Materials Data on HoGa2Ni (SG:63) by Materials Project

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

Kristin Persson

2017-05-05

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Transport properties of RCo_2B_2C with R = Dy, Ho, and Pr single

NASA Astrophysics Data System (ADS)

Duran, Alejandro; Escudero, Roberto

2002-03-01

Single crystals of (Dy, Ho, Pr)Co_2B_2C have been grown by a cold copper crucible method. Metallurgical and structural studies indicate that this borocarbide family melts incongruently and crystallizes as a derivative structure of the ThCr_2Si_2. The family accepts rare earth atoms depending on the type of transition metals used to form the compound. For instance with Ni atoms, all lanthanides ranging from the large lanthanum to lutetium ions are reported to form RNi_2B_2C single crystals, so far no single crystals have been obtained when changing Ni by Cobalt. A comparison of the structural parameters of the RCo_2B_2C with the RNiHo, Pr) compounds indicate that the atomic distance between transition metal atoms contracts with the insertion of the Co ion, resulting in an increasing of the c parameter and decreasing volume. Several recent reports published in the current literature related on the physical properties of RCo_2B_2C (R = rare earth metals and Y) have been only performed on polycrystalline samples, they commonly contain small amounts of second phases. High quality single crystals are necessaries in order to better understand the physical properties, such as anisotropy in the transport and in the magnetic properties. In this report we show magnetic susceptibility and resistivity measurements performed in single crystals in the ab-plane and c direction for 2 - 320 K temperature range for the three single crystals of (Dy, Ho, Pr)Co_2B_2C.

N-HO and N-HCl supported 1D chains of heterobimetallic CuII/NiII-SnIV cocrystals.

PubMed

Hazra, Susanta; Meyrelles, Ricardo; Charmier, Adilia Januário; Rijo, Patrícia; Guedes da Silva, M Fátima C; Pombeiro, Armando J L

2016-11-28

The Schiff base H 2 L 1 [N,N'-ethylenebis(3-methoxysalicylaldimine)] or H 2 L 2 [N,N'-ethylenebis(3-ethoxysalicylaldimine)] was reacted with MCl 2 ·xH 2 O and SnCl 4 ·5H 2 O to afford the supramolecular heterobimetallic systems (H 2 ED) 2+ ·2[ML]·[SnCl 6 ] 2- [M = Cu, L = L 1 (1), L = L 2 (2); M = Ni, L = L 1 (3), L = L 2 (4); ED = 1,2-ethylenediamine], whose structures were established by single crystal X-ray analyses. Each structure includes different entities, viz. a mononuclear [CuL]/[NiL] neutral complex (coformer), a hexachlorostannate dianion [SnCl 6 ] 2- , a 1,2-ethylenediammonium dication (H 2 ED 2+ ) and, only in 2 and 4, a methanol molecule. Based on the work of Grothe et al. (Cryst. Growth Des., 2016, 16, 3237-3243), compounds 1 and 3 are cocrystal salts, 2 and 4 are cocrystal salt solvates. The ionic pairs (H 2 ED) 2+ ·[SnCl 6 ] 2- in 1-4 are encapsulated by the Cu- or Ni-complexes, and stabilized by N-HO and one N-HCl bond interactions leading to infinite 1D chains. The antimicrobial studies of 1-4 against yeasts (C. albicans and S. cerevisiae) and Gram-positive (S. aureus and E. faecalis) and -negative bacteria (P. aeruginosa and E. coli) indicate that the Ni 2 Sn systems (3 and 4) are more active than the analogous Cu 2 Sn ones (1 and 2).

HO(x) Measurements in PEM Tropics B with the Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS)

NASA Technical Reports Server (NTRS)

Brune, William H.

2001-01-01

The primary objective of PEM Tropics B was to study the processes responsible for the production and loss of tropospheric ozone over the tropical Pacific. This region of the globe contains very clean air as well as aged, polluted air that was advected from both the Asian and American continents. Understanding ozone requires understanding of HO(x) (HO(x) = OH + HO2) chemistry, since the reaction between H02 and NO leads to ozone production and the production of OH often requires ozone loss. In addition, OH is the atmosphere's primary oxidant. Since most atmospheric oxidation is thought to occur in the tropical lower troposphere, measurements during PEM Tropics B should provide an important test of the OH abundances and distributions. Thus, understanding and thoroughly testing HO(x) processes was an important objective of PEM Tropics B. Several issues need to be tested, One is HO, production rates and sources, since HO,, production directly affects ozone production and loss. Another is HO(x) behavior in and around clouds, since HO(x) is lost to cloud particles, but convection may bring HO(x) precursors from near the surface to the upper troposphere. A third is the rise and fall of HO(x) at sunrise and sunset, since these variations give strong indications of the important sources and sinks of HO(x). Making and interpreting high-quality OH and H02 measurements from the NASA DC-8 during PEM Tropics B is the objective of this research effort.

Rare-Earth Oxide Ion (Tm3+, Ho3+, and U3+) Doped Glasses and Fibres for 1.8 to 4 Micrometer Coherent and Broadband Sources

DTIC Science & Technology

2006-07-24

oxide ( TeO2 ) , fluorine- containing silicate (SiOF2) and germanate (GeOF2) glass hosts for each dopant by characterising the spectroscopic properties...Earth Oxide Ion (Tm3+, Ho3+, And U3+) Doped Glasses And Fibres For 1.8 To 4 Micrometer Coherent And Broadband Sources 5c. PROGRAM ELEMENT NUMBER 5d...Rare-earth oxide ion (Tm3+, Ho3+, and U3+) doped glasses and fibres for 1.8 to 4 micrometer coherent and broadband sources Report prepared

Trace metals partitioning between particulate and dissolved phases along a tropical mangrove estuary (Can Gio, Vietnam).

PubMed

Thanh-Nho, Nguyen; Strady, Emilie; Nhu-Trang, Tran-Thi; David, Frank; Marchand, Cyril

2018-04-01

Mangroves can be considered as biogeochemical reactors along (sub)tropical coastlines, acting both as sinks or sources for trace metals depending on environmental factors. In this study, we characterized the role of a mangrove estuary, developing downstream a densely populated megacity (Ho Chi Minh City, Vietnam), on the fate and partitioning of trace metals. Surface water and suspended particulate matter were collected at four sites along the estuarine salinity gradient during 24 h cycling in dry and rainy seasons. Salinity, pH, DO, TSS, POC, DOC, dissolved and particulate Fe, Mn, Cr, As, Cu, Ni, Co and Pb were measured. TSS was the main trace metals carrier during their transit in the estuary. However, TSS variations did not explain the whole variability of metals distribution. Mn, Cr and As were highly reactive metals while the other metals (Fe, Ni, Cu, Co and Pb) presented stable log K D values along the estuary. Organic matter dynamic appeared to play a key role in metals fractioning. Its decomposition during water transit in the estuary induced metal desorption, especially for Cr and As. Conversely, dissolved Mn concentrations decreased along the estuary, which was suggested to result from Mn oxidative precipitation onto solid phase due to oxidation and pH changes. Extra sources as pore-water release, runoff from adjacent soils, or aquaculture effluents were suggested to be involved in trace metal dynamic in this estuary. In addition, the monsoon increased metal loads, notably dissolved and particulate Fe, Cr, Ni and Pb. Copyright © 2018 Elsevier Ltd. All rights reserved.

Formation of todorokite from vernadite in Ni-rich hemipelagic sediments

NASA Astrophysics Data System (ADS)

Bodeï, Sabine; Manceau, Alain; Geoffroy, Nicolas; Baronnet, Alain; Buatier, Martine

2007-12-01

Todorokite is considered to form from vernadite in nature and commonly concentrates nickel. However, this mineralogical transformation has never been imaged nor explained mechanistically, and its effect on the uptake of nickel has never been quantified at the molecular-level. We have characterized these reactions at the macroscopic, microscopic, nanoscopic and atomic scales in a marine manganese concretion by combining transmission electron microscopy, electron and X-ray microprobe analysis, powder and micro X-ray diffraction, and Mn and Ni K-edge EXAFS spectroscopy. The concretion was collected during the Ticoflux II expedition near the Nicoya Peninsula, Costa Rica, and is representative of Mn deposits in hemipelagic sediments. It consists of 5 to 25 μm aggregates, shaped like sea-urchins, with a core of 7Å-vernadite (1.0 wt% Ni), a rim of 10Å-vernadite (3.8 wt% Ni), and an outermost region of todorokite fibers (1.9 wt% Ni) that extend outwards. The crystallites of 7Å-vernadite are single- to bi-layered, with hexagonal layer symmetry ( a = b = 2.83 Å), and an average structural formula of Mg0.1612+Ca0.0102+K0.016+[Mn0.9024+VacNi0.0152+]O·nHO. The crystallites of 10Å-vernadite contain 10 to 20 layers semi-coherently stacked in the ab plane and uniformly separated in the [0 0 1] direction by ˜9 Å due to the intercalation of hydrated Mg 2+ cations. The average structural formula of 10Å-vernadite is Mg0.1872+Ca0.0162+K0.013+[Mn0.8644+VacNi0.0622+]O·nHO if the layers contain vacancy sites, or alternately Mg0.2022+Ca0.0182+K0.014+[Mn0.6134+Mn0.3203+Ni0.0672+]O·nHO, if they contain Mn 3+. The average formula of todorokite is Mg0.1782+Ca0.0132+K0.019+[Mn0.6124+Mn0.3563+Ni0.0322+]O·nHO. A genetic model is proposed based on combining these new data with previously published results. The thermodynamically unstable 7Å-vernadite transforms via dissolution-recrystallization to semi-ordered Mg-rich 10Å-vernadite. Nickel is released from dissolved biogenic silica or reduced organic matter, and taken up mainly in the Mn layer of 10Å-vernadite. Interlayer magnesium serves as a template to the further topotactic transformation of 10Å-vernadite to todorokite. The dimension of the todorokite tunnels in the [0 0 1] direction is uniform and determined by the size of the hydrated Mg 2+ ion (8.6 Å). The tunnel dimension in the [1 0 0] direction depends on the density of Mg 2+ in the interlayer and the superstructure of the phyllomanganate layer. If the parent phyllomanganate contains high amounts of Mg 2+ (i.e., high layer charge), or Mn 3+ and Mn 4+ cations ordered following the Mn 3+-Mn 4+-Mn 4+ sequence as in synthetic triclinic birnessite, then the tunnel dimension is ideally 3 × 3 octahedral chain widths in both crystallographic directions. Otherwise, the tunnel dimension is incoherent in the [1 0 0] direction (i.e., T(3, n) tunnel structure), as has been observed in all natural todorokites. Natural todorokite is defective because the precursor natural phyllomanganates either have a layer charge deficit below 0.33e per octahedral site, or rarely are triclinic birnessite. The abundance of Mg in seawater and its key role in converting phyllomanganate to tectomanganate with T(3, n) tunnel structure explain why todorokite is common in marine ferromanganese oxides, and seldom present in terrestrial environments. The topotactic phase transformation described here is the only known route to todorokite crystallization. This implies that all natural todorokites may be authigenic because they are formed in situ from a phyllomanganate precursor.

Efficient upconversion emission in Ho3+/Nd3+ co-doped oxyfluorosilicate glasses

NASA Astrophysics Data System (ADS)

Devarajulu, G.; Raju, B. Deva Prasad

2018-04-01

We report on an efficient Ho3+ and Ho3+/Nd3+ co-doped oxyfluorosilicate glasses upon excitation with an 808 nm laser diode. The detailed fluorescence have been studied under this excitation source and energy transfer mechanisms in Ho3+/Nd3+ co-doped oxyfluorosilicate glasses. The upconversion peaks at 486, 547 and 596 nm were observed in Nd3+/Ho3+ co-doped sample. The intensity of upconversion emission transitions in Ho3+ depends on the neodymium codopent concentration. These results indicate that Nd3+ ions can be potentially used as sensitizer for Ho3+ ions to stimulate the intense upconversion emission. The energy transfer mechanism between Nd3+ and Ho3+ was analyzed pursuant to the absorption spectra, upconversion spectra and the energy level structures of Nd3+ and Ho3+ ions have been briefly discussed.

SOURCE APPORTIONMENT OF FINE PARTICULATE MATTER IN THE U.S. AND ASSOCIATIONS WITH LUNG INFLAMMATORY MARKERS IL -8, COX -2 AND HO -1

EPA Science Inventory

Associations are well established between particulate matter (PM) and increased human mortality and morbidity. The association between fine PM sources and lung inflammatory markers IL-8, COX-2, and HO-1 was evaluated in this study.

Octanuclear Heterobimetallic {Ni4Ln4} Assemblies Possessing Ln4 Square Grid [2 × 2] Motifs: Synthesis, Structure, and Magnetism.

PubMed

Biswas, Sourav; Goura, Joydeb; Das, Sourav; Topping, Craig V; Brambleby, Jamie; Goddard, Paul A; Chandrasekhar, Vadapalli

2016-09-06

Octanuclear heterobimetallic complexes, [Ln4Ni4(H3L)4(μ3-OH)4(μ2-OH)4]4Cl·xH2O·yCHCl3 (Dy(3+), x = 30.6, y = 2 (1); Tb(3+), x = 28, y = 0 (2) ; Gd(3+), x = 25.3, y = 0 (3); Ho(3+), x = 30.6, y = 3 (4)) (H5L = N1,N3-bis(6-formyl-2-(hydroxymethyl)-4-methylphenol)diethylenetriamine) are reported. These are assembled by the cumulative coordination action of four doubly deprotonated compartmental ligands, [H3L](2-), along with eight exogenous -OH ligands. Within the core of these complexes, four Ln(3+)'s are distributed to the four corners of a perfect square grid while four Ni(2+)'s are projected away from the plane of the Ln4 unit. Each of the four Ni(2+)'s possesses distorted octahedral geometry while all of the Ln(3+)'s are crystallographically equivalent and are present in an elongated square antiprism geometry. The magnetic properties of compound 3 are dominated by an easy-plane single-ion anisotropy of the Ni(2+) ions [DNi = 6.7(7) K] and dipolar interactions between Gd(3+) centers. Detailed ac magnetometry reveals the presence of distinct temperature-dependent out-of-phase signals for compounds 1 and 2, indicative of slow magnetic relaxation. Magnetochemical analysis of complex 1 implies the 3d and the 4f metal ions are engaged in ferromagnetic interactions with SMM behavior, while dc magnetometry of compound 2 is suggestive of an antiferromagnetic Ni-Tb spin-exchange with slow magnetic relaxation due to a field-induced level crossing. Compound 4 exhibits an easy-plane single-ion anisotropy for the Ho(3+) ions and weak interactions between spin centers.

Signature of magnetoelectric coupling of xNiFe2O4 - (1-x)HoMnO3 (x = 0.1 and 0.3) multiferroic nanocomposites

NASA Astrophysics Data System (ADS)

Mandal, S. K.; Debnath, Rajesh; Singh, Swati; Nath, A.; Dey, P.; Nath, T. K.

2017-12-01

The magnetoelectric coupling of xNiFe2O4-(1-x)HoMnO3 (x = 0.1 and 0.3) multiferroics nanocomposites prepared through low temperature chemical pyrophoric reaction process has been investigated at room temperature. The signature of magnetoelectric coefficient of these nanocomposites is mainly due to the magnetostriction and magnetodielectric properties of the materials. These nanocomposites show the ferroelectric behaviour at room temperature. AC electrical properties of nanocomposites have been studied with applied magnetic fields and temperatures. Nyquist plots at different magnetic fields and temperatures have been fitted using parallel combinations of resistance-capacitor circuits. Moreover, we have estimated activation energy of those composites using Arrhenius relation, which indicates that same kinds of charge carrier are responsible for relaxation process in grain boundaries and grain of the sample. Furthermore, from the analysis of ac conductivity data as a function of frequency is attributed to the large polaronic hopping in the conduction process in the system.

Neutron powder diffraction refinement of the nuclear and magnetic structures of HoNi{sub 2}B{sub 2}C at R.T., 10, 5.1, and 2.2 K

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

Huang, Q.; Grigereit, T.E.; Lynn, J.W.

The nuclear and magnetic structures of HoNi{sub 2}B{sub 2}C have been investigated by neutron powder diffraction at room temperature and at 10, 5.1 and 2.2K. The compound crystallizes with the symmetry of space group 14/mmm and has room temperature lattice parameters a = 3.5170(1) and c = 10.5217(3) {angstrom}. No phase transitions of the nuclear structure have been observed in the range of temperatures examined. Magnetic peaks begin to appear at about 8K. The magnetic structure is the superposition of two configurations, one in which ferromagnetic sheets of holmium spins parallel to the a-b plane are coupled antiferromagnetically along themore » c-axis, and another in which the ferromagnetic planes are rotated away from the antiparallel configuration to give an incommensurate helicoidal structure with a period approximately equal to twelve times the length of the c-axis. The helicoidal structure competes with superconductivity while the antiferromagnetism coexists with it.« less

HOx Observation and Model Comparison During INTEX-A 2004

NASA Technical Reports Server (NTRS)

Ren, Xinrong; Olson, Jennifer R.; Crawford, James H.; Brune, William H.; Mao, Jingqiu; Long, Robert B.; Chen, Zhong; Chen, Gao; Avery, Melody A.; Sachse, Glen W.;

A Reevaluation of Airborne HO(x) Observations from NASA Field Campaigns

NASA Technical Reports Server (NTRS)

Olson, Jennifer; Crawford, James H.; Chen, Gao; Brune, William H.; Faloona, Ian C.; Tan, David; Harder, Hartwig; Martinez, Monica

2006-01-01

In-situ observations of tropospheric HO(x) (OH and HO2) obtained during four NASA airborne campaigns (SUCCESS, SONEX, PEM-Tropics B and TRACE-P) are reevaluated using the NASA Langley time-dependent photochemical box model. Special attention is given to previously diagnosed discrepancies between observed and predicted HO2 which increase with higher NO(x) levels and at high solar zenith angles. This analysis shows that much of the model discrepancy at high NO(x) during SUCCESS can be attributed to modeling observations at time-scales too long to capture the nonlinearity of HO(x) chemistry under highly variable conditions for NO(x). Discrepancies at high NO(x) during SONEX can be moderated to a large extent by complete use of all available precursor observations. Differences in kinetic rate coefficients and photolysis frequencies available for previous studies versus current recommendations also explain some of the disparity. Each of these causes is shown to exert greater influence with increasing NO(x) due to both the chemical nonlinearity between HO(x) and NO(x) and the increased sensitivity of HO(x) to changes in sources at high NO(x). In contrast, discrepancies at high solar zenith angles will persist until an adequate nighttime source of HO(x) can be identified. It is important to note that this analysis falls short of fully eliminating the issue of discrepancies between observed and predicted HO(x) for high NO(x) environments. These discrepancies are not resolved with the above causes in other data sets from ground-based field studies. Nevertheless, these results highlight important considerations in the application of box models to observationally based predictions of HO(x) radicals.

Studies of magnetostriction and spin polarized band structures of rare earth intermetallics

NASA Technical Reports Server (NTRS)

Wallace, W. E.

1979-01-01

Anisotropic magnetostriction measurements of R6Fe23, R = (Tb, Dy, Ho, and Er) were carried out from 77 K to room temperature. Magnetic fields up to 2.1 Tesla were applied. All the compounds exhibited large magnetostrictions at 77 K, the largest effect being obtained for Tb6Fe23. Saturation magnetostriction values for the compounds were also determined for 77 K and room temperature. Results of the temperature dependence of magnetostriction for Er6Fe23 are in good agreement with Callen and Callen's single ion theory. Therefore, the main sources of magnetostriction in this compound is the Er ion. The spin-up and spin-down electronic energy bands, the density of states and the magnetic moments of YCo5, SmCo5, and GdCo5 were calculated by the spin polarized augmented plane wave technique. The calculations obtained show the origin of the moment, provide good estimates of its magnitude and variation, and the reasons for those variations. They also show the important role of partial charge transfer and of d-d electronic coupling. Calculations for LaNi5 and GdNi5 systems are discussed.

New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub 6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd–Yb)

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

Pani, M.; Manfrinetti, P.; Provino, A.

2014-02-15

Novel RNi{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi{sub 6}Si{sub 6}-type structure for R=Y, Sm, Gd–Yb (tP52, space group P4{sup ¯}b2N 117) that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 5 K. However, the inverse paramagnetic susceptibility of LaNi{sub 6}Si{sub 6} does not follow Curie–Weiss law. The DyNi{sub 6}Si{sub 6}more » shows ferromagnetic-like saturation behaviour at 5 K in applied fields of 50 kOe, giving rise to a magnetic moment value of 6.5 μ{sub B}/f.u. in 50 kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. - Graphical abstract: Novel (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure and (Y, Sm, Gd–Yb) adopt the new YNi{sub 6}Si{sub 6}-type structure that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 4.2 K. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. Display Omitted - Highlights: • The new (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure. • The new (Y, Sm, Gd–Yb)Ni{sub 6}Si{sub 6} compounds adopt the new YNi{sub 6}Si{sub 6}-type structure. • TbNi{sub 6}Si{sub 6} has square modulated c-collinear antiferromagnetic ordering below ∼10 K.« less

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

Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru; Isnard, O.; Université Grenoble Alpes, Inst. Néel, F-38042 Grenoble

The crystal structure of new Mo{sub 2}NiB{sub 2}-type (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} (Immm, No. 71, oI10) and La{sub 2}Ni{sub 3}-type (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} (Cmce No. 64, oC20) compounds has been established using powder X-ray diffraction studies. Magnetization measurements show that the Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} undergoes a ferromagnetic transition at ~66 K, whereas isostructural Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} shows an antiferromagnetic transition at ~52 K and a field-induced metamagnetic transition at low temperatures. Neutron diffraction study shows that, in zero applied field, Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} exhibits c-axis antiferromagnetic order with propagation vectormore » K=[1/2, 0, 1/2] below its magnetic ordering temperature and Tb magnetic moment reaches a value of 8.32(5) μ{sub B} at 2 K. The La{sub 2}Ni{sub 3}-type Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} exhibits ferromagnetic like transition at ~42 K with coexisting antiferromagnetic interactions and field induced metamagnetic transition below ~17 K. The magnetocaloric effect of Gd{sub 2}Ni{sub 2.35}Si{sub 0.65}, Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} is calculated in terms of isothermal magnetic entropy change and it reaches a maximum value of −14.3 J/kg K, −5.3 J/kg K and −10.3 J/kg K for a field change of 50 kOe near 66 K, 52 K and 42 K, respectively. Low temperature magnetic ordering with enhanced anisotropic effects in Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.35}Si{sub 0.65} is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +12.8 J/kg K and ~+9.9 J/kg K, respectively at 7 K for a field change of 50 kOe. - Graphical abstract: The (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} supplement the series of Mo{sub 2}NiB{sub 2}-type rare earth compounds, whereas the (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} supplement the series of La{sub 2}Ni{sub 3}-type rare earth compounds. The variation of alloy’s composition by ~3 at% i.e. from Dy{sub 2}Ni{sub 2.35}Si{sub 0.65} to Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} leads to significant transformation of crystal structure of compound with different variant of distortion of Po-type rare earth sublattice, as in Gd–Co–Ga and Er–Ni–In systems: the Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Co{sub 2}Ga and La{sub 2}Ni{sub 3}-type Gd{sub 2}Co{sub 2.9}Ga{sub 0.1}, and Mo{sub 2}FeB{sub 2}-type Er{sub 2}Ni{sub 1.78}In and Mn{sub 2}AlB{sub 2}-type Er{sub 2}Ni{sub 2}In. Magnetization measurements indicate collinear ferromagnetic ordering of Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} and a complex antiferromagnetic ordering with low-temperature metamagnetic nature for Mo{sub 2}NiB{sub 2}-type Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} compounds. However, neutron diffraction study in zero applied field of Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} reveals c-axis pure antiferromagnetic ordering of terbium sublattice with K=[1/2, 0, 1/2] propagation vector. Magnetization measurements indicate ferromagnetic order with coexisting antiferromagnetic interactions and low-temperature metamagnetic state for La{sub 2}Ni{sub 3}-type Dy{sub 2}Ni{sub 2.5}Si{sub 0.5}. We suggest possible polymorphism in other Mo{sub 2}FeB{sub 2}-type, Mo{sub 2}NiB{sub 2}-type, La{sub 2}Ni{sub 3}-type and Mn{sub 2}AlB{sub 2}-type rare earth compounds with corresponding change in their magnetic properties. - Highlights: • (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} compounds crystallize in the Mo{sub 2}NiB{sub 2}-type structure. • (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} compounds crystallize in the La{sub 2}Ni{sub 3}-type structure. • Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} shows pure ferromagnetic type ordering. • Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} show mixed ferro-antiferromagnetic ordering. • Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} exhibit low-temperature metamagnetic behaviour.« less

Recent Results for the ECHo Experiment

NASA Astrophysics Data System (ADS)

Hassel, C.; Blaum, K.; Goodacre, T. Day; Dorrer, H.; Düllmann, Ch. E.; Eberhardt, K.; Eliseev, S.; Enss, C.; Filianin, P.; Fäßler, A.; Fleischmann, A.; Gastaldo, L.; Goncharov, M.; Hengstler, D.; Jochum, J.; Johnston, K.; Keller, M.; Kempf, S.; Kieck, T.; Köster, U.; Krantz, M.; Marsh, B.; Mokry, C.; Novikov, Yu. N.; Ranitzsch, P. C. O.; Rothe, S.; Rischka, A.; Runke, J.; Saenz, A.; Schneider, F.; Scholl, S.; Schüssler, R. X.; Simkovic, F.; Stora, T.; Thörle-Pospiech, P.; Türler, A.; Veinhard, M.; Wegner, M.; Wendt, K.; Zuber, K.

2016-08-01

The Electron Capture in ^{163}Ho experiment, ECHo, is designed to investigate the electron neutrino mass in the sub-eV range by means of the analysis of the calorimetrically measured spectrum following the electron capture (EC) in ^{163}Ho. Arrays of low-temperature metallic magnetic calorimeters (MMCs), read-out by microwave SQUID multiplexing, will be used in this experiment. With a first MMC prototype having the ^{163}Ho source ion-implanted into the absorber, we performed the first high energy resolution measurement of the EC spectrum, which demonstrated the feasibility of such an experiment. In addition to the technological challenges for the development of MMC arrays, which preserve the single pixel performance in terms of energy resolution and bandwidth, the success of the experiment relies on the availability of large ultra-pure ^{163}Ho samples, on the precise description of the expected spectrum, and on the identification and reduction of background. We present preliminary results obtained with standard MMCs developed for soft X-ray spectroscopy, maXs-20, where the ^{163}Ho ion-implantation was performed using a high-purity ^{163}Ho source produced by advanced chemical and mass separation. With these measurements, we aim at determining an upper limit for the background level due to source contamination and provide a refined description of the calorimetrically measured spectrum. We discuss the plan for a medium scale experiment, ECHo-1k, in which about 1000 mathrm {Bq} of high-purity ^{163}Ho will be ion-implanted into detector arrays. With one year of measuring time, we will be able to achieve a sensitivity on the electron neutrino mass below 20 eV/c^2 (90 % C.L.), improving the present limit by more than one order of magnitude. This experiment will guide the necessary developments to reach the sub-eV sensitivity.

HO2 measurements at atmospheric concentrations using a chemical ionization mass spectrometry

NASA Astrophysics Data System (ADS)

Albrecht, S.; Novelli, A.; Hofzumahaus, A.; Kang, S.; Baker, Y.; Mentel, T. F.; Fuchs, H.

2017-12-01

Correct and precise measurements of atmospheric radical species are necessary for a better understanding of the oxidative capacity of the atmosphere. Due to the reactivity of radicals, and their consequent low concentrations, direct measurements of these species are particularly challenging and have been proven in the past to be affected by interfering species. Here we present a chemical ionization source coupled to an APi-HR-TOF-MS (Aerodyne Research Inc.), which has a limit of detection for HO2 radicals well below its atmospheric concentrations ( 1 x 108 molecules cm-3). The instrument was calibrated with a well-established and characterized HO2 calibration source in use for the laser induced fluorescence instrument in the Forschungszentrum Jülich. Within the source, a well characterized amount of HO2 radicals is produced after photolysis of water by a mercury lamp. In addition, several experiments were performed in the atmosphere simulation chamber SAPHIR at the Forschungszentrum Jülich to test for potential interferences. Measurements of HO2 radicals were concurrently detected by a laser induced fluorescence instrument allowing for the comparison of measurements within the two different and independent techniques for various atmospheric conditions regarding concentrations of O3, NOx and VOCs. Results from the intercomparison together with the calibration procedure of the instrument and laboratory characterization will be presented.

Mid-infrared lasing from Ho(3+) in bulk InF(3) glass.

PubMed

Berrou, Antoine; Kieleck, Christelle; Eichhorn, Marc

2015-04-15

We report on an Ho³⁺:InF₃ glass laser pumped by a Cr³⁺:LiSAF laser emitting at 889 nm. Ho³⁺:InF₃ glass is a promising material for direct mid-infrared lasers around 4 μm. To evaluate the performances of this new material, we compared it to an Ho³⁺:BYF crystalline laser pumped by the same source. At 650 mJ pump energy, 7.2 mJ (46 mJ) was obtained with Ho³⁺:InF₃ (Ho³⁺:BYF), respectively. This is, to the best of our knowledge, the first reported laser activity in this type of glass.

RNi2B2C (R = Ho, Dy, Tb and Pr) single crystals grown by the cold copper crucible method

NASA Astrophysics Data System (ADS)

Durán, A.; Munoz, E.; Bernès, S.; Escudero, R.

2000-08-01

Single crystals of RNi2B2C (R = Ho, Dy, Tb, Pr) have been grown on cold copper crucibles in a high-frequency induction furnace. As a result, shiny metallic and brittle platelike single crystals were obtained. They were examined by x-ray and scanning electron microscopy with WDX/EDX for local composition analysis and show a very good crystallographic structure and compositions. Resistivity and dc magnetic measurements were performed to study superconducting and magnetic properties. Besides known electronic properties of the RNi2B2C family, we report for the first time results for PrNi2B2C single crystals successfully obtained by this technique.

Ambient measurements of OH and HO2 radicals and the OH reactivity in and above the Borneo Rainforest

NASA Astrophysics Data System (ADS)

Heard, D. E.; Whalley, L. K.; Furneaux, K. L.; Edwards, P.; Commane, R.; Goddard, A.; Ingham, T.; Evans, M.

2008-12-01

Ground-based measurements of OH, HO2 and the OH reactivity have been made as part of the OP3 project that took place at the Bukit Atur Global Atmospheric Watch station in the Danum Valley forest conservation area in Sabah, Borneo in 2008. The project consisted of two intensive measurement periods in April and July. Aircraft measurements of OH and HO2 above the ground site were also performed and preliminary data will be presented. The OH and HO2 radicals exhibit a distinct diurnal profile, broadly following the j(O1D) profile that was measured simultaneously (daytime [OH] ~ 2 - 5 x 106 molecule cm-3, [HO2] ~ 1 - 1.5 x 108 molecule cm-3). NO, which peaked in the early morning hours ([NO] ~ 100 pptV) and isoprene, which peaked in the afternoon ([isoprene] ~ 2 - 5 ppbV) were found to influence the OH profile. Both OH and HO2 persisted into the night and were detectable even after j(O1D) had fallen to zero (nighttime [OH] ~ 2.5 x 105 molecule cm-3, [HO2] ~ 2 x 107 molecule cm-3), suggesting night-time radical sources. The OH reactivity tracked the isoprene concentration, exhibiting maximum reactivity just after midday when isoprene levels peaked. Zero dimensional models, using a variety of mechanisms, have been used to predict the [OH], [HO2] and the OH reactivity that were observed. The models, constrained with measured OH sources and sinks, are used to test the hypothesis that OH is recycled from isoprene oxidation in this low NOx environment

Quaternary borocarbides: New class of intermetallic superconductors

NASA Technical Reports Server (NTRS)

Nagarajan, R.; Gupta, L. C.; Dhar, S. K.; Mazumdar, Chandan; Hossain, Zakir; Godart, C.; Levy-Clement, C.; Padalia, B. D.; Vijayaraghavan, R.

1995-01-01

Our recent discovery of superconductivity (SC) in the four-element multiphase Y-Ni-B-C system at an elevated temperature (TC approximately 12 K) has opened up great possibilities of identifying new superconducting materials and generating new physics. Superconductivity with Tc (greater than 20 K) higher than that known so far in bulk intermetallics has been observed in multiphase Y-Pd-B-C and Th-Pd-B-C systems and a family of single phase materials RENi2B2C (RE= Y, rare earth) have been found. Our investigations show YNi2B2C to be a strong coupling hard type-II SC. HC2(T) exhibits an unconventional temperature dependence. Specific heat and magnetization studies reveal coexistence of SC and magnetism in RNi2B2C (R = Ho, Er, Tm) with magnetic ordering temperatures (Tc approximately 8 K, 10.5 K, 11 K and Tm approximately 5 K, approximately 7K, approximately 4 K respectively) that are remarkably higher than those in known magnetic superconductors . Mu-SR studies suggest the possibility of Ni atoms carrying a moment in TmNi2B2C. Resistivity results suggests a double re-entrant transition (SC-normal-SC) in HoNi2B2C. RENi2B2C (RE = Ce, Nd, Gd) do not show SC down to 4.2 K. The Nd- and Gd-compounds order magnetically at approximately 4.5 K and approximately 19.5 K, respectively. Two SC transitions are observed in Y-Pd-B-C (Tc approximately 22 K, approximately 10 K) and in Th-Pd-B-C (Tc approximately 20 K, approximately 14 K) systems, which indicate that there are at least two structures which support SC in these borocarbides. In our multiphase ThNi2B2C we observe SC at approximately 6 K. No SC was seen in multiphase UNi2B2C, UPd2B2C, UOs2Ge2C and UPd5B3C(0.35) down to 4.2 K. Tc in YNi2B2C is depressed by substitutions (Gd, Th and U at Y-sites and Fe, Co at Ni-sites).

Long-Term Holding Capacity of Statically Loaded Anchors in Cohesive Soils

DTIC Science & Technology

1979-01-01

Kos .,es. Hanoiver NH A.RMY~ I-N( IVIN’NLEI)-S. HunmsIlle AL: Finded-Sr. Huintsville. Al. ARMY L.N( \\%AAURWAY S EXP SIA ILihrar%. Vicksburg NIS ARNMY 1...8217CHNOIOG6Y long Beach. C’A(%\\ agnert P()RT11I.ANI) CLNI ENT ASSOC. SKO KIE. 11. )C0REL.Yt: Skokie It. (Rsch & Ic\\ Ilab. lib.) 57 Pki SCON CORP IO~ SON...Sa~ brook CTI R.Q. PALNMER Kaitua. HI ENERGY R&I ADI)N H. Sko \\% ho. %Aashington. DC( -1..’%. NI ERNIEI. %%ashingion D)C \\kNI lAI.BOT Orange CA 58

Injection-seeded operation of a Q-switched Cr,Tm,Ho:YAG laser

NASA Technical Reports Server (NTRS)

Henderson, Sammy W.; Hale, Charley P.; Magee, James R.

1991-01-01

Single-frequency Tm,Ho:YAG lasers operating near 2 microns are attractive sources for several applications including eye-safe laser radar (lidar) and pumping of AgGaSe2 parametric oscillators for efficient generation of longer wavelengths. As part of a program to develop a coherent lidar system using Tm,Ho:YAG lasers, a diode laser-pumped tunable CW single-longitudinal-mode (SLM) Cr:Tm:Ho:YAG laser and a flashlamp-pumped single-transverse-mode Q-switched Cr,Tm,Ho:YAG laser were developed. The CW laser was used to injection-seed the flashlamp-pumped laser, resulting in SLM Q-switched output. Operational characteristics of the CW and Q-switched lasers and injection-seeding results are reported.

Parameter selection with the Hotelling observer in linear iterative image reconstruction for breast tomosynthesis

NASA Astrophysics Data System (ADS)

Rose, Sean D.; Roth, Jacob; Zimmerman, Cole; Reiser, Ingrid; Sidky, Emil Y.; Pan, Xiaochuan

2018-03-01

In this work we investigate an efficient implementation of a region-of-interest (ROI) based Hotelling observer (HO) in the context of parameter optimization for detection of a rod signal at two orientations in linear iterative image reconstruction for DBT. Our preliminary results suggest that ROI-HO performance trends may be efficiently estimated by modeling only the 2D plane perpendicular to the detector and containing the X-ray source trajectory. In addition, the ROI-HO is seen to exhibit orientation dependent trends in detectability as a function of the regularization strength employed in reconstruction. To further investigate the ROI-HO performance in larger 3D system models, we present and validate an iterative methodology for calculating the ROI-HO. Lastly, we present a real data study investigating the correspondence between ROI-HO performance trends and signal conspicuity. Conspicuity of signals in real data reconstructions is seen to track well with trends in ROI-HO detectability. In particular, we observe orientation dependent conspicuity matching the orientation dependent detectability of the ROI-HO.

Flashlamp-pumped Ho:Tm:Cr:LuAG laser

NASA Technical Reports Server (NTRS)

Jani, Mahendra G. (Inventor); Barnes, Norman P. (Inventor); Murray, Keith E. (Inventor); Kokta, Milan R. (Inventor)

1997-01-01

A room temperature solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG host material doped with a concentration of about 0.35% Ho ions, about 5.57% Tm ions and at least about 1.01% Cr ions. A broadband energizing source such as a flashlamp is disposed transversely to the laser crystal to energize the Ho ions, Tm ions and Cr ions.

High-Field Magnetization Study of R_{2} {Fe}_{17} {N}_{2} R 2 Fe 17 N 2 ( R = {Ho} R = Ho and Er) Nitrides

NASA Astrophysics Data System (ADS)

Tereshina, I. S.; Tereshina-Chitrova, E. A.; Pelevin, I. A.; Doerr, M.; Law, J. M.; Verbetski, V. N.; Salamova, A. A.

2018-03-01

The structure and magnetic properties of the nitrided compounds R2Fe_{17}N2 (R = Ho and Er) are studied. The type of crystal structure Th2Ni_{17} is preserved upon nitrogenation, and the relative unit cell volume Δ V{/}V increase exceeds 6%. Magnetic studies are performed in fields up to 60 T at 4.2 K on aligned powder samples. Field-induced spin-reorientation (SR) transitions are observed in the M( H) curves of R2Fe_{17}N2. Unlike the parent R2Fe_{17} compounds, where the magnetization increases in steps as the field grows stronger, R2Fe_{17}N2 demonstrate a gradual increase in magnetization. It is indicative of the change of the SR transition from first to the second type. Extrapolation of magnetization curves to the theoretical value of magnetization in the forced ferromagnetic state yields the coefficient of the inter-sublattice R-Fe exchange interaction. The inter-sublattice exchange is found to decrease upon nitrogenation.

Development and performance characteristics of flash lamp pumped Yb:YAG, Cr:Tm:Ho:YAG, Er:Tm:Ho:YLF laser sources and investigation of their potential biological applications

NASA Astrophysics Data System (ADS)

Karadimitriou, N.; Klinkenberg, B.; Papadopoulos, D. N.; Serafetinides, A. A.

2007-07-01

Laser ablation for the formation of apodized patterns on intraocular lenses, as an alternative of the conventional injection molding, has been proved to be a very promising new technique. For the precise lenses ablation, the use of suitable laser wavelength and pulse duration, resulting in a small optical penetration depth in the lens and in confinement of the energy deposition in a small volume, as well as the reduced thermal damage to the surrounding tissue, is essential. Mid-infrared laser wavelengths, at which the organic biological simulators absorption coefficient is large, meet well the above conditions. Towards the complete understanding of the intraocular lens ablation procedure and therefore the choice of the optimum laser beam characteristics for the most accurate, efficient and safe surgical application, the comparative study of various mid-infrared laser sources is of great interest. In this work we investigate the potential of the development of three different mid-infrared laser sources, namely the Yb:YAG, the Cr:Tm:Ho:YAG and the Er:Tm:Ho:YLF laser, operating at 1029 nm, 2060 nm and 2080 nm respectively and their ability in forming patterns on biomaterials. Pumping was achieved with conventional Xe flash lamps in a double elliptical pump chamber. A properly designed Pulse-Forming- Network capable of delivering energy up to 800 J, in variable lamp illumination durations is used. Several hundreds of mJoules were achieved from the Yb:YAG laser oscillator and several Joules from the Ho:YAG and Ho:YLF laser oscillators. Free running and Q-switched laser operation studies and preliminary experiments on laser and biomaterials (biopolymers and animal tissues) interactions will be reported.

Measurements of HO2 chemical kinetics with a new detection method

NASA Technical Reports Server (NTRS)

Lee, L. C.; Manzanares, E. R.

1985-01-01

In this research program, HO2 was detected by the OH(A-X) photofragment from dissociative excitation of HO2 at 147 nm. This detection method was applied to measure the reaction rate constant of HO2 + O3. This reaction rate constant is needed for the understanding of stratospheric chemistry. Since C12 was used in the flow system, photoexcitation of C12 may produce fluorescence to interfere with the measurements. Thus, the photoexcitation process of C12 in the vacuum ultraviolet region was also examined in this research period using synchrotron radiation as a light source. The research results are summarized.

Ab initio molecular dynamics with enhanced sampling for surface reaction kinetics at finite temperatures: CH2 ⇌ CH + H on Ni(111) as a case study

NASA Astrophysics Data System (ADS)

Sun, Geng; Jiang, Hong

2015-12-01

A comprehensive understanding of surface thermodynamics and kinetics based on first-principles approaches is crucial for rational design of novel heterogeneous catalysts, and requires combining accurate electronic structure theory and statistical mechanics modeling. In this work, ab initio molecular dynamics (AIMD) combined with the integrated tempering sampling (ITS) method has been explored to study thermodynamic and kinetic properties of elementary processes on surfaces, using a simple reaction CH 2 ⇌ CH + H on the Ni(111) surface as an example. By a careful comparison between the results from ITS-AIMD simulation and those evaluated in terms of the harmonic oscillator (HO) approximation, it is found that the reaction free energy and entropy from the HO approximation are qualitatively consistent with the results from ITS-AIMD simulation, but there are also quantitatively significant discrepancies. In particular, the HO model misses the entropy effects related to the existence of multiple adsorption configurations arising from the frustrated translation and rotation motion of adsorbed species, which are different in the reactant and product states. The rate constants are evaluated from two ITS-enhanced approaches, one using the transition state theory (TST) formulated in terms of the potential of mean force (PMF) and the other one combining ITS with the transition path sampling (TPS) technique, and are further compared to those based on harmonic TST. It is found that the rate constants from the PMF-based TST are significantly smaller than those from the harmonic TST, and that the results from PMF-TST and ITS-TPS are in a surprisingly good agreement. These findings indicate that the basic assumptions of transition state theory are valid in such elementary surface reactions, but the consideration of statistical averaging of all important adsorption configurations and reaction pathways, which are missing in the harmonic TST, are critical for accurate description of thermodynamic and kinetic properties of surface processes. This work clearly demonstrates the importance of considering temperature effects beyond the HO model, for which the AIMD simulation in combination with enhanced sampling techniques like ITS provides a feasible and general approach.

PSEUDO-BINARY SYSTEMS INVOLVING RARE EARTH LAVES PHASES

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

Wernick, J.H.; Haszko, S.E.; Dorsi, D.

1962-06-01

The phase relations in a number of pseudo-binary systems involving rare earth Laves phases were determined. Complete series of cubic solid-solutions occur in the DyMn/sub 2/HoMn/sub 2/, HoMn/sub 2/-HoFe/sub 2/, DyMn/sub 2/-DyFe/ sub 2/, HoMn/sub 2/-HoAl/ sub 2/, TbMn/sub 2/TbAl/sub 2/, and DyMn/sub 2/-DyAl/ sub 2/ pseudobinary systems. Deviations from linearity in the lattice constants with composition occur in all these systems. Complete series of cubic solidsolutions also exist in the GdAl/sub 2/-ErAl/sub 2/, GdAl/sub 2/-PrAl/sub 2/ , GdAl/sub 2/-NdAl/sub 2/, GdAl/sub 2/-DyAl/sub 2/, TbAl/sub 2/-NdAl/sub 2/, and T bAl/sub 2/-DyAl/sub 2/ systems. For these systems, no deviation from linearitymore » occurs in the lattice constants. For the DyFe/sub 2/-DyAl/sub 2/ and DyCo/sub 2/- DyAl/sub 2/ systems, two new ternary phases, DyFeAl and DyCoAl, form and have the MgZn/sub 2/ structure. Their structures were determined from x-ray powder data only. The electronic state giving rise to the formation of these ternary phases is discussed qualitatively. For the DyMn/sub 2/TmMn/sub 2/ system, the range of composition in which the cubic MgCu/sub 2/ and hexagonal MgZn/sub 2/ structures exist are reported. No complete series of solid solutions or intermediate phases are formed in the DyNi/sub 2/-DyAl/sub 2/ system. (auth)« less

Peroxy Radical Measurements during the IRRONIC Field Project by C2H6 - NO Chemical Amplification

NASA Astrophysics Data System (ADS)

Wood, E. C. D.; Kundu, S.; Deming, B.; Lew, M.; Stevens, P. S.; Sklaveniti, S.; Dusanter, S.

2015-12-01

We present measurements of total peroxy radicals (HO2 + RO2) during the Indiana Radical, Reactivity and Ozone Production Intercomparison (IRRONIC) field project in Bloomington, Indiana during July 2015. Peroxy radicals were measured by chemical amplification using ethane and nitric oxide in dual PFA reaction chambers, and the amplification product NO2 was quantified by cavity attenuated phase shift spectroscopy. On sunny days mid-day peroxy radical mixing ratios were typically between 20 and 70 ppt and were well correlated with "HO2*" measured by the Indiana University Laser-Induced Fluorescence with Fluorescence Assay by Gas Expansion (IU-FAGE) instrument. The ratio of total peroxy radicals (UMass) to the IU-FAGE HO2* measurements was greater than two. We also describe results from an informal intercomparison of the two instruments' calibration sources, which are based on acetone photolysis (UMass) and water photolysis (IU). In addition to sampling the IU calibration source in "amplification" mode, the UMass instrument also separately quantified the HO2 mixing ratio in the IU calibration gas by reaction with excess NO and subsequent quantification of the NO2 produced.

Monte Carlo simulation of liver cancer treatment with 166Ho-loaded glass microspheres

NASA Astrophysics Data System (ADS)

da Costa Guimarães, Carla; Moralles, Maurício; Roberto Martinelli, José

2014-02-01

Microspheres loaded with pure beta-emitter radioisotopes are used in the treatment of some types of liver cancer. The Instituto de Pesquisas Energéticas e Nucleares (IPEN) is developing 166Ho-loaded glass microspheres as an alternative to the commercially available 90Y microspheres. This work describes the implementation of a Monte Carlo code to simulate both the irradiation effects and the imaging of 166Ho and 90Y sources localized in different parts of the liver. Results obtained with the code and perspectives for the future are discussed.

Tuning charge transfer in the LaTiO3/RO/LaNiO3 (R = rare-earth) superlattices by the rare-earth oxides interfaces from a first-principles calculation

NASA Astrophysics Data System (ADS)

Yao, Fen; Zhang, Lifang; Meng, Junling; Liu, Xiaojuan; Zhang, Xiong; Zhang, Wenwen; Meng, Jian; Zhang, Hongjie

2018-03-01

We investigate the internal charge transfer at the isopolar interfaces in LaTiO3/RO/LaNiO3 (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu) superlattices by means of density functional theory calculations. The charge transfer from Ti sites to Ni sites in all superlattices is induced by the electronegativity difference between the elements Ti and Ni, and the lanthanide oxides interfaces can modulate the amount of charge transfer. Comparison of the perovskite heterostructures with the different rare-earth interfaces shows that increasing the deviations of bond angles from 180.0° and the oxygen motions near the interfaces enhance charge transfer. The 4f electrons themselves of rare-earth elements have faint influences on charge transfer. In addition, the reasons why our calculated 4f states of Sm and Tm elements disagree with the experimental systems have been provided. It is hoped that all the calculated results could be used to design new functional nanoelectronic devices in perovskite oxides.

White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals

NASA Astrophysics Data System (ADS)

Li, Chenxia; Xu, Shiqing; Ye, Rengguang; Deng, Degang; Hua, Youjie; Zhao, Shilong; Zhuang, Songlin

2011-04-01

Ho3+/Tm3+/Yb3+ tri-doped glass ceramics with white light emitting have been developed and demonstrated. Pumped by 980 nm laser diode (LD), intensive red, green and blue up-conversions (UC) were obtained. The green emission is assigned to Ho3+ ion and the blue emission is assigned to Tm3+ ion, whereas the red emission is the combination contribution of the Ho3+ and Tm3+ ions. The RGB intensities could be adjusted by tuning the rare-earth ion concentration and pump power intensity. Thus, multicolor of the luminescence, including perfect white light with CIE-X=0.329 and CIE-Y=0.342 in the 1931 CIE chromaticity diagram can be obtained in 0.15 Ho3+/0.2Tm3+/3Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals pumped by a single infrared laser diode source of 980 nm at 500 mW. The up-conversion luminescence mechanism of Yb3+ sensitize Ho3+ and Tm3+ ions and the energy transfer from Ho3+ to Tm3+ in oxy-fluoride silicate glass ceramics were analyzed.

2-.mu.m fiber amplified spontaneous emission (ASE) source

NASA Technical Reports Server (NTRS)

Jiang, Shibin (Inventor); Wu, Jianfeng (Inventor); Geng, Jihong (Inventor)

2007-01-01

A 2-.mu.m fiber Amplified Spontaneous Emission (ASE) source provides a wide emission bandwidth and improved spectral stability/purity for a given output power. The fiber ASE source is formed from a heavy metal oxide multicomponent glass selected from germanate, tellurite and bismuth oxides and doped with high concentrations, 0.5-15 wt. %, thulium oxides (Tm.sub.2O.sub.3) or 0.1-5 wt% holmium oxides (Ho.sub.2O.sub.3) or mixtures thereof. The high concentration of thulium dopants provide highly efficient pump absorption and high quantum efficiency. Co-doping of Tm and Ho can broaden the ASE spectrum.

Production of heavy neutron-rich nuclei in transfer reactions within the dinuclear system model

NASA Astrophysics Data System (ADS)

Zhu, Long; Feng, Zhao-Qing; Zhang, Feng-Shou

2015-08-01

The dynamics of nucleon transfer processes in heavy-ion collisions is investigated within the dinuclear system model. The production cross sections of nuclei in the reactions 136Xe+208Pb and 238U+248Cm are calculated, and the calculations are in good agreement with the experimental data. The transfer cross sections for the 58Ni+208Pb reaction are calculated and compared with the experimental data. We predict the production cross sections of neutron-rich nuclei 165-168 Eu, 169-173 Tb, 173-178 Ho, and 181-185Yb based on the reaction 176Yb+238U. It can be seen that the production cross sections of the neutron-rich nuclei 165Eu, 169Tb, 173Ho, and 181Yb are 2.84 μb, 6.90 μb, 46.24 μb, and 53.61 μb, respectively, which could be synthesized in experiment.

Generation and Characterization of Human Heme Oxygenase-1 Transgenic Pigs

PubMed Central

Yang, Jaeseok; Cho, Bumrae; Hwang, Jong-Ik; Park, Sol Ji; Hurh, Sunghoon; Kim, Hwajung; Lee, Eun Mi; Ro, Han; Kang, Jung Taek; Kim, Su Jin; Won, Jae-Kyung; O'Connell, Philip J.; Kim, Hyunil; Surh, Charles D.; Lee, Byeong-Chun; Ahn, Curie

2012-01-01

Xenotransplantation using transgenic pigs as an organ source is a promising strategy to overcome shortage of human organ for transplantation. Various genetic modifications have been tried to ameliorate xenograft rejection. In the present study we assessed effect of transgenic expression of human heme oxygenase-1 (hHO-1), an inducible protein capable of cytoprotection by scavenging reactive oxygen species and preventing apoptosis caused by cellular stress during inflammatory processes, in neonatal porcine islet-like cluster cells (NPCCs). Transduction of NPCCs with adenovirus containing hHO-1 gene significantly reduced apoptosis compared with the GFP-expressing adenovirus control after treatment with either hydrogen peroxide or hTNF-α and cycloheximide. These protective effects were diminished by co-treatment of hHO-1 antagonist, Zinc protoporphyrin IX. We also generated transgenic pigs expressing hHO-1 and analyzed expression and function of the transgene. Human HO-1 was expressed in most tissues, including the heart, kidney, lung, pancreas, spleen and skin, however, expression levels and patterns of the hHO-1 gene are not consistent in each organ. We isolate fibroblast from transgenic pigs to analyze protective effect of the hHO-1. As expected, fibroblasts derived from the hHO-1 transgenic pigs were significantly resistant to both hydrogen peroxide damage and hTNF-α and cycloheximide-mediated apoptosis when compared with wild-type fibroblasts. Furthermore, induction of RANTES in response to hTNF-α or LPS was significantly decreased in fibroblasts obtained from the hHO-1 transgenic pigs. These findings suggest that transgenic expression of hHO-1 can protect xenografts when exposed to oxidative stresses, especially from ischemia/reperfusion injury, and/or acute rejection mediated by cytokines. Accordingly, hHO-1 could be an important candidate molecule in a multi-transgenic pig strategy for xenotransplantation. PMID:23071605

Generation and characterization of human heme oxygenase-1 transgenic pigs.

PubMed

Yeom, Hye-Jung; Koo, Ok Jae; Yang, Jaeseok; Cho, Bumrae; Hwang, Jong-Ik; Park, Sol Ji; Hurh, Sunghoon; Kim, Hwajung; Lee, Eun Mi; Ro, Han; Kang, Jung Taek; Kim, Su Jin; Won, Jae-Kyung; O'Connell, Philip J; Kim, Hyunil; Surh, Charles D; Lee, Byeong-Chun; Ahn, Curie

2012-01-01

Xenotransplantation using transgenic pigs as an organ source is a promising strategy to overcome shortage of human organ for transplantation. Various genetic modifications have been tried to ameliorate xenograft rejection. In the present study we assessed effect of transgenic expression of human heme oxygenase-1 (hHO-1), an inducible protein capable of cytoprotection by scavenging reactive oxygen species and preventing apoptosis caused by cellular stress during inflammatory processes, in neonatal porcine islet-like cluster cells (NPCCs). Transduction of NPCCs with adenovirus containing hHO-1 gene significantly reduced apoptosis compared with the GFP-expressing adenovirus control after treatment with either hydrogen peroxide or hTNF-α and cycloheximide. These protective effects were diminished by co-treatment of hHO-1 antagonist, Zinc protoporphyrin IX. We also generated transgenic pigs expressing hHO-1 and analyzed expression and function of the transgene. Human HO-1 was expressed in most tissues, including the heart, kidney, lung, pancreas, spleen and skin, however, expression levels and patterns of the hHO-1 gene are not consistent in each organ. We isolate fibroblast from transgenic pigs to analyze protective effect of the hHO-1. As expected, fibroblasts derived from the hHO-1 transgenic pigs were significantly resistant to both hydrogen peroxide damage and hTNF-α and cycloheximide-mediated apoptosis when compared with wild-type fibroblasts. Furthermore, induction of RANTES in response to hTNF-α or LPS was significantly decreased in fibroblasts obtained from the hHO-1 transgenic pigs. These findings suggest that transgenic expression of hHO-1 can protect xenografts when exposed to oxidative stresses, especially from ischemia/reperfusion injury, and/or acute rejection mediated by cytokines. Accordingly, hHO-1 could be an important candidate molecule in a multi-transgenic pig strategy for xenotransplantation.

Wavelet-Transform-Based Power Management of Hybrid Vehicles with Multiple On-board Energy Sources Including Fuel Cell, Battery and Ultracapacitor

DTIC Science & Technology

2008-09-12

considered to be promising for application as distributed generation sources due to high efficiency and compactness [1-2], [21-24]. The PEMFC is...also a primary candidate for environment-friendly vehicles. The nomenclatures of the PEMFC are as follows: B , C : Constants to calculate the...0 O H H-O H-O 1 2 N I q q r r FU = (10) The block diagram of the PEMFC model based on the above equations is shown in Fig

Peroxy radical measurements with NCAR's chemical amplifier

NASA Technical Reports Server (NTRS)

Cantrell, Christopher; Shetter, Richard; Calvert, Jack G.

1994-01-01

The present NCAR instrument for HO2/RO2 measurements has been described previously. It is based on the reactions involving HO2, RO2, and HO radicals with CO and NO. Since (HO2) + (RO2) + (HO) is much greater than (HO) for most atmospheres, it is useful as a peroxy radical detector. Operation of the instrument depends on the creation of a chemical chain reaction which is initiated as HO2 and RO2 radicals in ambient air encounter added NO gas; this forms an NO2 molecule and an HO or RO radical: HO2(RO2) + NO yields HO(RO) + NO2. RO radicals react relatively efficiently with O2 to form an HO2 radical, and subsequently an HO-radical, by reaction with NO. CO gas added to the reaction chamber during part of the operating cycle, recycles the HO to HO2; HO + CO (+O2) yields HO2 + CO2. The reaction sequence may form several hundred NO2 molecules per HO2 (RO2) originally present, before chain termination occurs. The added CO is replaced by N2 addition periodically so that the chain reaction is suppressed, and a 'blank' signal resulting from NO2, O3 and possibly other NO2-forming species (non-chain processes) in ambient air is recorded. The difference between the signal with and without CO is proportional to the peroxy radical concentration. The NO2 produced is monitored using a sensitive luminol chemiluminescence detector system. In the NCAR instrument the length of the amplification chain is determined using a stable source of HO2 radicals (H2O2 thermal decomposition); the ratio of the signal seen with CO present to that with N2 present gives the sensitivity of the instrument to HO2 (molecules of NO2 formed/peroxy radical). The instrument is automated to carry out in hourly repeated cycles: (1) chain length determination; (2) NO2 calibration; and (3) linearity check on the response of signals. One minute averages of signals are normally recorded. The sensitivity of the instrument to detect peroxy radicals is in the pptv range. The present instrument has operated continuously (24 hr/day) in the field studies which extended over a period of several weeks. The major advantages of this instrument are as follows: (1) its relative simplicity; (2) low power requirements; and (3) its rapid response to all types of peroxy radicals--HO2, CH3O2 and the higher alkyl and acyl peroxy radicals; however not all RO2 species generate HO2 radicals with perfect efficiency and hence have somewhat lower response/molecule than HO2 radicals.

Ho3+ doped fluoroaluminate glass fibers for 2.9 µm lasing

NASA Astrophysics Data System (ADS)

Jia, S. J.; Jia, Z. X.; Yao, C. F.; Wang, S. B.; Jiang, H. W.; Zhang, L.; Feng, Y.; Qin, G. S.; Ohishi, Y.; Qin, W. P.

2018-01-01

Ho3+ doped fluoroaluminate glass fibers based on chemically durable AlF3-BaF2-YF3-PbF2-MgF2-CaF2 glasses are fabricated by using a rod-in-tube method. By using an 84 cm long Ho3+-doped fluoroaluminate glass fiber as the gain medium and a 1120 nm fiber laser as the pump source, lasing at 2868 nm is obtained, the maximum unsaturated power is about 57 mW for a pump power of 1224 mW, and the corresponding slope efficiency is ~5.1%. The effect of the fiber length on lasing at 2868 nm is also investigated. Our results show that Ho3+-doped fluoroaluminate glass fibers are promising gain media for 2.9 µm laser applications.

Simple sonochemical synthesis of Ho2O3-SiO2 nanocomposites as an effective photocatalyst for degradation and removal of organic contaminant.

PubMed

Zinatloo-Ajabshir, Sahar; Mortazavi-Derazkola, Sobhan; Salavati-Niasari, Masoud

2017-11-01

In this work, highly photocatalytically active Ho 2 O 3 -SiO 2 nanocomposites have been designed and applied for decomposition of methylene blue pollutant. Ho 2 O 3 -SiO 2 nanocomposites have been produced by new, quick and facile sonochemical process with the aid of tetramethylethylenediamine as a novel basic agent for the first time. The effect of the kind of basic agent, ultrasonic time and dosage of Ho source on the grain size, photocatalytic behavior and shape of the Ho 2 O 3 -SiO 2 nanocomposites have been evaluated for optimization the production condition. FESEM, EDX, FT-IR, DRS, XRD and TEM have been applied to characterize the as-produced Ho 2 O 3 -SiO 2 nanocomposites. Use of the as-produced Ho 2 O 3 -SiO 2 nanocomposites as photocatalyst via destruction of methylene blue pollutant under UV illumination has been compared. It was observed that SiO 2 has notable impact on catalytic activity of holmium oxide photocatalyst for destruction. Introducing of SiO 2 to holmium oxide can enhance destruction efficiency of holmium oxide to methylene blue pollutant under ultraviolet light. Copyright © 2017 Elsevier B.V. All rights reserved.

The infrared counterpart of the eclipsing X-ray binary HO253 + 193

NASA Technical Reports Server (NTRS)

Zuckerman, B.; Becklin, E. E.; Mclean, I. S.; Patterson, Joseph

1992-01-01

We report the identification of the infrared counterpart of the pulsating X-ray source HO253 + 193. It is a highly reddened star varying in K light with a period near 3 hr, but an apparent even-odd effect in the light curve implies that the true period is 6.06 hr. Together with the recent report of X-ray eclipses at the latter period, this establishes the close binary nature of the source. Infrared minimum occurs at X-ray minimum, certifying that the infrared variability arises from the tidal distortion of the lobe-filling secondary. The absence of a point source at radio wavelengths, plus the distance derived from the infrared data, suggests that the binary system is accidentally located behind the dense core of the molecular cloud Lynds 1457. The eclipses and pulsations in the X-ray light curve, coupled with the hard X-ray spectrum and low luminosity, demonstrate that HO253 + 193 contains an accreting magnetic white dwarf, and hence belongs to the 'DQ Herculis' class of cataclysmic variables.

Influence of solution acidity and CaCl2 concentration on the removal of heavy metals from metal-contaminated rice soils.

PubMed

Kuo, S; Lai, M S; Lin, C W

2006-12-01

Soil washing is considered a useful technique for remediating metal-contaminated soils. This study examined the release edges of Cd, Zn, Ni, Cr, Cu or Pb in two contaminated rice soils from central Taiwan. The concentrations exceeding the trigger levels established by the regulatory agency of Taiwan were Cu, Zn, Ni and Cr for the Ho-Mei soil and Pb for the Nan-Tou soil. Successive extractions with HCl ranging from 0 to 0.2 M showed increased release of the heavy metals with declining pH, and the threshold pH value below which a sharp increase in the releases of the heavy metals was highest for Cd, Zn, and Ni (pH 4.6 to 4.9), intermediate for Pb and Cu (3.1 to 3.8) and lowest for Fe (2.1), Al (2.2) and Cr (1.7) for the soils. The low response slope of Ni and Cr particularly for the rice soils make soil washing with the acid up to the highest concentration used ineffective to reduce their concentrations to below trigger levels. Although soil washing with 0.1 M HCl was moderately effective in reducing Cu, Pb, Zn and Cd, which brought pH of the soils to 1.1+/-0.1 (S.D.), the concurrent release of large quantities of Fe and Al make this remediation technique undesirable for the rice soils containing high clay. Successive washings with 0.01 M HCl could be considered an alternative as the dissolution of Fe and Al was minimal, and between 46 to 64% of Cd, Zn, and Cu for the Ho-Mei soil and 45% of Pb in the Na-Tou soil were extracted after four successive extractions with this dilute acid solution. The efficacy of Cd extraction improved if CaCl2 was added to the acid solution. The correlation analysis revealed that Cr extracted was highly correlated (P < 0.001) with Fe extracted, whereas the Cu, Ni, Zn, Cd or Pb extracted was better correlated (P < 0.001) with Al than with Fe extracted. It is possible that the past seasonal soil flooding and drainage in the soils for rice production was conducive to incorporating Cr within the structure of Fe oxide, thereby making them extremely insoluble even in 0.2 M HCl solution. The formation of solid solution of Ni with Al oxide was also possible, making it far less extractable than Cd, Zn, Cu, or Pb with the acid concentrations used.

An advanced method of contributing emissions to short-lived chemical species (OH and HO2): the TAGGING 1.1 submodel based on the Modular Earth Submodel System (MESSy 2.53)

NASA Astrophysics Data System (ADS)

Rieger, Vanessa S.; Mertens, Mariano; Grewe, Volker

2018-06-01

To mitigate the human impact on climate change, it is essential to determine the contribution of emissions to the concentration of trace gases. In particular, the source attribution of short-lived species such as OH and HO2 is important as they play a crucial role for atmospheric chemistry. This study presents an advanced version of a tagging method for OH and HO2 (HOx) which attributes HOx concentrations to emissions. While the former version (V1.0) only considered 12 reactions in the troposphere, the new version (V1.1), presented here, takes 19 reactions in the troposphere into account. For the first time, the main chemical reactions for the HOx chemistry in the stratosphere are also regarded (in total 27 reactions). To fully take into account the main HO2 source by the reaction of H and O2, the tagging of the H radical is introduced. In order to ensure the steady-state assumption, we introduce rest terms which balance the deviation of HOx production and loss. This closes the budget between the sum of all contributions and the total concentration. The contributions to OH and HO2 obtained by the advanced tagging method V1.1 deviate from V1.0 in certain source categories. For OH, major changes are found in the categories biomass burning, biogenic emissions and methane decomposition. For HO2, the contributions differ strongly in the categories biogenic emissions and methane decomposition. As HOx reacts with ozone (O3), carbon monoxide (CO), reactive nitrogen compounds (NOy), non-methane hydrocarbons (NMHCs) and peroxyacyl nitrates (PAN), the contributions to these species are also modified by the advanced HOx tagging method V1.1. The contributions to NOy, NMHC and PAN show only little change, whereas O3 from biogenic emissions and methane decomposition increases in the tropical troposphere. Variations for CO from biogenic emissions and biomass burning are only found in the Southern Hemisphere.

