitating the e-health development in this region of Europe. The activities employed to reach this objective included publishing activities, events and trainings as well as intake of solutions from supporting centres.

State Challenges to "Plyler v. Doe": Undocumented Immigrant Students and Public School Access

ERIC Educational Resources Information Center

Sutton, Lenford C.; Stewart, Tricia J.

2013-01-01

This article presents a review and analysis of selected state laws and initiatives that have attempted to restrict public school access for undocumented immigrant children in the wake of the landmark U.S. Supreme Court decision of "Plyler v. Doe." Sutton and Stewart begin with an overview of the Court's ruling in "Plyler," then…

Revealing the role of oxidation state in interaction between nitro/amino-derived particulate matter and blood proteins

PubMed Central

Liu, Zhen; Li, Ping; Bian, Weiwei; Yu, Jingkai; Zhan, Jinhua

2016-01-01

Surface oxidation states of ultrafine particulate matter can influence the proinflammatory responses and reactive oxygen species levels in tissue. Surface active species of vehicle-emission soot can serve as electron transfer-mediators in mitochondrion. Revealing the role of surface oxidation state in particles-proteins interaction will promote the understanding on metabolism and toxicity. Here, the surface oxidation state was modeled by nitro/amino ligands on nanoparticles, the interaction with blood proteins were evaluated by capillary electrophoresis quantitatively. The nitro shown larger affinity than amino. On the other hand, the affinity to hemoglobin is 103 times larger than that to BSA. Further, molecular docking indicated the difference of binding intensity were mainly determined by hydrophobic forces and hydrogen bonds. These will deepen the quantitative understanding of protein-nanoparticles interaction from the perspective of surface chemical state. PMID:27181651

Spectroscopic characterization of zinc oxide nanorods synthesized by solid-state reaction

NASA Astrophysics Data System (ADS)

Prasad, Virendra; D'Souza, Charlene; Yadav, Deepti; Shaikh, A. J.; Vigneshwaran, Nadanathangam

2006-09-01

Well-crystallized zinc oxide nanorods have been fabricated by single step solid-state reaction using zinc acetate and sodium hydroxide, at room temperature. The sodium lauryl sulfate (SLS) stabilized zinc oxide nanorods were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectroscopy. The X-ray diffraction revealed the wurtzite structure of zinc oxide. The size estimation by XRD and TEM confirmed that the ZnO nanorods are made of single crystals. The growth of zinc oxide crystals into rod shape was found to be closely related to its hexagonal nature. The mass ratio of SLS:ZnO in the nanorods was found to be 1:10 based on the thermogravimetric analysis. Blue shift of photoluminescence emission was noticed in the ZnO nanorods when compared to that of ZnO bulk. FT-IR analysis confirmed the binding of SLS with ZnO nanorods. Apart from ease of preparation, this method has the advantage of eco-friendliness since the solvent and other harmful chemicals were eliminated in the synthesis protocol.

The Impact of Environmental Factors in Influencing Epigenetics Related to Oxidative States in the Cardiovascular System.

PubMed

Angelini, Francesco; Pagano, Francesca; Bordin, Antonella; Milan, Marika; Chimenti, Isotta; Peruzzi, Mariangela; Valenti, Valentina; Marullo, Antonino; Schirone, Leonardo; Palmerio, Silvia; Sciarretta, Sebastiano; Murdoch, Colin E; Frati, Giacomo; De Falco, Elena

2017-01-01

Oxidative states exert a significant influence on a wide range of biological and molecular processes and functions. When their balance is shifted towards enhanced amounts of free radicals, pathological phenomena can occur, as the generation of reactive oxygen species (ROS) in tissue microenvironment or in the systemic circulation can be detrimental. Epidemic chronic diseases of western societies, such as cardiovascular disease, obesity, and diabetes correlate with the imbalance of redox homeostasis. Current advances in our understanding of epigenetics have revealed a parallel scenario showing the influence of oxidative stress as a major regulator of epigenetic gene regulation via modification of DNA methylation, histones, and microRNAs. This has provided both the biological link and a potential molecular explanation between oxidative stress and cardiovascular/metabolic phenomena. Accordingly, in this review, we will provide current insights on the physiological and pathological impact of changes in oxidative states on cardiovascular disorders, by specifically focusing on the influence of epigenetic regulation. A special emphasis will highlight the effect on epigenetic regulation of human's current life habits, external and environmental factors, including food intake, tobacco, air pollution, and antioxidant-based approaches. Additionally, the strategy to quantify oxidative states in humans in order to determine which biological marker could best match a subject's profile will be discussed.

The Impact of Environmental Factors in Influencing Epigenetics Related to Oxidative States in the Cardiovascular System

PubMed Central

Angelini, Francesco; Pagano, Francesca; Bordin, Antonella; Milan, Marika; Valenti, Valentina; Marullo, Antonino; Schirone, Leonardo; Palmerio, Silvia; Sciarretta, Sebastiano; Frati, Giacomo

2017-01-01

Oxidative states exert a significant influence on a wide range of biological and molecular processes and functions. When their balance is shifted towards enhanced amounts of free radicals, pathological phenomena can occur, as the generation of reactive oxygen species (ROS) in tissue microenvironment or in the systemic circulation can be detrimental. Epidemic chronic diseases of western societies, such as cardiovascular disease, obesity, and diabetes correlate with the imbalance of redox homeostasis. Current advances in our understanding of epigenetics have revealed a parallel scenario showing the influence of oxidative stress as a major regulator of epigenetic gene regulation via modification of DNA methylation, histones, and microRNAs. This has provided both the biological link and a potential molecular explanation between oxidative stress and cardiovascular/metabolic phenomena. Accordingly, in this review, we will provide current insights on the physiological and pathological impact of changes in oxidative states on cardiovascular disorders, by specifically focusing on the influence of epigenetic regulation. A special emphasis will highlight the effect on epigenetic regulation of human's current life habits, external and environmental factors, including food intake, tobacco, air pollution, and antioxidant-based approaches. Additionally, the strategy to quantify oxidative states in humans in order to determine which biological marker could best match a subject's profile will be discussed. PMID:28607629

On the link between hygroscopicity, volatility, and oxidation state of ambient and water-soluble aerosol in the Southeastern United States

NASA Astrophysics Data System (ADS)

Cerully, K. M.; Bougiatioti, A.; Hite, J. R., Jr.; Guo, H.; Xu, L.; Ng, N. L.; Weber, R.; Nenes, A.

2014-12-01

The formation of secondary organic aerosol (SOA) combined with the partitioning of semi-volatile organic components can impact numerous aerosol properties including cloud condensation nuclei (CCN) activity, hygroscopicity and volatility. During the summer 2013 Southern Oxidant and Aerosol Study (SOAS) field campaign in a rural site in the Southeastern United States, a suite of instruments including a CCN counter, a thermodenuder (TD) and a high resolution time-of-flight aerosol mass spectrometer (AMS) were used to measure CCN activity, aerosol volatility, composition and oxidation state. Particles were either sampled directly from ambient or through a Particle Into Liquid Sampler (PILS), allowing the investigation of the water-soluble aerosol component. Ambient aerosol exhibited size-dependent composition with larger particles being more hygroscopic. The hygroscopicity of thermally-denuded aerosol was similar between ambient and PILS-generated aerosol and showed limited dependence on volatilization. Results of AMS 3-factor Positive Matrix Factorization (PMF) analysis for the PILS-generated aerosol showed that the most hygroscopic components are most likely the most and the least volatile features of the aerosol. No clear relationship was found between organic hygroscopicity and oxygen-to-carbon ratio; in fact, Isoprene organic aerosol (Isoprene-OA) was found to be the most hygroscopic factor, while at the same time being the least oxidized and likely most volatile of all PMF factors. Considering the diurnal variation of each PMF factor and its associated hygroscopicity, Isoprene-OA and More Oxidized - Oxidized Oxygenated Organic Aerosol (MO-OOA) are the prime contributors to hygroscopicity and covary with Less Oxidized - Oxidized Oxygenated Organic Aerosol (LO-OOA) in a way that induces the observed diurnal invariance in total organic hygroscopicity. Biomass Burning Organic Aerosol (BBOA) contributed little to aerosol hygroscopicity, which is expected since there

Microbial utilization of low molecular weight organic substrates in soil depends on their carbon oxidation state

NASA Astrophysics Data System (ADS)

Gunina, Anna; Smith, Andrew; Jones, Davey; Kuzyakov, Yakov

2017-04-01

Removal of low molecular weight organic substances (LMWOS), originating from plants and microorganisms, from soil solution is regulated by microbial uptake. In addition to the concentration of LMWOS in soil solution, the chemical properties of each substance (e.g. C oxidation state, number of C atoms, number of -COOH groups) can affect their uptake and subsequent partitioning of C within the soil microbial community. The aim of this study was to trace the initial fate of three dominant classes of LMWOS in soil (sugars, carboxylic and amino acids), including their removal from solution and utilization by microorganisms, and to reveal the effect of substance chemical properties on these processes. Soil solution, spiked at natural abundance levels with 14C-labelled glucose, fructose, malate, succinate, formate, alanine or glycine, was added to the soil and 14C was traced in the dissolved organic carbon (DOC), CO2, cytosol and soil organic carbon (SOC) over 24 hours. The half-life time of all LMWOS in the DOC (T1 /2-solution) varied between 0.6-5.0 min showing extremely fast initial uptake of LMWOS. The T1 /2-solution of substances was dependent on C oxidation state, indicating that less oxidized organic substances (with C oxidation state "0") were retained longer in soil solution than oxidized substances. The LMWOS-C T1 /2-fast, characterizing the half-life time of 14C in the fast mineralization pool, ranged between 30 and 80 min, with the T1 /2-fast of carboxylic acids (malic acid) being the fastest and the T1 /2-fast of amino acids (glycine) being the slowest. An absence of correlation between T1 /2-fast and either C oxidation state, number of C atoms, or number of -COOH groups suggests that intercellular metabolic pathways are more important for LMWOS transformation in soil than their basic chemical properties. The CO2 release during LMWOS mineralization accounted for 20-90% of 14C applied. Mineralization of LMWOS was the least for sugars and the greatest for

Engineering the defect state and reducibility of ceria based nanoparticles for improved anti-oxidation performance

NASA Astrophysics Data System (ADS)

Wang, Yan-Jie; Dong, Hao; Lyu, Guang-Ming; Zhang, Huai-Yuan; Ke, Jun; Kang, Li-Qun; Teng, Jia-Li; Sun, Ling-Dong; Si, Rui; Zhang, Jing; Liu, Yan-Jun; Zhang, Ya-Wen; Huang, Yun-Hui; Yan, Chun-Hua

2015-08-01

Due to their excellent anti-oxidation performance, CeO2 nanoparticles receive wide attention in pharmacological application. Deep understanding of the anti-oxidation mechanism of CeO2 nanoparticles is extremely important to develop potent CeO2 nanomaterials for anti-oxidation application. Here, we report a detailed study on the anti-oxidation process of CeO2 nanoparticles. The valence state and coordination structure of Ce are characterized before and after the addition of H2O2 to understand the anti-oxidation mechanism of CeO2 nanoparticles. Adsorbed peroxide species are detected during the anti-oxidation process, which are responsible for the red-shifted UV-vis absorption spectra of CeO2 nanoparticles. Furthermore, the coordination number of Ce in the first coordination shell slightly increased after the addition of H2O2. On the basis of these experimental results, the reactivity of coordination sites for peroxide species is considered to play a key role in the anti-oxidation performance of CeO2 nanoparticles. Furthermore, we present a robust method to engineer the anti-oxidation performance of CeO2 nanoparticles through the modification of the defect state and reducibility by doping with Gd3+. Improved anti-oxidation performance is also observed in cell culture, where the biocompatible CeO2-based nanoparticles can protect INS-1 cells from oxidative stress induced by H2O2, suggesting the potential application of CeO2 nanoparticles in the treatment of diabetes.Due to their excellent anti-oxidation performance, CeO2 nanoparticles receive wide attention in pharmacological application. Deep understanding of the anti-oxidation mechanism of CeO2 nanoparticles is extremely important to develop potent CeO2 nanomaterials for anti-oxidation application. Here, we report a detailed study on the anti-oxidation process of CeO2 nanoparticles. The valence state and coordination structure of Ce are characterized before and after the addition of H2O2 to understand the anti-oxidation

Identification of the iron oxidation state and coordination geometry in iron oxide- and zeolite-based catalysts using pre-edge XAS analysis.

PubMed

Boubnov, Alexey; Lichtenberg, Henning; Mangold, Stefan; Grunwaldt, Jan Dierk

2015-03-01

Analysis of the oxidation state and coordination geometry using pre-edge analysis is attractive for heterogeneous catalysis and materials science, especially for in situ and time-resolved studies or highly diluted systems. In the present study, focus is laid on iron-based catalysts. First a systematic investigation of the pre-edge region of the Fe K-edge using staurolite, FePO4, FeO and α-Fe2O3 as reference compounds for tetrahedral Fe(2+), tetrahedral Fe(3+), octahedral Fe(2+) and octahedral Fe(3+), respectively, is reported. In particular, high-resolution and conventional X-ray absorption spectra are compared, considering that in heterogeneous catalysis and material science a compromise between high-quality spectroscopic data acquisition and simultaneous analysis of functional properties is required. Results, which were obtained from reference spectra acquired with different resolution and quality, demonstrate that this analysis is also applicable to conventionally recorded pre-edge data. For this purpose, subtraction of the edge onset is preferentially carried out using an arctangent and a first-degree polynomial, independent of the resolution and quality of the data. For both standard and high-resolution data, multiplet analysis of pre-edge features has limitations due to weak transitions that cannot be identified. On the other hand, an arbitrary empirical peak fitting assists the analysis in that non-local transitions can be isolated. The analysis of the oxidation state and coordination geometry of the Fe sites using a variogram-based method is shown to be effective for standard-resolution data and leads to the same results as for high-resolution spectra. This method, validated by analysing spectra of reference compounds and their well defined mixtures, is finally applied to track structural changes in a 1% Fe/Al2O3 and a 0.5% Fe/BEA zeolite catalyst during reduction in 5% H2/He. The results, hardly accessible by other techniques, show that Fe(3+) is

Influence of Organic Ligands on the Surface Oxidation State and Magnetic Properties of Iron Oxide Particles

NASA Astrophysics Data System (ADS)

Goroncy, Christian; Saloga, Patrick E. J.; Gruner, Mathias; Schmudde, Madlen; Vonnemann, Jonathan; Otero, Edwige; Haag, Rainer; Graf, Christina

2018-05-01

For the application of iron oxide nanoparticles from thermal decomposition approaches as contrast agents in magnetic resonance imaging (MRI), their initial hydrophobic ligands have to be replaced by hydrophilic ones. This exchange can influence the surface oxidation state and the magnetic properties of the particles. Here, the effect of the anchor group of three organic ligands, citric acid and two catechols, dihydrocaffeic acid and its nitrated derivative nitro dihydrocaffeic acid on iron oxide nanoparticles is evaluated. The oleate ligands of Fe3O4/γ-Fe2O3 nanoparticles prepared by the thermal decomposition of iron oleate were exchanged against the hydrophilic ligands. X-ray absorption spectroscopy, especially X-ray magnetic circular dichroism (XMCD) measurements in the total electron yield (TEY) mode was used to investigate local magnetic and electronic properties of the particles' surface region before and after the ligand exchange. XMCD was combined with charge transfer multiplet calculations which provide information on the contributions of Fe2+ and Fe3+ at different lattice sites, i.e. either in tetrahedral or octahedral environment. The obtained data demonstrate that nitro hydrocaffeic acid leads to least reduction of the magnetizability of the surface region of the iron oxide nanoparticles compared to the two other ligands. For all hydrophilic samples, the proportion of Fe3+ ions in octahedral sites increases at the expense of the Fe2+ in octahedral sites whereas the percentage of Fe3+ in tetrahedral sites hardly changes. These observations suggest that an oxidation process took place, but a selective decrease of the Fe2+ ions in octahedral sites ions due to surface dissolution processes is unlikely. The citrate ligand has the least oxidative effect, whereas the degree of oxidation was similar for both catechol ligands regardless of the nitro group. Twenty-four hours of incubation in isotonic saline has nearly no influences on the magnetic properties of

Chromium oxidation state mapping in human cells

NASA Astrophysics Data System (ADS)

Ortega, R.; Fayard, B.; Salomé, M.; Devès, G.; Susini, J.

2003-03-01

The widespread use of chromium in industrial applications such as chemical production of pigments, refractory brick production, tanning, metallurgy, electroplating, and combustion of fuels has lead to human occupational exposure and to its increased introduction into the environment. Hexavalent chromium compounds are established carcinogens but their mechanism of cell transformation is not known. Up to now, no microanalytical technique was sensitive enough to allow the observation of chromium distribution, and oxidation state identification, within isolated cells at carcinogenic concentrations. In this experiment, we used successfully the ID-21 X-ray microscope to map Cr(VI) and total Cr distributions in cells exposed in vitro to soluble, and insoluble, Cr(VI) compounds. Exposure to soluble compounds, weak carcinogens, resulted in a homogeneous intracellular distribution of Cr, confirming by in situ measurement that Cr is present in the cell nucleus. Cr(VI) was never detected in cells which suggests a mechanism of rapid intracellular reducticn. On the other hand, exposure to insoluble compounds, strong carcinogens, also resulted in a homogeneous distribution of reduced forms of Cr in cells, and their nucleus. However, in this case, Cr(VI)-rich structures were observed into the cells suggesting that carcinogenicity is enhanced when oxidation reactions due to Cr(VI) chronic exposure are associated to Cr-DNA alterations.

Composition and oxidation state of sulfur in atmospheric particulate matter

NASA Astrophysics Data System (ADS)

Longo, Amelia F.; Vine, David J.; King, Laura E.; Oakes, Michelle; Weber, Rodney J.; Huey, Lewis Gregory; Russell, Armistead G.; Ingall, Ellery D.

2016-10-01

The chemical and physical speciation of atmospheric sulfur was investigated in ambient aerosol samples using a combination of sulfur near-edge x-ray fluorescence spectroscopy (S-NEXFS) and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the composition and oxidation state of sulfur in common primary emission sources and ambient particulate matter collected from the greater Atlanta area. Ambient particulate matter samples contained two oxidation states: S0 and S+VI. Ninety-five percent of the individual aerosol particles (> 1 µm) analyzed contain S0. Linear combination fitting revealed that S+VI in ambient aerosol was dominated by ammonium sulfate as well as metal sulfates. The finding of metal sulfates provides further evidence for acidic reactions that solubilize metals, such as iron, during atmospheric transport. Emission sources, including biomass burning, coal fly ash, gasoline, diesel, volcanic ash, and aerosolized Atlanta soil, and the commercially available bacterium Bacillus subtilis, contained only S+VI. A commercially available Azotobacter vinelandii sample contained approximately equal proportions of S0 and S+VI. S0 in individual aerosol particles most likely originates from primary emission sources, such as aerosolized bacteria or incomplete combustion.

Access to benznidazole for Chagas disease in the United States-Cautious optimism?

PubMed

Alpern, Jonathan D; Lopez-Velez, Rogelio; Stauffer, William M

2017-09-01

Drugs for neglected tropical diseases (NTD) are being excessively priced in the United States. Benznidazole, the first-line drug for Chagas disease, may become approved by the Food and Drug Administration (FDA) and manufactured by a private company in the US, thus placing it at risk of similar pricing. Chagas disease is an NTD caused by Trypanosoma cruzi; it is endemic to Latin America, infecting 8 million individuals. Human migration has changed the epidemiology causing nonendemic countries to face increased challenges in diagnosing and managing patients with Chagas disease. Only 2 drugs exist with proven efficacy: benznidazole and nifurtimox. Benznidazole has historically faced supply problems and drug shortages, limiting accessibility. In the US, it is currently only available under an investigational new drug (IND) protocol from the CDC and is provided free of charge to patients. However, 2 companies have stated that they intend to submit a New Drug Application (NDA) for FDA approval. Based on recent history of companies acquiring licensing rights for NTD drugs in the US with limited availability, it is likely that benznidazole will become excessively priced by the manufacturer-paradoxically making it less accessible. However, if the companies can be taken at their word, there may be reason for optimism.

Oxidized Nitrogen Balance over 15 Months at Rural and Urban New York State Locations

NASA Astrophysics Data System (ADS)

Schwab, J. J.; Ninneman, M.; Marto, J.; Edgerton, E. S.; Blanchard, C. L.; Shaw, S. L.

2017-12-01

Continuous measurements of oxidized nitrogen species (NO, NO2, and HNO3), families of species (NOy, alkyl nitrates [or ANs], and peroxyacetyl nitrates [or PANs]), and particle nitrate (pNO3) were carried out for a fifteen-month period from August 2016 through October 2017 at two locations in New York State. The two sites were a rural research station at Pinnacle State Park in Addison, NY and an urban research station at Queens College in New York City. Four different chemiluminescence analyzers with various converters and denuders were employed to make these measurements. Instrumentation used for the study will be described, as well as some of the challenges created by combining data from these independent analyzers to address the oxidized nitrogen budget at the two sites. The Pinnacle State Park site often experiences quite clean air with low ppb levels of total NOy and a greater fraction of oxidized nitrogen products (NOz species). This contrasts with the urban Queens College location, which experiences stronger NOx sources. Seasonal differences in the NOx/NOy and NOz/NOy ratios, and the makeup of the NOz species, are also significant and will be explored in the presentation.

Effect of Pr Valence State on Interfacial Structure and Electrical Properties of Pr Oxide/PrON/Ge Gate Stack Structure

NASA Astrophysics Data System (ADS)

Kato, Kimihiko; Sakashita, Mitsuo; Takeuchi, Wakana; Kondo, Hiroki; Nakatsuka, Osamu; Zaima, Shigeaki

2011-04-01

In this study, we investigated the valence state and chemical bonding state of Pr in a Pr oxide/PrON/Ge structure. We clarified the relationship between the valence state of Pr and the Pr oxide/Ge interfacial reaction using Pr oxide/Ge and Pr oxide/PrON/Ge samples. We found the formation of three Pr oxide phases in Pr oxide films; hexagonal Pr2O3 (h-Pr2O3) (Pr3+), cubic Pr2O3 (c-Pr2O3) (Pr3+), and c-PrO2 (Pr4+). We also investigated the effect of a nitride interlayer on the interfacial reaction in Pr oxide/Ge gate stacks. In a sample with a nitride interlayer (Pr oxide/PrON/Ge), metallic Pr-Pr bonds are also formed in the c-Pr2O3 film. After annealing in H2 ambient, the diffusion of Ge into Pr oxide is not observed in this sample. Pr-Pr bonds probably prevent the interfacial reaction and Ge oxide formation, considering that the oxygen chemical potential of this film is lower than that of a GeO2/Ge system. On the other hand, the rapid thermal oxidation (RTO) treatment terminates the O vacancies and defects in c-Pr2O3. As a result, c-PrO2 with tetravalent Pr is formed in the Pr oxide/PrON/Ge sample with RTO. In this sample, the leakage current density is effectively decreased in comparison with the sample without RTO. Hydrogen termination works effectively in Pr oxide/PrON/Ge samples with and without RTO, and we can achieve an interface state density of as low as 4 ×1011 eV-1·cm-2.

Effect of surface state on the oxidation behavior of welded 308L in simulated nominal primary water of PWR

NASA Astrophysics Data System (ADS)

Ming, Hongliang; Zhang, Zhiming; Wang, Jiazhen; Zhu, Ruolin; Ding, Jie; Wang, Jianqiu; Han, En-Hou; Ke, Wei

2015-05-01

The oxidation behavior of 308L weld metal (WM) with different surface state in the simulated nominal primary water of pressurized water reactor (PWR) was studied by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analyzer and X-ray photoelectron spectroscopy (XPS). After 480 h immersion, a duplex oxide film composed of a Fe-rich outer layer (Fe3O4, Fe2O3 and a small amount of NiFe2O4, Ni(OH)2, Cr(OH)3 and (Ni, Fe)Cr2O4) and a Cr-rich inner layer (FeCr2O4 and NiCr2O4) can be formed on the 308L WM samples with different surface state. The surface state has no influence on the phase composition of the oxide films but obviously affects the thickness of the oxide films and the morphology of the oxides (number & size). With increasing the density of dislocations and subgrain boundaries in the cold-worked superficial layer, the thickness of the oxide film, the number and size of the oxides decrease.

The oxidation state, and sulfur and Cu contents of arc magmas: implications for metallogeny

NASA Astrophysics Data System (ADS)

Richards, Jeremy P.

2015-09-01

Global data for measured Fe2O3/FeO ratios and Cu contents in unaltered volcanic and intrusive arc rocks indicate that, on average, they are slightly more oxidized than other magmas derived from depleted upper mantle (such as MORB), but contain similar Cu contents across their compositional ranges. Although Cu scatters to elevated values in some intermediate composition samples, the bulk of the data show a steady but gentle trend to lower concentrations with differentiation, reaching modal values of 50-100 ppm in andesitic rocks. These data suggest that Cu is mildly compatible during partial melting and fractionation processes, likely reflecting minor degrees of sulfide saturation throughout the magmatic cycle. However, the volume of sulfides must be small such that significant proportions of the metal content remain in the magma during fractionation to intermediate compositions. Previous studies have shown that andesitic magmas containing 50 ppm Cu can readily form large porphyry-type Cu deposits upon emplacement in the upper crust. A review of the literature suggests that the elevated oxidation state in the asthenospheric mantle wedge source of arc magmas (ΔFMQ ≈ + 1 ± 1) derives from the subduction of seawater-altered and oxidized oceanic crust, and is transmitted into the mantle wedge via prograde metamorphic dehydration fluids carrying sulfate and other oxidizing components. Progressive hydration and oxidation of the mantle wedge may take up to 10 m.y. to reach a steady state from the onset of subduction, explaining the rarity of porphyry deposits in primitive island arcs, and the late formation of porphyries in continental arc magmatic cycles. Magmas generated from this metasomatized and moderately oxidized mantle source will be hydrous basalts containing high concentrations of sulfur, mainly dissolved as sulfate or sulfite. Some condensed sulfides (melt or minerals) may be present due to the high overall fS2, despite the moderately high oxidation state

Clay-mediated reactions of HCN oligomers - The effect of the oxidation state of the clay

NASA Technical Reports Server (NTRS)

Ferris, J. P.; Alwis, K. W.; Edelson, E. H.; Mount, N.; Hagan, W. J., Jr.

1981-01-01

Montmorillonite clays which contain Fe(III) inhibit the oligomerization of aqueous solutions of HCN. The inhibitory effect is due to the rapid oxidation of diaminomaleonitrile, a key intermediate in HCN oligomerization, by the Fe(III) incorporated into the aluminosilicate lattice of the clay. The Fe(III) oxidizes diaminomaleonitrile to diiminosuccinonitrile, a compound which is rapidly hydrolyzed to HCN and oxalic acid derivatives. Diaminomaleonitrile is not oxidized when Fe(III) in the montmorillonite is reduced with hydrazine. The oxidation state of the clay is an important variable in experiments designed to simulate clay catalysis on the primitive earth.

Adaptation of oxidative phosphorylation to photoperiod-induced seasonal metabolic states in migratory songbirds.

PubMed

Trivedi, Amit Kumar; Malik, Shalie; Rani, Sangeeta; Kumar, Vinod

2015-06-01

Eukaryotic cells produce chemical energy in the form of ATP by oxidative phosphorylation of metabolic fuels via a series of enzyme mediated biochemical reactions. We propose that the rates of these reactions are altered, as per energy needs of the seasonal metabolic states in avian migrants. To investigate this, blackheaded buntings were photoperiodically induced with non-migratory, premigratory, migratory and post-migratory phenotypes. High plasma levels of free fatty acids, citrate (an intermediate that begins the TCA cycle) and malate dehydrogenase (mdh, an enzyme involved at the end of the TCA cycle) confirmed increased availability of metabolic reserves and substrates to the TCA cycle during the premigratory and migratory states, respectively. Further, daily expression pattern of genes coding for enzymes involved in the oxidative decarboxylation of pyruvate to acetyl-CoA (pdc and pdk) and oxidative phosphorylation in the TCA cycle (cs, odgh, sdhd and mdh) was monitored in the hypothalamus and liver. Reciprocal relationship between pdc and pdk expressions conformed with the altered requirements of acetyl-CoA for the TCA cycle in different metabolic states. Except for pdk, all genes had a daily expression pattern, with high mRNA expression during the day in the premigratory/migratory phenotypes, and at night (cs, odhg, sdhd and mdh) in the nonmigratory phenotype. Differences in mRNA expression patterns of pdc, sdhd and mdh, but not of pdk, cs and odgh, between the hypothalamus and liver indicated a tissue dependent metabolism in buntings. These results suggest the adaptation of oxidative phosphorylation pathway(s) at gene levels to the seasonal alternations in metabolism in migratory songbirds. Copyright © 2015 Elsevier Inc. All rights reserved.

The influence of iridium chemical oxidation state on the performance and durability of oxygen evolution catalysts in PEM electrolysis

NASA Astrophysics Data System (ADS)

Siracusano, S.; Baglio, V.; Grigoriev, S. A.; Merlo, L.; Fateev, V. N.; Aricò, A. S.

2017-10-01

Nanosized Ir-black (3 nm) and Ir-oxide (5 nm) oxygen evolution electrocatalysts showing high performance in polymer electrolyte membrane (PEM) water electrolysis based on Aquivion® short-side chain ionomer membrane are investigated to understand the role of the Ir oxidation state on the electrocatalytic activity and stability. Despite the smaller mean crystallite size, the Ir-black electrocatalyst shows significantly lower initial performance than the Ir-oxide. During operation at high current density, the Ir-black shows a decrease of cell potential with time whereas the Ir-oxide catalyst shows increasing cell potential resulting in a degradation rate of about 10 μV/h, approaching 1000 h. The unusual behaviour of the Ir-black results from the oxidation of metallic Ir to IrOx. The Ir-oxide catalyst shows instead a hydrated structure on the surface and a negative shift of about 0.5 eV for the Ir 4f binding energy after 1000 h electrolysis operation. This corresponds to the formation of a sub-stoichiometric Ir-oxide on the surface. These results indicate that a hydrated IrO2 with high oxidation state on the surface is favourable in decreasing the oxygen evolution overpotential. Modifications of the Ir chemical oxidation state during operation can affect significantly the catalytic activity and durability of the electrolysis system.

Measurement of soil carbon oxidation state and oxidative ratio by 13C nuclear magnetic resonance

USGS Publications Warehouse

Hockaday, W.C.; Masiello, C.A.; Randerson, J.T.; Smernik, R.J.; Baldock, J.A.; Chadwick, O.A.; Harden, J.W.

2009-01-01

The oxidative ratio (OR) of the net ecosystem carbon balance is the ratio of net O2 and CO2 fluxes resulting from photosynthesis, respiration, decomposition, and other lateral and vertical carbon flows. The OR of the terrestrial biosphere must be well characterized to accurately estimate the terrestrial CO2 sink using atmospheric measurements of changing O2 and CO2 levels. To estimate the OR of the terrestrial biosphere, measurements are needed of changes in the OR of aboveground and belowground carbon pools associated with decadal timescale disturbances (e.g., land use change and fire). The OR of aboveground pools can be measured using conventional approaches including elemental analysis. However, measuring the OR of soil carbon pools is technically challenging, and few soil OR data are available. In this paper we test three solid-state nuclear magnetic resonance (NMR) techniques for measuring soil OR, all based on measurements of the closely related parameter, organic carbon oxidation state (Cox). Two of the three techniques make use of a molecular mixing model which converts NMR spectra into concentrations of a standard suite of biological molecules of known C ox. The third technique assigns Cox values to each peak in the NMR spectrum. We assess error associated with each technique using pure chemical compounds and plant biomass standards whose Cox and OR values can be directly measured by elemental analyses. The most accurate technique, direct polarization solid-state 13C NMR with the molecular mixing model, agrees with elemental analyses to ??0.036 Cox units (??0.009 OR units). Using this technique, we show a large natural variability in soil Cox and OR values. Soil Cox values have a mean of -0.26 and a range from -0.45 to 0.30, corresponding to OR values of 1.08 ?? 0.06 and a range from 0.96 to 1.22. We also estimate the OR of the carbon flux from a boreal forest fire. Analysis of soils from nearby intact soil profiles imply that soil carbon losses associated

Patient access to new cancer drugs in the United States and Australia.