Space station propulsion

NASA Technical Reports Server (NTRS)

Jones, Robert E.; Morren, W. Earl; Sovey, James S.; Tacina, Robert R.

1987-01-01

Two propulsion systems have been selected for the space station: gaseous H/O rockets for high thrust applications and the multipropellant resistojets for low thrust needs. These two thruster systems integrate very well with the fluid systems on the space station, utilizing waste fluids as their source of propellant. The H/O rocket will be fueled by electrolyzed water and the resistojets will use waste gases collected from the environmental control system and the various laboratories. The results are presented of experimental efforts with H/O and resistojet thrusters to determine their performance and life capability, as well as results of studies to determine the availability of water and waste gases.

78 FR 68465 - NiSource, Inc.; Record of Decision, Habitat Conservation Plan, Environmental Impact Statement...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

...-FF03E00000] NiSource, Inc.; Record of Decision, Habitat Conservation Plan, Environmental Impact Statement... to the Endangered Species Act of 1973, as amended (ESA). The ITP authorizes NiSource, Inc., to take... public of the availability of the ROD associated with an ITP application received from NiSource, Inc...

Electron microscopy study of Ni induced crystallization in amorphous Si thin films

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

Radnóczi, G. Z.; Battistig, G.; Pécz, B., E-mail: pecz.bela@ttk.mta.hu

2015-02-17

The crystallization of amorphous silicon is studied by transmission electron microscopy. The effect of Ni on the crystallization is studied in a wide temperature range heating thinned samples in-situ inside the microscope. Two cases of limited Ni source and unlimited Ni source are studied and compared. NiSi{sub 2} phase started to form at a temperature as low as 250°C in the limited Ni source case. In-situ observation gives a clear view on the crystallization of silicon through small NiSi{sub 2} grain formation. The same phase is observed at the crystallization front in the unlimited Ni source case, where a secondmore » region is also observed with large grains of Ni{sub 3}Si{sub 2}. Low temperature experiments show, that long annealing of amorphous silicon at 410 °C already results in large crystallized Si regions due to the Ni induced crystallization.« less

VizieR Online Data Catalog: Star-forming galaxies in near-IR (Martins+, 2013)

NASA Astrophysics Data System (ADS)

Martins, L. P.; Rodriguez-Ardila, A.; Diniz, S.; Riffel, R.; de Souza, R.

2014-10-01

The sample used here was presented in Martins et al. (2013MNRAS.431.1823M) and is a subset of the one presented in the magnitude-limited optical spectroscopic survey of nearby bright galaxies of Ho, Filippenko & Sargent (1995, Cat. J/ApJS/98/477, hereafter HO95). These galaxies are sources defined by Ho, Filippenko & Sargent (1997, Cat. J/ApJS/112/315, hereafter HO97) as those composed of 'nuclei dominated by emission lines from regions of active star formation (HII or starburst nuclei)'. In addition, five galaxies, classified as non-star forming in the optical, dominated by old stellar population and with no detected emission lines, were included as a control sample. All spectra were obtained at the NASA 3m Infrared Telescope Facility (IRTF) in two observing runs (2007 and 2008) - the same data from Martins et al. (2013MNRAS.431.1823M). (2 data files).

2  μm laser oscillation of Ho3+:Tm3+-codoped silica microspheres.

PubMed

Peng, Longxiang; Huang, Yantang; Duan, Yafan; Zhuang, Shijian; Liao, Tingdi; Xu, Canhua

2017-09-10

2 μm laser oscillation with a low threshold has been achieved in Ho 3+ :Tm 3+ -codoped silica microspheres (HTCSMs). Ho 3+ :Tm 3+ -codoped solgel functionalization film is applied to the surface of a silica microsphere, and an optical tapered fiber is adopted to couple an 808 nm continuous-wave laser to serve as the pump light source. Multimode and single-mode laser oscillations around 2 μm within the eye-safe wave band are observed due to the I 7 5→I 8 5 transitions of Ho 3+ ions sensitized by Tm 3+ . The morphology characteristics of microspheres determine the multimode laser oscillation spectrum. The free spectral range is in good accordance with the calculated value based on Mie scattering theory. The HTCSM laser oscillation shows characteristics of good capability, simple process, high flexibility, and low cost.

The diurnal variation of hydrogen, nitrogen, and chlorine radicals: Implications for the heterogeneous production of HNO2

NASA Technical Reports Server (NTRS)

Salawitch, R. J.; Wofsy, S. C.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.

1994-01-01

In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained through sunrise and sunset in the lower statosphere during SPADE are compared to results from a photochemical model constrained by observed concentrations of radical precursors and environmental conditions. Models allowing for heteogeneous hydrolysis of N2O5 on sulfate aerosols agree with measured concentrations of NO, NO2, and ClO throughout the day, but fail to account for high concentrations of OH and HO2 observed near sunrise and sunset. The morning burst of (OH) and (HO2) coincides with the rise of (NO) from photolysis of NO2, suggesting a new source of HO(x) that photolyzes in the near UV (350 to 400 nm) spectral region. A model that allow for the heterogeneous production of HNO2 results in an excellent simulation of the diurnal variations of (OH) and (HO2).

Hydrogen Radicals, Nitrogen Radicals, and the Production of O3 in the Upper Troposphere

NASA Technical Reports Server (NTRS)

Wennberg, P. O.; Hanisco, T. F.; Jaegle, L.; Jacob, D. J.; Hintsa, E. J.; Lanzendorf, E. J.; Anderson, J. G.; Gao, R.-S.; Keim, E. R.; Donnelly, S. G.;

Hydrogen Radicals, Nitrogen Radicals, and the Production of O3 in the Upper Troposphere

NASA Technical Reports Server (NTRS)

Wennberg, P. O.; Hanisco, T. F.; Jaegle, L.; Jacob, D. J.; Hintsa, E. J.; Lanzendorf, E. J.; Anderson, J. G.; Gao, R.-S.; Keim, E. R.; Donnelly, S. G.;

Yields of O2(b 1 Sigma g +) from reactions of HO2. [in planetary atmospheres

NASA Technical Reports Server (NTRS)

Keyser, L. F.; Choo, K. Y.; Leu, M. T.

1985-01-01

The production of O2(b 1 Sigma g +) has been monitored for several reactions of the HO2 radical at 300 K using a discharge-flow apparatus with resonance fluorescence and chemiluminescence detection. In all cases, the resulting quantum efficiencies were found to be less than 0.03. O2(b) was observed when F atoms were added to H2O2 in the gas phase. The signal strengths of O2(b) were proportional to initial concentrations of HO2 formed by the F + H2O2 reaction. Observed /O2(b)/, /HO2/, and /OH/ vs /F/0 were analyzed using a simple three-step mechanism and a more complete computer simulation with 22 reaction steps. The results indicate that the F + HO2 reaction yields O2(b) with an efficiency of (3.6 + or - 1.4) x 10 to the -3rd. Yields from the O + OH2 reaction were less than 0.02, indicating that this reaction cannot be a major source of the O2(b) emission observed in the earth's nightglow.

Atmospheric PCDD/F concentration and source apportionment in typical rural, Agent Orange hotspots, and industrial areas in Vietnam.

PubMed

Ngo, Tuan Hung; Hien, To Thi; Thuan, Ngo Thi; Minh, Nguyen Hung; Chi, Kai Hsien

2017-09-01

Vietnam has a double burden of dioxin from both industrial sources and historical sources. To evaluate the concentration of PCDD/Fs in ambient air in different areas of Vietnam and their possible sources, atmospheric samples were collected from three areas namely Son La (rural area) and Da Nang (harbor - Agent Orange hotspot area), and Ho Chi Minh City (metropolitan - industrial city). Vapor and solid phases of PCDD/Fs were collected and analyzed following the TO-9A sampling method. Principal Component Analysis and Positive Matrix Factorization model were applied to characterize the possible source. The average concentrations of PCDD/Fs were found to be 21.3 ± 13 fg I-TEQ/m 3 in Son La (n = 32), 65.2 ± 34 fg I-TEQ/m 3 in Da Nang (n = 16) and 139 ± 84 fg I-TEQ/m 3 in Ho Chi Minh City (n = 8). The findings of this study targeted open burning (42%) and biomass burning (51%) as the major emission sources of PCDD/Fs in ambient air of Son La, Vietnam. Major possible sources of PCDD/Fs in Da Nang could be transportation activities (64%), however, the other factor (36%) was suspected to be contaminated with 2,3,7,8-TeCDD from Agent Orange. Most of PCDD/Fs emitted in Ho Chi Minh City related to industrial activities (93%). Copyright © 2017 Elsevier Ltd. All rights reserved.

Holmium-doped fluorotellurite microstructured fibers for 2.1 μm lasing.

PubMed

Yao, Chuanfei; He, Chunfeng; Jia, Zhixu; Wang, Shunbin; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

2015-10-15

Holmium (Ho3+)-doped fluorotellurite microstructured fibers based on TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method. By using a 1.992 μm fiber laser as the pump source, lasing at 2.077 μm is obtained from a 27 cm long Ho3+-doped fluorotellurite microstructured fiber. The maximum unsaturated power is about 161 mW and the corresponding slope efficiency is up to 67.4%. The influence of fiber length on lasing at 2.1 μm is also investigated. Our results show that Ho3+-doped fluorotellurite microstructured fibers are promising gain media for 2.1 μm laser applications.

Adaptation of an In Situ Ground-Based Tropospheric OH/HO2 Instrument for Aircraft Use

NASA Technical Reports Server (NTRS)

Brune, William H.

1997-01-01

In-situ HO(x) (OH and HO2) measurements are an essential part of understanding the photochemistry of aircraft exhaust in the atmosphere. HO(x) affects the partitioning of nitrogen species in the NO(y) family. Its reactions are important sources and sinks for tropospheric ozone, thus providing a link between the NO(x) in aircraft exhaust and tropospheric ozone. OH mixing ratios are enhanced in aircraft wakes due to the photolysis of the HONO that is made close to the engine. Measurements of HO(x) in aircraft wakes, along with NO(x) measurements, thus provides a constraint on chemical models of the engine combustion and exhaust. The development of the Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) is reported. We designed, developed, and successfully flew this instrument. It was part of the instrument complement on board the NASA DC-8 during SUCCESS, which took place in Kansas in April and May, 1996. ATHOS has a limit-of-detection for OH (S/N = 2) of 10(exp 5) OH molecules cm(exp -3) in less than 150 seconds. While this sensitivity is about 2-3 times less than the initial projections in the proposal, it is more than adequate for good measurements of OH and HO2 from the planetary boundary layer to the stratosphere. Our participation in SUCCESS was to be engineering test flights for ATHOS; however, the high-quality measurements we obtained are being used to study HO(x) photochemistry in contrails, clouds, and the clear air.

Task Analysis Questionnaire Booklet, Occupational Field 60/61.

DTIC Science & Technology

1979-08-01

i ’ lELECT..... AUG 2 8 1980J DISTRIBUTION STATEME NT A ... - 8...S I ,, NOT A ’PEST ’Pique.;t. I ormvi i I . klesl) igne to obtna n I ’oriuation a h~ut your mil.Iitary job. The quesilons’ Wtoe coo~truct e fi-,’m, on-V...ho- J1!W :111,mAa laii nterolview2, w1th Mari no’ rzt-Cmi III- dut 102- 21_, I tO VoLI() z’,. TPo Properly i dent ifty tie ;ni 1 tary j ob.;

Missing Peroxy Radical Sources Within a Rural Forest Canopy

NASA Technical Reports Server (NTRS)

Wolfe, G. M.; Cantrell, C.; Kim, S.; Mauldin, R. L., III; Karl, T.; Harley, P.; Turnipseed, A.; Zheng, W.; Flocke, F.; Apel, E. C.;

Hydrogen Radicals, Nitrogen Radicals, and the Production of O3 in the Upper Troposphere

NASA Technical Reports Server (NTRS)

Wennberg, P. O.; Hanisco, T. F.; Jaegle, L.; Jacob, D. J.; Hintsa, E. J.; Lanzendorf, E. J.; Anderson, J. G.; Gao, R.-S.; Keim, E. R.; Donnelly, S. G.;

Global sensitivity analysis of GEOS-Chem modeled ozone and hydrogen oxides during the INTEX campaigns

NASA Astrophysics Data System (ADS)

Christian, Kenneth E.; Brune, William H.; Mao, Jingqiu; Ren, Xinrong

2018-02-01

Making sense of modeled atmospheric composition requires not only comparison to in situ measurements but also knowing and quantifying the sensitivity of the model to its input factors. Using a global sensitivity method involving the simultaneous perturbation of many chemical transport model input factors, we find the model uncertainty for ozone (O3), hydroxyl radical (OH), and hydroperoxyl radical (HO2) mixing ratios, and apportion this uncertainty to specific model inputs for the DC-8 flight tracks corresponding to the NASA Intercontinental Chemical Transport Experiment (INTEX) campaigns of 2004 and 2006. In general, when uncertainties in modeled and measured quantities are accounted for, we find agreement between modeled and measured oxidant mixing ratios with the exception of ozone during the Houston flights of the INTEX-B campaign and HO2 for the flights over the northernmost Pacific Ocean during INTEX-B. For ozone and OH, modeled mixing ratios were most sensitive to a bevy of emissions, notably lightning NOx, various surface NOx sources, and isoprene. HO2 mixing ratios were most sensitive to CO and isoprene emissions as well as the aerosol uptake of HO2. With ozone and OH being generally overpredicted by the model, we find better agreement between modeled and measured vertical profiles when reducing NOx emissions from surface as well as lightning sources.

Genetic differentiation of Mexican Holstein cattle and its relationship with Canadian and U.S. Holsteins

PubMed Central

García-Ruiz, Adriana; Ruiz-López, Felipe de J.; Van Tassell, Curtis P.; Montaldo, Hugo H.; Huson, Heather J.

2015-01-01

The Mexican Holstein (HO) industry has imported Canadian and US (CAN + USA) HO germplasm for use in two different production systems, the conventional (Conv) and the low income (Lowi) system. The objective of this work was to study the genetic composition and differentiation of the Mexican HO cattle, considering the production system in which they perform and their relationship with the Canadian and US HO populations. The analysis included information from 149, 303, and 173 unrelated or with unknown pedigree HO animals from the Conv, Lowi, and CAN + USA populations, respectively. Canadian and US Jersey (JE) and Brown Swiss (BS) genotypes (162 and 86, respectively) were used to determine if Mexican HOs were hybridized with either of these breeds. After quality control filtering, a total of 6,617 out of 6,836 single nucleotide polymorphism markers were used. To describe the genetic diversity across the populations, principal component (PC), admixture composition, and linkage disequilibrium (LD; r2) analyses were performed. Through the PC analysis, HO × JE and HO × BS crossbreeding was detected in the Lowi system. The Conv system appeared to be in between Lowi and CAN + USA populations. Admixture analysis differentiated between the genetic composition of the Conv and Lowi systems, and five ancestry groups associated to sire’s country of origin were identified. The minimum distance between markers to estimate a useful LD was found to be 54.5 kb for the Mexican HO populations. At this average distance, the persistence of phase across autosomes of Conv and Lowi systems was 0.94, for Conv and CAN + USA was 0.92 and for the Lowi and CAN + USA was 0.91. Results supported the flow of germplasm among populations being Conv a source for Lowi, and dependent on migration from CAN + USA. Mexican HO cattle in Conv and Lowi populations share common ancestry with CAN + USA but have different genetic signatures. PMID:25709615

Genetic differentiation of Mexican Holstein cattle and its relationship with Canadian and U.S. Holsteins.

PubMed

García-Ruiz, Adriana; Ruiz-López, Felipe de J; Van Tassell, Curtis P; Montaldo, Hugo H; Huson, Heather J

2015-01-01

The Mexican Holstein (HO) industry has imported Canadian and US (CAN + USA) HO germplasm for use in two different production systems, the conventional (Conv) and the low income (Lowi) system. The objective of this work was to study the genetic composition and differentiation of the Mexican HO cattle, considering the production system in which they perform and their relationship with the Canadian and US HO populations. The analysis included information from 149, 303, and 173 unrelated or with unknown pedigree HO animals from the Conv, Lowi, and CAN + USA populations, respectively. Canadian and US Jersey (JE) and Brown Swiss (BS) genotypes (162 and 86, respectively) were used to determine if Mexican HOs were hybridized with either of these breeds. After quality control filtering, a total of 6,617 out of 6,836 single nucleotide polymorphism markers were used. To describe the genetic diversity across the populations, principal component (PC), admixture composition, and linkage disequilibrium (LD; r(2) ) analyses were performed. Through the PC analysis, HO × JE and HO × BS crossbreeding was detected in the Lowi system. The Conv system appeared to be in between Lowi and CAN + USA populations. Admixture analysis differentiated between the genetic composition of the Conv and Lowi systems, and five ancestry groups associated to sire's country of origin were identified. The minimum distance between markers to estimate a useful LD was found to be 54.5 kb for the Mexican HO populations. At this average distance, the persistence of phase across autosomes of Conv and Lowi systems was 0.94, for Conv and CAN + USA was 0.92 and for the Lowi and CAN + USA was 0.91. Results supported the flow of germplasm among populations being Conv a source for Lowi, and dependent on migration from CAN + USA. Mexican HO cattle in Conv and Lowi populations share common ancestry with CAN + USA but have different genetic signatures.

Role of Yb3+ ions on enhanced ~2.9 μm emission from Ho3+ ions in low phonon oxide glass system

PubMed Central

Balaji, Sathravada; Gupta, Gaurav; Biswas, Kaushik; Ghosh, Debarati; Annapurna, Kalyandurg

2016-01-01

The foremost limitation of an oxide based crystal or glass host to demonstrate mid- infrared emissions is its high phonon energy. It is very difficult to obtain radiative mid-infrared emissions from these hosts which normally relax non-radiatively between closely spaced energy levels of dopant rare earth ions. In this study, an intense mid-infrared emission around 2.9 μm has been perceived from Ho3+ ions in Yb3+/Ho3+ co-doped oxide based tellurite glass system. This emission intensity has increased many folds upon Yb3+: 985 nm excitation compared to direct Ho3+ excitations due to efficient excited state resonant energy transfer through Yb3+: 2F5/2 → Ho3+: 5I5 levels. The effective bandwidth (FWHM) and cross-section (σem) of measured emission at 2.9 μm are assessed to be 180 nm and 9.1 × 10−21 cm2 respectively which are comparable to other crystal/glass hosts and even better than ZBLAN fluoride glass host. Hence, this Ho3+/Yb3+ co-doped oxide glass system has immense potential for the development of solid state mid-infrared laser sources operating at 2.9 μm region. PMID:27374129

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

Liu, Tianbiao L.; Wei, Xiaoliang; Nie, Zimin

The worldwide increasing energy demands and rising CO2 emissions motivate a search of new technologies to take advantage of renewable energy such as solar and wind. Rechargeable redox flow batteries (RFBs) with their high power density, high energy efficiency, scalability (up to MW and MWh), and safety features are one suitable option for integrating such energy sources and overcoming their intermittency. Source limitation and forbidden high system costs of current RFBs technologies impede wide implementation. Here we report a total organic aqueous redox flow battery (OARFB), using low cost and sustainable MV (anolyte) and 4-HO-TEMPO (catholyte), and benign NaCl supportingmore » electrolyte. The electrochemical properties of the organic redox active materials were studied using cyclic voltammetry and rotating disk electrode voltammetry. The MV/4-HO-TEMPO ARFB has an exceptionally high cell voltage, 1.25 V. Prototypes of the organic ARFB can be operated at high current densities ranging from 20 to 100 mA/cm2, and deliver stable capacity for 100 cycles with nearly 100% coulombic efficiency. The overall technical characters of the MV/4-HO-TEMPO ARFB are very attractive for continuous technic development.« less

Measurements of free radicals in a megacity during the Clean Air for London Project

NASA Astrophysics Data System (ADS)

Heard, Dwayne; Whalley, Lisa; Stone, Daniel; Clancy, Noel; Lee, James; Kleffman, Jorg; Laufs, Sebastian; Bandy, Brian

2013-04-01

Free radicals control the photo-oxidative chemistry of the atmosphere, being responsible for the transformation of primary emissions into secondary pollutants such as NO2, O3, multifunctional species and particulates. Here we present measurements of OH, HO2 and RO2 radicals and OH reactivity recorded at North Kensington, Central London, during two Intensive Operational Periods (IOPs) of the Clear Air for London (Clearflo) project in the summer and winter of 2012. OH and HO2 were measured using laser-induced fluorescence (LIF) spectroscopy at low pressure (the FAGE technique), and RO2 was measured using the recently developed ROXLIF technique, which utilises an external flow-reactor interfaced to FAGE, and which is able to discriminate between HO2 and organic peroxy radicals. Through control of reagent gases we are further able to provide a separate measurement of those RO2 species which are known to give an interference for HO2 measurements (namely alkene, aromatic and large-chain alkane derived RO2). OH reactivity was measured using laser-flash photolysis combined with FAGE. Low concentrations of radicals were observed during the winter IOP, with mixing ratios of [OH] ~ 0.04 pptv, [HO2] ~ 0.4 pptv, and [RO2] ~ 1.6 pptv at noon, all displaying a negative correlation with NO. The photolysis of O3 and subsequent reaction of O(1D) with H2O vapour was only a minor contribution to radical production in winter, with photolysis of HONO a major radical source. The summer IOP coincided with the London Olympic Games, with a number of pollution events, with ozone peaking at 100 ppbv (exceeding EU air quality directives) and elevated radical concentrations (peak [OH] ~ 0.14 pptv, [HO2] ~ 4 pptv, [RO2] ~ 6.4 pptv) being observed. The net rate of ozone production was calculated from radical observations and agreed well with measured ozone production, suggesting that advection/dilution by continental air-masses was not playing a significant role in determining ozone concentrations in London at that time. The ability to partially speciate RO2 enabled the contribution towards ozone production from different types of parent VOCs to be assessed. Steady-state analyses, using OH reactivity measurements to constrain the rate of loss of OH, gave reasonable agreement for [OH] but an additional HO2 sink was required to match [HO2]. The photolysis of HONO and carbonyl species and the decomposition of PAN were the dominant sources of radicals in London in summer.

Diode-Pumped Thulium (Tm)/Holmium (Ho) Composite Fiber 2.1-Micrometers Laser

DTIC Science & Technology

2015-09-01

composite fiber laser of holmium-core and thulium-doped cladding . The composite fiber was optically pumped by an 803-nm fiber coupled diode source and was...4 odd and 5 even modes were exclusive to the core and first cladding . As the Tm laser modes are excluded from lasing in the second (undoped...of the Tm-doped clad /Ho-doped core fiber laser . In particular, calculations of the model overlap of the cladding modes with the core have been

Comparison of reactant and analyte ions for ⁶³Nickel, corona discharge, and secondary electrospray ionization sources with ion mobility-mass spectrometry.

PubMed

Crawford, C L; Hill, H H

2013-03-30

(63)Nickel radioactive ionization ((63)Ni) is the most common and widely used ion source for ion mobility spectrometry (IMS). Regulatory, financial, and operational concerns with this source have promoted recent development of non-radioactive sources, such as corona discharge ionization (CD), for stand-alone IMS systems. However, there has been no comparison of the negative ion species produced by all three sources in the literature. This study compares the negative reactant and analyte ions produced by three sources on an ion mobility-mass spectrometer: conventional (63)Ni, CD, and secondary electrospray ionization (SESI). Results showed that (63)Ni and SESI produced the same reactant ion species while CD produced only the nitrate monomer and dimer ions. The analyte ions produced by each ion source were the same except for the CD source which produced a different ion species for the explosive RDX than either the (63)Ni or SESI source. Accurate and reproducible reduced mobility (K0) values, including several values reported here for the first time, were found for each explosive with each ion source. Overall, the SESI source most closely reproduced the reactant ion species and analyte ion species profiles for (63)Ni. This source may serve as a non-radioactive, robust, and flexible alternative for (63)Ni. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of iridium in mafic rocks by atomic absorption

USGS Publications Warehouse

Grimaldi, F.S.; Schnepfe, M.M.

1970-01-01

Iridium is determined in mineralized mafic rocks by atomic absorption after fire-assay concentration into a gold bead. Interelement interferences in the atomic-absorption determination are removed and Ir sensitivity is increased by buffering the solutions with a mixture of copper and sodium sulphates. Substantial amounts of Ag, Al, Au, Bi, Ca, Cd, Co, Cr, Fe, Ho, Hg, K, La, Mg, Mn, Mo, Ni, Pb, Te, Ti, V, Y, Zn and platinum metals can be tolerated in the atomic-absorption determination. The sensitivity and detection limits are 3.2 and 0.25 ppm of Ir, respectively. ?? 1970.

78 FR 34402 - Final Environmental Impact Statement, Habitat Conservation Plan, and Implementing Agreement...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-07

...-FF03E15000] Final Environmental Impact Statement, Habitat Conservation Plan, and Implementing Agreement, Ni... Environmental Impact Statement (FEIS) associated with an application received from NiSource Inc. (hereafter ``Ni... Endangered Species Act of 1973, as amended (ESA). If issued, the ITP would authorize NiSource to take 10...

Holder pasteurization affects S100B concentrations in human milk.

PubMed

Peila, Chiara; Coscia, Alessandra; Bertino, Enrico; Li Volti, Giovanni; Galvano, Fabio; Visser, Gerard H A; Gazzolo, Diego

2018-02-01

Donor milk (DM) represents an important nutrition source for high-risk newborns. Holder pasteurization (HoP) is the most recommended procedure for DM treatment, providing a good compromise between microbiological safety and biological quality. HoP was previously shown to affect DM cytokines, growth factors and hormones levels, whilst no data concerning the possible effects of HoP on neurobiomarkers (NB) are available. Therefore, our study investigated whether the concentration in DM of a well-known NB involved in brain development/damage, namely S100B, changes due to HoP. We conducted a pretest-test study in 11 mothers, whose DM samples were sub-divided into two parts: the first was immediately frozen (-80 °C); the second was pasteurized with Holder method before freezing. S100B DM levels were measured using a commercially available immunoluminometric assay. S100B protein was detected in all milk samples. Results showed significant differences between groups (p < 0.05) in S100B levels after HoP. Our data provide evidence that S100B is present in preterm milk as well as in term milk during maturation degree. Moreover, the results confirm the susceptibility of this neurotrophic factor to pasteurization stresses and the need to develop new storage techniques to preserve the biological quality of human milk.

Luminescence properties of long-lasting phosphor SrMg2(PO4)2:Eu2+, Ho3+, Zr4+

NASA Astrophysics Data System (ADS)

Tang, Wei; Wang, Mingwen; Lin, Wei; Ye, Yaping; Wu, Xue

2016-12-01

Novel long lasting phosphors SrMg2(PO4)2:Eu2+, SrMg2(PO4)2:Eu2+, Zr4+, SrMg2(PO4)2:Eu2+, Ho3+ and SrMg2(PO4)2:Eu2+, Ho3+, Zr4+ were synthesized by conventional solid-state reaction method. The luminescent properties were systematically characterized by X-ray diffraction, photoluminescent excitation and emission spectra, as well as thermoluminescence spectrum and decay curves. The XRD patterns indicated that the samples belonged to monoclinic phase and co-doping Eu2+, Ho3+ and Zr4+ ions had no effect on the basic crystal structure. These phosphors emitting purplish blue light is related to the characteristic emission of Eu2+. The afterglow time of Eu2+ activated SrMg2(PO4)2 can be greatly enhanced by the co-doping of Ho3+, Zr4+. After the 365 nm UV light excitation source switching off, the Sr0.92Mg1.95(PO4)2:Eu2+0.01, Zr4+0.05, Ho3+0.07 phosphorescence can be observed for more than 1013 s in the limit of light perception of dark-adapted human eyes (0.32 mcd/m2). Different kinds of TL peaks at 423, 448 and 473 K have appeared, and traps densities have increased compared with the Eu2+ single doped SrMg2(PO4)2 phosphor. By analyzing the TL curve the depths of traps were calculated to be 0.846, 0.896 and 0.946 eV, respectively, which suggested that the co-doping of Ho3+, Zr4+ improved the electron storage ability of material. Besides, the mechanism was discussed in this report.

Neutron scattering studies of the RENi 2B 2C (RE = Lu, Y, Ho, Er): Lattice dynamics

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

Bullock, Max

1998-02-23

The first chapter gives a brief overview of the system discussed in this dissertation. Chapters 2-5 and Appendix B of this dissertation consist of papers that are published, or have been submitted, which show experimental data regarding the phonon softening of LuNi 2B 2C. These papers have been removed and processed separately. Chapter 6 will contain a summary of the conclusions up to date. Appendix A will consist of a brief derivation of χ(q) which is talked about in the introduction of the dissertation. Appendix B will contain a Born-von Karman model fit to the experimental LuNi 2B 2C datamore » and a comparison with experimental data. Appendix C will contain a brief summary of the work done on LuNi 2B 2C as well as a complete listing of experimental data taken on the crystals which may be needed later for theoretical models of this system. Appendix D will outline a brief introduction covering some of the field theory used in the theoretical work for this thesis.« less

76 FR 41288 - Draft Environmental Impact Statement and Multi-Species Habitat Conservation Plan; Receipt of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

... for Incidental Take Permit; NiSource, Inc. AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice... NiSource, Inc. (Applicant), for an incidental take permit under the Endangered Species Act of 1973... have received an application from NiSource, Inc., for an incidental take permit (ITP) (TE02636A) under...

76 FR 63950 - Draft Environmental Impact Statement and Multi-Species Habitat Conservation Plan; Receipt of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-14

... for Incidental Take Permit; NiSource, Inc. AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice... (Service), are extending the public comment period on all documents related to NiSource, Inc.'s application... Register notice (76 FR 41288), we provided a list of 10 species for which NiSource, Inc. (the applicant...

Magnetic properties of epitaxial hexagonal HoFeO3 thin films

NASA Astrophysics Data System (ADS)

Wang, Xiao; Xiao, Zhuyun; Xu, Xiaoshan; Wang, Wenbin; Keavney, David; Liu, Yaohua; Cheng, X. M.

2014-03-01

Multiferroic materials exhibit multiple ferroic orders simultaneously and thus have great potential applications in information technology, sensing and actuation. Epitaxial hexagonal HoFeO3 (h-HFO) films are very promising candidates as multiferroic materials with room temperature ferromagnetism, because magnetic Ho3+ ions are expected to have stronger exchange interactions with Fe3+ ions than the well-studied h-LuFeO3 films. We report study of magnetic properties of epitaxial h-HFO thin films deposited using laser molecular beam epitaxy on Yttria-stabilized zirconia (YSZ) substrates. X-ray diffraction measurements confirmed the epitaxial registry and six-fold symmetry of the film. Temperature dependence of magnetization of the film measured by a Quantum Design SQUID magnetometer shows dominating paramagnetic characteristic. Element specific x-ray magnetic circular dichroism measurements performed at beamline 4-ID-C of the Advanced Photon Source show a ferromagnetic ordering of Fe and an exchange coupling between Ho3+ and Fe3+ ions. Work at BMC is supported by NSF Career award (DMR 1053854). Work at ANL is supported by US-DOE, Office of Science, BES (No. DE-AC02-06CH11357).

Application of groundwater sustainability indicators to the Upper Pliocene aquifer in Ho Chi Minh city, Viet Nam

NASA Astrophysics Data System (ADS)

Ngo, T. M.; Lee, J.; Lee, H.; Woo, N. C.

2013-12-01

Groundwater plays an importance role for domestic, industrial, and agricultural uses in Ho Chi Minh city, Viet Nam. This study is objected to evaluate the sustainability of groundwater by using groundwater sustainability indicators (GWSIs) defined by UNESCO/IAEA/IAH Working Group on Groundwater Indicators at aquifer scale (the Upper Pliocene aquifer). There are four main indicators selected and one new indicator designed for the particular characteristic of Ho Chi Minh city which is under influence of by saline-water intrusion. The results indicated groundwater of the Upper Pliocene aquifer, the main groundwater supply source, is generally in the unsustainable state. The abstraction of groundwater, which was much greater than its capability, is probably causing the serious state of annual groundwater depletion and saline-water intrusion. The GWSIs, which expressed in such a simple way but scientifically-based and policy-relevant, proved its usefulness in evaluating the sustainability of groundwater at the aquifer scale in Ho Chi Minh city, and subsequently should be incorporated in water resource management practices.

Ho-doped Soft Glass Optical Fibers for Coherent Wavelength Sources Above 2 Micron

DTIC Science & Technology

2010-12-01

following glasses were prepared in order to fabricate a single-mode Tm-Ho doped optical fibre. Their composition is in mol% and the rare earth oxides ...in this work was 99+%. The onset melting temperature was 750 ˚C and the duration of the process 2 hours. The melt was cast in a brass mould...preheated to 300 ˚C and annealed at Tg – 10 ˚C for 2 h. Glass melting was carried out in a Pt crucible inside a chamber furnace. Core glass was melted

Einstein’s quadrupole formula from the kinetic-conformal Hořava theory

NASA Astrophysics Data System (ADS)

Bellorín, Jorge; Restuccia, Alvaro

We analyze the radiative and nonradiative linearized variables in a gravity theory within the family of the nonprojectable Hořava theories, the Hořava theory at the kinetic-conformal point. There is no extra mode in this formulation, the theory shares the same number of degrees of freedom with general relativity. The large-distance effective action, which is the one we consider, can be given in a generally-covariant form under asymptotically flat boundary conditions, the Einstein-aether theory under the condition of hypersurface orthogonality on the aether vector. In the linearized theory, we find that only the transverse-traceless tensorial modes obey a sourced wave equation, as in general relativity. The rest of variables are nonradiative. The result is gauge-independent at the level of the linearized theory. For the case of a weak source, we find that the leading mode in the far zone is exactly Einstein’s quadrupole formula of general relativity, if some coupling constants are properly identified. There are no monopoles nor dipoles in this formulation, in distinction to the nonprojectable Horava theory outside the kinetic-conformal point. We also discuss some constraints on the theory arising from the observational bounds on Lorentz-violating theories.

Evaluation of the molecular mechanisms associated with cytotoxicity and inflammation after pulmonary exposure to different metal-rich welding particles.

PubMed

Shoeb, Mohammad; Kodali, Vamsi; Farris, Breanne; Bishop, Lindsey M; Meighan, Terence; Salmen, Rebecca; Eye, Tracy; Roberts, Jenny R; Zeidler-Erdely, Patti; Erdely, Aaron; Antonini, James M

2017-08-01

Welding generates a complex aerosol of incidental nanoparticles and cytotoxic metals, such as chromium (Cr), manganese (Mn), nickel (Ni), and iron (Fe). The goal was to use both in vivo and in vitro methodologies to determine the mechanisms by which different welding fumes may damage the lungs. Sprague-Dawley rats were treated by intratracheal instillation (ITI) with 2.0 mg of gas metal arc-mild steel (GMA-MS) or manual metal arc-stainless steel (MMA-SS) fumes or saline (vehicle control). At 1, 3, and 10 days, bronchoalveolar lavage (BAL) was performed to measure lung toxicity. To assess molecular mechanisms of cytotoxicity, RAW264.7 cells were exposed to both welding fumes for 24 h (0-100 μg/ml). Fume composition was different: MMA-SS (41% Fe, 29% Cr, 17% Mn, 3% Ni) versus GMA-MS (85% Fe, 14% Mn). BAL indicators of lung injury and inflammation were increased by MMA-SS at all time points and by GMA-MS at 3 and 10 days after exposure. RAW264.7 cells exposed to MMA-SS had elevated generation of reactive oxygen species (ROS), protein-HNE (P-HNE) adduct formation, activation of ERK1/2, and expression of cyclooxygenase-2 (COX-2) compared to GMA-MS and control. Increased generation of ROS due to MMA-SS exposure was confirmed by increased expression of Nrf2 and heme oxygenase-1 (HO-1). Results of in vitro studies provide evidence that stainless steel welding fume mediate inflammatory responses via activation of ROS/P-HNE/ERK1/2/Nrf2 signaling pathways. These findings were corroborated by elevated expression of COX-2, Nrf2, and HO-1 in homogenized lung tissue collected 1 day after in vivo exposure.

Comparative Evaluation of Effects of Laser Modalities on Shear Bond Strengths of Veneering Porcelains to Laser Sintered Substructures: An In Vitro Study.

PubMed

Gorler, Oguzhan; Saygin, Aysegul Goze

2017-06-01

Laser modalities and direct metal laser sintering (DMLS) have a potential to enhance micromechanical bonding between dental super- and infrastructures. However, the effect of different manufacturing methods on the metal-ceramic bond strength needs further evaluation. We investigated the effect of surface treatment with Er:YAG, Nd:YAG, and Ho:YAG lasers on the shear bond strength (SBS) of high-fusion dental porcelains (Vita and G-Ceram) to infrastructures prepared with DMLS in vitro settings. Study specimens (n = 128) were randomly divided into study subsets (n = 8), considering treatment types applied on the surface of infrastructures, including sandblasting and selected laser modalities; infrastructure types as direct laser sintered (DLS) and Ni-Cr based; and superstructure porcelains as Vita and G-Ceram. The SBS test was performed to assess the effectiveness of surface modifications that were also examined with a stereo microscope. Considering laser procedure types, the highest SBS values were obtained by Er:YAG laser, followed by, with a decreasing efficiency, Ho:YAG laser and sandblasting procedures, and Nd:YAG laser procedure (p < 0.05). Nd:YAG laser decreases the bonding of Vita and G-Ceram in all the infrastructures compared with sandblasting. Considering porcelains, the highest SBS values were obtained by Vita (p < 0.05). Considering infrastructures, the highest SBS values were obtained by DMLS procedure (p < 0.05). The laser procedures caused surface irregularities as revealed by the stereo microscopic examination. In current experimental settings, Er:YAG laser applied to DLS infrastructure veneered with Vita porcelain increases bonding strength more distinctly, and Nd:YAG laser applied to Ni-Cr-based infrastructure veneered with G-Ceram porcelain alters bonding strength unfavorably.

Ni-Co laterite deposits

USGS Publications Warehouse

Marsh, Erin E.; Anderson, Eric D.

2011-01-01

Nickel-cobalt (Ni-Co) laterite deposits are an important source of nickel (Ni). Currently, there is a decline in magmatic Ni-bearing sulfide lode deposit resources. New efforts to develop an alternative source of Ni, particularly with improved metallurgy processes, make the Ni-Co laterites an important exploration target in anticipation of the future demand for Ni. This deposit model provides a general description of the geology and mineralogy of Ni-Co laterite deposits, and contains discussion of the influences of climate, geomorphology (relief), drainage, tectonism, structure, and protolith on the development of favorable weathering profiles. This model of Ni-Co laterite deposits represents part of the U.S. Geological Survey Mineral Resources Program's effort to update the existing models to be used for an upcoming national mineral resource assessment.

Nitrite reductase expression is regulated at the post-transcriptional level by the nitrogen source in Nicotiana plumbaginifolia and Arabidopsis thaliana.

PubMed

Crété, P; Caboche, M; Meyer, C

1997-04-01

Higher plant nitrite reductase (NiR) is a monomeric chloroplastic protein catalysing the reduction of nitrite, the product of nitrate reduction, to ammonium. The expression of this enzyme is controlled at the transcriptional level by light and by the nitrogen source. In order to study the post-transcriptional regulation of NiR, Nicotiana plumbaginifolia and Arabidopsis thaliana were transformed with a chimaeric NiR construct containing the tobacco leaf NiR1 coding sequence driven by the CaMV 35S RNA promoter. Transformed plants did not show any phenotypic difference when compared with the wild-type, although they overexpressed NiR activity in the leaves. When these plants were grown in vitro on media containing either nitrate or ammonium as sole nitrogen source, NiR mRNA derived from transgene expression was constitutively expressed, whereas NiR activity and protein level were strongly reduced on ammonium-containing medium. These results suggest that, together with transcriptional control, post-transcriptional regulation by the nitrogen source is operating on NiR expression. This post-transcriptional regulation of tobacco leaf NiR1 expression was observed not only in the closely related species N. plumbaginifolia but also in the more distant species A. thaliana.

Nox4 NADPH oxidase mediates oxidative stress and apoptosis caused by TNF-α in cerebral vascular endothelial cells

PubMed Central

Basuroy, Shyamali; Bhattacharya, Sujoy; Leffler, Charles W.; Parfenova, Helena

2009-01-01

Inflammatory brain disease may damage cerebral vascular endothelium leading to cerebral blood flow dysregulation. The proinflammatory cytokine TNF-α causes oxidative stress and apoptosis in cerebral microvascular endothelial cells (CMVEC) from newborn pigs. We investigated contribution of major cellular sources of reactive oxygen species to endothelial inflammatory response. Nitric oxide synthase and xanthine oxidase inhibitors (Nω-nitro-l-arginine and allopurinol) had no effect, while mitochondrial electron transport inhibitors (CCCP, 2-thenoyltrifluoroacetone, and rotenone) attenuated TNF-α-induced superoxide (O2•−) and apoptosis. NADPH oxidase inhibitors (diphenylene iodonium and apocynin) greatly reduced TNF-α-evoked O2•− generation and apoptosis. TNF-α rapidly increased NADPH oxidase activity in CMVEC. Nox4, the cell-specific catalytic subunit of NADPH oxidase, is highly expressed in CMVEC, contributes to basal O2•− production, and accounts for a burst of oxidative stress in response to TNF-α. Nox4 small interfering RNA, but not Nox2, knockdown prevented oxidative stress and apoptosis caused by TNF-α in CMVEC. Nox4 is colocalized with HO-2, the constitutive isoform of heme oxygenase (HO), which is critical for endothelial protection against TNF-α toxicity. The products of HO activity, bilirubin and carbon monoxide (CO, as a CO-releasing molecule, CORM-A1), inhibited Nox4-generated O2•− and apoptosis caused by TNF-α stimulation. We conclude that Nox4 is the primary source of inflammation- and TNF-α-induced oxidative stress leading to apoptosis in brain endothelial cells. The ability of CO and bilirubin to combat TNF-α-induced oxidative stress by inhibiting Nox4 activity and/or by O2•− scavenging, taken together with close intracellular compartmentalization of HO-2 and Nox4 in cerebral vascular endothelium, may contribute to HO-2 cytoprotection against inflammatory cerebrovascular disease. PMID:19118162

Relationships between the structure of natural organic matter and its reactivity towards molecular ozone and hydroxyl radicals

USGS Publications Warehouse

Westerhoff, P.; Aiken, G.; Amy, G.; Debroux, J.

1999-01-01

Oxidation reaction rate parameters for molecular ozone (O3) and hydroxyl (HO) radicals with a variety of hydrophobic organic acids (HOAs) isolated from different geographic locations were determined from batch ozonation studies. Rate parameter values, obtained under equivalent dissolved organic carbon concentrations in both the presence and absence of non-NOM HO radical scavengers, varied as a function of NOM structure. First-order rate constants for O3 consumption (k(O3)) averaged 8.8 x 10-3 s-1, ranging from 3.9 x 10-3 s-1 for a groundwater HOA to > 16 x 10-3 s-1 for river HOAs with large terrestrial carbon inputs. The average second-order rate constant (k(HO,DOC) between HO radicals and NOM was 3.6 x 108 l (mol C)-1 s-1; a mass of 12 g C per mole C was used in all calculations. Specific ultraviolet absorbance (SUVA) at 254 or 280 nm of the HOAs correlated well (r > 0.9) with O3 consumption rate parameters, implying that organic ??-electrons strongly and selectively influence oxidative reactivity. HO radical reactions with NOM were less selective, although correlation between k(HO,DOC) and SUVA existed. Other physical-chemical properties of NOM, such as aromatic and aliphatic carbon content from 13C-NMR spectroscopy, proved less sensitive for predicting oxidation reactivity than SUVA. The implication of this study is that the structural nature of NOM varies temporally and spatially in a water source, and both the nature and amount of NOM will influence oxidation rates.

Ozone production in remote oceanic and industrial areas derived from ship based measurements of peroxy radicals during TexAQS 2006

NASA Astrophysics Data System (ADS)

Sommariva, R.; Brown, S. S.; Roberts, J. M.; Brookes, D. M.; Parker, A. E.; Monks, P. S.; Bates, T. S.; Bon, D.; de Gouw, J. A.; Frost, G. J.; Gilman, J. B.; Goldan, P. D.; Herndon, S. C.; Kuster, W. C.; Lerner, B. M.; Osthoff, H. D.; Tucker, S. C.; Warneke, C.; Williams, E. J.; Zahniser, M. S.

2011-03-01

During the Texas Air Quality Study II (TexAQS 2006) campaign, a PEroxy Radical Chemical Amplifier (PERCA) was deployed on the NOAA research vessel R/V Brown to measure total peroxy radicals (HO2+Σ RO2). Day-time mixing ratios of HO2+Σ RO2 between 25 and 110 ppt were observed throughout the study area - the Houston/Galveston region and the Gulf coast of the US - and analyzed in relation to measurements of nitrogen oxides, volatile organic compounds (VOC) and photolysis rates to assess radical sources and sinks in the region. The measurements of HO2+Σ RO2 were used to calculate the in-situ net photochemical formation of ozone. Measured median values ranged from 0.6 ppb/h in clean oceanic air masses up to several tens of ppb/h in the most polluted industrial areas. The results are consistent with previous studies and generally agree with observations made during the previous TexAQS 2000 field campaign. The net photochemical ozone formation rates determined at Barbours Cut, a site immediately south of the Houston Ship Channel, were analyzed in relation to local wind direction and VOC reactivity to understand the relationship between ozone formation and local VOC emissions. The measurements of HO2+Σ RO2 made during the R/V Brown TexAQS 2006 cruise indicate that ozone formation is NOx-limited in the Houston/Galveston region and influenced by highly reactive hydrocarbons, especially alkenes from urban and industrial sources and their photo-oxidation products, such as formaldehyde.

Ozone production in remote oceanic and industrial areas derived from ship based measurements of peroxy radicals during TexAQS 2006

NASA Astrophysics Data System (ADS)

Sommariva, R.; Brown, S. S.; Roberts, J. M.; Brookes, D. M.; Parker, A. E.; Monks, P. S.; Bates, T. S.; Bon, D.; de Gouw, J. A.; Frost, G. J.; Gilman, J. B.; Goldan, P. D.; Herndon, S. C.; Kuster, W. C.; Lerner, B. M.; Osthoff, H. D.; Tucker, S. C.; Warneke, C.; Williams, E. J.; Zahniser, M. S.

2010-10-01

During the Texas Air Quality Study II (TexAQS 2006) campaign, a PEroxy Radical Chemical Amplifier (PERCA) was deployed on the NOAA research vessel R/V Brown to measure total peroxy radicals (HO2+ΣRO2). Day-time mixing ratios of HO2+ΣRO2 between 25 and 110 ppt were observed throughout the study area - the Houston/Galveston region and the Gulf coast of the U.S. - and analyzed in relation to measurements of nitrogen oxides, volatile organic compounds (VOC) and photolysis rates to assess radical sources and sinks in the region. The measurements of HO2+ΣRO2 were used to calculate the in-situ net photochemical formation of ozone. Measured median values ranged from 0.6 ppb/h in clean oceanic air masses up to several tens of ppb/h in the most polluted industrial areas. The results are consistent with previous studies and generally agree with observations made during the previous TexAQS 2000 field campaign. The net photochemical ozone formation rates determined at Barbours Cut, a site immediately south of the Houston Ship Channel, were analyzed in relation to local wind direction and VOC reactivity to understand the relationship between ozone formation and local VOC emissions. The measurements of HO2+ΣRO2 made during the R/V Brown TexAQS 2006 cruise indicate that ozone formation is NOx-limited in the Houston/Galveston region and influenced by highly reactive hydrocarbons, especially alkenes from urban and industrial sources and their photooxidation products, such as formaldehyde.

A thermodynamic framework for understanding temperature sensing by transient receptor potential (TRP) channels

PubMed Central

Clapham, David E.; Miller, Christopher

2011-01-01

The exceptionally high temperature sensitivity of certain transient receptor potential (TRP) family ion channels is the molecular basis of hot and cold sensation in sensory neurons. The laws of thermodynamics dictate that opening of these specialized TRP channels must involve an unusually large conformational standard-state enthalpy, ΔHo: positive ΔHo for heat-activated and negative ΔHo for cold-activated TRPs. However, the molecular source of such high-enthalpy changes has eluded neurobiologists and biophysicists. Here we offer a general, unifying mechanism for both hot and cold activation that recalls long-appreciated principles of protein folding. We suggest that TRP channel gating is accompanied by large changes in molar heat capacity, ΔCP. This postulate, along with the laws of thermodynamics and independent of mechanistic detail, leads to the conclusion that hot- and cold-sensing TRPs operate by identical conformational changes. PMID:22109551

The Diurnal Variation of Hydrogen, Nitrogen, and Chlorine Radicals: Implications for the Heterogeneous Production of HNO2

NASA Technical Reports Server (NTRS)

Salawitch, R. J.; Wofsy, S. C.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.;

Bistability of Hydrogen in ZnO: Origin of Doping Limit and Persistent Photoconductivity

PubMed Central

Nahm, Ho-Hyun; Park, C. H.; Kim, Yong-Sung

2014-01-01

Substitutional hydrogen at oxygen site (HO) is well-known to be a robust source of n-type conductivity in ZnO, but a puzzling aspect is that the doping limit by hydrogen is only about 1018 cm−3, even if solubility limit is much higher. Another puzzling aspect of ZnO is persistent photoconductivity, which prevents the wide applications of the ZnO-based thin film transistor. Up to now, there is no satisfactory theory about two puzzles. We report the bistability of HO in ZnO through first-principles electronic structure calculations. We find that as Fermi level is close to conduction bands, the HO can undergo a large lattice relaxation, through which a deep level can be induced, capturing electrons and the deep state can be transformed into shallow donor state by a photon absorption. We suggest that the bistability can give explanations to two puzzling aspects. PMID:24535157

Bistability of hydrogen in ZnO: origin of doping limit and persistent photoconductivity.

PubMed

Nahm, Ho-Hyun; Park, C H; Kim, Yong-Sung

2014-02-18

Substitutional hydrogen at oxygen site (HO) is well-known to be a robust source of n-type conductivity in ZnO, but a puzzling aspect is that the doping limit by hydrogen is only about 10(18) cm(-3), even if solubility limit is much higher. Another puzzling aspect of ZnO is persistent photoconductivity, which prevents the wide applications of the ZnO-based thin film transistor. Up to now, there is no satisfactory theory about two puzzles. We report the bistability of HO in ZnO through first-principles electronic structure calculations. We find that as Fermi level is close to conduction bands, the HO can undergo a large lattice relaxation, through which a deep level can be induced, capturing electrons and the deep state can be transformed into shallow donor state by a photon absorption. We suggest that the bistability can give explanations to two puzzling aspects.

Official Guard and Reserve Manpower Strengths and Statistics. FY 2006 Summary

DTIC Science & Technology

2006-01-01

Summary is printed annually for each fiscal year. Comments concerned with policy issues of use of these reports for Reserve Component studies should...oinɛ ,c>jLn fllHHn-^kONMHdq’MT^nOfflHDWOOilHOniDiOCOOOCDCOtflOOOn’HlIltfltflOOJtOIN *£> Hor^cors] cNCD ^^^^iOi0^i/>^rsjrs]rnr^^ooinLn^rsjrn^r^^^oocDir...CN]oor-oocDir)^HCOo>CNCNtNcMr-oocoiT»1HLncor-cT» cNCD ^H^’mnrHro-q’rs]vco^Hr-^>^H «CT\\ioinmaicDiTiioniniDinHHCDmrjH\\OHCNi(\\incoh(N[vHO\\intn^’CN(NiN

Atomic-absorption determination of rhodium in chromite concentrates

USGS Publications Warehouse

Schnepfe, M.M.; Grimaldi, F.S.

1969-01-01

Rhodium is determined in chromite concentrates by atomic absorption after concentration either by co-precipitation with tellurium formed by the reduction of tellurite with tin(II) chloride or by fire assay into a gold bead. Interelement interferences in the atomic-absorption determination are removed by buffering the solutions with lanthanum sulphate (lanthanum concentration 1%). Substantial amounts of Ag, Al, Au, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ho, Hg, K, La, Mg, Mn, Mo, Na, Ni, Pb, Te, Ti, V, Y, Zn and platinum metals can be tolerated. A lower limit of approximately 0.07 ppm Rh can be determined in a 3-g sample. ?? 1969.

vVICTORIA Console Development: Design and Fabrication of VICTORIA Console Emulations

DTIC Science & Technology

2011-07-01

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Impacts of cloud water droplets on the OH production rate from peroxide photolysis.

PubMed

Martins-Costa, M T C; Anglada, J M; Francisco, J S; Ruiz-López, Manuel F

2017-12-06

Understanding the difference between observed and modeled concentrations of HO x radicals in the troposphere is a current major issue in atmospheric chemistry. It is widely believed that existing atmospheric models miss a source of such radicals and several potential new sources have been proposed. In recent years, interest has increased on the role played by cloud droplets and organic aerosols. Computer modeling of ozone photolysis, for instance, has shown that atmospheric aqueous interfaces accelerate the associated OH production rate by as much as 3-4 orders of magnitude. Since methylhydroperoxide is a main source and sink of HO x radicals, especially at low NO x concentrations, it is fundamental to assess what is the influence of clouds on its chemistry and photochemistry. In this study, computer simulations for the photolysis of methylhydroperoxide at the air-water interface have been carried out showing that the OH production rate is severely enhanced, reaching a comparable level to ozone photolysis.

Simple solution-combustion synthesis of Ni-NiO@C nanocomposites with highly electrocatalytic activity for methanol oxidation

NASA Astrophysics Data System (ADS)

Yu, Jie; Ni, Yonghong; Zhai, Muheng

2018-01-01

Transition metal and its oxide composite nanomaterials are attracting increasing research interest due to their superior properties and extensive applications in many fields. In this paper, Ni-NiO@C nanocomposites were successfully synthesized in one step via a simple solution-combustion route, employing NiCl2 as the Ni source, oxygen in the atmosphere as the oxygen source, and ethanol as the solvent. The final product was characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), (high resolution) transmission electron microscopy (TEM/HRTEM), and Raman spectra. N2 gas sorption-desorption experiments uncovered that the BET surface area of Ni-NiO@C nanocomposites reached 161.9 m2 g-1, far higher than 34.2 m2 g-1 of Ni-NiO. The electrochemical measurement showed that the as-produced Ni-NiO@C nanocomposites presented better catalytic activity for the electro-oxidation of methanol than Ni-NiO and NiO, which provides a new catalyst selection for the electro-oxidation of methanol.

Content and Composition of Branched-Chain Fatty Acids in Bovine Milk Are Affected by Lactation Stage and Breed of Dairy Cow

PubMed Central

Bainbridge, Melissa L.; Cersosimo, Laura M.; Wright, André-Denis G.; Kraft, Jana

2016-01-01

Dairy products contain bioactive fatty acids (FA) and are a unique dietary source of an emerging class of bioactive FA, branched-chain fatty acids (BCFA). The objective of this study was to compare the content and profile of bioactive FA in milk, with emphasis on BCFA, among Holstein (HO), Jersey (JE), and first generation HO x JE crossbreeds (CB) across a lactation to better understand the impact of these factors on FA of interest to human health. Twenty-two primiparous cows (n = 7 HO, n = 7 CB, n = 8 JE) were followed across a lactation. All cows were fed a consistent total mixed ration (TMR) at a 70:30 forage to concentrate ratio. Time points were defined as 5 days in milk (DIM), 95 DIM, 185 DIM, and 275 DIM. HO and CB had a higher content of n-3 FA at 5 DIM than JE and a lower n-6:n-3 ratio. Time point had an effect on the n-6:n-3 ratio, with the lowest value observed at 5 DIM and the highest at 185 DIM. The content of vaccenic acid was highest at 5 DIM, yet rumenic acid was unaffected by time point or breed. Total odd and BCFA (OBCFA) were higher in JE than HO and CB at 185 and 275 DIM. Breed affected the content of individual BCFA. The content of iso-14:0 and iso-16:0 in milk was higher in JE than HO and CB from 95 to 275 DIM. Total OBCFA were affected by time point, with the highest content in milk at 275 DIM. In conclusion, HO and CB exhibited a higher content of several bioactive FA in milk than JE. Across a lactation the greatest content of bioactive FA in milk occurred at 5 DIM and OBCFA were highest at 275 DIM. PMID:26930646

Content and Composition of Branched-Chain Fatty Acids in Bovine Milk Are Affected by Lactation Stage and Breed of Dairy Cow.

PubMed

Bainbridge, Melissa L; Cersosimo, Laura M; Wright, André-Denis G; Kraft, Jana

2016-01-01

Dairy products contain bioactive fatty acids (FA) and are a unique dietary source of an emerging class of bioactive FA, branched-chain fatty acids (BCFA). The objective of this study was to compare the content and profile of bioactive FA in milk, with emphasis on BCFA, among Holstein (HO), Jersey (JE), and first generation HO x JE crossbreeds (CB) across a lactation to better understand the impact of these factors on FA of interest to human health. Twenty-two primiparous cows (n = 7 HO, n = 7 CB, n = 8 JE) were followed across a lactation. All cows were fed a consistent total mixed ration (TMR) at a 70:30 forage to concentrate ratio. Time points were defined as 5 days in milk (DIM), 95 DIM, 185 DIM, and 275 DIM. HO and CB had a higher content of n-3 FA at 5 DIM than JE and a lower n-6:n-3 ratio. Time point had an effect on the n-6:n-3 ratio, with the lowest value observed at 5 DIM and the highest at 185 DIM. The content of vaccenic acid was highest at 5 DIM, yet rumenic acid was unaffected by time point or breed. Total odd and BCFA (OBCFA) were higher in JE than HO and CB at 185 and 275 DIM. Breed affected the content of individual BCFA. The content of iso-14:0 and iso-16:0 in milk was higher in JE than HO and CB from 95 to 275 DIM. Total OBCFA were affected by time point, with the highest content in milk at 275 DIM. In conclusion, HO and CB exhibited a higher content of several bioactive FA in milk than JE. Across a lactation the greatest content of bioactive FA in milk occurred at 5 DIM and OBCFA were highest at 275 DIM.

Base-Metal Electrode-Multilayer Ceramic Capacitors: Past, Present and Future Perspectives

NASA Astrophysics Data System (ADS)

Kishi, Hiroshi; Mizuno, Youichi; Chazono, Hirokazu

2003-01-01

Multilayer ceramic capacitor (MLCC) production and sales figures are the highest among fine-ceramic products developed in the past 30 years. The total worldwide production and sales reached 550 billion pieces and 6 billion dollars, respectively in 2000. In the course of progress, the development of base-metal electrode (BME) technology played an important role in expanding the application area. In this review, the recent progress in MLCCs with BME nickel (Ni) electrodes is reviewed from the viewpoint of nonreducible dielectric materials. Using intermediate-ionic-size rare-earth ion (Dy2O3, Ho2O3, Er2O3, Y2O3) doped BaTiO3 (ABO3)-based dielectrics, highly reliable Ni-MLCCs with a very thin layer below 2 μm in thickness have been developed. The effect of site occupancy of rare-earth ions in BaTiO3 on the electrical properties and microstructure of nonreducible dielectrics is studied systematically. It appears that intermediate-ionic-size rare-earth ions occupy both A- and B-sites in the BaTiO3 lattice and effectively control the donor/acceptor dopant ratio and microstructural evolution. The relationship between the electrical properties and the microstructure of Ni-MLCCs is also presented.

Hexanuclear, heterometallic, Ni₃Ln₃ complexes possessing O-capped homo- and heterometallic structural subunits: SMM behavior of the dysprosium analogue.

PubMed

Goura, Joydeb; Guillaume, Rogez; Rivière, Eric; Chandrasekhar, Vadapalli

2014-08-04

The reaction of hetero donor chelating mannich base ligand 6,6'-{(2-(dimethylamino)ethylazanediyl)bis(methylene)}bis(2-methoxy-4-methylphenol) with Ni(ClO4)2·6H2O and lanthanide(III) salts [Dy(III) (1); Tb(III) (2); Gd (III) (3); Ho(III) (4); and Er(III) (5)] in the presence of triethylamine and pivalic acid afforded a series of heterometallic hexanuclear Ni(II)-Ln(III) coordination compounds, [Ni3Ln3(μ3-O)(μ3-OH)3(L)3(μ-OOCCMe3)3]·(ClO4)·wCH3CN·xCH2Cl2·yCH3OH·zH2O [for 1, w = 8, x = 3, y = 0, z = 5.5; for 2, w = 0, x = 5, y = 0, z = 6.5; for 3, w = 15, x = 18, y = 3, z = 7.5; for 4, w = 15, x = 20, y = 6, z = 9.5; and for 5, w = 0, x = 3, y = 2, z = 3]. The molecular structure of these complexes reveals the presence of a monocationic hexanuclear derivative containing one perchlorate counteranion. The asymmetric unit of each of the hexanuclear derivatives comprises the dinuclear motif [NiLn(L)(μ3-O)(μ3-OH)(μ-Piv)]. The cation contains three interlinked O-capped clusters: one Ln(III)3O and three Ni(II)Ln(III)2O. Each of the lanthanide centers is eight- coordinated (distorted trigonal-dodecahedron), while the nickel centers are hexacoordinate (distorted octahedral). The study of the magnetic properties of all compounds are reported and suggests single molecule magnet behavior for the Dy(III) derivative (1).

Osmopriming-induced salt tolerance during seed germination of alfalfa most likely mediates through H2O2 signaling and upregulation of heme oxygenase.

PubMed

Amooaghaie, Rayhaneh; Tabatabaie, Fatemeh

2017-07-01

The present study showed that osmopriming or pretreatment with low H 2 O 2 doses (2 mM) for 6 h alleviated salt-reduced seed germination. The NADPH oxidase activity was the main source, and superoxide dismutase (SOD) activity might be a secondary source of H 2 O 2 generation during osmopriming or H 2 O 2 pretreatment. Hematin pretreatment similar to osmopriming improved salt-reduced seed germination that was coincident with the enhancement of heme oxygenase (HO) activity. The semi-quantitative RT-PCR confirmed that osmopriming or H 2 O 2 pretreatment was able to upregulate heme oxygenase HO-1 transcription, while the application of N,N-dimethyl thiourea (DMTU as trap of endogenous H 2 O 2 ) and diphenyleneiodonium (DPI as inhibitor of NADPHox) not only blocked the upregulation of HO but also reversed the osmopriming-induced salt attenuation. The addition of CO-saturated aqueous rescued the inhibitory effect of DMTU and DPI on seed germination and α-amylase activity during osmopriming or H 2 O 2 pretreatment, but H 2 O 2 could not reverse the inhibitory effect of ZnPPIX (as HO inhibitor) or Hb (as CO scavenger) that indicates that the CO acts downstream of H 2 O 2 in priming-driven salt acclimation. The antioxidant enzymes and proline synthesis were upregulated in roots of seedlings grown from primed seeds, and these responses were reversed by adding DMTU, ZnPPIX, and Hb during osmopriming. These findings for the first time suggest that H 2 O 2 signaling and upregulation of heme oxygenase play a crucial role in priming-driven salt tolerance.

External self-gettering of nickel in float zone silicon wafers

NASA Astrophysics Data System (ADS)

Gay, N.; Martinuzzi, S.

1997-05-01

During indiffusion of Ni atoms in silicon crystals at 950 °C from a nickel layer source, Ni-Si alloys can be formed close to the surface. Metal solubility in these alloys is higher than in silicon, which induces a marked segregation gettering of the Ni atoms which have diffused in the bulk of the wafers. Consequently, the regions of the wafers covered with the Ni layer are less contaminated than adjacent regions in which Ni atoms have also penetrated, as shown by the absence of precipitates and the higher diffusion length of minority carriers. The results suggest the existence of external self-gettering of Ni atoms by the nickel source.

A 10-year observation of PM2.5-bound nickel in Xi’an, China: Effects of source control on its trend and associated health risks

NASA Astrophysics Data System (ADS)

Xu, Hongmei; Ho, Steven Sai Hang; Cao, Junji; Guinot, Benjamin; Kan, Haidong; Shen, Zhenxing; Ho, Kin Fai; Liu, Suixin; Zhao, Zhuzi; Li, Jianjun; Zhang, Ningning; Zhu, Chongshu; Zhang, Qian; Huang, Rujin

2017-01-01

This study presents the first long term (10-year period, 2004-2013) datasets of PM2.5-bound nickel (Ni) concentration obtained from the daily sample in urban of Xi’an, Northwestern China. The Ni concentration trend, pollution sources, and the potential health risks associated to Ni were investigated. The Ni concentrations increased from 2004 to 2008, but then decreased due to coal consumption reduction, energy structure reconstruction, tighter emission rules and the improvement of the industrial and motor vehicle waste control techniques. With the comparison of distributions between workday and non-workday periods, the effectiveness of local and regional air pollution control policies and contributions of hypothetical Ni sources (industrial and automobile exhausts) were evaluated, demonstrating the health benefits to the populations during the ten years. Mean Ni cancer risk was higher than the threshold value of 10-6, suggesting that carcinogenic Ni still was a concern to the residents. Our findings conclude that there are still needs to establish more strict strategies and guidelines for atmospheric Ni in our living area, assisting to balance the relationship between economic growth and environmental conservation in China.