PubMed

Wilson, Andrew; Cohen, Joshua

2011-01-01

In light of the current debate on the use value and potential impact of comparative effectiveness research on patient access, it may prove insightful to compare a health-care system that systematically bases its reimbursement decisions on comparative effectiveness evidence with the United States (US) system that hitherto has only been informed by such evidence on an ad hoc basis. For a set of 2000-2009 approved new molecular entities and biologics indicated for cancer, we compared patient access between US Medicare and Australian Pharmaceutical Benefits Scheme (PBS) beneficiaries. Here, access is defined in terms of marketing availability, payer coverage, and patient out-of-pocket costs. Although 34 drugs and biologics were approved for cancer in the US, just more than one-third (35%) were ultimately covered by the Australian PBS. The PBS also placed more restrictions on use. On the other hand, prices and patient out-of-pocket costs were greater for the US Medicare population. Our analysis points to a possible trade-off in market access to oncology drugs. Although more oncology drugs are available in the US and a higher percentage of available drugs are covered, the evidence-based approach adopted by Australia has contributed to reduced prices, thereby improving affordability for payers and patients for those medications deemed cost-effective by the reimbursement authority. Copyright © 2011 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

GaAs-oxide interface states - A gigantic photoionization effect and its implications to the origin of these states

NASA Technical Reports Server (NTRS)

Lagowski, J.; Walukiewicz, W.; Kazior, T. E.; Gatos, H. C.; Siejka, J.

1981-01-01

Gigantic photoionization was discovered on GaAs-oxide interfaces leading to the discharge of deep surface states with rates exceeding 1000 times those of photoionization transitions to the conduction band. It exhibits a peak similar to acceptor-donor transitions and is explained as due to energy transfer from photo-excited donor-acceptor pairs to deep surface states. This new process indicates the presence of significant concentrations of shallow donor and acceptor levels not recognized in previous interface models.

The control of iron-induced oxidative damage in isolated rat-liver mitochondria by respiration state and ascorbate.

PubMed

Burkitt, M J; Gilbert, B C

1989-01-01

The reaction of iron (II) with H2O2 is believed to generate highly reactive species (e.g. .OH) capable of initiating biological damage. This study investigates the possibility that the severity of oxidative damage induced by iron in hepatic mitochondria is determined by the level of mitochondrial-H2O2 generation, which is believed to be particularly prominent in state-4 respiration. Iron-induced damage is found to be greater in state-4 than in state-3 respiration. Experiments using uncoupling agents and Ca++ to mimic state-3 conditions indicate that this effect reflects differences in the steady-state oxidation-level of the electron carriers of the respiratory chain (and hence the level of H2O2-generation), rather than changes in redox potential or transportation of the metal-ion. Evidence is also presented for a mechanism in which Fe(II) and H2O2 react inside the mitochondrial matrix. Ascorbate (vitamin C) is shown to be pro-oxidant in this system, except when present at very high concentration when it becomes antioxidant in nature.

Homoleptic Ce(III) and Ce(IV) Nitroxide Complexes: Significant Stabilization of the 4+ Oxidation State

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

Bogart, Justin A.; Lewis, Andrew J.; Medling, Scott A.

2014-06-25

Electrochemical experiments performed on the complex Ce-IV[2-((BuNO)-Bu-t)py](4), where [2-((BuNO)-Bu-t)py](-) = N-tert-butyl-N-2-pyridylnitroxide, indicate a 2.51 V stabilization of the 4+ oxidation state of Ce compared to [(Bu4N)-Bu-n](2)[Ce(NO3)(6)] in acetonitrile and a 2.95 V stabilization compared to the standard potential for the ion under aqueous conditions. Density functional theory calculations suggest that this preference for the higher oxidation state is a result of the tetrakis(nitroxide) ligand framework at the Ce cation, which allows for effective electron donation into, and partial covalent overlap with, vacant 4f orbitals with delta symmetry. The results speak to the behavior of CeO2 and related solid solutions inmore » oxygen uptake and transport applications, in particular an inherent local character of bonding that stabilizes the 4+ oxidation state. The results indicate a cerium(IV) complex that has been stabilized to an unprecedented degree through tuning of its ligand-field environment.« less

Status in calculating electronic excited states in transition metal oxides from first principles.

PubMed

Bendavid, Leah Isseroff; Carter, Emily Ann

2014-01-01

Characterization of excitations in transition metal oxides is a crucial step in the development of these materials for photonic and optoelectronic applications. However, many transition metal oxides are considered to be strongly correlated materials, and their complex electronic structure is challenging to model with many established quantum mechanical techniques. We review state-of-the-art first-principles methods to calculate charged and neutral excited states in extended materials, and discuss their application to transition metal oxides. We briefly discuss developments in density functional theory (DFT) to calculate fundamental band gaps, and introduce time-dependent DFT, which can model neutral excitations. Charged excitations can be described within the framework of many-body perturbation theory based on Green's functions techniques, which predominantly employs the GW approximation to the self-energy to facilitate a feasible solution to the quasiparticle equations. We review the various implementations of the GW approximation and evaluate each approach in its calculation of fundamental band gaps of many transition metal oxides. We also briefly review the related Bethe-Salpeter equation (BSE), which introduces an electron-hole interaction between GW-derived quasiparticles to describe accurately neutral excitations. Embedded correlated wavefunction theory is another framework used to model localized neutral or charged excitations in extended materials. Here, the electronic structure of a small cluster is modeled within correlated wavefunction theory, while its coupling to its environment is represented by an embedding potential. We review a number of techniques to represent this background potential, including electrostatic representations and electron density-based methods, and evaluate their application to transition metal oxides.

Coupled interactions between volatile activity and Fe oxidation state during arc crustal processes

USGS Publications Warehouse

Humphreys, Madeleine C.S.; Brooker, R; Fraser, D.C.; Burgisser, A; Mangan, Margaret T.; McCammon, C

2015-01-01

Arc magmas erupted at the Earth’s surface are commonly more oxidized than those produced at mid-ocean ridges. Possible explanations for this high oxidation state are that the transfer of fluids during the subduction process results in direct oxidation of the sub-arc mantle wedge, or that oxidation is caused by the effect of later crustal processes, including protracted fractionation and degassing of volatile-rich magmas. This study sets out to investigate the effect of disequilibrium crustal processes that may involve coupled changes in H2O content and Fe oxidation state, by examining the degassing and hydration of sulphur-free rhyolites. We show that experimentally hydrated melts record strong increases in Fe3+/∑Fe with increasing H2O concentration as a result of changes in water activity. This is relevant for the passage of H2O-undersaturated melts from the deep crust towards shallow crustal storage regions, and raises the possibility that vertical variations in fO2 might develop within arc crust. Conversely, degassing experiments produce an increase in Fe3+/∑Fe with decreasing H2O concentration. In this case the oxidation is explained by loss of H2 as well as H2O into bubbles during decompression, consistent with thermodynamic modelling, and is relevant for magmas undergoing shallow degassing en route to the surface. We discuss these results in the context of the possible controls on fO2 during the generation, storage and ascent of magmas in arc settings, in particular considering the timescales of equilibration relative to observation as this affects the quality of the petrological record of magmatic fO2.

Chelation and stabilization of berkelium in oxidation state +IV

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

Deblonde, Gauthier J. -P.; Sturzbecher-Hoehne, Manuel; Rupert, Peter B.

Berkelium (Bk) has been predicted to be the only transplutonium element able to exhibit both +III and +IV oxidation states in solution, but evidence of a stable oxidized Bk chelate has so far remained elusive. Here, in this work, we describe the stabilization of the heaviest 4+ ion of the periodic table, under mild aqueous conditions, using a siderophore derivative. The resulting Bk(IV) complex exhibits luminescence via sensitization through an intramolecular antenna effect. This neutral Bk(IV) coordination compound is not sequestered by the protein siderocalin - a mammalian metal transporter - in contrast to the negatively charged species obtained withmore » neighbouring trivalent actinides americium, curium and californium (Cf). The corresponding Cf(III)-ligand-protein ternary adduct was characterized by X-ray diffraction analysis. Finally, combined with theoretical predictions, these data add significant insight to the field of transplutonium chemistry, and may lead to innovative Bk separation and purification processes.« less

Chelation and stabilization of berkelium in oxidation state +IV

DOE PAGES

Deblonde, Gauthier J. -P.; Sturzbecher-Hoehne, Manuel; Rupert, Peter B.; ...

2017-04-10

Berkelium (Bk) has been predicted to be the only transplutonium element able to exhibit both +III and +IV oxidation states in solution, but evidence of a stable oxidized Bk chelate has so far remained elusive. Here, in this work, we describe the stabilization of the heaviest 4+ ion of the periodic table, under mild aqueous conditions, using a siderophore derivative. The resulting Bk(IV) complex exhibits luminescence via sensitization through an intramolecular antenna effect. This neutral Bk(IV) coordination compound is not sequestered by the protein siderocalin - a mammalian metal transporter - in contrast to the negatively charged species obtained withmore » neighbouring trivalent actinides americium, curium and californium (Cf). The corresponding Cf(III)-ligand-protein ternary adduct was characterized by X-ray diffraction analysis. Finally, combined with theoretical predictions, these data add significant insight to the field of transplutonium chemistry, and may lead to innovative Bk separation and purification processes.« less

Access to healthcare for undocumented migrants in France: a critical examination of State Medical Assistance.

PubMed

André, Jean-Marie; Azzedine, Fabienne

2016-01-01

In France in 2012, of the total population of 65.2 million, 8.7 % were migrants. After being the third principal host country, France is now the 6th highest host country in the OECD. Since the 1980's numerous Acts have been passed by parliament on immigration issues. In 2000 the Universal Health Cover (Couverture Maladie Universelle) was created as health coverage for all residents of France. At the same time the State Medical Assistance (Aide Médicale de l'Etat) was created as health protection for undocumented migrants. Since the creation of this scheme, it has been the object of many political debates which call it into question, on account of its cost, perceived fraud, and the legitimacy of a social protection for undocumented migrants. Recently, access to State Medical Assistance has been made difficult by introducing conditions of residence and financial contributions. After a reports' analysis on institutional, associative, research studies and European recommendations, we note that all reports converge on the necessity of health protection for undocumented migrants. The major reasons are humanitarian, respect of European and International conventions, for public health, and financial. Moreover, fraud allegations have proved to be unfounded. Finally, State Medical Assistance is underused: in 2014 data from Médecins du Monde shows that only 10.2 % of undocumented migrant patients in their health facilities have access to this scheme. We conclude that the political debate concerning the State Medical Assistance should be about its under-utilisation, its improvement, its merger with the Universal Health Cover, and not its elimination. Moreover, the current debates regarding this scheme stigmatize this population, which is already precarious, making it more difficult for migrants to access healthcare, and generally, weaken national social cohesion.

The Challenge to States: Preserving College Access and Affordability in a Time of Crisis

ERIC Educational Resources Information Center

National Center for Public Policy and Higher Education, 2009

2009-01-01

The American Recovery and Reinvestment Act of 2009 represents both an opportunity and a challenge for states to set priorities. A substantial portion of these one-time federal funds can be used to reposition higher education strategically to protect access and quality and to stimulate the increased cost effectiveness and degree productivity…

Arsenic (+3 oxidation state) methyltransferase genotype affects steady-state distribution and clearance of arsenic in arsenate-treated mice

EPA Science Inventory

Arsenic (+3 oxidation state) methyltransferase (As3mt) catalyzes formation of mono-, di-, and tri-methylated metabolites of inorganic arsenic. Distribution and retention of arsenic were compared in adult female As3mt knockout mice and wild-type C57BL/6 mice using a regimen in whi...

Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy.

PubMed

Wang, Y F; Singh, Shashi B; Limaye, Mukta V; Shao, Y C; Hsieh, S H; Chen, L Y; Hsueh, H C; Wang, H T; Chiou, J W; Yeh, Y C; Chen, C W; Chen, C H; Ray, Sekhar C; Wang, J; Pong, W F; Takagi, Y; Ohigashi, T; Yokoyama, T; Kosugi, N

2015-10-20

This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ*)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ*)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ*)-derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets.

Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy

PubMed Central

Wang, Y. F.; Singh, Shashi B.; Limaye, Mukta V.; Shao, Y. C.; Hsieh, S. H.; Chen, L. Y.; Hsueh, H. C.; Wang, H. T.; Chiou, J. W.; Yeh, Y. C.; Chen, C. W.; Chen, C. H.; Ray, Sekhar C.; Wang, J.; Pong, W. F.; Takagi, Y.; Ohigashi, T.; Yokoyama, T.; Kosugi, N.

2015-01-01

This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ*)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ*)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ*)-derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets. PMID:26481557

Disparities and access to healthy food in the United States: A review of food deserts literature.

PubMed

Walker, Renee E; Keane, Christopher R; Burke, Jessica G

2010-09-01

Increasingly, studies are focusing on the role the local food environment plays in residents' ability to purchase affordable, healthy and nutritious foods. In a food desert, an area devoid of a supermarket, access to healthy food is limited. We conducted a systematic review of studies that focused on food access and food desert research in the United States. The 31 studies identified utilized 9 measures to assess food access. Results from these studies can be summarized primarily into four major statements. Findings from other countries offer insight into ways, in which future research, policy development and program implementation in the U.S. may continue to be explored. Copyright 2010 Elsevier Ltd. All rights reserved.

Assessing the oxidation states and structural stability of the Ce analogue of brannerite

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

Aluri, Esther Rani; Bachiu, Lisa M.; Grosvenor, Andrew P.

2017-07-04

The Ce-containing analogue of brannerite (ie, UTi2O6) was previously considered to be stoichiometric (ie, CeTi2O6); however, it has recently been determined that the material is O deficient. This oxygen-deficient material has been suggested to be charged balanced by the presence of a minor concentration of Ce3+ or by the A-site being cation deficient with the Ce oxidation state being 4+. A variety of Ti-containing oxides (including brannerite) have been investigated as potential nuclear wasteforms, and it is necessary to understand the electronic structure of a proposed nuclear wasteform material as well as how the structure responds to radiation from incorporatedmore » waste elements. The radiation resistance of a material can be simulated by ion implantation. The objective of this study was to confirm the Ce oxidation state in the cation- and oxygen-deficient material (ie, Ce0.94Ti2O6 - δ) and to determine how radiation damage affects this material. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy were used to study Ce0.94Ti2O6 - δ before and after being implanted with 2 MeV Au- ions. Analysis of the Ce 3d XPS spectra from the as-synthesized samples by using a previously developed fitting method has unequivocally shown that Ce adopts both 4+ (major) and 3+ (minor) oxidation states, which was confirmed by examination of magnetic susceptibility data. Analysis of XPS and X-ray absorption near-edge spectroscopy spectra from ion-implanted materials showed that both Ce and Ti were reduced because of radiation damage and that the local coordination environments of the cations are greatly affected by radiation damage.« less

Obesity-Associated Oxidative Stress: Strategies Finalized to Improve Redox State

PubMed Central

Savini, Isabella; Catani, Maria Valeria; Evangelista, Daniela; Gasperi, Valeria; Avigliano, Luciana

2013-01-01

Obesity represents a major risk factor for a plethora of severe diseases, including diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and cancer. It is often accompanied by an increased risk of mortality and, in the case of non-fatal health problems, the quality of life is impaired because of associated conditions, including sleep apnea, respiratory problems, osteoarthritis, and infertility. Recent evidence suggests that oxidative stress may be the mechanistic link between obesity and related complications. In obese patients, antioxidant defenses are lower than normal weight counterparts and their levels inversely correlate with central adiposity; obesity is also characterized by enhanced levels of reactive oxygen or nitrogen species. Inadequacy of antioxidant defenses probably relies on different factors: obese individuals may have a lower intake of antioxidant- and phytochemical-rich foods, such as fruits, vegetables, and legumes; otherwise, consumption of antioxidant nutrients is normal, but obese individuals may have an increased utilization of these molecules, likewise to that reported in diabetic patients and smokers. Also inadequate physical activity may account for a decreased antioxidant state. In this review, we describe current concepts in the meaning of obesity as a state of chronic oxidative stress and the potential interventions to improve redox balance. PMID:23698776

A summary of public access defibrillation laws, United States, 2010.

PubMed

Gilchrist, Siobhan; Schieb, Linda; Mukhtar, Qaiser; Valderrama, Amy; Zhang, Guangyu; Yoon, Paula; Schooley, Michael

2012-01-01

On average, less than 8% of people who experience an out-of-hospital cardiac arrest survive. However, death from sudden cardiac arrest is preventable if a bystander quickly retrieves and applies an automated external defibrillator (AED). Public access defibrillation (PAD) policies have been enacted to create programs that increase the public availability of these devices. The objective of this study was to describe each state's legal requirements for recommended PAD program elements. We reviewed state laws and described the extent to which 13 PAD program elements are mandated in each state. No jurisdiction requires all 13 PAD program elements, 18% require at least 10 elements, and 31% require 3 or fewer elements. All jurisdictions provide some level of immunity to AED users, 60% require PAD maintenance, 59% require emergency medical service notification, 55% impose training requirements, and 41% require medical oversight. Few jurisdictions require a quality improvement process. PAD programs in many states are at risk of failure because critical elements such as maintenance, medical oversight, emergency medical service notification, and continuous quality improvement are not required. Policy makers should consider strengthening PAD policies by enacting laws that can reduce the time from collapse to shock, such as requiring the strategic placement of AEDs in high-risk locations or mandatory PAD registries that are coordinated with local EMS and dispatch centers. Further research is needed to identify the most effective PAD policies for increasing AED use by lay persons and improving survival rates.

Bolide impacts and the oxidation state of carbon in the earth's early atmosphere

NASA Technical Reports Server (NTRS)

Kasting, James F.

1990-01-01

A one-dimensional photochemical model was used to examine the effect of bolide impacts on the oxidation state of earth's primitive atmosphere. The impact rate should have been high prior to 3.8 Ga before present, based on evidence derived from the moon. Impacts of comets or carbonaceous asteroids should have enhanced the atmospheric CO/CO2 ratio by bringing in CO ice and/or organic carbon that can be oxidized to CO in the impact plume. Ordinary chondritic impactors would contain elemental iron that could have reacted with ambient CO2 to give CO. Nitric oxide (NO) should also have been produced by reaction between ambient CO2 and N2 in the hot impact plumes. High NO concentrations increase the atmospheric CO/CO2 ratio by increasing the rainout rate of oxidized gases. According to the model, atmospheric CO/CO2 ratios of unity or greater are possible during the first several hundred million years of earth's history, provided that dissolved CO was not rapidly oxidized to bicarbonate in the ocean.

Food access and cost in American Indian communities in Washington State.

PubMed

O'Connell, Meghan; Buchwald, Dedra S; Duncan, Glen E

2011-09-01

Limited access to foods that make up a nutritious diet at minimal cost may influence eating behaviors and, ultimately, obesity. This study examined the number and type of food stores (convenience, grocery, supermarket) on federal reservations in Washington State, and the availability and cost of foods in the US Department of Agriculture Community Food Security Assessment Toolkit market basket, to describe the food environment of American Indians. Stores were identified by telephone survey of tribal headquarters, a commercial database, and on-site visitation. Foods were assessed using a standardized instrument containing 68 items in seven major food groups during April and May 2009. Store type and availability and cost of foods were recorded on a checklist. Fifty stores were identified on 22 American Indian reservations, including 25 convenience, 16 grocery, and 9 supermarkets. Across all stores, about 38% of checklist items were available, with supermarkets having the most and convenience stores the fewest. Foods from the dairy and sugars/sweets groups were the most prevalent, while fresh fruits/vegetables were the least. Cost of the most commonly available items was lowest in supermarkets. Seventeen reservations did not have a supermarket on their reservation, and the nearest off-reservation supermarket was about 10 miles from the tribe's headquarters, which was used as the standard for distance calculations. These results demonstrate that American Indians living on federal reservations in Washington State may have limited access to foods that make up a nutritious diet at minimal cost. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

Study of GaAs-oxide interface by transient capacitance spectroscopy - Discrete energy interface states

NASA Technical Reports Server (NTRS)

Kamieniecki, E.; Kazior, T. E.; Lagowski, J.; Gatos, H. C.

1980-01-01

Interface states and bulk GaAs energy levels were simultaneously investigated in GaAs MOS structures prepared by anodic oxidation. These two types of energy levels were successfully distinguished by carrying out a comparative analysis of deep level transient capacitance spectra of the MOS structures and MS structures prepared on the same samples of epitaxially grown GaAs. The identification and study of the interface states and bulk levels was also performed by investigating the transient capacitance spectra as a function of the filling pulse magnitude. It was found that in the GaAs-anodic oxide interface there are states present with a discrete energy rather than with a continuous energy distribution. The value of the capture cross section of the interface states was found to be 10 to the 14th to 10 to the 15th/sq cm, which is more accurate than the extremely large values of 10 to the -8th to 10 to the -9th/sq cm reported on the basis of conductance measurements.

Estimating financial resources for universal access to sexual reproductive health care: Evidence from two states in India.

PubMed

Rout, Sarit Kumar; Pradhan, Jalandhar; Choudhury, Sarmistha

2016-10-01

India has made insignificant progress towards achieving universal access to sexual and reproductive health (SRH). One of the key inputs for achieving universal access to SRH is financial resources. Given this, many international agencies including the UN are emphasising on monitoring the financial progress towards achieving SRH. To generate evidence on spending on SRH from various sources - (government, household, international donors and NGOs) to improve the accountability of the government towards SRH goal. Adapting a sub account framework of the NHA, this paper investigated the SRH expenditure of the two divergent states of India. The data were collected from government, households (NSSO), and foreign donors and were classified as per the International Classification of Health Accounts (ICHA). Total SRH expenditure is less than one percent of SGDP from all sources in each state. Among the sources, government's spending on SRH is more than household. A large part of household spending is on curative care which has implications for accessing services by the poor. In spite of data constraints, this paper presents a comprehensive analysis on SRH spending, which is critical for monitoring the commitment towards universal access to SRH. This evidence can be used for further improving data quality for RCH account in LMICs. Copyright © 2016 Elsevier B.V. All rights reserved.

SNC Oxygen Fugacity Recorded in Pyroxenes and its Implications for the Oxidation State of the Martian Interior: An Experimental and Analytical Study

NASA Technical Reports Server (NTRS)

McCanta, M. C.; Rutherford, M. J.

2003-01-01

Knowledge of the oxidation state of a magma is critical as it is one of the parameters which controls the nature and composition of the resulting crystals. In terrestrial magmatic systems, oxygen fugacity (fo2) is known to vary by over nine orders of magnitude. With variations of this magnitude, understanding the compositional differences, phase changes, and crystallization sequence variations, caused by the magma fo2, is essential in deciphering the origin of all igneous rocks. Magmatic oxidation state is of great importance in that it reflects the degree of oxidation of the source region and can provide insight into magmatic processes, such as metasomatism, degassing, and assimilation, which may have changed them. Carmichael [1991] argues that most magmas are unlikely to have their redox states altered from those of their source region. This assumption allows for estimation of the oxidation state of planetary interiors. Conversely, it is known that the fo2 of the magma can be affected by other processes, which occur outside of the source region and therefore, the oxidation state may record those too. Processes which could overprint source region fugacities include melt dehydrogenation or other volatile loss, water or melt infiltration, or assimilation of oxidized or reduced wallrock. Understanding which of these processes is responsible for the redox state of a magma can provide crucial information regarding igneous processes and other forces active in the region. The composition of the SNC basalts and their widely varying proposed oxidation states raise some interesting questions. Do the SNC meteorites have an oxidized or reduced signature? What was the oxygen fugacity of the SNC source region at the time of melt generation? Is the fugacity calculated for the various SNC samples the fugacity of the magma source region or was it overprinted by later events? Are there different oxidation states in the Martian interior or a single one? This proposal seeks to

The relationship between skin aging and steady state ultraweak photon emission as an indicator of skin oxidative stress in vivo.

PubMed

Gabe, Y; Osanai, O; Takema, Y

2014-08-01

Ultraweak photon emission (UPE) is one potential method to evaluate the oxidative status of the skin in vivo. However, little is known about how the daily oxidative stress of the skin is related to skin aging-related alterations in vivo. We characterized the steady state UPE and performed a skin survey. We evaluated the skin oxidative status by UPE, skin elasticity, epidermal thickness and skin color on the inner upper arm, the outer forearm, and the buttock of 70 Japanese volunteers. The steady state UPE at the three skin sites increased with age. Correlation analysis revealed that the steady state UPE only from the buttock was related to skin elasticity, which showed age-dependent changes. Moreover, analysis by age group indicated that b* values of the inner upper arm of subjects in their 20s were inversely correlated with UPE as occurred in buttock skin. In contrast, photoaged skin did not show a clear relationship with steady state UPE because the accumulation of sun-exposure might influence the sensitivity to oxidative stress. These results suggest that steady state UPE reflects not only intrinsic skin aging and cutaneous color but also the current oxidative status independent of skin aging. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Constraints on the Detection of the Solar Nebula's Oxidation State Through Asteroid Observations

NASA Technical Reports Server (NTRS)

Abell, P. A.; Gaffey, M. J.; Hardersen, P. S.

2005-01-01

Introduction: Asteroids represent the only in situ surviving population of planetesimals from the formation of the inner solar system and therefore include materials from the very earliest stages of solar system formation. Hence, these bodies can provide constraints on the processes and conditions that were present during this epoch and can be used to test current models and theories describing the late solar nebula, the early solar system and subsequent planetary accretion. From detailed knowledge of asteroid mineralogic compositions the probable starting materials, thermal histories, and oxidation states of asteroid parent bodies can be inferred. If such data can be obtained from specific mainbelt source regions, then this information can be used to map out the formation conditions of the late solar nebula within the inner solar system and possibly distinguish any trends in oxidation state that may be present.

Arsenic in ground-water under oxidizing conditions, south-west United States

USGS Publications Warehouse

Robertson, F.N.

1989-01-01

Concentrations of dissolved arsenic in ground-water in alluvial basins of Arizona commonly exceed 50 ??g L-1 and reach values as large as 1,300 ??g L-1. Arsenic speciation analyses show that arsenic occurs in the fully oxidized state of plus 5 (As+5), most likely in the form of HAsO4???2, under existing oxidizing and pH conditions. Arsenic in source areas presumably is oxidized to soluble As before transport into the basin or, if after transport, before burial. Probable sources of arsenic are the sulphide and arsenide deposits in the mineralized areas of the mountains surrounding the basins. Arsenic content of alluvial material ranged from 2 to 88 ppm. Occurrence and removal of arsenic in ground-water are related to the pH and the redox condition of the ground-water, the oxidation state of arsenic, and sorption or exchange. Within basins, dissolved arsenic correlates (P<0.01) with dissolved molybdenum, selenium, vanadium, and fluoride and with pH, suggesting sorption of negative ions. The sorption hypothesis is further supported by enrichment of teachable arsenic in the basin-fill sediments by about tenfold relative to the crustal abundance and by as much as a thousandfold relative to concentrations found in ground-water. Silicate hydrolysis reactions, as defined within the alluvial basins, under closed conditions cause increases in pH basinward and would promote desorption. Within the region, large concentrations of arsenic are commonly associated with the central parts of basins whose chemistries evolve under closed conditions. Arsenic does not correlate with dissolved iron (r = 0.09) but may be partly controlled by iron in the solid phase. High solid-phase arsenic contents were found in red clay beds. Large concentrations of arsenic also were found in water associated with red clay beds. Basins that contain the larger concentrations are bounded primarily by basalt and andesite, suggesting that the iron content as well as the arsenic content of the basin fill may

Cloud droplet activation through oxidation of organic aerosol influenced by temperature and particle phase state: CLOUD ACTIVATION BY AGED ORGANIC AEROSOL

DOE PAGES

Slade, Jonathan H.; Shiraiwa, Manabu; Arangio, Andrea; ...

2017-02-04

Chemical aging of organic aerosol (OA) through multiphase oxidation reactions can alter their cloud condensation nuclei (CCN) activity and hygroscopicity. However, the oxidation kinetics and OA reactivity depend strongly on the particle phase state, potentially influencing the hydrophobic-to-hydrophilic conversion rate of carbonaceous aerosol. Here, amorphous Suwannee River fulvic acid (SRFA) aerosol particles, a surrogate humic-like substance (HULIS) that contributes substantially to global OA mass, are oxidized by OH radicals at different temperatures and phase states. When oxidized at low temperature in a glassy solid state, the hygroscopicity of SRFA particles increased by almost a factor of two, whereas oxidation ofmore » liquid-like SRFA particles at higher temperatures did not affect CCN activity. Low-temperature oxidation appears to promote the formation of highly-oxygenated particle-bound fragmentation products with lower molar mass and greater CCN activity, underscoring the importance of chemical aging in the free troposphere and its influence on the CCN activity of OA.« less

Identification of ground-state spin ordering in antiferromagnetic transition metal oxides using the Ising model and a genetic algorithm

PubMed Central

Lee, Kyuhyun; Youn, Yong; Han, Seungwu

2017-01-01

Abstract We identify ground-state collinear spin ordering in various antiferromagnetic transition metal oxides by constructing the Ising model from first-principles results and applying a genetic algorithm to find its minimum energy state. The present method can correctly reproduce the ground state of well-known antiferromagnetic oxides such as NiO, Fe2O3, Cr2O3 and MnO2. Furthermore, we identify the ground-state spin ordering in more complicated materials such as Mn3O4 and CoCr2O4. PMID:28458746

Multicultural maternal and child health outreach: Washington State strategies to assure access for Asian and Pacific Islander women and children.

PubMed

Greenberg, E L; Perz, M; Sockalingam, S; Hayes, M

1996-01-01

This article outlines some of the barriers to health care experienced by Asian and Pacific Islander Communities. The authors then describe a number of strategies the Washington State Department of Health has used to reduce cultural and linguistic barriers to health care. As a state health agency, the Department has promoted accessible programs through mechanisms such as improved data collection, culturally competent staff, targeted outreach, and development of partnerships with community organizations and other agencies to promote culturally accessible health care delivery.

Cost-effective, transfer-free, flexible resistive random access memory using laser-scribed reduced graphene oxide patterning technology.

PubMed

Tian, He; Chen, Hong-Yu; Ren, Tian-Ling; Li, Cheng; Xue, Qing-Tang; Mohammad, Mohammad Ali; Wu, Can; Yang, Yi; Wong, H-S Philip

2014-06-11

Laser scribing is an attractive reduced graphene oxide (rGO) growth and patterning technology because the process is low-cost, time-efficient, transfer-free, and flexible. Various laser-scribed rGO (LSG) components such as capacitors, gas sensors, and strain sensors have been demonstrated. However, obstacles remain toward practical application of the technology where all the components of a system are fabricated using laser scribing. Memory components, if developed, will substantially broaden the application space of low-cost, flexible electronic systems. For the first time, a low-cost approach to fabricate resistive random access memory (ReRAM) using laser-scribed rGO as the bottom electrode is experimentally demonstrated. The one-step laser scribing technology allows transfer-free rGO synthesis directly on flexible substrates or non-flat substrates. Using this time-efficient laser-scribing technology, the patterning of a memory-array area up to 100 cm(2) can be completed in 25 min. Without requiring the photoresist coating for lithography, the surface of patterned rGO remains as clean as its pristine state. Ag/HfOx/LSG ReRAM using laser-scribing technology is fabricated in this work. Comprehensive electrical characteristics are presented including forming-free behavior, stable switching, reasonable reliability performance and potential for 2-bit storage per memory cell. The results suggest that laser-scribing technology can potentially produce more cost-effective and time-effective rGO-based circuits and systems for practical applications.