A Source Manual for Information on Nitinol and NiTi. First Revision

DTIC Science & Technology

1980-02-01

NSWC TR 80-59 A SOURCE MANUAL FOR INFORMATION ON NITINOL AND NiTi FIRST REVISION BY DAVID GOLDSTEIN RESEARCH AND TECHNOLOGY DEPARTMENT 1 FEBRUARY...NITINOL AND (9 . NiTi / lFirst Revisiony’?91 6 PERFORMINO ORG. WFWTRUM5ER Davi a CONTRACT OR GRANT NUMBER(. 9 PERFORMING ORGANIZATION NAME AND ADDRESS 10...NITINOL Nickel-Titanium Alloys NiTi Shape Memory Effect Heat Engines 20. ABSTRACT (Continue on roeore side if noceseary ansd Identify by block nuebstr

A Source Manual for Information on NITINOL and NiTi

DTIC Science & Technology

1978-02-13

NSWC/WOL TR 78-26/ A SOURCE MANUAL FOR INFORMATION ON <z NITINOL AND NiTi BY DAVID GOLDSTEIN RESEARCH AND TECHNOLOGY DEPARTMENT 13 FEBRUARY 1978 C...Conthinua owevess, side it necessary and identity by bWeck ammmber) NITINOL Nickel-Titanium Alloys NiTi Shape Memory Effect Heat Engines W0. A WRACT...Conshnue an reverse Wde Ifftoeseat and Identify by Weoek nmmer) This manual is a current listing of most of the published literature on NITINOL and NiTi

Comparison of ONIX simulation results with experimental data from the BATMAN testbed for the study of negative ion extraction

NASA Astrophysics Data System (ADS)

Mochalskyy, Serhiy; Fantz, Ursel; Wünderlich, Dirk; Minea, Tiberiu

2016-10-01

The development of negative ion (NI) sources for the ITER neutral beam injector is strongly accompanied by modelling activities. The ONIX (Orsay Negative Ion eXtraction) code simulates the formation and extraction of negative hydrogen ions and co-extracted electrons produced in caesiated sources. In this paper the 3D geometry of the BATMAN extraction system, and the source characteristics such as the extraction and bias potential, and the 3D magnetic field were integrated in the model. Calculations were performed using plasma parameters experimentally obtained on BATMAN. The comparison of the ONIX calculated extracted NI density with the experimental results suggests that predictive calculations of the extraction of NIs are possible. The results show that for an ideal status of the Cs conditioning the extracted hydrogen NI current density could reach ~30 mA cm-2 at 10 kV and ~20 mA cm-2 at 5 kV extraction potential, with an electron/NI current density ratio of about 1, as measured in the experiments under the same plasma and source conditions. The dependency of the extracted NI current on the NI density in the bulk plasma region from both the modeling and the experiment was investigated. The separate distributions composing the NI beam originating from the plasma bulk region and the PG surface are presented for different NI plasma volume densities and NI emission rates from the plasma grid (PG) wall, respectively. The extracted current from the NIs produced at the Cs covered PG surface, initially moving towards the bulk plasma and then being bent towards the extraction surfaces, is lower compared to the extracted NI current from directly extracted surface produced ions.

Cloning and characterization of a heme oxygenase-2 gene from alfalfa (Medicago sativa L.).

PubMed

Fu, Guang-Qing; Jin, Qi-Jiang; Lin, Yu-Ting; Feng, Jian-Fei; Nie, Li; Shen, Wen-Biao; Zheng, Tian-Qing

2011-11-01

Heme oxygenase (HO, EC 1.14.99.3) catalyzes the oxidation of heme and performs vital roles in plant development and stress responses. Two HO isozymes exist in plants. Between these, HO-1 is an oxidative stress-response protein, and HO-2 usually exhibited constitutive expression. Although alfalfa HO-1 gene (MsHO1) has been investigated previously, HO2 is still poorly understood. In this study, we report the cloning and characterization of HO2 gene, MsHO2, from alfalfa (Medica sativa L.). The full-length cDNA of MsHO2 contains an ORF of 870 bp and encodes for 290 amino acid residues with a predicted molecular mass of 33.3 kDa. Similar to MsHO1, MsHO2 also appears to have an N-terminal transit peptide sequence for chloroplast import. Many conserved residues in plant HO were also conserved in MsHO2. However, unlike HO-1, the conserved histidine (His) required for heme-iron binding and HO activity was replaced by tyrosine (Tyr) in MsHO2. Further biochemical activity analysis of purified mature MsHO2 showed no HO activity, suggesting that MsHO2 may not be a true HO in nature. Semi-quantitative RT-PCR confirmed its maximum expression in the germinating seeds. Importantly, the expression levels of MsHO2 were up-regulated under sodium nitroprusside (SNP) and H(2)O(2) (especially) treatment, respectively.

One-step facile synthesis of Ni2P/C as cathode material for Ni/Zn aqueous secondary battery

NASA Astrophysics Data System (ADS)

Li, JiLan; Chen, ChangGuo

2018-01-01

Nickel phosphides/carbon(Ni2P/C) composites have been successfully synthesized via a simple one-pot hydrothermal method using glucose as carbon source for the first time. By contrast, the pure Ni2P was prepared under the same conditions without glucose. The results show that glucose not only provide the carbon source, but also prevent the aggregation of Ni2P particles. The as-obtained Ni2P/C composites and pure Ni2P were used as cathode material for alkaline Ni/Zn battery. Owing to unique Ni2P/C composites and loose, Ultra thin flower-like shape the synthesized Ni2P/C material delivers high capacity of 176 mAh g-1 at 1 A g-1 and 82 mAh g-1 at 5 A g-1 current density in Ni2P/C-Zn battery. Moreover, it shows a good cycling life that capacity fading only about 6.2% after 1500 cycles. All of these indicate that the prepared Ni2P/C composites may be a new promising cathode material for Ni-Zn rechargeable battery.

Beyond the Classical Performance Limitations Controlling Uncertain MIMO Systems: UAV Applications. 2nd Session

DTIC Science & Technology

2008-05-01

en ts m et ho ds - 1s t fle xi bl e m od e ha s be en co ns id er ed fo re ac h be am an d al on g its X a nd Y...s b ee n pr es en te d. • Th e te ch ni qu e ha s b ee n va lid at ed w ith a D ar w in -ty pe sp ac ec ra ft w ith fle xi bl e ap pe nd ag es...2. 1 M ar io G ar ci a- Sa nz M ar io G ar ci a- Sa nz A

Sources of deactivation during glycerol conversion on Ni/γ-Al 2 O 3

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

Chimentão, R. J.; Miranda, B. C.; Szanyi, J.

Hydrogenolysis of glycerol was studied using a diluted aqueous solution of glycerol in gas phase and atmospheric pressure on Ni/γ-Al2O3 catalyst. The catalytic transformation of glycerol generates products derived from dehydration, dehydrogenation, hydrogenolysis and condensation reactions. Deep hydrogenolysis route to produce CH4 prevails in the first few hours of reaction. As the reaction time progress, dehydration-dehydrogenation products start to appear. Here, a description of the deactivation sources and its effects on the catalytic performance of Ni catalyst was proposed. The catalyst was characterized before and after the catalytic reaction by high-resolution transmission electron microscopy (HRTEM) and by employing Fourier transformedmore » infrared spectroscopy (FTIR) of adsorbed CO. A source of deactivation was due to carbonaceous deposition. FTIR at low CO dosing pressure reveal bands assignments species essentially due to linear and bridge carbonyls, whereas high pressure CO dosing produces a complex spectra due to polycarbonyls. X-ray absorption near edge structure (XANES) analysis was employed to reveal the initial degree of reduction of the fresh catalyst. The oxidation of metallic Ni in the course of reaction may also be considered as a source of deactivation. Ni oxide species promote dehydration routes. Alumina support facilitates nickel species to be more active toward interacting with glycerol. Dehydration, which takes place on the acid sites, is the mainly route related to the generation of carbon deposition and to the observed catalyst deactivation. Another source of deactivation was due to carbiding of Ni to form Ni3C. The regeneration of used Ni catalyst was achieved by oxidation-reduction steps at 723 K.« less

Ferroelectricity and competing interactions in Ho-deficient non-stoichiometric orthorhombic HoMnO{sub 3}

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

Wang, J. X.; Yan, Z. B.; Xie, Y. L.

2015-05-07

We investigate the consequences of the Ho-deficient non-stoichiometry in orthorhombic HoMnO{sub 3} in terms of microscopic mechanisms for ferroelectricity modulation. It is suggested that the Ho-deficiency (then Mn excess) results in Ho-vacancies and then Mn occupation of the Ho-site with increasing non-stoichiometry. The Ho-deficiency enhances the Mn-Mn symmetric exchange striction by suppressing the independent Ho-Ho interaction, and thus benefits to the induced Ho spin ordering against the independent Ho spin ordering. The symmetric Ho-Mn exchange striction is thus enhanced by this induced Ho spin ordering, leading to remarkably enhanced ferroelectric polarization as observed. This work presents an alternative scheme tomore » modulate the multiferroicity in rare-earth manganites of strong 4f-3d coupling.« less

A one-pot hydrothermal synthesis of 3D nitrogen-doped graphene aerogels-supported NiS2 nanoparticles as efficient electrocatalysts for the oxygen-reduction reaction

NASA Astrophysics Data System (ADS)

Yuan, Wen-Jing; Li, Ju-Chuan; Chen, Ping; Shen, Yu-Hua; Xie, An-Jian

2014-03-01

Nitrogen-doped graphene aerogels-supported NiS2 nanoparticles (NiS2/NG) were synthesized by a one-pot hydrothermal method. In the process, l-cysteine was used not only as the nitrogen source to form the nitrogen-doped graphene aerogels, but also the sulfur source to form NiS2. The nitrogen-doped graphene (NG) hybrids show an interconnected reticulation of NG sheets with uniform deposition of NiS2 NPs, and the NiS2 NPs are deposited on the NG layers. In studying the effects of the NG and NiS2/NG for the ORR, we found that NiS2/NG shows a more positive onset potential, higher current density, and higher electron transfer number (˜4) for the oxygen-reduction reaction (ORR) in alkaline media than NG. Furthermore, NiS2/NG shows better durability and methanol tolerance than the commercial Pt/C catalyst.

Peroxy Radical Measurements during PROPHET-AMOS 2016

NASA Astrophysics Data System (ADS)

Wood, E. C. D.; Deming, B.; Rollings, D.

2016-12-01

We present measurements of total peroxy radicals (HO2 + RO2) using the Ethane Chemical Amplifier (ECHAMP) technique during the PROPHET-AMOS project in Pellston, Michigan during July 2016. The C2H6/NO amplification chemistry occurred in FEP reaction chambers at the top of the PROPHET tower at a height of 34 m. The NO2 amplification product was transported through tubing to two cavity attenuated phase shift spectrometers (CAPS) housed inside the PROPHET laboratory. Two calibration sources were used: one based on water photolysis in the presence of isoprene and ozone actinometry, and another based on methyl iodide (CH3I) photolysis. The former was integrated into the inlet system, allowing for daily calibrations, whereas the latter was used twice during the campaign. Peak mixing ratios on warm, sunny days were approximately 40 ppt. Nighttime concentrations varied from below the instrumental detection limit to approximately 5 ppt. The measured peroxy radical concentrations will be compared to HO2 and HO2* mixing ratios measured by the Indiana University LIF-FAGE instrument.

Complementary rare earth element patterns in unique achondrites, such as ALHA 77005 and shergottites, and in the earth

NASA Technical Reports Server (NTRS)

Ma, M.-S.; Schmitt, R. A.; Laul, J. C.

1982-01-01

Abundances of major, minor, and trace elements are determined in the Antarctic achondrite Allan Hills (ALHA) 77005 via sequential instrumental and radiochemical neutron activation analysis. The rare earth element (REE) abundances of ALHA 77005 reveal a unique chondritic normalized pattern; that is, the REEs are nearly unfractionated from La to Pr at approximately 1.0X chondrites, monotonically increased from Pr to Gd at approximately 3.4X with no Eu anomaly, nearly unfractionated from Gd and Ho and monotonically decreased from Ho to Lu at approximately 2.2X. It is noted that this unique REE pattern of ALHA 77005 can be modeled by a melting process involving a continuous melting and progressive partial removal of melt from a light REE enriched source material. In a model of this type, ALHA 77005 could represent either a crystallized cumulate from such a melt or the residual source material. Calculations show that the parent liquids for the shergottites could also be derived from a light REE enriched source material similar to that for ALHA 77005.

Effects of a dietary antioxidant blend and vitamin E on fatty acid profile, liver function, and inflammatory response in broiler chickens fed a diet high in oxidants.

PubMed

Lu, T; Harper, A F; Zhao, J; Corl, B A; LeRoith, T; Dalloul, R A

2014-07-01

The aim of the current study was to determine the effects of a dietary antioxidant blend and vitamin E on fatty acid profile, inflammatory response, and liver function. Cobb 500 male broilers (n = 1,200, d 0) were randomly distributed into 6 treatments with 10 replicate floor pens. Treatments included (1) a high-oxidant diet, with vitamin E at 10 IU/kg, 3% oxidized oil, 3% polyunsaturated fatty acids (PUFA) source (HO); (2) the HO diet with vitamin E at 200 IU/kg (VE); (3) the HO diet with an antioxidant blend at 135 mg/kg (AOX); (4) the HO diet with both vitamin E at 200 IU/kg and an antioxidant blend at 135 mg/kg (VE+AOX); (5) standard control (SC); and (6) a positive control, which was the SC diet with an antioxidant blend at 135 mg/kg. The concentrations of 20:4, 20:5, 22:5, 22:6, and all the n-3 fatty acids were greater in the abdominal fat of HO, VE, AOX, and VE+AOX birds than SC and positive control birds on d 21 and 42 (P < 0.001). Compared with HO treatment, AOX and VE+AOX preserved the deposition of PUFA better (P < 0.001). The HO birds had greater concentrations of aspartate aminotransferase on d 21 and 42, and γ-glutamyl transferase on d 21, whereas AOX and VE+AOX chickens had restored γ-glutamyl transferase concentration (P < 0.01). The inflammation scores of abdominal fat of AOX and VE+AOX birds were lower than the HO on d 21 (P < 0.001). Compared with SC, the VE and VE+AOX birds exhibited greater vacuole scores on d 21 and 42 (P < 0.01). The lower vacuoles score in SC was associated with a greater expression of peroxisome proliferator activated receptor -γ and -α (P < 0.05). The expression of inflammatory genes in the liver did not differ among treatments. In conclusion, the AOX and AOX+VE diets were effective in preserving PUFA in the abdominal fat, moderately improved liver function, and reduced inflammation in fat. © 2014 Poultry Science Association Inc.

Magnetic biomonitoring of industrial air pollution in SW Finland

NASA Astrophysics Data System (ADS)

Salo, Hanna; Mäkinen, Joni

2015-04-01

Moss bags made of Sphagnum papillosum were exposed along 8 km transects near Harjavalta Industrial Park in SW Finland. Previous studies have identified Cu-Ni smelter's pipe as the main source of air pollution. Our research hypothesis is that nowadays the local pollution load of airborne particulate matter from Industrial Park is mainly caused by other emission sources than the smelter's pipe. To identify possible magnetic fingerprints, industrial samples (fiberglass filters from the smokestacks of Cu-Ni smelter and Ni-dryer, final Cu-slag, granulated Ni-slag, Cu-concentrates, Ni-concentrates) were investigated. Mass-specific susceptibility and heavy metal levels were significantly higher near Industrial Park and showed a decreasing trend with increasing distance from the source. The magnetic mineralogy of moss bags, smelter's filter and Cu-slag was dominated by a low-coercivity magnetite while high-coercivity minerals were observed in dryer's filter, Ni-slag and majority of concentrates including all Ni-concentrates. Angular and sharp-edged particles prevailed in moss bags and industrial samples, except for smelter's filter and granulated Ni-slag in which spherical particles dominated. Seven air pollution impact zones were distinguished around Industrial Park on the basis of magnetic susceptibility and previous studies. Overall, industrial area's influence is observable up to 4 km and even further distances in SE and NW along prevailing wind directions and Kokemäenjoki River valley. The heaviest anthropogenic air pollution load is deposited at 0.5-1 km distances. Particle morphology and magnetic data of the moss bags indicate that the particulate matter in the hot spot area, which spatial emphasis is in S-SW-W-NW in the upwind from the smelter, originate mainly from the dust emissions from other sources rather than the smelter's pipe. The industrial activities in and nearby hot spot area include handling and moving of concentrates and slags as well as heavy traffic. This study shows that air pollution from various dust-providing sources outweighs the fly-ash load from the Cu-Ni smelter's pipe especially at short distances. Furthermore, active magnetic monitoring by moss bags is spatially detailed sampling method for the identification of air pollutants and emission sources.

Concentrations and mass loadings of cardiovascular pharmaceuticals in healthcare facility wastewaters

EPA Science Inventory

Healthcare facilities are an under-characterized source of pharmaceuticals to municipal wastewaters. In this study, the composition and magnitude of 16 cardiovascular active pharmaceutical ingredients (API) and two cardiovascular API metabolites in wastewater effluents from a ho...

Photoluminescence properties of aeschynite-type LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) down-converting phosphors.

PubMed

Ma, Qian; Lu, Mengkai; Yang, Ping; Zhang, Aiyu; Cao, Yongqiang

2014-06-01

In this study, a series of LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) down-converting phosphors were synthesized using a modified sol-gel combustion method, and their photoluminescence (PL) properties were investigated as a function of activator concentration and annealing temperature. The resultant particles were characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, UV/Vis diffuse reflectance spectroscopy and PL spectra. The highly crystalline LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) phosphors with an average size of 200-300 nm obtained at 1100°C have an orthorhombic aeschynite-type structure and exhibit the highest luminescent intensity in our study range. The emission spectra of LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) phosphors under excitations at UV/blue sources are mainly composed of characteristic peaks arising from the f-f transitions of RE(3+), including 489 nm ((5) D4 → (7) F6) and 545 nm ((5) D4 → (7) F5) for Tb(3+), 476 and 482 nm ((4) F9/2 → (6) H15/2) and 571 nm ((4) F9/2 → (6) H13/2) for Dy(3+), and 545 nm ((5) F4 + (5) S2 → (5) I8) for Ho(3+), respectively. The luminescent mechanisms were further investigated. It can be expected that these phosphors are of intense interest and potential importance for many optical applications. Copyright © 2013 John Wiley & Sons, Ltd.

In vitro Activation of heme oxygenase-2 by menadione and its analogs

PubMed Central

2014-01-01

Background Previously, we reported that menadione activated rat, native heme oxygenase-2 (HO-2) and human recombinant heme oxygenase-2 selectively; it did not activate spleen, microsomal heme oxygenase-1. The purpose of this study was to explore some structure–activity relationships of this activation and the idea that redox properties may be an important aspect of menadione efficacy. Methods Heme oxygenase activity was determined in vitro using rat spleen and brain microsomes as the sources of heme oxygenase-1 and −2, respectively, as well as recombinant, human heme oxygenase-2. Results Menadione analogs with bulky aliphatic groups at position-3, namely vitamins K1 and K2, were not able to activate HO-2. In contrast, several compounds with similar bulky but less lipophilic moieties at position-2 (and −3) were able to activate HO-2 many fold; these compounds included polar, rigid, furan-containing naphthoquinones, furan-benzoxazine naphthoquinones, 2-(aminophenylphenyl)-3-piperidin-1-yl naphthoquinones. To explore the idea that redox properties might be involved in menadione efficacy, we tested analogs such as 1,4-dimethoxy-2-methylnaphthalene, pentafluoromenadione, monohalogenated naphthoquinones, α-tetralone and 1,4-naphthoquinone. All of these compounds were inactive except for 1,4-naphthoquinone. Menadione activated full-length recombinant human heme oxygenase-2 (FL-hHO-2) as effectively as rat brain enzyme, but it did not activate rat spleen heme oxygenase. Conclusions These observations are consistent with the idea that naphthoquinones such as menadione bind to a receptor in HO-2 and activate the enzyme through a mechanism that may involve redox properties. PMID:24533775

In vitro Activation of heme oxygenase-2 by menadione and its analogs.

PubMed

Vukomanovic, Dragic; Rahman, Mona N; Bilokin, Yaroslav; Golub, Andriy G; Brien, James F; Szarek, Walter A; Jia, Zongchao; Nakatsu, Kanji

2014-02-18

Previously, we reported that menadione activated rat, native heme oxygenase-2 (HO-2) and human recombinant heme oxygenase-2 selectively; it did not activate spleen, microsomal heme oxygenase-1. The purpose of this study was to explore some structure-activity relationships of this activation and the idea that redox properties may be an important aspect of menadione efficacy. Heme oxygenase activity was determined in vitro using rat spleen and brain microsomes as the sources of heme oxygenase-1 and -2, respectively, as well as recombinant, human heme oxygenase-2. Menadione analogs with bulky aliphatic groups at position-3, namely vitamins K1 and K2, were not able to activate HO-2. In contrast, several compounds with similar bulky but less lipophilic moieties at position-2 (and -3) were able to activate HO-2 many fold; these compounds included polar, rigid, furan-containing naphthoquinones, furan-benzoxazine naphthoquinones, 2-(aminophenylphenyl)-3-piperidin-1-yl naphthoquinones. To explore the idea that redox properties might be involved in menadione efficacy, we tested analogs such as 1,4-dimethoxy-2-methylnaphthalene, pentafluoromenadione, monohalogenated naphthoquinones, α-tetralone and 1,4-naphthoquinone. All of these compounds were inactive except for 1,4-naphthoquinone. Menadione activated full-length recombinant human heme oxygenase-2 (FL-hHO-2) as effectively as rat brain enzyme, but it did not activate rat spleen heme oxygenase. These observations are consistent with the idea that naphthoquinones such as menadione bind to a receptor in HO-2 and activate the enzyme through a mechanism that may involve redox properties.

Fracture toughness and the effects of stress state on fracture of nickel aluminides

NASA Technical Reports Server (NTRS)

Lewandowski, John J.; Michal, Gary M.; Locci, Ivan; Rigney, Joseph D.

1991-01-01

The effects of stress state on the fracture behavior of Ni3Al, Ni3Al + B, and NiAl were determined using either notched or fatigue-precracked bend bars tested to failure at room temperature, in addition to testing specimens in tension under superposed hydrostatic pressure. Although Ni3Al is observed to fail in a macroscopically brittle intergranular manner in tension tests conducted at room temperature, the fracture toughnesses presently obtained on Ni3Al exceeded 20 MPam, and R-curve behavior was exhibited. In situ monitoring of the fracture experiments was utilized to aid in interpreting the source(s) of the high toughness in Ni3Al, while SEM fractography was utilized to determine the operative fracture modes. The superposition by hydrostatic pressure during tensile testing of NiAl specimens was observed to produce increased ductility without changing the fracture mode.

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

PubMed Central

Benson, Nsikak U.; Asuquo, Francis E.; Williams, Akan B.; Essien, Joseph P.; Ekong, Cyril I.; Akpabio, Otobong; Olajire, Abaas A.

2016-01-01

Trace metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources. PMID:27257934

Extraordinarily large intrinsic magnetodielectric coupling of the Tb member within the Haldane spin-chain family R2BaNiO5

NASA Astrophysics Data System (ADS)

Upadhyay, Sanjay Kumar; Paulose, P. L.; Sampathkumaran, E. V.

2017-07-01

The Haldane spin-chain compound Tb2BaNiO5 has been known to order antiferromagnetically below (TN= )63 K . The present magnetic studies on the polycrystals bring out that there is another magnetic transition at a lower temperature (T2=)25 K with pronounced magnetic-field-induced metamagnetic and metaelectric behaviors. Multiferroic features are found below T2 only and not at TN. The most intriguing observation is that the observed change in dielectric constant (Δɛ') is intrinsic and largest (e.g., ˜18% at 15 K) within this Haldane spin-chain family R2BaNiO5 . Taking into account the fact that this trend (that is, the largest value of Δɛ' for the Tb case within this family) correlates well with a similar trend in TN (with the values of TN being ˜55, 58, 53, and 32 K for Gd, Dy, Ho, and Er cases), we believe that the explanation usually offered for this TN behavior in rare-earth systems is applicable for this Δɛ' behavior as well. That is, single-ion anisotropy following crystal-field splitting is responsible for the extraordinary magnetodielectric effect in this Tb case. This work provides a pathway in the field of multiferroics to promote magnetoelectric coupling.

Fine Structure in Multi-Phase Zr8Ni21-Zr7Ni10-Zr2Ni7 Alloy Revealed by Transmission Electron Microscope

PubMed Central

Shen, Haoting; Bendersky, Leonid A.; Young, Kwo; Nei, Jean

2015-01-01

The microstructure of an annealed alloy with a Zr8Ni21 composition was studied by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The presence of three phases, Zr8Ni21, Zr2Ni7, and Zr7Ni10, was confirmed by SEM/X-ray energy dispersive spectroscopy compositional mapping and TEM electron diffraction. Distribution of the phases and their morphology can be linked to a multi-phase structure formed by a sequence of reactions: (1) L → Zr2Ni7 + L’; (2) peritectic Zr2Ni7 + L’ → Zr2Ni7 + Zr8Ni21 + L”; (3) eutectic L” → Zr8Ni21 + Zr7Ni10. The effect of annealing at 960 °C, which was intended to convert a cast structure into a single-phase Zr8Ni21 structure, was only moderate and the resulting alloy was still multi-phased. TEM and crystallographic analysis of the Zr2Ni7 phase show a high density of planar (001) defects that were explained as low-energy boundaries between rotational variants and stacking faults. The crystallographic features arise from the pseudo-hexagonal structure of Zr2Ni7. This highly defective Zr2Ni7 phase was identified as the source of the broad X-ray diffraction peaks at around 38.4° and 44.6° when a Cu-K was used as the radiation source. PMID:28793460

Production and calving traits of Montbéliarde × Holstein and Viking Red × Holstein cows compared with pure Holstein cows during first lactation in 8 commercial dairy herds.

PubMed

Hazel, A R; Heins, B J; Hansen, L B

2017-05-01

Montbéliarde (MO) × Holstein (HO) and Viking Red (VR) × HO crossbred cows were compared with pure HO cows in 8 large, high-performance dairy herds. All cows were either 2-breed crossbred or pure HO cows that calved for the first time from December 2010 to April 2014. Best Prediction was used to calculate 305-d milk, fat, and protein production, as well as somatic cell score, and 513 MO × HO, 540 VR × HO, and 978 HO cows were analyzed for production in first lactation. Calving difficulty was scored from 1 (no assistance) to 5 (extreme difficulty). The analysis of calving traits included 493 MO × HO, 504 VR × HO, and 971 HO cows at first calving. Age at first calving was similar for breed groups, and the herds calved both crossbred (23.8 mo) and HO (23.9 mo) cows at young ages. The MO × HO crossbred cows had +3% higher production of 305-d fat plus protein production (actual basis, not mature equivalent) than the HO cows, and the VR × HO were similar to the HO cows for fat plus protein production. Breed groups did not differ for SCS during first lactation. The VR-sired 3-breed crossbred calves (from MO × HO dams) were similar to pure HO calves for calving difficulty; however, MO-sired male calves born to VR × HO dams had a mean score that was +0.5 points higher for calving difficulty than pure HO male calves. The 3-breed crossbred calves from both MO × HO (4%) and VR × HO (5%) first-lactation dams had a much lower stillbirth rate compared with pure HO calves (9%) from first-lactation dams. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Oxidative capacity of the Mexico City atmosphere - Part 1: A radical source perspective

NASA Astrophysics Data System (ADS)

Volkamer, R.; Sheehy, P. M.; Molina, L. T.; Molina, M. J.

2007-04-01

A detailed analysis of OH, HO2 and RO2 radical sources is presented for the near field photochemical regime inside the Mexico City Metropolitan Area (MCMA). During spring of 2003 (MCMA-2003 field campaign) an extensive set of measurements was collected to quantify time resolved ROx (sum of OH, HO2, RO2) radical production rates from day- and nighttime radical sources. The Master Chemical Mechanism (MCMv3.1) was constrained by measurements of (1) concentration time-profiles of photosensitive radical precursors, i.e., nitrous acid (HONO), formaldehyde (HCHO), ozone (O3), glyoxal (CHOCHO), and other oxygenated volatile organic compounds (OVOCs); (2) respective photolysis-frequencies (J-values); (3) concentration time-profiles of alkanes, alkenes, and aromatic VOCs (103 compound are treated) and oxidants, i.e., OH- and NO3 radicals, O3; and (4) NO, NO2, meteorological and other parameters. The ROx production rate was calculated directly from these observations; MCM was used to estimate further ROx production from unconstrained sources, and express overall ROx production as OH-equivalents (i.e., taking into account the propagation efficiencies of RO2 and HO2 radicals into OH radicals). Daytime radical production is found to be about 10-25 times higher than at night; it does not track the abundance of sunlight. 12-h average daytime contributions of individual sources are: HCHO and O3 photolysis, each about 20%; O3/alkene reactions and HONO photolysis, each about 15%; unmeasured sources about 30%. While the direct contribution of O3/alkene reactions appears to be moderately small, source-apportionment of ambient HCHO and HONO identifies O3/alkene reactions as being largely responsible for jump-starting photochemistry about one hour after sunrise. The peak radical production is found to be higher than in any other urban influenced environment studied to date; further, differences exist in the timing of radical production. Our measurements and analysis comprise a database that enables testing of the representation of radical sources in photochemical models. Since the photochemical processing of pollutants is radical-limited in the MCMA, our analysis identifies the drivers for such processing. Three pathways are identified by which reductions in VOC emissions induce reductions in peak concentrations of secondary pollutants, such as O3 and secondary organic aerosol (SOA).

Heterogeneous photochemistry of imidazole-2-carboxaldehyde: HO2 radical formation and aerosol growth

NASA Astrophysics Data System (ADS)

González Palacios, Laura; Corral Arroyo, Pablo; Aregahegn, Kifle Z.; Steimer, Sarah S.; Bartels-Rausch, Thorsten; Nozière, Barbara; George, Christian; Ammann, Markus; Volkamer, Rainer

2016-09-01

The multiphase chemistry of glyoxal is a source of secondary organic aerosol (SOA), including its light-absorbing product imidazole-2-carboxaldehyde (IC). IC is a photosensitizer that can contribute to additional aerosol ageing and growth when its excited triplet state oxidizes hydrocarbons (reactive uptake) via H-transfer chemistry. We have conducted a series of photochemical coated-wall flow tube (CWFT) experiments using films of IC and citric acid (CA), an organic proxy and H donor in the condensed phase. The formation rate of gas-phase HO2 radicals (PHO2) was measured indirectly by converting gas-phase NO into NO2. We report on experiments that relied on measurements of NO2 formation, NO loss and HONO formation. PHO2 was found to be a linear function of (1) the [IC] × [CA] concentration product and (2) the photon actinic flux. Additionally, (3) a more complex function of relative humidity (25 % < RH < 63 %) and of (4) the O2 / N2 ratio (15 % < O2 / N2 < 56 %) was observed, most likely indicating competing effects of dilution, HO2 mobility and losses in the film. The maximum PHO2 was observed at 25-55 % RH and at ambient O2 / N2. The HO2 radicals form in the condensed phase when excited IC triplet states are reduced by H transfer from a donor, CA in our system, and subsequently react with O2 to regenerate IC, leading to a catalytic cycle. OH does not appear to be formed as a primary product but is produced from the reaction of NO with HO2 in the gas phase. Further, seed aerosols containing IC and ammonium sulfate were exposed to gas-phase limonene and NOx in aerosol flow tube experiments, confirming significant PHO2 from aerosol surfaces. Our results indicate a potentially relevant contribution of triplet state photochemistry for gas-phase HO2 production, aerosol growth and ageing in the atmosphere.

Adapting TESLA technology for future cw light sources using HoBiCaT

NASA Astrophysics Data System (ADS)

Kugeler, O.; Neumann, A.; Anders, W.; Knobloch, J.

2010-07-01

The HoBiCaT facility has been set up and operated at the Helmholtz-Zentrum-Berlin and BESSY since 2005. Its purpose is testing superconducting cavities in cw mode of operation and it was successfully demonstrated that TESLA pulsed technology can be used for cw mode of operation with only minor changes. Issues that were addressed comprise of elevated dynamic thermal losses in the cavity walls, necessary modifications in the cryogenics and the cavity processing, the optimum choice of operational parameters such as cavity temperature or bandwidth, the characterization of higher order modes in the cavity, and the usability of existing tuners and couplers for cw.

Middle atmosphere heating by exothermic chemical reactions involving odd-hydrogen species

NASA Technical Reports Server (NTRS)

Mlynczak, Martin G.; Solomon, Susan

1991-01-01

The rate of heating which occurs in the middle atmosphere due to four exothermic reactions involving members of the odd-hydrogen family is calculated. The following reactions are considered: O + OH yields O2 + H; H + O2 + M yields HO2 + M; H + O3 yields OH + O2; and O + HO2 yields OH + O2. It is shown that the heating rates due to these reactions rival the oxygen-related heating rates conventionally considered in middle-atmosphere models. The conversion of chemical potential energy into molecular translational energy (heat) by these odd-hydrogen reactions is shown to be a significant energy source in the middle atmosphere that has not been previously considered.

Geology and lithogeochemistry of hydrothermal mudstones from the upper block near the Duck Pond volcanogenic massive sulfide (VMS) deposit, Newfoundland, Canada: evidence for low-temperature venting into oxygenated mid-Cambrian seawater

NASA Astrophysics Data System (ADS)

Piercey, Stephen J.; Squires, Gerry; Brace, Terry

2018-02-01

Pyrite- and pyrrhotite-rich mudstones are spatially associated with Cambrian ( 512-509 Ma) volcanogenic massive sulfide (VMS) deposits throughout the Tally Pond group, central Newfoundland, Canada. At the Duck Pond mine, sulfide-rich mudstones are hosted within a weakly mineralized upper block that structurally overlies the deposit but is older ( 513 versus 509 Ma). The mudstones are laminated, 10-30-cm thick, and pyrite- and pyrrhotite-rich and occur along pillow lava selvages, or in between pillow lavas, rhyolite flows, and volcaniclastic rocks. The mudstones are laterally extensive and proximal to the mudstone host rocks are hydrothermally altered to epidote-quartz-chlorite (basalt host) and sericite-quartz (rhyolite host). Lithogeochemical data for the sulfide-rich mudstones reflect the varying contributions of elements from sedimentary detritus, hydrothermal discharge, and hydrogenous scavenging from middle Cambrian seawater. The mudstones have minor detrital element abundances and significant hydrothermal element enrichments (i.e., elevated Fe2O3, S, Pb, Zn, Cu, and Ba concentrations, high Fe/Al ratios). The hydrothermal mudstones are also enriched in oxyanions (i.e., P2O5, U, V, Cr, Ni, Co, and Hg), interpreted to have been enriched via oxidative scavenging from seawater by Fe-oxide/oxyhydroxide particles. The mudstones also have REE-Y signatures similar to modern oxygenated seawater with high Y/Ho and negative Ce anomalies (Ce/Ce* = 0.40-0.86; average = 0.58), which correlate with adsorbed oxyanion concentrations. The low Eu/Eu* (1.02-1.86; average = 1.22) in the mudstones suggest that they were deposited from low-temperature (< 250 °C), Fe-rich hydrothermal fluids that likely formed a buoyant plume into an oxygenated water column. The REE-Y-oxyanion signatures suggest that the particles within the hydrothermal plume had sufficient residence time to scavenge oxyanions from seawater and inherit a middle Cambrian seawater signature. The predominant seawater REE-Y-oxyanion signature in the Duck Pond upper block sulfide-rich mudstones suggests that they are distal hydrothermal sedimentary rocks that could have formed up to 10 km from their original vent sources. Correspondingly, to utilize hydrothermal mudstones as vectors to mineralization in the Tally Pond belt, and similar belts globally, it is critical to identify vent-proximal samples that have hydrothermal signatures (i.e., high Fe/Al, base metals, Ba, S), with subdued seawater and adsorption signatures (i.e., chondritic Y/Ho, low P2O5, Ni, U, Co, Cr, V, and Hg), indicating minimal residence time in the water column and deposition proximal to the vent.

Prediction of 4H-SiC betavoltaic microbattery characteristics based on practical Ni-63 sources.

PubMed

Gui, Gui; Zhang, Kan; Blanchard, James P; Ma, Zhenqiang

2016-01-01

We have investigated the performance of 4H-SiC betavoltaic microbatteries under exposure to the practical Ni-63 sources using the Monte Carlo method and Synopsys® Medici device simulator. A typical planar p-n junction betavoltaic device with the Ni-63 source of 20% purity on top is modeled in the simulation. The p-n junction structure includes a p+ layer, a p- layer, an n+ layer, and an n- layer. In order to obtain an accurate and valid predication, our simulations consider several practical factors, including isotope impurities, self-absorption, and full beta energy spectra. By simulating the effects of both the p-n junction configuration and the isotope source thickness on the battery output performance, we have achieved the optimal design of the device and maximum energy conversion efficiency. Our simulation results show that the energy conversion efficiency increases as the doping concentration and thickness of the p- layer increase, whereas it is independent of the total depth of the p-n junction. Furthermore, the energy conversion efficiency decreases as the thickness of the practical Ni-63 source increases, because of self-absorption in the isotope source. Therefore, we propose that a p-n junction betavoltaic cell with a thicker and heavily doped p- layer under exposure to a practical Ni-63 source with an appreciable thickness could produce the optimal energy conversion efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cobalt internal standard for Ni to assist the simultaneous determination of Mo and Ni in plant materials by high-resolution continuum source graphite furnace atomic absorption spectrometry employing direct solid sample analysis.

PubMed

de Babos, Diego Victor; Bechlin, Marcos André; Barros, Ariane Isis; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta; de Oliveira, Silvana Ruella

2016-05-15

A new method is proposed for the simultaneous determination of Mo and Ni in plant materials by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS), employing direct solid sample analysis (DSS) and internal standardization (IS). Cobalt was used as internal standard to minimize matrix effects during Ni determinations, enabling the use of aqueous standards for calibration. Correlation coefficients for the calibration curves were typically better than 0.9937. The performance of the method was checked by analysis of six plant certified reference materials, and the results for Mo and Ni were in agreement with the certified values (95% confidence level, t-test). Analysis was made of different types of plant materials used as renewable sources of energy, including sugarcane leaves, banana tree fiber, soybean straw, coffee pods, orange bagasse, peanut hulls, and sugarcane bagasse. The concentrations found for Mo and Ni ranged from 0.08 to 0.63 ng mg(-1) and from 0.41 to 6.92 ng mg(-1), respectively. Precision (RSD) varied from 2.1% to 11% for Mo and from 3.7% to 10% for Ni. Limits of quantification of 0.055 and 0.074 ng were obtained for Mo and Ni, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Amomum tsao-ko suppresses lipopolysaccharide-induced inflammatory responses in RAW264.7 macrophages via Nrf2-dependent heme oxygenase-1 expression.

PubMed

Li, Bin; Choi, Hee-Jin; Lee, Dong-Sung; Oh, Hyuncheol; Kim, Youn-Chul; Moon, Jin-Young; Park, Won-Hwan; Park, Sun-Dong; Kim, Jai-Eun

2014-01-01

Amomum tsao-ko Crevost et Lemaire, used as a spice in Asia, is an important source of Chinese cuisine and traditional Chinese medicines. A. tsao-ko is reported to exert a variety of biological and pharmacological activities, including anti-proliferative, anti-oxidative and neuroprotective effects. In this study, NNMBS227, consisting of the ethanol extract of A. tsao-ko, exhibited potent anti-inflammatory activities in RAW264.7 macrophages. We investigated the effect of NNMBS227 in the suppression of pro-inflammatory mediators, including pro-inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2) and cytokines (tumor necrosis factor-α and interleukin-1β) in LPS stimulated macrophages. NNMBS227 also inhibited the phosphorylation and degradation of IκB-α, as well as the nuclear translocation of nuclear factor kappa B (NF-κB) p65 caused by stimulation with LPS. In addition, NNMBS227 induced heme oxygenase (HO)-1 expression through the nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) in macrophages. Using tin protoporphyrin (SnPP), an HO activity inhibitor, we confirmed an association between the anti-inflammatory effects of NNMBS227 and the up-regulation of HO-1. These findings suggest that Nrf2-dependent increases in the expression of HO-1 induced by NNMBS227 conferred anti-inflammatory activities in LPS stimulated RAW264.7 macrophages.

Testing Room-Temperature Ionic Liquid Solutions for Depot Repair of Aluminum Coatings

DTIC Science & Technology

2011-05-01

Ne 3 Na Mg IIIB IVB VB VIB VIIB ------ VIIIB ------ IB IIB Al Si P S Cl Ar 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 5 Rb Sr Y Zr Nb Mo Tc...Ru Rh Pd Ag Cd In Sn Sb Te I Xe 6 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 7 Fr Ra Ac Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np...Electroplating Bath Lid Arrangement ;:::::::::::=== Thermometer Purge gas vent Anode lead Cathode lead (Extractable from the lid) Purge feed gas

Heme Oxygenase-1 Regulates Matrix Metalloproteinase MMP-1 Secretion and Chondrocyte Cell Death via Nox4 NADPH Oxidase Activity in Chondrocytes

PubMed Central

Rousset, Francis; Nguyen, Minh Vu Chuong; Grange, Laurent; Morel, Françoise; Lardy, Bernard

2013-01-01

Interleukin-1β (IL-1β) activates the production of reactive oxygen species (ROS) and secretion of MMPs as well as chondrocyte apoptosis. Those events lead to matrix breakdown and are key features of osteoarthritis (OA). We confirmed that in human C-20/A4 chondrocytes the NADPH oxidase Nox4 is the main source of ROS upon IL-1β stimulation. Since heme molecules are essential for the NADPH oxidase maturation and activity, we therefore investigated the consequences of the modulation of Heme oxygenase-1 (HO-1), the limiting enzyme in heme catabolism, on the IL-1β signaling pathway and more specifically on Nox4 activity. Induction of HO-1 expression decreased dramatically Nox4 activity in C-20/A4 and HEK293 T-REx™ Nox4 cell lines. Unexpectedly, this decrease was not accompanied by any change in the expression, the subcellular localization or the maturation of Nox4. In fact, the inhibition of the heme synthesis by succinylacetone rather than heme catabolism by HO-1, led to a confinement of the Nox4/p22phox heterodimer in the endoplasmic reticulum with an absence of redox differential spectrum highlighting an incomplete maturation. Therefore, the downregulation of Nox4 activity by HO-1 induction appeared to be mediated by carbon monoxide (CO) generated from the heme degradation process. Interestingly, either HO-1 or CO caused a significant decrease in the expression of MMP-1 and DNA fragmentation of chondrocytes stimulated by IL-1β. These results all together suggest that a modulation of Nox4 activity via heme oxygenase-1 may represent a promising therapeutic tool in osteoarthritis. PMID:23840483

Holmes

NASA Astrophysics Data System (ADS)

Faverzani, M.; HOLMES Collaboration

2017-09-01

The experiment HOLMES, founded by the European Research Council, will perform a calorimetric measurement of the energy released in the electron capture of 163Ho to directly measure the neutrino mass with a sensitivity of ˜ 1 eV. This approach allows to eliminate the problematics connected to the use of external sources and the systematic uncertainties arising from decays on excited states. Such measurement will be performed with low temperature thermal detectors, where the decay energy is converted into a temperature signal measured by sensitive thermometers. HOLMES, besides of being an important step forward in the direct neutrino mass measurement with a calorimetric approach, will also establish the potential of this approach to extend the sensitivity down to 0.1 eV and lower. The best configuration has been defined with Monte Carlo simulations: HOLMES will collect about 3 × 1013 decays with 1000 detectors characterized by an instrumental energy resolution of the order of the eV and a time resolution of few microseconds. For a measuring time of 3 years, this translates in a total required 163Ho activity of about 300 kBq, equivalent to about 6.5 × 1016 163Ho nuclei, or 18 µg. The HOLMES detectors will have 163Ho implanted into Gold absorber coupled to Transition Edge Sensors, which will be read using microwave multiplexed rf-SQUIDs in combination with a ROACH2 based acquisition system. An extensive R&D activity is in progress in order to maximize the multiplexing factor while preserving the performances of the individual detectors. R&D activities aimed at optimizing the single detector performances, the 163Ho isotope production and embedding are in progress and will converge in a preliminary measurement of an array of 16 detectors planned by the end of 2016. We outline here the HOLMES project with its technical challenges, its status and perspectives.

Thermally Induced Interdiffusion and Precipitation in a Ni/Ni 3 Al System

DOE PAGES

Sun, C.; Martinez, E.; Aguiar, J. A.; ...

2015-05-20

Ordered Ni 3Al intermetallic precipitates constitute the main hardening sources of Ni-based superalloys. Here, we report the interdiffusion and precipitation behavior in a Ni/Ni3Al model system. The deposition of Ni3Al on a pure Ni layer at 500°C generated L12-structured γ' (Ni3Al) precipitates, preferentially at the interface. After annealing at 800°C for 1 h, interdiffusion between Ni and Ni3Al layers occurred, and the γ' precipitates that grew near the parent Ni/Ni 3Al interface are ~2.8 times larger in size than those formed in the matrix. In conclusion, Monte Carlo simulations indicate that vacancies preferentially diffuse along the Ni/Ni 3Al interface, increasingmore » the probability of precipitation.« less

Short communication: Jersey × Holstein crossbreds compared with pure Holsteins for body weight, body condition score, fertility, and survival during the first three lactations.

PubMed

Heins, B J; Hansen, L B; Hazel, A R; Seykora, A J; Johnson, D G; Linn, J G

2012-07-01

Crossbred cows (n=80) resulting from the use of Jersey (JE) semen on their pure Holstein (HO) dams were compared with pure HO cows (n=77) for body weight, body condition score, fertility, and survival during their first 3 lactations. Cows were in 2 research herds of the University of Minnesota and calved from September 2003 to June 2008. The JE × HO crossbred cows had significantly less body weight during the first (-56 kg), second (-67 kg), and third (-82 kg) lactations than pure HO cows. However, JE × HO cows had significantly greater body condition score during the first (2.94 vs. 2.84), second (2.97 vs. 2.84), and third (2.99 vs. 2.87) lactations than pure HO cows. For fertility, JE × HO cows had fewer days to first breeding during the first (-10.6d), second (-8.4d), and third (-12.3d) lactations than pure HO cows. Crossbred cows were not significantly different from pure HO cows for number of services during first lactation; however, JE × HO cows had significantly fewer services (2.2) than pure HO cows (2.7) during the second lactation. Also, JE × HO cows had significantly fewer days open than pure HO cows in the first (-24 d), second (-42 d), and third (-42 d) lactations. For survival, JE × HO cows were not significantly different from pure HO cows for percentage of cows calving a second time; however, a tendency existed for a higher percentage of JE × HO cows (63.8%) than pure HO cows (49.4%) to calve a third time, and a higher percentage of JE × HO cows calved a third time within 28, 34, and 40 mo of first calving than pure HO cows. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

HOLMES: The electron capture decay of [Formula: see text]Ho to measure the electron neutrino mass with sub-eV sensitivity.

PubMed

Alpert, B; Balata, M; Bennett, D; Biasotti, M; Boragno, C; Brofferio, C; Ceriale, V; Corsini, D; Day, P K; De Gerone, M; Dressler, R; Faverzani, M; Ferri, E; Fowler, J; Gatti, F; Giachero, A; Hays-Wehle, J; Heinitz, S; Hilton, G; Köster, U; Lusignoli, M; Maino, M; Mates, J; Nisi, S; Nizzolo, R; Nucciotti, A; Pessina, G; Pizzigoni, G; Puiu, A; Ragazzi, S; Reintsema, C; Gomes, M Ribeiro; Schmidt, D; Schumann, D; Sisti, M; Swetz, D; Terranova, F; Ullom, J

The European Research Council has recently funded HOLMES, a new experiment to directly measure the neutrino mass. HOLMES will perform a calorimetric measurement of the energy released in the decay of [Formula: see text]Ho. The calorimetric measurement eliminates systematic uncertainties arising from the use of external beta sources, as in experiments with beta spectrometers. This measurement was proposed in 1982 by A. De Rujula and M. Lusignoli, but only recently the detector technological progress allowed to design a sensitive experiment. HOLMES will deploy a large array of low temperature microcalorimeters with implanted [Formula: see text]Ho nuclei. The resulting mass sensitivity will be as low as 0.4 eV. HOLMES will be an important step forward in the direct neutrino mass measurement with a calorimetric approach as an alternative to spectrometry. It will also establish the potential of this approach to extend the sensitivity down to 0.1 eV. We outline here the project with its technical challenges and perspectives.

High-power graphene mode-locked Tm/Ho co-doped fiber laser with evanescent field interaction.

PubMed

Li, Xiaohui; Yu, Xuechao; Sun, Zhipei; Yan, Zhiyu; Sun, Biao; Cheng, Yuanbing; Yu, Xia; Zhang, Ying; Wang, Qi Jie

2015-11-16

Mid-infrared ultrafast fiber lasers are valuable for various applications, including chemical and biomedical sensing, material processing and military applications. Here, we report all-fiber high-power graphene mode-locked Tm/Ho co-doped fiber laser at long wavelength with evanescent field interaction. Ultrafast pulses up to 7.8 MHz are generated at a center wavelength of 1879.4 nm, with a pulse width of 4.7 ps. A graphene absorber integrated with a side-polished fiber can increase the damage threshold significantly. Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW. By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously. Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

Observation and modelling of the OH, HO_{2} and RO_{2} radicals at a suburban site of Beijing (Huairou) in winter 2016

NASA Astrophysics Data System (ADS)

Tan, Zhaofeng; Lu, Keding; Ma, Xuefei; Birger, Bohn; Broch, Sebastian; Fuchs, Hendrik; Hofzumahaus, Andreas; Holland, Frank; Li, Xin; Liu, Yuhan; Novelli, Anna; Rohrer, Franz; Shao, Min; Wang, Haichao; Wu, Yusheng; Zeng, Limin; Kiendler-Scharr, Astrid; Wahner, Andreas; Zhang, Yuanhang

2017-04-01

A comprehensive field campaign was carried out in winter 2016 in Huairou, a small town located 60 km northeast of Beijing downtown. Concentrations of OH, HO2and RO2 radicals were measured by a laser induced fluorescence instrument. Radical concentrations were smaller than during summer because of reduced solar radiation. Maximum hourly averaged OH, HO2 and RO2 radical concentrations were (3±2)×106cm-3, (8±6)×107 cm-3 and (7±5)×107 cm-3, respectively. Chemical modulation measurements were applied on a few days showing no significant OH interference for different chemical conditions. HONO and HCHO photolysis were found to be the most important primary source of ROx radicals. OH reactivity, the inverse of the OH radical lifetime, was also measured by a laser-photolysis and laser induced fluorescence instrument. In general, CO and NOx were the dominated OH reactants which contributed more than half of the total OH reactivity. The relative high OH concentrations in polluted episode enabled a fast oxidation of fresh emitted pollutants and the formation of secondary products. The observed radical concentrations were compared with the results from a chemical box model. The model is capable of reproducing radical concentrations in the moderate NOx conditions but has difficulty in both the low and high NOx regimes. The underestimation of RO2 radical concentrations in the high NOx conditions indicate a missing RO2 source.

In Situ TiC-Reinforced Ni-Based Composite Coating Prepared by Flame Spraying Using Sucrose as the Source of Carbon

NASA Astrophysics Data System (ADS)

Wang, Haitao; Zhang, Shouquan; Zhu, Jinglei; Huang, Jihua; Liu, Huiyuan; Zhang, Hua

2009-03-01

A Ni-Ti-C composite powder for Reactive Thermal Spraying is made by heating a mixture of titanium, nickel, and sucrose to carbonize the sucrose, which is used as the source of carbon. The carbon obtained by pyrolysis of sucrose is a reactive constituent as well as the binder in the composite powder. The titanium and nickel particles are bound by the carbon to form granules of the composite powder. This powder feedstock was used to prepare in situ TiC-reinforced Ni-based composite coating by oxyacetylene flame spraying. The TiC-Ni composite coating is made of TiC, Ni, and some Ni3Ti. In the coating, a mass of fine TiC particles is uniformly distributed within the metallic matrix. The microhardness and surface hardness of the coating are, respectively, 1433 HV0.2kg and 62 ± 6 (HR30N). The wear resistance is much better for the TiC-Ni composite coating than for the substrate and Ni60 coating.

Theoretical and modeling studies of the atmospheric chemistry of sulfur oxide and hydroxyl radical systems

NASA Astrophysics Data System (ADS)

El-Zanan, Hazem S.

Models are the tools that integrate our understanding of the atmospheric processes. Box models are utilized frequently and used to simulate the fates and transformation of atmospheric pollutants. The results from models are usually used to produce one integrated system and further help the policy makers to develop control strategies. We have investigated the atmospheric chemistry of the SOx and HOx systems. The results of 15 laboratory experiments that involved the studies of the HO-SO2, reaction have been analyzed. Mixtures of HONO, NO, NO2, H2O, SO2 and CO were photolyzed in synthetic air or in nitrogen containing approximately 50 ppm oxygen. Upon analyzing the data we have found that a very large amount of the observed SO2 oxidation (70.0 +/- 9.1%) can not be explained through the gas phase reaction of HO + SO2 reaction alone. The Regional Atmospheric Chemistry Mechanism, Version 2 (RACM2) was used to investigate additional chemical pathways for the oxidation of SO2. The results indicate that a mechanism(s) involving photochemical heterogeneous reactions could account for the observed additional sulfur dioxide oxidation not accounted for by gas phase oxidation alone. We have also investigated the distribution of the hydroxyl radical in different urban and rural areas. Photolysis of ozone and its reactions with nitrogen oxides and organic compounds, including both anthropogenic and biogenic volatile organic compounds (VOCs), control the mixing ratios of the hydroxyl radical (HO). Measurements of ozone, nitrogen oxides and volatile hydrocarbons from a deciduous forest in July 1999 and six sites located in the San Joaquin Valley obtained during the Central California Ozone Study (CCOS) measured in July 2000 and September 2000 were used to estimate the hydroxyl radical concentrations. Two methods were employed to determine the concentrations: (1) box model simulations and (2) steady state approximation of the species concentrations (Production-Loss Method). The results indicate that the concentrations observed here in this study are comparable with the HO concentrations measured and/or modeled from other studies. HO concentrations produced from ozone, formaldehyde and isoprene were by far the most important sources for HO production but the HO removal processes greatly differs between the urban and rural areas. Hydroxyl radical concentrations vary by location, time of the day, season and meteorological conditions. Comparing the HO concentrations from our study with other studies from different urban, rural and marine environments shows that hydroxyl radical concentrations in the urban areas can be lower than some pristine environments.

Investigation of the β-pinene photooxidation by OH in the atmosphere simulation chamber SAPHIR

NASA Astrophysics Data System (ADS)

Kaminski, Martin; Fuchs, Hendrik; Acir, Ismail-Hakki; Bohn, Birger; Brauers, Theo; Dorn, Hans-Peter; Häseler, Rolf; Hofzumahaus, Andreas; Li, Xin; Lutz, Anna; Nehr, Sascha; Rohrer, Franz; Tillmann, Ralf; Vereecken, Luc; Wegener, Robert; Wahner, Andreas

2017-06-01

Besides isoprene, monoterpenes are the non-methane volatile organic compounds (VOCs) with the highest global emission rates. Due to their high reactivity towards OH, monoterpenes can dominate the radical chemistry of the atmosphere in forested areas. In the present study the photochemical degradation mechanism of β-pinene was investigated in the Jülich atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). One focus of this study is on the OH budget in the degradation process. Therefore, the SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, important OH precursors (O3, HONO, HCHO), the parent VOC β-pinene, its main oxidation products, acetone and nopinone and photolysis frequencies. All experiments were carried out under low-NO conditions ( ≤ 300 ppt) and at atmospheric β-pinene concentrations ( ≤ 5 ppb) with and without addition of ozone. For the investigation of the OH budget, the OH production and destruction rates were calculated from measured quantities. Within the limits of accuracy of the instruments, the OH budget was balanced in all β-pinene oxidation experiments. However, even though the OH budget was closed, simulation results from the Master Chemical Mechanism (MCM) 3.2 showed that the OH production and destruction rates were underestimated by the model. The measured OH and HO2 concentrations were underestimated by up to a factor of 2, whereas the total OH reactivity was slightly overestimated because the model predicted a nopinone mixing ratio which was 3 times higher than measured. A new, theory-derived, first-generation product distribution by Vereecken and Peeters (2012) was able to reproduce the measured nopinone time series and the total OH reactivity. Nevertheless, the measured OH and HO2 concentrations remained underestimated by the numerical simulations. These observations together with the fact that the measured OH budget was closed suggest the existence of unaccounted sources of HO2. Although the mechanism of additional HO2 formation could not be resolved, our model studies suggest that an activated alkoxy radical intermediate proposed in the model of Vereecken and Peeters (2012) generates HO2 in a new pathway, whose importance has been underestimated so far. The proposed reaction path involves unimolecular rearrangement and decomposition reactions and photolysis of dicarbonyl products, yielding additional HO2 and CO. Further experiments and quantum chemical calculations have to be made to completely unravel the pathway of HO2 formation.

Spectroscopy and microchip laser operation of Tm, Ho:KYW crystals with different Ho concentrations

NASA Astrophysics Data System (ADS)

Gusakova, N. V.; Kurilchik, S. V.; Yasukevich, A. S.; Kisel, V. E.; Dashkevich, V. I.; Orlovich, V. A.; Pavlyuk, A. A.; Vatnik, S. M.; Bagaev, S. N.; Kuleshov, N. V.

2018-02-01

The spectroscopic properties of Tm, Ho:KYW crystals with different Ho concentrations were investigated. The diode-pumped microchip laser operation of Tm (5 at.%), Ho (0.5 at.%):KYW and Tm (5 at.%), Ho (1 at.%):KYW was demonstrated. The highest, to our knowledge, output power of 480 mW with slope efficiency of 31% for CW Tm (5 at.%), Ho (0.5 at.%):KYW microchip laser was obtained.

Fragment emission from the mass-symmetric reactions 58Fe,58Ni +58Fe,58Ni at Ebeam=30 MeV/nucleon

NASA Astrophysics Data System (ADS)

Ramakrishnan, E.; Johnston, H.; Gimeno-Nogues, F.; Rowland, D. J.; Laforest, R.; Lui, Y.-W.; Ferro, S.; Vasal, S.; Yennello, S. J.

1998-04-01

The mass-symmetric reactions 58Fe,58Ni +58Fe,58Ni were studied at a beam energy of Ebeam=30 MeV/nucleon in order to investigate the isospin dependence of fragment emission. Ratios of inclusive yields of isotopic fragments from hydrogen through nitrogen were extracted as a function of laboratory angle. A moving source analysis of the data indicates that at laboratory angles around 40° the yield of intermediate mass fragments (IMF's) beyond Z=3 is predominantly from a midrapidity source. The angular dependence of the relative yields of isotopes beyond Z=3 indicates that the IMF's at more central angles originate from a source which is more neutron deficient than the source responsible for fragments emitted at forward angles. The charge distributions and kinetic energy spectra of the IMF's at various laboratory angles were well reproduced by calculations employing a quantum molecular-dynamics code followed by a statistical multifragmentation model for generating fragments. The calculations indicate that the measured IMF's originate mainly from a single source. The isotopic composition of the emitted fragments is, however, not reproduced by the same calculation. The measured isotopic and isobaric ratios indicate an emitting source that is more neutron rich in comparison to the source predicted by model calculations.

AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE

EPA Science Inventory

AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE

Heme oxygenase (HO) occurs in biological tissues as two major isoforms HO-1 and HO-2. HO-1 is inducible by many treatments, particularly oxidative stress-related conditions such as depletion of gl...

Source apportionment of heavy metals in agricultural soil based on PMF: A case study in Hexi Corridor, northwest China.

PubMed

Guan, Qingyu; Wang, Feifei; Xu, Chuanqi; Pan, Ninghui; Lin, Jinkuo; Zhao, Rui; Yang, Yanyan; Luo, Haiping

2018-02-01

Hexi Corridor is the most important base of commodity grain and producing area for cash crops. However, the rapid development of agriculture and industry has inevitably led to heavy metal contamination in the soils. Multivariate statistical analysis, GIS-based geostatistical methods and Positive Matrix Factorization (PMF) receptor modeling techniques were used to understand the levels of heavy metals and their source apportionment for agricultural soil in Hexi Corridor. The results showed that the average concentrations of Cr, Cu, Ni, Pb and Zn were lower than the secondary standard of soil environmental quality; however, the concentrations of eight metals (Cr, Cu, Mn, Ni, Pb, Ti, V and Zn) were higher than background values, and their corresponding enrichment factor values were significantly greater than 1. Different degrees of heavy metal pollution occurred in the agricultural soils; specifically, Ni had the most potential for impacting human health. The results from the multivariate statistical analysis and GIS-based geostatistical methods indicated both natural sources (Co and W) and anthropogenic sources (Cr, Cu, Mn, Ni, Pb, Ti, V and Zn). To better identify pollution sources of heavy metals in the agricultural soils, the PMF model was applied. Further source apportionment revealed that enrichments of Pb and Zn were attributed to traffic sources; Cr and Ni were closely related to industrial activities, including mining, smelting, coal combustion, iron and steel production and metal processing; Zn and Cu originated from agricultural activities; and V, Ti and Mn were derived from oil- and coal-related activities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural tuning of nanogaps using electromigration induced by field emission current with bipolar biasing

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

Yagi, Mamiko; Ito, Mitsuki; Shirakashi, Jun-ichi, E-mail: shrakash@cc.tuat.ac.jp

We report a new method for fabrication of Ni nanogaps based on electromigration induced by a field emission current. This method is called “activation” and is demonstrated here using a current source with alternately reversing polarities. The activation procedure with alternating current bias, in which the current source polarity alternates between positive and negative bias conditions, is performed with planar Ni nanogaps defined on SiO{sub 2}/Si substrates at room temperature. During negative biasing, a Fowler-Nordheim field emission current flows from the source (cathode) to the drain (anode) electrode. The Ni atoms at the tip of the drain electrode are thusmore » activated and then migrate across the gap from the drain to the source electrode. In contrast, in the positive bias case, the field emission current moves the activated atoms from the source to the drain electrode. These two procedures are repeated until the tunnel resistance of the nanogaps is successively reduced from 100 TΩ to 48 kΩ. Scanning electron microscopy and atomic force microscopy studies showed that the gap separation narrowed from approximately 95 nm to less than 10 nm because of the Ni atoms that accumulated at the tips of both the source and drain electrodes. These results show that the alternately biased activation process, which is a newly proposed atom transfer technique, can successfully control the tunnel resistance of the Ni nanogaps and is a suitable method for formation of ultrasmall nanogap structures.« less

Density-functional study of the structures and properties of holmium-doped silicon clusters HoSi n (n = 3-9) and their anions.

PubMed

Hou, Liyuan; Yang, Jucai; Liu, Yuming

2017-04-01

The structures and properties of Ho-doped Si clusters, including their adiabatic electron affinities (AEAs), simulated photoelectron spectra (PESs), stabilities, magnetic moments, and charge-transfer characteristics, were systematically investigated using four density-functional methods. The results show that the double-hybrid functional (which includes an MP2 correlation component) can accurately predict the ground-state structure and properties of Ho-doped Si clusters. The ground-state structures of HoSi n (n = 3-9) are sextuplet electronic states. The structures of these Ho-doped Si clusters (aside from HoSi 7 ) are substitutional. The ground-state structures of HoSi n - are quintuplet electronic states. Their predicted AEAs are in excellent agreement with the experimental ones. The mean absolute error in the theoretical AEAs of HoSi n (n = 4-9) is only 0.04 eV. The simulated PESs for HoSi n - (n = 5-9) are in good agreement with the experimental PESs. Based on its simulated PES and theoretical AEA, we reassigned the experimental PES of HoSi 4 - and obtained an experimental AEA of 2.2 ± 0.1 eV. The dissociation energies of Ho from HoSi n and HoSi n - (n = 3-9) were evaluated to test the relative stabilities of the clusters. HOMO-LUMO gap analysis indicated that doping the Si clusters with the rare-earth metal atom significantly increases their photochemical reactivity. Natural population analysis showed that the magnetic moments of HoSi n (n = 3-9) and their anions derive mainly from the Ho atom. It was also found that the magnetic moments of Ho in the HoSi n clusters are larger than the magnetic moment of an isolated Ho atom.

OH in the Tropical Upper Troposhere and Its Relationships to Solar Radiation and Reactive Nitrogen

NASA Technical Reports Server (NTRS)

Gao, R. S.; Rosenlof, K. H.; Fahey, D. W.; Wennberg, P. O.; Hintsa, E. J.; Hanisco, T. F.

2014-01-01

In situ measurements of [OH], [HO2] (square brackets denote species concentrations), and other chemical species were made in the tropical upper troposphere (TUT). [OH] showed a robust correlation with solar zenith angle. Beyond this dependence, however, [HOx] ([OH] + [HO2]) only weakly responds to variations in its source and sink species. For example, at a given SZA, [HOx] was broadly independent of the product of [O3] and [H2O]. This suggests that [OH] is heavily buffered in the TUT. One important exception to this result is found in regions with very low [O3], [NO], and [NOy], where [OH] is highly suppressed, pointing to the critical role of NO in sustaining OH in the TUT.

Regio- and chemoselective reduction of nitroarenes and carbonyl compounds over recyclable magnetic ferrite-nickel nanoparticles (Fe(3)O(4)-Ni) by using glycerol as a hydrogen source.

PubMed

Gawande, Manoj B; Rathi, Anuj K; Branco, Paula S; Nogueira, Isabel D; Velhinho, Alexandre; Shrikhande, Janhavi J; Indulkar, Utkarsha U; Jayaram, Radha V; Ghumman, C Amjad A; Bundaleski, Nenad; Teodoro, Orlando M N D

2012-10-01

Reduction by magnetic nano-Fe(3)O(4)-Ni: a facile, simple and environmentally friendly hydrogen-transfer reaction that takes place over recyclable ferrite-nickel magnetic nanoparticles (Fe(3)O(4)-Ni) by using glycerol as hydrogen source allows aromatic amines and alcohols to be synthesized from the precursor nitroarenes and carbonyl compounds. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Ni(cod) 2][Al(OR F) 4], a Source for Naked Nickel(I) Chemistry

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

Schwab, Miriam M.; Himmel, Daniel; Kacprzak, Sylwia

The straightforward synthesis of the cationic, purely organometallic Ni I salt [Ni(cod) 2] +[Al(OR F) 4] - was realized through a reaction between [Ni(cod) 2] and Ag[Al(OR F) 4] (cod=1,5-cyclooctadiene). Crystal-structure analysis and EPR, XANES, and cyclic voltammetry studies confirmed the presence of a homoleptic NiI olefin complex. Weak interactions between the metal center, the ligands, and the anion provide a good starting material for further cationic NiI complexes.