Electrochemical oxidation of 243Am(III) in nitric acid by a terpyridyl-derivatized electrode

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

Dares, C. J.; Lapides, A. M.; Mincher, B. J.

A high surface area, tin-doped indium oxide electrode surface-derivatized with a terpyridine ligand has been applied to the oxidation of trivalent americium to Am(V) and Am(VI) in nitric acid. Potentials as low as 1.8 V vs. the saturated calomel electrode are used, 0.7 V lower than the 2.6 V potential for one-electron oxidation of Am(III) to Am(IV) in 1 M acid. This simple electrochemical procedure provides, for the first time, a method for accessing the higher oxidation states of Am in non-complexing media for developing the coordination chemistries of Am(V) and Am(VI) and, more importantly, for separation of americium frommore » nuclear waste streams.« less

Active three-way catalysis of rhodium particles with a low oxidation state maintained under an oxidative atmosphere on a La-containing ZrO2 support.

PubMed

Kawabata, Hisaya; Koda, Yuki; Sumida, Hirosuke; Shigetsu, Masahiko; Takami, Akihide; Inumaru, Kei

2013-05-11

Rhodium on a La-containing ZrO2 support effectively eliminated NOx from a synthetic auto exhaust gas under fluctuating oxygen conditions. Rhodium particles maintained a low oxidation state on the ZrO2-La2O3 mixed oxide even after treatment with 5% O2 at 773 K, highlighting the significant effect of the La addition.

Forest soil carbon oxidation state and oxidative ratio responses to elevated CO 2

DOE PAGES

Hockaday, William C.; Gallagher, Morgan E.; Masiello, Caroline A.; ...

2015-09-21

The oxidative ratio (OR) of the biosphere is the stoichiometric ratio (O 2/CO 2) of gas exchange by photosynthesis and respiration a key parameter in budgeting calculations of the land and ocean carbon sinks. Carbon cycle-climate feedbacks could alter the OR of the biosphere by affecting the quantity and quality of organic matter in plant biomass and soil carbon pools. Here, this study considers the effect of elevated atmospheric carbon dioxide concentrations ([CO 2]) on the OR of a hardwood forest after nine growing seasons of Free-Air CO 2 Enrichment. We measured changes in the carbon oxidation state (C ox)more » of biomass and soil carbon pools as a proxy for the ecosystem OR. The OR of net primary production, 1.039, was not affected by elevated [CO 2]. However, the C ox of the soil carbon pool was 40% higher at elevated [CO 2], and the estimated OR values for soil respiration increased from 1.006 at ambient [CO 2] to 1.054 at elevated [CO 2]. A biochemical inventory of the soil organic matter ascribed the increases in C ox and OR to faster turnover of reduced substrates, lignin and lipids, at elevated [CO 2]. This implicates the heterotrophic soil community response to elevated [CO 2] as a driver of disequilibrium in the ecosystem OR. The oxidation of soil carbon pool constitutes an unexpected terrestrial O 2 sink. Carbon budgets constructed under the assumption of OR equilibrium would equate such a terrestrial O 2 sink to CO 2 uptake by the ocean. We find that the potential for climate-driven disequilibriua in the cycling of O 2 and CO 2 warrants further investigation.« less

Suicide Rates and State Laws Regulating Access and Exposure to Handguns

PubMed Central

Anestis, Joye C.

2015-01-01

Objectives. Using previous research, we examined the impact of 4 handgun laws (waiting periods, universal background checks, gun locks, and open carrying regulations) on suicide rates. Methods. We used publicly available databases to collect information on statewide laws, suicide rates, and demographic characteristics for 2013. Results. Each law was associated with significantly lower firearm suicide rates and the proportion of suicides resulting from firearms. In addition, each law, except for that which required a waiting period, was associated with a lower overall suicide rate. Follow-up analyses showed a significant indirect effect on overall suicide rates through the proportion of suicides by firearms, indicating that the reduced overall suicide rate was attributable to fewer suicide attempts, fewer handguns in the home, suicide attempts using less lethal means, or a combination of these factors. States that implemented any of these laws saw a decreased suicide rate in subsequent years, whereas the only state that repealed 1 of these laws saw an increased suicide rate. Conclusions. Our results were supportive of a potentially vital role in suicide prevention for state legislation that limits access and exposure to handguns. PMID:26270305

Visualizing different uranium oxidation states during the surface alteration of uraninite and uranium tetrachloride.

PubMed

Grossmann, Kay; Arnold, Thuro; Steudtner, Robin; Weiss, Stefan; Bernhard, Gert

2009-08-01

Low-temperature alteration reactions on uranium phases may lead to the mobilization of uranium and thereby poses a potential threat to humans living close to uranium-contaminated sites. In this study, the surface alteration of uraninite (UO(2)) and uranium tetrachloride (UCl(4)) in air atmosphere was studied by confocal laser scanning microscopy (CLSM) and laser-induced fluorescence spectroscopy using an excitation wavelength of 408 nm. It was found that within minutes the oxidation state on the surface of the uraninite and the uranium tetrachloride changed. During the surface alteration process U(IV) atoms on the uraninite and uranium tetrachloride surface became stepwise oxidized by a one-electron step at first to U(V) and then further to U(VI). These observed changes in the oxidation states of the uraninite surface were microscopically visualized and spectroscopically identified on the basis of their fluorescence emission signal. A fluorescence signal in the wavelength range of 415-475 nm was indicative for metastable uranium(V), and a fluorescence signal in the range of 480-560 nm was identified as uranium(VI). In addition, the oxidation process of tetravalent uranium in aqueous solution at pH 0.3 was visualized by CLSM and U(V) was fluorescence spectroscopically identified. The combination of microscopy and fluorescence spectroscopy provided a very convincing visualization of the brief presence of U(V) as a metastable reaction intermediate and of the simultaneous coexistence of the three states U(IV), U(V), and U(VI). These results have a significant importance for fundamental uranium redox chemistry and should contribute to a better understanding of the geochemical behavior of uranium in nature.

Transitions between strongly correlated and random steady-states for catalytic CO-oxidation on surfaces at high-pressure

DOE PAGES

Liu, Da -Jiang; Evans, James W.

2015-04-02

We explore simple lattice-gas reaction models for CO-oxidation on 1D and 2D periodic arrays of surface adsorption sites. The models are motivated by studies of CO-oxidation on RuO 2(110) at high-pressures. Although adspecies interactions are neglected, the effective absence of adspecies diffusion results in kinetically-induced spatial correlations. A transition occurs from a random mainly CO-populated steady-state at high CO-partial pressure p CO, to a strongly-correlated near-O-covered steady-state for low p CO as noted. In addition, we identify a second transition to a random near-O-covered steady-state at very low p CO.

Timeliness and access to healthcare services via telemedicine for adolescents in state correctional facilities.

PubMed

Fox, Karen C; Somes, Grant W; Waters, Teresa M

2007-08-01

The aim of this study was to examine the effectiveness of a telemedicine program in improving timeliness of and access to healthcare services in adolescent correctional facilities. This study is a pre/post quasi-experimental design comparing time to treatment and healthcare use in the year preceding and the 2 years after the implementation of a telemedicine program in four facilities housing adolescents from 12 to 19. Timeliness of care is measured by time from referral to date of service (for behavioral healthcare only). Access to care is measured by use of outpatient care, emergency department (ED) visits, and inpatient visits. Two of the four state correctional facilities had a significant decrease (24%) in time from referral to treatment after the implementation of the telemedicine intervention. The facilities not showing significant improvements in timeliness experienced difficulty implementing the telemedicine program. The telemedicine program was also associated with significant improvements in access to care. Outpatient visits increased by 40% in the 2 years after implementation of telemedicine. For each 1% increase in telemedicine usage, outpatient visits increased by 1%, whereas emergency room visits decreased by 7%. Telemedicine can have a positive impact on timeliness of and access to care for youth in correctional facilities.

Race/ethnicity and geographic access to Medicaid substance use disorder treatment facilities in the United States.

PubMed

Cummings, Janet R; Wen, Hefei; Ko, Michelle; Druss, Benjamin G

2014-02-01

Although substance use disorders (SUDs) are prevalent and associated with adverse consequences, treatment rates remain low. Unlike physical and mental health problems, treatment for SUDs is predominantly provided in a separate specialty sector and more heavily financed by public sources. Medicaid expansion under the Patient Protection and Affordable Care Act has the potential to increase access to treatment for SUDs but only if an infrastructure exists to serve new enrollees. To examine the availability of outpatient SUD treatment facilities that accept Medicaid across US counties and whether counties with a higher percentage of racial/ethnic minorities are more likely to have gaps in this infrastructure. We used data from the 2009 National Survey of Substance Abuse Treatment Services public use file and the 2011-2012 Area Resource file to examine sociodemographic factors associated with county-level access to SUD treatment facilities that serve Medicaid enrollees. Counties in all 50 states were included. We estimated a probit model with state indicators to adjust for state-level heterogeneity in demographics, politics, and policies. Independent variables assessed county racial/ethnic composition (ie, percentage black and percentage Hispanic), percentage living in poverty, percentage living in a rural area, percentage insured with Medicaid, percentage uninsured, and total population. Dichotomous indicator for counties with at least 1 outpatient SUD treatment facility that accepts Medicaid. Approximately 60% of US counties have at least 1 outpatient SUD facility that accepts Medicaid, although this rate is lower in many Southern and Midwestern states than in other areas of the country. Counties with a higher percentage of black (marginal effect [ME],  -3.1; 95% CI,  -5.2% to -0.9%), rural (-9.2%; -11.1% to -7.4%), and/or uninsured (-9.5%; -13.0% to -5.9%) residents are less likely to have one of these facilities. The potential for increasing access to SUD

Teaching the Properties of Chromium's Oxidation States with a Case Study Method

ERIC Educational Resources Information Center

Ozdilek, Zehra

2015-01-01

The purpose of this study was to investigate how a mixed-method case study affects pre-service science teachers' awareness of hexavalent chromium pollution and content knowledge about the properties of chromium's different oxidation states. The study was conducted in Turkey with 55 sophomores during the fall semester of 2013-2014. The students…

Influence of Thermal Annealing Treatment on Bipolar Switching Properties of Vanadium Oxide Thin-Film Resistance Random-Access Memory Devices

NASA Astrophysics Data System (ADS)

Chen, Kai-Huang; Cheng, Chien-Min; Kao, Ming-Cheng; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Wu, Sean; Su, Feng-Yi

2017-04-01

The bipolar switching properties and electrical conduction mechanism of vanadium oxide thin-film resistive random-access memory (RRAM) devices obtained using a rapid thermal annealing (RTA) process have been investigated in high-resistive status/low-resistive status (HRS/LRS) and are discussed herein. In addition, the resistance switching properties and quality improvement of the vanadium oxide thin-film RRAM devices were measured by x-ray diffraction (XRD) analysis, x-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and current-voltage ( I- V) measurements. The activation energy of the hopping conduction mechanism in the devices was investigated based on Arrhenius plots in HRS and LRS. The hopping conduction distance and activation energy barrier were obtained as 12 nm and 45 meV, respectively. The thermal annealing process is recognized as a candidate method for fabrication of thin-film RRAM devices, being compatible with integrated circuit technology for nonvolatile memory devices.

Molecular beam epitaxy growth of niobium oxides by solid/liquid state oxygen source and lithium assisted metal-halide chemistry

NASA Astrophysics Data System (ADS)

Tellekamp, M. Brooks; Greenlee, Jordan D.; Shank, Joshua C.; Doolittle, W. Alan

2015-09-01

In order to consistently grow high quality niobium oxides and lithium niobium oxides, a novel solid/liquid state oxygen source, LiClO4, has been implemented in a molecular beam epitaxy (MBE) system. LiClO4 is shown to decompose into both molecular and atomic oxygen upon heating. This allows oxidation rates similar to that of molecular oxygen but at a reduced overall beam flux, quantified by in situ Auger analysis. LiClO4 operation is decomposition limited to less than 400 °C, and other material limitations are identified. The design of a custom near-ambient NbCl5 effusion cell is presented, which improves both short and long term stability. Films of Nb oxidation state +2, +3, and +5 are grown using these new tools, including the multi-functional sub-oxide LiNbO2.

Real-time plasmon spectroscopy study of the solid-state oxidation and Kirkendall void formation in copper nanoparticles.

PubMed

Susman, Mariano D; Feldman, Yishai; Bendikov, Tatyana A; Vaskevich, Alexander; Rubinstein, Israel

2017-08-31

Oxidation and corrosion reactions have a major effect on the application of non-noble metals. Kinetic information and simple theoretical models are often insufficient for describing such processes in metals at the nanoscale, particularly in cases involving formation of internal voids (nano Kirkendall effect, NKE) during oxidation. Here we study the kinetics of solid-state oxidation of chemically-grown copper nanoparticles (NPs) by in situ localized surface plasmon resonance (LSPR) spectroscopy during isothermal annealing in the range 110-170 °C. We show that LSPR spectroscopy is highly effective in kinetic studies of such systems, enabling convenient in situ real-time measurements during oxidation. Change of the LSPR spectra throughout the oxidation follows a common pattern, observed for different temperatures, NP sizes and substrates. The well-defined initial Cu NP surface plasmon (SP) band red-shifts continuously with oxidation, while the extinction intensity initially increases to reach a maximum value at a characteristic oxidation time τ, after which the SP intensity continuously drops. The characteristic time τ is used as a scaling parameter for the kinetic analysis. Evolution of the SP wavelength and extinction intensity during oxidation at different temperatures follows the same kinetics when the oxidation time is normalized to τ, thus pointing to a general oxidation mechanism. The characteristic time τ is used to estimate the activation energy of the process, determined to be 144 ± 6 kJ mol -1 , similar to previously reported values for high-temperature Cu thermal oxidation. The central role of the NKE in the solid-state oxidation process is revealed by electron microscopy, while formation of Cu 2 O as the major oxidation product is established by X-ray diffraction, XPS, and electrochemical measurements. The results indicate a transition of the oxidation mechanism from a Valensi-Carter (VC) to NKE mechanism with the degree of oxidation. To interpret

The pervasive crisis of diminishing radiation therapy access for vulnerable populations in the United States, part 1: African-American patients.

PubMed

McClelland, Shearwood; Page, Brandi R; Jaboin, Jerry J; Chapman, Christina H; Deville, Curtiland; Thomas, Charles R

2017-01-01

African Americans experience the highest burden of cancer incidence and mortality in the United States and have been persistently less likely to receive interventional care, even when such care has been proven superior to conservative management by randomized controlled trials. The presence of disparities in access to radiation therapy (RT) for African American cancer patients has rarely been examined in an expansive fashion. An extensive literature search was performed using the PubMed database to examine studies investigating disparities in RT access for African Americans. A total of 55 studies were found, spanning 11 organ systems. Disparities in access to RT for African Americans were most prominently study in cancers of the breast (23 studies), prostate (7 studies), gynecologic system (5 studies), and hematologic system (5 studies). Disparities in RT access for African Americans were prevalent regardless of organ system studied and often occurred independently of socioeconomic status. Fifty of 55 studies (91%) involved analysis of a population-based database such as Surveillance, Epidemiology and End Result (SEER; 26 studies), SEER-Medicare (5 studies), National Cancer Database (3 studies), or a state tumor registry (13 studies). African Americans in the United States have diminished access to RT compared with Caucasian patients, independent of but often in concert with low socioeconomic status. These findings underscore the importance of finding systemic and systematic solutions to address these inequalities to reduce the barriers that patient race provides in receipt of optimal cancer care.

Short review of high-pressure crystal growth and magnetic and electrical properties of solid-state osmium oxides

NASA Astrophysics Data System (ADS)

Yamaura, Kazunari

2016-04-01

High-pressure crystal growth and synthesis of selected solid-state osmium oxides, many of which are perovskite-related types, are briefly reviewed, and their magnetic and electrical properties are introduced. Crystals of the osmium oxides, including NaOsO3, LiOsO3, and Na2OsO4, were successfully grown under high-pressure and high-temperature conditions at 6 GPa in the presence of an appropriate amount of flux in a belt-type apparatus. The unexpected discovery of a magnetic metal-insulator transition in NaOsO3, a ferroelectric-like transition in LiOsO3, and high-temperature ferrimagnetism driven by a local structural distortion in Ca2FeOsO6 may represent unique features of the osmium oxides. The high-pressure and high-temperature synthesis and crystal growth has played a central role in the development of solid-state osmium oxides and the elucidation of their magnetic and electronic properties toward possible use in multifunctional devices.

The oxidation state of Hadean magmas and implications for early Earth's atmosphere.

PubMed

Trail, Dustin; Watson, E Bruce; Tailby, Nicholas D

2011-11-30

Magmatic outgassing of volatiles from Earth's interior probably played a critical part in determining the composition of the earliest atmosphere, more than 4,000 million years (Myr) ago. Given an elemental inventory of hydrogen, carbon, nitrogen, oxygen and sulphur, the identity of molecular species in gaseous volcanic emanations depends critically on the pressure (fugacity) of oxygen. Reduced melts having oxygen fugacities close to that defined by the iron-wüstite buffer would yield volatile species such as CH(4), H(2), H(2)S, NH(3) and CO, whereas melts close to the fayalite-magnetite-quartz buffer would be similar to present-day conditions and would be dominated by H(2)O, CO(2), SO(2) and N(2) (refs 1-4). Direct constraints on the oxidation state of terrestrial magmas before 3,850 Myr before present (that is, the Hadean eon) are tenuous because the rock record is sparse or absent. Samples from this earliest period of Earth's history are limited to igneous detrital zircons that pre-date the known rock record, with ages approaching ∼4,400 Myr (refs 5-8). Here we report a redox-sensitive calibration to determine the oxidation state of Hadean magmatic melts that is based on the incorporation of cerium into zircon crystals. We find that the melts have average oxygen fugacities that are consistent with an oxidation state defined by the fayalite-magnetite-quartz buffer, similar to present-day conditions. Moreover, selected Hadean zircons (having chemical characteristics consistent with crystallization specifically from mantle-derived melts) suggest oxygen fugacities similar to those of Archaean and present-day mantle-derived lavas as early as ∼4,350 Myr before present. These results suggest that outgassing of Earth's interior later than ∼200 Myr into the history of Solar System formation would not have resulted in a reducing atmosphere.

Assigning Oxidation States to Organic Compounds via Predictions from X-Ray Photoelectron Spectroscopy: A Discussion of Approaches and Recommended Improvements

ERIC Educational Resources Information Center

Gupta, Vipul; Ganegoda, Hasitha; Engelhard, Mark H.; Terry, Jeff; Linford, Matthew R.

2014-01-01

The traditional assignment of oxidation states to organic molecules is problematic. Accordingly, in 1999, Calzaferri proposed a simple and elegant solution that is based on the similar electronegativities of carbon and hydrogen: hydrogen would be assigned an oxidation state of zero when bonded to carbon. Here, we show that X-ray photoelectron…

Child- and state-level characteristics associated with preventive dental care access among U.S. children 5-17 years of age.

PubMed

Lin, Mei; Sappenfield, William; Hernandez, Leticia; Clark, Cheryl; Liu, Jihong; Collins, Jennifer; Carle, Adam C

2012-12-01

The objectives of this study is to identify factors associated with lack of preventive dental care among U.S. children and state-level factors that explain variation in preventive dental care access across states. We performed bivariate analyses and multilevel regression analyses among 68,350 children aged 5-17 years using the 2007 National Survey of Children's Health data and relevant state-level data. Odds ratios (ORs) for child- and state-level variables were calculated to estimate associations with preventive dental care. We calculated interval odds ratios (IOR), median odds ratios (MOR), and intraclass correlation coefficients (ICC) to quantify variation in preventive dental care across states. Lack of preventive dental care was associated with various child-level factors. For state-level factors, a higher odds of lack of preventive dental care was associated with a higher percentage of Medicaid-enrolled children not receiving dental services (OR = 1.30, 95 % confidence interval (CI): 1.15-1.47); higher percentage of children uninsured (OR = 1.48, 95 % CI: 1.29-1.69); lower dentist-to-population ratio (OR = 1.36, 95 % CI: 1.03-1.80); and lower percentage of dentists submitting Medicaid/State Children's Health Insurance Program claims (OR = 1.04, 95 % CI: 1.01-1.06). IORs for the first three state-level factors did not contain one, indicating that these state-level characteristics were important in understanding variation across states. Lack of preventive dental care varied by state (MOR = 1.40). The state-level variation (ICC = 3.66 %) accounted for a small percentage of child- and state-level variation combined. Child- and state-level characteristics were associated with preventive dental care access among U.S. children aged 5-17 years. State-level factors contribute to variation in dental care access across states and need to be considered in state-level planning.

Doing State Policy at Preschool: An Autoethnographic Tale of Universal Access to ECEC in Australia

ERIC Educational Resources Information Center

Millei, Zsuzsa; Gobby, Brad; Gallagher, Jannelle

2017-01-01

In 2009, the Australian states and territories signed an agreement to provide 15 hours per week of universal access to quality early education to all children in Australia in the year before they enter school. Taking on board the international evidence about the importance of early education, the Commonwealth government made a considerable…

Accuracy and Precision in Measurements of Biomass Oxidative Ratio and Carbon Oxidation State

NASA Astrophysics Data System (ADS)

Gallagher, M. E.; Masiello, C. A.; Randerson, J. T.; Chadwick, O. A.; Robertson, G. P.

2007-12-01

Ecosystem oxidative ratio (OR) is a critical parameter in the apportionment of anthropogenic CO2 between the terrestrial biosphere and ocean carbon reservoirs. OR is the ratio of O2 to CO2 in gas exchange fluxes between the terrestrial biosphere and atmosphere. Ecosystem OR is linearly related to biomass carbon oxidation state (Cox), a fundamental property of the earth system describing the bonding environment of carbon in molecules. Cox can range from -4 to +4 (CH4 to CO2). Variations in both Cox and OR are driven by photosynthesis, respiration, and decomposition. We are developing several techniques to accurately measure variations in ecosystem Cox and OR; these include elemental analysis, bomb calorimetry, and 13C nuclear magnetic resonance spectroscopy. A previous study, comparing the accuracy and precision of elemental analysis versus bomb calorimetry for pure chemicals, showed that elemental analysis-based measurements are more accurate, while calorimetry- based measurements yield more precise data. However, the limited biochemical range of natural samples makes it possible that calorimetry may ultimately prove most accurate, as well as most cost-effective. Here we examine more closely the accuracy of Cox and OR values generated by calorimetry on a large set of natural biomass samples collected from the Kellogg Biological Station-Long Term Ecological Research (KBS-LTER) site in Michigan.

Correlation of the oxidation state of cerium in sol-gel glasses as a function of thermal treatment via optical spectroscopy and XANES studies.

PubMed

Assefa, Zerihun; Haire, R G; Caulder, D L; Shuh, D K

2004-07-01

Sol-gel glass matrices containing lanthanides have numerous technological applications and their formation involves several chemical facets. In the case of cerium, its ability to exist in two different oxidation states or in mixed valence state provides additional complexities for the sol-gel process. The oxidation state of cerium present during different facets of preparation of sol-gel glasses, and also as a function of the starting oxidation state of cerium added, were studied both by optical spectroscopy and X-ray absorption near-edge structures (XANES). The findings acquired by each approach were compared. The primary focus was on the redox chemistries associated with sample preparation, gelation, and thermal treatment. When Ce3+ is introduced into the starting sols, the trivalent state normally prevails in the wet and room temperature-dried gels. Heating in air at >100 degrees C can generate a light yellow coloration with partial oxidation to the tetravalent state. Above 200 degrees C and up to approximately 1000 degrees C, cerium is oxidized to its tetravalent state. In contrast, when tetravalent cerium is introduced into the sol, both the wet and room temperature-dried gels lose the yellow-brown color of the initial ceric ammonium nitrate solution. When the sol-gel is heated to 110 degrees C it turns yellowish as the cerium tends to be re-oxidized. The yellow color is believed to represent the effect of oxidation and oligomerization of the cerium-silanol units in the matrix. The luminescence properties are also affected by these changes, the details of which are reported herein.

Exploratory Characterization of Phenolic Compounds with Demonstrated Anti-Diabetic Activity in Guava Leaves at Different Oxidation States

PubMed Central

Díaz-de-Cerio, Elixabet; Verardo, Vito; Gómez-Caravaca, Ana María; Fernández-Gutiérrez, Alberto; Segura-Carretero, Antonio

2016-01-01

Psidium guajava L. is widely used like food and in folk medicine all around the world. Many studies have demonstrated that guava leaves have anti-hyperglycemic and anti-hyperlipidemic activities, among others, and that these activities belong mainly to phenolic compounds, although it is known that phenolic composition in guava tree varies throughout seasonal changes. Andalusia is one of the regions in Europe where guava is grown, thus, the aim of this work was to study the phenolic compounds present in Andalusian guava leaves at different oxidation states (low, medium, and high). The phenolic compounds in guava leaves were determined by HPLC-DAD-ESI-QTOF-MS. The results obtained by chromatographic analysis reported that guava leaves with low degree of oxidation had a higher content of flavonols, gallic, and ellagic derivatives compared to the other two guava leaf samples. Contrary, high oxidation state guava leaves reported the highest content of cyanidin-glucoside that was 2.6 and 15 times higher than guava leaves with medium and low oxidation state, respectively. The QTOF platform permitted the determination of several phenolic compounds with anti-diabetic properties and provided new information about guava leaf phenolic composition that could be useful for nutraceutical production. PMID:27187352

Exploratory Characterization of Phenolic Compounds with Demonstrated Anti-Diabetic Activity in Guava Leaves at Different Oxidation States.

PubMed

Díaz-de-Cerio, Elixabet; Verardo, Vito; Gómez-Caravaca, Ana María; Fernández-Gutiérrez, Alberto; Segura-Carretero, Antonio

2016-05-11

Psidium guajava L. is widely used like food and in folk medicine all around the world. Many studies have demonstrated that guava leaves have anti-hyperglycemic and anti-hyperlipidemic activities, among others, and that these activities belong mainly to phenolic compounds, although it is known that phenolic composition in guava tree varies throughout seasonal changes. Andalusia is one of the regions in Europe where guava is grown, thus, the aim of this work was to study the phenolic compounds present in Andalusian guava leaves at different oxidation states (low, medium, and high). The phenolic compounds in guava leaves were determined by HPLC-DAD-ESI-QTOF-MS. The results obtained by chromatographic analysis reported that guava leaves with low degree of oxidation had a higher content of flavonols, gallic, and ellagic derivatives compared to the other two guava leaf samples. Contrary, high oxidation state guava leaves reported the highest content of cyanidin-glucoside that was 2.6 and 15 times higher than guava leaves with medium and low oxidation state, respectively. The QTOF platform permitted the determination of several phenolic compounds with anti-diabetic properties and provided new information about guava leaf phenolic composition that could be useful for nutraceutical production.

Enhanced photothermal effect in reduced graphene oxide in solid-state

NASA Astrophysics Data System (ADS)

Sahadev, Nishaina; Anappara, Aji A.

2017-11-01

We report on a giant photothermal effect in few-layer Reduced Graphene Oxide (RGO) in powder form. Graphite oxide synthesized following modified Hummer's method was thermally exfoliated and reduced to obtain RGO consisting of ˜8-10 layers. Upon irradiation with an incoherent, broad-band light source (wavelengths ranging from 250 to 450 nm), an enormous photothermal effect was observed. The heat generated by RGO determined from the isothermal differential photocalorimetric technique is as high as ˜319 W/g resulting from the dominant non-radiative de-excitation of photoexcited electrons due to the absence of a radiative pathway. A practical applicability was demonstrated using a commercial thermoelectric generator wherein upon illumination from a solar-simulator, an open voltage in the mV range was developed, giving a direct proof of the exothermic effect in powder RGO upon light illumination. Herewith, we have demonstrated a proof-of-concept of photothermal effects in solid-state RGO.

The Effects of a State Need-based Access Grant on Traditional and Nontraditional Student Persistence

ERIC Educational Resources Information Center

Davidson, J. Cody

2015-01-01

In 2011-2012, more than 236.7 billion dollars of student financial aid was disbursed to undergraduate and graduate students at postsecondary institutions in the United States. Today, many groups and organizations are advocating for financial aid to increase student access and success as well as to assist the neediest students. The purpose of this…

L-Edge Xanes Measurements of the Oxidation State of Tungsten in Iron Bearing and Iron Free Silicate Glasses

NASA Technical Reports Server (NTRS)

Danielson, L. R.; Righter, K.; Sutton, S.; Newville, M.

2008-01-01

Tungsten is important in constraining core formation of the Earth because this element is a moderately siderophile element (depleted 10 relative to chondrites) and, as a member of the Hf-W isotopic system, it is useful in constraining the timing of core formation. A number of previous experimental studies have been carried out to determine the silicate solubility and metal-silicate partitioning behavior of W, including its concomitant oxidation state. However, results of previous studies are inconsistent on whether W occurs as W(4+) or W(6+). It is assumed that W(4+) is the cation valence relevant to core formation. Given the sensitivity to silicate composition of high valence cations, knowledge of the oxidation state of W over a wide range of fO2 is critical to understanding the oxidation state of the mantle and core formation processes. This study seeks to measure the W valence and change in valence state over the range of fO2 most relevant to core formation, around IW-2.

Effect of valence state and particle size on NO oxidation in fresh and aged Pt-based diesel oxidation catalysts

NASA Astrophysics Data System (ADS)

Liang, Yanli; Ding, Xinmei; Zhao, Ming; Wang, Jianli; Chen, Yaoqiang

2018-06-01

To stabilize Pt, Magnesium-modified SiO2-Al2O3 materials was used to impregnate with Pt, which could strengthen the bonding effect between Pt and Mg. Before and after aging, both showed a higher dispersion. High valence state of Pt in fresh modified catalyst was unfavorable of NO oxidation, indicating that the valence state of Pt was the leader factor in fresh catalytic performance. While for the aged Mg-modified sample, its reaction temperature of 30% NO conversion lowered by around 30 °C. The Pt stabilization via interacting with Mg derives a relation that the variation of Pt valence state and its exposed sites played a significant role in fresh and aged catalytic NO activity, respectively.

Healthcare access and mobility between the UK and other European Union states: an 'implementation surplus'.

PubMed

Sheaff, R

1997-12-01

European Union (EU) policy on mobility requires ensuring healthcare access for EU residents who travel between EU states. This case-study investigates how this policy has been implemented in respect of EU visitors to the UK. EU visitors to the UK have similar access to 'immediately needed' National Health Service (NHS) healthcare to UK residents. For non-urgent healthcare, the NHS has official systems to discourage 'medical tourism' and divert such patients to the private sector or to reclaim the costs of NHS hospital treatment for EU visitors. Yet these official systems contrast with the flexibility and liberality of actual NHS practice towards EU visitors. Research on health policy implementation mostly examines reasons for 'implementation failure'. However, the present study indicates a health policy being implemented more fully than policy-makers may have anticipated. In the case of healthcare access for EU visitors to the UK, an implementation surplus is evident rather than an implementation deficit.

The Behavior of the Ru-bda Water Oxidation Catalysts at Low Oxidation States.

PubMed

Matheu, Roc; Ghaderian, Abolfazl; Francas, Laia; Chernev, Petko; Ertem, Mehmed; Benet-Buchholz, Jordi; Batista, Victor; Haumann, Michael; Gimbert-Suriñach, Carolina; Sala, Xavier; Llobet, Antoni

2018-06-13

The Ru complex [RuII(bda-κ-N2O2)(N-NH2)2], 1, (bda2- = (2,2'-bipyridine)-6,6'-dicarboxylate; N-NH2 = 4-(pyridin-4-yl)aniline) is used as a synthetic intermediate to prepare Ru-bda complexes that contain the NO+, acetonitrile (MeCN) or H2O ligands at oxidation states II and III. Complex 1 reacts with excess NO+ to form a Ru complex where the aryl amine ligands N-NH2 in 1 are transformed into diazonium salts (N-N2+ = 4-(pyridin-4-yl)benzenediazonium)) together with the formation of a new Ru-NO group at the equatorial zone, to generate [RuII(bda-κ-N2O)(NO)(N-N2)2]3+, 23+. Similarly, complex 1 can also react with a coordinating solvent, such as MeCN, at room temperature leading to complex [RuII(bda-κ-N2O)(MeCN)(N-NH2)2], 3. Finally in acidic aqueous solutions solvent water coordinates the Ru center forming {[RuII(bda-κ-(NO)3)(H2O)(N-NH3)2](H2O)n}2+, 42+, that is strongly hydrogen bonded with additional water molecules at the second coordination sphere. We have additionally characterized the one electron oxidized complex {[RuIII(bda-κ-(NO)3.5)(H2O)(N-NH3)2](H2O)n}3+, 53+. The coordination mode of the complexes has been studied both in the solid state and in solution through single-crystal XRD, X-ray absorption spectroscopy, variable-temperature NMR and DFT calculations. While the κ-N2O is the main coordination mode for 23+ and 3, an equilibrium that involves isomers with κ-N2O and κ-NO2 coordination modes and neighboring hydrogen bonded water molecules is observed for 42+ and 53+. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Youth access to tobacco.

PubMed

Rigotti, N A

1999-01-01

To start smoking, young people need a supply of tobacco products. Reducing youth access to tobacco is a new approach to preventing tobacco use that has been a focus of federal, state, and local tobacco control efforts over the past decade. All 50 states ban tobacco sales to minors, but compliance is poor because laws are not enforced. Consequently, young people have little trouble obtaining tobacco products. Commercial sources of tobacco (stores and vending machines) are important for underage smokers, who often purchase their own cigarettes. Underage youths also obtain tobacco from noncommercial sources such as friends, relatives, older adolescents, and adults. Educating retailers about tobacco sales laws has not produced long-term improvement in their compliance. Active enforcement of tobacco sales laws changes retailer behavior, but whether this reduces young people's access to tobacco or their tobacco use is not clear. The effectiveness of new local, state, and federal actions that aim to reduce youth access to tobacco remains to be determined. Can enforcing tobacco sales laws reduce young people's access to tobacco? If so, will this prevent or delay the onset of their tobacco use? How will youths' sources of tobacco change as commercial sources are restricted? What are the social (noncommercial) sources of tobacco for minors and how can youths' access to tobacco from these sources be reduced? What is the impact of the new federal policies aimed at reducing youth access to tobacco? Do new state and local laws that ban youth possession or use of tobacco have a net positive or negative impact on youth attitudes, access to tobacco, or tobacco use? What is the relative effectiveness and cost-effectiveness of efforts to reduce the supply of tobacco compared to those that aim to reduce demand for tobacco? Will either work alone or are both necessary to achieve reductions in youth smoking?

Limited school drinking water access for youth

PubMed Central

Kenney, Erica L.; Gortmaker, Steven L.; Cohen, Juliana F.W.; Rimm, Eric B.; Cradock, Angie L.

2016-01-01

PURPOSE Providing children and youth with safe, adequate drinking water access during school is essential for health. This study utilized objectively measured data to investigate the extent to which schools provide drinking water access that meets state and federal policies. METHODS We visited 59 middle and high schools in Massachusetts during spring 2012. Trained research assistants documented the type, location, and working condition of all water access points throughout each school building using a standard protocol. School food service directors (FSDs) completed surveys reporting water access in cafeterias. We evaluated school compliance with state plumbing codes and federal regulations and compared FSD self-reports of water access with direct observation; data were analyzed in 2014. RESULTS On average, each school had 1.5 (SD: 0.6) water sources per 75 students; 82% (SD: 20) were functioning, and fewer (70%) were both clean and functioning. Less than half of the schools met the federal Healthy Hunger Free Kids Act requirement for free water access during lunch; 18 schools (31%) provided bottled water for purchase but no free water. Slightly over half (59%) met the Massachusetts state plumbing code. FSDs overestimated free drinking water access compared to direct observation (96% FSD-reported versus 48% observed, kappa=0.07, p=0.17). CONCLUSIONS School drinking water access may be limited. In this study, many schools did not meet state or federal policies for minimum student drinking water access. School administrative staff may not accurately report water access. Public health action is needed to increase school drinking water access. IMPLICATIONS AND CONTRIBUTIONS Adolescents’ water consumption is lower than recommended. In a sample of Massachusetts middle and high schools, about half did not meet federal and state minimum drinking water access policies. Direct observation may improve assessments of drinking water access and could be integrated into routine

Silver(II) Oxide or Silver(I,III) Oxide?

ERIC Educational Resources Information Center

Tudela, David

2008-01-01

The often called silver peroxide and silver(II) oxide, AgO or Ag[subscript 2]O[subscript 2], is actually a mixed oxidation state silver(I,III) oxide. A thermochemical cycle, with lattice energies calculated within the "volume-based" thermodynamic approach, explain why the silver(I,III) oxide is more stable than the hypothetical silver(II) oxide.…

Access to care in the Baltic States: did crisis have an impact?

PubMed

Karanikolos, Marina; Gordeev, Vladimir S; Mackenbach, Johan P; McKee, Martin

2016-04-01

In 2009, brief but deep economic crisis profoundly affected the three Baltic States: Estonia, Latvia and Lithuania. In response, all three countries adopted severe austerity measures with the shared goal of containing rising deficits, but employing different methods. In this article, we analyze the impact of the economic crisis and post-crisis austerity measures on health systems and access to medical services in the three countries. We use the EU-SILC data to analyze trends in unmet medical need in 2005-2012, and apply log-binomial regression to calculate the risk of unmet medical need in the pre- and post- crisis period. Between 2009 and 2012 unmet need has increased significantly in Latvia (OR: 1.24, 95% confidence interval (CI): 1.15-1.34) and Estonia (OR: 1.98, 95% CI: 1.72-2.27), but not Lithuania (OR: 0.84. 95% CI: 0.69-1.04). The main drivers of increased unmet need were inability to afford care in Latvia and long waiting lists in Estonia. The impact of the crisis on access to care in the three countries varied, as did the austerity measures affecting their health systems. Estonia and Latvia experienced worsening access to care, largely exacerbating already existing barriers. The example of Lithuania suggests that deterioration in access is not inevitable, once health policies prioritise maintenance and availability of existing services, or if there is room for reducing existing inefficiencies. Moreover, better financial preparedness of health systems in Estonia and Lithuania achieved some protection of the population from increasing unmet need due to the rising cost of medical care. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Reframing Vulnerability: Mozambican Refugees’ Access to State-Funded Pensions in Rural South Africa

PubMed Central

2012-01-01

Researchers at the South African Medical Research Council/University of the Witwatersrand Rural Public Health and Health Transitions Research Unit (Agincourt) fieldsite in rural South Africa consider Mozambican residents more vulnerable than others in the local population. These self-settled refugees, many of whom are still not South African citizens, primarily came to South Africa in the 1980s during the Mozambican Civil War. This perceived economic vulnerability is rooted in their difficulties in accessing social grants, until recently legally available only to those with South African citizenship documentation. This paper focuses on semi-structured interviews with 30 ‘older’ women of Mozambican-descent living in the Agincourt area. These interviews highlight three important aspects of vulnerability; the respondents: (1) perceive a risk of deportation despite their having lived in the country for 20 years, (2) are unable to easily access social grants, namely the state-funded old-age pension, and (3) struggle to make ends meet when faced with daily needs and crisis situations. All three of these vulnerabilities were mediated to some extent by these women’s resourcefulness. They generated ties to South Africa through obtaining identification-documents, used these documents to access pensions, and used the pensions to help them sustain their multigenerational households. PMID:19142721

Reversible double oxidation and protonation of the non-innocent bridge in a nickel(II) salophen complex.

PubMed

de Bellefeuille, David; Askari, Mohammad S; Lassalle-Kaiser, Benedikt; Journaux, Yves; Aukauloo, Ally; Orio, Maylis; Thomas, Fabrice; Ottenwaelder, Xavier

2012-12-03

Substitution on the aromatic bridge of a nickel(II) salophen complex with electron-donating dimethylamino substituents creates a ligand with three stable, easily and reversibly accessible oxidation states. The one-electron-oxidized product is characterized as a nickel(II) radical complex with the radical bore by the central substituted aromatic ring, in contrast to other nickel(II) salen or salophen complexes that oxidize on the phenolate moieties. The doubly oxidized product, a singlet species, is best described as having an iminobenzoquinone bridge with a vinylogous distribution of bond lengths between the dimethylamino substituents. Protonation of the dimethylamino substituents inhibits these redox processes on the time scale of cyclovoltammetry, but electrolysis and chemical oxidation are consistent with deprotonation occurring concomitantly with electron transfer to yield the mono- and dioxidized species described above.

Interface states and internal photoemission in p-type GaAs metal-oxide-semiconductor surfaces

NASA Technical Reports Server (NTRS)

Kashkarov, P. K.; Kazior, T. E.; Lagowski, J.; Gatos, H. C.

1983-01-01

An interface photodischarge study of p-type GaAs metal-oxide-semiconductor (MOS) structures revealed the presence of deep interface states and shallow donors and acceptors which were previously observed in n-type GaAs MOS through sub-band-gap photoionization transitions. For higher photon energies, internal photoemission was observed, i.e., injection of electrons to the conduction band of the oxide from either the metal (Au) or from the GaAs valence band; the threshold energies were found to be 3.25 and 3.7 + or - 0.1 eV, respectively. The measured photoemission current exhibited a thermal activation energy of about 0.06 eV, which is consistent with a hopping mechanism of electron transport in the oxide.

Reduction-oxidation state and protein degradation in skeletal muscle of fasted and refed rats

NASA Technical Reports Server (NTRS)

Fagan, Julie M.; Tischler, Marc E.

1986-01-01

Redox state and protein degradation were measured in isolated muscles of fasted (up to 10 d) and refed (up to 4 d) 7- to 14-wk-old rats. Protein degradation in the extensor digitorum longus muscle, but not in the soleus muscle, was greater in the fasted rats than in weight-matched muscle from fed rats. The NAD couple was more oxidized in incubated and fresh extensor digitorum longus muscles and in some incubated soleus muscles of fasted rats than in weight-matched muscle from fed rats. In the extensor digitorum longus muscle of refed or prolonged fasted rats, protein degradation was slower and the NAD couple was more reduced than in the fed state. Therefore, oxidation of the NAD couple was associated with increased muscle breakdown during fasting, whereas reduction of the NAD couple was associated with muscle conservation and deposition.

Triplet-State Dissolved Organic Matter Quantum Yields and Lifetimes from Direct Observation of Aromatic Amine Oxidation.

PubMed

Schmitt, Markus; Erickson, Paul R; McNeill, Kristopher

2017-11-21

Excited triplet state chromophoric dissolved organic matter ( 3 CDOM*) is a short-lived mixture of excited-state species that plays important roles in aquatic photochemical processes. Unlike the study of the triplet states of well-defined molecules, which are amenable to transient absorbance spectroscopy, the study of 3 CDOM* is hampered by it being a complex mixture and its low average intersystem crossing quantum yield (Φ ISC ). This study is an alternative approach to investigating 3 CDOM* using transient absorption laser spectroscopy. The radical cation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), formed through oxidation by 3 CDOM*, was directly observable by transient absorption spectroscopy and was used to probe basic photophysical properties of 3 CDOM*. Quenching and control experiments verified that TMPD •+ was formed from 3 CDOM* under anoxic conditions. Model triplet sensitizers with a wide range of excited triplet state reduction potentials and CDOM oxidized TMPD at near diffusion-controlled rates. This gives support to the idea that a large cross-section of 3 CDOM* moieties are able to oxidize TMPD and that the complex mixture of 3 CDOM* can be simplified to a single signal. Using the TMPD •+ transient, the natural triplet lifetime and Φ ISC for different DOM isolates and natural waters were quantified; values ranged from 12 to 26 μs and 4.1-7.8%, respectively.

42 CFR 457.495 - State assurance of access to care and procedures to assure quality and appropriateness of care.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 4 2013-10-01 2013-10-01 false State assurance of access to care and procedures to assure quality and appropriateness of care. 457.495 Section 457.495 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STATE CHILDREN'S HEALTH INSURANCE...

42 CFR 457.495 - State assurance of access to care and procedures to assure quality and appropriateness of care.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 4 2014-10-01 2014-10-01 false State assurance of access to care and procedures to assure quality and appropriateness of care. 457.495 Section 457.495 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STATE CHILDREN'S HEALTH INSURANCE...

42 CFR 457.495 - State assurance of access to care and procedures to assure quality and appropriateness of care.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 4 2012-10-01 2012-10-01 false State assurance of access to care and procedures to assure quality and appropriateness of care. 457.495 Section 457.495 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STATE CHILDREN'S HEALTH INSURANCE...

42 CFR 457.495 - State assurance of access to care and procedures to assure quality and appropriateness of care.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false State assurance of access to care and procedures to assure quality and appropriateness of care. 457.495 Section 457.495 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STATE CHILDREN'S HEALTH INSURANCE...

42 CFR 457.495 - State assurance of access to care and procedures to assure quality and appropriateness of care.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 4 2011-10-01 2011-10-01 false State assurance of access to care and procedures to assure quality and appropriateness of care. 457.495 Section 457.495 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STATE CHILDREN'S HEALTH INSURANCE...

Probing ground-state hole transfer between equivalent, electrochemically inaccessible states in multiporphyrin arrays using time-resolved optical spectroscopy.

PubMed

Song, Hee-eun; Taniguchi, Masahiko; Kirmaier, Christine; Bocian, David F; Lindsey, Jonathan S; Holten, Dewey

2009-01-01

A new strategy is described and implemented for determining the rates of hole-transfer between equivalent porphyrins in multiporphyrin architectures. The approach allows access to these rates between sites that are not the most easily oxidized components of the array. The specific architectures investigated with this new strategy are triads consisting of one zinc porphyrin (Zn) and two free base porphyrins (Fb). The triads employ a diphenylethyne linker (ZnFbFbU) and a phenylene linker (ZnFbFbPhi). The zinc porphyrin is selectively oxidized to produce Zn(+)FbFb, the free base porphyrins are excited to produce the excited-state mixture Zn(+)Fb*Fb and Zn(+)FbFb*, and the subsequent dynamics are monitored by ultrafast absorption spectroscopy. The system evolves by a combination of energy- and hole-transfer processes involving (adjacent and nonadjacent) zinc and free base porphyrin constituents that are complete within 100 ps of excitation; the rate constants of many of these processes are derived from prior studies of the oxidized forms of the benchmark dyads (ZnFbU and ZnFbPhi). One of the excited-state decay channels produces the metastable state ZnFbFb(+) that decays to a second metastable state ZnFb(+)Fb by the target hole-transfer process, followed by rapid hole transfer to produce the Zn(+)FbFb thermodynamic ground state of the system. The rate constant for hole transfer between the free base porphyrins in the oxidized ZnFbFb triads is found to be (0.5 ns)(-1) and (0.6 ns)(-1) across phenylene and diphenylethyne linkers, respectively. These rate constants are comparable to those recently measured, using a related but distinct strategy, for ground-state hole transfer between zinc porphyrins in oxidized ZnZnFb triads. The two complementary strategies provide unique approaches for probing hole transfer between equivalent sites in multiporphyrin arrays, with the choice of method being guided by the particular target process and the ease of synthesis of the necessary

The influence of hydrogenation and oxygen vacancies on molybdenum oxides work function and gap states for application in organic optoelectronics.

PubMed

Vasilopoulou, Maria; Douvas, Antonios M; Georgiadou, Dimitra G; Palilis, Leonidas C; Kennou, Stella; Sygellou, Labrini; Soultati, Anastasia; Kostis, Ioannis; Papadimitropoulos, Giorgos; Davazoglou, Dimitris; Argitis, Panagiotis

2012-10-03

Molybdenum oxide is used as a low-resistance anode interfacial layer in applications such as organic light emitting diodes and organic photovoltaics. However, little is known about the correlation between its stoichiometry and electronic properties, such as work function and occupied gap states. In addition, despite the fact that the knowledge of the exact oxide stoichiometry is of paramount importance, few studies have appeared in the literature discussing how this stoichiometry can be controlled to permit the desirable modification of the oxide's electronic structure. This work aims to investigate the beneficial role of hydrogenation (the incorporation of hydrogen within the oxide lattice) versus oxygen vacancy formation in tuning the electronic structure of molybdenum oxides while maintaining their high work function. A large improvement in the operational characteristics of both polymer light emitting devices and bulk heterojunction solar cells incorporating hydrogenated Mo oxides as hole injection/extraction layers was achieved as a result of favorable energy level alignment at the metal oxide/organic interface and enhanced charge transport through the formation of a large density of gap states near the Fermi level.

Promoting healthy food consumption: a review of state-level policies to improve access to fruits and vegetables.

PubMed

Hood, Carlyn; Martinez-Donate, Ana; Meinen, Amy

2012-12-01

Research indicates poor nutrition is a leading determinant of the development of chronic disease, and increasing fruit and vegetable consumption is one method for decreasing obesity. Many policies have focused on increasing the demand for fruits and vegetables through price reductions and coupons. However, without ensuring a stable supply, increased demand can continue to raise prices, crowding out individuals who may otherwise have purchased fruits and vegetables and ultimately leading to continued disparities in access. This paper presents a review of selected state-level policy options recently proposed or implemented in states across the United States, and provides an evidence-based lens through which food access policy can be shaped in the Midwest. This review and potential framework uses Wisconsin to illustrate the feasibility of different state-level decisions and their potential impact on particular populations. Future supply-side policies to consider include expanding Electronic Benefit Transfer to the Special Supplemental Nutrition Program for Women, Infants and Children (WIC),program and farmers markets, incentivizing the purchase of locally grown produce, assisting local specialty farmers directly, and/or establishing a state-level food policy council. This review reveals that a food policy council would create a more sustainable policy analysis process to better ensure future policy adoption is truly comprehensive, encompassing the production, distribution and purchase of locally grown fruits and vegetables.

Surveillance for Health Care Access and Health Services Use, Adults Aged 18-64 Years - Behavioral Risk Factor Surveillance System, United States, 2014.

PubMed

Okoro, Catherine A; Zhao, Guixiang; Fox, Jared B; Eke, Paul I; Greenlund, Kurt J; Town, Machell

2017-02-24

As a result of the 2010 Patient Protection and Affordable Care Act, millions of U.S. adults attained health insurance coverage. However, millions of adults remain uninsured or underinsured. Compared with adults without barriers to health care, adults who lack health insurance coverage, have coverage gaps, or skip or delay care because of limited personal finances might face increased risk for poor physical and mental health and premature mortality. 2014. The Behavioral Risk Factor Surveillance System (BRFSS) is an ongoing, state-based, landline- and cellular-telephone survey of noninstitutionalized adults aged ≥18 years residing in the United States. Data are collected from states, the District of Columbia, and participating U.S. territories on health risk behaviors, chronic health conditions, health care access, and use of clinical preventive services (CPS). An optional Health Care Access module was included in the 2014 BRFSS. This report summarizes 2014 BRFSS data from all 50 states and the District of Columbia on health care access and use of selected CPS recommended by the U.S. Preventive Services Task Force or the Advisory Committee on Immunization Practices among working-aged adults (aged 18-64 years), by state, state Medicaid expansion status, expanded geographic region, and federal poverty level (FPL). This report also provides analysis of primary type of health insurance coverage at the time of interview, continuity of health insurance coverage during the preceding 12 months, and other health care access measures (i.e., unmet health care need because of cost, unmet prescription need because of cost, medical debt [medical bills being paid off over time], number of health care visits during the preceding year, and satisfaction with received health care) from 43 states that included questions from the optional BRFSS Health Care Access module. In 2014, health insurance coverage and other health care access measures varied substantially by state, state

The redox state of endogenous pyridine nucleotides can determine both the degree of mitochondrial oxidative stress and the solute selectivity of the permeability transition pore.

PubMed

Zago, E B; Castilho, R F; Vercesi, A E

2000-07-28

Acetoacetate, an NADH oxidant, stimulated the ruthenium red-insensitive rat liver mitochondrial Ca(2+) efflux without significant release of state-4 respiration, disruption of membrane potential (Deltapsi) or mitochondrial swelling. This process is compatible with the opening of the currently designated low conductance state of the permeability transition pore (PTP) and, under our experimental conditions, was associated with a partial oxidation of the mitochondrial pyridine nucleotides. In contrast, diamide, a thiol oxidant, induced a fast mitochondrial Ca(2+) efflux associated with a release of state-4 respiration, a disruption of Deltapsi and a large amplitude mitochondrial swelling. This is compatible with the opening of the high conductance state of the PTP and was associated with extensive oxidation of pyridine nucleotides. Interestingly, the addition of carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone to the acetoacetate experiment promoted a fast shift from the low to the high conductance state of the PTP. Both acetoacetate and diamide-induced mitochondrial permeabilization were inhibited by exogenous catalase. We propose that the shift from a low to a high conductance state of the PTP can be promoted by the oxidation of NADPH. This impairs the antioxidant function of the glutathione reductase/peroxidase system, strongly strengthening the state of mitochondrial oxidative stress.

Urbanization and Access Inequality to Collective Consumption Goods & Services related to Sanitation & Solid Waste in the cities of Sao Paulo State, Brazil

NASA Astrophysics Data System (ADS)

Roig, C. D. A.; Feitosa, F. D. F.; Monteiro, A. M. V.

2016-12-01

Cities are mainly a product of collective consumption and there is a pressing need to expand and deepen the discussion about the quality of access to collective goods and services in the urban world: the availability of electricity and potable water and its interrelation with the lack of solid waste management and wastewater treatment leading to pollution of water sources.This study attempts to measure urban stratification through access conditions to collective goods in the metropolitan regions of Sao Paulo State (SPS) by contributing with a research method that incorporates collective consumption as a core component of the population-environment relationship. The use of spatial analysis allows the examination of the structure and distribution of accessibility to sanitation services and basic urban infrastructure.The water stress situation in SPS is dramatic. The average water loss within these distribution systems is 34,3% and a 39% average sewage treatment rate of all wastewater generated. The SPS also imports 60,6% of electricity from other states that use mostly hydroelectric power which imposes greater pressure on the country's water resources. The energy and water crisis has harmed a number of essential rights related mostly to resource access and service continuity as suburban residents of poor municipalities are the ones most affected by disruptions.SPS is the most populous state of Brazil and this region of study is responsible for 75% of total State population with 83% of State GDP. There has been a major increase in water use conflicts such as power generation, urban water supply (including the Rio de Janeiro water demand) and the dilution of urban sewage and solid waste disposal. These collective consumption access problems demonstrate the urgent need for better integrated metropolitan management of natural resources and the urban commons.

Post-translational Regulation of Neuronal Nitric Oxide Synthase: Implications for sympatho-excitatory states

PubMed Central

Sharma, Neeru M; Patel, Kaushik P

2017-01-01

Introduction Nitric oxide (NO) synthesized via neuronal nitric oxide synthase (nNOS) plays a significant role in regulation/modulation of autonomic control of circulation. Various pathological states are associated with diminished nNOS expression and blunted autonomic effects of NO in the central nervous system (CNS) including heart failure, hypertension, diabetes mellitus, chronic renal failure etc. Therefore, elucidation of the molecular mechanism/s involved in dysregulation of nNOS is essential to understand the pathogenesis of increased sympathoexcitation in these diseased states. Areas Covered nNOS is a highly regulated enzyme, being regulated at transcriptional and posttranslational levels via protein-protein interactions and modifications viz. phosphorylation, ubiquitination, and sumoylation. The enzyme activity of nNOS also depends on the optimal concentration of substrate, cofactors and association with regulatory proteins. This review focuses on the posttranslational regulation of nNOS in the context of normal and diseased states within the CNS. Expert Opinion Gaining insight into the mechanism/s involved in the regulation of nNOS would provide novel strategies for manipulating nNOS directed therapeutic modalities in the future, including catalytically active dimer stabilization and protein-protein interactions with intracellular protein effectors. Ultimately, this is expected to provide tools to improve autonomic dysregulation in various diseases such as heart failure, hypertension, and diabetes. PMID:27885874

Chemical Composition and Oxidation State of Iron-Containing Aerosol Particles Over West Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Fan, S.; Yu, S.; Lai, B.; Gao, Y.

2017-12-01

Iron is a limiting micronutrient element critical for the marine ecosystem. In the extensive high-nutrient low-chlorophyll (HNLC) regions of the Southern Ocean, the activities of phytoplankton are partly controlled by iron (Fe) from different sources, including atmospheric deposition. Among important properties of atmospheric Fe are the elemental composition and Fe oxidation state of Fe-containing aerosol particles, as these properties affect aerosol Fe solubility. To explore these issues, aerosol samples were collected at Palmer Station in West Antarctic Peninsula. Samples were analyzed by submicron synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near edge structure (XANES) spectroscopy for the Fe oxidation state and elemental composition of aerosol particles. The morphological information of aerosol particles was also observed by the high-resolution fluorescence microscopy, revealing possible sources and formation processes of iron-containing particles. More detailed results will be discussed in this presentation.

Voltage-induced Metal-Insulator Transitions in Perovskite Oxide Thin Films Doped with Strongly Correlelated Electrons

NASA Astrophysics Data System (ADS)

Wang, Yudi; Gil Kim, Soo; Chen, I.-Wei

2007-03-01

We have observed a reversible metal-insulator transition in perovskite oxide thin films that can be controlled by charge trapping pumped by a bipolar voltage bias. In the as-fabricated state, the thin film is metallic with a very low resistance comparable to that of the metallic bottom electrode, showing decreasing resistance with decreasing temperature. This metallic state switches to a high-resistance state after applying a voltage bias: such state is non-ohmic showing a negative temperature dependence of resistance. Switching at essentially the same voltage bias was observed down to 2K. The metal-insulator transition is attributed to charge trapping that disorders the energy of correlated electron states in the conduction band. By increasing the amount of charge trapped, which increases the disorder relative to the band width, increasingly more insulating states with a stronger temperature dependence of resistivity are accessed. This metal-insulator transition provides a platform to engineer new nonvolatile memory that does not require heat (as in phase transition) or dielectric breakdown (as in most other oxide resistance devices).

Passivation of oxide traps and interface states in GaAs metal-oxide-semiconductor capacitor by LaTaON passivation layer and fluorine incorporation

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

Liu, L. N.; Choi, H. W.; Lai, P. T., E-mail: laip@eee.hku.hk

2015-11-23

GaAs metal-oxide-semiconductor capacitor with TaYON/LaTaON gate-oxide stack and fluorine-plasma treatment is fabricated and compared with its counterparts without the LaTaON passivation interlayer or the fluorine treatment. Experimental results show that the sample exhibits better characteristics: low interface-state density (8 × 10{sup 11 }cm{sup −2}/eV), small flatband voltage (0.69 V), good capacitance-voltage behavior, small frequency dispersion, and small gate leakage current (6.35 × 10{sup −6} A/cm{sup 2} at V{sub fb} + 1 V). These should be attributed to the suppressed growth of unstable Ga and As oxides on the GaAs surface during gate-oxide annealing by the LaTaON interlayer and fluorine incorporation, and the passivating effects of fluorine atoms on the acceptor-likemore » interface and near-interface traps.« less

How can I know what I'm feeling? Obsessive-compulsive tendencies and induced doubt are related to reduced access to emotional states.

PubMed

Dar, Reuven; Lazarov, Amit; Liberman, Nira

2016-09-01

People's feelings are not always accessible to them, and this might be especially the case for some individuals and in some situations. Based on our model of obsessive-compulsive disorder, we predicted that obsessive-compulsive (OC) tendencies and situationally induced doubt would be associated with decreased access to one's own emotions. In the first two studies we examined the relationships between OC tendencies and performance on the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). In Study 3 we undermined participants' confidence in their ability to accurately assess their own emotions and assessed the effect of this manipulation on MSCEIT performance. As predicted, OC tendencies were associated with lower scores on the Experiential area of the MSCEIT, which relies on access to experienced emotions, but not on the Strategic area, which relies on semantic knowledge about emotions. Similarly, undermining participants' confidence in their own emotions reduced their scores on the Experiential, but not on the Strategic area of the MSCEIT. The findings should be replicated with a clinical OCD population and with other measures of emotional experience. These studies suggest that impaired access to emotional states may be caused by doubting those states, that it characterizes people with high OC tendencies, and that it might be a manifestation of a more general difficulty in accessing internal states. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spin-Orbit Coupling Controlled J = 3 / 2 Electronic Ground State in 5 d 3 Oxides

DOE PAGES

Taylor, A. E.; Calder, S.; Morrow, R.; ...

2017-05-16

Spin-orbit entanglement in 5d-based transition metal oxides (TMOs) has been identified as a route to a host of unconventional physical states including quantum spin liquids, Weyl semimetals, and axion insulators. Yet despite intense interest, no clear rules have emerged for the treatment of spin-orbit coupling (SOC) in 5d TMOs outside of idealised LS or jj coupling paradigms. This is exemplified in 5d 3 oxides in which an orbitally-quenched singlet ground state is anticipated, yet SOC is manifest in the observed magnetic properties. Here we solve this long-outstanding puzzle by revealing that the electronic ground state of Os5+ 5d 3 ionsmore » is an unquenched J = 3/2 state. Resonant inelastic x-ray scattering (RIXS) in Ca3LiOsO6 and Ba 2YOsO 6 exposes a SOC-controlled splitting of the t 2g manifold. The results are successfully described using an intermediate-coupling framework in which oxygen hybridisation promotes the breakdown of the orbital singlet. This framework opens the door to realistic treatment of SOC across a range of 5d TMOs beyond the 5d 3 case.« less

Spin-Orbit Coupling Controlled J = 3 / 2 Electronic Ground State in 5 d 3 Oxides

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

Taylor, A. E.; Calder, S.; Morrow, R.

Spin-orbit entanglement in 5d-based transition metal oxides (TMOs) has been identified as a route to a host of unconventional physical states including quantum spin liquids, Weyl semimetals, and axion insulators. Yet despite intense interest, no clear rules have emerged for the treatment of spin-orbit coupling (SOC) in 5d TMOs outside of idealised LS or jj coupling paradigms. This is exemplified in 5d 3 oxides in which an orbitally-quenched singlet ground state is anticipated, yet SOC is manifest in the observed magnetic properties. Here we solve this long-outstanding puzzle by revealing that the electronic ground state of Os5+ 5d 3 ionsmore » is an unquenched J = 3/2 state. Resonant inelastic x-ray scattering (RIXS) in Ca3LiOsO6 and Ba 2YOsO 6 exposes a SOC-controlled splitting of the t 2g manifold. The results are successfully described using an intermediate-coupling framework in which oxygen hybridisation promotes the breakdown of the orbital singlet. This framework opens the door to realistic treatment of SOC across a range of 5d TMOs beyond the 5d 3 case.« less

Optimization modeling to maximize population access to comprehensive stroke centers

PubMed Central

Branas, Charles C.; Kasner, Scott E.; Wolff, Catherine; Williams, Justin C.; Albright, Karen C.; Carr, Brendan G.

2015-01-01

Objective: The location of comprehensive stroke centers (CSCs) is critical to ensuring rapid access to acute stroke therapies; we conducted a population-level virtual trial simulating change in access to CSCs using optimization modeling to selectively convert primary stroke centers (PSCs) to CSCs. Methods: Up to 20 certified PSCs per state were selected for conversion to maximize the population with 60-minute CSC access by ground and air. Access was compared across states based on region and the presence of state-level emergency medical service policies preferentially routing patients to stroke centers. Results: In 2010, there were 811 Joint Commission PSCs and 0 CSCs in the United States. Of the US population, 65.8% had 60-minute ground access to PSCs. After adding up to 20 optimally located CSCs per state, 63.1% of the US population had 60-minute ground access and 86.0% had 60-minute ground/air access to a CSC. Across states, median CSC access was 55.7% by ground (interquartile range 35.7%–71.5%) and 85.3% by ground/air (interquartile range 59.8%–92.1%). Ground access was lower in Stroke Belt states compared with non–Stroke Belt states (32.0% vs 58.6%, p = 0.02) and lower in states without emergency medical service routing policies (52.7% vs 68.3%, p = 0.04). Conclusion: Optimal system simulation can be used to develop efficient care systems that maximize accessibility. Under optimal conditions, a large proportion of the US population will be unable to access a CSC within 60 minutes. PMID:25740858

Optimization modeling to maximize population access to comprehensive stroke centers.