Motor coordination in mice with hotfoot, Lurcher, and double mutations of the Grid2 gene encoding the delta-2 excitatory amino acid receptor.

PubMed

Lalonde, R; Hayzoun, K; Selimi, F; Mariani, J; Strazielle, C

2003-11-01

Grid2(ho/ho) is a loss of function gene mutation resulting in abnormal dendritic arborizations of Purkinje cells. These mutants were compared in a series of motor coordination tests requiring balance and equilibrium to nonataxic controls (Grid2(ho/+)) and to a double mutant (Grid2(ho/Lc)) with an inserted Lc mutation. The performance of Grid2(ho/ho) mutant mice was poorer than that of controls on stationary beam, coat hanger, unsteady platform, and rotorod tests. Grid2(ho/Lc) did not differ from Grid2(Lc/+) mice. However, the insertion of the Lc mutation in Grid2(ho/Lc) potentiated the deficits found in Grid2(ho/ho) in stationary beam, unsteady platform, and rotorod tests. These results indicate a deleterious effect of the Lc mutation on Grid2-deficient mice.

Main components of PM10 in an area influenced by a cement plant in Catalonia, Spain: Seasonal and daily variations.

PubMed

Rovira, Joaquim; Sierra, Jordi; Nadal, Martí; Schuhmacher, Marta; Domingo, José L

2018-05-01

Particulate matter (PM) composition has a key role in a wide range of health outcomes, such as asthma, chronic obstructive pulmonary disease, lung cancer, cardiovascular disease, and death, among others. Montcada i Reixac, a municipality located in the Barcelona metropolitan area (Catalonia, Spain), for its location and orography, is an interesting case- study to investigate air pollution. The area is also characterized by the presence of different industrial emission sources, including a cement factory and a large waste management plant, as well as an intense traffic. In this study, PM 10 levels, trace elements, ions, and carbonaceous particles were determined for a long time period (2013-2016) in this highly polluted area. PM 10 samples were collected during six consecutive days in two campaigns (cold and warm) per year. A number of elements (As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, K, La, Li, Hg, Mg, Mn, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sc, Se, Sm, Sn, Sr, Tb, Th, Ti, Tl, U, V, W, Y, Yb, and Zr), ions (Cl - , SO 4 2- , NO 3 - , and NH 4 + ), and carbonaceous content (total carbon, organic plus elemental carbon, and CO 3 2- ), were analysed. These data were used to identify the PM 10 main components: mineral matter, sea spray, secondary inorganic aerosols, organic matter plus elemental carbon, trace elements or indeterminate fraction. Although a clear seasonality (cold vs. warm periods) was found, there were no differences between working days and weekends. Obviously, the cement plant influences the surrounding environment. However, no differences in trace elements related with the cement plant activity (Al, Ca, Ni and V) between weekdays and weekends were noted. However, some traffic-related elements (i.e., Co, Cr, Mn, and Sb) showed significantly higher concentrations in weekdays. Copyright © 2018 Elsevier Inc. All rights reserved.

Determination of hydroxylated polychlorinated biphenyls (HO-PCBs) in blood plasma by high-performance liquid chromatography-electrospray ionization-tandem quadrupole mass spectrometry.

PubMed

Letcher, R J; Li, H X; Chu, S G

2005-01-01

Hydroxylated metabolites of polychlorinated biphenyls (HO-PCBs) and pentachlorophenol (PCP) are halogenated phenolic compounds, and they are increasingly common as environmental contaminants mainly in the blood of wildlife and humans. A methodology based on high-performance liquid chromatography (reversed-phase)-electrospray (negative) ionization-tandem quadrupole mass spectrometry (LC-ESI(-)-MS-MS) in the select ion monitoring or multiple reaction monitoring modes was developed for HO-PCB and PCP determination in blood plasma and serum. Among 11 environmentally relevant HO-PCB congeners and PCP spiked to fetal calf serum, quantitative assessments, including matrix effects on ESI(-) suppression/ enhancement, showed process (recovery) efficiencies of 73% to 89% without internal standard (IS) correction, and 88% to 103% with IS correction, and method limits of quantification ranging from 1 to 50 pg/g (wet weight). Using the developed LC-ESI(-)-MS methodology in comparison with GC-MS and GC-ECD based approaches, similar results were found for HO-PCB identification and quantification in the plasma of polar bear (Ursus maritimus) from the Canadian arctic. LC-ESI(-)-MS identified four HO-PCB congeners [4'-HO-2,2',4,6,6'-pentachlorobiphenyl (4'-HO-CB104), 4-HO-2,3,3',4',5-pentachlorobiphenyl (4-HO-CB107), 4-HO-2,3,3',5,5',6-hexachlorobiphenyl (4-HO-CB165) and 3'-HO-2,2',3,4,4',5,5'-heptachlorobiphenyl (3'-HO-CB180)], and 14 additional tetra- to hepta-chlorinated HO-PCBs isomers in the polar bear plasma.

Apo A1 Mimetic Rescues the Diabetic Phenotype of HO-2 Knockout Mice via an Increase in HO-1 Adiponectin and LKBI Signaling Pathway

PubMed Central

Cao, Jian; Puri, Nitin; Sodhi, Komal; Bellner, Lars; Abraham, Nader G.; Kappas, Attallah

2012-01-01

Insulin resistance, with adipose tissue dysfunction, is one of the hallmarks of metabolic syndrome. We have reported a metabolic syndrome-like phenotype in heme oxygenase (HO)-2 knockout mice, which presented with concurrent HO-1 deficiency and were amenable to rescue by an EET analog. Apo A-I mimetic peptides, such as L-4F, have been shown to induce HO-1 expression and decrease oxidative stress and adiposity. In this study we aimed to characterize alleviatory effects of HO-1 induction (if any) on metabolic imbalance observed in HO-2 KO mice. In this regard, HO-2(−/−) mice were injected with 2 mg/kg/day L-4F, or vehicle, i.p., for 6 weeks. As before, compared to WT animals, the HO-2 null mice were obese, displayed insulin resistance, and had elevated blood pressure. These changes were accompanied by enhanced tissue (hepatic) oxidative stress along with attenuation of HO-1 expression and activity and reduced adiponectin, pAMPK, and LKB1 expression. Treatment with L-4F restored HO-1 expression and activity and increased adiponectin, LKB1, and pAMPK in the HO-2(−/−) mice. These alterations resulted in a decrease in blood pressure, insulin resistance, blood glucose, and adiposity. Taken together, our results show that a deficient HO-1 response, in a state with reduced HO-2 basal levels, is accompanied by disruption of metabolic homeostasis which is successfully restored by an HO-1 inducer. PMID:22577519

Heme oxygenase-1-mediated autophagy protects against pulmonary endothelial cell death and development of emphysema in cadmium-treated mice

PubMed Central

Surolia, Ranu; Karki, Suman; Kim, Hyunki; Yu, Zhihong; Kulkarni, Tejaswini; Mirov, Sergey B.; Carter, A. Brent; Rowe, Steven M.; Matalon, Sadis; Thannickal, Victor J.; Agarwal, Anupam

2015-01-01

Pulmonary exposure to cadmium, a major component of cigarette smoke, has a dramatic impact on lung function and the development of emphysema. Cigarette smoke exposure induces heme oxygenase-1 (HO-1), a cytoprotective enzyme. In this study, we employed a truncated mouse model of emphysema by intratracheal instillation of cadmium (CdCl2) solution (0.025% per 1 mg/kg body wt) in HO-1+/+, HO-1−/−, and overexpressing humanized HO-1 bacterial artificial chromosome (hHO-1BAC) mice. We evaluated the role of HO-1 in cadmium-induced emphysema in mice by analyzing histopathology, micro-computed tomography scans, and lung function tests. CdCl2-exposed HO-1−/− mice exhibited more severe emphysema compared with HO-1+/+ or hHO-1BAC mice. Loss of pulmonary endothelial cells (PECs) from the alveolar capillary membrane is recognized to be a target in emphysema. PECs from HO-1+/+, HO-1−/−, and hHO-1BAC were employed to define the underlying molecular mechanism for the protection from emphysema by HO-1. Electron microscopy, expression of autophagic markers (microtubule-associated protein 1B-light chain 3 II, autophagy protein 5, and Beclin1) and apoptotic marker (cleaved caspase 3) suggested induction of autophagy and apoptosis in PECs after CdCl2 treatment. CdCl2-treated HO-1−/− PECs exhibited downregulation of autophagic markers and significantly increased cleaved caspase 3 expression and activity (∼4-fold higher). Moreover, hHO-1BAC PECs demonstrated upregulated autophagy and absence of cleaved caspase 3 expression or activity. Pretreatment of HO-1+/+ PECs with rapamycin induced autophagy and resulted in reduced cell death upon cadmium treatment. Induction of autophagy following CdCl2 treatment was found to be protective from apoptotic cell death. HO-1 induced protective autophagy in PECs and mitigated cadmium-induced emphysema. PMID:26071551

Heme oxygenase-1-mediated autophagy protects against pulmonary endothelial cell death and development of emphysema in cadmium-treated mice.

PubMed

Surolia, Ranu; Karki, Suman; Kim, Hyunki; Yu, Zhihong; Kulkarni, Tejaswini; Mirov, Sergey B; Carter, A Brent; Rowe, Steven M; Matalon, Sadis; Thannickal, Victor J; Agarwal, Anupam; Antony, Veena B

2015-08-01

Pulmonary exposure to cadmium, a major component of cigarette smoke, has a dramatic impact on lung function and the development of emphysema. Cigarette smoke exposure induces heme oxygenase-1 (HO-1), a cytoprotective enzyme. In this study, we employed a truncated mouse model of emphysema by intratracheal instillation of cadmium (CdCl2) solution (0.025% per 1 mg/kg body wt) in HO-1(+/+), HO-1(-/-), and overexpressing humanized HO-1 bacterial artificial chromosome (hHO-1BAC) mice. We evaluated the role of HO-1 in cadmium-induced emphysema in mice by analyzing histopathology, micro-computed tomography scans, and lung function tests. CdCl2-exposed HO-1(-/-) mice exhibited more severe emphysema compared with HO-1(+/+) or hHO-1BAC mice. Loss of pulmonary endothelial cells (PECs) from the alveolar capillary membrane is recognized to be a target in emphysema. PECs from HO-1(+/+), HO-1(-/-), and hHO-1BAC were employed to define the underlying molecular mechanism for the protection from emphysema by HO-1. Electron microscopy, expression of autophagic markers (microtubule-associated protein 1B-light chain 3 II, autophagy protein 5, and Beclin1) and apoptotic marker (cleaved caspase 3) suggested induction of autophagy and apoptosis in PECs after CdCl2 treatment. CdCl2-treated HO-1(-/-) PECs exhibited downregulation of autophagic markers and significantly increased cleaved caspase 3 expression and activity (∼4-fold higher). Moreover, hHO-1BAC PECs demonstrated upregulated autophagy and absence of cleaved caspase 3 expression or activity. Pretreatment of HO-1(+/+) PECs with rapamycin induced autophagy and resulted in reduced cell death upon cadmium treatment. Induction of autophagy following CdCl2 treatment was found to be protective from apoptotic cell death. HO-1 induced protective autophagy in PECs and mitigated cadmium-induced emphysema. Copyright © 2015 the American Physiological Society.

NEUTRON-POOR NICKEL ISOTOPE ANOMALIES IN METEORITES

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

Steele, Robert C. J.; Coath, Christopher D.; Regelous, Marcel

2012-10-10

We present new, mass-independent, Ni isotope data for a range of bulk chondritic meteorites. The data are reported as {epsilon}{sup 60}Ni{sub 58/61}, {epsilon}{sup 62}Ni{sub 58/61}, and {epsilon}{sup 64}Ni{sub 58/61}, or the parts per ten thousand deviations from a terrestrial reference, the NIST SRM 986 standard, of the {sup 58}Ni/{sup 61}Ni internally normalized {sup 60}Ni/{sup 61}Ni, {sup 62}Ni/{sup 61}Ni, and {sup 64}Ni/{sup 61}Ni ratios. The chondrites show a range of 0.15, 0.29, and 0.84 in {epsilon}{sup 60}Ni{sub 58/61}, {epsilon}{sup 62}Ni{sub 58/61}, and {epsilon}{sup 64}Ni{sub 58/61} relative to a typical sample precision of 0.03, 0.05, and 0.08 (2 s.e.), respectively. The carbonaceousmore » chondrites show the largest positive anomalies, enstatite chondrites have approximately terrestrial ratios, though only EH match Earth's composition within uncertainty, and ordinary chondrites show negative anomalies. The meteorite data show a strong positive correlation between {epsilon}{sup 62}Ni{sub 58/61} and {epsilon}{sup 64}Ni{sub 58/61}, an extrapolation of which is within the error of the average of previous measurements of calcium-, aluminium-rich inclusions. Moreover, the slope of this bulk meteorite array is 3.003 {+-} 0.166 which is within the error of that expected for an anomaly solely on {sup 58}Ni. We also determined to high precision ({approx}10 ppm per AMU) the mass-dependent fractionation of two meteorite samples which span the range of {epsilon}{sup 62}Ni{sub 58/61} and {epsilon}{sup 64}Ni{sub 58/61}. These analyses show that 'absolute' ratios of {sup 58}Ni/{sup 61}Ni vary between these two samples whereas those of {sup 62}Ni/{sup 61}Ni and {sup 64}Ni/{sup 61}Ni do not. Thus, Ni isotopic differences seem most likely explained by variability in the neutron-poor {sup 58}Ni, and not correlated anomalies in the neutron-rich isotopes, {sup 62}Ni and {sup 64}Ni. This contrasts with previous inferences from mass-independent measurements of Ni and other transition elements which invoked variable contributions of a neutron-rich component. We have examined different nucleosynthetic environments to determine the possible source of the anomalous material responsible for the isotopic variations observed in Ni and other transition elements within bulk samples. We find that the Ni isotopic variability of the solar system cannot be explained by mixing with a component of bulk stellar ejecta from either SN II, Wolf-Rayet or, an asymptotic giant branch source and is unlikely to result from bulk mixing of material from an SN Ia. However, variable admixture of material from the Si/S zone of an SN II can create all the characteristics of Ni isotope variations in solar system materials. Moreover, these characteristics can also be provided by an SN II with a range of masses from 15 to 40 M{sub Sun }, showing that input from SN II is a robust source for Ni isotope variations in the solar system. Correlations of Ni isotope anomalies with O, Cr, and Ti isotope ratios and Pb/Yb in bulk meteorites suggest that the heterogeneous distribution of isotopic anomalies in the early solar system likely resulted from nebular sorting of chemically or physically different materials bearing different amounts of isotopes synthesized proximally to the collapse of the protosolar nebula.« less

Isolation of 163Ho from dysprosium target material by HPLC for neutrino mass measurements

DOE PAGES

Mocko, Veronika; Taylor, Wayne  A.; Nortier, Francois M.; ...

2015-04-29

The rare earth isotope 163Ho is of interest for neutrino mass measurements. This report describes the isolation of 163Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, 163Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm –3 α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized bymore » MC-ICP-MS to determine the 163Ho/ 165Ho ratio, 163Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4E5 for Dy. As a result, the isolated Ho fraction contained 24.8 ±1.3 ng of 163Ho corresponding to holmium recovery of 72 ± 3%.« less

Isolation of 163Ho from dysprosium target material by HPLC for neutrino mass measurements

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

Mocko, Veronika; Taylor, Wayne  A.; Nortier, Francois M.

The rare earth isotope 163Ho is of interest for neutrino mass measurements. This report describes the isolation of 163Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, 163Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm –3 α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized bymore » MC-ICP-MS to determine the 163Ho/ 165Ho ratio, 163Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4E5 for Dy. As a result, the isolated Ho fraction contained 24.8 ±1.3 ng of 163Ho corresponding to holmium recovery of 72 ± 3%.« less

Investigation of Ni@CoO core-shell nanoparticle films synthesized by sequential layer deposition

NASA Astrophysics Data System (ADS)

Spadaro, M. C.; Luches, P.; Benedetti, F.; Valeri, S.; Turchini, S.; Bertoni, G.; Ferretti, A. M.; Capetti, E.; Ponti, A.; D'Addato, S.

2017-02-01

Films of Ni@CoO core-shell nanoparticles (NP Ni core size d ≈ 11 nm) have been grown on Si/SiOx and lacey carbon supports, by a sequential layer deposition method: a first layer of CoO was evaporated on the substrate, followed by the deposition of a layer of pre-formed, mass-selected Ni NPs, and finally an overlayer of CoO was added. The Ni NPs were formed by a magnetron gas aggregation source, and mass selected with a quadrupole mass filter. The morphology of the films was investigated with Scanning Electron Microscopy and Scanning Transmission Electron Microscopy. The Ni NP cores have a shape compatible with McKay icosahedron, caused by multitwinning occurring during their growth in the source, and the Ni NP layer shows the typical random paving growth mode. After the deposition of the CoO overlayer, CoO islands are observed, gradually extending and tending to merge with each other, with the formation of shells that enclose the Ni NP cores. In situ X-ray Photoelectron Spectroscopy showed that a few Ni atomic layers localized at the core-shell interface are oxidized, hinting at the possibility of creating an intermediate NiO shell between Ni and CoO, depending on the deposition conditions. Finally, X-ray Magnetic Circular Dichroism at the Ni L2,3 absorption edge showed the presence of magnetization at room temperature even at remanence, revealing the possibility of magnetic stabilization of the NP film.

Adenoviral transfer of the heme oxygenase-1 gene protects striatal astrocytes from heme-mediated oxidative injury.

PubMed

Teng, Zhi-Ping; Chen, Jing; Chau, Lee-Young; Galunic, Nicholas; Regan, Raymond F

2004-11-01

Heme oxygenase-1 (HO-1) is induced in the CNS after hemorrhage, and may have an effect on injury to surrounding tissue. Hemin, the preferred substrate of HO, is a neurotoxin that is present in intracranial hematomas. In a prior study, we observed that HO inhibitors increased the vulnerability of cultured cortical astrocytes to heme-mediated oxidative injury. To investigate the effect of HO more specifically, we used an adenoviral vector encoding the human HO-1 gene to specifically increase HO-1 expression. Incubation with 100 MOI of the HO-1 adenovirus (Adv-HHO-1) for 24 h increased both HO-1 protein and HO activity; a control adenovirus lacking the HO-1 gene had no effect. Using a DNA probe that was specific for human HO-1, 80.5 +/- 7.2% of astrocytes were observed to be infected by in situ hybridization. The cell death produced by 30-60 microM hemin was significantly reduced by pretreatment with 100 MOI Adv-HHO-1, as assessed by LDH release, propidium iodide exclusion, and MTT reduction assay. The threefold increase in cell protein oxidation produced by hemin was also attenuated in cultures pretreated with Adv-HHO-1. These results support the hypothesis that HO-1 protects astrocytes from heme-mediated oxidative injury. Specifically increasing astrocytic HO-1 by gene transfer may have a beneficial effect on hemorrhagic CNS injury.

Characterisation of Anopheles gambiae heme oxygenase and metalloporphyrin feeding suggests a potential role in reproduction.

PubMed

Spencer, Christopher S; Yunta, Cristina; de Lima, Glauber Pacelli Gomes; Hemmings, Kay; Lian, Lu-Yun; Lycett, Gareth; Paine, Mark J I

2018-05-03

The mosquito Anopheles gambiae is the principal vector for malaria in sub-Saharan Africa. The ability of A. gambiae to transmit malaria is strictly related to blood feeding and digestion, which releases nutrients for oogenesis, as well as substantial amounts of highly toxic free heme. Heme degradation by heme oxygenase (HO) is a common protective mechanism, and a gene for HO exists in the An. gambiae genome HO (AgHO), although it has yet to be functionally examined. Here, we have cloned and expressed An. gambiae HO (AgHO) in E. coli. Purified recombinant AgHO bound hemin stoichiometrically to form a hemin-enzyme complex similar to other HOs, with a K D of 3.9 ± 0.6 μM; comparable to mammalian and bacterial HOs, but 7-fold lower than that of Drosophila melanogaster HO. AgHO also degraded hemin to biliverdin and released CO and iron in the presence of NADPH cytochrome P450 oxidoreductase (CPR). Optimal AgHO activity was observed at 27.5 °C and pH 7.5. To investigate effects of AgHO inhibition, adult female A. gambiae were fed heme analogues Sn- and Zn-protoporphyrins (SnPP and ZnPP), known to inhibit HO. These led to a dose dependent decrease in oviposition. Cu-protoporphyrin (CuPP), which does not inhibit HO had no effect. These results demonstrate that AgHO is a catalytically active HO and that it may play a key role in egg production in mosquitoes. It also presents a potential target for the development of compounds aimed at sterilising mosquitoes for vector control. Copyright © 2018 Elsevier Ltd. All rights reserved.

Age-dependent redox status in the brain stem of NO-deficient hypertensive rats.

PubMed

Majzúnová, Miroslava; Pakanová, Zuzana; Kvasnička, Peter; Bališ, Peter; Čačányiová, Soňa; Dovinová, Ima

2017-09-11

The brain stem contains important nuclei that control cardiovascular function via the sympathetic nervous system (SNS), which is strongly influenced by nitric oxide. Its biological activity is also largely determined by oxygen free radicals. Despite many experimental studies, the role of AT1R-NAD(P)H oxidase-superoxide pathway in NO-deficiency is not yet sufficiently clarified. We determined changes in free radical signaling and antioxidant and detoxification response in the brain stem of young and adult Wistar rats during chronic administration of exogenous NO inhibitors. Young (4 weeks) and adult (10 weeks) Wistar rats were treated with 7-nitroindazole (7-NI group, 10 mg/kg/day), a specific nNOS inhibitor, with N G -nitro-L-arginine-methyl ester (L-NAME group, 50 mg/kg/day), a nonspecific NOS inhibitor, and with drinking water (Control group) during 6 weeks. Systolic blood pressure was measured by non-invasive plethysmography. Expression of genes (AT1R, AT2R, p22phox, SOD and NOS isoforms, HO-1, MDR1a, housekeeper GAPDH) was identified by real-time PCR. NOS activity was detected by conversion of [3H]-L-arginine to [3H]-L-citrulline and SOD activity was measured using UV VIS spectroscopy. We observed a blood pressure elevation and decrease in NOS activity only after L-NAME application in both age groups. Gene expression of nNOS (youngs) and eNOS (adults) in the brain stem decreased after both inhibitors. The radical signaling pathway triggered by AT1R and p22phox was elevated in L-NAME adults, but not in young rats. Moreover, L-NAME-induced NOS inhibition increased antioxidant response, as indicated by the observed elevation of mRNA SOD3, HO-1, AT2R and MDR1a in adult rats. 7-NI did not have a significant effect on AT1R-NADPH oxidase-superoxide pathway, yet it affected antioxidant response of mRNA expression of SOD1 and stimulated total activity of SOD in young rats and mRNA expression of AT2R in adult rats. Our results show that chronic NOS inhibition by two different NOS inhibitors has age-dependent effect on radical signaling and antioxidant/detoxificant response in Wistar rats. While 7-NI had neuroprotective effect in the brain stem of young Wistar rats, L-NAME- induced NOS inhibition evoked activation of AT1R-NAD(P)H oxidase pathway in adult Wistar rats. Triggering of the radical pathway was followed by activation of protective compensation mechanism at the gene expression level.

Ho3+-doped AlF3-TeO2-based glass fibers for 2.1 µm laser applications

NASA Astrophysics Data System (ADS)

Wang, S. B.; Jia, Z. X.; Yao, C. F.; Ohishi, Y.; Qin, G. S.; Qin, W. P.

2017-05-01

Ho3+-doped AlF3-TeO2-based glass fibers based on AlF3-BaF2-CaF2-YF3-SrF2-MgF2-TeO2 glasses are fabricated by using a rod-in-tube method. The glass rod including a core and a thick cladding layer is prepared by using a suction method, where the thick cladding layer is used to protect the core from the effect of surface crystallization during the fiber drawing. By inserting the glass rod into a glass tube, the glass fibers with relatively low loss (~2.3 dB m-1 @ 1560 nm) are prepared. By using a 38 cm long Ho3+-doped AlF3-TeO2-based glass fiber as the gain medium and a 1965 nm fiber laser as the pump source, 2065 nm lasing is obtained for a threshold pump power of ~220 mW. With further increasing the pump power to ~325 mW, the unsaturated output power of the 2065 nm laser is about 82 mW and the corresponding slope efficiency is up to 68.8%. The effects of the gain fiber length on the lasing threshold, the slope efficiency, and the operating wavelength are also investigated. Our experimental results show that Ho3+-doped AlF3-TeO2-based glass fibers are promising gain media for 2.1 µm laser applications.

Radical production from photosensitization of imidazoles

NASA Astrophysics Data System (ADS)

Corral Arroyo, P.; Gonzalez, L.; Steimer, S.; Aellig, R.; Volkamer, R. M.; George, C.; Bartels-Rausch, T.; Ammann, M.

2015-12-01

Reactions promoted by light are key in atmospheric chemistry. Some of them occur in the condensed phase of aerosols containing light absorbing organic compounds (George et al., 2015). This work explores the radical reactions initiated by near-UV light in mixtures of citric acid (CA) and imidazole-2-carboxaldehyde (IC) using NO as a probe molecule for HO2, by means of coated wall flow tube experiments. Citric acid may act as H atom or electron donor in condensed phase radical cycles. IC may act as a photosensitizer. The loss of NO was measured by a chemiluminescence detector. The dependence of the NO loss on the NO concentration, the IC/CA ratio in the film, relative humidity, light intensity, oxygen molar fraction were investigated as well as the HONO and NO2 yields. We also added halide salts to investigate the effect of a competing electron donor in the system and the output of halogens to the gas phase. We found a correlation between the loss of NO above the film and the molar ratio of IC/CA and the light intensity. The variation of the NO loss with oxygen corroborates a mechanism, in which the triplet excited state of IC is reduced by citric acid, to a reduced ketyl radical that transfers an electron to molecular oxygen, which in turn leads to production of HO2 radicals. Therefore, the NO loss in the gas phase is related to the production of HO2 radicals. Relative humidity had a strong impact on the HO2 output, which shows a maximum production rate at around 30%. The addition of halide ions (X- = Cl-, Br-, I-) increases the HO2 output at low concentration and decrease it at higher concentration when X2- radical ions likely scavenge HO2. We could preliminarily quantify for the first time the contribution of these processes to the oxidative capacity in the atmosphere and conclude that their role is significant for aerosol aging and potentially a significant source of halogen compounds to the gas phase.

The ZONMET thermodynamic and kinetic model of metal condensation

NASA Astrophysics Data System (ADS)

Petaev, Michail I.; Wood, John A.; Meibom, Anders; Krot, Alexander N.; Keil, Klaus

2003-05-01

The ZONMET model of metal condensation is a FORTRAN computer code that calculates condensation with partial isolation-type equilibrium partitioning of the 19 most abundant elements among 203 gaseous and 488 condensed phases and growth in the nebula of a zoned metal grain by condensation from the nebular gas accompanied by diffusional redistribution of Ni, Co, and Cr. Of five input parameters of the ZONMET model (chemical composition of the system expressed as the dust/gas [ D/ G] ratio, nebular pressure [ Ptot], isolation degree [ξ], cooling rate ( CR), and seed size), only two—the D/ G ratio and the CR of the nebular source region of a zoned Fe,Ni grain—are important in determining the grain radius and Ni, Co, and Cr zoning profiles. We found no evidence for the supercooling during condensation of Fe,Ni metal that is predicted by the homogeneous nucleation theory. The model allows estimates to be made of physicochemical parameters in the CH chondrite nebular source regions. Modeling growth and simultaneous diffusional redistribution of Ni, Co, and Cr in the zoned metal grains of CH chondrites reveals that the condensation zoning profiles were substantially modified by diffusion while the grains were growing in the nebula. This means that previous estimates of the physicochemical conditions in the nebular source regions of CH and CB chondrites, based on measured zoning profiles of Ni, Co, Cr, and platinum group elements in Fe,Ni metal grains, need to be corrected. The two zoned metal grains in the PAT 91456 and NWA 470 CH chondrites studied so far require nebular source regions with different chemical compositions ( D/ G = 1 and D/ G = 4, respectively) and thermal histories characterized by variable cooling rates ( CR = 0.011 + 0.0022 × Δ T K/h and CR = 0.05 + 0.0035 × Δ T K/h, respectively). It appears that the metal grains of the CH chondrites were formed in multiple nebular source regions or in different events within the same source region as the CB chondrite metal grains were formed.

Fertility, survival, and conformation of Montbéliarde × Holstein and Viking Red × Holstein crossbred cows compared with pure Holstein cows during first lactation in 8 commercial dairy herds.

PubMed

Hazel, A R; Heins, B J; Hansen, L B

2017-11-01

Montbéliarde (MO) × Holstein (HO) and Viking Red (VR) × HO crossbred cows were compared with pure HO cows in 8 large, high-performance dairy herds in Minnesota. All cows calved for the first time from December 2010 to April 2014. Fertility and survival traits were calculated from records of insemination, pregnancy diagnosis, calving, and disposal that were recorded via management software. Body condition score and conformation were subjectively scored once during early lactation by trained evaluators. The analysis of survival to 60 d in milk included 536 MO × HO, 560 VR × HO, and 1,033 HO cows during first lactation. Cows analyzed for other fertility, survival, and conformation traits had up to 13% fewer cows available for analysis. The first service conception rate of the crossbred cows (both types combined) increased 7%, as did the conception rate across the first 5 inseminations, compared with the HO cows during first lactation. Furthermore, the combined crossbred cows (2.11 ± 0.05) had fewer times bred than HO cows (2.30 ± 0.05) and 10 fewer d open compared with their HO herdmates. Across the 8 herds, breed groups did not differ for survival to 60 d in milk; however, the superior fertility of the crossbred cows allowed an increased proportion of the combined crossbreds (71 ± 1.5%) to calve a second time within 14 mo compared with the HO cows (63 ± 1.5%). For survival to second calving, the combined crossbred cows had 4% superior survival compared with the HO cows. The MO × HO and VR × HO crossbred cows both had increased body condition score (+0.50 ± 0.02 and +0.25 ± 0.02, respectively) but shorter stature and less body depth than HO cows. The MO × HO cows had less set to the hock and a steeper foot angle than the HO cows, and the VR × HO cows had more set to the hock with a similar foot angle to the HO cows. The combined crossbred cows had less udder clearance from the hock than HO cows, more width between both front and rear teats, and longer teat length than the HO cows; however, the frequency of first-lactation cows culled for udder conformation was uniformly low (<1%) across the breed groups. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Study of negative ion transport phenomena in a plasma source

NASA Astrophysics Data System (ADS)

Riz, D.; Paméla, J.

1996-07-01

NIETZSCHE (Negative Ions Extraction and Transport ZSimulation Code for HydrogEn species) is a negative ion (NI) transport code developed at Cadarache. This code calculates NI trajectories using a 3D Monte-Carlo technique, taking into account the main destruction processes, as well as elastic collisions (H-/H+) and charge exchanges (H-/H0). It determines the extraction probability of a NI created at a given position. According to the simulations, we have seen that in the case of volume production, only NI produced close to the plasma grid (PG) can be extracted. Concerning the surface production, we have studied how NI produced on the PG and accelerated by the plasma sheath backward into the source could be extracted. We demonstrate that elastic collisions and charge exchanges play an important role, which in some conditions dominates the magnetic filter effect, which acts as a magnetic mirror. NI transport in various conditions will be discussed: volume/surface production, high/low plasmas density, tent filter/transverse filter.

Synergism between polyurethane and polydopamine in the synthesis of Ni-Fe alloy monoliths.

PubMed

Naresh Kumar, Thangavel; Sivabalan, Santhana; Chandrasekaran, Naveen; Phani, Kanala Lakshminarasimha

2015-02-04

Herein, we report the first synthesis of a light-weight macroporous 3-D alloy monolith of Ni-Fe/C using synergism between polydopamine (pDA) and polyurethane (pU); in situ formed polyurethane (pU) enables efficient mixing of pDA (carbon source) and Ni-FeOx resulting in Ni-Fe alloy monoliths at a temperature as low as ∼600 °C. The monolithic Ni-Fe/C exhibits enhanced oxygen evolution activity.

The Dy–Ni–Si system as a representative of the rare earth–Ni–Si family: Its isothermal section and new rare-earth nickel silicides

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

Yuan, Fang; Mozharivskyj, Y.; Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru

The Dy–Ni–Si system has been investigated at 1070 K by X-ray and microprobe analysis. The system contains the 12 known compounds DyNi{sub 10}Si{sub 2}, DyNi{sub 5}Si{sub 3}, DyNi{sub 6}Si{sub 6}, DyNi{sub 4}Si, DyNi{sub 2}Si{sub 2}, Dy{sub 2}Ni{sub 3}Si{sub 5}, DyNiSi{sub 3}, Dy{sub 3}Ni{sub 6}Si{sub 2}, DyNiSi{sub 2}, DyNiSi, Dy{sub 3}NiSi{sub 3}, Dy{sub 3}NiSi{sub 2}, and the new compounds Dy{sub 34}Ni{sub 16−27}Si{sub 50−39} (AlB{sub 2}-type), Dy{sub 2}Ni{sub 15.2−14.1}Si{sub 1.8−2.9} (Th{sub 2}Zn{sub 17}-type), ∼Dy{sub 11}Ni{sub 65}Si{sub 24}, ∼Dy{sub 16}Ni{sub 62}Si{sub 22} (unknown structures), DyNi{sub 7}Si{sub 6} (GdNi{sub 7}Si{sub 6}-type), Dy{sub 3}Ni{sub 8}Si (Ce{sub 3}Co{sub 8}Si-type), DyNi{sub 2}Si (YPd{sub 2}Si-type), ∼Dy{sub 40}Ni{sub 47}Si{submore » 13} and ∼Dy{sub 5}Ni{sub 2}Si{sub 3} (unknown structures). Quasi–binary solid solutions were detected at 1070 (870 K) for Dy{sub 2}Ni{sub 17}, DyNi{sub 5}, DyNi{sub 7}, DyNi{sub 3}, DyNi{sub 2}, DyNi, DySi{sub 2} and DySi{sub 1.67}. No detectable solubility is observed for the other binary compounds of the Dy–Ni–Si system. The crystal structures of new phases RNi{sub 7}Si{sub 6} (GdNi{sub 7}Si{sub 6}-type), R{sub 3}Ni{sub 8}Si (Ce{sub 3}Co{sub 8}Si-type), RNi{sub 2}Si (YPd{sub 2}Si-type) and R{sub 3}Ni{sub 12}Si{sub 4} (Gd{sub 3}Ru{sub 4}Al{sub 12}-type), with R=Y, Gd–Tm, has been studied. Magnetic properties of few representative compounds are also reported. - Graphical abstract: The Dy–Ni–Si system has been investigated at 1070 K by X-ray and microprobe analysis. The system contains the 12 known compounds DyNi{sub 10}Si{sub 2}, DyNi{sub 5}Si{sub 3}, DyNi{sub 6}Si{sub 6}, DyNi{sub 4}Si, DyNi{sub 2}Si{sub 2}, Dy{sub 2}Ni{sub 3}Si{sub 5}, DyNiSi{sub 3}, Dy{sub 3}Ni{sub 6}Si{sub 2}, DyNiSi{sub 2}, DyNiSi, Dy{sub 3}NiSi{sub 3}, Dy{sub 3}NiSi{sub 2}, and the new compounds Dy{sub 34}Ni{sub 16−27}Si{sub 50−39}, Dy{sub 2}Ni{sub 15.2−14.1}Si{sub 1.8−2.9}, ∼Dy{sub 11}Ni{sub 65}Si{sub 24}, ∼Dy{sub 16}Ni{sub 62}Si{sub 22}, DyNi{sub 7}Si{sub 6}, Dy{sub 3}Ni{sub 8}Si, DyNi{sub 2}Si, ∼Dy{sub 40}Ni{sub 47}Si{sub 13} and ∼Dy{sub 5}Ni{sub 2}Si{sub 3}. Quasi–binary solid solutions were detected for Dy{sub 2}Ni{sub 17}, DyNi{sub 5}, DyNi{sub 7}, DyNi{sub 3}, DyNi{sub 2}, DyNi, DySi{sub 2} and DySi{sub 1.67}. The crystal structures and magnetic properties of new phases RNi{sub 7}Si{sub 6} (GdNi{sub 7}Si{sub 6}-type), R{sub 3}Ni{sub 8}Si (Ce{sub 3}Co{sub 8}Si-type), RNi{sub 2}Si (YPd{sub 2}Si-type) and R{sub 3}Ni{sub 12}Si{sub 4} (Gd{sub 3}Ru{sub 4}Al{sub 12}-type), with R=Y, Gd–Tm, are also reported. - Highlights: • Dy–Ni–Si isothermal section was obtained at 870 K/1070 K. • Twelve known ternary dysprosium nickel silicides were confirmed in Dy–Ni–Si. • Nine new dysprosium nickel silicides were detected in Dy–Ni–Si. • Seventeen new rare earth nickel silicides were detected in (Y, Gd–Tm)–Ni–Si. • Tb{sub 3}Ni{sub 8}Si, Dy{sub 3}Ni{sub 8}Si, Ho{sub 3}Ni{sub 12}Si{sub 4} and DyNi{sub 2}Si show ferromagnetic-like ordering.« less

Ternary oxide nanostructures and methods of making same

DOEpatents

Wong, Stanislaus S [Stony Brook, NY; Park, Tae-Jin [Port Jefferson, NY

2009-09-08

A single crystalline ternary nanostructure having the formula A.sub.xB.sub.yO.sub.z, wherein x ranges from 0.25 to 24, and y ranges from 1.5 to 40, and wherein A and B are independently selected from the group consisting of Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Ce, Cl, Cm, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Ga, Gd, Ge, Hf, Ho, I, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Tc, Te, Ti, Tl, Tm, U, V, W, Y, Yb, and Zn, wherein the nanostructure is at least 95% free of defects and/or dislocations.

Effect of heme oxygenase-1 transduced bone marrow mesenchymal stem cells on damaged intestinal epithelial cells in vitro.

PubMed

Cao, Yi; Wu, Ben-Juan; Zheng, Wei-Ping; Yin, Ming-Li; Liu, Tao; Song, Hong-Li

2017-07-01

In this study, we explored the effects of mesenchymal stem cells (MSCs) from bone marrow overexpressing heme oxygenase-1 (HO-1) on the damaged human intestinal epithelial barrier in vitro. Rat MSCs were isolated from bone marrow and transduced with rat HO-1 recombinant adenovirus (HO-MSCs) for stable expression of HO-1. Colorectal adenocarinoma 2 (Caco2) cells were treated with tumor necrosis factor-α (TNF-α) to establish a damaged colon epithelial model. Damaged Caco2 were cocultured with MSCs, Ad-MSCs, Ad-HO + MSCs or HO-MSCs. mRNA and protein expression of Zona occludens-1 (ZO-1) and human HO-1 and the release of cytokines were measured. ZO-1 and human HO-1 in Caco2 were significantly decreased after treatment with TNF-α; and this effect was reduced when coculture with MSCs from bone marrow. Expression of ZO-1 was not significantly affected by Caco2 treatment with TNF-α, Ad-HO, and MSCs. In contrast, ZO-1 and human HO-1 increased significantly when the damaged Caco2 was treated with HO-MSCs. HO-MSCs showed the strongest effect on the expression of ZO-1 in colon epithelial cells. Coculture with HO-MSCs showed the most significant effects on reducing the expression of IL-2, IL-6, IFN-γ and increasing the expression of IL-10. HO-MSCs protected the intestinal epithelial barrier, in which endogenous HO-1 was involved. HO-MSCs play an important role in the repair process by reducing the release of inflammatory cytokines and increasing the release of anti-inflammatory factors. These results suggested that HO-MSCs from bone marrow were more effective in repairing the damaged intestinal epithelial barrier, and the effectiveness of MSCs was improved by HO-1 gene transduction, which provides favorable support for the application of stem cell therapy in the intestinal diseases. © 2017 The Authors. Cell Biology International Published by John Wiley & Sons Ltd on behalf of International Federation of Cell Biology.

[In situ diffuse reflectance FTIR spectroscopy study of CO adsorption on Ni2P/mesoporous molecule sieve catalysts].

PubMed

Liu, Qian-qian; Ji, Sheng-fu; Wu, Ping-yi; Hu, Lin-hua; Huang, Xiao-fan; Zhu, Ji-qin; Li, Cheng-yue

2009-05-01

Abstract The supported nickel phosphate precursors were prepared by incipient wetness impregnation using nickel nitrate as nickel source, diammonium hydrogen phosphate as phosphorus source, and MCM-41, MCM-48, SBA-15 and SBA-16 as supports, respectively. Then, the supported Ni2 P catalysts were prepared by temperature-programmed reduction in flowing Hz from their nickel phosphate precursors. The in situ diffuse reflectance FTIR spectroscopy (DRIFTS) analysis with the probe molecule CO was carried out to characterize the surface properties. The results indicated that there were significant differences in the spectral features of the samples. The upsilon(CO) absorbances observed for adsorbed CO on mesoporous molecule sieve was attributed to weak physical adsorption. There are four different kinds of upsilon(CO) absorbances observed for adsorbed CO on Ni2 P/MCM-41 catalyst with the following assignments: (1) the formation of Ni(CO)4 at 2055 cm(-1). (2) CO terminally bonded to cus Ni(delta+) (0

Survival, lifetime production, and profitability of Normande × Holstein, Montbéliarde × Holstein, and Scandinavian Red × Holstein crossbreds versus pure Holsteins.

PubMed

Heins, B J; Hansen, L B; De Vries, A

2012-02-01

Pure Holstein (HO) cows (n=416) were compared with Normande (NO) × HO (n=251), Montbéliarde (MO) × HO (n=503), and Scandinavian Red (SR) × HO (n=321) crossbred cows for survival, lifetime production, and profitability in 6 commercial herds in California. The SR crossbred cows were sired by both Swedish Red and Norwegian Red bulls. Cows calved from June 2002 to January 2009. For analysis of survival to subsequent calvings, lifetime production, and profitability, data were restricted to 3 of 6 herds because they had at least 20 cows in each of the breed groups. All cows had the opportunity to calve at least 4 times. Best prediction, which is used by USDA for national genetic evaluations in the United States, was used to determine lifetime production to 4 yr (1,461 d) in the herd after first calving from test-day observations. Production and survival were estimated after 4 yr to calculate lifetime profit. A profit function was defined to include revenues and expenses for milk, fat, protein, and other solids production; somatic cell count; reproduction; feed intake; calf value; salvage value; dead cow disposal; and fixed cost. The NO × HO (1.2%), MO × HO (2.0%), and SR × HO cows (1.6%) had significantly fewer deaths than did pure HO cows (5.3%) during the first 305 d of first lactation. All crossbred groups had significantly more cows that calved a second, third, and fourth time, and had mean survival that was 300 to 400 d longer than did pure HO cows. The NO × HO, MO × HO, and SR × HO cows had significantly higher lifetime fat plus protein production than did pure HO cows up to 1,461 d after first calving. For profitability (ignoring possible differences in health costs), NO × HO cows had 26% greater projected lifetime profit per cow, but 6.7% less profit per cow-day, than did pure HO cows. On the other hand, MO × HO and SR × HO cows had 50 to 44%, respectively, more projected lifetime profit per cow and 5.3 to 3.6%, respectively, more projected profit per cow-day than did pure HO cows. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Lessons from the decoupling limit of Hořava gravity

NASA Astrophysics Data System (ADS)

Kimpton, Ian; Padilla, Antonio

2010-07-01

We consider the so-called “healthy” extension of Hořava gravity in the limit where the Stuckelberg field decouples from the graviton. We verify the alleged strong coupling problem in this limit, under the assumption that no large dimensionless parameters are put in by hand. This follows from the fact that the dispersion relation for the Stuckelberg field does not have the desired z = 3 anisotropic scaling in the UV. To get the desired scaling and avoid strong coupling one has to introduce a low scale of Lorentz violation and retain some coupling between the graviton and the Stuckelberg field. We also make use of the foliation preserving symmetry to show how the Stuckelberg field couples to some violation of energy conservation. We source the Stuckelberg field using a point particle with a slowly varying mass and show that two such particles feel a constant attractive force. In this particular example, we see no Vainshtein effect, and violations of the Equivalence Principle. The latter is probably generic to other types of source and could potentially be used to place lower bounds on the scale of Lorentz violation.

Heme Oxygenase-1 Promotes Survival of Renal Cancer Cells through Modulation of Apoptosis- and Autophagy-regulating Molecules*

PubMed Central

Banerjee, Pallavi; Basu, Aninda; Wegiel, Barbara; Otterbein, Leo E.; Mizumura, Kenji; Gasser, Martin; Waaga-Gasser, Ana Maria; Choi, Augustine M.; Pal, Soumitro

2012-01-01

The cytoprotective enzyme heme oxygenase-1 (HO-1) is often overexpressed in different types of cancers and promotes cancer progression. We have recently shown that the Ras-Raf-ERK pathway induces HO-1 to promote survival of renal cancer cells. Here, we examined the possible mechanisms underlying HO-1-mediated cell survival. Considering the growing evidence about the significance of apoptosis and autophagy in cancer, we tried to investigate how HO-1 controls these events to regulate survival of cancer cells. Rapamycin (RAPA) and sorafenib, two commonly used drugs for renal cancer treatment, were found to induce HO-1 expression in renal cancer cells Caki-1 and 786-O; and the apoptotic effect of these drugs was markedly enhanced upon HO-1 knockdown. Overexpression of HO-1 protected the cells from RAPA- and sorafenib-induced apoptosis and also averted drug-mediated inhibition of cell proliferation. HO-1 induced the expression of anti-apoptotic Bcl-xL and decreased the expression of autophagic proteins Beclin-1 and LC3B-II; while knockdown of HO-1 down-regulated Bcl-xL and markedly increased LC3B-II. Moreover, HO-1 promoted the association of Beclin-1 with Bcl-xL and Rubicon, a novel negative regulator of autophagy. Drug-induced dissociation of Beclin-1 from Rubicon and the induction of autophagy were also inhibited by HO-1. Together, our data signify that HO-1 is up-regulated in renal cancer cells as a survival strategy against chemotherapeutic drugs and promotes growth of tumor cells by inhibiting both apoptosis and autophagy. Thus, application of chemotherapeutic drugs along with HO-1 inhibitor may elevate therapeutic efficiency by reducing the cytoprotective effects of HO-1 and by simultaneous induction of both apoptosis and autophagy. PMID:22843690

Structure prediction and activity analysis of human heme oxygenase-1 and its mutant.

PubMed

Xia, Zhen-Wei; Zhou, Wen-Pu; Cui, Wen-Jun; Zhang, Xue-Hong; Shen, Qing-Xiang; Li, Yun-Zhu; Yu, Shan-Chang

2004-08-15

To predict wild human heme oxygenase-1 (whHO-1) and hHO-1 His25Ala mutant (delta hHO-1) structures, to clone and express them and analyze their activities. Swiss-PdbViewer and Antheprot 5.0 were used for the prediction of structure diversity and physical-chemical changes between wild and mutant hHO-1. hHO-1 His25Ala mutant cDNA was constructed by site-directed mutagenesis in two plasmids of E. coli DH5alpha. Expression products were purified by ammonium sulphate precipitation and Q-Sepharose Fast Flow column chromatography, and their activities were measured. rHO-1 had the structure of a helical fold with the heme sandwiched between heme-heme oxygenase-1 helices. Bond angle, dihedral angle and chemical bond in the active pocket changed after Ala25 was replaced by His25, but Ala25 was still contacting the surface and the electrostatic potential of the active pocket was negative. The mutated enzyme kept binding activity to heme. Two vectors pBHO-1 and pBHO-1(M) were constructed and expressed. Ammonium sulphate precipitation and column chromatography yielded 3.6-fold and 30-fold higher purities of whHO-1, respectively. The activity of delta hHO-1 was reduced 91.21% after mutation compared with whHO-1. Proximal His25 ligand is crucial for normal hHO-1 catalytic activity. delta hHO-1 is deactivated by mutation but keeps the same binding site as whHO-1. delta hHO-1 might be a potential inhibitor of whHO-1 for preventing neonatal hyperbilirubinemia.

Structure prediction and activity analysis of human heme oxygenase-1 and its mutant

PubMed Central

Xia, Zhen-Wei; Zhou, Wen-Pu; Cui, Wen-Jun; Zhang, Xue-Hong; Shen, Qing-Xiang; Li, Yun-Zhu; Yu, Shan-Chang

2004-01-01

AIM: To predict wild human heme oxygenase-1 (whHO-1) and hHO-1 His25Ala mutant (△hHO-1) structures, to clone and express them and analyze their activities. METHODS: Swiss-PdbViewer and Antheprot 5.0 were used for the prediction of structure diversity and physical-chemical changes between wild and mutant hHO-1. hHO-1 His25Ala mutant cDNA was constructed by site-directed mutagenesis in two plasmids of E. coli DH5α . Expression products were purified by ammonium sulphate precipitation and Q-Sepharose Fast Flow column chromatography, and their activities were measured. RESULTS: rHO-1 had the structure of a helical fold with the heme sandwiched between heme-heme oxygenase-1 helices. Bond angle, dihedral angle and chemical bond in the active pocket changed after Ala25 was replaced by His25, but Ala25 was still contacting the surface and the electrostatic potential of the active pocket was negative. The mutated enzyme kept binding activity to heme. Two vectors pBHO-1 and pBHO-1(M) were constructed and expressed. Ammonium sulphate precipitation and column chromatography yielded 3.6-fold and 30-fold higher purities of whHO-1, respectively. The activity of △hHO-1 was reduced 91.21% after mutation compared with whHO-1. CONCLUSION: Proximal His25 ligand is crucial for normal hHO-1 catalytic activity. △hHO-1 is deactivated by mutation but keeps the same binding site as whHO-1. △hHO-1 might be a potential inhibitor of whHO-1 for preventing neonatal hyperbilirubinemia. PMID:15285018

Enhancement of DEN-induced liver tumorigenesis in heme oxygenase-1 G143H mutant transgenic mice

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

Jin, Jianfeng; Wang, Dayong; Xiao, Haifeng

Heme oxygenase (HO) is the rate-limiting enzyme in heme metabolism. HO-1 exhibits anti-oxidative and anti-inflammatory function via the actions of its metabolite, respectively. A growing body of evidence demonstrates that HO-1 is implicated in the pathogenesis and progression of several types of cancer. However, whether HO-1 takes part in healthy-premalignant-malignant transformation is still undefined. In this study, we took advantage of transgenic mice which over-expressed HO-1 dominant negative mutant (HO-1 G143H) and observed its susceptibility to DEN-induced hepatocarcinogenesis. Our results indicate that HO-1 G143H mutant accelerates the progression of tumorigenesis and tumor growth. The mechanism is closely related to enhancementmore » of ROS production which induce more hepatocytes death and secretion of inflammatory cytokines, proliferation of surviving hepatocytes. Our result provides the direct evidence that HO-1 plays an important protective role in liver carcinogenesis. Alternatively, we suggest the possible explanation on effect of HO-1 promoter polymorphism which involved in tumorigenesis. - Highlights: • Enhancement of DEN-induced hepatocarcinogenesis in HO-1 G143H Tg mice. • HO-1G143H mutant enhanced DEN-induced ROS production and liver injury. • HO-1G143H mutant aggravated DEN-induced changes of inflammatory factors and cell proliferation.« less

Silencing heme oxygenase-1 gene expression in retinal pigment epithelial cells inhibits proliferation, migration and tube formation of cocultured endothelial cells

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

Zhang, Wenjie; Zhang, Xiaomei, E-mail: zhangxm667@163.com; Lu, Hong

2013-05-10

Highlights: •HO-1 is highly induced in RPE cells by hypoxia. •Inhibition of HO-1 activity and knockdown of HO-1 expression inhibit VEGF expression in RPE cells under hypoxia. •Knockdown of HO-1 in RPE cells inhibits angiogenesis of endothelial cells in vitro. -- Abstract: Heme oxygenase-1 (HO-1) plays an important role in the vasculature and in the angiogenesis of tumors, wounds and other environments. Retinal pigment epithelial (RPE) cells and choroidal endothelial cells (CECs) are the main cells involved in choroidal neovascularization (CNV), a process in which hypoxia plays an important role. Our aim was to evaluate the role of human RPE-cellmore » HO-1 in the angiogenic activities of cocultured endothelial cells under hypoxia. Small interfering RNA (siRNA) for HO-1 was transfected into human RPE cell line ARPE-19, and zinc protoporphyrin (ZnPP) was used to inhibit HO-1 activity. Knockdown of HO-1 expression and inhibition of HO-1 activity resulted in potent reduction of the expression of vascular endothelial growth factor (VEGF) under hypoxia. Furthermore, knockdown of HO-1 suppressed the proliferation, migration and tube formation of cocultured endothelial cells. These findings indicated that HO-1 might have an angiogenic effect in CNV through modulation of VEGF expression and might be a potential target for treating CNV.« less

AN ELISA ASSAY FOR HEME OXYGENASE (HO-1)

EPA Science Inventory

An ELISA assay for heme oxygenase (HO-l )

Abstract

A double antibody capture ELISA for the HO-l protein has been developed to separately quantitate HO-I protein. The use of 2.5% NP40 detergent greatly assists in freeing HO-l protein from membranes and/or other cel...

Betavoltaic effect in titanium dioxide nanotube arrays under build-in potential difference

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Chen, Ranbin; San, Haisheng; Liu, Guohua; Wang, Kaiying

2015-05-01

We report the fabrication of sandwich-type metal/TiO2 nanotube (TNT) array/metal structures as well as their betavoltaic effects under build-in voltage through contact potential difference. The sandwiched structure is integrated by immobilized TNT arrays on Ti foil with radioisotope 63Ni planar source on Ni substrate (Ni-63Ni/TNT array/Ti). Under irradiation of the 63Ni source with activity of 8 mCi, the structure (TNT diameter ∼ 130 nm, length ∼ 11 μm) presents optimum energy conversion efficiency of 7.30% with open-circuit voltage of 1.54 V and short-circuit current of 12.43 nA. The TNT arrays exhibit a highly potential for developing betavoltaic batteries due to its wide band gap and nanotube array configuration. The TNT-betavoltaic concept offers a facile solution for micro/nano electronics with high efficiency and long life-time instead of conventional planar junction-type batteries.

Production, Quality Control and Biological Evaluation of 166Ho-PDTMP as a Possible Bone Palliation Agent

PubMed Central

Zolghadri, Samaneh; Jalilian, Amir Reza; Naseri, Zohreh; Yousefnia, Hassan; Bahrami-Samani, Ali; Ghannadi-Maragheh, Mohammad; Afarideh, Hossein

2013-01-01

Objective(s): In this study, 166Ho-1,2-propylene di-amino tetra(methy1enephosphonicAcid) (166Ho-PDTMP) complex was prepared as a bone palliation agent. Materials and Methods: The complex was successfully prepared using an in-house synthesized EDTMP ligand and 166HoCl3. Ho-166 chloride was obtained by thermal neutron irradiation (1 × 1013 n.cm-2.s-1) of natural Ho(NO3)3 samples followed by radiolabeling and stability studies. Biodistribution in wild type rats was also peformed. Results: The complex was prepared with the specific activity of 278 GBq/mg and high radiochemical purity (>99%, checked by ITLC). 166Ho-PDTMP complex was stabilized in the final preparation and in the presence of human serum (>90%) up to 72 hr. The biodistribution of 166Ho-PDTMP in wild-type rats demonstrated significant bone uptake was up to 48 hr compared to 166HoCl3. Conclusion: The produced 166Ho-PDTMP properties suggest a possible new bone palliative therapeutic to overcome the metastatic bone pains. PMID:23826495

Curcumin-induced heme oxygenase-1 expression prevents H2O2-induced cell death in wild type and heme oxygenase-2 knockout adipose-derived mesenchymal stem cells.

PubMed

Cremers, Niels A J; Lundvig, Ditte M S; van Dalen, Stephanie C M; Schelbergen, Rik F; van Lent, Peter L E M; Szarek, Walter A; Regan, Raymond F; Carels, Carine E; Wagener, Frank A D T G

2014-10-08

Mesenchymal stem cell (MSC) administration is a promising adjuvant therapy to treat tissue injury. However, MSC survival after administration is often hampered by oxidative stress at the site of injury. Heme oxygenase (HO) generates the cytoprotective effector molecules biliverdin/bilirubin, carbon monoxide (CO) and iron/ferritin by breaking down heme. Since HO-activity mediates anti-apoptotic, anti-inflammatory, and anti-oxidative effects, we hypothesized that modulation of the HO-system affects MSC survival. Adipose-derived MSCs (ASCs) from wild type (WT) and HO-2 knockout (KO) mice were isolated and characterized with respect to ASC marker expression. In order to analyze potential modulatory effects of the HO-system on ASC survival, WT and HO-2 KO ASCs were pre-treated with HO-activity modulators, or downstream effector molecules biliverdin, bilirubin, and CO before co-exposure of ASCs to a toxic dose of H2O2. Surprisingly, sensitivity to H2O2-mediated cell death was similar in WT and HO-2 KO ASCs. However, pre-induction of HO-1 expression using curcumin increased ASC survival after H2O2 exposure in both WT and HO-2 KO ASCs. Simultaneous inhibition of HO-activity resulted in loss of curcumin-mediated protection. Co-treatment with glutathione precursor N-Acetylcysteine promoted ASC survival. However, co-incubation with HO-effector molecules bilirubin and biliverdin did not rescue from H2O2-mediated cell death, whereas co-exposure to CO-releasing molecules-2 (CORM-2) significantly increased cell survival, independently from HO-2 expression. Summarizing, our results show that curcumin protects via an HO-1 dependent mechanism against H2O2-mediated apoptosis, and likely through the generation of CO. HO-1 pre-induction or administration of CORMs may thus form an attractive strategy to improve MSC therapy.

High-power graphene mode-locked Tm/Ho co-doped fiber laser with evanescent field interaction

PubMed Central

Li, Xiaohui; Yu, Xuechao; Sun, Zhipei; Yan, Zhiyu; Sun, Biao; Cheng, Yuanbing; Yu, Xia; Zhang, Ying; Wang, Qi Jie

2015-01-01

Mid-infrared ultrafast fiber lasers are valuable for various applications, including chemical and biomedical sensing, material processing and military applications. Here, we report all-fiber high-power graphene mode-locked Tm/Ho co-doped fiber laser at long wavelength with evanescent field interaction. Ultrafast pulses up to 7.8 MHz are generated at a center wavelength of 1879.4 nm, with a pulse width of 4.7 ps. A graphene absorber integrated with a side-polished fiber can increase the damage threshold significantly. Harmonics mode-locking can be obtained till to the 21th harmonics at a pump power of above 500 mW. By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously. Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies. PMID:26567536

A transportable system for the in situ recording of color Denisyuk holograms of Greek cultural heritage artifacts in silver halide panchromatic emulsions and an optimized illuminating device for the finished holograms

NASA Astrophysics Data System (ADS)

Sarakinos, A.; Lembessis, A.; Zervos, N.

2013-02-01

In this paper we will present the Z-Lab transportable color holography system, the HoLoFoS illuminator and results of actual in situ recording of color Denisyuk holograms of artifacts on panchromatic silver halide emulsions. Z-lab and HoLoFoS were developed to meet identified prerequisites of holographic recording of artifacts: a) in situ recording b) a high degree of detail and color reproduction c) a low degree of image distortions. The Z-Lab consists of the Z3RGB camera, its accessories and a mobile darkroom. HoLoFoS is an RGB LED-based lighting device for the display of color holograms. The device is capable of digitally controlled intensity mixing and provides a beam of uniform color cross section. The small footprint and emission characteristics of the device LEDs result in a narrow band, quasi point source at selected wavelengths. A case study in recording and displaying 'Optical Clones' of Greek cultural heritage artifacts with the aforementioned systems will also be presented.

Heme oxygenase-1 accelerates tumor angiogenesis of human pancreatic cancer.

PubMed

Sunamura, Makoto; Duda, Dan G; Ghattas, Maivel H; Lozonschi, Lucian; Motoi, Fuyuhiko; Yamauchi, Jun-Ichiro; Matsuno, Seiki; Shibahara, Shigeki; Abraham, Nader G

2003-01-01

Angiogenesis is necessary for the continued growth of solid tumors, invasion and metastasis. Several studies clearly showed that heme oxygenase-1 (HO-1) plays an important role in angiogenesis. In this study, we used the vital microscope system, transparent skinfold model, lung colonization model and transduced pancreatic cancer cell line (Panc-1)/human heme oxygenase-1 (hHO-1) cells, to precisely analyze, for the first time, the effect of hHO-1 gene on tumor growth, angiogenesis and metastasis. Our results revealed that HO-1 stimulates angiogenesis of pancreatic carcinoma in severe combined immune deficient mice. Overexpression of human hHO-1 after its retroviral transfer into Panc-1 cells did not interfere with tumor growth in vitro. While in vivo the development of tumors was accelerated upon transfection with hHO-1. On the other hand, inhibition of heme oxygenase (HO) activity by stannous mesoporphyrin was able transiently to delay tumor growth in a dose dependent manner. Tumor angiogenesis was markedly increased in Panc-1/hHO-1 compared to mock transfected and wild type. Lectin staining and Ki-67 proliferation index confirmed these results. In addition hHO-1 stimulated in vitro tumor angiogenesis and increased endothelial cell survival. In a lung colonization model, overexpression of hHO-1 increased the occurrence of metastasis, while inhibition of HO activity by stannous mesoporphyrin completely inhibited the occurrence of metastasis. In conclusion, overexpression of HO-1 genes potentiates pancreatic cancer aggressiveness, by increasing tumor growth, angiogenesis and metastasis and that the inhibition of the HO system may be of useful benefit for the future treatment of the disease.

Measurement of HO2 chemical kinetics with a new detection method

NASA Technical Reports Server (NTRS)

Lee, Long C.; Suto, Masako

1986-01-01

Reaction rate constants of HO2+O3 were measured at various temperatures using a newly developed HO2 detection method. HO2 was detected by the OH(A-X) emission produced from photodissociative excitation of HO2 at 147 nm. In order to examine the possible interference of other emitting species with the HO2 detection, the photoexcitation processes of all the chemical species existing in the discharge flow tube were also investigated. The results are summarized.

Missing Peroxy Radical Sources within a Summertime Ponderosa Pine Forest

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

Wolfe, G. M.; Cantrell, Chris; Kim, S.

2014-05-13

Organic peroxy (RO2) and hydroperoxy (HO2) radicals are key intermediates in the photochemical processes that generate ozone, secondary organic aerosol and reactive nitrogen reservoirs throughout the troposphere. In regions with ample biogenic hydrocarbons, the richness and complexity of peroxy radical chemistry presents a significant challenge to current-generation models, especially given the scarcity of measurements in such environments. We present peroxy radical observations acquired within a Ponderosa pine forest during the summer 2010 Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen – Rocky Mountain Organic Carbon Study (BEACHON-ROCS). Total peroxy radical mixing ratios reach as high as 180 pptvmore » and are among the highest yet recorded. Using the comprehensive measurement suite to constrain a near-explicit 0-D box model, we investigate the sources, sinks and distribution of peroxy radicals below the forest canopy. The base chemical mechanism underestimates total peroxy radicals by as much as a factor of 3. Peroxy radical sinks are unlikely to be overestimated, suggesting missing sources. A close comparison of model results with observations reveals at least two distinct source signatures. The first missing source, characterized by a sharp midday maximum and a strong dependence on solar radiation, is consistent with photolytic production of HO2. The diel profile of the second missing source peaks in the afternoon and suggests a process that generates RO2 independently of sun-driven photochemistry, such as ozonolysis of reactive hydrocarbons. The maximum magnitudes of these missing sources (~120 and 50 pptv min-1, respectively) are consistent with previous observations alluding to unexpectedly intense oxidation within the forest, and we conclude that a similar mechanism may underlie many such anomalous findings.« less

Skin Barrier Restoration and Moisturization Using Horse Oil-Loaded Dissolving Microneedle Patches.

PubMed

Lee, Chisong; Eom, Younghyon Andrew; Yang, Huisuk; Jang, Mingyu; Jung, Sang Uk; Park, Ye Oak; Lee, Si Eun; Jung, Hyungil

2018-01-01

Horse oil (HO) has skin barrier restoration and skin-moisturizing effects. Although cream formulations have been used widely and safely, their limited penetration through the stratum corneum is a major obstacle to maximizing the cosmetic efficacy of HO. Therefore, we aimed to encapsulate HO in a cosmetic dissolving microneedle (DMN) for efficient transdermal delivery. To overcome these limitations of skin permeation, HO-loaded DMN (HO-DMN) patches were developed and evaluated for their efficacy and safety using in vitro and clinical studies. Despite the lipophilic nature of HO, the HO-DMN patches had a sharp shape and uniform array, with an average length and tip diameter of 388.36 ± 16.73 and 38.54 ± 5.29 µm, respectively. The mechanical strength of the HO-DMN patches was sufficient (fracture force of 0.29 ± 0.01 N), and they could successfully penetrate pig skin. During the 4-week clinical evaluation, HO-DMN patches caused significant improvements in skin and dermal density, skin elasticity, and moisturization. Additionally, a brief safety assessment showed that the HO-DMN patches induced negligible adverse events. The HO-DMNs are efficient, safe, and convenient for wide use in cosmetic applications for skin barrier restoration and moisturization. © 2018 S. Karger AG, Basel.

Characterization of a Ho:Tm:Cr:YAG laser with a Cr:GSAG laser as pumping source

NASA Technical Reports Server (NTRS)

Henderson, George W.

1989-01-01

Rare earth lasers were in existance since the first laser was developed. The primary lasing elements for the class of lasers in the infrared was neodymium and chromium. However, the need for eye safe lasers in the mid-infrared range has prompted an enormous amount of research to the use of other elements. Holmium was investigated extensively as the source of infrared radiation for atmospheric research as well as medical research. The results and procedure are briefly discussed.

Paracrine action of HO-1-modified mesenchymal stem cells mediates cardiac protection and functional improvement.

PubMed

Zeng, Bin; Ren, Xiaofeng; Lin, Guosheng; Zhu, Chengang; Chen, Honglei; Yin, Jiechao; Jiang, Hong; Yang, Bo; Ding, Danhua

2008-10-01

The aim has been to determine whether the supernatants of mesenchymal stem cells (MSCs) transfected with adenovirus carrying human heme oxygenase-1 (hHO-1) gene protect cardiomyocytes from ischemic injury. We have found that hHO-1 infected MSCs (hHO-1-MSCs) increased expression of hHO-1 protein. Apoptosis of cultured hHO-1-MSCs exposed to hypoxia was suppressed. Several cytokines, including HGF, bFGF, TGF-beta, VEGF and IL-1beta, were produced by hHO-1-MSCs, some being significantly enhanced under hypoxia stimulation. Meanwhile, those cytokines reduced caspase-3 level and activity in cultured adult rat ventricular cardiomyocytes (ARVCs) exposed to hypoxia. Supernatants obtained from hHO-1-MSCs improved left ventricular function, limited myocardial infarct size, increased microvessel density, and inhibited apoptosis of cardiomyocytes in rat myocardial infarction. It can be concluded hHO-1-modified MSCs prevent myocardial cell injury via secretion of paracrine-acting mediators.

The reactions of HO2 with CO and NO and the reaction of O(1D) with H2O

NASA Technical Reports Server (NTRS)

Simonaitis, R.; Heicklen, J.

1973-01-01

HO2 radicals were generated by the photolysis of N2O at 2139 A in the presence of excess H2O or H2 and smaller amounts of CO and O2. The O(1D) atoms produced from the photolysis of N2O to give HO radicals or H2 to give HO + H. With H2O two HO radicals are produced for each O(1D) removed low pressures (i.e. approximately 20 torr H2O), but the HO yield drops as the pressure is raised. This drop is attributed to the insertion reaction: O(1D) + H2O + M yields H2O2 +M. The HO radicals generated can react with either CO or H2 to produce H atoms which then add to O2 to produce HO2. Two reactions are given for the reactions of the HO radicals, in the absence of NO.

Summertime photochemistry during CAREBeijing-2007: ROx budgets and O3 formation

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

Liu, Zhen; Wang, Y.; Gu, Dasa

2012-08-28

We analyze summertime photochemistry near the surface in Beijing, China, using a 1-D photochemical model (Regional chEmical and trAnsport Model, REAM-1D) constrained by in situ observations, focusing on the budgets of ROx (OH + HO2 + RO2) radicals and O3 formation. While the modeling analysis focuses on near-surface photochemical budgets, the implications for the budget of O3 in the planetary boundary layer are also discussed. In terms of daytime average, the total ROx primary production rate near the surface in Beijing is 6.6 ppbv per hour (ppbv h{sup 1}, among the highest found in urban atmospheres. The largest primary ROxmore » source in Beijing is photolysis of oxygenated volatile organic compounds (OVOCs), which produces HO2 and RO2 at 2.5 ppbv h{sup 1}1 and 1.7 ppbv h{sup 1}, respectively. Photolysis of excess HONO from an unknown heterogeneous source is the predominant primary OH source at 2.2 ppbv h{sup 1}, much larger than that of O1D+H2O (0.4 ppbv h{sup 1}). The largest ROx sink is via OH + NO2 reaction (1.6 ppbv h{sup 1}), followed by formation of RO2NO2 (1.0 ppbv h{sup 1}) and RONO2 (0.7 ppbv h{sup 1}). Due to the large aerosol surface area, aerosol uptake of HO2 appears to be another important radical sink, although the estimate of its magnitude is highly variable depending on the uptake coefficient value used. The daytime average O3 production and loss rates near the surface are 32 ppbv h{sup 1} and 6.2 ppbv h{sup 1}, respectively. Assuming NO2 to be the source of excess HONO, the NO2 to HONO transformation leads to considerable O3 loss and reduction of its lifetime. Our observation-constrained modeling analysis suggests that oxidation of VOCs (especially aromatics) and heterogeneous reactions (e.g. HONO formation and aerosol uptake HO2) play potentially critical roles in the primary radical budget and O3 formation in Beijing. One important ramification is that O3 production is neither NOx nor VOC limited, but in a transition regime where reduction of either NOx or VOCs could result in reduction of O3 production. The transition regime implies more flexibility in the O3 control strategies than a binary system of either NOx or VOC limited regime. The co-benefit of concurrent reduction of both NOx and VOCs in reducing column O3 production integrated in the planetary boundary layer is significant. Further research on the spatial extent of the transition regime over the polluted eastern China is critically important for controlling regional O3 pollution.« less

Oral delivery of Lactococcus lactis that secretes bioactive heme oxygenase-1 alleviates development of acute colitis in mice.

PubMed

Shigemori, Suguru; Watanabe, Takafumi; Kudoh, Kai; Ihara, Masaki; Nigar, Shireen; Yamamoto, Yoshinari; Suda, Yoshihito; Sato, Takashi; Kitazawa, Haruki; Shimosato, Takeshi

2015-11-25

Mucosal delivery of therapeutic proteins using genetically modified strains of lactic acid bacteria (gmLAB) is being investigated as a new therapeutic strategy. We developed a strain of gmLAB, Lactococcus lactis NZ9000 (NZ-HO), which secretes the anti-inflammatory molecule recombinant mouse heme oxygenase-1 (rmHO-1). The effects of short-term continuous oral dosing with NZ-HO were evaluated in mice with dextran sulfate sodium (DSS)-induced acute colitis as a model of inflammatory bowel diseases (IBD). We identified the secretion of rmHO-1 by NZ-HO. rmHO-1 was biologically active as determined with spectroscopy. Viable NZ-HO was directly delivered to the colon via oral administration, and rmHO-1 was secreted onto the colonic mucosa in mice. Acute colitis in mice was induced by free drinking of 3 % DSS in water and was accompanied by an increase in the disease activity index score and histopathological changes. Daily oral administration of NZ-HO significantly improved these colitis-associated symptoms. In addition, NZ-HO significantly increased production of the anti-inflammatory cytokine interleukin (IL)-10 and decreased the expression of pro-inflammatory cytokines such as IL-1α and IL-6 in the colon compared to a vector control strain. Oral administration of NZ-HO alleviates DSS-induced acute colitis in mice. Our results suggest that NZ-HO may be a useful mucosal therapeutic agent for treating IBD.

Mechanical properties, in vitro corrosion and biocompatibility of newly developed biodegradable Mg-Zr-Sr-Ho alloys for biomedical applications

PubMed Central

Ding, Yunfei; Lin, Jixing; Wen, Cuie; Zhang, Dongmei; Li, Yuncang

2016-01-01

Our previous studies have demonstrated that Mg-Zr-Sr alloys can be anticipated as excellent biodegradable implant materials for load-bearing applications. In general, rare earth elements (REEs) are widely used in magnesium (Mg) alloys with the aim of enhancing the mechanical properties of Mg-based alloys. In this study, the REE holmium (Ho) was added to an Mg-1Zr-2Sr alloy at different concentrations of Mg1Zr2SrxHo alloys (x = 0, 1, 3, 5 wt. %) and the microstructure, mechanical properties, degradation behaviour and biocompatibility of the alloys were systematically investigated. The results indicate that the addition of Ho to Mg1Zr2Sr led to the formation of the intermetallic phases MgHo3, Mg2Ho and Mg17Sr2 which resulted in enhanced mechanical strength and decreased degradation rates of the Mg-Zr-Sr-Ho alloys. Furthermore, Ho addition (≤5 wt. %) to Mg-Zr-Sr alloys led to enhancement of cell adhesion and proliferation of osteoblast cells on the Mg-Zr-Sr-Ho alloys. The in vitro biodegradation and the biocompatibility of the Mg-Zr-Sr-Ho alloys were both influenced by the Ho concentration in the Mg alloys; Mg1Zr2Sr3Ho exhibited lower degradation rates than Mg1Zr2Sr and displayed the best biocompatibility compared with the other alloys. PMID:27553403

Reduction of bilirubin by targeting human heme oxygenase-1 through siRNA.

PubMed

Xia, Zhen-Wei; Li, Chun-E; Jin, You-Xin; Shi, Yi; Xu, Li-Qing; Zhong, Wen-Wei; Li, Yun-Zhu; Yu, Shan-Chang; Zhang, Zi-Li

2007-04-01

Neonatal hyperbilirubinemia is a common clinical condition caused mainly by the increased production and decreased excretion of bilirubin. Current treatment is aimed at reducing the serum levels of bilirubin. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that generates bilirubin. In this study we intended to suppress HO-1 using the RNA interference technique. Small interfering RNA (siRNA)-A, -B, and -C were designed based on human HO-1 (hHO-1) mRNA sequences. siRNA was transfected into a human hepatic cell line (HL-7702). hHO-1 transcription and protein levels were then determined. In addition, the inhibitory effect of siRNA on hHO-1 was assessed in cells treated with hemin or transfected with an hHO-1 plasmid. siRNA-C showed the most potent suppressive effect on hHO-1. This inhibition is dose and time dependent. Compared with control, both hemin and hHO-1 plasmids up-regulated hHO-1 expression in HL-7702 cells. However, the up-regulation was significantly attenuated by siRNA-C. Furthermore, the decrease in hHO-1 activity was coincident with the suppression of its transcription. Finally, siRNA-C was shown to reduce hHO-1 enzymatic activity and bilirubin levels. Thus, this study provides a novel therapeutic rationale by blocking bilirubin formation via siRNA for preventing and treating neonatal hyperbilirubinemia and bilirubin encephalopathy at an early clinical stage.

Sequential interaction of chloride and proton ions with the fast gate steer the voltage-dependent gating in ClC-2 chloride channels

PubMed Central

Sánchez-Rodríguez, Jorge E; De Santiago-Castillo, José A; Contreras-Vite, Juan Antonio; Nieto-Delgado, Pablo G; Castro-Chong, Alejandra; Arreola, Jorge

2012-01-01

The interaction of either H+ or Cl− ions with the fast gate is the major source of voltage (Vm) dependence in ClC Cl− channels. However, the mechanism by which these ions confer Vm dependence to the ClC-2 Cl− channel remains unclear. By determining the Vm dependence of normalized conductance (Gnorm(Vm)), an index of open probability, ClC-2 gating was studied at different [H+]i, [H+]o and [Cl−]i. Changing [H+]i by five orders of magnitude whilst [Cl−]i/[Cl−]o = 140/140 or 10/140 mm slightly shifted Gnorm(Vm) to negative Vm without altering the onset kinetics; however, channel closing was slower at acidic pHi. A similar change in [H+]o with [Cl−]i/[Cl−]o = 140/140 mm enhanced Gnorm in a bell-shaped manner and shifted Gnorm(Vm) curves to positive Vm. Importantly, Gnorm was >0 with [H+]o = 10−10 m but channel closing was slower when [H+]o or [Cl−]i increased implying that ClC-2 was opened without protonation and that external H+ and/or internal Cl− ions stabilized the open conformation. The analysis of kinetics and steady-state properties at different [H+]o and [Cl−]i was carried out using a gating Scheme coupled to Cl− permeation. Unlike previous results showing Vm-dependent protonation, our analysis revealed that fast gate protonation was Vm and Cl− independent and the equilibrium constant for closed–open transition of unprotonated channels was facilitated by elevated [Cl−]i in a Vm-dependent manner. Hence a Vm dependence of pore occupancy by Cl− induces a conformational change in unprotonated closed channels, before the pore opens, and the open conformation is stabilized by Cl− occupancy and Vm-independent protonation. PMID:22753549

Osteogenic differentiation capacity of human skeletal muscle-derived progenitor cells.

PubMed

Oishi, Teruyo; Uezumi, Akiyoshi; Kanaji, Arihiko; Yamamoto, Naoki; Yamaguchi, Asami; Yamada, Harumoto; Tsuchida, Kunihiro

2013-01-01

Heterotopic ossification (HO) is defined as the formation of ectopic bone in soft tissue outside the skeletal tissue. HO is thought to result from aberrant differentiation of osteogenic progenitors within skeletal muscle. However, the precise origin of HO is still unclear. Skeletal muscle contains two kinds of progenitor cells, myogenic progenitors and mesenchymal progenitors. Myogenic and mesenchymal progenitors in human skeletal muscle can be identified as CD56(+) and PDGFRα(+) cells, respectively. The purpose of this study was to investigate the osteogenic differentiation potential of human skeletal muscle-derived progenitors. Both CD56(+) cells and PDGFRα(+) cells showed comparable osteogenic differentiation potential in vitro. However, in an in vivo ectopic bone formation model, PDGFRα(+) cells formed bone-like tissue and showed successful engraftment, while CD56(+) cells did not form bone-like tissue and did not adapt to an osteogenic environment. Immunohistological analysis of human HO sample revealed that many PDGFRα(+) cells were localized in proximity to ectopic bone formed in skeletal muscle. MicroRNAs (miRNAs) are known to regulate many biological processes including osteogenic differentiation. We investigated the participation of miRNAs in the osteogenic differentiation of PDGFRα(+) cells by using microarray. We identified miRNAs that had not been known to be involved in osteogenesis but showed dramatic changes during osteogenic differentiation of PDGFRα(+) cells. Upregulation of miR-146b-5p and -424 and downregulation of miR-7 during osteogenic differentiation of PDGFRα(+) cells were confirmed by quantitative real-time RT-PCR. Inhibition of upregulated miRNAs, miR-146b-5p and -424, resulted in the suppression of osteocyte maturation, suggesting that these two miRNAs have the positive role in the osteogenesis of PDGFRα(+) cells. Our results suggest that PDGFRα(+) cells may be the major source of HO and that the newly identified miRNAs may regulate osteogenic differentiation process of PDGFRα(+) cells.

An inter-comparison of HO2 measured by Fluorescence Assay by Gas Expansion and Cavity Ringdown Spectroscopy in the Highly Instrumented Reactor for Atmospheric Chemistry.

NASA Astrophysics Data System (ADS)

Brennan, A.; Onel, L. C.; Gianella, M.; Ronnie, G.; Aguila, A. L.; Hancock, G.; Whalley, L.; Seakins, P. W.; Ritchie, G.; Heard, D. E.

2017-12-01

HO2 is an important species in the atmosphere, as it is involved in the HOx radical reaction cycle that is critical to the oxidation of atmospheric pollutants and the ultimate cleaning of the troposphere. One of the most widely utilised methods to measure HO2 is Fluorescence Assay by Gas Expansion (FAGE), which indirectly measures HO2 by sampling into a low pressure cell and titrating HO2 with NO to produce OH that is then detected by Laser Induced Fluorescence. This is an indirect and non-absolute detection technique that requires careful calibration to convert the measured signal into [HO2], which involves the photolysis of H2O at 185 nm to produce OH and HO2, and is subject to 30 % errors at 2σ level. The work presented here shows the validation of the FAGE technique and its calibration procedure through inter-comparison experiments between the non-absolute FAGE technique and Cavity Ringdown Spectroscopy (CRDS), an absolute absorption based method. The CRDS system was used to excite the first O-H overtone of the HO2 absorption band at 1506.43 nm, and features a cavity length of 1.2 m and a total path of 60 km. The experiments were performed inside the 2.25 m3 stainless steel Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC), using a synthetic air mixture at 150 and 1000 mbar of pressure and 298 K. HO2 was generated by photolysis of Cl2 at 365 nm in the presence of CH3OH and O2, and the [HO2] was monitored using both instruments. Additionally, monitoring the temporal decay of HO2 during its self-reaction provided an alternative calibration method for the FAGE instrument, and allowed the absorption cross section of HO2 at 1506.43 nm, σHO2, to be measured. FAGE calibration factors determined through the second order decays of HO2 at 1000 mbar agreed within 8 % of the H2O photolysis method, and determinations of σHO2 at 150 and 1000 mbar agree with previously reported data within 20 % and 12 % respectively. [HO2] correlation plots between the two instruments at 150 and 1000 mbar showed very good agreements of 0.863 ± 0.004 and 0.903 ± 0.002 respectively. This consistency between the indirect FAGE and direct CRDS measurements of HO2 validates the FAGE method, which is widely used for field measurements of HO2 in the troposphere.

Production, fertility, survival, and body measurements of Montbéliarde-sired crossbreds compared with pure Holsteins during their first 5 lactations.

PubMed

Hazel, A R; Heins, B J; Seykora, A J; Hansen, L B

2014-01-01

Two-breed crossbreds of Montbéliarde and Holstein (MO × HO) as well as 3-breed crossbreds of Montbéliarde and Jersey/Holstein (MO × JH) were compared with pure Holstein (HO) cows for production, somatic cell score (SCS), fertility, survival to subsequent calving, mortality, and body measurements during their first 5 lactations. Cows calved for the first time between 2005 and 2010 and were housed in either a confinement herd or a herd that had access to pasture for 165d of the year in the north central region of the United States. Body, hoof, and udder measurements of cows were also objectively measured. The MO × HO crossbred cows were not different from pure HO cows for fat-plus-protein production during any lactation. However, the MO × JH crossbred cows had 5% lower fat-plus-protein production compared with pure HO cows in the confinement herd. On the other hand, the MO × JH crossbred cows were not different for fat-plus-protein production in the third to fifth lactation compared with pure HO cows in the seasonal pasture herd. Across the 2 herds, the MO × HO and MO × JH crossbred cows had 21% higher first-service conception rate, 41 fewer days open, and 12% higher pregnancy rate compared with the pure HO cows. Furthermore, the MO × HO (5%) and MO × JH (12%) crossbred cows had lower mortality rates than the pure HO cows (18%). Because of superior fertility and lower mortality rates, the MO × HO and MO × JH crossbred cows, combined, had greater survival to second (+13%), third (+24%), fourth (+25%), and fifth (+17%) lactation compared with pure HO cows. For body measurements, MO × HO were similar to pure HO cows for hip height and heart girth, but MO × HO cows had more body condition and greater body weight (+39kg) across the first 5 lactations. The MO × JH cows had more body condition but 5cm shorter hip height and 28kg less body weight than pure HO cows across the first 5 lactations. Foot angle was steeper and hoof length was shorter for MO × HO cows, but MO × JH cows were similar to pure HO cows for hoof measurements. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

High Energy Directly Pumped Ho:YLF Laser

NASA Technical Reports Server (NTRS)

Petros, Mulugeta; Yu, Ji-Rong; Singh, Upendra N.; Barnes, Norman P.

2000-01-01

The most commonly used crystal architecture to produce 2 micrometer laser is co-doping Ho and Tm into a single host crystal. In this method, the stored energy transfer from the Tm (3)F4 to the Ho (5)I7 manifold is not fast enough to warrant high efficiency for short pulse applications. By separating the Ho and the Tm ions and doping the Tm in YALO3 and the Ho in YLF, we were able to directly pump the Ho (5)I7 manifold with 1.94 micrometers. The Ho:YLF laser has produced 33 mJ at 2.062 micrometers with a quantum efficiency of 0.88. The performance of each laser will be presented.

Hydroxyl radical measurements and oxidation capacity in a boreal forest environment

NASA Astrophysics Data System (ADS)

Hens, K.; Tatum Ernest, C.; Novelli, A.; Paasonen, P.; Sipilä, M.; Petäjä, T.; Nölscher, A.; Taraborrelli, D.; Keronen, P.; Trawny, K.; Kubistin, D.; Oswald, R.; Axinte, R.; Hosaynali Beygi, Z.; Auld, J.; Klüpfel, T.; Mesarchaki, E.; Song, W.; Valverde Canossa, J.; González Orozco, D.; Königstedt, R.; Bohn, B.; Rudolf, M.; Fischer, H.; Williams, J.; Crowley, J.; Martinez, M.; Harder, H. D.; Lelieveld, J.

2012-12-01

Forests cover about one third of the earth's total land surface and are known to be an important global source of biogenic volatile organic compounds (BVOCs) that are partly very reactive towards OH. Different types of forests are known to emit various characteristic BVOCs significantly influencing atmospheric oxidation chemistry. Measurements of OH and HO2 radicals in forest environments, however, reveal a serious lack of understanding of the underlying processes. The HUMPPA-COPEC intensive field campaign took place in summer 2010 at the SMEAR II station, located in Hyytiälä, Southern Finland, as collaboration between the Max Planck Institute for Chemistry and the University of Helsinki. The main goal of the campaign was to investigate the summertime emissions and photochemistry in a boreal forest. Comprehensive measurements including observations of many VOCs, HOx, and total OH reactivity were conducted to increase our understanding of atmospheric self-cleaning processes based on detailed analysis of production and loss mechanisms of the hydroxyl radical. Also the HOx budget in a coniferous forest was examined by using direct calculations from measured species as well as an observationally constrained chemical box model in steady state. For HUMPPA-COPEC chemical reaction schemes considering isoprene as the predominant primary BVOC lead to an over prediction of the measured OH concentration by a factor of up to 4. However, only a minor fraction of the measured total OH reactivity can be explained by measured isoprene. A preliminary terpene mechanism, taking the most abundant terpenes measured during HUMPPA-COPEC-2010 and their oxidation products into account, improves the agreement between simulated and measured OH, but is not sufficient to explain the missing OH reactivity in all cases. HO2 is described reasonably well by the model for conditions where the modeled and measured total OH reactivity agree. For lower than measured reactivity, the HO2 mixing ratios are significantly under predicted indicating that the missing reactivity is an unaccounted source of HO2. An additional α-pinene equivalent is introduced into the model to match the measured total OH reactivity with the simulated one. The modification of the chemical mechanism is analyzed and discussed.

Preparation and spectroscopic characterization of two HoCl 3-galactitol complexes and one ErCl 3-galactitol complex

NASA Astrophysics Data System (ADS)

Hua, Xiaohui; Pan, Qinghua; Yu, Lei; Xue, Junhui; Yang, Limin; Xu, Yizhuang; Zhao, Guozhong; Li, Weihong; Wang, Zheming; Wu, Jinguang; Liu, Kexin; Chen, Jia'er

2011-07-01

The interactions between metal ions and hydroxyl groups of carbohydrates are important for their possible biological activities. Here two HoCl 3-galactitol complexes ([Ho(galac)(H 2O) 3)]Cl 3·0.5galac) (HoG(I)) and ([Ho 2(galac)(H 2O) 12)]Cl 6·2H 2O) (HoG(II))) and one ErCl 3-galactitol complex ([Er(galac)(H 2O) 3)]Cl 3·0.5galac)(ErG)) were prepared and characterized. The possible structures of HoG(I) and ErG were deduced from FTIR, elemental analysis, ESI-MS, FIR, THz and TGA results. It is suggested that Ho 3+ or Er 3+ is 9-coordinated with six hydroxyl groups from two galactitol molecules and three water molecules, and another galactitol molecule is hydrogen-bonded in HoG(I) and ErG and the ratio of metal to ligand is 1:1.5. The structure of HoG(II) was determined by FTIR and X-ray diffraction analyses. The results demonstrate that lanthanide ions with galactitol may form two compounds in a system and different topological structures can be obtained.

The Ce-Ni-Si system as a representative of the rare earth-Ni-Si family: Isothermal section and new rare-earth nickel silicides

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

Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru; Knotko, A.V.; Garshev, A.V.

The Ce-Ni-Si system has been investigated at 870/1070 K by X-ray and microprobe analyses. The existence of the known compounds, i.e.: Ce{sub 2}Ni{sub 15.8}Si{sub 1.2} (Th{sub 2}Ni{sub 17}-type), Ce{sub 2}Ni{sub 15-14}Si{sub 2-3} (Th{sub 2}Zn{sub 17}-type), CeNi{sub 8.6}Si{sub 2.4} (BaCd{sub 11}-type), CeNi{sub 8.8}Si{sub 4.2} (LaCo{sub 9}Si{sub 4}-type), CeNi{sub 6}Si{sub 6} (CeNi{sub 6}Si{sub 6}-type), CeNi{sub 5}Si{sub 1-0.3} (TbCu{sub 7}-type), CeNi{sub 4}Si (YNi{sub 4}Si-type), CeNi{sub 2}Si{sub 2} (CeGa{sub 2}Al{sub 2}-type), Ce{sub 2}Ni{sub 3}Si{sub 5} (U{sub 2}Co{sub 3}Si{sub 5}-type), Ce{sub 3}Ni{sub 6}Si{sub 2} (Ce{sub 3}Ni{sub 6}Si{sub 2}-type), Ce{sub 3}Ni{sub 4}Si{sub 4} (U{sub 3}Ni{sub 4}Si{sub 4}-type), CeNiSi{sub 2} (CeNiSi{sub 2}-type), ~CeNi{sub 1.3}Si{sub 0.7} (unknown typemore » structure), Ce{sub 6}Ni{sub 7}Si{sub 4} (Pr{sub 6}Ni{sub 7}Si{sub 4}-type), CeNiSi (LaPtSi-type), CeNi{sub 0.8-0.3}Si{sub 1.2-1.7} (AlB{sub 2}-type), ~Ce{sub 2}Ni{sub 2}Si (unknown type structure), ~Ce{sub 4.5}Ni{sub 3.5}Si{sub 2} (unknown type structure), Ce{sub 15}Ni{sub 7}Si{sub 10} (Pr{sub 15}Ni{sub 7}Si{sub 10}-type), Ce{sub 5}Ni{sub 1.85}Si{sub 3} (Ce{sub 5}Ni{sub 1.85}Si{sub 3}-type), Ce{sub 6}Ni{sub 1.4}Si{sub 3.4} (Ce{sub 6}Ni{sub 1.67}Si{sub 3}-type), Ce{sub 7}Ni{sub 2}Si{sub 5} (Ce{sub 7}Ni{sub 2}Si{sub 5}-type) and Ce{sub 3}NiSi{sub 3} (Y{sub 3}NiSi{sub 3}-type) has been confirmed in this section. Moreover, the type structure has been determined for ~Ce{sub 2}Ni{sub 2}Si (Mo{sub 2}NiB{sub 2}-type Ce{sub 2}Ni{sub 2.5}Si{sub 0.5}) and ~Ce{sub 4.5}Ni{sub 3.5}Si{sub 2} (W{sub 3}CoB{sub 3}-type Ce{sub 3}Ni{sub 3-2.7}Si{sub 1-1.3}) and new ternary phases Ce{sub 2}Ni{sub 6.25}Si{sub 0.75} (Gd{sub 2}Co{sub 7}-type), CeNi{sub 7-7.6}Si{sub 6-5.4} (GdNi{sub 7}Si{sub 6}-type) and ~Ce{sub 27}Ni{sub 42}Si{sub 31} (unknown type structure) have been identified in this system. Quasi-binary phases, solid solutions, were detected at 870/1070 K for CeNi{sub 5}, CeNi{sub 3} and CeSi{sub 2}; while no appreciable solubility was observed for the other binary compounds of the Ce-Ni-Si system. As a prolongation of Rare Earth-Ni-Si system’s isostructural rows, LaNi{sub 7}Si{sub 6} and YNi{sub 6.6}Si{sub 6.1} (GdNi{sub 7}Si{sub 6}-type), ScNi{sub 6}Si{sub 6} (YCo{sub 6}Ge{sub 6}-type), NdNi{sub 6}Si{sub 6} (YNi{sub 6}Si{sub 6}-type), (Tb, Ho){sub 2}Ni{sub 15}Si{sub 2} (Th{sub 2}Zn{sub 17}-type), Nd{sub 2}Ni{sub 2.3}Si{sub 0.7} and Sm{sub 2}Ni{sub 2.2}Si{sub 0.8} (Mo{sub 2}NiB{sub 2}-type), Nd{sub 3}Ni{sub 2.55}Si{sub 1.45} (W{sub 3}CoB{sub 3}-type) and (Tb, Dy){sub 7}Ni{sub 50}Si{sub 19} (Y{sub 7}Ni{sub 49}Si{sub 20}-type) compounds were synthesized and investigated. Magnetic properties of the CeNi{sub 6}Si{sub 6}, CeNi{sub 7}Si{sub 6}, CeNi{sub 8.8}Si{sub 4.2}, Ce{sub 6}Ni{sub 7}Si{sub 4}, CeNi{sub 5}Si, Ce{sub 2}Ni{sub 2.5}Si{sub 0.5}, Nd{sub 2}Ni{sub 2.3}Si{sub 0.7} and Dy{sub 7}Ni{sub 50}Si{sub 19} compounds have also been investigated and are presented here. - Highlights: • Ce-Ni-Si isothermal section was obtained at 870/1070 K. • Twenty one known ternary cerium nickel silicides were confirmed in Ce-Ni-Si. • Five new cerium nickel silicides were detected in Ce-Ni-Si. • Eleven new rare earth nickel silicides were detected in R-Ni-Si. • Magnetic properties of eight rare earth nickel silicides were investigated.« less

Do Postoperative Biomechanical Changes Induce Heterotopic Ossification After Cervical Arthroplasty?: A 5-Year Follow-up Study.

PubMed

Kim, Keun Su; Heo, Dong Hwa

2016-07-01

Prospective clinical study. To evaluate the factors that would predispose a patient to heterotopic ossification (HO) formation after cervical arthroplasty. HO after arthroplasty is one of the complications of cervical total disk replacement (TDR). However, the predisposing factors and pathophysiology of HO have not been precisely described. We prospectively enrolled and followed up 23 patients, who received single-level arthroplasty with ProDisc-C, for 5 years after the operation. The patients who developed grade 3 or 4 HO were classified into the "high-grade HO group," whereas the patients with grade 0, 1, or 2 HO were classified into the "low-grade HO group." We compared the postoperative changes in the range of motion (ROM) and height of the functional segmental unit (FSU) of the implantation segments between the 2 groups. The mean differences in height and ROM of the FSU were 2.59±1.42 mm and 6.7±3.2 degrees in the high-grade HO group, and 0.87±0.72 mm and 3.1±2.8 degrees in the low-grade HO group. The mean differences in height and ROM of the FSU were significantly higher in the high-grade HO group than in the low-grade HO group (P<0.05). After cervical arthroplasty, the height of the FSU and ROM of the implantation segments were significantly increased in the high-grade HO group compared with the low-grade HO group. Overcorrection of the height of the FSU and increase in the ROM of the implantation segment may influence the formation of HOs after cervical arthroplasty.

Protein/Protein Interactions in the Mammalian Heme Degradation Pathway

PubMed Central

Spencer, Andrea L. M.; Bagai, Ireena; Becker, Donald F.; Zuiderweg, Erik R. P.; Ragsdale, Stephen W.

2014-01-01

Heme oxygenase (HO) catalyzes the rate-limiting step in the O2-dependent degradation of heme to biliverdin, CO, and iron with electrons delivered from NADPH via cytochrome P450 reductase (CPR). Biliverdin reductase (BVR) then catalyzes conversion of biliverdin to bilirubin. We describe mutagenesis combined with kinetic, spectroscopic (fluorescence and NMR), surface plasmon resonance, cross-linking, gel filtration, and analytical ultracentrifugation studies aimed at evaluating interactions of HO-2 with CPR and BVR. Based on these results, we propose a model in which HO-2 and CPR form a dynamic ensemble of complex(es) that precede formation of the productive electron transfer complex. The 1H-15N TROSY NMR spectrum of HO-2 reveals specific residues, including Leu-201, near the heme face of HO-2 that are affected by the addition of CPR, implicating these residues at the HO/CPR interface. Alanine substitutions at HO-2 residues Leu-201 and Lys-169 cause a respective 3- and 22-fold increase in Km values for CPR, consistent with a role for these residues in CPR binding. Sedimentation velocity experiments confirm the transient nature of the HO-2·CPR complex (Kd = 15.1 μm). Our results also indicate that HO-2 and BVR form a very weak complex that is only captured by cross-linking. For example, under conditions where CPR affects the 1H-15N TROSY NMR spectrum of HO-2, BVR has no effect. Fluorescence quenching experiments also suggest that BVR binds HO-2 weakly, if at all, and that the previously reported high affinity of BVR for HO is artifactual, resulting from the effects of free heme (dissociated from HO) on BVR fluorescence. PMID:25196843

Heme oxygenase-1 expression protects the heart from acute injury caused by inducible Cre recombinase

PubMed Central

Hull, Travis D.; Bolisetty, Subashini; DeAlmeida, Angela; Litovsky, Silvio H.; Prabhu, Sumanth D.; Agarwal, Anupam; George, James F.

2013-01-01

The protective effect of heme oxygenase-1 (HO-1) expression in cardiovascular disease has been previously demonstrated using transgenic animal models in which HO-1 is constitutively overexpressed in the heart. However, the temporal requirements for protection by HO-1 induction relative to injury have not been investigated, but are essential to employ HO-1 as a therapeutic strategy in human cardiovascular disease states. Therefore, we generated mice with cardiac-specific, tamoxifen (TAM)-inducible overexpression of a human HO-1 (hHO-1) transgene (MHC-HO-1 mice) by breeding mice with cardiac-specific expression of a TAM-inducible Cre recombinase (MHC-Cre mice) with mice containing an hHO-1 transgene preceded by a floxed stop signal (CBA-flox mice). MHC-HO-1 overexpress the HO-1 gene and enzymatically protein following TAM administration (40 mg/kg body weight on two consecutive days). In MHC-Cre controls, TAM administration leads to severe, acute cardiac toxicity, cardiomyocyte necrosis, and 80% mortality by day 3. This cardiac toxicity is accompanied by a significant increase in inflammatory cells in the heart that are predominantly neutrophils. In MHC-HO-1 mice, HO-1 overexpression ameliorates the depression of cardiac function and high mortality rate observed in MHC-Cre mice following TAM administration and attenuates cardiomyocyte necrosis and neutrophil infiltration. These results highlight that HO-1 induction is sufficient to prevent the depression of cardiac function observed in mice with TAM-inducible Cre recombinase expression by protecting the heart from necrosis and neutrophil infiltration. These findings are important because MHC-Cre mice are widely used in cardiovascular research despite the limitations imposed by Cre-induced cardiac toxicity and also because inflammation is an important pathological component of many human cardiovascular diseases. PMID:23732814

Heme oxygenase-1 expression protects the heart from acute injury caused by inducible Cre recombinase.

PubMed

Hull, Travis D; Bolisetty, Subhashini; DeAlmeida, Angela C; Litovsky, Silvio H; Prabhu, Sumanth D; Agarwal, Anupam; George, James F

2013-08-01

The protective effect of heme oxygenase-1 (HO-1) expression in cardiovascular disease has been previously demonstrated using transgenic animal models in which HO-1 is constitutively overexpressed in the heart. However, the temporal requirements for protection by HO-1 induction relative to injury have not been investigated, but are essential to employ HO-1 as a therapeutic strategy in human cardiovascular disease states. Therefore, we generated mice with cardiac-specific, tamoxifen (TAM)-inducible overexpression of a human HO-1 (hHO-1) transgene (myosin heavy chain (MHC)-HO-1 mice) by breeding mice with cardiac-specific expression of a TAM-inducible Cre recombinase (MHC-Cre mice), with mice containing an hHO-1 transgene preceded by a floxed-stop signal. MHC-HO-1 mice overexpress HO-1 mRNA and the enzymatically active protein following TAM administration (40 mg/kg body weight on 2 consecutive days). In MHC-Cre controls, TAM administration leads to severe, acute cardiac toxicity, cardiomyocyte necrosis, and 80% mortality by day 3. This cardiac toxicity is accompanied by a significant increase in inflammatory cells in the heart that are predominantly neutrophils. In MHC-HO-1 mice, HO-1 overexpression ameliorates the depression of cardiac function and high mortality rate observed in MHC-Cre mice following TAM administration and attenuates cardiomyocyte necrosis and neutrophil infiltration. These results highlight that HO-1 induction is sufficient to prevent the depression of cardiac function observed in mice with TAM-inducible Cre recombinase expression by protecting the heart from necrosis and neutrophil infiltration. These findings are important because MHC-Cre mice are widely used in cardiovascular research despite the limitations imposed by Cre-induced cardiac toxicity, and also because inflammation is an important pathological component of many human cardiovascular diseases.

High-frequency spectral ultrasound imaging (SUSI) visualizes early post-traumatic heterotopic ossification (HO) in a mouse model.

PubMed

Ranganathan, Kavitha; Hong, Xiaowei; Cholok, David; Habbouche, Joe; Priest, Caitlin; Breuler, Christopher; Chung, Michael; Li, John; Kaura, Arminder; Hsieh, Hsiao Hsin Sung; Butts, Jonathan; Ucer, Serra; Schwartz, Ean; Buchman, Steven R; Stegemann, Jan P; Deng, Cheri X; Levi, Benjamin

2018-04-01

Early treatment of heterotopic ossification (HO) is currently limited by delayed diagnosis due to limited visualization at early time points. In this study, we validate the use of spectral ultrasound imaging (SUSI) in an animal model to detect HO as early as one week after burn tenotomy. Concurrent SUSI, micro CT, and histology at 1, 2, 4, and 9weeks post-injury were used to follow the progression of HO after an Achilles tenotomy and 30% total body surface area burn (n=3-5 limbs per time point). To compare the use of SUSI in different types of injury models, mice (n=5 per group) underwent either burn/tenotomy or skin incision injury and were imaged using a 55MHz probe on VisualSonics VEVO 770 system at one week post injury to evaluate the ability of SUSI to distinguish between edema and HO. Average acoustic concentration (AAC) and average scatterer diameter (ASD) were calculated for each ultrasound image frame. Micro CT was used to calculate the total volume of HO. Histology was used to confirm bone formation. Using SUSI, HO was visualized as early as 1week after injury. HO was visualized earliest by 4weeks after injury by micro CT. The average acoustic concentration of HO was 33% more than that of the control limb (n=5). Spectroscopic foci of HO present at 1week that persisted throughout all time points correlated with the HO present at 9weeks on micro CT imaging. SUSI visualizes HO as early as one week after injury in an animal model. SUSI represents a new imaging modality with promise for early diagnosis of HO. Copyright © 2018 Elsevier Inc. All rights reserved.

Sofalcone, a gastric mucosa protective agent, increases vascular endothelial growth factor via the Nrf2-heme-oxygenase-1 dependent pathway in gastric epithelial cells

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

Shibuya, Akiko; Onda, Kenji, E-mail: knjond@toyaku.ac.jp; Kawahara, Hirofumi

2010-07-30

Research highlights: {yields} Sofalcone increases HO-1 in gastric epithelial cells. {yields} The induction of HO-1 by sofalcone treatment follows the activation of Nrf2. {yields} The production of VEGF by sofalcone treatment is mediated by HO-1 induction. -- Abstract: Sofalcone, 2'-carboxymethoxy-4,4-bis(3-methyl-2-butenyloxy)chalcone, is an anti-ulcer agent that is classified as a gastric mucosa protective agent. Recent studies indicate heat shock proteins such as HSP32, also known as heme-oxygenase-1(HO-1), play important roles in protecting gastrointestinal tissues from several stresses. We have previously reported that sofalcone increases the expression of HO-1 in adipocytes and pre-adipocytes, although the effect of sofalcone on HO-1 induction inmore » gastrointestinal tissues is not clear. In the current study, we investigated the effects of sofalcone on the expression of HO-1 and its functional role in rat gastric epithelial (RGM-1) cells. We found that sofalcone increased HO-1 expression in RGM-1 cells in both time- and concentration-dependent manners. The HO-1 induction was associated with the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in RGM-1 cells. We also observed that sofalcone increased vascular endothelial growth factor (VEGF) production in the culture medium. Treatment of RGM-1 cells with an HO-1 inhibitor (tin-protoporphyrin), or HO-1 siRNA inhibited sofalcone-induced VEGF production, suggesting that the effect of sofalcone on VEGF expression is mediated by the HO-1 pathway. These results suggest that the gastroprotective effects of sofalcone are partly exerted via Nrf2-HO-1 activation followed by VEGF production.« less

Effects of treatment of periparturient dairy cows with recombinant bovine somatotropin on health and productive and reproductive parameters.

PubMed

Silva, P R B; Soares, H F; Braz, W D; Bombardelli, G D; Clapper, J A; Keisler, D H; Chebel, R C

2017-04-01

The objectives of the current experiment were to evaluate the effects of treating periparturient dairy cows with recombinant bovine somatotropin (rbST) on incidence of postpartum diseases and performance. Holstein (HO) and Jersey (JS) cows from 2 herds were enrolled in the experiment at 253 ± 3 d of gestation and assigned to the control (n = 432) and rbST125 (n = 437) treatments. Cows in the rbST125 treatment received 125 mg of rbST, weekly, from -21 to 21 d relative to calving. Blood sampled weekly, from -21 to 21 d relative to calving, from a subsample of cows was used to determine the concentrations of growth hormone (GH, HO = 106) and insulin-like growth factor 1 (IGF-1, HO = 147 and JS = 49). Cows were scored for body condition (BCS) at enrollment and at 1 ± 3, 30 ± 3, and 60 ± 3 d in milk (DIM). Cows were milked thrice daily and energy-corrected milk (ECM) yield was recorded for the first 30 DIM. Treatment of cows with rbST resulted in greater concentrations of GH during the prepartum (log 10 back-transformed concentrations of GH: HO-control = 7.83 and HO-rbST125 = 10.36 ng/mL) and postpartum (log 10 back-transformed concentrations of GH: HO-control = 10.45 and HO-rbST125 = 18.47 ng/mL) periods. Similarly, IGF-1 concentrations were higher during the prepartum (HO-control = 115.1 ± 4.9, HO-rbST125 = 137.7 ± 4.7, JS-control = 120.2 ± 8.3, JS-rbST125 = 167.1 ± 8.1 ng/mL) and postpartum (HO-control = 61.3 ± 4.0, HO-rbST125 = 75.2 ± 3.8, JS-control = 35.5 ± 6.9, JS-rbST125 = 54.6 ± 6.9 ng/mL) periods for rbST-treated cows. During the prepartum period, BCS was not affected by treatment, but during the postpartum period, BCS was reduced for rbST-treated cows (HO-control = 3.00 ± 0.03, HO-rbST125 = 2.90 ± 0.03, JS-control = 2.64 ± 0.02, JS-rbST125 = 2.61 ± 0.02). Cows from the rbST125 treatment tended to have lower incidence of retained fetal membranes (HO-control = 14.3, HO-rbST125 = 6.1, JS-control = 1.5, JS-rbST125 = 1.2%) and had reduced incidence of metritis (HO-control = 26.2, HO-rbST125 = 16.6, JS-control = 19.9, JS-rbST125 = 13.3%) compared with control cows. Ketosis incidence tended to be higher for rbST125 cows (HO-control = 9.4, HO-rbST125 = 11.3, JS-control = 8.5, JS-rbST125 = 13.4%) compared with control cows. The interaction between treatment and herd tended to affect yield of ECM during the first 30 DIM because HO cows treated with rbST during the periparturient period had greater yield than control HO cows (HO-control = 35.5 ± 1.0 vs. HO-rbST125 = 39.4 ± 1.0 kg/d), but treatment with rbST did not affect yield of ECM of JS cows (JS-control = 26.7 ± 0.6 vs. JS-rbST125 = 27.8 ± 0.6 kg/d). Treatment of periparturient dairy cows with 125 mg of rbST decreased the incidence of uterine disorders in HO and JS cows and increased yield of ECM during the first 30 DIM among HO cows, despite slightly increasing the incidence of ketosis. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Enhanced performance of amorphous In-Ga-Zn-O thin-film transistors using different metals for source/drain electrodes

NASA Astrophysics Data System (ADS)

Pyo, Ju-Young; Cho, Won-Ju

2017-09-01

In this paper, we propose an amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) with off-planed source/drain electrodes. We applied different metals for the source/drain electrodes with Ni and Ti to control the work function as high and low. When we measured the configuration of Ni to drain and source to Ti, the a-IGZO TFT showed increased driving current, decreased leakage current, a high on/off current ratio, low subthreshold swing, and high mobility. In addition, we conducted a reliability test with a gate bias stress test at various temperatures. The results of the reliability test showed the Ni drain and Ti drain had an equivalent effective energy barrier height. Thus, we confirmed that the proposed off-planed structure improved the electrical characteristics of the fabricated devices without any degradation of characteristics. Through the a-IGZO TFT with different source/drain electrode metal engineering, we realized high-performance TFTs for next-generation display devices.

Deflection in Tapered Cantilever Beams Deflection (Gap Opening) in Double Cantilever Type Fracture Toughness Specimens.

DTIC Science & Technology

1985-08-01

o10 ------- --------- tx] (26) t 5 t bE ho 2(h0+tx) 2 and as before 12 9 1 p ho + tx 2ho + 3tx bend3 + bE ho 2(ho+tX)2 txcos2 At the limit, as t...h0+tx) 2tx Therefore P 1 x P x lim 6 bend3 n2 -(-) - 4 -(;) t+o bE 3ho bE h 22 which, except for the sign, is the same as that arrived at in Eq. (9

Actively mode-locked Tm-Ho:LiYF4 and Tm-Ho:BaY2F8 lasers

NASA Astrophysics Data System (ADS)

Gatti, D.; Galzerano, G.; Toncelli, A.; Tonelli, M.; Laporta, P.

2007-01-01

We report on the generation of mode-locking pulse trains with high average output powers from diode-pumped Tm-Ho:LiYF4 and Tm-Ho:BaY2F8 lasers emitting at around 2 μm. The highest output power of 365 mW was obtained with the Tm-Ho:YLF4 laser, whereas the shortest pulse duration of 120 ps and the widest tunability range of 59 nm was achieved with the Tm-Ho:BaY2F8 laser.

Beta particle transport and its impact on betavoltaic battery modeling.

PubMed

Alam, Tariq R; Pierson, Mark A; Prelas, Mark A

2017-12-01

Simulation of beta particle transport from a Ni-63 radioisotope in silicon using the Monte Carlo N-Particle (MCNP) transport code for monoenergetic beta particle average energy, monoenergetic beta particle maximum energy, and the more precise full beta energy spectrum of Ni-63 were demonstrated. The beta particle penetration depth and the shape of the energy deposition varied significantly for different transport approaches. A penetration depth of 2.25±0.25µm with a peak in energy deposition was found when using a monoenergetic beta particle average energy and a depth of 14.25±0.25µm with an exponential decrease in energy deposition was found when using a full beta energy spectrum and a 0° angular variation. For a 90° angular variation, i.e. an isotropic source, the penetration depth was decreased to 12.75±0.25µm and the backscattering coefficient increased to 0.46 with 30.55% of the beta energy escaping when using a full beta energy spectrum. Similarly, for a 0° angular variation and an isotropic source, an overprediction in the short circuit current and open circuit voltage solved by a simplified drift-diffusion model was observed when compared to experimental results from the literature. A good agreement in the results was found when self-absorption and isotope dilution in the source was considered. The self-absorption effect was 15% for a Ni-63 source with an activity of 0.25mCi. This effect increased to about 28.5% for a higher source activity of 1mCi due to an increase in thickness of the Ni-63 source. Source thicknesses of approximately 0.1µm and 0.4µm for these Ni-63 activities predicted about 15% and 28.5% self-absorption in the source, respectively, using MCNP simulations with an isotropic source. The modeling assumptions with different beta particle energy inputs, junction depth of the semiconductor, backscattering of beta particles, an isotropic beta source, and self-absorption of the radioisotope have significant impacts in betavoltaic battery design. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Central Role for Heme Oxygenase-1 in the Control of Intestinal Epithelial Chemokine Expression.

PubMed

Onyiah, Joseph C; Schaefer, Rachel E M; Colgan, Sean P

2018-05-23

In mucosal inflammatory disorders, the protective influence of heme oxygenase-1 (HO-1) and its metabolic byproducts, carbon monoxide (CO) and biliverdin, is a topic of significant interest. Mechanisms under investigation include the regulation of macrophage function and mucosal cytokine expression. While there is an increasing recognition of the importance of epithelial-derived factors in the maintenance of intestinal mucosal homeostasis, the contribution of intestinal epithelial cell (IEC) HO-1 on inflammatory responses has not previously been investigated. We examined the influence of modulating HO-1 expression on the inflammatory response of human IECs. Engineered deficiency of HO-1 in Caco-2 and T84 IECs led to increased proinflammatory chemokine expression in response to pathogenic bacteria and inflammatory cytokine stimulation. Crosstalk with activated leukocytes also led to increased chemokine expression in HO-1-deficient cells in an IL-1β dependent manner. Treatment of Caco-2 cells with a pharmacological inducer of HO-1 led to the inhibition of chemokine expression. Mechanistic studies suggest that HO-1 and HO-1-related transcription factors, but not HO-1 metabolic products, are partly responsible for the influence of HO-1 on chemokine expression. In conclusion, our data identify HO-1 as a central regulator of IEC chemokine expression that may contribute to homeo-stasis in the intestinal mucosa. © 2018 S. Karger AG, Basel.

Heme oxygenase: the key to renal function regulation

PubMed Central

Cao, Jian; Sacerdoti, David; Li, Xiaoying; Drummond, George

2009-01-01

Heme oxygenase (HO) plays a critical role in attenuating the production of reactive oxygen species through its ability to degrade heme in an enzymatic process that leads to the production of equimolar amounts of carbon monoxide and biliverdin/bilirubin and the release of free iron. The present review examines the beneficial role of HO-1 (inducible form of HO) that is achieved by increased expression of this enzyme in renal tissue. The influence of the HO system on renal physiology, obesity, vascular dysfunction, and blood pressure regulation is reviewed, and the clinical potential of increased levels of HO-1 protein, HO activity, and HO-derived end products of heme degradation is discussed relative to renal disease. The use of pharmacological and genetic approaches to investigate the role of the HO system in the kidney is key to the development of therapeutic approaches to prevent the adverse effects that accrue due to an impairment in renal function. PMID:19570878

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

Başar, Gö.; Güzelçimen, F.; Er, A.

Fourier Transform spectra of holmium (Ho) in the UV spectral range from 31,530 to 25,000 cm{sup −1} (317 to 400 nm) have been investigated, particularly focusing on the ionic lines. The distinction between the different degrees of ionization (I, II, and III) is based on differences in signal-to-noise ratios from two Ho spectra, which have been measured with different buffer gases, i.e., neon and argon. Based on 106 known Ho ii and 126 known Ho iii energy levels, 97 lines could be classified as transitions of singly ionized Ho and 9 lines could be classified as transitions of doubly ionized Ho.more » Of the 97 Ho ii lines, 6 have not been listed in the extant literature. Another 215 lines have been assigned to Ho ii, though they could not be classified on the basis of the known energy levels.« less

Tracing Sources and Contamination Assessments of Heavy Metals in Road and Foliar Dusts in a Typical Mining City, China

PubMed Central

Yang, Jie; Teng, Yanguo; Song, Liuting; Zuo, Rui

2016-01-01

Road and foliar dust samples from four land-use districts of Panzhihua City, a famous V-Ti magnetite production area of China, were collected to investigate the sources and distribution characteristics of 9 heavy metals (V, Pb, Cd, Cu, Zn, Ni, Cr, Fe, and Mn). The results suggest that foliar samples had smaller particle size and higher heavy metal contents than road dusts. The contamination assessments of heavy metals were as follows: Pb and V (significant enrichment) > Zn, Ni, Cr, Fe, and Mn (moderate enrichment) > Cd and Ni (minimal enrichment). Statistical analyses showed Pb, as the primary pollution element, originated from waste incineration and lead-fuel combustion. The sources of Zn, Ni, Cr, Fe, V, and Mn were fugitive dust and traffic activities. Potential origins of Cu were corrosion of alloys used in vehicle components, vehicle covers, or other metallic surfaces and materials. The sources of Cd were different from any other heavy metals. Traffic and industrial activities were the main anthropogenic origins of heavy metals in dusts of Panzhihua, and more attention should be paid to heavy metal pollution in agricultural area. PMID:27992518

Tracing Sources and Contamination Assessments of Heavy Metals in Road and Foliar Dusts in a Typical Mining City, China.

PubMed

Yang, Jie; Teng, Yanguo; Song, Liuting; Zuo, Rui

2016-01-01

Road and foliar dust samples from four land-use districts of Panzhihua City, a famous V-Ti magnetite production area of China, were collected to investigate the sources and distribution characteristics of 9 heavy metals (V, Pb, Cd, Cu, Zn, Ni, Cr, Fe, and Mn). The results suggest that foliar samples had smaller particle size and higher heavy metal contents than road dusts. The contamination assessments of heavy metals were as follows: Pb and V (significant enrichment) > Zn, Ni, Cr, Fe, and Mn (moderate enrichment) > Cd and Ni (minimal enrichment). Statistical analyses showed Pb, as the primary pollution element, originated from waste incineration and lead-fuel combustion. The sources of Zn, Ni, Cr, Fe, V, and Mn were fugitive dust and traffic activities. Potential origins of Cu were corrosion of alloys used in vehicle components, vehicle covers, or other metallic surfaces and materials. The sources of Cd were different from any other heavy metals. Traffic and industrial activities were the main anthropogenic origins of heavy metals in dusts of Panzhihua, and more attention should be paid to heavy metal pollution in agricultural area.

Fabrication of Ni@Ti core-shell nanoparticles by modified gas aggregation source

NASA Astrophysics Data System (ADS)

Hanuš, J.; Vaidulych, M.; Kylián, O.; Choukourov, A.; Kousal, J.; Khalakhan, I.; Cieslar, M.; Solař, P.; Biederman, H.

2017-11-01

Ni@Ti core-shell nanoparticles were prepared by a vacuum based method using the gas aggregation source (GAS) of nanoparticles. Ni nanoparticles fabricated in the GAS were afterwards coated by a Ti shell. The Ti shell was deposited by means of magnetron sputtering. The Ni nanoparticles were decelerated in the vicinity of the magnetron to the Ar drift velocity in the second deposition chamber. X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy analysis of the nanoparticles showed the core-shell structure. It was shown that the thickness of the shell can be easily tuned by the process parameters with a maximum achieved thickness of the Ti shell ~2.5 nm. The core-shell structure was confirmed by the STEM analysis of the particles.

The TallyHo polygenic mouse model of diabetes: implications in wound healing.

PubMed

Buck, Donald W; Jin, Da P; Geringer, Matthew; Hong, Seok Jong; Galiano, Robert D; Mustoe, Thomas A

2011-11-01

Impairments in wound healing represent a significant source of morbidity and mortality in patients with diabetes. To help uncover the derangements associated with diabetic wound healing, murine animal models have been extensively used. In this article, the authors present results, and the accompanying wound healing implications, from experiments across three validated wound healing models using a newer polygenic strain of diabetes. The authors investigated the wound healing impairments of the TallyHo/JnJ diabetic mouse strain, using three validated wound healing models: an incisional model, a splinted excisional model, and a cutaneous ischemia-reperfusion injury model. Appropriate control strain mice were used for comparison. Wounds were analyzed using gross, histologic, and molecular techniques. TallyHo mice displayed deficits across all three wound healing models. There was a reduced resistance/response to oxidative stress and a global decrease in the initial inflammatory response to healing. In addition, there was a global decrease in the stimulus for angiogenesis and collagen formation, ultimately leading to reduced reepithelialization, granulation tissue formation, wound contraction, and wound tensile strength. Gross and histologic findings were corroborated with molecular data, which revealed a significant down-regulation of important cytokines, including vascular endothelial growth factor, neutrophilic attractant protein-2, monocyte chemoattractant protien-1, heme oxygenase-1, interleukin-1β, and interleukin-6, when normalized to the control strain (p<0.05). The TallyHo polygenic mouse model of diabetes demonstrates predictable and clinically relevant wound healing impairments that offer important implications into the derangements of diabetic wound healing observed clinically. Therapeutics targeting these specific derangements could provide improvements in the care of diabetic wounds.

Coping with the crisis: people with severe mental disorders acting for social change through sustainable energy.

PubMed

Carta, Mg; Sancassiani, F; Lecca, Me; Pintus, E; Pintus, M; Pisano, E; Congiu, S; Moro, Mf; Angermeyer, Cm

2013-01-01

The aim of the study was to examine the efficacy of a vocational training program on renewable energy sources in reducing disabilities of people with chronic psychosis (CP). The innovative element was that the project could produce major advantages regarding the economic needs of the whole area involved. Experimental Cohort, 26 subjects with CP (EC); Control Cohort1, 130 subjects with CP following pharmacotherapy plus other rehabilitation activities (CIC); Control Cohort2, 101 subjects with CP following the usual treatment (pharmacotherapy) (CUC). Study tool: Health of the Nation Outcome Scales (HoNOS). Assessment made at the start of the study (T0) and after three months (T1). Statistical analysis made by MANOVA. Improvement in HoNOS total score in both groups (F=7.574, p=0.000) with non-significant differences between groups over time (F=1.336, p=0.252) was found comparing EC vs. CIC. Greater improvement in EC vs. CIC was shown in the HoNOS "impairment" scale (F=4.910, p=0.028). EC vs. CUC: both groups improved in HoNOS total score (F=9.440, p=0.000) but the improvement was greater in EC (F = 2.273, P=0.048). Work inclusion, as well as other rehabilitation treatments, reduces the social needs of people with chronic psychosis. Work inclusion in a project with real relevance for the area where these people live, produces more improvement of cognitive, physical and somatic disabilities, probably related to a better outcome in self-efficacy.

Enhancing Osteoclastic Resorption for the Prevention and Treatment of Heterotopic Ossification

DTIC Science & Technology

2015-03-01

two thirds of these patients developing painful and debilitating HO. There are currently no effective treatments for HO other than surgical...prevention and treatment of HO, to relieve this painful and debilitating orthopaedic complication. American Society for Bone and Mineral Research, Houston...developing painful and debilitating HO. There are currently no effective treatments for HO other than surgical excision of the ossified tissue which

Magnetic and magnetocaloric properties of iron subs tituted holmium chromite and dysprosium chromite

DOE PAGES

Yin, Shiqi; Sharma, Vinit; McDannald, Austin; ...

2016-01-11

In this work, structural, magnetic, and magnetocaloric properties of HoCrO 3 and Fe substituted HoCrO 3 and DyCrO 3 (i.e. HoCr 0.7Fe 0.3O 3 and DyCr 0.7Fe 0.3O 3) powder samples were synthesized via a solution route. The structural properties of the samples were examined by Raman spectroscopy and x-ray diffraction techniques, which were further confirmed using first-principle calculations. The dc magnetic measurements indicate that the Cr 3+ ordering temperatures for the HoCrO 3, HoCr 0.7Fe 0.3O 3, and DyCr 0.7Fe 0.3O 3 samples are 140 K, 174 K, and 160 K, respectively. The ac magnetic measurements not only confirmedmore » the Cr 3+ ordering transitions in these samples (obtained using dc magnetic measurements), but also clearly showed the Ho 3+ ordering at ~10 K in the present HoCrO 3 and HoCr 0.7Fe 0.3O 3 samples, which to our knowledge, is the first ac magnetic evidence of Ho 3+ ordering in this system. The effective magnetic moments were determined to be 11.67μB, 11.30μB, and 11.27μB for the HoCrO 3, HoCr 0.7Fe 0.3O 3, and DyCr 0.7Fe 0.3O 3 samples, respectively. For the first time, the magnetocaloric properties of HoCrO 3 and HoCr 0.7Fe 0.3O 3 were studied here, showing their potential for applications in magnetic refrigeration. In an applied dc magnetic field of 7 T, the maximum magnetocaloric value were determined to be 7.2 (at 20 K), 6.83 (at 20 K), 13.08 J/kg K (at 5 K) and the relative cooling power were 408, 387, and 500 J/kg for the HoCrO 3, HoCr 0.7Fe 0.3O 3, and DyCr 0.7Fe 0.3O 3 samples, respectively.« less

Regulation of hemeoxygenase-1 gene expression by Nrf2 and c-Jun in tertiary butylhydroquinone-stimulated rat primary astrocytes

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

Park, Jin-Sun; Kim, Hee-Sun, E-mail: hskimp@ewha.ac.kr

2014-05-16

Highlights: • tBHQ increased HO-1 mRNA and protein levels in rat primary astrocytes. • tBHQ enhanced HO-1 gene transcription in an ARE-dependent manner. • tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. • Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. • Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction. - Abstract: Hemeoxygenase-1 (HO-1) is a phase II antioxidant enzyme that is primarily involved in detoxification and cytoprotection in a variety of tissues. However, the mechanism underlying HO-1 gene expression remains unclear. In the present study, we investigatedmore » the regulation of HO-1 expression in primary cultured astrocytes by using the natural antioxidant compound tertiary butylhydroquinone (tBHQ). We found that tBHQ increased HO-1 mRNA and protein levels. Promoter analysis revealed that tBHQ enhanced HO-1 gene transcription in an antioxidant response element (ARE)-dependent manner. In addition, tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. Small interfering RNA (siRNA) experiments demonstrated that Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. Thus, Nrf2 knockdown reduced the basal level of HO-1 expression but did not affect the fold induction by tBHQ. On the other hand, knockdown of c-Jun diminished tBHQ-mediated induction of HO-1 without affecting basal expression. The data suggest that Nrf2 generally modulates the basal expression of HO-1, while c-Jun mediates HO-1 induction in response to tBHQ. The results of co-immunoprecipitation assays demonstrated a physical interaction between Nrf2 and c-Jun in tBHQ-treated astrocytes. The results suggest that Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction in tBHQ-treated rat primary astrocytes.« less

Double-Pulsed 2-micron Laser Transmitter for Multiple Lidar Applications

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Yu, Jirong

2002-01-01

A high energy double-pulsed Ho:Tm:YLF 2-micron laser amplifier has been demonstrated. 600 mJ per pulse pair under Q-switch operation is achieved with the gain of 4.4. This solid-state laser source can be used as lidar transmitter for multiple lidar applications such as coherent wind and carbon dioxide measurements.

Molecular cloning, characterization, and expression of an alfalfa (Medicago sativa L.) heme oxygenase-1 gene, MsHO1, which is pro-oxidants-regulated.

PubMed

Fu, Guang-Qing; Xu, Sheng; Xie, Yan-Jie; Han, Bin; Nie, Li; Shen, Wen-Biao; Wang, Ren

2011-07-01

It has been documented that plant heme oxygenase-1 (HO-1; EC 1.14.99.3) is both development- and stress-regulated, thus it plays a vital role in light signalling and stress responses. In this study, an alfalfa (Medica sativa L.) HO-1 gene MsHO1 was isolated and sequenced. It contains four exons and three introns within genomic DNA sequence and encodes a polypeptide with 283 amino acids. MsHO1 had a conserved HO signature sequence and showed high similarity to other HOs in plants, especially HO-1 isoform. The MsHO1:GFP fusion protein was localized in the chloroplast. Further biochemical activity analysis of mature MsHO1, which was expressed in Escherichia coli, showed that the Vmax was 48.78 nmol biliverdin-IXα (BV) h⁻¹ nmol⁻¹ protein with an apparent Km value for hemin of 2.33 μM, and the optimum Tm and pH were 37 °C and 7.2, respectively. Results of semi-quantitative RT-PCR and western blot showed that the expressions of MsHO1 were higher in alfalfa stems and leaves than those in germinating seeds and roots. Importantly, MsHO1 gene expression and protein level were induced significantly by some pro-oxidant compounds, including hemin and nitric oxide (NO) donor sodium nitroprusside (SNP). In conclusion, MsHO1 may play an important role in oxidative responses. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

NiO and Fe/Mn in Fo-rich olivines from OIB, MORB, and mantle peridotites

NASA Astrophysics Data System (ADS)

Li, H.; Baker, M.; Hofmann, A. E.; Clague, D.; Stolper, E.

2006-12-01

Olivines from mantle peridotites have a narrow range of NiO (0.36±0.03 [1σ] wt%), but NiO of olivines in basalts suggest NiO in mantle olivines is actually more variable: e.g., Hawaiian phenocrysts (Fo>90) have NiO >0.55%, and olivines from continental flood basalts can have >0.5% NiO. At the other end of the spectrum, some basaltic suites (e.g., Iceland, MORBs) have Fo>90 olivines with NiO >0.2%. Partial melting calculations on peridotites show it is difficult to generate liquids that crystallize Fo>90 olivines with >0.4% NiO without resorting to complex processes. Hypotheses to explain the variability of NiO in mantle-derived olivines include (1) reaction of peridotite with silica-rich melts of eclogite results in decreasing modal abundance of olivine and increasing NiO in olivine [1,2]; (2) magmas with NiO-rich olivines come from sources enriched in NiO due to a core-derived component [3]. [4] proposed that high Fe/Mn of Hawaiian vs. Icelandic and MORB lavas reflect a core-derived component in their sources. Possible core incorporation is poorly constrained but FeO and NiO are expected to increase by such processes, leading to correlations between NiO and Fe/Mn in mantle rocks with significant core-derived components. We present high-precision analyses of Fo-rich olivines from OIBs, MORBs, komatiites, and mantle peridotites, focusing on NiO contents and Fe/Mn ratios. Our goal is to test hypotheses to explain elevated NiO of Fo-rich olivines in basalts. Olivines are Fo85.1-93.4; more were analyzed, but we focused on this range to avoid complications due to decreasing NiO in olivine with crystallization. Errors (1σ) are 0.01 wt% in NiO and 1.5 in Fe/Mn (wt). Our data show several features: (1) NiO contents and Fe/Mn ratios of Fo>88 olivines are positively correlated, with the low end of the trend (NiO ~0.23%, Fe/Mn ~61) defined by MORB and Iceland and the high end of the trend (NiO ~0.55%, Fe/Mn ~80) by Reunion and Hawaii. Between these end points, there is a regular trend from MORB/Iceland, to Baffin Isl, to mantle peridotites/Juan Fernandez, to Reunion/Hawaii. This array can't be explained by simple crystallization (all have similar Fo) or by variable degrees of partial melting of a single source. The NiO-Fe/Mn correlation can be modeled by quantitative addition of 1-2% oxidized core to depleted mantle and thus is consistent with the core-addition hypothesis. However, more complex core-mantle interactions/fractionations would still be required to explain trace siderophile and chalcophile elements and isotopes. Moreover, other hypotheses to explain the observed trend (including addition of silicic melts to peridotite) cannot be ruled out. (2) The Hawaiian data, although clearly defining with Reunion the upper end of the overall NiO-Fe/Mn array, are more complex. For example, a single Mauna Kea sample has ~Fo90 phenocrysts with NiO from 0.30 to 0.54%, all with Fe/Mn=72-80, and North Arch and Loihi olivines have relatively low NiO at Fe/Mn ratios comparable to other Hawaiian olivines. Although Loihi and North Arch lavas are low in SiO2, in detail the NiO of Hawaiian olivines are not well predicted by SiO2 contents of the host lavas. (3) The Gorgona Isl komatiites fall off the overall trend, extending to NiO >0.5 wt% at Fe/Mn ~62, perhaps reflecting different sources, processes, or anomalous degrees of melting. [1] Kelemen et al (1998) EPSL 164, 387-406 [2] Sobolev et al (2005) Nature 434, 590-597 [3] Ryabchikov (2003) Doklady Earth Sci. 389A, 437-439 [4] Humayun et al (2004) Science 306, 91-94

Preparation of hierarchical β-Ni(OH)2 nanostructures and adsorption characterization of methyl orange dye

NASA Astrophysics Data System (ADS)

Jiao, Shujie; Jin, Yimin; Du, Qian; Zhu, Chunguang; Gao, Shiyong; Wang, Dongbo; Wang, Jinzhong

2018-05-01

The β-Ni(OH)2 nanostructures have been prepared by hydrothermal with ammonia as alkali source. The morphology of β-Ni(OH)2 evolves from hexagon sheets to flower-like hierarchical structure built up from the nanosheets as increasing the amount of ammonia. Hierarchical β-Ni(OH)2 nanostructures have strong adsorption effect on methyl orange dyes. The adsorption mechanism of β-Ni(OH)2 has been investigated, which could be expressed by pseudo-second order kinetic model with best match.