PubMed

Mullen, Michael T; Branas, Charles C; Kasner, Scott E; Wolff, Catherine; Williams, Justin C; Albright, Karen C; Carr, Brendan G

2015-03-24

The location of comprehensive stroke centers (CSCs) is critical to ensuring rapid access to acute stroke therapies; we conducted a population-level virtual trial simulating change in access to CSCs using optimization modeling to selectively convert primary stroke centers (PSCs) to CSCs. Up to 20 certified PSCs per state were selected for conversion to maximize the population with 60-minute CSC access by ground and air. Access was compared across states based on region and the presence of state-level emergency medical service policies preferentially routing patients to stroke centers. In 2010, there were 811 Joint Commission PSCs and 0 CSCs in the United States. Of the US population, 65.8% had 60-minute ground access to PSCs. After adding up to 20 optimally located CSCs per state, 63.1% of the US population had 60-minute ground access and 86.0% had 60-minute ground/air access to a CSC. Across states, median CSC access was 55.7% by ground (interquartile range 35.7%-71.5%) and 85.3% by ground/air (interquartile range 59.8%-92.1%). Ground access was lower in Stroke Belt states compared with non-Stroke Belt states (32.0% vs 58.6%, p = 0.02) and lower in states without emergency medical service routing policies (52.7% vs 68.3%, p = 0.04). Optimal system simulation can be used to develop efficient care systems that maximize accessibility. Under optimal conditions, a large proportion of the US population will be unable to access a CSC within 60 minutes. © 2015 American Academy of Neurology.

Disparities in access to effective treatment for infertility in the United States: an Ethics Committee opinion.

PubMed

2015-11-01

In the United States, economic, racial, ethnic, geographic, and other disparities exist in access to fertility treatment and in treatment outcomes. This opinion examines the factors that contribute to these disparities and proposes actions to address them. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Effect of mifepristone on abortion access in the United States.

PubMed

Finer, Lawrence B; Wei, Junhow

2009-09-01

To examine the pattern of mifepristone uptake in the United States and whether the introduction of this drug has facilitated access to abortion services. Using data from a national census of abortion providers and from the U.S. distributor of mifepristone, we assessed the number and proportion of abortions performed using mifepristone, the distribution of mifepristone providers by provider type and medical specialty, and the geographic distribution of mifepristone and surgical providers. The number of mifepristone providers increased from 208 in the last 2 months of 2000 to 700 in 2001, the first full year of availability, and to 902 in 2007. Some 158,000 mifepristone abortions were performed in 2007, representing an estimated 14% of all abortions and 21% of eligible early abortions. Physicians represented 51% of mifepristone providers but accounted for just 11% of abortions; most were obstetrician-gynecologists. The proportion of abortions in each state performed using mifepristone ranged from 0% to 80%. Most mifepristone abortions were performed at or near facilities that also provided surgical abortion. Only five mifepristone-only providers of 10 or more abortions were located farther than 50 miles from any surgical provider of 400 or more abortions. Mifepristone has become an integral part of abortion provision in the United States and likely has contributed to a trend toward very early abortions. However, expectations that approval of mifepristone would result in a wider range of providers offering abortion have not yet been met, and mifepristone has not brought a major improvement in the geographic availability of abortion. III.

C—H Oxidation of Ingenanes Enables Potent and Selective Protein Kinase C Isoform Activation

PubMed Central

Jin, Yehua; Yeh, Chien‐Hung; Kuttruff, Christian A.; Jørgensen, Lars; Dünstl, Georg; Felding, Jakob; Natarajan, Swaminathan R.

2015-01-01

Abstract Ingenol derivatives with varying degrees of oxidation were prepared by two‐phase terpene synthesis. This strategy has allowed access to analogues that cannot be prepared by semisynthesis from natural ingenol. Complex ingenanes resulting from divergent C—H oxidation of a common intermediate were found to interact with protein kinase C in a manner that correlates well with the oxidation state of the ingenane core. Even though previous work on ingenanes has suggested a strong correlation between potential to activate PKCδ and induction of neutrophil oxidative burst, the current study shows that the potential to activate PKCβII is of key importance while interaction with PKCδ is dispensable. Thus, key modifications of the ingenane core allowed PKC isoform selectivity wherein PKCδ‐driven activation of keratinocytes is strongly reduced or even absent while PKCβII‐driven activation of neutrophils is retained. PMID:26418078

ENVIRONMENTAL VARIABLES CONTROLLING NITRIC OXIDE EMISSIONS FROM AGRICULTURAL SOILS IN THE SOUTHEAST UNITED STATES

EPA Science Inventory

Fluxes of nitric oxide (NO) were measured during the summer of 1994 (12 July to 11 August) in the Upper Coastal Plain of North Carolina in a continuing effort to characterize NO emissions from intensively managed agricultural soils in the southeastern United States. Previous work...

NEPC Review: "Tackling Gaps in Access to Strong Teachers: What State Leaders Can Do (The Education Trust, October 2017)

ERIC Educational Resources Information Center

Santoro, Doris A.

2017-01-01

The Every Students Succeeds Act (ESSA) directs states and districts to identify equity gaps in students' access to excellent educators and transformative school leaders. States are encouraged to use Title II funds strategically in order to identify and remedy these gaps. A new report from The Education Trust draws on ESSA documents and state…

Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

PubMed

Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

2017-10-04

We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10 -3 S cm -1 ) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g -1 at 0.1 A g -1 ), better rate capability (64% capacity retention until 20 A g -1 ), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg -1 at 1 A g -1 ) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

Benefits of access management.

DOT National Transportation Integrated Search

2003-01-01

This brochure serves as a guide to the major benefits of several : access management techniques in use across the United States. The : purpose of this brochure is to provide a comprehensive and succinct : examination of the benefits of access managem...

Molecular water oxidation mechanisms followed by transition metals: state of the art.

PubMed

Sala, Xavier; Maji, Somnath; Bofill, Roger; García-Antón, Jordi; Escriche, Lluís; Llobet, Antoni

2014-02-18

One clean alternative to fossil fuels would be to split water using sunlight. However, to achieve this goal, researchers still need to fully understand and control several key chemical reactions. One of them is the catalytic oxidation of water to molecular oxygen, which also occurs at the oxygen evolving center of photosystem II in green plants and algae. Despite its importance for biology and renewable energy, the mechanism of this reaction is not fully understood. Transition metal water oxidation catalysts in homogeneous media offer a superb platform for researchers to investigate and extract the crucial information to describe the different steps involved in this complex reaction accurately. The mechanistic information extracted at a molecular level allows researchers to understand both the factors that govern this reaction and the ones that derail the system to cause decomposition. As a result, rugged and efficient water oxidation catalysts with potential technological applications can be developed. In this Account, we discuss the current mechanistic understanding of the water oxidation reaction catalyzed by transition metals in the homogeneous phase, based on work developed in our laboratories and complemented by research from other groups. Rather than reviewing all of the catalysts described to date, we focus systematically on the several key elements and their rationale from molecules studied in homogeneous media. We organize these catalysts based on how the crucial oxygen-oxygen bond step takes place, whether via a water nucleophilic attack or via the interaction of two M-O units, rather than based on the nuclearity of the water oxidation catalysts. Furthermore we have used DFT methodology to characterize key intermediates and transition states. The combination of both theory and experiments has allowed us to get a complete view of the water oxidation cycle for the different catalysts studied. Finally, we also describe the various deactivation pathways for

Does a higher metal oxidation state necessarily imply higher reactivity toward H-atom transfer? A computational study of C-H bond oxidation by high-valent iron-oxo and -nitrido complexes.

PubMed

Geng, Caiyun; Ye, Shengfa; Neese, Frank

2014-04-28

In this work, the reactions of C-H bond activation by two series of iron-oxo ( (Fe(IV)), (Fe(V)), (Fe(VI))) and -nitrido model complexes ( (Fe(IV)), (Fe(V)), (Fe(VI))) with a nearly identical coordination geometry but varying iron oxidation states ranging from iv to vi were comprehensively investigated using density functional theory. We found that in a distorted octahedral coordination environment, the iron-oxo species and their isoelectronic nitrido analogues feature totally different intrinsic reactivities toward C-H bond cleavage. In the case of the iron-oxo complexes, the reaction barrier monotonically decreases as the iron oxidation state increases, consistent with the gradually enhanced electrophilicity across the series. The iron-nitrido complex is less reactive than its isoelectronic iron-oxo species, and more interestingly, a counterintuitive reactivity pattern was observed, i.e. the activation barriers essentially remain constant independent of the iron oxidation states. The detailed analysis using the Polanyi principle demonstrates that the different reactivities between these two series originate from the distinct thermodynamic driving forces, more specifically, the bond dissociation energies (BDEE-Hs, E = O, N) of the nascent E-H bonds in the FeE-H products. Further decomposition of the BDEE-Hs into the electron and proton affinity components shed light on how the oxidation states modulate the BDEE-Hs of the two series.

Access to Attainment: An Access Agenda for 21st Century College Students

ERIC Educational Resources Information Center

Miller, Abby; Valle, Katherine; Engle, Jennifer; Cooper, Michelle

2014-01-01

This report, "Access to Attainment: An Access Agenda for 21st Century College Students," examines the challenges facing 21st century students and presents strategies for addressing these challenges through policy-and practice-based solutions at the institutional, state and national levels. Recommendations include implementing a…

Positron states and annihilation characteristics of surface-trapped positrons at the oxidized Cu(110) surface

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Olenga, Antoine; Weiss, A. H.

2013-03-01

The process by which oxide layers are formed on metal surfaces is still not well understood. In this work we present the results of theoretical studies of positron states and annihilation characteristics of surface-trapped positrons at the oxidized Cu(110) surface. An ab-initio investigation of stability and associated electronic properties of different adsorption phases of oxygen on Cu(110) has been performed on the basis of density functional theory and using DMOl3 code. The changes in the positron work function and the surface dipole moment when oxygen atoms occupy on-surface and sub-surface sites have been attributed to charge redistribution within the first two layers, buckling effects within each layer and interlayer expansion. The computed positron binding energy, positron surface state wave function, and annihilation probabilities of surface trapped positrons with relevant core electrons demonstrate their sensitivity to oxygen coverage, elemental content, atomic structure of the topmost layers of surfaces, and charge transfer effects. Theoretical results are compared with experimental data obtained from studies of oxidized transition metal surfaces using positron annihilation induced Auger electron spectroscopy. This work was supported in part by the National Science Foundation Grant DMR-0907679.

Diversity of Chemical Bonding and Oxidation States in MS4 Molecules of Group 8 Elements.

PubMed

Huang, Wei; Jiang, Ning; Schwarz, W H Eugen; Yang, Ping; Li, Jun

2017-08-04

The geometric and electronic ground-state structures of 30 isomers of six MS 4 molecules (M=Group 8 metals Fe, Ru, Os, Hs, Sm, and Pu) have been studied by using quantum-chemical density functional theory and correlated wavefunction approaches. The MS 4 species were compared to analogous MO 4 species recently investigated (W. Huang, W.-H. Xu, W. H. E. Schwarz, J. Li, Inorg. Chem. 2016, 55, 4616). A metal oxidation state (MOS) with a high value of eight appeared in the low-spin singlet T d geometric species (Os,Hs)S 4 and (Ru,Os,Hs)O 4 , whereas a low MOS of two appeared in the high-spin septet D 2d species Fe(S 2 ) 2 and (slightly excited) metastable Fe(O 2 ) 2 . The ground states of all other molecules had intermediate MOS values, with S 2- , S 2 2- , S 2 1- (and O 2- , O 1- , O 2 2- , O 2 1- ) ligands bonded by ionic, covalent, and correlative contributions. The known tendencies toward lower MOS on going from oxides to sulfides, from Hs to Os to Ru, and from Pu to Sm, and the specific behavior of Fe, were found to arise from the different atomic orbital energies and radii of the (n-1)p core and (n-1)d and (n-2)f valence shells of the metal atoms in row n of the periodic table. The comparative results of the electronic and geometric structures of the MO 4 and MS 4 species provides insight into the periodicity of oxidation states and bonding. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pharmaceutical Market Access: current state of affairs and key challenges - results of the Market Access Launch Excellence Inventory (MALEI).

PubMed

Koch, Marcus A

2015-01-01

To take inventory of the current state of affairs of Market Access Launch Excellence in the life sciences industry. To identify key gaps and challenges for Market Access (MA) and discuss how they can be addressed. To generate a baseline for benchmarking MA launch excellence. An online survey was conducted with pharmaceutical executives primarily working in MA, marketing, or general management. The survey aimed to evaluate MA excellence prerequisites across the product life cycle (rated by importance and level of implementation) and to describe MA activity models in the respective companies. Composite scores were calculated from respondents' ratings and answers. Implementation levels of MA excellence prerequisites generally lagged behind their perceived importance. Item importance and the respective level of implementation correlated well, which can be interpreted as proof of the validity of the questionnaire. The following areas were shown to be particularly underimplemented: 1) early integration of MA and health economic considerations in research and development decision making, 2) developing true partnerships with payers, including the development of services 'beyond the pill', and 3) consideration of human resource and talent management. The concept of importance-adjusted implementation levels as a hybrid parameter was introduced and shown to be a viable tool for benchmarking purposes. More than 70% of respondents indicated that their companies will invest broadly in MA in terms of capital and headcount within the next 3 years. MA (launch) excellence needs to be further developed in order to close implementation gaps across the entire product life cycle. As MA is a comparatively young pharmaceutical discipline in a complex and dynamic environment, this effort will require strategic focus and dedication. The Market Access Launch Excellence Inventory benchmarking tool may help guide decision makers to prioritize their endeavors.

23 CFR 658.19 - Reasonable access.

Code of Federal Regulations, 2010 CFR

2010-04-01

... National Network. (c) Nothing in this section shall be construed as preventing any State or local...-mile from the National Network using the most reasonable and practicable route available except for... requests for access from the National Network. (2) State access review processes shall provide for: (i) One...

49 CFR 1546.213 - Access to cargo: Security threat assessments for cargo personnel in the United States.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Access to cargo: Security threat assessments for...: Security threat assessments for cargo personnel in the United States. This section applies in the United...— (1) Each individual must successfully complete a security threat assessment or comparable security...

Health care access and utilization among children of single working and nonworking mothers in the United States.

PubMed

Clarke, Tainya C; Arheart, Kristopher L; Muennig, Peter; Fleming, Lora E; Caban-Martinez, Alberto J; Dietz, Noella; Lee, David J

2011-01-01

To examine indicators of health care access and utilization among children of working and nonworking single mothers in the United States, the authors used data on unmarried women participating in the 1997-2008 National Health Interview Survey who financially supported children under 18 years of age (n = 21,842). Stratified by maternal employment, the analyses assessed health care access and utilization for all children. Outcome variables included delayed care, unmet care, lack of prescription medication, no usual place of care, no well-child visit, and no doctor's visit. The analyses reveal that maternal employment status was not associated with health care access and utilization. The strongest predictors of low access/utilization included no health insurance and intermittent health insurance in the previous 12 months, relative to those with continuous private health insurance coverage (odds ratio ranges 3.2-13.5 and 1.3-10.3, respectively). Children with continuous public health insurance compared favorably with those having continuous private health insurance on three of six access/utilization indicators (odds ratio range 0.63-0.85). As these results show, health care access and utilization for the children of single mothers are not optimal. Passage of the U.S. Healthcare Reform Bill (HR 3590) will probably increase the number of children with health insurance and improve these indicators.

Minimum Ages of Legal Access for Tobacco in the United States From 1863 to 2015

PubMed Central

Glantz, Stanton A.

2016-01-01

In the United States, state laws establish a minimum age of legal access (MLA) for most tobacco products at 18 years. We reviewed the history of these laws with internal tobacco industry documents and newspaper archives from 1860 to 2014. The laws appeared in the 1880s; by 1920, half of states had set MLAs of at least 21 years. After 1920, tobacco industry lobbying eroded them to between 16 and 18 years. By the 1980s, the tobacco industry viewed restoration of higher MLAs as a critical business threat. The industry’s political advocacy reflects its assessment that recruiting youth smokers is critical to its survival. The increasing evidence on tobacco addiction suggests that restoring MLAs to 21 years would reduce smoking initiation and prevalence, particularly among those younger than 18 years. PMID:27196658

Electronic states in oxidized NaxCoO2 as revealed by X-ray absorption spectroscopy coupled with ab initio calculation

NASA Astrophysics Data System (ADS)

Niwa, Hideharu; Higashiyama, Kazuyuki; Amaha, Kaoru; Kobayashi, Wataru; Moritomo, Yutaka

2018-04-01

Layered cobalt oxides are promising cathode materials for sodium ion secondary batteries (SIBs). By combined study of the X-ray absorption spectroscopy (XAS) around the O K-edge and ab initio calculation, we investigated the electronic state of the NaxCoO2 with different oxidization state, i.e, in O3-Na0.91CoO2 (CoO2-0.91) and P2-Na0.66CoO2 (CoO2-0.66). The O K-edge spectra in the pre-edge (529-536 eV) region shows significant change with oxidization of NaxCoO2. In O3-Na0.91CoO2, the spectra shows an intense band (B band) at 531 eV. In P2-Na0.66CoO2, the spectral weight of the B band increases and a new band (A band) appears at 530 eV. These spectral changes are qualitatively reproduced by the calculated partial density of states (pDOSs) of O3-NaCoO2 and P2-Na1/2CoO2. These results indicate that the electrons are partially removed from the O 2p state with oxidization of NaxCoO2.

Tuning resistance states by thickness control in an electroforming-free nanometallic complementary resistance random access memory

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

Yang, Xiang; Lu, Yang; Lee, Jongho

2016-01-04

Tuning low resistance state is crucial for resistance random access memory (RRAM) that aims to achieve optimal read margin and design flexibility. By back-to-back stacking two nanometallic bipolar RRAMs with different thickness into a complementary structure, we have found that its low resistance can be reliably tuned over several orders of magnitude. Such high tunability originates from the exponential thickness dependence of the high resistance state of nanometallic RRAM, in which electron wave localization in a random network gives rise to the unique scaling behavior. The complementary nanometallic RRAM provides electroforming-free, multi-resistance-state, sub-100 ns switching capability with advantageous characteristics formore » memory arrays.« less

Availability and Accessibility in an Open Access Institutional Repository: A Case Study

ERIC Educational Resources Information Center

Lee, Jongwook; Burnett, Gary; Vandegrift, Micah; Baeg, Jung Hoon; Morris, Richard

2015-01-01

Introduction: This study explores the extent to which an institutional repository makes papers available and accessible on the open Web by using 170 journal articles housed in DigiNole Commons, the institutional repository at Florida State University. Method: To analyse the repository's impact on availability and accessibility, we conducted…

Limited School Drinking Water Access for Youth.

PubMed

Kenney, Erica L; Gortmaker, Steven L; Cohen, Juliana F W; Rimm, Eric B; Cradock, Angie L

2016-07-01

Providing children and youth with safe, adequate drinking water access during school is essential for health. This study used objectively measured data to investigate the extent to which schools provide drinking water access that meets state and federal policies. We visited 59 middle and high schools in Massachusetts during spring 2012. Trained research assistants documented the type, location, and working condition of all water access points throughout each school building using a standard protocol. School food service directors (FSDs) completed surveys reporting water access in cafeterias. We evaluated school compliance with state plumbing codes and federal regulations and compared FSD self-reports of water access with direct observation; data were analyzed in 2014. On average, each school had 1.5 (standard deviation: .6) water sources per 75 students; 82% (standard deviation: 20) were functioning and fewer (70%) were both clean and functioning. Less than half of the schools met the federal Healthy Hunger-Free Kids Act requirement for free water access during lunch; 18 schools (31%) provided bottled water for purchase but no free water. Slightly over half (59%) met the Massachusetts state plumbing code. FSDs overestimated free drinking water access compared to direct observation (96% FSD reported vs. 48% observed, kappa = .07, p = .17). School drinking water access may be limited. In this study, many schools did not meet state or federal policies for minimum student drinking water access. School administrative staff may not accurately report water access. Public health action is needed to increase school drinking water access. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Introducing a Simple Equation to Express Oxidation States as an Alternative to Using Rules Associated with Words Alone

ERIC Educational Resources Information Center

Minkiewicz, Piotr; Darewicz, Malgorzata; Iwaniak, Anna

2018-01-01

A simple equation to calculate the oxidation states (oxidation numbers) of individual atoms in molecules and ions may be introduced instead of rules associated with words alone. The equation includes two of three categories of bonds, classified as proposed by Goodstein: number of bonds with more electronegative atoms and number of bonds with less…

Program Retrieval/Dissemination: A Solid State Random Access System.

ERIC Educational Resources Information Center

Weeks, Walter O., Jr.

The trend toward greater flexibility in educational methods has led to a need for better and more rapid access to a variety of aural and audiovisual resource materials. This in turn has demanded the development of a flexible, reliable system of hardware designed to aid existing distribution methods in providing such access. The system must be…

Trends in the Prevalence of Severe Obesity and Bariatric Surgery Access: A State-Level Analysis from 2011 to 2014.

PubMed

Henkel, Dana S; Mora-Pinzon, Maria; Remington, Patrick L; Jolles, Sally A; Voils, Corrine I; Gould, Jon C; Kothari, Shanu N; Funk, Luke M

2017-07-01

Understanding what proportion of the eligible population is undergoing bariatric surgery at the state level provides critical insight into characterizing bariatric surgery access. We sought to describe statewide trends in severe obesity demographics and report bariatric surgery volume in Wisconsin from 2011 to 2014. Self-reported data from the Behavioral Risk Factor Surveillance System (BRFSS) were used to calculate prevalence rates of severe obesity (class II and III) in Wisconsin. Bariatric surgery volume data were analyzed from the Wisconsin Hospital Association. A survey was sent to all American Society for Metabolic and Bariatric Surgery member bariatric surgeons in Wisconsin to assess perspectives on bariatric surgery access, insurance coverage, and referral processes. The prevalence of severe obesity in Wisconsin increased by 30% from 2011 to 2014 (10.4%-13.2%; P = .035); the odds of severe obesity nearly doubled for adults age 20-39 (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.3-3.0). During this time, the volume of bariatric surgery declined by 4.2%; (1432 to 1372; P < .001), whereas the rates of bariatric surgery per 1000 persons with severe obesity declined by 25.7% (3.5 to 2.6/1000). A majority (72%) of bariatric surgeon respondents felt bariatric surgery access either worsened or remained the same over the last 4 years. Severe obesity increased significantly in Wisconsin over a 4-year period, whereas bariatric surgery rates among severely obese persons have remained largely unchanged and are substantially below the national average. Combining the state-level obesity survey data and bariatric surgery administrative data may be a useful approach for tracking bariatric surgery access throughout the United States.

20 CFR 652.207 - How does a State meet the requirement for universal access to services provided under the Act?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false How does a State meet the requirement for universal access to services provided under the Act? 652.207 Section 652.207 Employees' Benefits EMPLOYMENT... exercising this discretion, a State must meet the Act's requirements. (b) These requirements are: (1) Labor...

Metal Oxide Nanoparticles: The Importance of Size, Shape, Chemical Composition, and Valence State in Determining Toxicity

NASA Astrophysics Data System (ADS)

Dunnick, Katherine

Nanoparticles, which are defined as a structure with at least one dimension between 1 and 100 nm, have the potential to be used in a variety of consumer products due to their improved functionality compared to similar particles of larger size. Their small size is associated with increased strength, improved catalytic properties, and increased reactivity; however, their size is also associated with increased toxicity in vitro and in vivo. Numerous toxicological studies have been conducted to determine the properties of nanomaterials that increase their toxicity in order to manufacture new nanomaterials with decreased toxicity. Data indicates that size, shape, chemical composition, and valence state of nanomaterials can dramatically alter their toxicity profile. Therefore, the purpose of this dissertation was to determine how altering the shape, size, and chemical composition of various metal oxide nanoparticles would affect their toxicity. Metal oxides are used in variety of consumer products, from spray-sun screens, to food coloring agents; thus, understanding the toxicity of metal oxides and determining which aspects affect their toxicity may provide safe alternatives nanomaterials for continued use in manufacturing. Tungstate nanoparticles toxicity was assessed in an in vitro model using RAW 264.7 cells. The size, shape, and chemical composition of these nanomaterials were altered and the effect on reactive oxygen species and general cytotoxicity was determined using a variety of techniques. Results demonstrate that shape was important in reactive oxygen species production as wires were able to induce significant reactive oxygen species compared to spheres. Shape, size, and chemical composition did not have much effect on the overall toxicity of these nanoparticles in RAW 264.7 cells over a 72 hour time course, implicating that the base material of the nanoparticles was not toxic in these cells. To further assess how chemical composition can affect toxicity

[Accessibility of health services for users].

PubMed

Sousa-Fragoso, M A; Villarreal-Ríos, E

2000-01-01

To measure the accessibility to health services and determine a model to explain this accessibility. All states of the Mexican Republic were included. The measurement of accessibility considers the availability of resources and the perception of barriers. Place of residence, education, participation in the work forces and household conditions were included in the model. The average of availability resources was 64.59% sd 15.68 (range 42 to 100) and the average corresponding to perception of barriers, 87.61% SD 4.04 (range 79.23 to 95.65). Accessibility was 71.50% SD 10.74 (range 56 to 96). The states with highest accessibility were the Federal District and Baja California Sur and the lowest, Chiapas and Oaxaca. The model included education and labor participation (R2 = 0.67, p < 0.05). Accessibility was determined by socioeconomic factors.

Water oxidation by Ruthenium complexes incorporating multifunctional biipyridyl diphosphonate ligands

DOE PAGES

Xie, Yan; Shaffer, David W.; Lewandowska-Andralojc, Anna; ...

2016-05-11

Here, we describe herein the synthesis and characterization of ruthenium complexes with multifunctional bipyridyl diphosphonate ligands as well as initial water oxidation studies. In these complexes, the phosphonate groups provide redox-potential leveling through charge compensation and σ donation to allow facile access to high oxidation states. These complexes display unique pH-dependent electrochemistry associated with deprotonation of the phosphonic acid groups. The position of these groups allows them to shuttle protons in and out of the catalytic site and reduce activation barriers. A mechanism for water oxidation by these catalysts is proposed on the basis of experimental results and DFT calculations.more » The unprecedented attack of water at a neutral six-coordinate [Ru IV] center to yield an anionic seven-coordinate [Ru IV–OH] – intermediate is one of the key steps of a single-site mechanism in which all species are anionic or neutral. These complexes are among the fastest single-site catalysts reported to date.« less

No effect of H2O degassing on the oxidation state of magmatic liquids

NASA Astrophysics Data System (ADS)

Waters, Laura E.; Lange, Rebecca A.

2016-08-01

The underlying cause for why subduction-zone magmas are systematically more oxidized than those formed at mid-ocean spreading ridges is a topic of vigorous debate. It is either a primary feature inherited from the subduction of oxidized oceanic crust into the mantle or a secondary feature that develops because of H2O degassing and/or magma differentiation. Low total iron contents and high melt H2O contents render rhyolites sensitive to any effect of H2O degassing on ferric-ferrous ratios. Here, pre-eruptive magmatic Fe2+ concentrations, measured using Fe-Ti oxides that co-crystallized with silicate phenocrysts under hydrous conditions, are compared with Fe2+ post-eruptive concentrations in ten crystal-poor, fully-degassed obsidian samples; five are microlite free. No effect of H2O degassing on the ferric-ferrous ratio is found. In addition, Fe-Ti oxide data from this study and the literature show that arc magmas are systematically more oxidized than both basalts and hydrous silicic melts from Iceland and Yellowstone prior to extensive degassing. Nor is there any evidence that differentiation (i.e., crystal fractionation, crustal assimilation) is the cause of the higher redox state of arc magmas relative to those of Iceland/Yellowstone rhyolites. Instead, the evidence points to subduction of oxidized crust and the release of an H2O-rich fluid and/or melt with a high oxygen fugacity (fO2), which plays a role during H2O-flux melting of the mantle in creating basalts that are relatively oxidized.

A Semi-Analytical Extraction Method for Interface and Bulk Density of States in Metal Oxide Thin-Film Transistors

PubMed Central

Chen, Weifeng; Wu, Weijing; Zhou, Lei; Xu, Miao; Wang, Lei; Peng, Junbiao

2018-01-01

A semi-analytical extraction method of interface and bulk density of states (DOS) is proposed by using the low-frequency capacitance–voltage characteristics and current–voltage characteristics of indium zinc oxide thin-film transistors (IZO TFTs). In this work, an exponential potential distribution along the depth direction of the active layer is assumed and confirmed by numerical solution of Poisson’s equation followed by device simulation. The interface DOS is obtained as a superposition of constant deep states and exponential tail states. Moreover, it is shown that the bulk DOS may be represented by the superposition of exponential deep states and exponential tail states. The extracted values of bulk DOS and interface DOS are further verified by comparing the measured transfer and output characteristics of IZO TFTs with the simulation results by a 2D device simulator ATLAS (Silvaco). As a result, the proposed extraction method may be useful for diagnosing and characterising metal oxide TFTs since it is fast to extract interface and bulk density of states (DOS) simultaneously. PMID:29534492

Calculated momentum dependence of Zhang-Rice states in transition metal oxides.

PubMed

Yin, Quan; Gordienko, Alexey; Wan, Xiangang; Savrasov, Sergey Y

2008-02-15

Using a combination of local density functional theory and cluster exact diagonalization based dynamical mean field theory, we calculate many-body electronic structures of several Mott insulating oxides including undoped high T(c) materials. The dispersions of the lowest occupied electronic states are associated with the Zhang-Rice singlets in cuprates and with doublets, triplets, quadruplets, and quintets in more general cases. Our results agree with angle resolved photoemission experiments including the decrease of the spectral weight of the Zhang-Rice band as it approaches k=0.

Cellulose nanofibril/reduced graphene oxide/carbon nanotube hybrid aerogels for highly flexible and all-solid-state supercapacitors

Treesearch

Qifeng Zheng; Zhiyong Cai; Zhenqiang Ma; Shaoqin Gong

2015-01-01

A novel type of highly flexible and all-solid-state supercapacitor that uses cellulose nanofibril (CNF)/reduced graphene oxide (RGO)/carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4 poly (vinyl alcohol) PVA gel as the electrolyte was developed and is reported here. These flexible solid-state supercapacitors...

Ga-doped indium oxide nanowire phase change random access memory cells

NASA Astrophysics Data System (ADS)

Jin, Bo; Lim, Taekyung; Ju, Sanghyun; Latypov, Marat I.; Kim, Hyoung Seop; Meyyappan, M.; Lee, Jeong-Soo

2014-02-01

Phase change random access memory (PCRAM) devices are usually constructed using tellurium based compounds, but efforts to seek other materials providing desirable memory characteristics have continued. We have fabricated PCRAM devices using Ga-doped In2O3 nanowires with three different Ga compositions (Ga/(In+Ga) atomic ratio: 2.1%, 11.5% and 13.0%), and investigated their phase switching properties. The nanowires (˜40 nm in diameter) can be repeatedly switched between crystalline and amorphous phases, and Ga concentration-dependent memory switching behavior in the nanowires was observed with ultra-fast set/reset rates of 80 ns/20 ns, which are faster than for other competitive phase change materials. The observations of fast set/reset rates and two distinct states with a difference in resistance of two to three orders of magnitude appear promising for nonvolatile information storage. Moreover, we found that increasing the Ga concentration can reduce the power consumption and resistance drift; however, too high a level of Ga doping may cause difficulty in achieving the phase transition.

Genomics and Public Health Research: Can the State Allow Access to Genomic Databases?