OH, HO2 and RO2 Radical and OH Reactivity Observations during the Summertime in Beijing: High In-Situ Ozone Production and Evidence of a Missing OH Source.

NASA Astrophysics Data System (ADS)

Whalley, L.; Ye, C.; Slater, E.; Woodward-Massey, R.; Lee, J. D.; Squires, F. A.; Hopkins, J. R.; Dunmore, R.; Shaw, M.; Hamilton, J.; Lewis, A. C.; Crilley, L.; Kramer, L. J.; Bloss, W.; Heard, D. E.

2017-12-01

Despite substantial reductions in primary emissions of pollutants in China over the past decade, concentrations of the secondary pollutant, ozone, still frequently exceed air quality threshold limits in urban areas during the summertime. We will present measurements of OH, HO2 and RO2 radicals and OH reactivity made in central Beijing at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, close to the North 4th ring road in May and June 2017 which formed the summer phase of `An Integrated Study of AIR Pollution PROcesses'. Elevated levels of O3 (>100 ppbv) were regularly observed. NO concentrations were elevated during the morning but often decreased to below the instrument limit of detection during the afternoon hours when the ozone concentrations peaked. Biogenic emissions influenced the chemistry at the site, with several ppbv of isoprene measured during the afternoons. The OH measurements were made using the FAGE technique, equipped with an inlet pre injector (IPI) which provides an alternative method to determine the instrument background signal by injecting a scavenger to remove ambient OH and ensures an artefact-free OH measurement. Elevated levels of OH were observed, with a mean peak OH concentration of 1.2×107 molecule cm-3 at noon; but with OH concentrations reaching up to 2.5×107 molecule cm-3 on some days. Mean peak HO2 concentrations of 3×108 molecule cm-3 and total RO2 of 1.2×109 molecule cm-3 were recorded, with maximum concentrations of 1.0×109 molecule cm-3 and 4×109 molecule cm-3 observed for HO2 and RO2 respectively, suggesting significant in situ ozone production. A comparison of the artefact-free OH observations with steady state calculations, constrained to the total OH reactivity measurement and known OH precursors that were measured alongside OH, highlights a significant missing daytime OH source under low [NO], with the steady state OH concentrations approximately a factor of two lower than the OH concentrations observed at noon. The magnitude of this missing OH source is similar to the unexplained OH concentrations reported from other studies in China under low NO conditions as well as studies made in rainforests, implying that the uncertainty in the oxidation chemistry determined from observations in forested regions is relevant to the chemistry in urban regions also.

[Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Soils and Sediments in Shunde Waterway, Southern China].

PubMed

Cai, Yi-min; Chen, Wei-ping; Peng, Chi; Wang, Tie-yu; Xiao, Rong-bo

2016-05-15

Environmental quality of soils and sediments around water source area can influence the safety of potable water of rivers. In order to study the pollution characteristics, the sources and ecological risks of heavy metals Zn, Cr, Pb, Cu, Ni and Cd in water source area, surface soils around the waterway and sediments in the estuary of main tributaries were collected in Shunde, and ecological risks of heavy metals were assessed by two methods of potential ecological risk assessment. The mean contents of Zn, Cr, Pb, Cu, Ni and Cd in the surface soils were 186.80, 65.88, 54.56, 32.47, 22.65 and 0.86 mg · kg⁻¹ respectively, and they were higher than their soil background values except those of Cu and Ni. The mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in the sediments were 312.11, 111.41, 97.87, 92.32, 29.89 and 1.72 mg · kg⁻¹ respectively, and they were higher than their soil background values except that of Ni. The results of principal component analysis illustrated that the main source of Cr and Ni in soils was soil parent materials, and Zn, Pb, Cu and Cd in soils mainly came from wastewater discharge of local manufacturing industry. The six heavy metals in sediments mainly originated from industry emissions around the Shunde waterway. The results of potential ecological risk assessment integrating environmental bioavailability of heavy metals showed that Zn, Cu, Pb and Ni had a slight potential ecological risk. Cd had a slight potential ecological risk in surface soils, but a moderate potential ecological risk in surfaces sediments. Because the potential ecological risk assessment integrating environmental bioavailability of heavy metals took the soil properties and heavy metal forms into account, its results of risks were lower than those of Hakanson methods, and it could avoid overestimating the potential risks of heavy metals.

Regulation of rat heme oxygenase-1 expression by interleukin-6 via the Jak/STAT pathway in hepatocytes.

PubMed

Tron, Kyrylo; Samoylenko, Anatoly; Musikowski, Gernot; Kobe, Fritz; Immenschuh, Stephan; Schaper, Fred; Ramadori, Giuliano; Kietzmann, Thomas

2006-07-01

Heme oxygenase-1 (HO-1) can be induced by various stimuli, one of which is interleukin-6 (IL-6). Therefore, the aim of this study was to elucidate the molecular mechanisms responsible for IL-6-dependent HO-1 induction in the liver. The IL-6-dependent HO-1 regulation in rat primary hepatocytes and HepG2 hepatoma cells was studied by Northern and Western blot analyses, HO-1 promoter reporter gene assays and EMSA. The HO-1 expression was transcriptionally induced by IL-6 in a time- and dose-dependent manner. Activation of signal transducers and activators of transcription (STAT) factors by the IL-6 receptor was crucial for HO-1 induction. By contrast, negative regulation of HO-1 expression appeared to be mediated through the SH2-domain-containing tyrosine phosphatase-2 (SHP2)/ suppressors of cytokine signaling-3 (SOCS3) binding site within the gp130 IL-6 receptor subunit. Among the three putative STAT binding elements (SBE) in the HO-1 promoter, only the distal one was functional and when deleted, the remaining Luc induction was completely obliterated by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. The HO-1 SBE3 mediates HO-1 gene induction by IL-6 mainly via activation of the Jak/STAT pathway.

The effect of moderate-intensity exercise on the expression of HO-1 mRNA and activity of HO in cardiac and vascular smooth muscle of spontaneously hypertensive rats.

PubMed

Ren, Cailing; Qi, Jie; Li, Wanwei; Zhang, Jun

2016-04-01

The objective of this study was to observe the effects of moderate-intensity training on the activity of heme oxygenase (HO) and expression of HO-1 mRNA in the aorta and the cardiac muscle of spontaneously hypertensive rats (SHRs). After 9 weeks of swimming exercise, the activity of HO and expression of HO-1 mRNA in the SHRs were measured. The resting blood pressure in the exercise group was increased by 1.7% (P > 0.05), whereas it was significantly elevated by 10.3% (P < 0.01) in the SHR rats. Compared with animals in the control and sedentary groups, the expression level of HO-1 mRNA of aorta and cardiac muscle in the exercise group was significantly enhanced (P < 0.01). The HO activity and the content of plasma carbon monoxide (CO) in the sedentary group were dramatically decreased (P < 0.05 and P < 0.01, respectively) compared with the control group. HO activity and content of plasma CO in the exercise group were significantly higher compared with those in the sedentary group (P < 0.05 and P < 0.01, respectively). The HO/CO metabolic pathway might be involved in the regulation of blood pressure of the SHR models.

Heterogeneous reaction of HO2 with airborne TiO2 particles and its implication for climate change mitigation strategies

NASA Astrophysics Data System (ADS)

Moon, Daniel R.; Taverna, Giorgio S.; Anduix-Canto, Clara; Ingham, Trevor; Chipperfield, Martyn P.; Seakins, Paul W.; Baeza-Romero, Maria-Teresa; Heard, Dwayne E.

2018-01-01

One geoengineering mitigation strategy for global temperature rises resulting from the increased concentrations of greenhouse gases is to inject particles into the stratosphere to scatter solar radiation back to space, with TiO2 particles emerging as a possible candidate. Uptake coefficients of HO2, γ(HO2), onto sub-micrometre TiO2 particles were measured at room temperature and different relative humidities (RHs) using an atmospheric pressure aerosol flow tube coupled to a sensitive HO2 detector. Values of γ(HO2) increased from 0.021 ± 0.001 to 0.036 ± 0.007 as the RH was increased from 11 to 66 %, and the increase in γ(HO2) correlated with the number of monolayers of water surrounding the TiO2 particles. The impact of the uptake of HO2 onto TiO2 particles on stratospheric concentrations of HO2 and O3 was simulated using the TOMCAT three-dimensional chemical transport model. The model showed that, when injecting the amount of TiO2 required to achieve the same cooling effect as the Mt Pinatubo eruption, heterogeneous reactions between HO2 and TiO2 would have a negligible effect on stratospheric concentrations of HO2 and O3.

The cytoprotective enzyme heme oxygenase-1 suppresses Ebola virus replication.

PubMed

Hill-Batorski, Lindsay; Halfmann, Peter; Neumann, Gabriele; Kawaoka, Yoshihiro

2013-12-01

Ebola virus (EBOV) is the causative agent of a severe hemorrhagic fever in humans with reported case fatality rates as high as 90%. There are currently no licensed vaccines or antiviral therapeutics to combat EBOV infections. Heme oxygenase-1 (HO-1), an enzyme that catalyzes the rate-limiting step in heme degradation, has antioxidative properties and protects cells from various stresses. Activated HO-1 was recently shown to have antiviral activity, potently inhibiting the replication of viruses such as hepatitis C virus and human immunodeficiency virus. However, the effect of HO-1 activation on EBOV replication remains unknown. To determine whether the upregulation of HO-1 attenuates EBOV replication, we treated cells with cobalt protoporphyrin (CoPP), a selective HO-1 inducer, and assessed its effects on EBOV replication. We found that CoPP treatment, pre- and postinfection, significantly suppressed EBOV replication in a manner dependent upon HO-1 upregulation and activity. In addition, stable overexpression of HO-1 significantly attenuated EBOV growth. Although the exact mechanism behind the antiviral properties of HO-1 remains to be elucidated, our data show that HO-1 upregulation does not attenuate EBOV entry or budding but specifically targets EBOV transcription/replication. Therefore, modulation of the cellular enzyme HO-1 may represent a novel therapeutic strategy against EBOV infection.

A 15 W 1152 nm Raman fiber laser with 6 nm spectral width for Ho3+-doped crystal's pumping source

NASA Astrophysics Data System (ADS)

Chen, Xiuyan; Jiang, Huawei

2016-12-01

A 11.5 W 1152 nm Raman fiber laser with 6 nm spectral width was demonstrated based on the resonator constructed with one fiber loop mirror and one fiber Bragg grating. By mans of experimental measurement and theoretical calculation, the reflectivity of the fiber loop mirror was confirmed as 0.93. The Yb3+-doped 1090 nm fiber length was about 5 m. When the maximum pumping power of 976 nm laser was 54.8 W, 32.2 W 1090 nm laser was obtained and the optical to optical conversion efficiency from 1090 nm to 1152 nm light was 48%. Finally, the 1152 nm Raman fiber laser was used for pumping Ho3+:LLF crystal, and the 1194 nm fluorescence emission peak was detected for the first time.

Is the 'Bromine Explosion' generated from the reaction BrO HO2 alone?

NASA Astrophysics Data System (ADS)

Behnke, Wolfgang; Zetzsch, Cornelius

2010-05-01

We observed bromine explosions (a fast production of atomic Br and Cl under tropospheric conditions) in various smog chamber experiments in Teflon bags at room temperature at a relative humidity of about 80% in the presence of NaCl/NaBr-aerosol, simulated sunlight and ozone (200 - 400 ppb). Time profiles of ozone and hydrocarbons (HCs: n-butane, 2,2-dimethylbutane, tetramethylbutane and toluene, initially about 2 ppb each) were monitored to determine concentrations and source strengths of OH radicals, atomic Cl and Br and the corresponding time profiles of BrCl and Br2 as their photolytic precursors. The number and size of aerosols are measured as well as their chemical composition (Br-, Cl- and oxalic acid). Full records of raw data from the smog chamber runs are available at www.eurochamp.org for potential users. Chemical box model calculations deliver concentrations of various intermediates, such as aldehydes, HO2 and RO2 radicals and the inorganic halogen compounds ClO, BrO, HOCl and HOBr, where HOBr from O3 + Br- => BrO- + O2 in the aqueous/adsorbed phase induces the following gas-phase/ heterogeneous chain reaction Br + O3 => BrO + O2(1) BrO + HO2 => HOBr + O2(2a) HOBr + (Aerosol) => HOBrad(3) Surface-adsorbed HOBr reacts with Br- or Cl- to produce Br2 or BrCl, both of which are released and photolysed. Formation of Br2 should prevail up to Cl-/Br- -ratios of about 104 (Fickert, S., J.W. Adams, J.N. Crowley, J. Geophys. Res., D104, 23719-23727, 1999). A maximum of this ratio is reached about 30 minutes after the beginning and decreases during the next hours - probably by reaction of Br2 with oxalate and absorption of HBr, formed from the reaction of Br with aldehydes. Parallel to chain reaction (1)-(3) a chain reaction replacing Br by Cl seems possible but can not be realized, since the main sink of atomic Cl is its reaction with hydrocarbons - leading to chain termination - in contrast to atomic Br (ratio of rates: kCl[O3]/kCl[HC] ~ 0.1; kBr[O3]/kBr[toluene] ~ 100). Formation of aldehydes (R-CHO) interferes with the chain reaction (1) - (3) markedly, since kBr[O3] ≈kBr[R-CHO]. The chain reaction is limited by availability of ozone (degradation of HCs by atomic Cl stops completely with vanishing ozone), of HO2 (HCs are required to form HO2) and of aerosol. The central question is: will sufficient HO2 be formed from degradation of HCs to explain the magnitude of the formed Br2 and BrCl in our experiments? We found that the formation of HO2 should be by a factor of 2-4 larger to explain the formation of Br2 and BrCl. Which other sources for the formation of HOBr besides reaction (2a) are then available? The rate of CH3O2with BrO is 25% of that with HO2 (Enami, S.; Yamanaka, T.; Nakayama, T.; Hashimoto, S.; Kawasaki, M.; Shallcross, D.E.; Nakano, Y.; Ishiwata, T., J. Phys. Chem. A, 11, 3342 - 3348, 2007), suggesting that other RO2 radicals must contribute. In our model calculations we use this rate constant for all RO2 radicals to obtain reasonable agreement between the produced HOBr and the formed BrCl and Br2 necessary for our experimental degradation results. So reaction scheme (1) - (3) should be completed by: BrO + RO2 => HOBr + products (2b) The German Science Foundation (DFG) supported this research in unit 783 (HALOPROC).

Oxidative stress induces vascular heme oxygenase-1 expression in ovariectomized rats.

PubMed

Lee, Yen-Mei; Cheng, Pao-Yun; Hong, Su-Fen; Chen, Shu-Ying; Lam, Kwok-Keung; Sheu, Joen-Rong; Yen, Mao-Hsiung

2005-07-01

Heme oxygenase-1 (HO-1), an inducible stress protein, has been implicated in cytoprotection against oxidative stress in vitro and in vivo. Estrogens also have antioxidant effects. This study investigated the time course of HO-1 and inducible nitric oxide synthase (iNOS) expression in the aortas of ovariectomized rats, and the regulatory relationship between the NO/NOS and the carbon monoxide/HO systems. HO-1 and iNOS protein expression was induced by ovariectomy (Ovx) and was extremely high 2-6 weeks after Ovx compared with the sham-operated group. Expression of the constitutive enzymes HO-2 and endothelial NOS did not differ significantly between sham-operated and Ovx rats. 17beta-Estradiol (E(2)) replacement reversed these changes in rats after Ovx. Long-term treatment with the antioxidant tempol significantly inhibited HO-1 and iNOS expression. The iNOS inhibitor aminoguanidine significantly suppressed the induction of HO-1. Oxidized glutathione in the hearts of Ovx rats increased gradually, with significant elevation at 3-6 weeks after Ovx compared with the sham-operated group, whereas plasma levels of NO metabolites were significantly reduced 4-6 weeks after Ovx. Treatment with the HO inhibitor zinc protoporphyrin IX blocked HO-1 induction, but significantly increased the plasma levels of NO metabolites. In conclusion, HO-1 is induced by oxidative stress resulting from E(2) depletion. The NO/iNOS system contributes to the induction of HO-1, which may subsequently suppress iNOS activity to modulate vasculoprotective effects after menopause.

Lung endothelial HO-1 targeting in vivo using lentiviral miRNA regulates apoptosis and autophagy during oxidant injury

PubMed Central

Zhang, Yi; Jiang, Ge; Sauler, Maor; Lee, Patty J.

2013-01-01

The lung endothelium is a major target for inflammatory and oxidative stress. Heme oxygenase-1 (HO-1) induction is a crucial defense mechanism during oxidant challenges, such as hyperoxia. The role of lung endothelial HO-1during hyperoxia in vivo is not well defined. We engineered lentiviral vectors with microRNA (miRNA) sequences controlled by vascular endothelium cadherin (VE-cad) to study the specific role of lung endothelial HO-1. Wild-type (WT) murine lung endothelial cells (MLECs) or WT mice were treated with lentivirus and exposed to hyperoxia (95% oxygen). We detected HO-1 knockdown (∼55%) specifically in the lung endothelium. MLECs and lungs showed approximately a 2-fold increase in apoptosis and ROS generation after HO-1 silencing. We also demonstrate for the first time that silencing endothelial HO-1 has the same effect on lung injury and survival as silencing HO-1 in multiple lung cell types and that HO-1 regulates caspase 3 activation and autophagy in endothelium during hyperoxia. These studies demonstrate the utility of endothelial-targeted gene silencing in vivo using lentiviral miRNA constructs to assess gene function and that endothelial HO-1 is an important determinant of survival during hyperoxia.—Zhang, Y., Jiang, G., Sauler, M., Lee, P. J. Lung endothelial HO-1 targeting in vivo using lentiviral miRNA regulates apoptosis and autophagy during oxidant injury. PMID:23771928

Synthesis and capacitance properties of N-doped porous carbon/NiO nanosheet composites using coal-based polyaniline as carbon and nitrogen source

NASA Astrophysics Data System (ADS)

Wang, Xiaoqin; Li, Qiaoqin; Zhang, Yong; Yang, Yufei; Cao, Zhi; Xiong, Shanxin

2018-06-01

A novel synthesis approach of N-doped porous carbon (NPC)/NiO composites possessing some honeycomb-shaped nanoporous carbon and plentiful NiO nanosheets is exploited. First NPC/Ni composites are achieved with NPC yield of 52.9% through a catalytic pyrolysis method, using coal-based polyaniline particles prepared by an in-situ polymerization method as a carbon and nitrogen source, and nickel particles as a catalyst, respectively. Next NPC/NiO composites are achieved unexpectedly with plentiful NiO nanosheets and N content of 1.00 wt% after a liquid oxidation process. In NPC/NiO composites, porous carbon mainly presents in the amorphous state, while the incorporated nitrogen mainly presents in the form of pyrrolic N (92.9 at.%) and oxidized N (7.1 at.%). Plentiful NiO nanosheets are embedded in the pores or on the NPC surface. 33.3 at.% Ni2O3 components exist in the surface of NiO nanosheets. NPC/NiO composites possess not only rich micropores, but also significant mesopores and nanoscale macropores. The BET specific surface area, BET average pore width and BJH adsorption average pore diameter are 627.5 m2/g, 2.0 nm and 5.1 nm, respectively. NPC/NiO composites demonstrate a high specific capacitance of 404.1 F/g at 1 A/g, and a good cycling stability maintaining high specific capacitance of 212.4 F/g (84.3% of the initial capacitance) at 5 A/g after 5000 cycles of charge and discharge, attributed to some honeycomb-shaped nanopores of carbon and large specific surface area of NiO nanosheets, and the synergistic effects between electric double-layer capacitance of NPC and pseudocapacitance of NiO. This study may provide a novel approach for the value-added applications of low-rank coal.

The effects of increased heme oxygenase-1 on the lymphoproliferative response in dogs with visceral leishmaniasis.

PubMed

Almeida, Breno Fernando Martins de; Silva, Kathlenn Liezbeth Oliveira; Chiku, Vanessa Marim; Leal, Aline Aparecida Correa; Venturin, Gabriela Lovizutto; Narciso, Luis Gustavo; Fink, Maria Fernanda Cereijido Bersni; Eugênio, Flavia de Rezende; Santos, Paulo Sergio Patto Dos; Ciarlini, Paulo Cesar; Lima, Valéria Marçal Felix de

2017-05-01

Canine visceral leishmaniasis (CVL) is known to affect the cellular immunity of infected dogs, through impairing lymphoproliferation and microbicidal mechanisms. This study examined heme oxygenase-1 (HO-1) and its metabolites, oxidative stress and IL-10 levels in CVL and investigated correlations between these parameters. Additionally, the effects of HO-1 inhibition on the lymphoproliferative response and cytokine production in lymph node cells (LNCs) from infected dogs were evaluated. Forty-four dogs, 24 controls and 20 dogs with CVL were selected. Plasma and splenic levels of HO-1, haptoglobin, soluble CD163 receptor, ferritin and IL-10 were determined using capture ELISA. The HO-1 levels and relative gene expression in peripheral blood and bone marrow mononuclear cells were also determined. LNCs proliferation was evaluated with an HO-1 activator and with an HO-1 inhibitor, in the presence of the Leishmania infantum soluble antigen (SAgL), using flow cytometry. HO-1, IL-2, IFN-gamma and IL-10 were also determined in these cultures using capture ELISA. Infected dogs presented oxidative stress and increased HO-1 levels and relative gene expression, with correlation between oxidative stress and HO-1. The substances from heme metabolism and IL-10 were also elevated in the plasma and spleens of infected dogs. IL-10 and HO-1 levels were positively correlated with one another. Inhibition of HO-1 increased LNCs proliferation and decreased IL-10 and IL-2 production in the presence of SAgL. The increased HO-1 metabolism observed in CVL is probably associated with oxidative stress and increased IL-10, which could be one of the mechanisms responsible for inhibition of the lymphoproliferative response in sick dogs. Copyright © 2016 Elsevier GmbH. All rights reserved.

Characterization of docosahexaenoic acid (DHA)-induced heme oxygenase-1 (HO-1) expression in human cancer cells: the importance of enhanced BTB and CNC homology 1 (Bach1) degradation.

PubMed

Wang, Shuai; Hannafon, Bethany N; Wolf, Roman F; Zhou, Jundong; Avery, Jori E; Wu, Jinchang; Lind, Stuart E; Ding, Wei-Qun

2014-05-01

The effect of docosahexaenoic acid (DHA) on heme oxygenase-1 (HO-1) expression in cancer cells has never been characterized. This study examines DHA-induced HO-1 expression in human cancer cell model systems. DHA enhanced HO-1 gene expression in a time- and concentration-dependent manner, with maximal induction at 21 h of treatment. This induction of HO-1 expression was confirmed in vivo using a xenograft nude mouse model fed a fish-oil-enriched diet. The increase in HO-1 gene transcription induced by DHA was significantly attenuated by the antioxidant N-acetyl cysteine, suggesting the involvement of oxidative stress. This was supported by direct measurement of lipid peroxide levels after DHA treatment. Using a human HO-1 gene promoter reporter construct, we identified two antioxidant response elements (AREs) that mediate the DHA-induced increase in HO-1 gene transcription. Knockdown of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression compromised the DHA-induced increase in HO-1 gene transcription, indicating the importance of the Nrf2 pathway in this event. However, the nuclear protein levels of Nrf2 remained unchanged upon DHA treatment. Further studies demonstrated that DHA reduces nuclear Bach1 protein expression by promoting its degradation and attenuates Bach1 binding to the AREs in the HO-1 gene promoter. In contrast, DHA enhanced Nrf2 binding to the AREs without affecting nuclear Nrf2 expression levels, indicating a new cellular mechanism that mediates DHA's induction of HO-1 gene transcription. To our knowledge, this is the first characterization of DHA-induced HO-1 expression in human malignant cells. Copyright © 2014 Elsevier Inc. All rights reserved.

Haem oxygenase delays programmed cell death in wheat aleurone layers by modulation of hydrogen peroxide metabolism

PubMed Central

Wu, Mingzhu; Huang, Jingjing; Xu, Sheng; Ling, Tengfang; Xie, Yanjie; Shen, Wenbiao

2011-01-01

Haem oxygenase-1 (HO-1) confers protection against a variety of oxidant-induced cell and tissue injury in animals and plants. In this report, it is confirmed that programmed cell death (PCD) in wheat aleurone layers is stimulated by GA and prevented by ABA. Meanwhile, HO activity and HO-1 protein expression exhibited lower levels in GA-treated layers, whereas the hydrogen peroxide (H2O2) content was apparently increased. The pharmacology approach illustrated that scavenging or accumulating H2O2 either delayed or accelerated GA-induced PCD. Furthermore, pretreatment with the HO-1 specific inhibitor, zinc protoporphyrin IX (ZnPPIX), before exposure to GA, not only decreased HO activity but also accelerated GA-induced PCD significantly. The application of the HO-1 inducer, haematin, and the enzymatic reaction product of HO, carbon monoxide (CO) aqueous solution, both of which brought about a noticeable induction of HO expression, substantially prevented GA-induced PCD. These effects were reversed when ZnPPIX was added, suggesting that HO in vivo played a role in delaying PCD. Meanwhile, catalase (CAT) and ascorbate peroxidase (APX) activities or transcripts were enhanced by haematin, CO, or bilirubin (BR), the catalytic by-product of HO. This enhancement resulted in a decrease in H2O2 production and a delay in PCD. In addition, the antioxidants butylated hydroxytoluene (BHT), dithiothreitol (DTT), and ascorbic acid (AsA) were able not only to delay PCD but also to mimic the effects of haematin and CO on HO up-regulation. Overall, the above results suggested that up-regulation of HO expression delays PCD through the down-regulation of H2O2 production. PMID:20797999

Regulation of human heme oxygenase in endothelial cells by using sense and antisense retroviral constructs

PubMed Central

Quan, Shuo; Yang, Liming; Abraham, Nader G.; Kappas, Attallah

2001-01-01

Our objective was to determine whether overexpression and underexpression of human heme oxygenase (HHO)-1 could be controlled on a long-term basis by introduction of the HO-1 gene in sense (S) and antisense (AS) orientation with an appropriate vector into endothelial cells. Retroviral vector (LXSN) containing viral long terminal repeat promoter-driven human HO-1 S (LSN-HHO-1) and LXSN vectors containing HHO-1 promoter (HOP)-controlled HHO-1 S and AS (LSN-HOP-HHO-1 and LSN-HOP-HHO-1-AS) sequences were constructed and used to transfect rat lung microvessel endothelial cells (RLMV cells) and human dermal microvessel endothelial cells (HMEC-1 cells). RLMV cells transduced with HHO-1 S expressed human HO-1 mRNA and HO-1 protein associated with elevation in total HO activity compared with nontransduced cells. Vector-mediated expression of HHO-1 S or AS under control of HOP resulted in effective production of HO-1 or blocked induction of endogenous human HO-1 in HMEC-1 cells, respectively. Overexpression of HO-1 AS was associated with a long-term decrease (45%) of endogenous HO-1 protein and an increase (167%) in unmetabolized exogenous heme in HMEC-1 cells. Carbon monoxide (CO) production in HO-1 S- or AS-transduced HMEC-1 cells after heme treatment was increased (159%) or decreased (50%), respectively, compared with nontransduced cells. HO-2 protein levels did not change. These findings demonstrate that HHO-1 S and AS retroviral constructs are functional in enhancing and reducing HO activity, respectively, and thus can be used to regulate cellular heme levels, the activity of heme-dependent enzymes, and the rate of heme catabolism to CO and bilirubin. PMID:11593038

Regulation of human heme oxygenase in endothelial cells by using sense and antisense retroviral constructs.

PubMed

Quan, S; Yang, L; Abraham, N G; Kappas, A

2001-10-09

Our objective was to determine whether overexpression and underexpression of human heme oxygenase (HHO)-1 could be controlled on a long-term basis by introduction of the HO-1 gene in sense (S) and antisense (AS) orientation with an appropriate vector into endothelial cells. Retroviral vector (LXSN) containing viral long terminal repeat promoter-driven human HO-1 S (LSN-HHO-1) and LXSN vectors containing HHO-1 promoter (HOP)-controlled HHO-1 S and AS (LSN-HOP-HHO-1 and LSN-HOP-HHO-1-AS) sequences were constructed and used to transfect rat lung microvessel endothelial cells (RLMV cells) and human dermal microvessel endothelial cells (HMEC-1 cells). RLMV cells transduced with HHO-1 S expressed human HO-1 mRNA and HO-1 protein associated with elevation in total HO activity compared with nontransduced cells. Vector-mediated expression of HHO-1 S or AS under control of HOP resulted in effective production of HO-1 or blocked induction of endogenous human HO-1 in HMEC-1 cells, respectively. Overexpression of HO-1 AS was associated with a long-term decrease (45%) of endogenous HO-1 protein and an increase (167%) in unmetabolized exogenous heme in HMEC-1 cells. Carbon monoxide (CO) production in HO-1 S- or AS-transduced HMEC-1 cells after heme treatment was increased (159%) or decreased (50%), respectively, compared with nontransduced cells. HO-2 protein levels did not change. These findings demonstrate that HHO-1 S and AS retroviral constructs are functional in enhancing and reducing HO activity, respectively, and thus can be used to regulate cellular heme levels, the activity of heme-dependent enzymes, and the rate of heme catabolism to CO and bilirubin.

Rapid induction of heme oxygenase 1 mRNA and protein by hyperthermia in rat brain: heme oxygenase 2 is not a heat shock protein.

PubMed Central

Ewing, J F; Maines, M D

1991-01-01

Catalytic activity of heme oxygenase (heme, hydrogen-donor:oxygen oxidoreductase, EC 1.14.99.3) isozymes, HO-1 and HO-2, permits production of physiologic isomers of bile pigments. In turn, bile pigments biliverdin and bilirubin are effective antioxidants in biological systems. In the rat brain we have identified only the HO-1 isozyme of heme oxygenase as a heat shock protein and defined hyperthermia as a stimulus that causes an increase in brain HO-1 protein. Exposure of male rats to 42 degrees C for 20 min caused a rapid and marked increase in brain 1.8-kilobase HO-1 mRNA. Specifically, a 33-fold increase in brain HO-1 mRNA was observed within 1 h and sustained for at least 6 h posttreatment. In contrast, the two HO-2 homologous transcripts (1.3 and 1.9 kilobases) did not respond to heat shock; neither the ratio nor the level of the two messages differed from that of the control when measured either at 1, 6, or 24 h after hyperthermia. The induction of a 1.8-kilobase HO-1 mRNA resulted in a pronounced increase in HO-1 protein 6 h after hyperthermia, as detected by both Western immunoblot and RIA. Immunocytochemistry of rat brain showed discrete localization of HO-1-like protein only in neurons of select brain regions. Six hours after heat shock, an intense increase in HO-1-like protein was observed in both Purkinje cells of the cerebellum and epithelial cells lining the cerebral aqueduct of the brain. We suggest that the increase in HO-1 protein, hence increased capacity to form bile pigments, represents a neuronal defense mechanism against heat shock stress. Images PMID:2052613

Consistency of the Health of the Nation Outcome Scales (HoNOS) at inpatient-to-community transition.

PubMed

Luo, Wei; Harvey, Richard; Tran, Truyen; Phung, Dinh; Venkatesh, Svetha; Connor, Jason P

2016-04-27

The Health of the Nation Outcome Scales (HoNOS) are mandated outcome-measures in many mental-health jurisdictions. When HoNOS are used in different care settings, it is important to assess if setting specific bias exists. This article examines the consistency of HoNOS in a sample of psychiatric patients transitioned from acute inpatient care and community centres. A regional mental health service with both acute and community facilities. 111 psychiatric patients were transferred from inpatient care to community care from 2012 to 2014. Their HoNOS scores were extracted from a clinical database; Each inpatient-discharge assessment was followed by a community-intake assessment, with the median period between assessments being 4 days (range 0-14). Assessor experience and professional background were recorded. The difference of HoNOS at inpatient-discharge and community-intake were assessed with Pearson correlation, Cohen's κ and effect size. Inpatient-discharge HoNOS was on average lower than community-intake HoNOS. The average HoNOS was 8.05 at discharge (median 7, range 1-22), and 12.16 at intake (median 12, range 1-25), an average increase of 4.11 (SD 6.97). Pearson correlation between two total scores was 0.073 (95% CI -0.095 to 0.238) and Cohen's κ was 0.02 (95% CI -0.02 to 0.06). Differences did not appear to depend on assessor experience or professional background. Systematic change in the HoNOS occurs at inpatient-to-community transition. Some caution should be exercised in making direct comparisons between inpatient HoNOS and community HoNOS scores. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Colloidal nickel/gallium nanoalloys obtained from organometallic precursors in conventional organic solvents and in ionic liquids: noble-metal-free alkyne semihydrogenation catalysts

NASA Astrophysics Data System (ADS)

Schütte, Kai; Doddi, Adinarayana; Kroll, Clarissa; Meyer, Hajo; Wiktor, Christian; Gemel, Christian; van Tendeloo, Gustaaf; Fischer, Roland A.; Janiak, Christoph

2014-04-01

Efforts to replace noble-metal catalysts by low-cost alternatives are of constant interest. The organometallic, non-aqueous wet-chemical synthesis of various hitherto unknown nanocrystalline Ni/Ga intermetallic materials and the use of NiGa for the selective semihydrogenation of alkynes to alkenes are reported. Thermal co-hydrogenolysis of the all-hydrocarbon precursors [Ni(COD)2] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in high-boiling organic solvents mesitylene and n-decane in molar ratios of 1 : 1, 2 : 3 and 3 : 1 yields the nano-crystalline powder materials of the over-all compositions NiGa, Ni2Ga3 and Ni3Ga, respectively. Microwave induced co-pyrolysis of the same precursors without additional hydrogen in the ionic liquid [BMIm][BF4] (BMIm = 1-butyl-3-methyl-imidazolium) selectively yields the intermetallic phases NiGa and Ni3Ga from the respective 1 : 1 and 3 : 1 molar ratios of the precursors. The obtained materials are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), IR, powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The single-source precursor [Ni(GaCp*)(PMe3)3] with a fixed Ni : Ga stoichiometry of 1 : 1 was employed as well. In comparison with the co-hydrogenolytic dual precursor source approach it turned out to be less practical due to inefficient nickel incorporation caused by the parasitic formation of stable [Ni(PMe3)4]. The use of ionic liquid [BMIm][BF4] as a non-conventional solvent to control the reaction and stabilize the nanoparticles proved to be particularly advantageous and stable colloids of the nanoalloys NiGa and Ni3Ga were obtained. A phase-selective Ni/Ga colloid synthesis in conventional solvents and in the presence of surfactants such as hexadecylamine (HDA) was not feasible due to the undesired reactivity of HDA with GaCp* leading to inefficient gallium incorporation. Recyclable NiGa nanoparticles selectively semihydrogenate 1-octyne and diphenylacetylene (tolan) to 1-octene and diphenylethylene, respectively, with a yield of about 90% and selectivities of up to 94 and 87%. Ni-NPs yield alkanes with a selectivity of 97 or 78%, respectively, under the same conditions.Efforts to replace noble-metal catalysts by low-cost alternatives are of constant interest. The organometallic, non-aqueous wet-chemical synthesis of various hitherto unknown nanocrystalline Ni/Ga intermetallic materials and the use of NiGa for the selective semihydrogenation of alkynes to alkenes are reported. Thermal co-hydrogenolysis of the all-hydrocarbon precursors [Ni(COD)2] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in high-boiling organic solvents mesitylene and n-decane in molar ratios of 1 : 1, 2 : 3 and 3 : 1 yields the nano-crystalline powder materials of the over-all compositions NiGa, Ni2Ga3 and Ni3Ga, respectively. Microwave induced co-pyrolysis of the same precursors without additional hydrogen in the ionic liquid [BMIm][BF4] (BMIm = 1-butyl-3-methyl-imidazolium) selectively yields the intermetallic phases NiGa and Ni3Ga from the respective 1 : 1 and 3 : 1 molar ratios of the precursors. The obtained materials are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), IR, powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The single-source precursor [Ni(GaCp*)(PMe3)3] with a fixed Ni : Ga stoichiometry of 1 : 1 was employed as well. In comparison with the co-hydrogenolytic dual precursor source approach it turned out to be less practical due to inefficient nickel incorporation caused by the parasitic formation of stable [Ni(PMe3)4]. The use of ionic liquid [BMIm][BF4] as a non-conventional solvent to control the reaction and stabilize the nanoparticles proved to be particularly advantageous and stable colloids of the nanoalloys NiGa and Ni3Ga were obtained. A phase-selective Ni/Ga colloid synthesis in conventional solvents and in the presence of surfactants such as hexadecylamine (HDA) was not feasible due to the undesired reactivity of HDA with GaCp* leading to inefficient gallium incorporation. Recyclable NiGa nanoparticles selectively semihydrogenate 1-octyne and diphenylacetylene (tolan) to 1-octene and diphenylethylene, respectively, with a yield of about 90% and selectivities of up to 94 and 87%. Ni-NPs yield alkanes with a selectivity of 97 or 78%, respectively, under the same conditions. Electronic supplementary information (ESI) available: Ni-Ga phase diagrams, EDX (XPS) of NP1-NP8, table of Ni : Ga ratios, TG of Ni-Ga SSPs, analysis of NP4, dec. of [Ni(GaCp*)3(PCy3)] with characterization, local resolution EDX of NP3-IL, Ni-NP characterization from Ni(COD)2 and details of (semi-)hydrogenation catalysis. See DOI: 10.1039/c4nr00111g

Effect of Wood Aging on Wine Mineral Composition and 87Sr/86Sr Isotopic Ratio.

PubMed

Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

2017-06-14

The evolution of mineral composition and wine strontium isotopic ratio 87 Sr/ 86 Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87 Sr/ 86 Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87 Sr/ 86 Sr, not precluding the use of this parameter for wine traceability purposes.

Clinical Applications of Wavefront Refraction

PubMed Central

Bruce, Adrian S.; Catania, Louis J.

2014-01-01

ABSTRACT Purpose To determine normative reference ranges for higher-order wavefront error (HO-WFE), compare these values with those in common ocular pathologies, and evaluate treatments. Methods A review of 17 major studies on HO-WFE was made, involving data for a total of 31,605 subjects. The upper limit of the 95% confidence interval (CI) for HO-WFE was calculated from the most comprehensive of these studies using normal healthy patients aged 20 to 80 years. There were no studies identified using the natural pupil size for subjects, and for this reason, the HO-WFE was tabulated for pupil diameters of 3 to 7 mm. Effects of keratoconus, pterygium, cataract, and dry eye on HO-WFE were reviewed and treatment efficacy was considered. Results The calculated upper limit of the 95% CI for HO-WFE in a healthy normal 35-year-old patient with a mesopic pupil diameter of 6 mm would be 0.471 μm (471 nm) root-mean-square or less. Although the normal HO-WFE increases with age for a given pupil size, it is not yet completely clear how the concurrent influence of age-related pupillary miosis affects these findings. Abnormal ocular conditions such as keratoconus can induce a large HO-WFE, often in excess of 3.0 μm, particularly attributed to coma. For pterygium or cortical cataract, a combination of coma and trefoil was more commonly induced. Nuclear cataract can induce a negative spherical HO-WFE, usually in excess of 1.0 μm. Conclusions The upper limit of the 95% CI for HO-WFE root-mean-square is about 0.5 μm with normal physiological pupil sizes. With ocular pathologies, HO-WFE can be in excess of 1.0 μm, although many devices and therapeutic and surgical treatments are reported to be highly effective at minimizing HO-WFE. More accurate normative reference ranges for HO-WFE will require future studies using the subjects’ natural pupil size. PMID:25216319

Upregulation of heme oxygenase-1 gene by turpentine oil-induced localized inflammation: involvement of interleukin-6.

PubMed

Tron, Kyrylo; Novosyadlyy, Ruslan; Dudas, Jozsef; Samoylenko, Anatoly; Kietzmann, Thomas; Ramadori, Giuliano

2005-03-01

Heme oxygenase-1 (HO-1) is the inducible isoform of an enzyme family responsible for heme degradation and was suggested to be involved in the acute phase response in the liver. However, the mechanisms of the HO-1 regulation under inflammatory conditions are poorly understood. Therefore, the purpose of the current work was to study the expression of HO-1 in the liver and other organs of rats with a localized inflammation after intramuscular injection of turpentine oil (TO). Since interleukin-6 (IL-6) is known to be a principal mediator of inflammation, the levels of this cytokine were also estimated in the animal model used. HO-1 and IL-6 expression was evaluated by Northern blot, in situ hybridization, Western blot, immunohistochemistry and enzyme-linked immunosorbent assay. In the liver and injured muscle, the HO-1 mRNA levels were dramatically increased 4-6 h after TO administration. HO-1 protein levels in the liver were elevated starting from 6-12 h after the treatment. In other internal organs such as the heart, kidney and large intestine, only a slight induction of HO-1 mRNA was observed. IL-6-specific transcripts appeared only in the injured muscle and were in accordance with serum levels of IL-6. In turn, temporal expression of IL-6 in the muscle and circulatory IL-6 levels correlated well with HO-1 expression in the liver and injured muscle. In the liver of control rats HO-1 protein was detected in Kupffer cells, while in TO-injected rats also hepatocytes became strongly HO-1 positive. Conversely, in the injured muscle, HO-1 immunoreactivity was attributed only to macrophages. Our data demonstrate that during localized inflammation HO-1 expression was rapidly and strongly induced in macrophages of injured muscle and in hepatocytes, and IL-6 derived from injured muscle seems to be responsible for the HO-1 induction in the liver.

Lipoxin A4-Induced Heme Oxygenase-1 Protects Cardiomyocytes against Hypoxia/Reoxygenation Injury via p38 MAPK Activation and Nrf2/ARE Complex

PubMed Central

Chen, Xiao-Qing; Wu, Sheng-Hua; Zhou, Yu; Tang, Yan-Rong

2013-01-01

Objective To investigate whether lipoxin A4 (LXA4) increases expression of heme oxygenase-1(HO-1) in cardiomyocytes, whether LXA4-induced HO-1 protects cardiomyocytes against hypoxia/reoxygenation (H/R) injury, and what are the mechanisms involved in the LXA4-induced HO-1 induction. Methods Rat cardiomyocytes were exposed to H/R injury with or without preincubation with LXA4 or HO-1 inhibitor ZnPP-IX or various signal molecule inhibitors. Expressions of HO-1 protein and mRNA were analyzed by using Western blot and RT-PCR respectively. Activity of nuclear factor E2-related factor 2 (Nrf2) binding to the HO-1 E1 enhancer was assessed by chromatin immunoprecipitation. Nrf2 binding to the HO-1 antioxidant responsive element (ARE) were measured by using electrophoretic mobility shift assay. Results Pretreatment of the cells undergoing H/R lesion with LXA4 significantly reduced the lactate dehydrogenase and creatine kinase productions, increased the cell viability, and increased the expressions of HO-1 protein and mRNA and HO-1 promoter activity. HO-1 inhibition abolished the protective role of LXA4 on the cells undergoing H/R lesion. LXA4 increased p38 mitogen-activated protein kinase (p38 MAPK) activation, nuclear translocation of Nrf2, Nrf2 binding to the HO-1 ARE and E1 enhancer in cardiomyocytes with or without H/R exposure. Conclusion The protection role of LXA4 against H/R injury of cardiomyocytes is related to upregulation of HO-1, via activation of p38 MAPK pathway and nuclear translocation of Nrf2 and Nrf2 binding to the HO-1 ARE and E1 enhancer, but not via activation of phosphatidyinositol-3-kinase or extracellular signal-regulated kinase pathway. PMID:23826208

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

Kwon, Soon Won; Sohn, Eun Jeong; Kim, Dae Won

Highlights: {yields} Recombinant PEP-1 heme oxygenase-1 expression vector was constructed and overexpressed. {yields} We investigated transduction efficiency of PEP-1-HO-1 protein in Raw 264.7 cells. {yields} PEP-1-HO-1 was efficiently transduced into Raw 264.7 cells in a dose and time dependent manner. {yields} PEP-1-HO-1 exerted anti-inflammatory activity in Raw 264.7 cells and in a mice edema model. {yields} PEP-1-HO-1 could be used as a therapeutic drug against inflammatory diseases. -- Abstract: Heme oxygenase-1 (HO-1), which catalyzes the degradation of free heme to biliverdin, carbon monoxide (CO), and free iron (Fe{sup 2+}), is up-regulated by several cellular stress and cell injuries, including inflammation,more » ischemia and hypoxia. In this study, we examined whether fusion of HO-1 with PEP-1, a protein transduction domain that is able to deliver exogenous molecules to living cells or tissues, would facilitate HO-1 delivery to target cells and tissues, and thereby effectively exert a therapeutically useful response against inflammation. Western blot analysis demonstrated that PEP-1-HO-1 fusion proteins were transduced into Raw 264.7 cells in time- and dose-dependent manners, and were stably maintained in the cells for about 60 h. In addition, fluorescence analysis revealed that only PEP-1-HO-1 fusion proteins were significantly transduced into the cytoplasm of cells, while HO-1 proteins failed to be transduced. In lipopolysaccharide (LPS)-stimulated Raw 264.7 cells and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse edema model, transduced PEP-1-HO-1 fusion proteins effectively inhibited the overexpression of pro-inflammatory mediators and cytokines. Also, histological analysis demonstrated that PEP-1-HO-1 remarkably suppressed ear edema. The results suggest that the PEP-1-HO-1 fusion protein can be used as a therapeutic molecule against reactive oxygen species-related inflammatory diseases.« less

Low heme oxygenase-1 levels in patients with systemic sclerosis are associated with an altered Toll-like receptor response: another role for CXCL4?

PubMed

van Bon, Lenny; Cossu, Marta; Scharstuhl, Alwin; Pennings, Bas W C; Vonk, Madelon C; Vreman, Hendrik J; Lafyatis, Robert L; van den Berg, Wim; Wagener, Frank A D T G; Radstake, Timothy R D J

2016-11-01

SSc is a disease characterized by inflammation and fibrosis. Heme Oxygenase-1 (HO-1) is a haem-degrading enzyme that mediates resolution of inflammation and is induced upon mediators abundantly present in SSc. We aimed to assess whether HO-1 expression/function is disturbed in SSc patients and could therefore be contributing to the ongoing inflammation. In total, 92 SSc patients and 48 healthy controls were included. By measuring total bilirubin in plasma in vivo, HO-activity was assessed. HO-1 expression levels were determined with western blot in monocytes before and after induction of HO-1 with cobalt protoporphyrin (CoPP) with or without CXCL4. Monocyte-derived dendritic cells (DCs) were stimulated with several Toll-like receptor (TLR) ligands with or without pre-stimulation with CoPP for 24 h. Cytokine levels were measured in the supernatants using the Luminex Bead Array. SSc patients have lower plasma levels of bilirubin, suggestive of an aberrant HO-1 function. We demonstrated low HO-1 expression in immune cells from SSc patients, whereas induction with CoPP was able to restore HO-1 levels in DCs from SSc patients, almost normalizing the increased TLR response observed in SSc. Co-exposure to CXCL4 completely abrogated CoPP-induced HO-1 expression, suggesting that the high CXCL4 levels present in SSc patients block the normal induction of HO-1 and its function. We demonstrate that HO activity in SSc patients is decreased and show its functional consequences. Since CXCL4 blocks the induction of HO-1 expression, neutralization of CXCL4 in SSc patients could have clinical benefits by diminishing overactivation of immune cells and other anti-inflammatory effects of HO-1. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Whole Brain Functional Connectivity Pattern Homogeneity Mapping.

PubMed

Wang, Lijie; Xu, Jinping; Wang, Chao; Wang, Jiaojian

2018-01-01

Mounting studies have demonstrated that brain functions are determined by its external functional connectivity patterns. However, how to characterize the voxel-wise similarity of whole brain functional connectivity pattern is still largely unknown. In this study, we introduced a new method called functional connectivity homogeneity (FcHo) to delineate the voxel-wise similarity of whole brain functional connectivity patterns. FcHo was defined by measuring the whole brain functional connectivity patterns similarity of a given voxel with its nearest 26 neighbors using Kendall's coefficient concordance (KCC). The robustness of this method was tested in four independent datasets selected from a large repository of MRI. Furthermore, FcHo mapping results were further validated using the nearest 18 and six neighbors and intra-subject reproducibility with each subject scanned two times. We also compared FcHo distribution patterns with local regional homogeneity (ReHo) to identify the similarity and differences of the two methods. Finally, FcHo method was used to identify the differences of whole brain functional connectivity patterns between professional Chinese chess players and novices to test its application. FcHo mapping consistently revealed that the high FcHo was mainly distributed in association cortex including parietal lobe, frontal lobe, occipital lobe and default mode network (DMN) related areas, whereas the low FcHo was mainly found in unimodal cortex including primary visual cortex, sensorimotor cortex, paracentral lobule and supplementary motor area. These results were further supported by analyses of the nearest 18 and six neighbors and intra-subject similarity. Moreover, FcHo showed both similar and different whole brain distribution patterns compared to ReHo. Finally, we demonstrated that FcHo can effectively identify the whole brain functional connectivity pattern differences between professional Chinese chess players and novices. Our findings indicated that FcHo is a reliable method to delineate the whole brain functional connectivity pattern similarity and may provide a new way to study the functional organization and to reveal neuropathological basis for brain disorders.

Heme oxygenase-1 protects endothelial cells from the toxicity of air pollutant chemicals

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

Lawal, Akeem O.; Zhang, Min; Dittmar, Michael

Diesel exhaust particles (DEPs) are a major component of diesel emissions, responsible for a large portion of their toxicity. In this study, we examined the toxic effects of DEPs on endothelial cells and the role of DEP-induced heme oxygenase-1 (HO-1) expression. Human microvascular endothelial cells (HMECs) were treated with an organic extract of DEPs from an automobile engine (A-DEP) or a forklift engine (F-DEP) for 1 and 4 h. ROS generation, cell viability, lactate dehydrogenase leakage, expression of HO-1, inflammatory genes, cell adhesion molecules and unfolded protein respone (UPR) gene were assessed. HO-1 expression and/or activity were inhibited by siRNAmore » or tin protoporphyrin (Sn PPIX) and enhanced by an expression plasmid or cobalt protoporphyrin (CoPPIX). Exposure to 25 μg/ml of A-DEP and F-DEP significantly induced ROS production, cellular toxicity and greater levels of inflammatory and cellular adhesion molecules but to a different degree. Inhibition of HO-1 enzymatic activity with SnPPIX and silencing of the HO-1 gene by siRNA enhanced DEP-induced ROS production, further decreased cell viability and increased expression of inflammatory and cell adhesion molecules. On the other hand, overexpression of the HO-1 gene by a pcDNA 3.1D/V5-HO-1 plasmid significantly mitigated ROS production, increased cell survival and decreased the expression of inflammatory genes. HO-1 expression protected HMECs from DEP-induced prooxidative and proinflammatory effects. Modulation of HO-1 expression could potentially serve as a therapeutic target in an attempt to inhibit the cardiovascular effects of ambient PM. - Highlights: • We examined the role of HO-1 expression on diesel exhaust particle (DEP) in endothelial cells. • DEPs exert cytotoxic and inflammatory effects on human microvascular endothelial cells (HMECs). • DEPs induce HO-1 expression in HMECs. • HO-1 protects against the oxidative stress induced by DEps. • HO-1 attenuates the proinflammatory effects induced by DEPs.« less

1.88 Micrometers InGaAsP Pumped, Room Temperature Ho: LuAG Laser

NASA Technical Reports Server (NTRS)

Barnes, Norman P.; Amzajerdian, Farzin; Reichle, Donald J.; Busch, George; Leisher, Paul

2009-01-01

A room temperature, directly diode pumped Ho:LuAG laser oscillated for the first time. Direct pumping of the Ho upper laser manifold maximizes efficiency, minimizes heating, and eliminates Ho:Tm energy sharing. Design and performance are presented.

Heme oxygenase-1 exacerbates early brain injury after intracerebral haemorrhage

PubMed Central

Wang, Jian; Doré, Sylvain

2008-01-01

Because heme oxygenase (HO) is the rate limiting enzyme in the degradation of the pro-oxidant hemin/heme from blood, here we investigated the contribution of the inducible HO-1 to early brain injury produced by intracerebral haemorrhage (ICH). We found that after induction of ICH, HO-1 proteins were highly detectable in the peri-ICH region predominantly in microglia/macrophages and endothelial cells. Remarkably, the injury volume was significantly smaller in HO-1 knockout (HO-1−/−) mice than in wild-type controls 24 and 72 h after ICH. Although the brain water content did not appear to be significantly different, the protection in HO-1−/− mice was associated with a marked reduction in ICH-induced leucocyte infiltration, microglia/macrophage activation and free radical levels. These data reveal a previously unrecognized role of HO-1 in early brain injury after ICH. Thus, modulation of HO-1 signalling should be assessed further in clinical settings, especially for haemorrhagic states. PMID:17525142

Adenovirus-mediated heme oxygenase-1 gene transfer into rabbit ocular tissues.

PubMed

Abraham, N G; da Silva, J L; Lavrovsky, Y; Stoltz, R A; Kappas, A; Dunn, M W; Schwartzman, M L

1995-10-01

Heme oxygenase-1 (HO-1) is a stress protein induced up to 100-fold within a few hours after exposure to oxidative stress, and it has been shown to counteract oxidative injury induced by ultraviolet light or free radicals. The current study was undertaken to determine whether the HO-1 gene can be introduced into adult rabbit ocular tissues by microinjection of a recombinant replication-deficient adenovirus human HO-1 cDNA (Adv-HHO). Human HO-1 gene was used for transfection studies to differentiate endogenous from transfected HO. The purified Adv-HHO construct (10(8) pfu/ml) was mixed with lipofectamine and microinjected into the anterior chamber, vitreous cavity, and subretinal space of New Zealand rabbit eyes. After 2 weeks, total RNA was extracted from different ocular tissues, reverse transcription-polymerase chain reaction was performed using specific human HO-1 primers, and amplification products were subjected to Southern hybridization. Transfection with the Adv-HHO construct into rabbit corneal epithelial cells in culture resulted in a functional expression of the human HO-1 gene; the human HO-1 mRNA was detected, and enzyme activity increased threefold. Human HO-1 mRNA was detected in the retina after microinjection of the Adv-HHO construct into the subretinal space. Microinjection into the vitreous resulted in HO-1 mRNA expression in the corneal endothelium, iris, lens, and retina; after intracameral injection of the Adv-HHO construct, human HO-1 mRNA was detected in corneal epithelium and endothelium, ciliary body, lens, and iris. Regardless of the injection site, transfected human HO-1 mRNA was undetectable in tissues outside the eye, that is, brain, liver, and kidney. These results demonstrated a tissue-selective functional transfer of the human HO-1 gene into rabbit ocular tissues in vivo. This technique may be a promising means for delivering HO-1 gene in vivo as a protective mechanism against oxidative stress that contributes to the pathogenesis of ocular diseases such as cataract, light-induced injury, age-related macular degeneration, and diabetic retinopathy.

Preliminary dosimetric evaluation of (166)Ho-TTHMP for human based on biodistribution data in rats.

PubMed

Yousefnia, Hassan; Zolghadri, Samaneh; Jalilian, Amir Reza; Tajik, Mojtaba; Ghannadi-Maragheh, Mohammad

2014-12-01

In this work, the absorbed dose to each organ of human for (166)Ho-TTHMP was evaluated based on biodistribution studies in rats by a RADAR method and was compared with (166)Ho-DOTMP as the only clinically used Ho-166 bone marrow ablative agent. The highest absorbed dose for this complex is observed in red marrow with 0.922mGy/MBq. The results show that (166)Ho-TTHMP has considerable characteristics compared to (166)Ho-DOTMP and can be a good candidate for bone marrow ablation in patients with multiple myeloma. Copyright © 2014 Elsevier Ltd. All rights reserved.

Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

NASA Astrophysics Data System (ADS)

Mao, J.; Fan, S.; Jacob, D. J.; Travis, K.; Naik, V.; Horowitz, L. W.

2012-12-01

The hydroperoxyl radical (HO2) is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involves conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions (TMI) Cu(I)/Cu(II) and Fe(II)/Fe(III) to rapidly convert HO2 to H2O in aerosols. The implied HO2 uptake significantly affects global model predictions of tropospheric OH, ozone, and other species, improving comparisons to observations, and may have a major and previously unrecognized impact on atmospheric oxidant chemistry.

HO-1-mediated macroautophagy: a mechanism for unregulated iron deposition in aging and degenerating neural tissues.

PubMed

Zukor, Hillel; Song, Wei; Liberman, Adrienne; Mui, Jeannie; Vali, Hojatollah; Fillebeen, Carine; Pantopoulos, Kostas; Wu, Ting-Di; Guerquin-Kern, Jean-Luc; Schipper, Hyman M

2009-05-01

Oxidative stress, deposition of non-transferrin iron, and mitochondrial insufficiency occur in the brains of patients with Alzheimer disease (AD) and Parkinson disease (PD). We previously demonstrated that heme oxygenase-1 (HO-1) is up-regulated in AD and PD brain and promotes the accumulation of non-transferrin iron in astroglial mitochondria. Herein, dynamic secondary ion mass spectrometry (SIMS) and other techniques were employed to ascertain (i) the impact of HO-1 over-expression on astroglial mitochondrial morphology in vitro, (ii) the topography of aberrant iron sequestration in astrocytes over-expressing HO-1, and (iii) the role of iron regulatory proteins (IRP) in HO-1-mediated iron deposition. Astroglial hHO-1 over-expression induced cytoplasmic vacuolation, mitochondrial membrane damage, and macroautophagy. HO-1 promoted trapping of redox-active iron and sulfur within many cytopathological profiles without impacting ferroportin, transferrin receptor, ferritin, and IRP2 protein levels or IRP1 activity. Thus, HO-1 activity promotes mitochondrial macroautophagy and sequestration of redox-active iron in astroglia independently of classical iron mobilization pathways. Glial HO-1 may be a rational therapeutic target in AD, PD, and other human CNS conditions characterized by the unregulated deposition of brain iron.

Omeprazole induces heme oxygenase-1 in fetal human pulmonary microvascular endothelial cells via hydrogen peroxide-independent Nrf2 signaling pathway

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

Patel, Ananddeep; Zhang, Shaojie; Shrestha, Amrit

Omeprazole (OM) is an aryl hydrocarbon receptor (AhR) agonist and a proton pump inhibitor that is used to treat humans with gastric acid related disorders. Recently, we showed that OM induces NAD (P) H quinone oxidoreductase-1 (NQO1) via nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent mechanism. Heme oxygenase-1 (HO-1) is another cytoprotective and antioxidant enzyme that is regulated by Nrf2. Whether OM induces HO-1 in fetal human pulmonary microvascular endothelial cells (HPMEC) is unknown. Therefore, we tested the hypothesis that OM will induce HO-1 expression via Nrf2 in HPMEC. OM induced HO-1 mRNA and protein expression in a dose-dependent manner.more » siRNA-mediated knockdown of AhR failed to abrogate, whereas knockdown of Nrf2 abrogated HO-1 induction by OM. To identify the underlying molecular mechanisms, we determined the effects of OM on cellular hydrogen peroxide (H{sub 2}O{sub 2}) levels since oxidative stress mediated by the latter is known to activate Nrf2. Interestingly, the concentration at which OM induced HO-1 also increased H{sub 2}O{sub 2} levels. Furthermore, H{sub 2}O{sub 2} independently augmented HO-1 expression. Although N-acetyl cysteine (NAC) significantly decreased H{sub 2}O{sub 2} levels in OM-treated cells, we observed that OM further increased HO-1 mRNA and protein expression in NAC-pretreated compared to vehicle-pretreated cells, suggesting that OM induces HO-1 via H{sub 2}O{sub 2}-independent mechanisms. In conclusion, we provide evidence that OM transcriptionally induces HO-1 via AhR - and H{sub 2}O{sub 2} - independent, but Nrf2 - dependent mechanisms. These results have important implications for human disorders where Nrf2 and HO-1 play a beneficial role. - Highlights: • Omeprazole induces HO-1 in human fetal lung cells. • AhR deficiency fails to abrogate omeprazole-mediated induction of HO-1. • Nrf2 knockdown abrogates omeprazole-mediated HO-1 induction in human lung cells. • Hydrogen peroxide depletion augments omeprazole-mediated induction of HO-1.« less

The reciprocal relationship between heme oxygenase and nitric oxide synthase in the organs of lipopolysaccharide-treated rodents.

PubMed

Furuichi, Masayuki; Yokozuka, Motoi; Takemori, Ken; Yamanashi, Yoshitaka; Sakamoto, Atsuhiro

2009-08-01

The production of nitric oxide (NO) by inducible NO synthase (NOS) and carbon monoxide (CO) by inducible heme oxygenase (HO) contributes greatly to endotoxemia. Reciprocal relationships have been proposed between the NO/NOS and CO/HO systems. However, the interaction between these systems during endotoxemia is unclear, and it is unknown whether the interactive behavior differs among organs. Using endotoxic rats, we studied the effects of the inducible NOS (iNOS) inhibitor L-canavanine (CAN), and the HO inhibitor zinc protoporphyrin (ZPP) on gene expression and protein levels of iNOS, endothelial NOS (eNOS), inducible HO (HO-1), and constitutive HO (HO-2) in the brain, lung, heart, liver and kidney tissue. Intravenous injection of LPS significantly increased iNOS and HO-1 gene expression in all organs. The effects of LPS on eNOS gene expression differed among organs, with increased expression in the liver and kidney, and no change in the lung, brain and heart. ZPP administration down-regulated the LPS-induced increase in HO-1 expression and produced a further increase in iNOS expression in all organs. These data suggest that the CO/HO system modifies the NO/NOS system in endotoxic organs, and that there were only minor organ-specific behaviors in terms of the relationship between these systems in the organs examined.

Pivotal Advance: Heme oxygenase 1 expression by human CD4+ T cells is not sufficient for their development of immunoregulatory capacity.

PubMed

Biburger, Markus; Theiner, Gabi; Schädle, Mirjam; Schuler, Gerold; Tiegs, Gisa

2010-02-01

HO-1 is the only inducible one of three isoenzymes that catalyzes the oxidative degradation of heme. HO-1 is inducible by various cellular stress factors and exerts cytoprotective and immunomodulatory effects. Recent publications demonstrated that HO-1 is constitutively expressed by CD4(+)CD25(+) T(regs) and induced in CD4(+)CD25(-) T cells upon FoxP3 transfection. Here, we investigated whether HO-1 was essential and sufficient for human T(regs) to exert immunosuppression in vitro. PGJ(2) induced pronounced expression of HO-1 in CD4(+)CD25(-) T cells without accompanying FoxP3 induction. Treatment of CD4(+)CD25(-) T cells with PGJ(2) decreased their proliferation, whereas the HO-1 inhibitor SnPP enhanced the proliferation of HO-1-expressing T(regs), suggesting that HO-1 may modulate the proliferative capacity of T lymphocytes. HO-1 modulation by SnPP treatment of T(regs) or PGJ(2) treatment of CD4(+)CD25(-) T cells neither suppressed nor induced immune-modulatory function in these cells, respectively, as measured by responder-cell proliferation and/or IL-2 production. In summary, these data suggest that HO-1 expression by T(regs) might contribute to their typical reluctance to proliferate but does not account independently for their suppressive functions.

[hHO-1 structure prediction and its mutant construct, expression, purification and activity analysis].

PubMed

Xia, Zhen Wei; Cui, Wen Jun; Zhou, Wen Pu; Zhang, Xue Hong; Shen, Qing Xiang; Li, Yun Zhu; Yu, Shan Chang

2004-10-01

Human Heme Oxygenase-1 (hHO-1) is the rate-limiting enzyme in the catabolism reaction of heme, which directly regulates the concentration of bilirubin in human body. The mutant structure was simulated by Swiss-pdbviewer procedure, which showed that the structure of active pocket was changed distinctly after Ala25 substituted for His25 in active domain, but the mutated enzyme still binded with heme. On the basis of the results, the expression vectors, pBHO-1 and pBHO-1(M), were constructed, induced by IPTG and expressed in E. coli DH5alpha strain. The expression products were purified with 30%-60% saturation (NH4)2SO4 and Q-Sepharose Fast Flow column chromatography. The concentration of hHO-1 in 30%-60% saturation (NH4)2SO4 components and in fractions through twice column chromatography was 3.6-fold and 30-fold higher than that in initial product, respectively. The activity of wild hHO-1 (whHO-1) and mutant hHO-1 (deltahHO-1) showed that the activity of deltahHO-1 was reduced 91.21% compared with that of whHO-1. The study shows that His25 is of importance for the mechanism of hHO-1, and provides the possibility for effectively regulating the activity to exert biological function.

Bioaccumulation of hydroxylated polychlorinated biphenyls and pentachlorophenol in the serum of northern elephant seal pups (Mirounga angustirostris)

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

Louis, Caroline, E-mail: caroline.louis@uclouvain.be; Covaci, Adrian; Stas, Marie

Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were sampled at 1-, 4-, 7- and 10-week post-weaning. Concentrations of hydroxylated polychlorinated biphenyls (HO-PCBs) and their parent PCBs were measured in the serum of each individual. The ΣHO-PCB concentrations in the serum increased significantly between early and late fast (from 282±20 to 529±31 pg/mL). This increase might result from a mobilisation of HO-PCBs transferred from the mother during gestation and/or lactation and stored in the pup's liver. Food deprivation has been shown to exacerbate biotransformation capacities in mammals, birds and fish. The HO-penta-CBs was themore » predominant homologue group, followed by HO-hexa-CBs and HO-hepta-CBs. No preferential pathway for the metabolism of HO-PCBs (HO-direct insertion or NIH-shift of a chlorine atom) could be evidenced. The concentrations of pentachlorophenol (PCP) in the serum of weaned NES increased from 103±7 pg/mL at early fast to 246±41 pg/mL at late fast, which is within the range of PCP concentrations usually encountered in marine mammals. - Highlights: • Σ HO-PCB concentrations in serum significantly increased between early and late fast. • The HO-penta-CBs were the predominant homologue group measured in serum. • No preferential pathway for the metabolism of HO-PCBs could be evidenced. • PCP concentrations in serum significantly increased between early and late fast.« less

Activation of AMPK stimulates heme oxygenase-1 gene expression and human endothelial cell survival

PubMed Central

Liu, Xiao-ming; Peyton, Kelly J.; Shebib, Ahmad R.; Wang, Hong; Korthuis, Ronald J.

2011-01-01

The present study determined whether AMP-activated protein kinase (AMPK) regulates heme oxygenase (HO)-1 gene expression in endothelial cells (ECs) and if HO-1 contributes to the biological actions of this kinase. Treatment of human ECs with the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) stimulated a concentration- and time-dependent increase in HO-1 protein and mRNA expression that was associated with a prominent increase in nuclear factor-erythroid 2-related factor 2 (Nrf2) protein. Induction of HO-1 was also observed in rat carotid arteries after the in vivo application of AICAR. Induction of HO-1 by AICAR was blocked by the AMPK inhibitor compound C, the adenosine kinase inhibitor 5′-iodotubercidin, and by silencing AMPK-α1/2 and was mimicked by the AMPK activator A-769662 and by infecting ECs with an adenovirus expressing constitutively active AMPK-α1. AICAR also induced a significant rise in HO-1 promoter activity that was abolished by mutating the antioxidant responsive elements of the HO-1 promoter or by the overexpression of dominant negative Nrf2. Finally, activation of AMPK inhibited cytokine-mediated EC death, and this was prevented by the HO inhibitor tin protoporphyrin-IX or by silencing HO-1 expression. In conclusion, AMPK stimulates HO-1 gene expression in human ECs via the Nrf2/antioxidant responsive element signaling pathway. The induction of HO-1 mediates the antiapoptotic effect of AMPK, and this may provide an important adaptive response to preserve EC viability during periods of metabolic stress. PMID:21037234

Non-coding RNA derived from the region adjacent to the human HO-1 E2 enhancer selectively regulates HO-1 gene induction by modulating Pol II binding

PubMed Central

Maruyama, Atsushi; Mimura, Junsei; Itoh, Ken

2014-01-01

Recent studies have disclosed the function of enhancer RNAs (eRNAs), which are long non-coding RNAs transcribed from gene enhancer regions, in transcriptional regulation. However, it remains unclear whether eRNAs are involved in the regulation of human heme oxygenase-1 gene (HO-1) induction. Here, we report that multiple nuclear-enriched eRNAs are transcribed from the regions adjacent to two human HO-1 enhancers (i.e. the distal E2 and proximal E1 enhancers), and some of these eRNAs are induced by the oxidative stress-causing reagent diethyl maleate (DEM). We demonstrated that the expression of one forward direction (5′ to 3′) eRNA transcribed from the human HO-1 E2 enhancer region (named human HO-1enhancer RNA E2-3; hereafter called eRNA E2-3) was induced by DEM in an NRF2-dependent manner in HeLa cells. Conversely, knockdown of BACH1, a repressor of HO-1 transcription, further increased DEM-inducible eRNA E2-3 transcription as well as HO-1 expression. In addition, we showed that knockdown of eRNA E2-3 selectively down-regulated DEM-induced HO-1 expression. Furthermore, eRNA E2-3 knockdown attenuated DEM-induced Pol II binding to the promoter and E2 enhancer regions of HO-1 without affecting NRF2 recruitment to the E2 enhancer. These findings indicate that eRNAE2-3 is functional and is required for HO-1 induction. PMID:25404134

Characterization of a low frequency magnetic noise from a two-stage pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Eshraghi, M. J.; Sasada, I.; Kim, J. M.; Lee, Y. H.

2009-07-01

Magnetic noise of a two-stage pulse tube cryocooler (PT) was measured by a fundamental mode orthogonal fluxgate magnetometer and by a LTS Double Relaxation Oscillation SQUID (DROS) first-order planar gradiometer. The magnetometer was installed in a dewar made of aluminum at 12 cm distance from a section containing magnetic regenerative materials of the second pulse tube. The magnetic noise spectrum showed a clear peak at 1.8 Hz, which is the fundamental frequency of the He gas pumping rate. The 1.8 Hz magnetic noise registered a peak, during the cooling down process, when the second cold-stage temperature was around 12 K, which is well correlated with the 1.8 Hz variation of the temperature of the second cold stage. Hence, we attributed the main source of this magnetic noise to the temperature variation of the magnetic moments resulting from magnetic regenerative materials, Er 3Ni and HoCu 2, in the presence of background static magnetic fields. We have also pointed out that the superconducting magnetic shield of lead sheets reduced the low frequency magnetic noise generated from the magnetic regenerative materials. With this arrangement, the magnetic noise amplitude measured with the LTS DROS gradiometer, mounted at 7 cm horizontal distance from the magnetic regenerative materials, in the optimum condition, was lower than 500 pT peak-to-peak, whereas the noise level without lead shielding was higher than the dynamic range of DROS instrumentations which was around ±10nT.

Heteromorphic NiCo2S4/Ni3S2/Ni Foam as a Self-Standing Electrode for Hydrogen Evolution Reaction in Alkaline Solution.

PubMed

Liu, Hui; Ma, Xiao; Rao, Yuan; Liu, Yang; Liu, Jialiang; Wang, Luyang; Wu, Mingbo

2018-04-04

Considerable works have been devoted on developing high-efficiency nonplatinum electrocatalysts for hydrogen evolution reaction (HER). Herein, 3D heteromorphic NiCo 2 S 4 /Ni 3 S 2 nanosheets network has been constructed on Ni foam (denoted as NiCo 2 S 4 /Ni 3 S 2 /NF) serving as a self-standing electrocatalyst through directly thermal sulfurization of a single-source NiCo-layered double hydroxide precursor. The resultant NiCo 2 S 4 /Ni 3 S 2 /NF electrode exhibits outstanding electrocatalytic HER performance with an extremely low onset overpotential of 15 mV and long-term durability in alkaline solution. Such enhanced HER performance can be credited to (1) the massive exposed active sites provided by mixed transition metal chalcogenides (NiCo 2 S 4 and Ni 3 S 2 ), (2) the strong interfacial interaction at NiCo 2 S 4 /Ni 3 S 2 heterojunction interfaces with the strengthened H binding, and (3) the porous highly conductive Ni foam substrate with accelerated electron transfer. This work opens up a new direction to fabricate effective and non-noble-metal electrodes for water splitting and hydrogen generation.

HOED: Hypermedia Online Educational Database.

ERIC Educational Resources Information Center

Duval, E.; Olivie, H.

This paper presents HOED, a distributed hypermedia client-server system for educational resources. The aim of HOED is to provide a library facility for hyperdocuments that is accessible via the world wide web. Its main application domain is education. The HOED database not only holds the educational resources themselves, but also data describing…

A Biographical Approach to Chinese Political Analysis

DTIC Science & Technology

1975-10-01

Liu Po-ch’eng Chang Kuo -t ’ao Ch’en I Su Yll Lin Piao Nieh Jung -chen Sources: William Whitson, "The Field Army in Chinese Communist Military...since 1954 Founders 1, 2, 3, 5, 6 Ho Lung 12, 13, 14, 15, HeU Haiang-ch’ien 16, 18, 60 (in Liu Po-ch ’eng Szechwan), 61, 62 Chang Kuo -t’ ao 20...66, 67. 68 Nieh Jung -chen Sources: William Whitson, "The Field Army in Chinese Communist Military Politics," The China Quarterly, No, 37, Januar y

Heavy metals and polycyclic aromatic hydrocarbons: pollution and ecological risk assessment in street dust of Tehran.

PubMed

Saeedi, Mohsen; Li, Loretta Y; Salmanzadeh, Mahdiyeh

2012-08-15

50 street dust samples from four major streets in eastern and southern Tehran, the capital of Iran, were analyzed for metal pollution (Cu, Cr, Pb, Ni, Cd, Zn, Fe, Mn and Li). Hakanson's method was used to determine the Risk Index (RI) and ecological risks. Amongst these samples, 21 were also analyzed for polycyclic aromatic hydrocarbons (PAHs). Correlation, cluster and principal component analyses identified probable natural and anthropogenic sources of contaminants. The dust had elevated concentrations of Pb, Cd, Cu, Cr, Ni, Zn, Fe and PAHs. Enrichment factors of Cu, Pb, Cd and Zn showed that the dust is extremely enriched in these metals. Multivariate statistical analyses revealed that Cu, Pb, Zn, Fe and PAHs and, to a lesser extent, Cr and Ni have common anthropogenic sources. While Mn and Li were identified to have natural sources, Cd may have different anthropogenic origins. All samples demonstrated high ecological risk. Traffic and related activities, petrogenic and pyrogenic sources are likely to be the main anthropogenic sources of heavy metals and PAHs in Tehran dust. Copyright © 2012 Elsevier B.V. All rights reserved.

Trace-element evidence for the origin of desert varnish by direct aqueous atmospheric deposition

NASA Astrophysics Data System (ADS)

Thiagarajan, Nivedita; Aeolus Lee, Cin-Ty

2004-07-01

Smooth rock surfaces in arid environments are often covered with a thin coating of Fe-Mn oxyhydroxides known as desert varnish. It is debated whether such varnish is formed (a) by slow diagenesis of dust particles deposited on rock surfaces, (b) by leaching from the underlying rock substrate, or (c) by direct deposition of dissolved constituents in the atmosphere. Varnishes collected from smooth rock surfaces in the Mojave Desert and Death Valley, California are shown here to have highly enriched and fractionated trace-element abundances relative to upper continental crust (UCC). They are highly enriched in Co, Ni, Pb and the rare-earth elements (REEs). In particular, they have anomalously high Ce/La and low Y/Ho ratios. These features can only be explained by preferential scavenging of Co, Ni, Pb and the REEs by Fe-Mn oxyhydroxides in an aqueous environment. High field strength elements (HFSEs: Zr, Hf, Ta, Nb, Th), however, show only small enrichments despite the fact that these elements should also be strongly scavenged by Fe-Mn oxyhydroxides. This suggests that their lack of enrichment is a feature inherited from a solution initially poor in HFSEs. The first two scenarios for varnish formation can be ruled out as follows. The high enrichment factors of Fe, Mn and many trace elements cannot be generated by mass loss associated with post-depositional diagenesis of dust particles because such a process predicts only a small increase in concentration. In addition, the highly fractionated abundance patterns of particle reactive element pairs (e.g., Ce/La and Y/Ho) rules out leaching of the rock substrate. This is because if leaching were to occur, varnishes would grow from the inside to the outside, and thus any particle-reactive trace element leached from the substrate would be quantitatively sequestered in the Fe-Mn oxyhydroxide layers, prohibiting any significant elemental fractionations. One remaining possibility is that the Fe, Mn and trace metals in varnish are derived from leaching of dust particles entrained in rain or fog droplets either in the atmosphere or during wet atmospheric deposition. The high trace metal enrichment factors require that most of the dust was physically removed before or during varnish formation. The remaining aqueous counterpart would be depleted in HFSEs and Th relative to the REEs, Co, Ni and Pb because the former are more insoluble and hence largely retained in the removed dust fraction. The high Ce/La ratios suggest that precipitation of trace metals may have been governed by equilibrium partitioning in an excess of wet atmospheric deposition. If varnishes are indeed derived from wet atmospheric deposition, they may provide a record of the aqueous component of atmospheric dust inputs to various environments.

Selective activation of heme oxygenase-2 by menadione.

PubMed

Vukomanovic, Dragic; McLaughlin, Brian E; Rahman, Mona N; Szarek, Walter A; Brien, James F; Jia, Zongchao; Nakatsu, Kanji

2011-11-01

While substantial progress has been made in elucidating the roles of heme oxygenases-1 (HO-1) and -2 (HO-2) in mammals, our understanding of the functions of these enzymes in health and disease is still incomplete. A significant amount of our knowledge has been garnered through the use of nonselective inhibitors of HOs, and our laboratory has recently described more selective inhibitors for HO-1. In addition, our appreciation of HO-1 has benefitted from the availability of tools for increasing its activity through enzyme induction. By comparison, there is a paucity of information about HO-2 activation, with only a few reports appearing in the literature. This communication describes our observations of the up to 30-fold increase in the in-vitro activation of HO-2 by menadione. This activation was due to an increase in Vmax and was selective, in that menadione did not increase HO-1 activity.

Nano-jewels in biology. Gold and platinum on diamond nanoparticles as antioxidant systems against cellular oxidative stress.

PubMed

Martín, Roberto; Menchón, Cristina; Apostolova, Nadezda; Victor, Victor M; Alvaro, Mercedes; Herance, José Raúl; García, Hermenegildo

2010-11-23

Diamond nanoparticles (DNPs) obtained by explosive detonation have become commercially available. These commercial DNPs can be treated under Fenton conditions (FeSO(4) and H(2)O(2) at acidic pH) to obtain purer DNP samples with a small average particle size (4 nm) and a large population of surface OH groups (HO-DNPs). These Fenton-treated HO-DNPs have been used as a support of gold and platinum nanoparticles (≤2 nm average size). The resulting materials (Au/HO-DNP and Pt/HO-DNP) exhibit a high antioxidant activity against reactive oxygen species induced in a hepatoma cell line. In addition to presenting good biocompatibility, Au/HO- and Pt/HO-DNP exhibit about a two-fold higher antioxidant activity than glutathione, one of the reference antioxidant systems. The most active material against cellular oxidative stress was Au/HO-DNP.

Topics in Ho Morphophonology and Morphosyntax

ERIC Educational Resources Information Center

Pucilowski, Anna

2013-01-01

Ho, an under-documented North Munda language of India, is known for its complex verb forms. This dissertation focuses on analysis of several features of those complex verbs, using data from original fieldwork undertaken by the author. By way of background, an analysis of the phonetics, phonology and morphophonology of Ho is first presented. Ho has…

Is the Health of the Nation Outcome Scales appropriate for the assessment of symptom severity in patients with substance-related disorders?

PubMed

Andreas, Sylke; Harries-Hedder, Karin; Schwenk, Wolfgang; Hausberg, Maria; Koch, Uwe; Schulz, Holger

2010-07-01

The Health of the Nation Outcome Scales (HoNOS) is an internationally established clinician-rated instrument. The aim of the study was to assess the psychometric properties in inpatients with substance-related disorders. The HoNOS was applied in a multicenter, consecutive sample of 417 inpatients. Interrater reliability coefficients, confirmatory factor analysis, and regression tree analyses were calculated to assess the reliability and validity of the HoNOS. The factor validity of the HoNOS and its total score could not be confirmed. After training, all items of the HoNOS revealed sufficient values of interrater reliabilities. As the results of the regression tree analyses showed, the single items of the HoNOS were one of the most important predictor of service utilization. The HoNOS can be recommended for obtaining detailed ratings of the problems of inpatients with substance-related disorders as a clinical application in routine mental health care at present. Further studies should include comparisons of HoNOS and Addiction Severity Index. Copyright 2010 Elsevier Inc. All rights reserved.

Phase relations in the system Cu-Ho-O and stability of Cu{sub 2}Ho{sub 2}O{sub 5}

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

Matthews, T.; Jacob, K.T.

1994-01-01

The phase relations in the system Cu-Ho-O have been determined at 1300 K using X-ray diffraction, optical microscopy, and electron microprobe analysis of samples equilibrated in evacuated quartz ampules and in pure oxygen. Only one ternary compound, Cu{sub 2}Ho{sub 2}O{sub 5}, was found to be stable. The Gibbs free energy of formation of this compound has been measured. Since the formation is endothermic, Cu{sub 2}Ho{sub 2}O{sub 5} becomes thermodynamically unstable with respect to CuO and Ho{sub 2}O{sub 3} below 810 K. When the oxygen partial pressure over Cu{sub 2}Ho{sub 2}O{sub 5} is lowered, it decomposes. The decomposition temperature at anmore » oxygen partial pressure of 1.52 X 10{sup 4} Pa was measured using a combined DTA-TGA apparatus. Based on these results, an oxygen potential diagram for the system Cu-Ho-O at 1300 K is presented.« less

Heme oxygenase-1 in tumor biology and therapy.

PubMed

Was, Halina; Dulak, Jozef; Jozkowicz, Alicja

2010-12-01

Heme oxygenase-1 (HO-1) degrades heme to carbon monoxide (CO), biliverdin, and ferrous iron. As HO-1 expression is highly increased by stressful conditions, the major role of the enzyme is the protection against oxidative injury. Additionally, it regulates cell proliferation, modulates inflammatory response and facilitates angiogenesis. Beneficial activities of HO-1 have been recognized in many pathological states e.g. atherosclerosis, diabetes, ischemia/reperfusion injury or organ transplantation. Interestingly HO-1 expression is very often boosted in tumor tissues and could be further elevated in response to radio-, chemo-, or photodynamic therapy. A growing body of evidence suggests that HO-1 may play a role in tumor induction and can potently improve the growth and spread of tumors. This review discusses the implications of HO-1 properties for tumor proliferation and cell death, differentiation, angiogenesis and metastasis, and tumor-related inflammation. Finally, it suggests that pharmacological agents that regulate HO activity or HO-1 gene silencing may become powerful tools for preventing the onset or progression of various cancers and sensitize them to anticancer therapies.

Synthesis, crystal structure, optical and thermal properties of lanthanide hydrogen-polyphosphates Ln[H(PO3)4] (Ln = Tb, Dy, Ho).

PubMed

Förg, Katharina; Höppe, Henning A

2015-11-28

Lanthanide hydrogen-polyphosphates Ln[H(PO3)4] (Ln = Tb, Dy, Ho) were synthesised as colourless (Ln = Tb, Dy) and light pink (Ln = Ho) crystalline powders by reaction of Tb4O7/Dy2O3/Ho2O3 with H3PO3 at 380 °C. All compounds crystallise isotypically (P2(1)/c (no. 14), Z = 4, a(Tb) = 1368.24(4) pm, b(Tb) = 710.42(2) pm, c(Tb) = 965.79(3) pm, β(Tb) = 101.200(1)°, 3112 data, 160 parameters, wR2 = 0.062, a(Ho) = 1363.34(5) pm, b(Ho) = 709.24(3) pm, c(Ho) = 959.07(4) pm, β(Ho) = 101.055(1)°, 1607 data, 158 parameters, wR2 = 0.058). The crystal structure comprises two different infinite helical chains of corner-sharing phosphate tetrahedra. In-between these chains the lanthanide ions are located, coordinated by seven oxygen atoms belonging to four different polyphosphate chains. Vibrational, UV/Vis and fluorescence spectra of Ln[H(PO3)4] (Ln = Tb, Dy, Ho) as well as Dy[H(PO3)4]:Ln (Ln = Ce, Eu) and the magnetic and thermal behaviour of Tb[H(PO3)4] are reported.

Overexpressed human heme Oxygenase-1 decreases adipogenesis in pigs and porcine adipose-derived stem cells.

PubMed

Park, Eun Jung; Koo, Ok Jae; Lee, Byeong Chun

2015-11-27

Adipose-derived mesenchymal stem cells (ADSC) are multipotent, which means they are able to differentiate into several lineages in vivo and in vitro under proper conditions. This indicates it is possible to determine the direction of differentiation of ADSC by controlling the microenvironment. Heme oxygenase 1 (HO-1), a type of antioxidant enzyme, attenuates adipogenicity and obesity. We produced transgenic pigs overexpressing human HO-1 (hHO-1-Tg), and found that these animals have little fatty tissue when autopsied. To determine whether overexpressed human HO-1 suppresses adipogenesis in pigs, we analyzed body weight increases of hHO-1-Tg pigs and wild type (WT) pigs of the same strain, and induced adipogenic differentiation of ADSC derived from WT and hHO-1-Tg pigs. The hHO-1-Tg pigs had lower body weights than WT pigs from 16 weeks of age until they died. In addition, hHO-1-Tg ADSC showed reduced adipogenic differentiation and expression of adipogenic molecular markers such as PPARγ and C/EBPα compared to WT ADSC. These results suggest that HO-1 overexpression reduces adipogenesis both in vivo and in vitro, which could support identification of therapeutic targets of obesity and related metabolic diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural insights into human heme oxygenase-1 inhibition by potent and selective azole-based compounds

PubMed Central

Rahman, Mona N.; Vukomanovic, Dragic; Vlahakis, Jason Z.; Szarek, Walter A.; Nakatsu, Kanji; Jia, Zongchao

2013-01-01

The development of heme oxygenase (HO) inhibitors, especially those that are isozyme-selective, promises powerful pharmacological tools to elucidate the regulatory characteristics of the HO system. It is already known that HO has cytoprotective properties and may play a role in several disease states, making it an enticing therapeutic target. Traditionally, the metalloporphyrins have been used as competitive HO inhibitors owing to their structural similarity with the substrate, heme. However, given heme's important role in several other proteins (e.g. cytochromes P450, nitric oxide synthase), non-selectivity is an unfortunate side-effect. Reports that azalanstat and other non-porphyrin molecules inhibited HO led to a multi-faceted effort to develop novel compounds as potent, selective inhibitors of HO. This resulted in the creation of non-competitive inhibitors with selectivity for HO, including a subset with isozyme selectivity for HO-1. Using X-ray crystallography, the structures of several complexes of HO-1 with novel inhibitors have been elucidated, which provided insightful information regarding the salient features required for inhibitor binding. This included the structural basis for non-competitive inhibition, flexibility and adaptability of the inhibitor binding pocket, and multiple, potential interaction subsites, all of which can be exploited in future drug-design strategies. PMID:23097500

Expression of Heme Oxygenase-1 in Thick Ascending Loop of Henle Attenuates Angiotensin II-Dependent Hypertension

PubMed Central

Drummond, Heather A.; Gousette, Monette U.; Storm, Megan V.; Abraham, Nader G.; Csongradi, Eva

2012-01-01

Kidney-specific induction of heme oxygenase-1 (HO-1) attenuates the development of angiotensin II (Ang II) -dependent hypertension, but the relative contribution of vascular versus tubular induction of HO-1 is unknown. To determine the specific contribution of thick ascending loop of Henle (TALH) -derived HO-1, we generated a transgenic mouse in which the uromodulin promoter controlled expression of human HO-1. Quantitative RT-PCR and confocal microscopy confirmed successful localization of the HO-1 transgene to TALH tubule segments. Medullary HO activity, but not cortical HO activity, was significantly higher in transgenic mice than control mice. Enhanced TALH HO-1 attenuated the hypertension induced by Ang II delivered by an osmotic minipump for 10 days (139±3 versus 153±2 mmHg in the transgenic and control mice, respectively; P<0.05). The lower blood pressure in transgenic mice associated with a 60% decrease in medullary NKCC2 transporter expression determined by Western blot. Transgenic mice also exhibited a 36% decrease in ouabain-sensitive sodium reabsorption and a significantly attenuated response to furosemide in isolated TALH segments,. In summary, these results show that increased levels of HO-1 in the TALH can lower blood pressure by a mechanism that may include alterations in NKCC2-dependent sodium reabsorption. PMID:22323644

Measuring the electron neutrino mass with improved sensitivity: the HOLMES experiment

NASA Astrophysics Data System (ADS)

Giachero, A.; Alpert, B. K.; Becker, D. T.; Bennett, D. A.; Biasotti, M.; Brofferio, C.; Ceriale, V.; Ceruti, G.; Corsini, D.; Day, P. K.; De Gerone, M.; Dressler, R.; Faverzani, M.; Ferri, E.; Fowler, J. W.; Fumagalli, E.; Gallucci, G.; Gard, J. D.; Gatti, F.; Hays-Wehle, J. P.; Heinitz, S.; Hilton, G. C.; Köster, U.; Lusignoli, M.; Mates, J. A. B.; Nisi, S.; Nucciotti, A.; Orlando, A.; Parodi, L.; Pessina, G.; Pizzigoni, G.; Puiu, A.; Ragazzi, S.; Reintsema, C. D.; Ribeiro Gomes, M.; Schmidt, D. R.; Schumann, D.; Siccardi, F.; Sisti, M.; Swetz, D. S.; Terranova, F.; Ullom, J. N.; Vale, L. R.

2017-02-01

HOLMES is a new experiment aiming at directly measuring the neutrino mass with a sensitivity below 2 eV . HOLMES will perform a calorimetric measurement of the energy released in the decay of 163Ho. The calorimetric measurement eliminates systematic uncertainties arising from the use of external beta sources, as in experiments with spectrometers. This measurement was proposed in 1982 by A. De Rujula and M. Lusignoli, but only recently the detector technological progress has allowed to design a sensitive experiment. HOLMES will deploy a 1000 pixels array of low temperature microcalorimeters with implanted 163Ho nuclei. HOLMES, besides being an important step forward in the direct neutrino mass measurement with a calorimetric approach, will also establish the potential of this approach to extend the sensitivity down to 0.1 eV and lower. The detectors used for the HOLMES experiment will be Mo/Cu bilayers TESs (Transition Edge Sensors) on SiNx membrane with gold absorbers. Microwave multiplexed rf-SQUIDs are the best available technique to read out large array of such detectors. An extensive R&D activity is in progress in order to maximize the multiplexing factor while preserving the performances of the individual detectors. To embed the 163Ho into the gold absorbers a custom mass separator ion implanter is being developed. The current activities are focused on the the single detector performances optimization and on the 163Ho isotope production and embedding. A preliminary measurement of a sub-array of 4× 16 detectors is planned late in 2017. In this contribution we present the HOLMES project with its technical challenges, its status and perspectives.

Controlled synthesis, formation mechanism, and carbon oxidation properties of Ho2Cu2O5 nanoplates prepared with a coordination-complex method

NASA Astrophysics Data System (ADS)

Guo, Rui; You, Junhua; Han, Fei; Li, Chaoyang; Zheng, Guiyuan; Xiao, Weicheng; Liu, Xuanwen

2017-02-01

Ho2Cu2O5 nanoplates with perovskite structures were synthesized via a simple solution method (SSM) and a coordination-complex method (CCM) using [HoCu(3,4-pdc)2(OAc)(H2O)3]·8H2O (L = 3,4-pyridinedicarboxylic acid) as a precursor. The CCM was also performed in an N2 environment (CCMN) under various calcination conditions. The crystallization processes were characterized using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Ho2Cu2O5 formed through the diffusion of CuO into Ho2O3 particles. Cu2+ diffused faster than Ho3+ during this process. The initial products of CCMN (along with the thermal decomposition products) were initially laminarized in the N2 atmosphere, which prevented the growth of CuO particles and decreased the size of the Ho2Cu2O5 particles. The final Ho2Cu2O5 particles from CCMN had a nanoplate morphology with an average thickness of 75 nm. The decomposition of organic molecules and protection from N2 played important roles in determining the morphology of the resulting Ho2Cu2O5. The catalytic oxidation activity of Ho2Cu2O5 samples for carbon was characterized using a specific surface area measurement and thermogravimetric analysis, which revealed that the samples produced by CCMN had the highest catalytic activity.

Optical spectroscopy and luminescence properties of Ho3+ doped zinc fluorophosphate (ZFP) glasses for green luminescent device applications

NASA Astrophysics Data System (ADS)

Reddy Prasad, V.; Damodaraiah, S.; Ratnakaram, Y. C.

2018-04-01

Ho3+ doped zinc fluorophosphate (ZFP) glasses with molar chemical compositions, (60-x) NH4H2PO4+20ZnO+10BaF2+10NaF+xHo2O3 (where x = 0.1, 0.3, 0.5, 1.0 and 1.5 mol%) were prepared by melt quenching technique. These glasses were characterized through physical, structural, optical, excitation, luminescence and decay curve analysis. From the absorption spectra, spectral intensities (fexp and fcal), Judd-Ofelt intensity parameters (Ω2, Ω4 and Ω6), radiative transition probabilities (AT), radiative lifetimes (τR) and branching ratios (βR) were evaluated for all Ho3+ doped ZFP glass matrices. From the photoluminescence spectra, peak stimulated emission cross-sections (σP) were calculated for all Ho3+ doped ZFP glasses. The Ho3+ doped ZFP glasses show strong green emission at 545 nm and red emission at 656 nm under excitation, 450 nm. The measured lifetimes (τmeas) of (5S2)5F4 level of Ho3+ doped ZFP glasses were obtained from decay profiles. The CIE color coordinates of Ho3+ doped ZFP glasses were calculated from emission spectra and 1.0 mol% of Ho3+ doped ZFP glass matrix gives green emission. Hence, these results confirm that the Ho3+ doped ZFP glasses could be considered as a promising candidate for visible green laser applications.

Perceptions About the Present and Future of Surgical Simulation: A National Study of Mixed Qualitative and Quantitative Methodology.

PubMed

Yiasemidou, Marina; Glassman, Daniel; Tomlinson, James; Song, David; Gough, Michael J

Assess expert opinion on the current and future role of simulation in surgical education. Expert opinion was sought through an externally validated questionnaire that was disseminated electronically. Heads of Schools of Surgery (HoS) (and deputies) and Training Program Directors (TPD) (and deputies). Simulation was considered a good training tool (HoS: 15/15, TPD: 21/21). The concept that simulation is useful mostly to novices and for basic skills acquisition was rejected (HoS: 15/15, TPDs: 21/21; HoS: 13/15, TPDs: 18/21). Further, simulation is considered suitable for teaching nontechnical skills (HoS: 13/15, TPDs: 20/21) and re-enacting stressful situations (HoS: 14/15, TPDs: 15/21). Most respondents also felt that education centers should be formally accredited (HoS: 12/15, TPDs: 16/21) and that consultant mentors should be appointed by every trust (HoS: 12/15, TPDs: 19/21). In contrast, there were mixed views on its use for trainee assessment (HoS: 6/15, TPDs: 14/21) and whether it should be compulsory (HoS: 8/15, TPDs: 11/21). The use of simulation for the acquirement of both technical and nontechnical skills is strongly supported while views on other applications (e.g., assessment) are conflicting. Further, the need for center accreditation and supervised, consultant-led teaching is highlighted. Copyright © 2016 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

The role of heme oxygenase-1 in systemic-onset juvenile idiopathic arthritis.

PubMed

Takahashi, Akitaka; Mori, Masaaki; Naruto, Takuya; Nakajima, Shoko; Miyamae, Takako; Imagawa, Tomoyuki; Yokota, Shumpei

2009-01-01

We have determined the serum levels of heme oxygenase-1 (HO-1) in 56 patients with systemic-onset juvenile idiopathic arthritis (s-JIA) and compared these with serum HO-1 levels in healthy controls and patients with other pediatric rheumatic diseases. Serum HO-1 levels were measured by the sandwich enzyme-linked immunosorbent assay. The mean serum HO-1 level in s-JIA patients during the active phase was 123.6 +/- 13.83 ng/ml, which was significantly higher than that in patients with polyarticular juvenile idiopathic arthritis (p-JIA), Kawasaki disease, systemic lupus erythematosus or mixed connective tissue disease (P < 0.0005). The serum levels of HO-1, cytokines and cytokine receptors in patients with s-JIA were also assessed at both the active and inactive phases. The serum HO-1 level in patients with s-JIA in the active phase was found to be significantly greater than that in patients with the disease in the inactive phase (P < 0.0001). An assessment of the relationships between serum HO-1 levels and other laboratory parameters or cytokines in patients with s-JIA did not reveal any strong correlations. These results suggest that the serum level of HO-1 may be a useful marker for the differential diagnosis of s-JIA. Further study will be necessary to elucidate the mechanism of HO-1 production and to clarify the role of HO-1 in the disease process.

Down-regulation of cellular protein heme oxygenase-1 inhibits proliferation of avian influenza virus H9N2 in chicken oviduct epithelial cells.

PubMed

Qi, Xuefeng; Zhang, Huizhu; Xue, Tianxia; Yang, Bo; Deng, Meiyu; Wang, Jingyu

2018-01-01

The pathogenesis of H9N2 subtype avian influenza virus (AIV) infection in hens is often related to oviduct tissue damage. Our previous study suggested that H9N2 AIV induces cellular apoptosis by activating reactive oxygen species (ROS) accumulation and mitochondria-mediated apoptotic signalling in chicken oviduct epithelial cells (COECs). Heme oxygenase-1 (HO-1) is an inducible enzyme that exerts protective effects against oxidative stress and activated HO-1 was recently shown to have antiviral activity. To study the potential involvement of HO-1 in H9N2 AIV proliferation, the role of its expression in H9N2-infected COECs was further investigated. Our results revealed that H9N2 AIV infection significantly up-regulated the expression of HO-1 and that HO-1 down-regulation by ZnPP, a classical inhibitor of HO-1, could inhibit H9N2 AIV replication in COECs. Similarly, the small interfering RNA (siRNA)-mediated knockdown of HO-1 also markedly decreased the virus production in H9N2-infected COECs. In contrast, adenoviral-mediated over-expression of HO-1 concomitantly promoted H9N2 AIV replication. Taken together, our study demonstrated the involvement of HO-1 in AIV H9N2 proliferation, and these findings suggested that HO-1 is a potential target for inhibition of AIV H9N2 replication.

Upregulation of heme oxygenase-1 protected against brain damage induced by transient cerebral ischemia-reperfusion injury in rats.

PubMed

Lu, Xiufang; Gu, Renjun; Hu, Weimin; Sun, Zhitang; Wang, Gaiqing; Wang, Li; Xu, Yuming

2018-06-01

The aim of the present study was to identify the effect of heme oxygenase (HO)-1 gene on cerebral ischemia-reperfusion injury. Sprague-Dawley rats were divided randomly into four groups: Sham group, vehicle group, empty adenovirus vector (Ad) group and recombinant HO-1 adenovirus (Ad-HO-1) transfection group. Rats in the vehicle, Ad and Ad-HO-1 groups were respectively injected with saline, Ad or Ad-HO-1 for 3 days prior to cerebral ischemia-reperfusion injury. Subsequently, the middle cerebral artery occlusion method was used to establish the model of cerebral ischemia-reperfusion injury. Following the assessment of neurological function, rats were sacrificed, and the infarction volume and apoptotic index in rat brains were measured. Furthermore, the protein expression levels of HO-1 in brain tissues were detected using western blot analysis. Results indicated that the neurological score of the Ad-HO-1 group was significantly increased compared with the Ad or vehicle groups, respectively (P<0.001). The volume of cerebral infarction and the index score of neuronal apoptosis in the vehicle and Ad groups was significantly increased compared with the Ad-HO-1 group (P<0.01). The death of neuronal cells following cerebral ischemia-reperfusion injury reduced remarkably induced by over-expression of HO-1. These findings suggest a neuroprotective role of HO-1 against brain injury induced by transient cerebral ischemia-reperfusion injury.

Inhibition of the NADPH oxidase regulates HO-1 expression in chronic myeloid leukemia

PubMed Central

Singh, Melissa M.; Irwin, Mary E.; Gao, Yin; Ban, Kechen; Shi, Ping; Arlinghaus, Ralph B.; Amin, Hesham M.; Chandra, Joya

2011-01-01

Background Patients with blast crisis phase chronic myelogeneous leukemia (CML) have poor response to tyrosine kinase inhibitors designed to inhibit the BCR-ABL1 oncogene. Recent work has shown that heme oxygenase 1 (HO-1) expression is increased in BCR-ABL1 expressing cells and that inhibition of HO-1 in CML leads to reduced cellular growth suggesting HO-1 may be a plausible target for therapy. Here we sought to clarify the mechanism of HO-1 overexpression and the role of the NADPH oxidase as a contributor to this mechanism in CML. Methods HO-1 expression was evaluated in CML bone marrow specimens from patients in various stages of disease, in a transplant based model for CML and in CML cell lines. Chemical and genetic inhibition of the NADPH oxidase was carried out in CML cells. Results Blast crisis CML patient specimens displayed higher levels of HO-1 staining than chronic or accelerated phase. HO-1 upregulation in BCR-ABL1 expressing cells was suppressed by diphenyliodonium (DPI), a chemical inhibitor of the NADPH oxidase. Targeting the NADPH oxidase through RNAi to Rac1, a dominant negative Rac1 construct or an inhibitor of Rac1 activity also blunted HO-1 protein expression. Moreover, inhibition of the NADPH oxidase by RNAi directed towards p47phox similarly abrogated HO-1 levels. Conclusion BCR-ABL1 expression upregulates HO-1, a survival factor for CML cells. This upregulation is more pronounced in blast crisis CML relative to early stage disease and is mediated by the NADPH oxidase components Rac1 and p47phox. Expression of p47phox is increased in BCR-ABL1 expressing cells. PMID:22139798

Ulinastatin activates haem oxygenase 1 antioxidant pathway and attenuates allergic inflammation

PubMed Central

Song, Dongmei; Song, Geng; Niu, Yinghao; Song, Wei; Wang, Jiantao; Yu, Lei; Yang, Jianwang; Lv, Xin; Steinberg, Harry; Liu, Shu Fang; Wang, Baoshan

2014-01-01

Background and Purpose Ulinastatin (UTI), a serine protease inhibitor, was recently found to have an anti-inflammatory action. However, the mechanisms mediating this anti-inflammatory effect are not well understood. This study tested the hypothesis that UTI suppresses allergic inflammation by inducing the expression of haem oxygenase 1 (HO1). Experimental Approach Control mice and mice sensitized (on days 1, 9 and 14) and challenged (on days 21 to 27) with ovalbumin (OVA) were treated with UTI. The effects of UTI on basal expression of HO1 and that induced by OVA challenge were examined. The involvement of UTI-induced HO1 expression in anti-inflammatory and antioxidant effects of UTI was also evaluated. Key Results UTI markedly increased basal HO1 protein expression in lungs of control mice in a time- and dose-dependent manner, and augmented HO1 protein expression induced by OVA. The up-regulation of HO1 mediated by UTI in sensitized and OVA-challenged mice was associated with reduced airway inflammation, alleviated tissue injury, reduced oxidant stress and enhanced antioxidant enzyme activities. Inhibition of HO1 activity using HO1 inhibitor, zinc protoporphyrin, attenuated inhibitory effects of UTI on inflammation and oxidant stress, and its stimulant effects on antioxidant enzyme activities. Mechanistic analysis showed that UTI increased nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), stimulated Nrf2 DNA binding activity and concomitantly up-regulated HO1 mRNA expression. Conclusions and Implications UTI is a potent and naturally occurring inducer of HO1 expression. HO1 up-regulation contributes significantly to the anti-inflammatory and organ-protective effects of UTI, which has important research and therapeutic implications. PMID:24835359

Difference in occurrence of heterotopic ossification according to prosthesis type in the cervical artificial disc replacement.

PubMed

Yi, Seong; Kim, Keung Nyun; Yang, Moon Sul; Yang, Joong Won; Kim, Hoon; Ha, Yoon; Yoon, Do Heum; Shin, Hyun Chul

2010-07-15

Retrospective study of the difference of heterotopic ossification (HO) occurrence according to 3 different types of prosthesis. This study was designed to investigate the difference of HO occurrence according to different type of prosthesis. HO is defined as formation of the bone outside the skeletal system. Reported HO occurrence rate in cervical artificial disc replacement (ADR) was unexpectedly high and varied. But the influencing factors of HO in cervical ADR have not been elucidated well. The prosthesis-related factors for making difference of HO occurrence were investigated in this study. A total of 170 patients undergoing cervical arthroplasty with the Bryan cervical disc prosthesis (Medtroic Sofamor Danek, Memphis, TN), Mobi-C disc prosthesis (LDR Medical, Troyes, France), and ProDisc-C (Synthes, Inc., West Chester, PA) were included. Cervical lateral radiographs obtained before and after surgery were used to identify HO. Occurrence rate, occurrence-free period, location, and grade of HOs were investigated according to the different prosthesis. Each prosthesis group included patients as follows: Bryan disc, 81 patients; Mobi-C, 61 patients; and ProDisc-C, 28 patients. Overall HO rate was 40.6% (69 of 170 patients). Each HO occurrence rate by prosthesis was as follows: the Bryan disc group, 21.0%; Mobi-C group, 52.5%; and the ProDisc-C group, 71.4%. In the survival analysis, all patients showed 27.1 +/- 3.7 months as the median survival. The Bryan disc group showed statistically longer survival (48.4 +/- 7.4 months) than the other groups. Occurrence of HO is an inevitable postoperative complication after cervical ADR. The occurrence rate of HO was higher than our expectation. Moreover, definite differences in occurrence rate according to the prosthesis type were identified by this study.

Predicting the risk for hospital-onset Clostridium difficile infection (HO-CDI) at the time of inpatient admission: HO-CDI risk score.

PubMed

Tabak, Ying P; Johannes, Richard S; Sun, Xiaowu; Nunez, Carlos M; McDonald, L Clifford

2015-06-01

To predict the likelihood of hospital-onset Clostridium difficile infection (HO-CDI) based on patient clinical presentations at admission Retrospective data analysis Six US acute care hospitals Adult inpatients We used clinical data collected at the time of admission in electronic health record (EHR) systems to develop and validate a HO-CDI predictive model. The outcome measure was HO-CDI cases identified by a nonduplicate positive C. difficile toxin assay result with stool specimens collected >48 hours after inpatient admission. We fit a logistic regression model to predict the risk of HO-CDI. We validated the model using 1,000 bootstrap simulations. Among 78,080 adult admissions, 323 HO-CDI cases were identified (ie, a rate of 4.1 per 1,000 admissions). The logistic regression model yielded 14 independent predictors, including hospital community onset CDI pressure, patient age ≥65, previous healthcare exposures, CDI in previous admission, admission to the intensive care unit, albumin ≤3 g/dL, creatinine >2.0 mg/dL, bands >32%, platelets ≤150 or >420 109/L, and white blood cell count >11,000 mm3. The model had a c-statistic of 0.78 (95% confidence interval [CI], 0.76-0.81) with good calibration. Among 79% of patients with risk scores of 0-7, 19 HO-CDIs occurred per 10,000 admissions; for patients with risk scores >20, 623 HO-CDIs occurred per 10,000 admissions (P<.0001). Using clinical parameters available at the time of admission, this HO-CDI model demonstrated good predictive ability, and it may have utility as an early risk identification tool for HO-CDI preventive interventions and outcome comparisons.

Risk factors for the development of heterotopic ossification in seriously burned adults: A National Institute on Disability, Independent Living and Rehabilitation Research burn model system database analysis.

PubMed

Levi, Benjamin; Jayakumar, Prakash; Giladi, Avi; Jupiter, Jesse B; Ring, David C; Kowalske, Karen; Gibran, Nicole S; Herndon, David; Schneider, Jeffrey C; Ryan, Colleen M

2015-11-01

Heterotopic ossification (HO) is a debilitating complication of burn injury; however, incidence and risk factors are poorly understood. In this study, we use a multicenter database of adults with burn injuries to identify and analyze clinical factors that predict HO formation. Data from six high-volume burn centers, in the Burn Injury Model System Database, were analyzed. Univariate logistic regression models were used for model selection. Cluster-adjusted multivariate logistic regression was then used to evaluate the relationship between clinical and demographic data and the development of HO. Of 2,979 patients in the database with information on HO that addressed risk factors for development of HO, 98 (3.5%) developed HO. Of these 98 patients, 97 had arm burns, and 96 had arm grafts. When controlling for age and sex in a multivariate model, patients with greater than 30% total body surface area burn had 11.5 times higher odds of developing HO (p < 0.001), and those with arm burns that required skin grafting had 96.4 times higher odds of developing HO (p = 0.04). For each additional time a patient went to the operating room, odds of HO increased by 30% (odds ratio, 1.32; p < 0.001), and each additional ventilator day increased odds by 3.5% (odds ratio, 1.035; p < 0.001). Joint contracture, inhalation injury, and bone exposure did not significantly increase odds of HO. Risk factors for HO development include greater than 30% total body surface area burn, arm burns, arm grafts, ventilator days, and number of trips to the operating room. Future studies can use these results to identify highest-risk patients to guide deployment of prophylactic and experimental treatments. Prognostic study, level III.

Effect of heme oxygenase-1 on the protection of ischemia reperfusion injury of bile duct in rats after liver transplantation.

PubMed

Zhan, Xi; Zhang, Zhiqing; Huang, Hanfei; Zhang, Yujun; Zeng, Zhong

2018-06-01

To investigate the effect of heme oxygenase-1 (HO-1) on the ischemic reperfusion injury (IRI) of bile duct in rat models after liver transplantation. 320 SD rats were equally and randomly divided into 5 groups, which were group A receiving injection of 3×10 8 /pfu/ml adenovirus (adv), group B with donor receiving Adv-HO-1 and recipient receiving Adv-HO-1-siRNA, group C with donor and recipient both receiving Adv-HO-1, group D with donor receiving Adv-HO-1-siRNA and recipient receiving Adv-HO-1, and group E with donor and recipient both receiving Adv-HO-1-siRNA at 24h before liver transplantation. Donor liver was stored in UW liquid at 4°C followed by measuring HO-1 level by western blot before transplantation. On d1, d3, d7 and d14, serum and liver was isolated for analysis of liver function, inflammatory cell infiltration by H&E staining, ultrastructure of liver by transmission electron microscopy as well as the expression of HO-1, Bsep, Mrp2 and Ntcp by western blot. Compared with group D and E, group B and C displayed improved liver function as demonstrated by lower level of ALT, AST, LDH, TBIL, ALP and GGT, increased secretion of TBA and PL as well as expression of transporter proteins (Bsep, Mrp2 and Ntcp), reduced inflammatory cells infiltration and liver injury. Our study demonstrated that overexpression of HO-1 in donor liver can ameliorate the damage to bile duct and liver, and improved liver function, suggesting HO-1 might be a new therapeutic target in the treatment of IRI after liver transplantation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Protection from ischemic heart injury by a vigilant heme oxygenase-1 plasmid system.

PubMed

Tang, Yao Liang; Tang, Yi; Zhang, Y Clare; Qian, Keping; Shen, Leping; Phillips, M Ian

2004-04-01

Although human heme oxygenase-1 (hHO-1) could provide a useful approach for cellular protection in the ischemic heart, constitutive overexpression of hHO-1 may lead to unwanted side effects. To avoid this, we designed a hypoxia-regulated hHO-1 gene therapy system that can be switched on and off. This vigilant plasmid system is composed of myosin light chain-2v promoter and a gene switch that is based on an oxygen-dependent degradation domain from the hypoxia inducible factor-1-alpha. The vector can sense ischemia and switch on the hHO-1 gene system, specifically in the heart. In an in vivo experiment, the vigilant hHO-1 plasmid or saline was injected intramyocardially into myocardial infarction mice or sham operation mice. After gene transfer, expression of hHO-1 was only detected in the ischemic heart treated with vigilant hHO-1 plasmids. Masson trichrome staining showed significantly fewer fibrotic areas in vigilant hHO-1 plasmids-treated mice compared with saline control (43.0%+/-4.8% versus 62.5%+/-3.3%, P<0.01). The reduction of interstitial fibrosis is accompanied by an increase in myocardial hHO-1 expression in peri-infarct border areas, concomitant with higher Bcl-2 levels and lower Bax, Bak, and caspase 3 levels in the ischemic myocardium compared with saline control. By use of a cardiac catheter, heart from vigilant hHO-1 plasmids-treated mice showed improved recovery of contractile and diastolic performance after myocardial infarction compared with saline control. This study documents the beneficial regulation and therapeutic potential of vigilant plasmid-mediated hHO-1 gene transfer. This novel gene transfer strategy can provide cardiac-specific protection from future repeated bouts of ischemic injury.

Heme oxygenase-1 (HO-1) inhibits postmyocardial infarct remodeling and restores ventricular function.

PubMed

Liu, Xiaoli; Pachori, Alok S; Ward, Christopher A; Davis, J Paul; Gnecchi, Massimiliano; Kong, Deling; Zhang, Lunan; Murduck, Jared; Yet, Shaw-Fang; Perrella, Mark A; Pratt, Richard E; Dzau, Victor J; Melo, Luis G

2006-02-01

We reported previously that predelivery of the anti-oxidant gene heme oxygenase-1 (HO-1) to the heart by adeno associated virus (AAV) markedly reduces injury after acute myocardial infarction (MI). However, the effect of HO-1 gene delivery on postinfarction recovery has not been investigated. In the current study, we assessed the effect of HO-1 gene delivery on post-MI left ventricle (LV) remodeling and function using echocardiographic imaging and histomorphometric approaches. Two groups of Sprague-Dawley rats were injected with 4 x 10(11) particles of AAV-LacZ (control) or AAV-hHO-1 in the LV wall. Eight wk after gene transfer, the animals were subjected to 30 min of ischemia by ligation of left anterior descending artery (LAD) followed by reperfusion. Echocardiographic measurements were obtained in a blinded fashion prior and at 1.5 and 3 months after I/R. Ejection fraction (EF) was reduced by 13% and 40% in the HO-1 and LacZ groups, respectively at 1.5 months after MI. Three months after MI, EF recovered fully in the HO-1, but only partially in the LacZ-treated animals. Post-MI LV dimensions were markedly increased and the anterior wall was markedly thinned in the LacZ-treated animals compared with the HO-1-treated animals. Significant myocardial scarring and fibrosis were observed in the LacZ-group in association with elevated levels of interstitial collagen I and III and MMP-2 activity. Post-MI myofibroblast accumulation was reduced in the HO-1-treated animals, and retroviral overexpression of HO-1 reduced proliferation of isolated cardiac fibroblasts. Our data indicate that rAAV-HO-1 gene transfer markedly reduces fibrosis and ventricular remodeling and restores LV function and chamber dimensions after myocardial infarction.

Isocyanides inhibit human heme oxygenases at the verdoheme stage.

PubMed

Evans, John P; Kandel, Sylvie; Ortiz de Montellano, Paul R

2009-09-22

Heme oxygenases (HO) catalyze the oxidative cleavage of heme to generate biliverdin, CO, and free iron. In humans, heme oxygenase-1 (hHO-1) is overexpressed in tumor tissues, where it helps to protect cancer cells from anticancer agents, while HOs in fungal pathogens, such as Candida albicans, function as the primary means of iron acquisition. Thus, HO can be considered a potential therapeutic target for certain diseases. In this study, we have examined the equilibrium binding of three isocyanides, isopropyl, n-butyl, and benzyl, to the two major human HO isoforms (hHO-1 and hHO-2), Candida albicans HO (CaHmx1), and human cytochrome P450 CYP3A4 using electronic absorption spectroscopy. Isocyanides coordinate to both ferric and ferrous HO-bound heme, with tighter binding by the more hydrophobic isocyanides and 200-300-fold tighter binding to the ferrous form. Benzyl isocyanide was the strongest ligand to ferrous heme in all the enzymes. Because the dissociation constants (KD) of the ligands for ferrous heme-hHO-1 were below the limit of accuracy for equilibrium titrations, stopped-flow kinetic experiments were used to measure the binding parameters of the isocyanides to ferrous hHO-1. Steady-state activity assays showed that benzyl isocyanide was the most potent uncompetitive inhibitor with respect to heme with a KI = 0.15 microM for hHO-1. Importantly, single turnover assays revealed that the reaction was completely stopped by coordination of the isocyanide to the verdoheme intermediate rather than to the ferric heme complex. Much tighter binding of the inhibitor to the verdoheme intermediate differentiates it from inhibition of, for example, CYP3A4 and offers a possible route to more selective inhibitor design.

Isocyanides Inhibit Human Heme Oxygenases at the Verdoheme Stage†

PubMed Central

Evans, John P.; Kandel, Sylvie; Ortiz de Montellano, Paul R.

2010-01-01

Heme oxygenases (HO) catalyze the oxidative cleavage of heme to generate biliverdin, CO, and free iron. In humans, heme oxygenase-1 (hHO-1) is overexpressed in tumor tissues, where it helps to protect cancer cells from anticancer agents, while HOs in fungal pathogens, such as Candida albicans, function as the primary means of iron acquisition. Thus, HO can be considered a potential therapeutic target for certain diseases. In this study, we have examined the equilibrium binding of three isocyanides; isopropyl, n-butyl, and benzyl, to the two major human HO isoforms (hHO-1 and hHO-2), Candida albicans HO (CaHmx1), and human cytochrome P450 CYP3A4 using electronic absorption spectroscopy. Isocyanides coordinate to both ferric and ferrous HO-bound heme, with tighter binding by the more hydrophobic isocyanides, and 200-300-fold tighter binding to the ferrous form. Benzyl isocyanide was the strongest ligand to ferrous heme in all the enzymes. Because the dissociation constants (KD) of the ligands for ferrous heme-hHO-1 were below the limit of accuracy for equilibrium titrations, stopped-flow kinetic experiments were used to measure the binding parameters of the isocyanides to ferrous hHO-1. Steady-state activity assays showed that benzyl isocyanide was the most potent uncompetitive inhibitor with respect to heme with a KI = 0.15 μM for hHO-1. Importantly, single turnover assays revealed that the reaction was completely stopped by coordination of the isocyanide to the verdoheme intermediate rather than to the ferric heme complex. Much tighter binding of the inhibitor to the verdoheme intermediate differentiates it from inhibition of, for example, CYP3A4 and offers a possible route to more selective inhibitor design. PMID:19694439

HO-1 gene overexpression enhances the beneficial effects of superparamagnetic iron oxide labeled bone marrow stromal cells transplantation in swine hearts underwent ischemia/reperfusion: an MRI study.

PubMed

Jiang, Yibo; Chen, Lijuan; Tang, Yaoliang; Ma, Genshan; Shen, Chengxing; Qi, Chunmei; Zhu, Qi; Yao, Yuyu; Liu, Naifeng

2010-05-01

To determine the effect of intracoronary transfer of superparamagnetic iron oxide (SPIO) labeled heme oxygenase-1 (HO-1) overexpressed bone marrow stromal cells (BMSCs) in a porcine myocardial ischemia/reperfusion model. Cell apoptosis was assayed and supernatant cytokine concentrations were measured in BMSCs that underwent hypoxia/reoxygen in vitro. Female mini-swines that underwent 1 h LAD occlusion followed by 1 h reperfusion were randomly allocated to receive intracoronary saline (control), 1 x 10(7) SPIO-labeled BMSCs transfected with pcDNA3.1-Lacz plasmid (Lacz-BMSCs), pcDNA3.1-human HO-1 (HO-1-BMSCs), pcDNA3.1-hHO-1 pretreated with a HO inhibitor, tin protoporphyrin (SnPP, n = 10 each). MRI and postmortem histological analysis were made at 1 week or 3 months thereafter. Post hypoxia/reoxygen in vitro, apoptosis was significantly reduced, supernatant VEGF significantly increased while TNF-alpha and IL-6 significantly reduced in HO-1-BMSCs group compared with Lacz-BMSCs group (all p < 0.05). Myocardial expression of VEGF was significantly higher in HO-1-BMSCs than in Lacz-BMSCs group at 1 week post transplantation (all p < 0.05). Signal voids induced by the SPIO were detected in the peri-infarction region in all BMSC groups at 1 week but not at 3 months post transplantation and the extent of the hypointense signal was the highest in HO-1-BMSCs group, and histological analysis showed that signal voids represented cardiac macrophages that engulfed the SPIO-labeled BMSCs. Pretreatment with SnPP significantly attenuated the beneficial effects of HO-1-BMSCs. Transplantation of HO-1-overexpressed BMSCs significantly enhanced the beneficial effects of BMSCs on improving cardiac function in this model.

L-ascorbate attenuates methamphetamine neurotoxicity through enhancing the induction of endogenous heme oxygenase-1.

PubMed

Huang, Ya-Ni; Wang, Jiz-Yuh; Lee, Ching-Tien; Lin, Chih-Hung; Lai, Chien-Cheng; Wang, Jia-Yi

2012-12-01

Methamphetamine (METH) is a drug of abuse which causes neurotoxicity and increased risk of developing neurodegenerative diseases. We previously found that METH induces heme oxygenase (HO)-1 expression in neurons and glial cells, and this offers partial protection against METH toxicity. In this study, we investigated the effects of l-ascorbate (vitamin C, Vit. C) on METH toxicity and HO-1 expression in neuronal/glial cocultures. Cell viability and damage were evaluated by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release, respectively. Neuronal and glial localization of HO-1 were identified by double immunofluorescence staining. Reactive oxygen species (ROS) production was measured using the fluorochrome 2',7'-dichlorofluorescin diacetate. HO-1 mRNA and protein expression were examined by RT-qPCR and Western blotting, respectively. Results show that Vit. C induced HO-1 mRNA and protein expressions in time- and concentration-dependent manners. Inhibition of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase (ERK) significantly blocked induction of HO-1 by Vit. C. HO-1 mRNA and protein expressions were significantly elevated by a combination of Vit. C and METH, compared to either Vit. C or METH alone. Pretreatment with Vit. C enhanced METH-induced HO-1 expression and attenuated METH-induced ROS production and neurotoxicity. Pharmacological inhibition of HO activity abolished suppressive effects of Vit. C on METH-induced ROS production and attenuated neurotoxicity. We conclude that induction of HO-1 expression contributes to the attenuation of METH-induced ROS production and neurotoxicity by Vit. C. We suggest that HO-1 induction by Vit. C may serve as a strategy to alleviate METH neurotoxicity. Copyright © 2012 Elsevier Inc. All rights reserved.

Risk Factors for the Development of Heterotopic Ossification in Seriously Burned Adults: A NIDRR Burn Model System Database Analysis

PubMed Central

Levi, Benjamin; Jayakumar, Prakash; Giladi, Avi; Jupiter, Jesse B.; Ring, David C.; Kowalske, Karen; Gibran, Nicole S.; Herndon, David; Schneider, Jeffrey C.; Ryan, Colleen M.

2015-01-01

Purpose Heterotopic ossification (HO) is a debilitating complication of burn injury; however, incidence and risk factors are poorly understood. In this study we utilize a multicenter database of adults with burn injuries to identify and analyze clinical factors that predict HO formation. Methods Data from 6 high-volume burn centers, in the Burn Injury Model System Database, were analyzed. Univariate logistic regression models were used for model selection. Cluster-adjusted multivariate logistic regression was then used to evaluate the relationship between clinical and demographic data and the development of HO. Results Of 2,979 patients in the database with information on HO that addressed risk factors for development of HO, 98 (3.5%) developed HO. Of these 98 patients, 97 had arm burns, and 96 had arm grafts. Controlling for age and sex in a multivariate model, patients with >30% total body surface area (TBSA) burn had 11.5x higher odds of developing HO (p<0.001), and those with arm burns that required skin grafting had 96.4x higher odds of developing HO (p=0.04). For each additional time a patient went to the operating room, odds of HO increased 30% (OR 1.32, p<0.001), and each additional ventilator day increase odds 3.5% (OR 1.035, p<0.001). Joint contracture, inhalation injury, and bone exposure did not significantly increase odds of HO. Conclusion Risk factors for HO development include >30% TBSA burn, arm burns, arm grafts, ventilator days, and number of trips to the operating room. Future studies can use these results to identify highest-risk patients to guide deployment of prophylactic and experimental treatments. PMID:26496115

The cumulative influence of hyperoxia and hypercapnia on blood oxygenation and R2*

PubMed Central

Faraco, Carlos C; Strother, Megan K; Siero, Jeroen CW; Arteaga, Daniel F; Scott, Allison O; Jordan, Lori C; Donahue, Manus J

2015-01-01

Cerebrovascular reactivity (CVR)-weighted blood-oxygenation-level-dependent magnetic resonance imaging (BOLD-MRI) experiments are frequently used in conjunction with hyperoxia. Owing to complex interactions between hyperoxia and hypercapnia, quantitative effects of these gas mixtures on BOLD responses, blood and tissue R2*, and blood oxygenation are incompletely understood. Here we performed BOLD imaging (3 T; TE/TR=35/2,000 ms; spatial resolution=3 × 3 × 3.5 mm3) in healthy volunteers (n=12; age=29±4.1 years) breathing (i) room air (RA), (ii) normocapnic–hyperoxia (95% O2/5% N2, HO), (iii) hypercapnic–normoxia (5% CO2/21% O2/74% N2, HC-NO), and (iv) hypercapnic–hyperoxia (5% CO2/95% O2, HC-HO). For HC-HO, experiments were performed with separate RA and HO baselines to control for changes in O2. T2-relaxation-under-spin-tagging MRI was used to calculate basal venous oxygenation. Signal changes were quantified and established hemodynamic models were applied to quantify vasoactive blood oxygenation, blood–water R2*, and tissue–water R2*. In the cortex, fractional BOLD changes (stimulus/baseline) were HO/RA=0.011±0.007; HC-NO/RA=0.014±0.004; HC-HO/HO=0.020±0.008; and HC-HO/RA=0.035±0.010; for the measured basal venous oxygenation level of 0.632, this led to venous blood oxygenation levels of 0.660 (HO), 0.665 (HC-NO), and 0.712 (HC-HO). Interleaving a HC-HO stimulus with HO baseline provided a smaller but significantly elevated BOLD response compared with a HC-NO stimulus. Results provide an outline for how blood oxygenation differs for several gas stimuli and provides quantitative information on how hypercapnic BOLD CVR and R2* are altered during hyperoxia. PMID:26174329

Loss of heme oxygenase-1 accelerates mesodermal gene expressions during embryoid body development from mouse embryonic stem cells.

PubMed

Lai, Yan-Liang; Lin, Chen-Yu; Jiang, Wei-Cheng; Ho, Yen-Chun; Chen, Chung-Huang; Yet, Shaw-Fang

2018-05-01

Heme oxygenase (HO)-1 is an inducible stress response protein and well known to protect cells and tissues against injury. Despite its important function in cytoprotection against physiological stress, the role of HO-1 in embryonic stem cell (ESC) differentiation remains largely unknown. We showed previously that induced pluripotent stem (iPS) cells that lack HO-1 are more sensitive to oxidant stress-induced cell death and more prone to lose pluripotent markers upon LIF withdrawal. To elucidate the role of HO-1 in ESC differentiation and to rule out the controversy of potential gene flaws in iPS cells, we derived and established mouse HO-1 knockout ESC lines from HO-1 knockout blastocysts. Using wild type D3 and HO-1 knockout ESCs in the 3-dimensional embryoid body (EB) differentiation model, we showed that at an early time point during EB development, an absence of HO-1 led to enhanced ROS level, concomitant with increased expressions of master mesodermal regulator brachyury and endodermal marker GATA6. In addition, critical smooth muscle cell (SMC) transcription factor serum response factor and its coactivator myocardin were enhanced. Furthermore, HO-1 deficiency increased Smad2 in ESCs and EBs, revealing a role of HO-1 in controlling Smad2 level. Smad2 not only mediates mesendoderm differentiation of mouse ESCs but also SMC development. Collectively, loss of HO-1 resulted in higher level of mesodermal and SMC regulators, leading to accelerated and enhanced SMC marker SM α-actin expression. Our results reveal a previously unrecognized function of HO-1 in regulating SMC gene expressions during ESC-EB development. More importantly, our findings may provide a novel strategy in enhancing ESC differentiation toward SMC lineage. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Adenovirus-delivered GFP-HO-1C[INCREMENT]23 attenuates blood-spinal cord barrier permeability after rat spinal cord contusion.

PubMed

Chang, Sheng; Bi, Yunlong; Meng, Xiangwei; Qu, Lin; Cao, Yang

2018-03-21

The blood-spinal cord barrier (BSCB) plays a key role in maintaining the microenvironment and is primarily composed of tight junction proteins and nonfenestrated capillary endothelial cells. After injury, BSCB damage results in increasing capillary permeability and release of inflammatory factors. Recent studies have reported that haem oxygenase-1 (HO-1) fragments lacking 23 amino acids at the C-terminus (HO-1C[INCREMENT]23) exert novel anti-inflammatory and antioxidative effects in vitro. However, no study has identified the role of HO-1C[INCREMENT]23 in vivo. We aimed to investigate the protective effects of HO-1C[INCREMENT]23 on the BSCB after spinal cord injury (SCI) in a rat model. Here, adenoviral HO-1C[INCREMENT]23 (Ad-GFP-HO-1C[INCREMENT]23) was intrathecally injected into the 10th thoracic spinal cord segment (T10) 7 days before SCI. In addition, nuclear and cytoplasmic extraction and immunofluorescence staining of HO-1 were used to examine the effect of Ad-GFP-HO-1C[INCREMENT]23 on HO-1 nuclear translocation. Evan's blue staining served as an index of capillary permeability and was detected by fluorescence microscopy at 633 nm. Western blotting was also performed to detect tight junction protein expression. The Basso, Beattie and Bresnahan score was used to evaluate kinematic functional recovery through the 28th day after SCI. In this study, the Ad-GFP-HO-1C[INCREMENT]23 group showed better kinematic functional recovery after SCI than the Ad-GFP and Vehicle groups, as well as smaller reductions in TJ proteins and capillary permeability compared with those in the Ad-GFP and Vehicle groups. These findings indicated that Ad-GFP-HO-1C[INCREMENT]23 might have a potential therapeutic effect that is mediated by its protection of BSCB integrity.