PubMed Central

Cousineau, J; Girard, N; Monardes, C; Leroux, T; Jean, M Stanton

2012-01-01

Because many diseases are multifactorial disorders, the scientific progress in genomics and genetics should be taken into consideration in public health research. In this context, genomic databases will constitute an important source of information. Consequently, it is important to identify and characterize the State’s role and authority on matters related to public health, in order to verify whether it has access to such databases while engaging in public health genomic research. We first consider the evolution of the concept of public health, as well as its core functions, using a comparative approach (e.g. WHO, PAHO, CDC and the Canadian province of Quebec). Following an analysis of relevant Quebec legislation, the precautionary principle is examined as a possible avenue to justify State access to and use of genomic databases for research purposes. Finally, we consider the Influenza pandemic plans developed by WHO, Canada, and Quebec, as examples of key tools framing public health decision-making process. We observed that State powers in public health, are not, in Quebec, well adapted to the expansion of genomics research. We propose that the scope of the concept of research in public health should be clear and include the following characteristics: a commitment to the health and well-being of the population and to their determinants; the inclusion of both applied research and basic research; and, an appropriate model of governance (authorization, follow-up, consent, etc.). We also suggest that the strategic approach version of the precautionary principle could guide collective choices in these matters. PMID:23113174

PROCESS OF SECURING PLUTONIUM IN NITRIC ACID SOLUTIONS IN ITS TRIVALENT OXIDATION STATE

DOEpatents

Thomas, J.R.

1958-08-26

>Various processes for the recovery of plutonium require that the plutonium be obtalned and maintained in the reduced or trivalent state in solution. Ferrous ions are commonly used as the reducing agent for this purpose, but it is difficult to maintain the plutonium in a reduced state in nitric acid solutions due to the oxidizing effects of the acid. It has been found that the addition of a stabilizing or holding reductant to such solution prevents reoxidation of the plutonium. Sulfamate ions have been found to be ideally suitable as such a stabilizer even in the presence of nitric acid.

Synchrotron Micro-XANES Measurements of Vanadium Oxidation State in Glasses as a Function of Oxygen Fugacity: Experimental Calibration of Data Relevant to Partition Coefficient Determination

NASA Technical Reports Server (NTRS)

Delaney, J. S.; Sutton, S. R.; Newville, M.; Jones, J. H.; Hanson, B.; Dyar, M. D.; Schreiber, H.

2000-01-01

Oxidation state microanalyses for V in glass have been made by calibrating XANES spectral features with optical spectroscopic measurements. The oxidation state change with fugacity of O2 will strongly influence partitioning results.

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

PubMed

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

2014-08-01

We present a facile synthesis of bioinspired manganese oxides for chemical and photocatalytic water oxidation, starting from a reliable and versatile manganese(II) oxalate single-source precursor (SSP) accessible through an inverse micellar molecular approach. Strikingly, thermal decomposition of the latter precursor in various environments (air, nitrogen, and vacuum) led to the three different mineral phases of bixbyite (Mn2 O3 ), hausmannite (Mn3 O4 ), and manganosite (MnO). Initial chemical water oxidation experiments using ceric ammonium nitrate (CAN) gave the maximum catalytic activity for Mn2 O3 and MnO whereas Mn3 O4 had a limited activity. The substantial increase in the catalytic activity of MnO in chemical water oxidation was demonstrated by the fact that a phase transformation occurs at the surface from nanocrystalline MnO into an amorphous MnOx (1oxidizing agent. Photocatalytic water oxidation in the presence of [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine) as a sensitizer and peroxodisulfate as an electron acceptor was carried out for all three manganese oxides including the newly formed amorphous MnOx . Both Mn2 O3 and the amorphous MnOx exhibit tremendous enhancement in oxygen evolution during photocatalysis and are much higher in comparison to so far known bioinspired manganese oxides and calcium-manganese oxides. Also, for the first time, a new approach for the representation of activities of water oxidation catalysts has been proposed by determining the amount of accessible manganese centers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Size scales over which ordinary chondrites and their parent asteroids are homogeneous in oxidation state and oxygen-isotopic composition

NASA Astrophysics Data System (ADS)

Rubin, Alan E.; Ziegler, Karen; Young, Edward D.

2008-02-01

Literature data demonstrate that on a global, asteroid-wide scale (plausibly on the order of 100 km), ordinary chondrites (OC) have heterogeneous oxidation states and O-isotopic compositions (represented, respectively, by the mean olivine Fa and bulk Δ 17O compositions of equilibrated samples). Samples analyzed here include: (a) two H5 chondrite Antarctic finds (ALHA79046 and TIL 82415) that have the same cosmic-ray exposure age (7.6 Ma) and were probably within ˜1 km of each other when they were excavated from the H-chondrite parent body, (b) different individual stones from the Holbrook L/LL6 fall that were probably within ˜1 m of each other when their parent meteoroid penetrated the Earth's atmosphere, and (c) drill cores from a large slab of the Estacado H6 find located within a few tens of centimeters of each other. Our results indicate that OC are heterogeneous in their bulk oxidation state and O-isotopic composition on 100-km-size scales, but homogeneous on meter-, decimeter- and centimeter-size scales. (On kilometer size scales, oxidation state is heterogeneous, but O isotopes appear to be homogeneous.) The asteroid-wide heterogeneity in oxidation state and O-isotopic composition was inherited from the solar nebula. The homogeneity on small size scales was probably caused in part by fluid-assisted metamorphism and mainly by impact-gardening processes (which are most effective at mixing target materials on scales of ⩽1 m).

Scanning transmission X-ray microscopy probe for in situ mechanism study of graphene-oxide-based resistive random access memory.

PubMed

Nho, Hyun Woo; Kim, Jong Yun; Wang, Jian; Shin, Hyun-Joon; Choi, Sung-Yool; Yoon, Tae Hyun

2014-01-01

Here, an in situ probe for scanning transmission X-ray microscopy (STXM) has been developed and applied to the study of the bipolar resistive switching (BRS) mechanism in an Al/graphene oxide (GO)/Al resistive random access memory (RRAM) device. To perform in situ STXM studies at the C K- and O K-edges, both the RRAM junctions and the I0 junction were fabricated on a single Si3N4 membrane to obtain local XANES spectra at these absorption edges with more delicate I0 normalization. Using this probe combined with the synchrotron-based STXM technique, it was possible to observe unique chemical changes involved in the BRS process of the Al/GO/Al RRAM device. Reversible oxidation and reduction of GO induced by the externally applied bias voltages were observed at the O K-edge XANES feature located at 538.2 eV, which strongly supported the oxygen ion drift model that was recently proposed from ex situ transmission electron microscope studies.

Characterization of the Oxidation State of 229 Th Recoils Implanted in MgF2 for the Search of the Low-lying 229 Th Isomeric State

NASA Astrophysics Data System (ADS)

Barker, Beau; Meyer, Edmund; Schacht, Mike; Collins, Lee; Wilkerson, Marianne; Zhao, Xinxin

2016-05-01

The low-lying (7.8 eV) isomeric state in 229 Th has the potential to become a nuclear frequency standard. 229 Th recoils from 233 U decays have been collected in MgF2 for use in the direct search of the transition. Of interest is the oxidation state of the implanted 229 Th atoms as this can have an influence on the decay mechanisms and photon emission rate. Too determine the oxidation state of the implanted 229 Th recoils we have employed laser induced florescence (LIF), and plan-wave pseudopotential DFT calculations to search for emission from thorium ions in oxidation states less than + 4. Our search focused on detecting emission from Th3+ ions. The DFT calculations predicted the Th3+ state to be the most likely to be present in the crystal after Th4+. We also calculated the band structure for the Th3+ doped MgF2 crystal. For LIF spectra a number of excitation wavelengths were employed, emission spectra in the visible to near-IR were recorded along with time-resolved emission spectra. We have found no evidence for Th3+ in the MgF2 plates. We also analyzed the detection limit of our apprentice and found that the minimum number of Th3+ atoms that we could detect is quite small compared to the number of implanted 229 Th recoils. The number of implanted 229 Th recoils was derived from a γ-ray spectrum by monitoring emission from the daughters of 228 Th. These were present in the MgF2 plates due to a 232 U impurity, which decays to 228 Th, in the source. LA-UR-16-20442.

Co-variability of S 6+ , S 4+ , and S 2- in apatite as a function of oxidation state: Implications for a new oxybarometer

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

Konecke, Brian A.; Fiege, Adrian; Simon, Adam C.

In this study, we use micro-X-ray absorption near-edge structures (μ-XANES) spectroscopy at the S K-edge to investigate the oxidation state of S in natural magmatic-hydrothermal apatite (Durango, Mexico, and Mina Carmen, Chile) and experimental apatites crystallized from volatile-saturated lamproitic melts at 1000 °C and 300 MPa over a broad range of oxygen fugacities [( Embedded Image , FMQ+1.2, FMQ+3; FMQ = fayalite-magnetite-quartz solid buffer]. The data are used to test the hypothesis that S oxidation states other than S6+ may substitute into the apatite structure. Peak energies corresponding to sulfate S6+ (~2482 eV), sulfite S4+ (~2478 eV), and sulfide S2-more » (~2470 eV) were observed in apatite, and the integrated areas of the different sulfur peaks correspond to changes in Embedded Image and bulk S content. Here, multiple tests confirmed that the S oxidation state in apatite remains constant when exposed to the synchrotron beam, at least for up to 1 h exposure (i.e., no irradiation damages). To our knowledge, this observation makes apatite the first mineral to incorporate reduced (S2-), intermediate (S4+), and oxidized (S6+) S in variable proportions as a function of the prevailing Embedded Image of the system. Apatites crystallized under oxidizing conditions (FMQ+1.2 and FMQ+3), where the S6+/STotal peak area ratio in the coexisting glass (i.e., quenched melt) is ~1, are dominated by S6+ with a small contribution of S4+, whereas apatites crystallizing at reduced conditions (FMQ) contain predominantly S2-, lesser amounts of S6+, and possibly traces of S4+. A sulfur oxidation state vs. S concentration analytical line transect across hydrothermally altered apatite from the Mina Carmen iron oxide-apatite (IOA) deposit (Chile) demonstrates that apatite can become enriched in S4+ relative to S6+, indicating metasomatic overprinting via a SO2-bearing fluid or vapor phase. This XANES study demonstrates that as the Embedded Image increases from FQM to FMQ+1

Valence-state reflectometry of complex oxide heterointerfaces

DOE PAGES

Hamann-Borrero, Jorge E.; Macke, Sebastian; Choi, Woo Seok; ...

2016-09-16

Emergent phenomena in transition-metal-oxide heterostructures such as interface superconductivity and magnetism have been attributed to electronic reconstruction, which, however, is difficult to detect and characterise. Here we overcome the associated difficulties to simultaneously address the electronic degrees of freedom and distinguish interface from bulk effects by implementing a novel approach to resonant X-ray reflectivity (RXR). Our RXR study of the chemical and valance profiles along the polar (001) direction of a LaCoO 3 film on NdGaO 3 reveals a pronounced valence-state reconstruction from Co 3+ in the bulk to Co 2+ at the surface, with an areal density close tomore » 0.5 Co 2+ ions per unit cell. An identical film capped with polar (001) LaAlO 3 maintains the Co 3+ valence over its entire thickness. As a result, we interpret this as evidence for electronic reconstruction in the uncapped film, involving the transfer of 0.5e – per unit cell to the subsurface CoO 2 layer at its LaO-terminated polar surface.« less

Quantum confinement-induced tunable exciton states in graphene oxide.

PubMed

Lee, Dongwook; Seo, Jiwon; Zhu, Xi; Lee, Jiyoul; Shin, Hyeon-Jin; Cole, Jacqueline M; Shin, Taeho; Lee, Jaichan; Lee, Hangil; Su, Haibin

2013-01-01

Graphene oxide has recently been considered to be a potential replacement for cadmium-based quantum dots due to its expected high fluorescence. Although previously reported, the origin of the luminescence in graphene oxide is still controversial. Here, we report the presence of core/valence excitons in graphene-based materials, a basic ingredient for optical devices, induced by quantum confinement. Electron confinement in the unreacted graphitic regions of graphene oxide was probed by high resolution X-ray absorption near edge structure spectroscopy and first-principles calculations. Using experiments and simulations, we were able to tune the core/valence exciton energy by manipulating the size of graphitic regions through the degree of oxidation. The binding energy of an exciton in highly oxidized graphene oxide is similar to that in organic electroluminescent materials. These results open the possibility of graphene oxide-based optoelectronic device technology.

Defects and Small Polarons on Oxide Surfaces

NASA Astrophysics Data System (ADS)

Janotti, Anderson

The presence and behavior of defects on the surface of oxides are central in many research areas, including catalysis, photochemistry, solar cells, and surface science in general. Experimental characterization of individual defects and their activities are challenging and often requires special preparations of the surface. First-principles calculations based on density functional theory are a powerful tool to study surfaces and defects, often providing information on properties that are difficult to access experimentally. Here we discuss the behavior of defects on oxide surfaces from the perspective on first-principles calculations. We use the oxygen vacancy on TiO2 surface as example, a system that has been extensively reported in the literature. Using DFT with a hybrid function, we discuss surface states induced by the defect and localization of the excess charge in the form of small polarons. We then discuss the effects of hydrogen and compare the behavior of these defects on the surface with that in the bulk. We also compare our recent results with previous theoretical studies and experiments. Finally, we generalize the findings on TiO2 to the surfaces of other oxides. This work was supported by the NSF.

Arsenic in hydrothermal apatite: Oxidation state, mechanism of uptake, and comparison between experiments and nature

NASA Astrophysics Data System (ADS)

Liu, Weihua; Mei, Yuan; Etschmann, Barbara; Brugger, Joël; Pearce, Mark; Ryan, Chris G.; Borg, Stacey; Wykes, Jeremey; Kappen, Peter; Paterson, David; Boesenberg, Ulrike; Garrevoet, Jan; Moorhead, Gareth; Falkenberg, Gerald

2017-01-01

Element substitution that occurs during fluid-rock interaction permits assessment of fluid composition and interaction conditions in ancient geological systems, and provides a way to fix contaminants from aqueous solutions. We conducted a series of hydrothermal mineral replacement experiments to determine whether a relationship can be established between arsenic (As) distribution in apatite and fluid chemistry. Calcite crystals were reacted with phosphate solutions spiked with As(V), As(III), and mixed As(III)/As(V) species at 250 °C and water-saturated pressure. Arsenic-bearing apatite rims formed in several hours, and within 48 h the calcite grains were fully replaced. X-ray Absorption Near-edge Spectroscopy (XANES) data show that As retained the trivalent oxidation state in the fully-reacted apatite grown from solutions containing only As(III). Extended X-ray Fine Spectroscopy (EXAFS) data reveal that these As(III) ions are surrounded by about three oxygen atoms at an Assbnd O bond length close to that of an arsenate group (AsO43-), indicating that they occupy tetrahedral phosphate sites. The three-coordinated As(III)-O3 structure, with three oxygen atoms and one lone electron pair around As(III), was confirmed by geometry optimization using ab initio molecular simulations. The micro-XANES imaging data show that apatite formed from solutions spiked with mixed As(III) and As(V) retained only As(V) after completion of the replacement reaction; in contrast, partially reacted samples revealed a complex distribution of As(V)/As(III) ratios, with As(V) concentrated in the center of the grain and As(III) towards the rim. Most natural apatites from the Ernest Henry iron oxide copper gold deposit, Australia, show predominantly As(V), but two grains retained some As(III) in their core. The As-anomalous amphibolite-facies gneiss from Binntal, Switzerland, only revealed As(V), despite the fact that these apatites in both cases formed under conditions where As(III) is

Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate Ciona intestinalis

EPA Science Inventory

Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+3 oxidation state) methyltransferase (As3mt), yielding mono- , di- , and trimethylated arsenicals. To investigate the evolution of molecular mechanisms that mediate arsenic biotransformation,...

Private Landowner Attitudes Concerning Public Access for Outdoor Recreation: Cultural and Political Factors in the United States

Treesearch

Paul Gentle; John Berhstrom; H. Ken Cordell; Jeff Teasley

1999-01-01

In this article issues concerning national commonalities and regional differences in the United States regarding private land and outdoor recreation are reviewed. Based on the particular cultural and political backgrounds of each region, it is hypothesized that landowners will exhibit degrees of differences in their attitudes regarding public access to private land....

Catalytic process for formaldehyde oxidation

NASA Technical Reports Server (NTRS)

Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)

1996-01-01

Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Structural oxidation state studies of the manganese cluster in the oxygen evolving complex of photosystem II

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

Liang, Wenchuan

X-ray absorption spectroscopy (XAS) was performed on Photosystem II (PSII)-enriched membranes prepared from spinach to explore: (1) the correlation between structure and magnetic spin state of the Mn cluster in the oxygen evolving complex (OEC) in the S 2 state; and (2) the oxidation state changes of the Mn cluster in the flash-induced S-states. The structure of the Mn cluster in the S 2 state with the g~4 electron paramagnetic resonance (EPR) signal (S 2-g4 state) was compared with that in the S 2 state with multiline signal (S 2-MLS state) and the S 1 state. The S 2-g4 statemore » has a higher XAS inflection point energy than that of the S 1 state, indicating the oxidation of Mn in the advance from the S 1 to the S 2-g4 state. Differences in the edge shape and in the extended X-ray absorption fine structure (EXAFS) show that the structure of the Mn cluster in the S 2-g4 state is different from that in the S 2-MLS or the S 1 state. In the S 2-g4 state, the second shell of backscatterers from the Mn absorber contains two Mn-Mn distances of 2.73 Å and 2.85 Å. Very little distance disorder exists in the second shell of the S 1 or S 2-MLS states. The third shell of the S 2-g4 state at about 3.3 Å also contains increased heterogeneity relative to that of the S 2-MLS or the S 1 state. Various S-states were prepared at room-temperature by saturating, single-turnover flashes. The flash-dependent oscillation in the amplitude of the MLS was used to characterize the S-state composition and to construct "pure" S-state Mn K-edge spectra. The edge position shifts to higher energy by 1.8 eV upon the S 1 → S 2 transition.« less

Quantum confinement-induced tunable exciton states in graphene oxide

PubMed Central

Lee, Dongwook; Seo, Jiwon; Zhu, Xi; Lee, Jiyoul; Shin, Hyeon-Jin; Cole, Jacqueline M.; Shin, Taeho; Lee, Jaichan; Lee, Hangil; Su, Haibin

2013-01-01

Graphene oxide has recently been considered to be a potential replacement for cadmium-based quantum dots due to its expected high fluorescence. Although previously reported, the origin of the luminescence in graphene oxide is still controversial. Here, we report the presence of core/valence excitons in graphene-based materials, a basic ingredient for optical devices, induced by quantum confinement. Electron confinement in the unreacted graphitic regions of graphene oxide was probed by high resolution X-ray absorption near edge structure spectroscopy and first-principles calculations. Using experiments and simulations, we were able to tune the core/valence exciton energy by manipulating the size of graphitic regions through the degree of oxidation. The binding energy of an exciton in highly oxidized graphene oxide is similar to that in organic electroluminescent materials. These results open the possibility of graphene oxide-based optoelectronic device technology. PMID:23872608

Quantifying protein interface footprinting by hydroxyl radical oxidation and molecular dynamics simulation: application to galectin-1.

PubMed

Charvátová, Olga; Foley, B Lachele; Bern, Marshall W; Sharp, Joshua S; Orlando, Ron; Woods, Robert J

2008-11-01

Biomolecular surface mapping methods offer an important alternative method for characterizing protein-protein and protein-ligand interactions in cases in which it is not possible to determine high-resolution three-dimensional (3D) structures of complexes. Hydroxyl radical footprinting offers a significant advance in footprint resolution compared with traditional chemical derivatization. Here we present results of footprinting performed with hydroxyl radicals generated on the nanosecond time scale by laser-induced photodissociation of hydrogen peroxide. We applied this emerging method to a carbohydrate-binding protein, galectin-1. Since galectin-1 occurs as a homodimer, footprinting was employed to characterize the interface of the monomeric subunits. Efficient analysis of the mass spectrometry data for the oxidized protein was achieved with the recently developed ByOnic (Palo Alto, CA) software that was altered to handle the large number of modifications arising from side-chain oxidation. Quantification of the level of oxidation has been achieved by employing spectral intensities for all of the observed oxidation states on a per-residue basis. The level of accuracy achievable from spectral intensities was determined by examination of mixtures of synthetic peptides related to those present after oxidation and tryptic digestion of galectin-1. A direct relationship between side-chain solvent accessibility and level of oxidation emerged, which enabled the prediction of the level of oxidation given the 3D structure of the protein. The precision of this relationship was enhanced through the use of average solvent accessibilities computed from 10 ns molecular dynamics simulations of the protein.

Modeling spatial accessibility to parks: a national study.

PubMed

Zhang, Xingyou; Lu, Hua; Holt, James B

2011-05-09

Parks provide ideal open spaces for leisure-time physical activity and important venues to promote physical activity. The spatial configuration of parks, the number of parks and their spatial distribution across neighborhood areas or local regions, represents the basic park access potential for their residential populations. A new measure of spatial access to parks, population-weighted distance (PWD) to parks, combines the advantages of current park access approaches and incorporates the information processing theory and probability access surface model to more accurately quantify residential population's potential spatial access to parks. The PWD was constructed at the basic level of US census geography - blocks - using US park and population data. This new measure of population park accessibility was aggregated to census tract, county, state and national levels. On average, US residential populations are expected to travel 6.7 miles to access their local neighborhood parks. There are significant differences in the PWD to local parks among states. The District of Columbia and Connecticut have the best access to local neighborhood parks with PWD of 0.6 miles and 1.8 miles, respectively. Alaska, Montana, and Wyoming have the largest PWDs of 62.0, 37.4, and 32.8 miles, respectively. Rural states in the western and Midwestern US have lower neighborhood park access, while urban states have relatively higher park access. The PWD to parks provides a consistent platform for evaluating spatial equity of park access and linking with population health outcomes. It could be an informative evaluation tool for health professionals and policy makers. This new method could be applied to quantify geographic accessibility of other types of services or destinations, such as food, alcohol, and tobacco outlets.

Actinide Oxidation State and O/M Ratio in Hypostoichiometric Uranium-Plutonium-Americium U0.750Pu0.246Am0.004O2-x Mixed Oxides.

PubMed

Vauchy, Romain; Belin, Renaud C; Robisson, Anne-Charlotte; Lebreton, Florent; Aufore, Laurence; Scheinost, Andreas C; Martin, Philippe M

2016-03-07

Innovative americium-bearing uranium-plutonium mixed oxides U1-yPuyO2-x are envisioned as nuclear fuel for sodium-cooled fast neutron reactors (SFRs). The oxygen-to-metal (O/M) ratio, directly related to the oxidation state of cations, affects many of the fuel properties. Thus, a thorough knowledge of its variation with the sintering conditions is essential. The aim of this work is to follow the oxidation state of uranium, plutonium, and americium, and so the O/M ratio, in U0.750Pu0.246Am0.004O2-x samples sintered for 4 h at 2023 K in various Ar + 5% H2 + z vpm H2O (z = ∼ 15, ∼ 90, and ∼ 200) gas mixtures. The O/M ratios were determined by gravimetry, XAS, and XRD and evidenced a partial oxidation of the samples at room temperature. Finally, by comparing XANES and EXAFS results to that of a previous study, we demonstrate that the presence of uranium does not influence the interactions between americium and plutonium and that the differences in the O/M ratio between the investigated conditions is controlled by the reduction of plutonium. We also discuss the role of the homogeneity of cation distribution, as determined by EPMA, on the mechanisms involved in the reduction process.

Determination of ground-state hole-transfer rates between equivalent sites in oxidized multiporphyrin arrays using time-resolved optical spectroscopy.

PubMed

Song, Hee-eun; Kirmaier, Christine; Taniguchi, Masahiko; Diers, James R; Bocian, David F; Lindsey, Jonathan S; Holten, Dewey

2008-11-19

Excited-state charge separation in molecular architectures has been widely explored, yet ground-state hole (or electron) transfer, particularly involving equivalent pigments, has been far less studied, and direct quantitation of the rate of transfer often has proved difficult. Prior studies of ground-state hole transfer between equivalent zinc porphyrins using electron paramagnetic resonance techniques give a lower limit of approximately (50 ns)(-1) on the rates. Related transient optical studies of hole transfer between inequivalent sites [zinc porphyrin (Zn) and free base porphyrin (Fb)] give an upper limit of approximately (20 ps)(-1). Thus, a substantial window remains for the unknown rates of ground-state hole transfer between equivalent sites. Herein, the ground-state hole-transfer processes are probed in a series of oxidized porphyrin triads (ZnZnFb) with the focus being on determination of the rates between the nominally equivalent sites (Zn/Zn). The strategy builds upon recent time-resolved optical studies of the photodynamics of dyads wherein a zinc porphyrin is electrochemically oxidized and the attached free base porphyrin is photoexcited. The resulting energy- and hole-transfer processes in the oxidized ZnFb dyads are typically complete within 100 ps of excitation. Such processes are also present in the triads and serve as a starting point for determining the rates of ground-state hole transfer between equivalent sites in the triads. The rate constant of the Zn/Zn hole transfer is found to be (0.8 ns)(-1) for diphenylethyne-linked zinc porphyrins and increases only slightly to (0.6 ns)(-1) when a shorter phenylene linker is utilized. The rate decreases slightly to (1.1 ns)(-1) when steric constraints are introduced in the diarylethyne linker. In general, the rate constants for ground-state Zn/Zn hole transfer in oxidized arrays are a factor of 40 slower than those for Zn/Fb transfer. Collectively, the findings should aid the design of next

Pharmaceutical Market Access: current state of affairs and key challenges – results of the Market Access Launch Excellence Inventory (MALEI)

PubMed Central

Koch, Marcus A.

2015-01-01

Objectives To take inventory of the current state of affairs of Market Access Launch Excellence in the life sciences industry. To identify key gaps and challenges for Market Access (MA) and discuss how they can be addressed. To generate a baseline for benchmarking MA launch excellence. Methodology An online survey was conducted with pharmaceutical executives primarily working in MA, marketing, or general management. The survey aimed to evaluate MA excellence prerequisites across the product life cycle (rated by importance and level of implementation) and to describe MA activity models in the respective companies. Composite scores were calculated from respondents’ ratings and answers. Results Implementation levels of MA excellence prerequisites generally lagged behind their perceived importance. Item importance and the respective level of implementation correlated well, which can be interpreted as proof of the validity of the questionnaire. The following areas were shown to be particularly underimplemented: 1) early integration of MA and health economic considerations in research and development decision making, 2) developing true partnerships with payers, including the development of services ‘beyond the pill’, and 3) consideration of human resource and talent management. The concept of importance-adjusted implementation levels as a hybrid parameter was introduced and shown to be a viable tool for benchmarking purposes. More than 70% of respondents indicated that their companies will invest broadly in MA in terms of capital and headcount within the next 3 years. Conclusions MA (launch) excellence needs to be further developed in order to close implementation gaps across the entire product life cycle. As MA is a comparatively young pharmaceutical discipline in a complex and dynamic environment, this effort will require strategic focus and dedication. The Market Access Launch Excellence Inventory benchmarking tool may help guide decision makers to prioritize

Low-power resistive random access memory by confining the formation of conducting filaments

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

Huang, Yi-Jen; Lee, Si-Chen, E-mail: sclee@ntu.edu.tw; Shen, Tzu-Hsien

2016-06-15

Owing to their small physical size and low power consumption, resistive random access memory (RRAM) devices are potential for future memory and logic applications in microelectronics. In this study, a new resistive switching material structure, TiO{sub x}/silver nanoparticles/TiO{sub x}/AlTiO{sub x}, fabricated between the fluorine-doped tin oxide bottom electrode and the indium tin oxide top electrode is demonstrated. The device exhibits excellent memory performances, such as low operation voltage (<±1 V), low operation power, small variation in resistance, reliable data retention, and a large memory window. The current-voltage measurement shows that the conducting mechanism in the device at the high resistancemore » state is via electron hopping between oxygen vacancies in the resistive switching material. When the device is switched to the low resistance state, conducting filaments are formed in the resistive switching material as a result of accumulation of oxygen vacancies. The bottom AlTiO{sub x} layer in the device structure limits the formation of conducting filaments; therefore, the current and power consumption of device operation are significantly reduced.« less

Markers of Oxidant Stress that are Clinically Relevant in Aging and Age-related Disease

PubMed Central

Jacob, Kimberly D.; Hooten, Nicole Noren; Trzeciak, Andrzej R.; Evans, Michele K.

2013-01-01

Despite the long held hypothesis that oxidant stress results in accumulated oxidative damage to cellular macromolecules and subsequently to aging and age-related chronic disease, it has been difficult to consistently define and specifically identify markers of oxidant stress that are consistently and directly linked to age and disease status. Inflammation because it is also linked to oxidant stress, aging, and chronic disease also plays an important role in understanding the clinical implications of oxidant stress and relevant markers. Much attention has focused on identifying specific markers of oxidative stress and inflammation that could be measured in easily accessible tissues and fluids (lymphocytes, plasma, serum). The purpose of this review is to discuss markers of oxidant stress used in the field as biomarkers of aging and age-related diseases, highlighting differences observed by race when data is available. We highlight DNA, RNA, protein, and lipid oxidation as measures of oxidative stress, as well as other well-characterized markers of oxidative damage and inflammation and discuss their strengths and limitations. We present the current state of the literature reporting use of these markers in studies of human cohorts in relation to age and age-related disease and also with a special emphasis on differences observed by race when relevant. PMID:23428415

Morphological diversity of cassava accessions of the south-central mesoregion of the State of Mato Grosso, Brazil.

PubMed

Zago, B W; Barelli, M A A; Hoogerheide, E S S; Corrêa, C L; Delforno, G I S; da Silva, C J

2017-08-17

Genetic variability of cassava (Manihot esculenta Crantz) in Brazil is wide, being this the result of natural and cultural selection during pre- and post-domestication of the species in different environments. Given the number of species of the genus found in the region (38 of a total of 98 species), the central region of Brazil was defined as the primary center of cassava diversity. Therefore, genetic diversity characterization of cassava accessions is fundamental, both for farmers and for plant breeders, because it allows the organization of genetic resources and better utilization of available genetic diversity. This research aims to assess genetic divergence of cassava accessions from the south-central region of the State of Mato Grosso, based on multi-categorical morphological traits. For this purpose, 38 qualitative and quantitative morphological descriptors were used. Genetic diversity was expressed by the genetic similarity index, with subsequent clustering of accessions by the modified Tocher's procedure and UPGMA. Of 38 descriptors, only growth habit of stem showed no variability. Tocher and UPGMA methods were efficient and corroborated on group composition. Both methods were able to group accessions of different localities in distinct group consistency.

Final-state effect on x-ray photoelectron spectrum of nominally d1 and n -doped d0 transition-metal oxides

NASA Astrophysics Data System (ADS)

Lin, Chungwei; Posadas, Agham; Hadamek, Tobias; Demkov, Alexander A.

2015-07-01

We investigate the x-ray photoelectron spectroscopy (XPS) of nominally d1 and n -doped d0 transition-metal oxides including NbO2,SrVO3, and LaTiO3 (nominally d1), as well as n -doped SrTiO3 (nominally d0). In the case of single phase d1 oxides, we find that the XPS spectra (specifically photoelectrons from Nb 3 d , V 2 p , Ti 2 p core levels) all display at least two, and sometimes three distinct components, which can be consistently identified as d0,d1, and d2 oxidation states (with decreasing order in binding energy). Electron doping increases the d2 component but decreases the d0 component, whereas hole doping reverses this trend; a single d1 peak is never observed, and the d0 peak is always present even in phase-pure samples. In the case of n -doped SrTiO3, the d1 component appears as a weak shoulder with respect to the main d0 peak. We argue that these multiple peaks should be understood as being due to the final-state effect and are intrinsic to the materials. Their presence does not necessarily imply the existence of spatially localized ions of different oxidation states nor of separate phases. A simple model is provided to illustrate this interpretation, and several experiments are discussed accordingly. The key parameter to determine the relative importance between the initial-state and final-state effects is also pointed out.

Pulse I-V characterization of a nano-crystalline oxide device with sub-gap density of states

NASA Astrophysics Data System (ADS)

Kim, Taeho; Hur, Ji-Hyun; Jeon, Sanghun

2016-05-01

Understanding the charge trapping nature of nano-crystalline oxide semiconductor thin film transistors (TFTs) is one of the most important requirements for their successful application. In our investigation, we employed a fast-pulsed I-V technique for understanding the charge trapping phenomenon and for characterizing the intrinsic device performance of an amorphous/nano-crystalline indium-hafnium-zinc-oxide semiconductor TFT with varying density of states in the bulk. Because of the negligible transient charging effect with a very short pulse, the source-to-drain current obtained with the fast-pulsed I-V measurement was higher than that measured by the direct-current characterization method. This is because the fast-pulsed I-V technique provides a charge-trap free environment, suggesting that it is a representative device characterization methodology of TFTs. In addition, a pulsed source-to-drain current versus time plot was used to quantify the dynamic trapping behavior. We found that the charge trapping phenomenon in amorphous/nano-crystalline indium-hafnium-zinc-oxide TFTs is attributable to the charging/discharging of sub-gap density of states in the bulk and is dictated by multiple trap-to-trap processes.

Pulse I-V characterization of a nano-crystalline oxide device with sub-gap density of states.

PubMed

Kim, Taeho; Hur, Ji-Hyun; Jeon, Sanghun

2016-05-27

Understanding the charge trapping nature of nano-crystalline oxide semiconductor thin film transistors (TFTs) is one of the most important requirements for their successful application. In our investigation, we employed a fast-pulsed I-V technique for understanding the charge trapping phenomenon and for characterizing the intrinsic device performance of an amorphous/nano-crystalline indium-hafnium-zinc-oxide semiconductor TFT with varying density of states in the bulk. Because of the negligible transient charging effect with a very short pulse, the source-to-drain current obtained with the fast-pulsed I-V measurement was higher than that measured by the direct-current characterization method. This is because the fast-pulsed I-V technique provides a charge-trap free environment, suggesting that it is a representative device characterization methodology of TFTs. In addition, a pulsed source-to-drain current versus time plot was used to quantify the dynamic trapping behavior. We found that the charge trapping phenomenon in amorphous/nano-crystalline indium-hafnium-zinc-oxide TFTs is attributable to the charging/discharging of sub-gap density of states in the bulk and is dictated by multiple trap-to-trap processes.

[Court-ordered access to treatment of rare genetic diseases: Fabry Disease in the state of Rio Grande do Sul, Brazil].

PubMed

Sartori Junior, Dailor; Leivas, Paulo Gilberto Cogo; Souza, Mônica Vinhas de; Krug, Bárbara Corrêa; Balbinotto, Giacomo; Schwartz, Ida Vanessa Doederlein

2012-10-01

Court-ordered access to high-cost drugs for rare genetic diseases, such as Fabry Disease (alpha-galactosidase-A deficiency), is a growing phenomenon as yet lacking systematic study. An observational, cross-sectional and retrospective study was conducted to characterize the lawsuits related to access to treatment for Fabry Disease by Enzyme Replacement Therapy in the State of Rio Grande do Sul prior to 2007. The study identified 13 lawsuits and 17 plaintiffs, 11 requesting alfa and 6 betagalsidase. The State of RS, the Federal Government, and 5 municipalities figured as defendants, in the form of joinder of parties or otherwise. There were 13 requests for interlocutory relief of which 12 were granted, and 2 sentences were handed down, both favorable. "Risk of death" was alleged by doctors in 4 prescriptions and by lawyers in the 13 lawsuits. The data suggest the lack of discussions combining aspects of medical efficacy and safety, cost-effectiveness, economic impact, and legal and constitutional arguments, which requires a specific policy for rare genetic diseases to standardize access to treatment.

Associations between state minimum wage policy and health care access: a multi-level analysis of the 2004 Behavioral Risk Factor survey.

PubMed

McCarrier, Kelly P; Martin, Diane P; Ralston, James D; Zimmerman, Frederick J

2010-05-01

Minimum wage policies have been advanced as mechanisms to improve the economic conditions of the working poor. Both positive and negative effects of such policies on health care access have been hypothesized, but associations have yet to be thoroughly tested. To examine whether the presence of minimum wage policies in excess of the federal standard of $5.15 per hour was associated with health care access indicators among low-skilled adults of working age, a cross-sectional analysis of 2004 Behavioral Risk Factor Surveillance System data was conducted. Self-reported health insurance status and experience with cost-related barriers to needed medical care were adjusted in multi-level logistic regression models to control for potential confounding at the state, county, and individual levels. State-level wage policy was not found to be associated with insurance status or unmet medical need in the models, providing early evidence that increased minimum wage rates may neither strengthen nor weaken access to care as previously predicted.

Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate Ciona intestinalis

EPA Science Inventory

The biotransformation of inorganic arsenic (iAs) involves methylation by an arsenic (+3 oxidation state) methyltransferase (AS3MT), yielding methyl arsenic (MA), dimethyl arsenic (DMA), and trimethylarsenic (TMA). To identify molecular mechanisms that coordinate arsenic biotra...

Compliance with youth access regulations for indoor UV tanning.

PubMed

Hester, Eric J; Heilig, Lauren F; D'Ambrosia, Renee; Drake, Amanda L; Schilling, Lisa M; Dellavalle, Robert P

2005-08-01

To describe youth access to indoor UV tanning and youth discount pricing incentives in 4 states with different age restrictions: Colorado (no age restrictions), Texas (age 13 years), Illinois (age 14 years), and Wisconsin (age 16 years). Cross-sectional telephone survey conducted in October 2003 using a standardized script to assess the practices of randomly selected UV tanning operators. Randomly selected licensed indoor UV tanning facility operators in Colorado, Texas, Illinois, and Wisconsin. Number of facilities (1) complying with indoor UV tanning minimum age regulations for a 12-year-old potential patron and a 15-year-old potential patron and (2) offering youth discounts. For a 12-year-old potential patron, 62% of facilities in states with minimum age restrictions prohibiting 12-year-olds had an operator report that they would not permit indoor tanning (Texas, 23%; Illinois, 74%; and Wisconsin, 89%) compared with 18% in Colorado, a state without youth access regulations. For a 15-year-old patron, most facilities in Wisconsin, the only state with a minimum age restriction for 15-year-olds, prohibited access (77%). Overall, 15% of operators offered youth discounts: Texas, 23%; Illinois, 14%; Wisconsin, 11%; and Colorado, 11%. Tanning facilities in 4 states offered price incentives directed at youths. State youth access regulations were associated with decreased youth access to indoor tanning. High compliance levels in states with long-standing youth access regulations (Illinois and Wisconsin) demonstrate the potential for successful tanning industry youth access regulation.

Racial/Ethnic Disparities in Chronic Diseases of Youths and Access to Health Care in the United States

PubMed Central

Price, James H.; Braun, Robert

2013-01-01

Racial/ethnic minorities are 1.5 to 2.0 times more likely than whites to have most of the major chronic diseases. Chronic diseases are also more common in the poor than the nonpoor and this association is frequently mediated by race/ethnicity. Specifically, children are disproportionately affected by racial/ethnic health disparities. Between 1960 and 2005 the percentage of children with a chronic disease in the United States almost quadrupled with racial/ethnic minority youth having higher likelihood for these diseases. The most common major chronic diseases of youth in the United States are asthma, diabetes mellitus, obesity, hypertension, dental disease, attention-deficit/hyperactivity disorder, mental illness, cancers, sickle-cell anemia, cystic fibrosis, and a variety of genetic and other birth defects. This review will focus on the psychosocial rather than biological factors that play important roles in the etiology and subsequent solutions to these health disparities because they should be avoidable and they are inherently unjust. Finally, this review examines access to health services by focusing on health insurance and dental insurance coverage and access to school health services. PMID:24175301

Quantitative evaluation of the effect of H2O degassing on the oxidation state of magmas

NASA Astrophysics Data System (ADS)

Lange, R. A.; Waters, L.

2014-12-01

The extent to which degassing of the H2O component affects the oxidation state of hydrous magmas is widely debated. Several researchers have examined how degassing of mixed H-C-O-S-Cl fluids may change the Fe3+/FeT ratio of various magmas, whereas our focus is on the H2O component. There are two ways that degassing of H2O by itself may cause oxidation: (1) the reaction: H2O (melt) + 2FeO (melt) = H2 (fluid) + Fe2O3 (melt), and/or (2) if dissolved water preferentially enhances the activity of ferrous vs. ferric iron in magmatic liquids. In this study, a comparison is made between the pre-eruptive oxidation states of 14 crystal-poor, jet-black obsidian samples (obtained from two Fe-Ti oxides) and their post-eruptive values (analyzed with the Wilson 1960 titration method tested against USGS standards). The obsidians are from Medicine Lake (CA), Long Valley (CA), and the western Mexican arc; all have low FeOT (1.1-2.1 wt%), rendering their Fe2+/Fe3+ ratios highly sensitive to the possible effects of substantial H2O degassing. The Fe-Ti oxide thermometer/oxybarometer of Ghiorso and Evans, (2008) gave temperatures for the 14 samples that range for 720 to 940°C and ΔNNO values of -0.9 to +1.4. With temperature known, the plagioclase-liquid hygrometer was applied and show that ≤ 6.5 wt% H2O was dissolved in the melts prior to eruption. In addition, pre-eruptive Cl and S concentrations were constrained on the basis of apatite analyses (Webster et al., 2009) and sulfur concentrations needed for saturation with pyrrhotite (Clemente et al., 2004), respectively. Maximum pre-eruptive chlorine and sulfur contents are 6000 and 200 ppm, respectively. After eruption, the rhyolites lost nearly all of their volatiles. Our results indicate no detectable change between pre- and post-eruptive Fe2+ concentrations, with an average deviation of ± 0.1 wt % FeO. Although degassing of large concentrations of S and/or Cl may affect the oxidation state of magmas, at the pre-eruptive levels

User Access | Energy Systems Integration Facility | NREL

Science.gov Websites

User Access User Access The ESIF houses an unparalleled collection of state-of-the-art capabilities user access program, the ESIF allows researchers access to its premier laboratories in support of research and development that aims to optimize our entire energy system at full power. Requests for access

Accessing ultrahigh-pressure, quasi-isentropic states of mattera)

NASA Astrophysics Data System (ADS)

Lorenz, K. T.; Edwards, M. J.; Glendinning, S. G.; Jankowski, A. F.; McNaney, J.; Pollaine, S. M.; Remington, B. A.

2005-05-01

A new approach to the study of material strength of metals at extreme pressures has been developed on the Omega laser, using a ramped plasma piston drive. The laser drives a shock through a solid plastic reservoir that unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, inferred from interferometric measurements of velocity, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation [J. Edwards et al., Phys. Rev. Lett. 92, 075002 (2004)]. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor unstable interfaces. This paper reports the first attempt to use this new laser-driven, quasi-isentropic technique for determining material strength in high-pressure solids. Modulated foils of Al-6061-T6 were accelerated and compressed to peak pressures of ˜200kbar. Modulation growth was recorded at a series of times after peak acceleration and well into the release phase. Fits to the growth data, using a Steinberg-Guinan constitutive strength model, give yield strengths 38% greater than those given by the nominal parameters for Al-6061-T6. Calculations indicate that the dynamic enhancement to the yield strength at ˜200kbar is a factor of ˜3.6× over the ambient yield strength of 2.9kbar. Experimental designs based on this drive developed for the National Ignition Facility laser [W. Hogan, E. Moses, B. Warner, M. Sorem, and J. Soures, Nuclear Fusion 41, 567 (2001)] predict that solid-state samples can be quasi-isentropically driven to pressures an order of magnitude higher than on Omega, accessing new regimes of dense, high-pressure matter.

Oxidative Stress State Is Associated with Left Ventricular Mechanics Changes, Measured by Speckle Tracking in Essential Hypertensive Patients.

PubMed

Moreno-Ruíz, Luis Antonio; Ibarra-Quevedo, David; Rodríguez-Martínez, Erika; Maldonado, Perla D; Sarabia-Ortega, Benito; Hernández-Martínez, José Gustavo; Espinosa-Caleti, Beda; Mendoza-Pérez, Beatriz; Rivas-Arancibia, Selva

2015-01-01

The oxidative stress state is characterized by an increase in oxygen reactive species that overwhelms the antioxidant defense; we do not know if these pathological changes are correlated with alterations in left ventricular mechanics. The aim was correlating the oxidative stress state with the left ventricular global longitudinal strain (GLS) and the left ventricular end diastolic pressure (LVEDP). Twenty-five patients with essential hypertension and 25 controls paired by age and gender were studied. All of the participants were subjected to echocardiography and biochemical determination of oxidative stress markers. The hypertensive patients, compared with control subjects, had significantly (p < 0.05) higher levels of oxidized proteins (5.03 ± 1.05 versus 4.06 ± 0.63 nmol/mg), lower levels of extracellular superoxide dismutase (EC-SOD) activity (0.045 ± 0.02 versus 0.082 ± 0.02 U/mg), higher LVEDP (16.2 ± 4.5 versus 11.3 ± 1.6 mm Hg), and lower GLS (-12% versus -16%). Both groups had preserved ejection fraction and the results showed a positive correlation of oxidized proteins with GLS (r = 0.386, p = 0.006) and LVEDP (r = 0.389, p = 0.005); we also found a negative correlation of EC-SOD activity with GLS (r = -0.404, p = 0.004) and LVEDP (r = -0.347, p = 0.014).

A culture gap in the United States: Implications for policy on limiting access to firearms for suicidal persons.

PubMed

Marino, Elizabeth; Wolsko, Christopher; Keys, Susan G; Pennavaria, Laura

2016-09-01

Suicide is a critical public health problem worldwide. In the United States (US), firearm ownership is common, and firearms account for the majority of deaths by suicide. While suicide prevention strategies may include limiting access to firearms, the contentious nature of gun regulations in the US, particularly among members of rural communities, often gives rise to constitutional concerns and political polarization that could inhibit suicidal persons from seeking the help they need. We examine potential outcomes of public health strategies in the US that encourage limiting access to firearms for populations who both value firearm ownership and are vulnerable to suicide. Based on preliminary results from a firearm safety study, we argue that attempts to limit access to firearms among those at risk of suicide will only succeed when the most affected cultural groups are engaged in collaborative discussions.

*Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate ciona intestinalis

EPA Science Inventory

Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+3 oxidation state) methyltransferase (As3mt) , yielding mono-, di-, and trimethylated arsenicals. A comparative genomic approach focused on Ciona intestinaJis, an invertebrate chordate, was u...

Surface states and annihilation characteristics of positrons trapped at the oxidized Cu(100) surface

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Weiss, A. H.

2013-06-01

In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. Oxidation of the Cu(100) surface has been studied by performing an ab-initio investigation of the stability and electronic structure of the Cu(100) missing row reconstructed surface at various on-surface and subsurface oxygen coverages ranging from 0.5 to 1.5 monolayers using density functional theory (DFT). All studied structures have been found to be energetically more favorable as compared to structures formed by purely on-surface oxygen adsorption. The observed decrease in the positron work function when oxygen atoms occupy on-surface and subsurface sites has been attributed to a significant charge redistribution within the first two layers, buckling effects within each layer and an interlayer expansion. The computed positron binding energy, positron surface state wave function, and annihilation probabilities of the surface trapped positrons with relevant core electrons demonstrate their sensitivity to oxygen coverage, atomic structure of the topmost layers of surfaces, and charge transfer effects. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES). The results presented provide an explanation for the changes observed in the probability of annihilation of surface trapped positrons with Cu 3p core-level electrons as a function of annealing temperature.

Origin of stabilization and destabilization in solid-state redox reaction of oxide ions for lithium-ion batteries

PubMed Central

Yabuuchi, Naoaki; Nakayama, Masanobu; Takeuchi, Mitsue; Komaba, Shinichi; Hashimoto, Yu; Mukai, Takahiro; Shiiba, Hiromasa; Sato, Kei; Kobayashi, Yuki; Nakao, Aiko; Yonemura, Masao; Yamanaka, Keisuke; Mitsuhara, Kei; Ohta, Toshiaki

2016-01-01

Further increase in energy density of lithium batteries is needed for zero emission vehicles. However, energy density is restricted by unavoidable theoretical limits for positive electrodes used in commercial applications. One possibility towards energy densities exceeding these limits is to utilize anion (oxide ion) redox, instead of classical transition metal redox. Nevertheless, origin of activation of the oxide ion and its stabilization mechanism are not fully understood. Here we demonstrate that the suppression of formation of superoxide-like species on lithium extraction results in reversible redox for oxide ions, which is stabilized by the presence of relatively less covalent character of Mn4+ with oxide ions without the sacrifice of electronic conductivity. On the basis of these findings, we report an electrode material, whose metallic constituents consist only of 3d transition metal elements. The material delivers a reversible capacity of 300 mAh g−1 based on solid-state redox reaction of oxide ions. PMID:28008955

Origin of stabilization and destabilization in solid-state redox reaction of oxide ions for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Yabuuchi, Naoaki; Nakayama, Masanobu; Takeuchi, Mitsue; Komaba, Shinichi; Hashimoto, Yu; Mukai, Takahiro; Shiiba, Hiromasa; Sato, Kei; Kobayashi, Yuki; Nakao, Aiko; Yonemura, Masao; Yamanaka, Keisuke; Mitsuhara, Kei; Ohta, Toshiaki

2016-12-01

Further increase in energy density of lithium batteries is needed for zero emission vehicles. However, energy density is restricted by unavoidable theoretical limits for positive electrodes used in commercial applications. One possibility towards energy densities exceeding these limits is to utilize anion (oxide ion) redox, instead of classical transition metal redox. Nevertheless, origin of activation of the oxide ion and its stabilization mechanism are not fully understood. Here we demonstrate that the suppression of formation of superoxide-like species on lithium extraction results in reversible redox for oxide ions, which is stabilized by the presence of relatively less covalent character of Mn4+ with oxide ions without the sacrifice of electronic conductivity. On the basis of these findings, we report an electrode material, whose metallic constituents consist only of 3d transition metal elements. The material delivers a reversible capacity of 300 mAh g-1 based on solid-state redox reaction of oxide ions.

cis Retinol oxidation regulates photoreceptor access to the retina visual cycle and cone pigment regeneration

PubMed Central

Sato, Shinya

2016-01-01

Key points This study explores the nature of the cis retinol that Müller cells in the retina provide to cones for the regeneration of their visual pigment.We report that the retina visual cycle provides cones exclusively with 11‐cis chromophore in both salamander and mouse and show that this selectivity is dependent on the 11‐cis‐specific cellular retinaldehyde binding protein (CRALBP) present in Müller cells.Even though salamander blue cones and green rods share the same visual pigment, only blue cones but not green rods are able to dark‐adapt in the retina following a bleach and to use exogenous 9‐cis retinol for pigment regeneration, suggesting that access to the retina visual cycle is cone‐specific and pigment‐independent.Our results show that the retina produces 11‐cis retinol that can be oxidized and used for pigment regeneration and dark adaptation selectively in cones and not in rods. Abstract Chromophore supply by the retinal Müller cells (retina visual cycle) supports the efficient pigment regeneration required for cone photoreceptor function in bright light. Surprisingly, a large fraction of the chromophore produced by dihydroceramide desaturase‐1, the putative all‐trans retinol isomerase in Müller cells, appears to be 9‐cis retinol. In contrast, the canonical retinal pigment epithelium (RPE) visual cycle produces exclusively 11‐cis retinal. Here, we used the different absorption spectra of 9‐cis and 11‐cis pigments to identify the isoform of the chromophore produced by the visual cycle of the intact retina. We found that the spectral sensitivity of salamander and mouse cones dark‐adapted in the isolated retina (with only the retina visual cycle) was similar to that of cones dark‐adapted in the intact eye (with both the RPE and retina visual cycles) and consistent with pure 11‐cis pigment composition. However, in mice lacking the cellular retinaldehyde binding protein (CRALBP), cone spectral sensitivity contained a

Public Access Policy and Communications | DOE PAGES

Science.gov Websites

Close Clear All Find DOE PAGES Public Access Policy and Communications Public Access Policy and Communications 7/24/14 Department of Energy Public Access Plan DOE Public Access Plan 2/22/13 White House Office Information (ICSTI) Insights article Public Access at the United States Department of Energy (1,011 KB), by

Low oxidation state aluminum-containing cluster anions: Cp{sup ∗}Al{sub n}H{sup −}, n = 1–3

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

Zhang, Xinxing; Ganteför, Gerd; Bowen, Kit, E-mail: AKandalam@wcupa.edu, E-mail: kbowen@jhu.edu

Three new, low oxidation state, aluminum-containing cluster anions, Cp*Al{sub n}H{sup −}, n = 1–3, were prepared via reactions between aluminum hydride cluster anions, Al{sub n}H{sub m}{sup −}, and Cp*H ligands. These were characterized by mass spectrometry, anion photoelectron spectroscopy, and density functional theory based calculations. Agreement between the experimentally and theoretically determined vertical detachment energies and adiabatic detachment energies validated the computed geometrical structures. Reactions between aluminum hydride cluster anions and ligands provide a new avenue for discovering low oxidation state, ligated aluminum clusters.

22 CFR 1600.149 - Program accessibility: Discrimination prohibited.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Program accessibility: Discrimination prohibited. 1600.149 Section 1600.149 Foreign Relations JAPAN-UNITED STATES FRIENDSHIP COMMISSION ENFORCEMENT... STATES FRIENDSHIP COMMISSION § 1600.149 Program accessibility: Discrimination prohibited. Except as...

NiMn layered double hydroxide nanosheets/NiCo2O4 nanowires with surface rich high valence state metal oxide as an efficient electrocatalyst for oxygen evolution reaction

NASA Astrophysics Data System (ADS)

Yang, Liting; Chen, Lin; Yang, Dawen; Yu, Xu; Xue, Huaiguo; Feng, Ligang

2018-07-01

High valence transition metal oxide is significant for anode catalyst of proton membrane water electrolysis technique. Herein, we demonstrate NiMn layered double hydroxide nanosheets/NiCo2O4 nanowires hierarchical nanocomposite catalyst with surface rich high valence metal oxide as an efficient catalyst for oxygen evolution reaction. A low overpotential of 310 mV is needed to drive a 10 mA cm-2 with a Tafel slope of 99 mV dec-1, and a remarkable stability during 8 h is demonstrated in a chronoamperometry test. Theoretical calculation displays the change in the rate-determining step on the nanocomposite electrode in comparison to NiCo2O4 nanowires alone. It is found high valence Ni and Mn oxide in the catalyst system can efficiently facilitate the charge transport across the electrode/electrolyte interface. The enhanced electrical conductivity, more accessible active sites and synergistic effects between NiMn layered double hydroxide nanosheets and NiCo2O4 nanowires can account for the excellent oxygen evolution reaction. The catalytic performance is comparable to most of the best non-noble catalysts and IrO2 noble catalyst, indicating the promising applications in water-splitting technology. It is an important step in the development of hierarchical nanocomposites by surface valence state tuning as an alternative to noble metals for oxygen evolution reaction.

Metabolism of Nitrogen Oxides in Ammonia-Oxidizing Bacteria

NASA Astrophysics Data System (ADS)

Kozlowski, J.; Stein, L. Y.

2014-12-01

Ammonia-oxidizing bacteria (AOB) are key microorganisms in the transformation of nitrogen intermediates in most all environments. Until recently there was very little work done to elucidate the physiology of ammonia-oxidizing bacteria cultivated from variable trophic state environments. With a greater variety of ammonia-oxidizers now in pure culture the importance of comparative physiological and genomic analysis is crucial. Nearly all known physiology of ammonia-oxidizing bacteria lies within the Nitrosomonas genus with Nitrosomonas europaea strain ATCC 19718 as the model. To more broadly characterize and understand the nature of obligate ammonia chemolithotrophy and the contribution of AOB to production of nitrogen oxides, Nitrosomonas spp. and Nitrosospira spp. isolated from variable trophic states and with sequenced genomes, were utilized. Instantaneous ammonia- and hydroxylamine-oxidation kinetics as a function of oxygen and substrate concentration were measured using an oxygen micro-sensor. The pathway intermediates nitric oxide and nitrous oxide were measured in real time using substrate-specific micro-sensors to elucidate whether production of these molecules is stoichiometric with rates of substrate oxidation. Genomic inventory was compared among the strains to identify specific pathways and modules to explain physiological differences in kinetic rates and production of N-oxide intermediates as a condition of their adaptation to different ammonium concentrations. This work provides knowledge of how nitrogen metabolism is differentially controlled in AOB that are adapted to different concentrations of ammonium. Overall, this work will provide further insight into the control of ammonia oxidizing chemolithotrophy across representatives of the Nitrosomonas and Nitrosospira genus, which can then be applied to examine additional genome-sequenced AOB isolates.

Bolide impacts and the oxidation state of carbon in the Earth's early atmosphere

NASA Technical Reports Server (NTRS)

Kasting, J. F.

1992-01-01

A one-dimensional photochemical model was used to examine the effect of bolide impacts on the oxidation state of Earth's primitive atmosphere. The impact rate should have been high prior to 3.8 Ga before present, based on evidence derived from the Moon. Impacts of comets or carbonaceous asteroids should have enhanced the atmospheric CO/CO2 ratio by bringing in CO ice and/or organic carbon that can be oxidized to CO in the impact plume. Ordinary chondritic impactors would contain elemental iron that could have reacted with ambient CO2 to give CO. Nitric oxide (NO) should also have been produced by reaction between ambient CO2 and N2 in the hot impact plumes. High NO concentrations increase the atmospheric CO/CO2 ratio by increasing the rainout rate of oxidized gases. According to the model, atmospheric CO/CO2 ratios of unity or greater are possible during the first several hundred million years of Earth's history, provided that dissolved CO was not rapidly oxidized to bicarbonate in the ocean. Specifically, high atmospheric CO/CO2 ratios are possible if either: (1) the climate was cool (like today's climate), so that hydration of dissolved CO to formate was slow, or (2) the formate formed from CO was efficiently converted into volatile, reduced carbon compounds, such as methane. A high atmospheric CO/CO2 ratio may have helped to facilitate prebiotic synthesis by enhancing the production rates of hydrogen cyanide and formaldehyde. Formaldehyde may have been produced even more efficiently by photochemical reduction of bicarbonate and formate in Fe(++)-rich surface waters.

The x ray microprobe determination of chromium oxidation state in olivine from lunar basalt and kimberlitic diamonds

NASA Technical Reports Server (NTRS)

Sutton, S. R.; Bajt, S.; Rivers, M. L.; Smith, J. V.

1993-01-01

The synchrotron x-ray microprobe is being used to obtain oxidation state information on planetary materials with high spatial resolution. Initial results on chromium in olivine from various sources including laboratory experiments, lunar basalt, and kimberlitic diamonds are reported. The lunar olivine was dominated by Cr(2+) whereas the diamond inclusions had Cr(2+/Cr(3+) ratios up to about 0.3. The simpliest interpretation is that the terrestrial olivine crystallized in a more oxidizing environment than the lunar olivine.

34 CFR Appendix A to Subpart C of... - Grants for Access and Persistence Program (GAP) State Grant Allotment Case Study

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Grants for Access and Persistence Program (GAP) State Grant Allotment Case Study A Appendix A to Subpart C of Part 692 Education Regulations of the Offices of...) State Grant Allotment Case Study ER29OC09.010 ER29OC09.011 ER29OC09.012 ER29OC09.013 ER29OC09.014...

The Concept of Oxidation States in Metal Complexes

ERIC Educational Resources Information Center

Steinborn, Dirk

2004-01-01

The concepts of oxidation numbers when applied means electrons that are shared between atoms in molecules are assigned to a specific atom. Oxidation numbers are assigned from the Lewis structure of a molecule, with knowledge of the electronegativities of elements.

Private sector participation in delivering tertiary health care: a dichotomy of access and affordability across two Indian states.

PubMed

Katyal, Anuradha; Singh, Prabal Vikram; Bergkvist, Sofi; Samarth, Amit; Rao, Mala

2015-03-01

Poor quality care in public sector hospitals coupled with the costs of care in the private sector have trapped India's poor in a vicious cycle of poverty, ill health and debt for many decades. To address this, the governments of Andhra Pradesh (AP) and Maharashtra (MH), India, have attempted to improve people's access to hospital care by partnering with the private sector. A number of government-sponsored schemes with differing specifications have been launched to facilitate this strategy. This article aims to compare changes in access to, and affordability and efficiency of private and public hospital inpatient (IP) treatments between MH and AP from 2004 to 2012 and to assess whether the health financing innovations in one state resulted in larger or smaller benefits compared with the other. We used data from household surveys conducted in 2004 and 2012 in the two states and undertook a difference-in-difference (DID) analysis. The results focus on hospitalization, out-of-pocket expenditure and length of stay. The average IP expenditure for private hospital care has increased in both states, but more so in MH. There was also an observable increase in both utilization of and expenditure on nephrology treatment in private hospitals in AP. The duration of stay recorded in days for private hospitals has increased slightly in MH and declined in AP with a significant DID. The utilization of public hospitals has reduced in AP and increased in MH. The state of AP appears to have benefited more than MH in terms of improved access to care by involving the private sector. The Aarogyasri scheme is likely to have contributed to these impacts in AP at least in part. Our study needs to be followed up with repeated evaluations to ascertain the long-term impacts of involving the private sector in providing hospital care. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine © The Author 2015; all rights reserved.

Improving Access to Malaria Rapid Diagnostic Test in Niger State, Nigeria: An Assessment of Implementation up to 2013

PubMed Central

Awoleye, Olatunji Joshua; Thron, Chris

2016-01-01

Nigeria's 2009–2013 malaria strategic plan adopted WHO diagnosis and treatment guidelines, which include the use of rapid diagnostic tests (RDTs) prior to prescribing treatment with artemisinin combination therapies (ACTs). The current study explores accessibility barriers to the use of RDTs in Niger State and makes recommendations for improving the uptake of RDTs. The study employs literature review, review of data from the Niger State Health Management Information System for January–October 2013, and application of Peters' conceptual framework for assessing access to health services. Data showed that 27 percent of public health facilities (HFs) implemented RDTs, with the aid of donor funds. In these facilities, 77 percent of fever cases presented during the study period were tested with RDTs; 53 percent of fever cases were confirmed cases of malaria, while 60 percent of fever cases were treated. Stockouts of RDTs were a major constraint, and severe fever tended to trigger presumptive treatment. We conclude that although implementation of RDTs led to a reduction in the use of ACTs at HFs, more substantial reduction could be achieved if the state government directed more resources towards the acquisition of RDTs as well as raising the level of awareness of potential users. PMID:27042376

Update on Virginia College Access Provider Activity

ERIC Educational Resources Information Center

Corning, Amy; Senechal, Jesse; Hutton, Amy

2015-01-01

In the fall of 2008, the State Council of Higher Education for Virginia (SCHEV) commissioned a research study comparing the college access provider resources in Virginia to the access and academic achievement needs of the state. That study--conducted by researchers from the College of William and Mary and West Carolina University--resulted in the…

34 CFR 300.172 - Access to instructional materials.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CHILDREN WITH DISABILITIES State Eligibility Other Provisions Required for State Eligibility § 300.172... that children with disabilities who need instructional materials in accessible formats, but are not... this section to ensure that children with disabilities who need instructional materials in accessible...

34 CFR 300.172 - Access to instructional materials.

Code of Federal Regulations, 2010 CFR

2010-07-01

... CHILDREN WITH DISABILITIES State Eligibility Other Provisions Required for State Eligibility § 300.172... that children with disabilities who need instructional materials in accessible formats, but are not... this section to ensure that children with disabilities who need instructional materials in accessible...

34 CFR 300.172 - Access to instructional materials.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CHILDREN WITH DISABILITIES State Eligibility Other Provisions Required for State Eligibility § 300.172... that children with disabilities who need instructional materials in accessible formats, but are not... this section to ensure that children with disabilities who need instructional materials in accessible...

34 CFR 300.172 - Access to instructional materials.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CHILDREN WITH DISABILITIES State Eligibility Other Provisions Required for State Eligibility § 300.172... that children with disabilities who need instructional materials in accessible formats, but are not... this section to ensure that children with disabilities who need instructional materials in accessible...

34 CFR 300.172 - Access to instructional materials.

Code of Federal Regulations, 2012 CFR

2012-07-01

... CHILDREN WITH DISABILITIES State Eligibility Other Provisions Required for State Eligibility § 300.172... that children with disabilities who need instructional materials in accessible formats, but are not... this section to ensure that children with disabilities who need instructional materials in accessible...

What Does Role-Based Access Look Like? Examples from States

ERIC Educational Resources Information Center

Data Quality Campaign, 2008

2008-01-01

Data are only useful if people are able to access, understand and use them. Without access to the right information, stakeholders are forced to make decisions based on anecdote, experience or instinct. For information to be useful, it must be timely, readily available, and easy to understand. Different stakeholders need and are entitled to access…

Enhanced catalytic hydrogenation activity of Ni/reduced graphene oxide nanocomposite prepared by a solid-state method

NASA Astrophysics Data System (ADS)

Li, Yizhao; Cao, Yali; Jia, Dianzeng

2018-01-01

A simple solid-state method has been applied to synthesize Ni/reduced graphene oxide (Ni/rGO) nanocomposite under ambient condition. Ni nanoparticles with size of 10-30 nm supported on reduced graphene oxide (rGO) nanosheets are obtained through one-pot solid-state co-reduction among nickel chloride, graphene oxide, and sodium borohydride. The Ni/rGO nanohybrid shows enhanced catalytic activity toward the reduction of p-nitrophenol (PNP) into p-aminophenol compared with Ni nanoparticles. The results of kinetic research display that the pseudo-first-order rate constant for hydrogenation reaction of PNP with Ni/rGO nanocomposite is 7.66 × 10-3 s-1, which is higher than that of Ni nanoparticles (4.48 × 10-3 s-1). It also presents superior turnover frequency (TOF, 5.36 h-1) and lower activation energy ( E a, 29.65 kJ mol-1) in the hydrogenation of PNP with Ni/rGO nanocomposite. Furthermore, composite catalyst can be magnetically separated and reused for five cycles. The large surface area and high electron transfer property of rGO support are beneficial for good catalytic performance of Ni/rGO nanocomposite. Our study demonstrates a simple approach to fabricate metal-rGO heterogeneous nanostructures with advanced functions.

Public Perception of the Millennium Development Goals on Access to Safe Drinking Water in Cross River State, Nigeria

ERIC Educational Resources Information Center

Eni, David D.; Ojong, William M.

2014-01-01

This study evaluated the public perception of Millennium Development Goals (MDGs) of environmental sustainability with focus on the MDG target which has to do with reducing the proportion of people without access to safe drinking water in Cross River State, Nigeria. The stratified and systematic sampling techniques were adopted for the study,…

“It’s Like a Phantom Disease”: Patient Perspectives on Access to Treatment for Chagas Disease in the United States

PubMed Central

Forsyth, Colin J.; Hernandez, Salvador; Flores, Carmen A.; Roman, Mario F.; Nieto, J. Maribel; Marquez, Grecia; Sequeira, Juan; Sequeira, Harry; Meymandi, Sheba K.

2018-01-01

Abstract. Chagas disease (CD) affects > 6 million people globally, including > 300,000 in the United States. Although early detection and etiological treatment prevents chronic complications from CD, < 1% of U.S. cases have been diagnosed and treated. This study explores access to etiological treatment from the perspective of patients with CD. In semi-structured interviews with 50 Latin American–born patients of the Center of Excellence for Chagas Disease at the Olive View–UCLA Medical Center, we collected demographic information and asked patients about their experiences managing the disease and accessing treatment. Patients were highly marginalized, with 63.4% living below the U.S. poverty line, 60% lacking a high school education, and only 12% with private insurance coverage. The main barriers to accessing health care for CD were lack of providers, precarious insurance coverage, low provider awareness, transportation difficulties, and limited time off. Increasing access to diagnosis and treatment will not only require a dramatic increase in provider and public education, but also development of programs which are financially, linguistically, politically, and geographically accessible to patients. PMID:29380723

Effects of photochemical oxidation on the mixing state and light absorption of black carbon in the urban atmosphere of China

NASA Astrophysics Data System (ADS)

Wang, Qiyuan; Huang, Rujin; Zhao, Zhuzi; Cao, Junji; Ni, Haiyan; Tie, Xuexi; Zhu, Chongshu; Shen, Zhenxing; Wang, Meng; Dai, Wenting; Han, Yongming; Zhang, Ningning; Prévôt, André S. H.

2017-04-01

The relationship between the refractory black carbon (rBC) aerosol mixing state and the atmospheric oxidation capacity was investigated to assess the possible influence of oxidants on the particles’ light absorption effects at two large cities in China. The number fraction of thickly-coated rBC particles (F rBC) was positively correlated with a measure of the oxidant concentrations (OX = O3 + NO2), indicating an enhancement of coated rBC particles under more oxidizing conditions. The slope of a linear regression of F rBC versus OX was 0.58% ppb-1 for Beijing and 0.84% ppb-1 for Xi’an, and these relationships provide some insights into the evolution of rBC mixing state in relation to atmospheric oxidation processes. The mass absorption cross-section of rBC (MACrBC) increased with OX during the daytime at Xi’an, at a rate of 0.26 m2 g-1 ppb-1, suggesting that more oxidizing conditions lead to internal mixing that enhances the light-absorbing capacity of rBC particles. Understanding the dependence of the increasing rates of F rBC and MACrBC as a function of OX may lead to improvements of climate models that deal with the warming effects, but more studies in different cities and seasons are needed to gauge the broader implications of these findings.

Upper and Lower Limits of the Rate of SO2 Oxidation In Wintertime Atmosphere Over The Eastern United States

NASA Astrophysics Data System (ADS)

Green, J. R.; Fiddler, M. N.; Brown, S. S.; Bililign, S.; Jaegle, L.; Thornton, J. A.; Shah, V.; Lopez-Hilfiker, F.; Haskins, J.; Fibiger, D. L.; McDuffie, E. E.; Sparks, T.; Ebben, C. J.; Wooldridge, P. J.; Veres, P. R.; Weinheimer, A. J.; Dibb, J. E.; Schroder, J. C.; Campuzano-Jost, P.; Day, D.; Jimenez, J. L.; Sullivan, A.; DiGangi, J. P.

2017-12-01

A set of constraints on the rate of oxidation of SO2 during wintertime conditions over the Eastern United States is presented, based on measurements taken during a series of night and day flights on a C-130 aircraft from Feb 3 to Mar 13, 2015 over the Eastern coastal region of the United States during the Wintertime INvestigation of Transport, Emission and Reactivity (WINTER) campaign. In the Eastern United States, there are fewer reactant sinks for gaseous SO2 during the winter, and as a result the atmospheric lifetime is measurably longer. Photochemical oxidation of SO2 is extremely slow during winter due to significantly reduced OH concentrations compared to summer. The long photochemical lifetime enables analysis of rates of proposed alternative sulfur oxidation mechanisms, such as heterogeneous uptake. An examination of the SO4/SO2 ratio and the mixing ratio will be used to determine the upper and lower limits of the rate of SO2 oxidation, along with the branching ratios of the gas-phase and heterogeneous removal. A correlation of SO2 to the co-emitted compounds measured in the region will allow for the accurate assignment of intercepted plumes to individual power plants and urban areas. A combination of HYSPLIT trajectory modeling, use of several chemical clocks, and analysis of the wind speed along the path of the plume is used to constrain the travel time from the source to the intercepted plume.

Magnetic susceptibility as a direct measure of oxidation state in LiFePO4 batteries and cyclic water gas shift reactors.

PubMed

Kadyk, Thomas; Eikerling, Michael

2015-08-14

The possibility of correlating the magnetic susceptibility to the oxidation state of the porous active mass in a chemical or electrochemical reactor was analyzed. The magnetic permeability was calculated using a hierarchical model of the reactor. This model was applied to two practical examples: LiFePO4 batteries, in which the oxidation state corresponds with the state-of-charge, and cyclic water gas shift reactors, in which the oxidation state corresponds to the depletion of the catalyst. In LiFePO4 batteries phase separation of the lithiated and delithiated phases in the LiFePO4 particles in the positive electrode gives rise to a hysteresis effect, i.e. the magnetic permeability depends on the history of the electrode. During fast charge or discharge, non-uniform lithium distributionin the electrode decreases the hysteresis effect. However, the overall sensitivity of the magnetic response to the state-of-charge lies in the range of 0.03%, which makes practical measurement challenging. In cyclic water gas shift reactors, the sensitivity is 4 orders of magnitude higher and without phase separation, no hysteresis occurs. This shows that the method is suitable for such reactors, in which large changes of the magnetic permeability of the active material occurs.

Examining equity in access to long-lasting insecticide nets and artemisinin-based combination therapy in Anambra State, Nigeria.

PubMed

Mbachu, Chinyere O; Onwujekwe, Obinna E; Uzochukwu, Benjamin S C; Uchegbu, Eloka; Oranuba, Joseph; Ilika, Amobi L

2012-05-22

In order to achieve universal health coverage, the government of Anambra State, southeast Nigeria has distributed free Long-lasting Insecticide treated Nets (LLINs) to the general population and delivered free Artemisinin-based Combination Therapy (ACT) to pregnant women and children less than 5 years. However, the levels of coverage with LLINS and ACTs is not clear, especially coverage of different socio-economic status (SES) population groups. This study was carried out to determine the level of coverage and access to LLINs and ACTs amongst different SES groups. A questionnaire was used to collect data from randomly selected households in 19 local government areas of the State. Selected households had a pregnant woman and/or a child less than 5 years. The lot quality assurance sampling (LQAS) methodology was used in sampling. The questionnaire explored the availability and utilization of LLINs and ACTs from 2394 households. An asset-based SES index was used to examine the level of access of LLINS and ACTs to different SES quintiles. It was found that 80.5% of the households had an LLIN and 64.4% of the households stated that they actually used the nets the previous night. The findings showed that 42.3% of pregnant women who had fever within the past month received ACTs, while 37.5% of children<5 years old who had malaria in the past month had received ACTs. There was equity in ownership of nets for the range 1-5 nets per household. No significant SES difference was found in use of ACTs for treatment of malaria in children under five years old and in pregnant women. The free distribution of LLINs and ACTs increased household coverage of both malaria control interventions and bridged the equity gap in access to them among the most vulnerable groups.

Examining equity in access to long-lasting insecticide nets and artemisinin-based combination therapy in Anambra state, Nigeria

PubMed Central

2012-01-01

Background In order to achieve universal health coverage, the government of Anambra State, southeast Nigeria has distributed free Long-lasting Insecticide treated Nets (LLINs) to the general population and delivered free Artemisinin-based Combination Therapy (ACT) to pregnant women and children less than 5 years. However, the levels of coverage with LLINS and ACTs is not clear, especially coverage of different socio-economic status (SES) population groups. This study was carried out to determine the level of coverage and access to LLINs and ACTs amongst different SES groups. Methods A questionnaire was used to collect data from randomly selected households in 19 local government areas of the State. Selected households had a pregnant woman and/or a child less than 5 years. The lot quality assurance sampling (LQAS) methodology was used in sampling. The questionnaire explored the availability and utilization of LLINs and ACTs from 2394 households. An asset-based SES index was used to examine the level of access of LLINS and ACTs to different SES quintiles. Results It was found that 80.5 % of the households had an LLIN and 64.4 % of the households stated that they actually used the nets the previous night. The findings showed that 42.3 % of pregnant women who had fever within the past month received ACTs, while 37.5 % of children ≪5 years old who had malaria in the past month had received ACTs. There was equity in ownership of nets for the range 1–5 nets per household. No significant SES difference was found in use of ACTs for treatment of malaria in children under five years old and in pregnant women. Conclusions The free distribution of LLINs and ACTs increased household coverage of both malaria control interventions and bridged the equity gap in access to them among the most vulnerable groups. PMID:22545723

Solar Access: Issues and Policy Options | State, Local, and Tribal

Science.gov Websites

: approximately 2,580 megawatts (MW) of new residential solar photovoltaic (PV) capacity was brought online in home with rooftop solar Figure 1. Example of a residential solar PV system. NREL 00565 The existing Governments | NREL Solar Access: Issues and Policy Options Solar Access: Issues and Policy

Surveillance for Health Care Access and Health Services Use, Adults Aged 18–64 Years — Behavioral Risk Factor Surveillance System, United States, 2014

PubMed Central

Okoro, Catherine A.; Zhao, Guixiang; Fox, Jared B.; Eke, Paul I.; Greenlund, Kurt J.; Town, Machell

2017-01-01

Problem/Condition As a result of the 2010 Patient Protection and Affordable Care Act, millions of U.S. adults attained health insurance coverage. However, millions of adults remain uninsured or underinsured. Compared with adults without barriers to health care, adults who lack health insurance coverage, have coverage gaps, or skip or delay care because of limited personal finances might face increased risk for poor physical and mental health and premature mortality. Period Covered 2014. Description of System The Behavioral Risk Factor Surveillance System (BRFSS) is an ongoing, state-based, landline- and cellular-telephone survey of noninstitutionalized adults aged ≥18 years residing in the United States. Data are collected from states, the District of Columbia, and participating U.S. territories on health risk behaviors, chronic health conditions, health care access, and use of clinical preventive services (CPS). An optional Health Care Access module was included in the 2014 BRFSS. This report summarizes 2014 BRFSS data from all 50 states and the District of Columbia on health care access and use of selected CPS recommended by the U.S. Preventive Services Task Force or the Advisory Committee on Immunization Practices among working-aged adults (aged 18–64 years), by state, state Medicaid expansion status, expanded geographic region, and federal poverty level (FPL). This report also provides analysis of primary type of health insurance coverage at the time of interview, continuity of health insurance coverage during the preceding 12 months, and other health care access measures (i.e., unmet health care need because of cost, unmet prescription need because of cost, medical debt [medical bills being paid off over time], number of health care visits during the preceding year, and satisfaction with received health care) from 43 states that included questions from the optional BRFSS Health Care Access module. Results In 2014, health insurance coverage and other health

Accessible Information Without Disturbing Partially Known Quantum States on a von Neumann Algebra

NASA Astrophysics Data System (ADS)

Kuramochi, Yui

2018-04-01

This paper addresses the problem of how much information we can extract without disturbing a statistical experiment, which is a family of partially known normal states on a von Neumann algebra. We define the classical part of a statistical experiment as the restriction of the equivalent minimal sufficient statistical experiment to the center of the outcome space, which, in the case of density operators on a Hilbert space, corresponds to the classical probability distributions appearing in the maximal decomposition by Koashi and Imoto (Phys. Rev. A 66, 022,318 2002). We show that we can access by a Schwarz or completely positive channel at most the classical part of a statistical experiment if we do not disturb the states. We apply this result to the broadcasting problem of a statistical experiment. We also show that the classical part of the direct product of statistical experiments is the direct product of the classical parts of the statistical experiments. The proof of the latter result is based on the theorem that the direct product of minimal sufficient statistical experiments is also minimal sufficient.

Influence of oxidation state on water solubility of Si nanoparticles prepared by laser ablation in water

NASA Astrophysics Data System (ADS)

Ryabchikov, Yu. V.; Al-Kattan, A.; Chirvony, V.; Sanchez-Royo, J. F.; Sentis, M.; Timoshenko, V. Yu.; Kabashin, A. V.

2017-02-01

Femtosecond laser fragmentation from preliminarily prepared water-dispersed Si microcolloids was used to synthesize bare (ligand-free) spherical silicon nanoparticles (Si-NPs) with low size dispersion and controllable mean size from a few nm to several tens of nm. In order to control the oxidation state of Si-NPs, the fragmentation was performed in normal oxygen-saturated water (oxygen-rich conditions) or in water disoxygenated by pumping with noble gases (Ag, He) before and during the experiment (oxygen-free conditions). XPS and TEM studies revealed that Si-NPs were composed of Si nanocrystals with inclusions of silicon oxide species, covered by SiOx (1 < x < 2) shell, while the total oxide content depended whether Si-NPs were prepared in oxygen-rich or oxygen-free conditions. When placed into a dialysis box, waterdispersed Si-NPs rapidly dissolved, which was evidenced by TEM data. In this case, NPs prepared under oxygen-rich conditions demonstrated much faster dissolution kinetics and their complete disappearance after 7-10 days, while the dissolution process of less oxidized counterparts could last much longer (25-30 days). Much fast dissolution kinetics of more oxidized Si-NPs was attributed to more friable structure of nanoparticle core due to the presence of numerous oxidation-induced defects. Laser-synthesized Si-NPs are of paramount importance for biomedical applications.

Growing Oxide Nanowires and Nanowire Networks by Solid State Contact Diffusion into Solution-Processed Thin Films.

PubMed

Glynn, Colm; McNulty, David; Geaney, Hugh; O'Dwyer, Colm

2016-11-01

New techniques to directly grow metal oxide nanowire networks without the need for initial nanoparticle seed deposition or postsynthesis nanowire casting will bridge the gap between bottom-up formation and top-down processing for many electronic, photonic, energy storage, and conversion technologies. Whether etched top-down, or grown from catalyst nanoparticles bottom-up, nanowire growth relies on heterogeneous material seeds. Converting surface oxide films, ubiquitous in the microelectronics industry, to nanowires and nanowire networks by the incorporation of extra species through interdiffusion can provide an alternative deposition method. It is shown that solution-processed thin films of oxides can be converted and recrystallized into nanowires and networks of nanowires by solid-state interdiffusion of ionic species from a mechanically contacted donor substrate. NaVO 3 nanowire networks on smooth Si/SiO 2 and granular fluorine-doped tin oxide surfaces can be formed by low-temperature annealing of a Na diffusion species-containing donor glass to a solution-processed V 2 O 5 thin film, where recrystallization drives nanowire growth according to the crystal habit of the new oxide phase. This technique illustrates a new method for the direct formation of complex metal oxide nanowires on technologically relevant substrates, from smooth semiconductors, to transparent conducting materials and interdigitated device structures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanistic Investigations of Water Oxidation by a Molecular Cobalt Oxide Analogue: Evidence for a Highly Oxidized Intermediate and Exclusive Terminal Oxo Participation.

PubMed

Nguyen, Andy I; Ziegler, Micah S; Oña-Burgos, Pascual; Sturzbecher-Hohne, Manuel; Kim, Wooyul; Bellone, Donatela E; Tilley, T Don

2015-10-14

Artificial photosynthesis (AP) promises to replace society's dependence on fossil energy resources via conversion of sunlight into sustainable, carbon-neutral fuels. However, large-scale AP implementation remains impeded by a dearth of cheap, efficient catalysts for the oxygen evolution reaction (OER). Cobalt oxide materials can catalyze the OER and are potentially scalable due to the abundance of cobalt in the Earth's crust; unfortunately, the activity of these materials is insufficient for practical AP implementation. Attempts to improve cobalt oxide's activity have been stymied by limited mechanistic understanding that stems from the inherent difficulty of characterizing structure and reactivity at surfaces of heterogeneous materials. While previous studies on cobalt oxide revealed the intermediacy of the unusual Co(IV) oxidation state, much remains unknown, including whether bridging or terminal oxo ligands form O2 and what the relevant oxidation states are. We have addressed these issues by employing a homogeneous model for cobalt oxide, the [Co(III)4] cubane (Co4O4(OAc)4py4, py = pyridine, OAc = acetate), that can be oxidized to the [Co(IV)Co(III)3] state. Upon addition of 1 equiv of sodium hydroxide, the [Co(III)4] cubane is regenerated with stoichiometric formation of O2. Oxygen isotopic labeling experiments demonstrate that the cubane core remains intact during this stoichiometric OER, implying that terminal oxo ligands are responsible for forming O2. The OER is also examined with stopped-flow UV-visible spectroscopy, and its kinetic behavior is modeled, to surprisingly reveal that O2 formation requires disproportionation of the [Co(IV)Co(III)3] state to generate an even higher oxidation state, formally [Co(V)Co(III)3] or [Co(IV)2Co(III)2]. The mechanistic understanding provided by these results should accelerate the development of OER catalysts leading to increasingly efficient AP systems.

Accessing Ultrahigh-Pressure, Quasi-Isentropic States of Matter

NASA Astrophysics Data System (ADS)

Lorenz, Thomas

2004-11-01

A new approach to materials science at extreme pressures has been developed on the OMEGA laser, using a ramped plasma piston drive. The laser drives a shock through a solid plastic reservoir that unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, diagnosed with VISAR measurements, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation. [1] This has been demonstrated at OMEGA at pressures of P = 0.1-2.0 Mbar in Al foils. [2] In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor (RT) unstable interfaces. The material strength is predicted to be as much as an order of magnitude higher at P ˜ 1 Mbar than at ambient pressures. Initial RT measurements testing this prediction in foils of Al and V will be shown. We also use TEM microscopy of recovered targets to show that the samples never melted, and the presence of pressure-induced structural defects. [3,4] Experimental designs based on this drive have been developed for the NIF laser, predicting that solid-state samples can be quasi-isentropically driven to pressures an order of magnitude higher than on Omega - accessing new regimes of dense, high-pressure matter. [5] [1] J. Edwards et al., Phys. Rev. Lett., 92, 075002 (2004). [2] K.T. Lorenz et al., submitted, J. Appl. Phys. (2004). [3] J. McNaney et al., in press, Met. Mat. Trans. 35A (2004). [4] E.M. Bringa et al., to be submitted, Nature (2004). [5] B.A. Remington et al., in press, Met. Mat. Trans. 35A (2004). This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore

Preserving Charge and Oxidation State of Au(III) Ions in an Agent-Functionalized Nanocrystal Model System

PubMed Central

2011-01-01

Supporting functional molecules on crystal facets is an established technique in nanotechnology. To preserve the original activity of ionic metallorganic agents on a supporting template, conservation of the charge and oxidation state of the active center is indispensable. We present a model system of a metallorganic agent that, indeed, fulfills this design criterion on a technologically relevant metal support with potential impact on Au(III)-porphyrin-functionalized nanoparticles for an improved anticancer-drug delivery. Employing scanning tunneling microscopy and -spectroscopy in combination with photoemission spectroscopy, we clarify at the single-molecule level the underlying mechanisms of this exceptional adsorption mode. It is based on the balance between a high-energy oxidation state and an electrostatic screening-response of the surface (image charge). Modeling with first principles methods reveals submolecular details of the metal–ligand bonding interaction and completes the study by providing an illustrative electrostatic model relevant for ionic metalorganic agent molecules, in general. PMID:21736315

The Judicialization of Health and the Quest for State Accountability: Evidence from 1,262 Lawsuits for Access to Medicines in Southern Brazil

PubMed Central

Socal, Mariana P.; Amon, Joseph J.

2016-01-01

Abstract The impact of increasing numbers of lawsuits for access to medicines in Brazil is hotly debated. Government officials and scholars assert that the “judicialization of health” is driven by urban elites and private interests, and is used primarily to access high-cost drugs. Using a systematic sample of 1,262 lawsuits for access to medicines filed against the southern Brazilian state of Rio Grande do Sul, we assess these claims, offering empirical evidence that counters prevailing myths and affirms the heterogeneity of the judicialization phenomenon. Our findings show that the majority of patient-litigants are in fact poor and older individuals who do not live in major metropolitan areas and who depend on the state to provide their legal representation, and that the majority of medicines requested were already on governmental formularies. Our data challenge arguments that judicialization expands inequities and weakens the universal health care system. Our data also suggest that judicialization may serve as a grassroots instrument for the poor to hold the state accountable. Failing to acknowledge regional differences and attempting to fit all data into one singular narrative may be contributing to a biased interpretation of the nature of judicialization, and limiting the understanding of its drivers, consequences, and implications at local levels. PMID:27781011

V6O13 films by control of the oxidation state from aqueous precursor to crystalline phase.

PubMed

Peys, Nick; Ling, Yun; Dewulf, Daan; Gielis, Sven; De Dobbelaere, Christopher; Cuypers, Daniel; Adriaensens, Peter; Van Doorslaer, Sabine; De Gendt, Stefan; Hardy, An; Van Bael, Marlies K

2013-01-28

An aqueous deposition process for V(6)O(13) films is developed whereby the vanadium oxidation state is continuously controlled throughout the entire process. In the precursor stage, a controlled wet chemical reduction of the vanadium(V) source with oxalic acid is achieved and monitored by (51)Vanadium Nuclear Magnetic Resonance ((51)V-NMR) and Ultraviolet-Visible (UV-Vis) spectroscopy. The resulting vanadium(IV) species in the aqueous solution are identified as mononuclear citrato-oxovanadate(IV) complexes by Electron Paramagnetic Resonance (EPR) and Fourier Transform Infra-Red (FTIR) spectroscopy. This precursor is successfully employed for the deposition of uniform, thin films. The optimal deposition and annealing conditions for the formation of crystalline V(6)O(13), including the control of the vanadium oxidation state, are determined through an elaborate study of processing temperature and O(2) partial pressure. To ensure a sub 100 nm adjustable film thickness, a non-oxidative intermediate thermal treatment is carried out at the end of each deposition cycle, allowing maximal precursor decomposition while still avoiding V(IV) oxidation. The resulting surface hydrophilicity, indispensable for the homogeneous deposition of the next layer, is explained by an increased surface roughness and the increased availability of surface vanadyl groups. Crystalline V(6)O(13) with a preferential (002) orientation is obtained after a post deposition annealing in a 0.1% O(2) ambient for thin films with a thickness of 20 nm.

Understanding Digital Technology Access and Use Among New York State Residents to Enhance Dissemination of Health Information.

PubMed

Manganello, Jennifer A; Gerstner, Gena; Pergolino, Kristen; Graham, Yvonne; Strogatz, David

2016-01-01

Many state and local health departments, as well as community organizations, have been using new technologies to disseminate health information to targeted populations. Yet little data exist that show access and use patterns, as well as preferences for receiving health information, at the state level. This study was designed to obtain information about media and technology use, and health information seeking patterns, from a sample of New York State (NYS) residents. A cross-sectional telephone survey (with mobile phones and landlines) was developed to assess media and technology access, use patterns, and preferences for receiving health information among a sample of 1350 residents in NYS. The survey used random digit dialing methodology. A weighted analysis was conducted utilizing Stata/SE software. Data suggest that NYS residents have a high level of computer and Internet use; 82% have at least one working computer at home, and 85% use the Internet at least sometimes. Mobile phone use is also high; 90% indicated having a mobile phone, and of those 63% have a smartphone. When asked about preferences for receiving health information from an organization, many people preferred websites (49%); preferences for other sources varied by demographic characteristics. Findings suggest that the Internet and other technologies are viable ways to reach NYS residents, but agencies and organizations should still consider using traditional methods of communication in some cases, and determine appropriate channels based on the population of interest.

Understanding Digital Technology Access and Use Among New York State Residents to Enhance Dissemination of Health Information

PubMed Central

Gerstner, Gena; Pergolino, Kristen; Graham, Yvonne; Strogatz, David

2016-01-01

Background Many state and local health departments, as well as community organizations, have been using new technologies to disseminate health information to targeted populations. Yet little data exist that show access and use patterns, as well as preferences for receiving health information, at the state level. Objective This study was designed to obtain information about media and technology use, and health information seeking patterns, from a sample of New York State (NYS) residents. Methods A cross-sectional telephone survey (with mobile phones and landlines) was developed to assess media and technology access, use patterns, and preferences for receiving health information among a sample of 1350 residents in NYS. The survey used random digit dialing methodology. A weighted analysis was conducted utilizing Stata/SE software. Results Data suggest that NYS residents have a high level of computer and Internet use; 82% have at least one working computer at home, and 85% use the Internet at least sometimes. Mobile phone use is also high; 90% indicated having a mobile phone, and of those 63% have a smartphone. When asked about preferences for receiving health information from an organization, many people preferred websites (49%); preferences for other sources varied by demographic characteristics. Conclusions Findings suggest that the Internet and other technologies are viable ways to reach NYS residents, but agencies and organizations should still consider using traditional methods of communication in some cases, and determine appropriate channels based on the population of interest. PMID:27227163

45 CFR 283.9 - What do eligible States need to know to access and use the bonus funds?

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 2 2014-10-01 2012-10-01 true What do eligible States need to know to access and use the bonus funds? 283.9 Section 283.9 Public Welfare Regulations Relating to Public Welfare OFFICE... HEALTH AND HUMAN SERVICES IMPLEMENTATION OF SECTION 403(A)(2) OF THE SOCIAL SECURITY ACT BONUS TO REWARD...

45 CFR 283.9 - What do eligible States need to know to access and use the bonus funds?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 2 2011-10-01 2011-10-01 false What do eligible States need to know to access and use the bonus funds? 283.9 Section 283.9 Public Welfare Regulations Relating to Public Welfare OFFICE... HEALTH AND HUMAN SERVICES IMPLEMENTATION OF SECTION 403(A)(2) OF THE SOCIAL SECURITY ACT BONUS TO REWARD...

45 CFR 283.9 - What do eligible States need to know to access and use the bonus funds?

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 2 2013-10-01 2012-10-01 true What do eligible States need to know to access and use the bonus funds? 283.9 Section 283.9 Public Welfare Regulations Relating to Public Welfare OFFICE... HEALTH AND HUMAN SERVICES IMPLEMENTATION OF SECTION 403(A)(2) OF THE SOCIAL SECURITY ACT BONUS TO REWARD...

45 CFR 283.9 - What do eligible States need to know to access and use the bonus funds?

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 2 2012-10-01 2012-10-01 false What do eligible States need to know to access and use the bonus funds? 283.9 Section 283.9 Public Welfare Regulations Relating to Public Welfare OFFICE... HEALTH AND HUMAN SERVICES IMPLEMENTATION OF SECTION 403(A)(2) OF THE SOCIAL SECURITY ACT BONUS TO REWARD...

45 CFR 283.9 - What do eligible States need to know to access and use the bonus funds?

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 2 2010-10-01 2010-10-01 false What do eligible States need to know to access and use the bonus funds? 283.9 Section 283.9 Public Welfare Regulations Relating to Public Welfare OFFICE... HEALTH AND HUMAN SERVICES IMPLEMENTATION OF SECTION 403(A)(2) OF THE SOCIAL SECURITY ACT BONUS TO REWARD...

Public access to New Hampshire state waters: a comparison of three cohorts of residents across three distinct geographic

Treesearch

Kim Pawlawski; Robert A. Robertson; Laura Pfister

2003-01-01

This study was intended to provide New Hampshire agencies with a better understanding of public access-related demand information. Through an analysis of three groups of New Hampshire residents based upon geographic location and length of residency, important issues and attitudes were identified from all over the State. The results of this study will assist in policy-...

20 CFR 625.18 - Public access to Agreements.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Public access to Agreements. 625.18 Section 625.18 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR DISASTER UNEMPLOYMENT ASSISTANCE § 625.18 Public access to Agreements. The State agency of a State will make available...

The Every Student Succeeds Act, State Efforts to Improve Access to Effective Educators, and the Importance of School Leadership

ERIC Educational Resources Information Center

Fuller, Edward J.; Hollingworth, Liz; Pendola, Andrew

2017-01-01

Purpose: Our primary purpose is to examine the degree to which state equity plans identify the distribution of principals and principal turnover as factors influencing three leadership mechanisms that affect student access to effective teachers--namely, hiring of teachers, building instructional capacity of teachers, and managing teacher turnover.…

Nanomorphology Effects in Semiconductors with Native Ferromagnetism: Hierarchical Europium (II) Oxide Tubes Prepared via a Topotactic Nanostructure Transition.

PubMed