Establishing the Dependence of [HO2]/[OH] on Temperature, Halogen Loading, O3, and NO(x) Based on in Situ Measurements from the NASA ER-2

NASA Technical Reports Server (NTRS)

Lanzendorf, E. J.; Hanisco, T. F.; Wennberg, P. O.; Cohen, R. C.; Stimpfle, R. M.; Anderson, J. G.; Gao, R. S.; Margitan, J. J.; Bui, T. P.

2001-01-01

In situ observations of OH and HO2 from the Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA), Stratospheric TRacers of Atmospheric Transport (STRAT), and Polar Ozone Loss in the Arctic Region in Summer (POLARIS) NASA ER-2 field campaigns are used to examine the partitioning of HO(x) in the lower stratosphere (tropopause to approx.21 km) and upper troposphere (approx.10 km to tropopause). These measurements span a latitude range from 70degS to 90degN and a variety of atmospheric conditions as a result of seasonal changes and altitude. The response of the observed [HO2]/[OH] to changes in temperature, [03], [CO], [NO], [CIO], and [BrO] is investigated. The measured ratio is accurately described (approx.+/-10%) by a steady-state model constrained by the measured mixing ratios of O3, CO, NO, CIO, and BrO, where the model is valid for conditions of HO(x) cycling much faster than HO(x) production and loss. The concentration of HO2 depends on [OH], which, to first order, has been observed to be a simple function of the solar zenith angle in the lower stratosphere. The partitioning between OH and HO2 is controlled by the local chemistry between the HO, radicals and O3, CO, NO, CIO, and BrO. The response of [HO(x)] to changes in [NO(x)] and [O3] is demonstrated. Further observations are necessary to illustrate the response of HO(x) to changes in halogen concentrations. A quantitative understanding of [HO2]/[OH] is important, since many of the reactions that control this ratio are directly involved in catalytic removal of O3 in the lower stratosphere and production of O3 in the upper troposphere.

Synergistic effect of Fe2O3/Ho2O3 Co-modified 2D-titanate heterojunctions on enhanced photocatalytic degradation

NASA Astrophysics Data System (ADS)

Zhao, Xiaona; Liu, Xinzhao; Lu, Dingze; Wu, Pei; Yan, Qiuyang; Liu, Min; Fang, Pengfei

2017-01-01

TiO2-based nanosheets (TNSs) co-modified by Fe2O3 and Ho2O3 were synthesized by one-pot hydrothermal method using Fe(NO3)3 and Ho(NO3)3 as precursors compositing with TiO2. The Fe2O3/Ho2O3-TNSs heterojunctions possessed a thickness of approximately 3-4 nm, large specific surface area of 210-310 cm2/g, with Fe2O3 and Ho2O3 nanoparticles highly dispersed over the surface of the nanosheets. The crystallization of the samples gradually increased with the amount of Fe2O3 nanoparticles, which was confirmed by the XRD, BET and Raman spectra, indicating that Ho2O3 and Fe2O3 influenced the crystallinity and structure evolution of the TNSs, besides, led to an improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be efficiently improved by an appropriate amount of modification. The Fe2O3/Ho2O3-TNSs exhibited synergistic effect on photocatalytic degradation of RhB as well as MO under visible light. The highest efficiency was obtained by 0.05%-Fe2O3/Ho2O3-TNSs (Fe:Ho:Ti = 0.05:1:100), which was 8.86 and 6.72 times than that of individual 1.0%-Ho2O3-TNSs (Ho:Ti = 1:100) and 0.05%-Fe2O3-TNSs (Fe:Ti = 0.05:100), respectively. The possible mechanism for enhanced visible-light-induced photocatalytic activity was proposed. Ho2O3 introduced in the photocatalysts may act as the hole capture while Fe2O3 may share the same Fermi levels with TNSs and serve as the electron capture center in the n-n-p system, which reduced the recombination rate of photo-induced electron-hole pairs.

Clinical effects of transcatheter hepatic arterial embolization with holmium-166 poly(l-lactic acid) microspheres in healthy pigs

PubMed Central

Nijsen, J. F. W.; de Wit, T. C.; Seppenwoolde, J. H.; Krijger, G. C.; Seevinck, P. R.; Huisman, A.; Zonnenberg, B. A.; van den Ingh, T. S. G. A. M.; van het Schip, A. D.

2008-01-01

Purpose The aim of this study is to evaluate the toxicity of holmium-166 poly(l-lactic acid) microspheres administered into the hepatic artery in pigs. Methods Healthy pigs (20–30 kg) were injected into the hepatic artery with holmium-165-loaded microspheres (165HoMS; n = 5) or with holmium-166-loaded microspheres (166HoMS; n = 13). The microspheres’ biodistribution was assessed by single-photon emission computed tomography and/or MRI. The animals were monitored clinically, biochemically, and (166HoMS group only) hematologically over a period of 1 month (165HoMS group) or over 1 or 2 months (166HoMS group). Finally, a pathological examination was undertaken. Results After microsphere administration, some animals exhibited a slightly diminished level of consciousness and a dip in appetite, both of which were transient. Four lethal adverse events occurred in the 166HoMS group due either to incorrect administration or comorbidity: inadvertent delivery of microspheres into the gastric wall (n = 2), preexisting gastric ulceration (n = 1), and endocarditis (n = 1). AST levels were transitorily elevated post-166HoMS administration. In the other blood parameters, no abnormalities were observed. Nuclear scans were acquired from all animals from the 166HoMS group, and MRI scans were performed if available. In pigs from the 166HoMS group, atrophy of one or more liver lobes was frequently observed. The actual radioactivity distribution was assessed through ex vivo 166mHo measurements. Conclusion It can be concluded that the toxicity profile of HoMS is low. In pigs, hepatic arterial embolization with 166HoMS in amounts corresponding with liver-absorbed doses of over 100 Gy, if correctly administered, is not associated with clinically relevant side effects. This result offers a good perspective for upcoming patient trials. PMID:18330569

Radical production from photosensitization of imidazoles, benzophenone and 4-benzoylbenzoic acid

NASA Astrophysics Data System (ADS)

Corral Arroyo, Pablo; González, Laura; Steimer, Sarah; Volkamer, Rainer; George, Christian; Bartels-Rausch, Thorsten; Ammann, Markus

2016-04-01

Reactions promoted by light are key in atmospheric chemistry. Some of them occur in the condensed phase of aerosols which may contain light absorbing organic compounds that provoke photochemical reactions such as humic like material (GEORGE 2005). Our aim is to understand the role these reactions play in atmospheric photochemistry. This work explores the radical reactions initiated by UV light in mixtures of citric acid (CA) and imidazole-2-carboxaldehyde (IC), benzophenone and 4-Benzoylbenzoic acid (BBA) using NO as a probe molecule for HO2, by means of coated wall flow tube experiments. The loss of NO was measured by a chemiluminescence detector (CLD), also configured for the distinction of the products (HONO or NO2). The dependence of the NO loss on the initial NO concentration, the photosensitizer concentration in the film, relative humidity, light intensity, oxygen molar fraction were investigated as well as the HONO and NO2 yields. We found a clear correlation between the loss of NO above the film and the molar ratio of photosensitizer/CA, and also between the NO loss and the light intensity. The variation of the observed NO loss with oxygen corroborates a mechanism, in which the triplet excited state of the photosensitizer is reduced likely by the predominant donor in the system, citric acid, to a reduced ketyl radical. This reactive species is transferring an electron to molecular oxygen, which in turn leads to production of HO2 radicals, which are released to the gas phase. Therefore, in absence of gas phase oxidants, the loss of NO in the gas phase could be related to the production of HO2 radicals in the condensed phase. Relative humidity had a strong impact on the HO2 output, which shows a maximum value at intermediate humidity around 30%, likely due to different competing effects of dilution and reactant mobility. The observed NO2/HONO ratio was around 1.4 consistent with the secondary chemistry of HO2 in presence of NO in the gas phase, indicating no additional direct release of OH to the gas phase nor direct conversion of NO2 to HONO at the film surface. IC and BBA showed similar HO2 production rates, while the HO2 yield with benzophenone was around 50 times higher. We could preliminary quantify for the first time the contribution of these processes to the oxidative capacity in the atmosphere and conclude that their role is significant for aerosol aging. References George, C., Strekowski, R. S., Kleffmann, J., Stemmler, K., and Ammann, M.: Photoenhanced uptake of gaseous NO2 on solid organic compounds: a photochemical source of HONO?, Faraday Discussions, 130, 195, 2005.

Iron depletion in HCT116 cells diminishes the upregulatory effect of phenethyl isothiocyanate on heme oxygenase-1

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

Bolloskis, Michael P.; Carvalho, Fabiana P.; Loo, George, E-mail: g_loo@uncg.edu

Some of the health-promoting properties of cruciferous vegetables are thought to be partly attributed to isothiocyanates. These phytochemicals can upregulate the expression of certain cytoprotective stress genes, but it is unknown if a particular nutrient is involved. Herein, the objective was to ascertain if adequate iron is needed for enabling HCT116 cells to optimally express heme oxygenase-1 (HO-1) when induced by phenethyl isothiocyanate (PEITC). PEITC increased HO-1 expression and also nuclear translocation of Nrf2, which is a transcription factor known to activate the HO-1 gene. However, in HCT116 cells that were made iron-deficient by depleting intracellular iron with deferoxamine (DFO),more » PEITC was less able to increase HO-1 expression and nuclear translocation of Nrf2. These suppressive effects of DFO were overcome by replenishing the iron-deficient cells with the missing iron. To elucidate these findings, it was found that PEITC-induced HO-1 upregulation can be inhibited with thiol antioxidants (glutathione and N-acetylcysteine). Furthermore, NADPH oxidase inhibitors (diphenyleneiodonium and apocynin) and a superoxide scavenger (Tiron) each inhibited PEITC-induced HO-1 upregulation. In doing so, diphenyleneiodonium was the most potent and also inhibited nuclear translocation of redox-sensitive Nrf2. Collectively, the results imply that the HO-1 upregulation by PEITC involves an iron-dependent, oxidant signaling pathway. Therefore, it is concluded that ample iron is required to enable PEITC to fully upregulate HO-1 expression in HCT116 cells. As such, it is conceivable that iron-deficient individuals may not reap the full health benefits of eating PEITC-containing cruciferous vegetables that via HO-1 may help protect against multiple chronic diseases. - Highlights: • PEITC increased HO-1 expression in HCT116 cells. • PEITC-induced HO-1 upregulation was impaired in iron-depleted HCT116 cells. • Impairment of PEITC-induced HO-1 upregulation was reversible with iron restoration. • PEITC increased nuclear expression of Nrf2 but not in iron-depleted cells. • NADPH oxidase inhibitors inhibited PEITC-induced HO-1 upregulation.« less

Structure, upconversion photoluminescence, and dielectric properties of Ho{sup 3+}- and Yb{sup 3+}-codoped tetragonal tungsten bronze Sr{sub 4}La{sub 2}Ti{sub 4}Nb{sub 6}O{sub 30}

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

Wei, T., E-mail: weitong.nju@gmail.com; Li, C.P.; Zhou, Q.J.

2015-04-15

Highlights: • TTB-type SLTN: Ho-Ybx with space group P4/mbm was determined. • UC photoluminescence of SLTN: Ho-Ybx ceramics was first reported. • Bright UC green emission was observed at room temperature. • Two-photon energy transfer process was confirmed for the UC processes. • Temperature stability of dielectric permittivity was improved for SLTN: Ho-Ybx. - Abstract: Ho{sup 3+}- and Yb{sup 3+}-codoped Sr{sub 4}La{sub 2}Ti{sub 4}Nb{sub 6}O{sub 30} (Sr{sub 4}La{sub 1.94–x}Ho{sub 0.06}Yb{sub x}Ti{sub 4}Nb{sub 6}O{sub 30}, abbreviated as SLTN: Ho-Ybx) ceramics have been synthesized, and their structural, up-conversion (UC) photoluminescence, and dielectric properties have been carefully investigated. Through Rietveld structural refinement, SLTN:more » Ho-Ybx samples are determined as single tetragonal tungsten bronze (TTB) phase with space group P4/mbm in which larger Sr{sup 2+} ions fill the A{sub 2}-sites, relative smaller La{sup 3+}, Ho{sup 3+}, and Yb{sup 3+} ions occupy the A{sub 1}-sites, while Ti{sup 4+} and Nb{sup 4+} ions fill the B-sites. Under 980 nm near infrared (NIR) excitation, bright UC green emission, relatively weak red and near-infrared (NIR) emissions, originating from {sup 5}F{sub 4}/{sup 5}S{sub 2} → {sup 5}I{sub 8}, {sup 5}F{sub 5} → {sup 5}I{sub 8}, and {sup 5}F{sub 4}/{sup 5}S{sub 2} → {sup 5}I{sub 7} transitions of Ho{sup 3+} ions, are confirmed for SLTN: Ho-Ybx. Two-photon energy transfer process is proved through pumping laser power dependence of emission intensity measurement. Furthermore, the influence of Ho{sup 3+}- and Yb{sup 3+}- ions on the dielectric properties of SLTN: Ho-Ybx is also investigated and the temperature stability of dielectric permittivity is improved.« less

Spectroscopic studies reveal that the heme regulatory motifs of heme oxygenase-2 are dynamically disordered and exhibit redox-dependent interaction with heme

DOE PAGES

Bagai, Ireena; Sarangi, Ritimukta; Fleischhacker, Angela S.; ...

2015-05-05

Heme oxygenase (HO) catalyzes a key step in heme homeostasis: the O₂₋ and NADPH-cytochrome P450 reductase-dependent conversion of heme to biliverdin, Fe, and CO through a process in which the heme participates both as a prosthetic group and as a substrate. Mammals contain two isoforms of this enzyme, HO2 and HO1, which share the same α-helical fold forming the catalytic core and heme binding site, as well as a membrane spanning helix at their C-termini. However, unlike HO1, HO2 has an additional 30-residue N-terminus as well as two cysteine-proline sequences near the C-terminus that reside in heme regulatory motifs (HRMs).more » While the role of the additional N-terminal residues of HO2 is not yet understood, the HRMs have been proposed to reversibly form a thiol/disulfide redox switch that modulates the affinity of HO2 for ferric heme as a function of cellular redox poise. To further define the roles of the N- and C-terminal regions unique to HO2, we used multiple spectroscopic techniques to characterize these regions of the human HO2. Nuclear magnetic resonance spectroscopic experiments with HO2 demonstrate that, when the HRMs are in the oxidized state (HO2 O), both the extra N-terminal and the C-terminal HRM-containing regions are disordered. However, protein NMR experiments illustrate that, under reducing conditions, the C-terminal region gains some structure as the Cys residues in the HRMs undergo reduction (HO2 R) and, in experiments employing a diamagnetic protoporphyrin, suggest a redox-dependent interaction between the core and the HRM domains. Further, electron nuclear double resonance and X-ray absorption spectroscopic studies demonstrate that, upon reduction of the HRMs to the sulfhydryl form, a cysteine residue from the HRM region ligates to a ferric heme. Taken together with EPR measurements, which show the appearance of a new low-spin heme signal in reduced HO2, it appears that a cysteine residue(s) in the HRMs directly interacts with a second bound heme.« less

Transduction of PEP-1-heme oxygenase-1 into insulin-producing INS-1 cells protects them against cytokine-induced cell death

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

Lee, Su Jin; Kang, Hyung Kyung; Song, Dong Keun

Pro-inflammatory cytokines play a crucial role in the destruction of pancreatic β-cells, thereby triggering the development of autoimmune diabetes mellitus. We recently developed a cell-permeable fusion protein, PEP-1-heme oxygenase-1 (PEP-1-HO-1) and investigated the anti-inflammatory effects in macrophage cells. In this study, we transduced PEP-1-HO-1 into INS-1 insulinoma cells and examined its protective effect against cytokine-induced cell death. PEP-1-HO-1 was successfully delivered into INS-1 cells in time- and dose-dependent manner and was maintained within the cells for at least 48 h. Pre-treatment with PEP-1-HO-1 increased the survival of INS-1 cells exposed to cytokine mixture (IL-1β, IFN-γ, and TNF-α) in a dose-dependent manner.more » PEP-1-HO-1 markedly decreased cytokine-induced production of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA). These protective effects of PEP-1-HO-1 against cytokines were correlated with the changes in the levels of signaling mediators of inflammation (iNOS and COX-2) and cell apoptosis/survival (Bcl-2, Bax, caspase-3, PARP, JNK, and Akt). These results showed that the transduced PEP-1-HO-1 efficiently prevented cytokine-induced cell death of INS-1 cells by alleviating oxidative/nitrosative stresses and inflammation. Further, these results suggested that PEP-1-mediated HO-1 transduction may be a potential therapeutic strategy to prevent β-cell destruction in patients with autoimmune diabetes mellitus. - Highlights: • We showed that PEP-1-HO-1 was efficiently delivered into INS-1 cells. • Transduced PEP-1-HO-1 exerted a protective effect against cytokine-induced cell death. • Transduced PEP-1-HO-1 inhibited cytokine-induced ROS and NO accumulation. • PEP-1-HO-1 suppressed cytokine-induced expression of iNOS, COX-2, and Bax. • PEP-1-HO-1 transduction may be an efficient tool to prevent β-cell destruction.« less

Spectroscopic studies reveal that the heme regulatory motifs of heme oxygenase-2 are dynamically disordered and exhibit redox-dependent interaction with heme

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

Bagai, Ireena; Sarangi, Ritimukta; Fleischhacker, Angela S.

Heme oxygenase (HO) catalyzes a key step in heme homeostasis: the O₂₋ and NADPH-cytochrome P450 reductase-dependent conversion of heme to biliverdin, Fe, and CO through a process in which the heme participates both as a prosthetic group and as a substrate. Mammals contain two isoforms of this enzyme, HO2 and HO1, which share the same α-helical fold forming the catalytic core and heme binding site, as well as a membrane spanning helix at their C-termini. However, unlike HO1, HO2 has an additional 30-residue N-terminus as well as two cysteine-proline sequences near the C-terminus that reside in heme regulatory motifs (HRMs).more » While the role of the additional N-terminal residues of HO2 is not yet understood, the HRMs have been proposed to reversibly form a thiol/disulfide redox switch that modulates the affinity of HO2 for ferric heme as a function of cellular redox poise. To further define the roles of the N- and C-terminal regions unique to HO2, we used multiple spectroscopic techniques to characterize these regions of the human HO2. Nuclear magnetic resonance spectroscopic experiments with HO2 demonstrate that, when the HRMs are in the oxidized state (HO2 O), both the extra N-terminal and the C-terminal HRM-containing regions are disordered. However, protein NMR experiments illustrate that, under reducing conditions, the C-terminal region gains some structure as the Cys residues in the HRMs undergo reduction (HO2 R) and, in experiments employing a diamagnetic protoporphyrin, suggest a redox-dependent interaction between the core and the HRM domains. Further, electron nuclear double resonance and X-ray absorption spectroscopic studies demonstrate that, upon reduction of the HRMs to the sulfhydryl form, a cysteine residue from the HRM region ligates to a ferric heme. Taken together with EPR measurements, which show the appearance of a new low-spin heme signal in reduced HO2, it appears that a cysteine residue(s) in the HRMs directly interacts with a second bound heme.« less

The induction of heme oxygenase-1 suppresses heat shock protein 90 and the proliferation of human breast cancer cells through its byproduct carbon monoxide

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

Lee, Wen-Ying; Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Chen, Yen-Chou

2014-01-01

Heme oxygenase (HO)-1 is an oxidative stress-response enzyme which catalyzes the degradation of heme into bilirubin, ferric ion, and carbon monoxide (CO). Induction of HO-1 was reported to have antitumor activity; the inhibitory mechanism, however, is still unclear. In the present study, we found that treatment with [Ru(CO){sub 3}Cl{sub 2}]{sub 2} (RuCO), a CO-releasing compound, reduced the growth of human MCF7 and MDA-MB-231 breast cancer cells. Analysis of growth-related proteins showed that treatment with RuCO down-regulated cyclinD1, CDK4, and hTERT protein expressions. Interestingly, RuCO treatment resulted in opposite effects on wild-type and mutant p53 proteins. These results were similar tomore » those of cells treated with geldanamycin (a heat shock protein (HSP)90 inhibitor), suggesting that RuCO might affect HSP90 activity. Moreover, RuCO induced mutant p53 protein destabilization accompanied by promotion of ubiquitination and proteasome degradation. The induction of HO-1 by cobalt protoporphyrin IX (CoPP) showed consistent results, while the addition of tin protoporphyrin IX (SnPP), an HO-1 enzymatic inhibitor, diminished the RuCO-mediated effect. RuCO induction of HO-1 expression was reduced by a p38 mitogen-activated protein kinase inhibitor (SB203580). Additionally, treatment with a chemopreventive compound, curcumin, induced HO-1 expression accompanied with reduction of HSP90 client protein expression. The induction of HO-1 by curcumin inhibited 12-O-tetradecanoyl-13-acetate (TPA)-elicited matrix metalloproteinase-9 expression and tumor invasion. In conclusion, we provide novel evidence underlying HO-1's antitumor mechanism. CO, a byproduct of HO-1, suppresses HSP90 protein activity, and the induction of HO-1 may possess potential as a cancer therapeutic. - Highlights: • CO and HO-1 inhibited the growth of human breast cancer cells. • CO and HO-1 attenuated HSP90 and its client proteins expression. • CO induced mutant p53 protein ubiquitination and degradation. • Curcumin induced HO-1 expression and attenuated HSP90's client proteins expression.« less

L-Ascorbate attenuates methamphetamine neurotoxicity through enhancing the induction of endogenous heme oxygenase-1

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

Huang, Ya-Ni; Wang, Jiz-Yuh; Lee, Ching-Tien

Methamphetamine (METH) is a drug of abuse which causes neurotoxicity and increased risk of developing neurodegenerative diseases. We previously found that METH induces heme oxygenase (HO)-1 expression in neurons and glial cells, and this offers partial protection against METH toxicity. In this study, we investigated the effects of L-ascorbate (vitamin C, Vit. C) on METH toxicity and HO-1 expression in neuronal/glial cocultures. Cell viability and damage were evaluated by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release, respectively. Neuronal and glial localization of HO-1 were identified by double immunofluorescence staining. Reactive oxygen species (ROS) production was measuredmore » using the fluorochrome 2′,7′-dichlorofluorescin diacetate. HO-1 mRNA and protein expression were examined by RT-qPCR and Western blotting, respectively. Results show that Vit. C induced HO-1 mRNA and protein expressions in time- and concentration-dependent manners. Inhibition of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase (ERK) significantly blocked induction of HO-1 by Vit. C. HO-1 mRNA and protein expressions were significantly elevated by a combination of Vit. C and METH, compared to either Vit. C or METH alone. Pretreatment with Vit. C enhanced METH-induced HO-1 expression and attenuated METH-induced ROS production and neurotoxicity. Pharmacological inhibition of HO activity abolished suppressive effects of Vit. C on METH-induced ROS production and attenuated neurotoxicity. We conclude that induction of HO-1 expression contributes to the attenuation of METH-induced ROS production and neurotoxicity by Vit. C. We suggest that HO-1 induction by Vit. C may serve as a strategy to alleviate METH neurotoxicity. -- Highlights: ► Besides the anti-oxidant effect, Vit. C also induces HO-1 expression in brain cells. ► Vit. C reduces METH neurotoxicity and ROS production by upregulating HO-1 expression. ► These results suggest a therapeutic potential for Vit. C in treating METH abusers.« less

Heme Oxygenase-1 Gene Therapy Provides Cardioprotection Via Control of Post-Ischemic Inflammation: An Experimental Study in a Pre-Clinical Pig Model.

PubMed

Hinkel, Rabea; Lange, Philipp; Petersen, Björn; Gottlieb, Elena; Ng, Judy King Man; Finger, Stefanie; Horstkotte, Jan; Lee, Seungmin; Thormann, Michael; Knorr, Maike; El-Aouni, Chiraz; Boekstegers, Peter; Reichart, Bruno; Wenzel, Philip; Niemann, Heiner; Kupatt, Christian

2015-07-14

Heme oxygenase-1 (HO-1) is an inducible stress-responsive enzyme converting heme to bilirubin, carbon monoxide, and free iron, which exerts anti-inflammatory and antiapoptotic effects. Although efficient cardioprotection after HO-1 overexpression has been reported in rodents, its role in attenuating post-ischemic inflammation is unclear. This study assessed the efficacy of recombinant adenoassociated virus (rAAV)-encoding human heme oxygenase-1 (hHO-1) in attenuating post-ischemic inflammation in a murine and a porcine ischemia/reperfusion model. Murine ischemia was induced by 45 min of left anterior descending occlusion, followed by 24 h of reperfusion and functional as well as fluorescent-activated cell sorting analysis. Porcine hearts were subjected to 60 min of ischemia and 24h of reperfusion before hemodynamic and histologic analyses were performed. Human microvascular endothelial cells transfected with hHO-1 displayed an attenuated interleukin-6 and intercellular adhesion molecule 1 expression, resulting in reduced monocytic THP-1 cell recruitment in vitro. In murine left anterior descending occlusion and reperfusion, the post-ischemic influx of CD45(+) leukocytes, Ly-6G(+) neutrophils, and Ly-6C(high) monocytes was further exacerbated in HO-1-deficient hearts and reversed by rAAV.hHO-1 treatment. Conversely, in our porcine model of ischemia, the post-ischemic influx of myeloperoxidase-positive neutrophils and CD14(+) monocytes was reduced by 49% and 87% after rAAV.hHO-1 transduction, similar to hHO-1 transgenic pigs. Functionally, rAAV.hHO-1 and hHO-1 transgenic left ventricles displayed a smaller loss of ejection fraction than control animals. Whereas HO-1 deficiency exacerbates post-ischemic cardiac inflammation in mice, hHO-1 gene therapy attenuates inflammation after ischemia and reperfusion in murine and porcine hearts. Regional hHO-1 gene therapy provides cardioprotection in a pre-clinical porcine ischemia/reperfusion model. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

High-power dual-wavelength Ho-doped fiber laser at >2 μm tandem pumped by a 1.15 μm fiber laser

PubMed Central

Jin, Xiaoxi; Lou, Zhaokai; Chen, Yizhu; Zhou, Pu; Zhang, Hanwei; Xiao, Hu; Liu, Zejin

2017-01-01

We demonstrated a high-power continuous-wave (CW) dual-wavelength Ho-doped fiber laser (HDFL) at 2049 nm and 2153 nm with a simple coupled-cavity configuration. A ~100 W laser diode-pumped fiber laser at 1150 nm served as the pump source. The maximum output power reached ~22.3 W and the slope efficiency was 23%. By altering the incident pump power, the power ratio of two signal wavelengths could be tuned in a large range due to gain competition. As far as we know, this is the first CW dual-wavelength HDFL with the power exceeding ten-watt-level, and the first dual-wavelength HDFL with the central wavelengths exceeding 2.0 μm and 2.15 μm respectively. PMID:28181571

High-power dual-wavelength Ho-doped fiber laser at >2 μm tandem pumped by a 1.15 μm fiber laser

NASA Astrophysics Data System (ADS)

Jin, Xiaoxi; Lou, Zhaokai; Chen, Yizhu; Zhou, Pu; Zhang, Hanwei; Xiao, Hu; Liu, Zejin

2017-02-01

We demonstrated a high-power continuous-wave (CW) dual-wavelength Ho-doped fiber laser (HDFL) at 2049 nm and 2153 nm with a simple coupled-cavity configuration. A ~100 W laser diode-pumped fiber laser at 1150 nm served as the pump source. The maximum output power reached ~22.3 W and the slope efficiency was 23%. By altering the incident pump power, the power ratio of two signal wavelengths could be tuned in a large range due to gain competition. As far as we know, this is the first CW dual-wavelength HDFL with the power exceeding ten-watt-level, and the first dual-wavelength HDFL with the central wavelengths exceeding 2.0 μm and 2.15 μm respectively.

High-resolution angle-resolved photoemission study of electronic structure and charge-density wave formation in HoTe3

NASA Astrophysics Data System (ADS)

Liu, Guodong; Wang, Chenlu; Zhang, Yan; Hu, Bingfeng; Mou, Daixiang; Yu, Li; Zhao, Lin; Zhou, Xingjiang; Wang, Nanlin; Chen, Chuangtian; Xu, Zuyan

We performed high-resolution angle-resolved photoemission spectroscopy (ARPES) measurement on high quality crystal of HoTe3, an intriguing quasi-two-dimensional rare-earth-element tritelluride charge-density-wave (CDW) compound. The main features of the electronic structure in this compound are established by employing a quasi-CW laser (7eV) and a helium discharging lamp (21.22 eV) as excitation light sources. It reveals many bands back folded according to the CDW periodicity and two incommensurate CDW gaps created by perpendicular Fermi surface (FS) nesting vectors. A large gap is found to open in well nested regions of the Fermi surface sheets, whereas other Fermi surface sections with poor nesting remain ungapped. In particular, some peculiar features are identified by using our ultra-high resolution and bulk sensitive laser-ARPES.

Induction of HO-1 by carbon monoxide releasing molecule-2 attenuates thrombin-induced COX-2 expression and hypertrophy in primary human cardiomyocytes

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

Chien, Peter Tzu-Yu; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan, Taiwan; Lin, Chih-Chung

Carbon monoxide (CO) is one of the cytoprotective byproducts of heme oxygenase (HO)-1 and exerts anti-inflammatory action in various models. However, the detailed mechanisms underlying CO-induced HO-1 expression in primary human cardiomyocytes remain largely unidentified. We used primary left ventricle myocytes as a model and applied CO releasing molecule (CORM)-2 to investigate the relationship of CO and HO-1 expression. We herein used Western blot, real-time PCR, promoter activity and EIA to investigate the role of HO-1 expression protecting against thrombin-mediated responses. We found that thrombin-induced COX-2 expression, PGE{sub 2} release and cardiomyocyte hypertrophy markers (increase in ANF/BNP, α-actin expression andmore » cell surface area) was attenuated by pretreatment with CORM-2 which was partially reversed by hemoglobin (Hb) or ZnPP (an inhibitor of HO-1 activity), suggesting that HO-1/CO system may be of clinical importance to ameliorate heart failure through inhibition of inflammatory responses. CORM-2-induced HO-1 protein expression, mRNA and promoter was attenuated by pretreatment with the inhibitors of Pyk2 (PF431396), PDGFR (AG1296), PI3K (LY294002), Akt (SH-5), p38 (SB202530), JNK1/2 (SP600125), FoxO1 (AS1842856) and Sp1 (mithramycin A). The involvement of these signaling components was further confirmed by transfection with respective siRNAs, consistent with those of pharmacological inhibitors. These results suggested that CORM-2-induced HO-1 expression is mediated through a Pyk2/PDGFR/PI3K/Akt/FoxO1/Sp1-dependent manner and exerts a cytoprotective effect in human cardiomyocytes. - Graphical abstract: In summary, CORM-2 treatment induces Pyk2 transactivated PDGFR, which induces PI3K/Akt/MAPK activation, and then recruits Sp1/Foxo1 transcriptional factors to regulate HO-1 gene expression in primary human cardiomyocytes. - Highlights: • CORM-2 induces HO-1 expression. • Pyk2-dependent PDGFR activates PI3K/Akt/MAPK pathway in CORM-2-induced HO-1 expression. • Transcriptional regulation of HO-1 expression is mediated by Sp1/Foxo1. • CO/HO-1 systems ameliorate thrombin-induced human cardiomyocyte hypertrophy.« less

Heme oxygenase-1-mediated apoptosis under cadmium-induced oxidative stress is regulated by autophagy, which is sensitized by tumor suppressor p53

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

So, Keum-Young; Oh, Seon-Hee

Heme oxygenase-1 (HO-1) is a stress-inducible cytoprotective enzyme. It is often overexpressed in different types of cancers and promotes cell survival. However, the role of HO-1 and the underlying molecular mechanism of cadmium (Cd)-induced oxidative stress in cancer cells remain undefined. Here we show that the role of HO-1 under Cd-induced oxidative stress is dependent upon autophagy, which is sensitized by the tumor suppressor p53. The sensitivity to Cd was 3.5- and 14-fold higher in p53-expressing YD8 and H460 cells than in p53-null YD10B and H1299 cells, respectively. The levels of p53 in YD8 and H460 cells decreased in a Cd concentration-dependent manner,more » which was inhibited by pretreatment with N-acetylcysteine. In both cell lines, Cd exposure resulted in caspase-3-mediated PARP-1 cleavage and the induction of CHOP, LC3-II, and HO-1, which were limited in YD10B and H1299 cells exposed to high concentrations of Cd. Cd exposure to p53-overexpressing YD10B cells enhanced Cd-induced HO-1 and LC3-II levels, whereas genetic knockdown of p53 in YD8 cells resulted in the suppression of Cd-induced levels of HO-1 and LC3-II, indicating that p53 is required in the sensing of HO-1 and induction of autophagy. The inhibition of autophagy using small interfering RNA (siRNA) for the autophagy-related gene atg5 enhanced HO-1, CHOP, and PARP-1 cleavage induced by Cd. However, transfection with HO-1 siRNA increased Cd-induced LC3-II, and suppressed the expression of CHOP and cleavage of PARP-1. Collectively, the role of HO-1 in apoptosis could be modulated by autophagy, which is sensitized by p53 expression in human cancer cell lines. - Highlights: • Cadmium exposure decreased p53 level, and induced HO-1, apoptosis, and autophagy. • p53 sensitized Cadmium-induced HO-1 and autophagy induction. • Cadmium induced HO-1 under autophagy impairment and increased apoptosis. • Cadmium-induced autophagy was enhanced under HO-1 impaired conditions. • The role of HO-1 in Cadmium-induced apoptosis is modulated by autophagy.« less

Graphene-immobilized flower-like Ni3S2 nanoflakes as a stable binder-free anode material for sodium-ion batteries

NASA Astrophysics Data System (ADS)

Han, Yu; Liu, Shuang-yu; Cui, Lei; Xu, Li; Xie, Jian; Xia, Xue-Ke; Hao, Wen-Kui; Wang, Bo; Li, Hui; Gao, Jie

2018-01-01

A binder-free Ni3S2 electrode was prepared directly on a graphene-coated Ni foam (G/Ni) substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni3S2 showed a flower-like morphology and was uniformly distributed on the G/Ni surface. The flower-like Ni3S2 was composed of cross-arrayed nanoflakes with a diameter and a thickness of 1-2 μm and 50 nm, respectively. The free space in the flowers and the thin feature of Ni3S2 buffered the volume changes and relieved mechanical strain during repeated cycling. The intimate contact with the Ni substrate and the fixing effect of graphene maintained the structural stability of the Ni3S2 electrode during cycling. The G/Ni-supported Ni3S2 maintained a reversible capacity of 250 mAh.g-1 after 100 cycles at 50 mA.g-1, demonstrating the good cycling stability as a result of the unique microstructure of this electrode material.

Synthesis, Crystal Structures, Magnetic Properties, and Theoretical Investigation of a New Series of NiII-LnIII-WV Heterotrimetallics: Understanding the SMM Behavior of Mixed Polynuclear Complexes.

PubMed

Vieru, Veacheslav; Pasatoiu, Traian D; Ungur, Liviu; Suturina, Elizaveta; Madalan, Augustin M; Duhayon, Carine; Sutter, Jean-Pascal; Andruh, Marius; Chibotaru, Liviu F

2016-12-05

The polynuclear compounds containing anisotropic metal ions often exhibit efficient barriers for blocking of magnetization at fairly arbitrary geometries. However, at variance with mononuclear complexes, which usually become single-molecule magnets (SMM) under the sole requirement of a highly axial crystal field at the metal ion, the factors influencing the SMM behavior in polynuclear complexes, especially, with weakly axial magnetic ions, still remain largely unrevealed. As an attempt to clarify these conditions, we present here the synthesis, crystal structures, magnetic behavior, and ab initio calculations for a new series of Ni II -Ln III -W V trimetallics, [(CN) 7 W(CN)Ni(H 2 O)(valpn)Ln(H 2 O) 4 ]·H 2 O (Ln = Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Lu 6). The surprising finding is the absence of the magnetic blockage even for compounds involving strongly anisotropic Dy III and Tb III metal ions. This is well explained by ab initio calculations showing relatively large transversal components of the g-tensor in the ground exchange Kramers doublets of 1 and 4 and large intrinsic tunneling gaps in the ground exchange doublets of 3 and 5. In order to get more insight into this behavior, another series of earlier reported compounds with the same trinuclear [W V Ni II Ln III ] core structure, [(CN) 7 W(CN)Ni(dmf)(valdmpn)Ln(dmf) 4 ]·H 2 O (Ln = Gd III 7, Tb III 8a, Dy III 9, Ho III 10), [(CN) 7 W(CN)Ni(H 2 O)(valdmpn)Tb(dmf) 2.5 (H 2 O) 1.5 ]·H 2 O·0.5dmf 8b, and [(CN) 7 W(CN)Ni(H 2 O)(valdmpn)Er(dmf) 3 (H 2 O) 1 ]·H 2 O·0.5dmf 11, has been also investigated theoretically. In this series, only 8b exhibits SMM behavior which is confirmed by the present ab initio calculations. An important feature for the entire series is the strong ferromagnetic coupling between Ni(II) and W(V), which is due to an almost perfect trigonal dodecahedron geometry of the octacyano wolframate fragment. The reason why only 8b is an SMM is explained by positive zero-field splitting on the nickel site, precluding magnetization blocking in complexes with fewer axial Ln ions. Further analysis has shown that, in the absence of ZFS on Ni ion, all compounds in the two series (except those containing Y and Gd) would be SMMs. The same situation arises for perfectly axial ZFS on Ni(II) with the main anisotropy axis parallel to the main magnetic axis of Ln(III) ions. In all other cases the ZFS on Ni(II) will worsen the SMM properties. The general conclusion is that the design of efficient SMMs on the basis of such complexes should involve isotropic or weekly anisotropic metal ions, such as Mn(II), Fe(III), etc., along with strongly axial lanthanides.

Origin and significance of high nickel and chromium concentrations in pliocene lignite of the Kosovo Basin, Serbia

USGS Publications Warehouse

Ruppert, L.; Finkelman, R.; Boti, E.; Milosavljevic, M.; Tewalt, S.; Simon, N.; Dulong, F.

1996-01-01

Trace element data from 59 Pliocene lignite cores from the lignite field in the Kosovo Basin, southern Serbia, show localized enrichment of Ni and Cr (33-304 ppm and 8-176 ppm, respectively, whole-coal basis). Concentrations of both elements decrease from the western and southern boundaries of the lignite field. Low-temperature ash and polished coal pellets of selected bench and whole-coal samples were analyzed by X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray analyses. These analyses show that most of the Ni and Cr are incorporated in detrital and, to a lesser degree, in authigenic minerals. The Ni- and Cr-bearing detrital minerals include oxides, chromites, serpentine-group minerals and rare mixed-layer clays. Possible authigenic minerals include Ni-Fe sulfates and sulfides. Analyses of three lignite samples by a supercritical fluid extraction technique indicate that some (1-11%) of the Ni is organically bound. Ni- and Cr-bearing oxides, mixed-layer clays, chromites and serpentine-group minerals were also identified in weathered and fresh samples of laterite developed on serpentinized Paleozoic peridotite at the nearby Glavica and C??ikatovo Ni mines. These mines are located along the western and northwestern rim, respectively, of the Kosovo Basin, where Ni contents are highest. The detrital Ni- and Cr-bearing minerals identified in lignite samples from the western part of the Kosovo Basin may have been transported into the paleoswamp by rivers that drained the two Paleocene laterites. Some Ni may have been transported directly into the paleoswamp in solution or, alternatively, Ni may have been leached from detrital minerals by acidic peat water and adsorbed onto organic matter and included into authigenic mineral phases. No minable source of Ni and Cr is known in the southern part of the lignite field; however, the mineral and chemical data from the lignite and associated rocks suggest that such a source area may exist.

A new route for the synthesis of titanium silicalite-1

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

Vasile, Aurelia, E-mail: aurelia_vasile@yahoo.com; Busuioc-Tomoiaga, Alina Maria; Catalysis Research Department, ChemPerformance SRL, Iasi 700337

2012-01-15

Graphical abstract: Well-prepared TS-1 was synthesized by an innovative procedure using inexpensive reagents such as fumed silica and TPABr as structure-directing agent. This is the first time when highly crystalline TS-1 is obtained in basic medium, using sodium hydroxide as HO{sup -} ion source required for the crystallization process. Hydrolysis of titanium source has been prevented by titanium complexation with acetylacetone before structuring gel. Highlights: Black-Right-Pointing-Pointer TS-1 was obtained using cheap reagents as fumed silica and tetrapropylammonium bromide. Black-Right-Pointing-Pointer First time NaOH was used as source of OH{sup -} ions required for crystallization process. Black-Right-Pointing-Pointer The hydrolysis Ti alkoxides wasmore » controlled by Ti complexation with 2,4-pentanedione. -- Abstract: A new and efficient route using inexpensive reagents such as fumed silica and tetrapropylammonium bromide is proposed for the synthesis of titanium silicalite-1. High crystalline titanium silicalite-1 was obtained in alkaline medium, using sodium hydroxide as HO{sup -} ion source required for the crystallization process. Hydrolysis of titanium source with formation of insoluble oxide species was prevented by titanium complexation with before structuring gel. The final solids were fully characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared, ultraviolet-visible diffuse reflectance, Raman and atomic absorption spectroscopies, as well as nitrogen sorption analysis. It was found that a molar ratio Ti:Si of about 0.04 in the initial reaction mixture is the upper limit to which well formed titanium silicalite-1 with channels free of crystalline or amorphous material can be obtained. Above this value, solids with MFI type structure containing both Ti isomorphously substituted in the network and extralattice anatase nanoparticles inside of channels is formed.« less

Minfong Ho: Politics in Prose

ERIC Educational Resources Information Center

Wiggins, Joy L.

2006-01-01

In this article, the author interviews Minfong Ho, an award-winning Thai writer of children's and young adult novels. Ho was born in Burma to Chinese parents in 1951, raised in Singapore and Thailand, educated in Bangkok, Taiwan, and at Cornell University in New York. Ho's first novel, "Sing to the Dawn," won first prize from the Council of…

K2Ho(PO4)(WO4)

PubMed Central

Terebilenko, Katherina V.; Zatovsky, Igor V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.; Shishkin, Oleg V.

2008-01-01

A new compound, dipotassium holmium(III) phosphate(V) tungstate(VI), K2Ho(PO4)(WO4), has been obtained during investigation of the K2O–P2O5–WO3–HoF3 phase system using the flux technique. The compound is isotypic with K2Bi(PO4)(WO4). Its framework structure consists of flat ∞ 2[HoPO4] layers parallel to (100) that are made up of ∞ 1[HoO8] zigzag chains inter­linked via slightly distorted PO4 tetra­hedra. WO4 tetra­hedra are attached above and below these layers, leaving space for the K+ counter-cations. The HoO8, PO4 and WO4 units exhibit 2 symmetry. PMID:21580811

Application of petroleum markers to geochemical and environmental investigations

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

Abu-Elgheit, M.A.; El-Gayar, M.S.; Hegazi, A.H.

1998-01-01

Application of trace-metal and biological markers to geochemical studies has shown that crude oils could be correlated or differentiated according to their geologic age. The V/Ni, V/{Sigma} Ni, Mg, Fe, and pristine to phytane (Pr/Ph) markers were almost uniform in Gulf of Suez crude oils, revealing their same origin, yet showing marked differences in Western Desert crude oils, reflecting varying degrees of their maturity and migrational history. The significance of petroleum markers was extended to monitoring of oil spill sources. Weathering of spills usually renders their source identification questionable by infrared or gas chromatography profiles. Since evaporative loss light petroleummore » fractions does not appreciably affect the high-Molecular Weight components with which trace metals, isoprenoids, hopanes, and steranes are associated, V/Ni, Pr/Ph, m/z 191, and m/z 217 mass chromatogram fragments were found reliable in fingerprinting oil spill sources in Mediterranean waters.« less

Discriminating between pyroxenite and peridotite sources for continental flood basalts (CFB) in southern Africa using olivine chemistry

NASA Astrophysics Data System (ADS)

Howarth, Geoffrey H.; Harris, Chris

2017-10-01

Continental Flood Basalts (CFB) result from voluminous outpourings of magma that often precede continental break-up. Notwithstanding the petrogenetic importance of CFBs, the nature of the mantle source for such magmas is contentious, particularly with regard to picrites with Ni-rich olivine phenocrysts. Previous studies have suggested that Ni-rich olivines associated with plume volcanism in regions of thickened (>90 km) lithosphere are related to either source mineralogy differences (peridotite versus pyroxenite) or change in olivine-melt partitioning due to pressure increase. In order to evaluate these two hypotheses, we present trace element data for olivines from the Karoo CFB Tuli and Mwenezi picrites and the Etendeka CFB Horingbaai/LTZ-L type picrites, all of which erupted in regions of thickened (>90 km) lithosphere in southern Africa. Karoo picrite olivines are Ni-rich, Ca- and Mn-poor, and have low (<1.4) 100*Mn/Fe. These compositions are consistent with a pyroxenitic source. Etendeka Horingbaai/LTZ-L picrite olivines do not show Ni-enrichment, but are characterized by high Al and Cr, and high (>1.4) 100*Mn/Fe, which is more consistent with high temperature melting of a dominantly peridotitic source. We also show that the Karoo and Etendeka olivines are characterized by distinct Mn/Zn ratios of <13 and >15, respectively. In addition, bulk rock geochemical data compilations and previously reported olivine δ18O for Karoo and Etendeka CFBs are discussed in order to further constrain source components based on previously described pyroxenite melt geochemical indices such as MgO-CaO systematics, FeO/MnO, Zn/Fe, and FC3MS (FeO/CaO-3*MgO/SiO2). These geochemical indices suggest a pyroxenite-dominated source for Karoo CFBs as well as for Etendeka ferropicrites whereas a peridotite-dominated source is indicated for Etendeka Horingbaai/LTZ-L type picrites analyzed in this study. Based on our data, Ni-enrichment of olivine in plume-related magmas in regions of thickened lithosphere in southern Africa is not ubiquitous. We therefore suggest that mineralogical variation of the source is a more likely major control of olivine chemistry and parent melt variations for Karoo and Etendeka CFBs. We also show that olivine Mn-Zn correlations are a useful discriminator for source variation and recommend the use of olivine Mn /Zn < 13 for a pyroxenite-dominated source relative to olivine Mn /Zn > 15 for a peridotite-dominated source.

Analytical Study of 90Sr Betavoltaic Nuclear Battery Performance Based on p-n Junction Silicon

NASA Astrophysics Data System (ADS)

Rahastama, Swastya; Waris, Abdul

2016-08-01

Previously, an analytical calculation of 63Ni p-n junction betavoltaic battery has been published. As the basic approach, we reproduced the analytical simulation of 63Ni betavoltaic battery and then compared it to previous results using the same design of the battery. Furthermore, we calculated its maximum power output and radiation- electricity conversion efficiency using semiconductor analysis method.Then, the same method were applied to calculate and analyse the performance of 90Sr betavoltaic battery. The aim of this project is to compare the analytical perfomance results of 90Sr betavoltaic battery to 63Ni betavoltaic battery and the source activity influences to performance. Since it has a higher power density, 90Sr betavoltaic battery yields more power than 63Ni betavoltaic battery but less radiation-electricity conversion efficiency. However, beta particles emitted from 90Sr source could travel further inside the silicon corresponding to stopping range of beta particles, thus the 90Sr betavoltaic battery could be designed thicker than 63Ni betavoltaic battery to achieve higher conversion efficiency.

Study of negative ion transport phenomena in a plasma source

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

Riz, D.; Pamela, J.

1996-07-01

NIETZSCHE (Negative Ions Extraction and Transport ZSimulation Code for HydrogEn species) is a negative ion (NI) transport code developed at Cadarache. This code calculates NI trajectories using a 3D Monte-Carlo technique, taking into account the main destruction processes, as well as elastic collisions (H{sup {minus}}/H{sup +}) and charge exchanges (H{sup {minus}}/H{sup 0}). It determines the extraction probability of a NI created at a given position. According to the simulations, we have seen that in the case of volume production, only NI produced close to the plasma grid (PG) can be extracted. Concerning the surface production, we have studied how NImore » produced on the PG and accelerated by the plasma sheath backward into the source could be extracted. We demonstrate that elastic collisions and charge exchanges play an important role, which in some conditions dominates the magnetic filter effect, which acts as a magnetic mirror. NI transport in various conditions will be discussed: volume/surface production, high/low plasmas density, tent filter/transverse filter. {copyright} {ital 1996 American Institute of Physics.}« less

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

Chen Shuguang, E-mail: hustcsg@sohu.com; Zeng Kai; Li Haibin

Dispersed rhombohedral NiS rods with high aspect ratios and rhombic dodecahedron-like cubic NiS{sub 2} crystals were prepared by solvothermal routes using NiCl{sub 2}.6H{sub 2}O and Na{sub 2}S{sub 2}O{sub 3}.5H{sub 2}O as reagents and ethylenediamine as a solvent, and 3D blossoming flower-like rhombohedral NiS microstructures were synthesized using different sulfur sources of thiourea. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersion spectrometry and selected area electronic diffraction. All the products were pure and had good single crystalline nature. The synthesis parameters were of great importance on the purity and morphology of themore » products. The possible growth mechanisms have been discussed based on the analyses of the effects of sulfur sources and solvent on the crystal structures and detailed configurations of the products. The present work is likely to help the phase-controlled synthesis of other metal chalcogenides. - Graphical abstract: Rhombohedral NiS dispersed rods and 3D flower-like microstructures are evolved from dispersed nucleus and aggregate of nucleus, respectively, and the cross-sections of such rods are in equilateral triangle-like shape. Highlights: > 3D blossoming flower-like r-NiS microstructures are obtained. > Equilateral triangle-like cross-sections of r-NiS rods are observed. > Approach based on XRD analysis to phase-controlled synthesis is presented.« less

Understanding in situ ozone production in the summertime through radical observations and modelling studies during the Clean air for London project (ClearfLo)

NASA Astrophysics Data System (ADS)

Whalley, Lisa K.; Stone, Daniel; Dunmore, Rachel; Hamilton, Jacqueline; Hopkins, James R.; Lee, James D.; Lewis, Alastair C.; Williams, Paul; Kleffmann, Jörg; Laufs, Sebastian; Woodward-Massey, Robert; Heard, Dwayne E.

2018-02-01

Measurements of OH, HO2, RO2i (alkene and aromatic-related RO2) and total RO2 radicals taken during the ClearfLo campaign in central London in the summer of 2012 are presented. A photostationary steady-state calculation of OH which considered measured OH reactivity as the OH sink term and the measured OH sources (of which HO2+ NO reaction and HONO photolysis dominated) compared well with the observed levels of OH. Comparison with calculations from a detailed box model utilising the Master Chemical Mechanism v3.2, however, highlighted a substantial discrepancy between radical observations under lower NOx conditions ([NO] < 1 ppbv), typically experienced during the afternoon hours, and indicated that the model was missing a significant peroxy radical sink; the model overpredicted HO2 by up to a factor of 10 at these times. Known radical termination steps, such as HO2 uptake on aerosols, were not sufficient to reconcile the model-measurement discrepancies alone, suggesting other missing termination processes. This missing sink was most evident when the air reaching the site had previously passed over central London to the east and when elevated temperatures were experienced and, hence, contained higher concentrations of VOCs. Uncertainties in the degradation mechanism at low NOx of complex biogenic and diesel related VOC species, which were particularly elevated and dominated OH reactivity under these easterly flows, may account for some of the model-measurement disagreement. Under higher [NO] (> 3 ppbv) the box model increasingly underpredicted total [RO2]. The modelled and observed HO2 were in agreement, however, under elevated NO concentrations ranging from 7 to 15 ppbv. The model uncertainty under low NO conditions leads to more ozone production predicted using modelled peroxy radical concentrations ( ˜ 3 ppbv h-1) versus ozone production from peroxy radicals measured ( ˜ 1 ppbv h-1). Conversely, ozone production derived from the predicted peroxy radicals is up to an order of magnitude lower than from the observed peroxy radicals as [NO] increases beyond 7 ppbv due to the model underprediction of RO2 under these conditions.

Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

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

Kim, Saewung; Kim, So-Young; Lee, Meehye

Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Gangzhou, and Beijing are surrounded by densely forested areas and recent research has consistently demonstrated the importance of biogenic volatile organic compounds from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical concentrations, undermine our ability to assess regional photochemical air pollution problems. We present an observational dataset of CO, NOX, SO2, ozone, HONO, andmore » VOCs (anthropogenic and biogenic) from Taehwa Research Forest (TRF) near the Seoul Metropolitan Area (SMA) in early June 2012. The data show that TRF is influenced both by aged pollution and fresh BVOC emissions. With the dataset, we diagnose HOx (OH, HO2, and RO2) distributions calculated with the University of Washington Chemical Box Model (UWCM v 2.1). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that 1) different model simulation scenarios cause systematic differences in HOX distributions especially OH levels (up to 2.5 times) and 2) radical destruction (HO2+HO2 or HO2+RO2) could be more efficient than radical recycling (HO2+NO) especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone-VOC-NOX sensitivity and oxidation product formation rates. Overall, the VOC limited regime in ozone photochemistry is predicted but the degree of sensitivity can significantly vary depending on the model scenarios. The model results also suggest that RO2 levels are positively correlated with OVOCs production that is not routinely constrained by observations. These unconstrained OVOCs can cause higher than expected OH loss rates (missing OH reactivity) and secondary organic aerosol formation. The series of modeling experiments constrained by observations strongly urge observational constraint of the radical pool to enable precise understanding of regional photochemical pollution problems in the East Asian megacity region.« less

Exploring the Relationship Between Octane Sensitivity and Heat-of-Vaporization

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

Sluder, C. Scott; Szybist, James P.; McCormick, Robert L.

2016-04-05

The latent heat-of-vaporization (HoV) of blends of biofuel and hydrocarbon components into gasolines has recently experienced expanded interest because of the potential for increased HoV to increase fuel knock resistance in direct-injection (DI) engines. Several studies have been conducted, with some studies identifying an additional anti-knock benefit from HoV and others failing to arrive at the same conclusion. Consideration of these studies holistically shows that they can be grouped according to the level of fuel octane sensitivity variation within their fuel matrices. When comparing fuels of different octane sensitivity significant additional anti-knock benefits associated with HoV are sometimes observed. Studiesmore » that fix the octane sensitivity find that HoV does not produce additional anti-knock benefit. New studies were performed at ORNL and NREL to further investigate the relationship between HoV and octane sensitivity. Three fuels were formulated for the ORNL study with matched RON and octane sensitivity, but with differing HoV. Experiments with these fuels in a 1.6-liter GTDI engine showed that the fuels exhibited very similar combustion phasing under knock-limited spark advance (KLSA) conditions. Fuels having a range of RON, octane sensitivity, and HoV were tested at NREL in a single-cylinder GDI engine under conditions where octane sensitivity has little effect on knock resistance. KLSA was found to be well correlated with RON. These results reinforce the concept that HoV anti-knock effects can be viewed as a contributor to octane sensitivity. From this viewpoint, HoV effects manifest themselves as increases in octane sensitivity.« less

Enhancement of red upconversion emission of cubic phase NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanocrystals

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

Gao, Wei, E-mail: gaowei@xupt.edu.com; Dong, Jun, E-mail: dongjun@xupt.edu.cn; Liu, Jihong

Highlights: • The upconversion emission of Ho{sup 3+} ions was tuned from green to red. • The upconversion mechanism of Ho{sup 3+} ions was discussed based on emission spectrum. • The conversion efficiency between Ho{sup 3+} and Ce{sup 3+} were studied and calculated. - Abstract: The red upconversion emission of lanthanide-doped fluoride nanocrystals have great potential applications in color display and anticounterfeiting applications, especially for biological imaging and biomedical. In this work, a significant enhancement of red upconversion emission of Ho{sup 3+} ions was successfully obtained in the cubic phase NaLuF{sub 4} nanocrystals through codoping Ce{sup 3+} ions under NIRmore » 980 nm excitation. The ratio of red-to-green emission of Ho{sup 3+} ions was enhanced about 10-fold, which is due to two efficient cross relaxation processes derived from Ho{sup 3+} and Ce{sup 3+} ions promoted the red emission and quenched the green emission. The upconversion emission and luminescent colors of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} nanocrystals were carefully investigated by a confocal microscopy setup. The possible upconversion emission mechanism and conversion efficiency of cross relaxation between Ho{sup 3+} and Ce{sup 3+} ions were discussed in detail. The current study suggests that strong red emission of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanomaterials can be used for color display and anticounterfeiting techniques.« less

Influence of transcutaneous electrical stimulation on heterotopic ossification: an experimental study in Wistar rats

PubMed Central

Zotz, T.G.G.; de Paula, J.B.

2015-01-01

Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues, resulting in joint mobility deficit and pain. Different treatment modalities have been tried to prevent HO development, but there is no consensus on a therapeutic approach. Since electrical stimulation is a widely used resource in physiotherapy practice to stimulate joint mobility, with analgesic and anti-inflammatory effects, its usefulness for HO treatment was investigated. We aimed to identify the influence of electrical stimulation on induced HO in Wistar rats. Thirty-six male rats (350-390 g) were used, and all animals were anesthetized for blood sampling before HO induction, to quantify the serum alkaline phosphatase. HO induction was performed by bone marrow implantation in both quadriceps of the animals, which were then divided into 3 groups: control (CG), transcutaneous electrical nerve stimulation (TENS) group (TG), and functional electrical stimulation (FES) group (FG) with 12 rats each. All animals were anesthetized and electrically stimulated twice per week, for 35 days from induction day. After this period, another blood sample was collected and quadriceps muscles were bilaterally removed for histological and calcium analysis and the rats were killed. Calcium levels in muscles showed significantly lower results when comparing TG and FG (P<0.001) and between TG and CG (P<0.001). Qualitative histological analyses confirmed 100% HO in FG and CG, while in TG the HO was detected in 54.5% of the animals. The effects of the muscle contractions caused by FES increased HO, while anti-inflammatory effects of TENS reduced HO. PMID:26292223

Methamphetamine induces heme oxygenase-1 expression in cortical neurons and glia to prevent its toxicity

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

Huang, Y.-N.; Wu, C.-H.; Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan 114

2009-11-01

The impairment of cognitive and motor functions in humans and animals caused by methamphetamine (METH) administration underscores the importance of METH toxicity in cortical neurons. The heme oxygenase-1 (HO-1) exerts a cytoprotective effect against various neuronal injures; however, it remains unclear whether HO-1 is involved in METH-induced toxicity. We used primary cortical neuron/glia cocultures to explore the role of HO-1 in METH-induced toxicity. Exposure of cultured cells to various concentrations of METH (0.1, 0.5, 1, 3, 5, and 10 mM) led to cytotoxicity in a concentration-dependent manner. A METH concentration of 5 mM, which caused 50% of neuronal death andmore » glial activation, was chosen for subsequent experiments. RT-PCR and Western blot analysis revealed that METH significantly induced HO-1 mRNA and protein expression, both preceded cell death. Double and triple immunofluorescence staining further identified HO-1-positive cells as activated astrocytes, microglia, and viable neurons, but not dying neurons. Inhibition of the p38 mitogen-activated protein kinase pathway significantly blocked HO-1 induction by METH and aggravated METH neurotoxicity. Inhibition of HO activity using tin protoporphyrine IX significantly reduced HO activity and exacerbated METH neurotoxicity. However, prior induction of HO-1 using cobalt protoporphyrine IX partially protected neurons from METH toxicity. Taken together, our results suggest that induction of HO-1 by METH via the p38 signaling pathway may be protective, albeit insufficient to completely protect cortical neurons from METH toxicity.« less

Low temperature X-ray structure analyses combined with NBO studies of a new heteroleptic octa-coordinated Holmium(III) complex with N,N,N-tridentate hydrazono-phthalazine-type ligand

NASA Astrophysics Data System (ADS)

Soliman, Saied M.; El-Faham, Ayman

2018-04-01

The new heteroleptic [HoL(H2O)5]Br3 complex, L is hydrazono-phthalazine ligand, is synthesized and its molecular structure aspects were analyzed using single crystal X-ray structure (SCXRD), Hirshfeld (HF) analysis, quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) method. The SCXRD showed that the Ho is octa-coordinated with one N,N,N-tridentate ligand L and five water molecules. The HF analysis is used to analyze the molecular packing in the [HoL(H2O)5]Br3crystal structure. The complex cations are connected via strong Osbnd H⋯Br and Nsbnd H⋯Br H-bonding interactions which have greater importance than the Csbnd H⋯Br contacts. Also, all the Hosbnd N and Hosbnd O bonds have the characteristics of closed shell interactions using QTAIM. The natural orbitals included in these interactions were analyzed using NBO method. The alpha LP*(8)Ho and beta LP*(4)Ho which have mainly s-orbital characters are the most important anti-bonding natural orbitals included in all Ho-N and Hosbnd O bonds. The rest of the Ho anti-bonding orbitals which have either p or d-orbital characters shared partially in the Ho-ligands interactions. Natural charges analysis revealed the presence of significant amount of electron density (0.9225-0.9300 e) transferred from the ligands to Ho (2.0700-2.0775 e). Spherical spin density with ∼4.0 e is predicted over the Ho atom.

Transfection of the Human Heme Oxygenase Gene Into Rabbit Coronary Microvessel Endothelial Cells: Protective Effect Against Heme and Hemoglobin Toxicity

NASA Astrophysics Data System (ADS)

Abraham, N. G.; Lavrovsky, Y.; Schwartzman, M. L.; Stoltz, R. A.; Levere, R. D.; Gerritsen, M. E.

1995-07-01

Heme oxygenase (HO) is a stress protein and has been suggested to participate in defense mechanisms against agents that may induce oxidative injury such as metals, endotoxin, heme/hemoglobin, and various cytokines. Overexpression of HO in cells might therefore protect against oxidative stress produced by certain of these agents, specifically heme and hemoglobin, by catalyzing their degradation to bilirubin, which itself has antioxidant properties. We report here the successful in vitro transfection of rabbit coronary microvessel endothelial cells with a functioning gene encoding the human HO enzyme. A plasmid containing the cytomegalovirus promoter and the human HO cDNA complexed to cationic liposomes (Lipofectin) was used to transfect rabbit endothelial cells. Cells transfected with human HO exhibited an ≈3.0-fold increase in enzyme activity and expressed a severalfold induction of human HO mRNA as compared with endogenous rabbit HO mRNA. Transfected and nontransfected cells expressed factor VIII antigen and exhibited similar acetylated low-density lipoprotein uptake (two important features that characterize endothelial cells) with >85% of cells staining positive for each marker. Moreover, cells transfected with the human HO gene acquired substantial resistance to toxicity produced by exposure to recombinant hemoglobin and heme as compared with nontransfected cells. The protective effect of HO overexpression against heme/hemoglobin toxicity in endothelial cells shown in these studies provides direct evidence that the inductive response of human HO to such injurious stimuli represents an important tissue adaptive mechanism for moderating the severity of cell damage produced by these blood components.

Cerebroprotective functions of HO-2.

PubMed

Parfenova, Helena; Leffler, Charles W

2008-01-01

The constitutive isoform of heme oxygenase, HO-2, is highly expressed in the brain and in cerebral vessels. HO-2 functions in the brain have been evaluated using pharmacological inhibitors of the enzyme and HO-2 gene deletion in in vivo animal models and in cultured cells (neurons, astrocytes, cerebral vascular endothelial cells). Rapid activation of HO-2 via post-translational modifications without upregulation of HO-2 expression or HO-1 induction coincides with the increase in cerebral blood flow aimed at maintaining brain homeostasis and neuronal survival during seizures, hypoxia, and hypotension. Pharmacological inhibition or gene deletion of brain HO-2 exacerbates oxidative stress induced by seizures, glutamate, and inflammatory cytokines, and causes cerebral vascular injury. Carbon monoxide (CO) and bilirubin, the end products of HO-catalyzed heme degradation, have distinct cytoprotective functions. CO, by binding to a heme prosthetic group, regulates the key components of cell signaling, including BK(Ca) channels, guanylyl cyclase, NADPH oxidase, and the mitochondria respiratory chain. Cerebral vasodilator effects of CO are mediated via activation of BK(Ca) channels and guanylyl cyclase. CO, by inhibiting the major components of endogenous oxidant-generating machinery, NADPH oxidase and the cytochrome C oxidase of the mitochondrial respiratory chain, blocks formation of reactive oxygen species. Bilirubin, via redox cycling with biliverdin, is a potent oxidant scavenger that removes preformed oxidants. Overall, HO-2 has dual housekeeping cerebroprotective functions by maintaining autoregulation of cerebral blood flow aimed at improving neuronal survival in a changing environment, and by providing an effective defense mechanism that blocks oxidant formation and prevents cell death caused by oxidative stress.

Development of two measures of client engagement for use in home aged care.

PubMed

Baker, Jess Rose; Harrison, Fleur; Low, Lee-Fay

2016-05-01

The aim of the study was to develop and validate measures of client engagement in aged homecare. The Homecare Measure of Engagement-Staff questionnaire (HoME-S) is a self-complete measure of six dimensions of client engagement: client acceptance, attention, attitude, appropriateness, engagement duration and passivity. The Homecare Measure of Engagement-Client/Family report (HoME-CF) is a researcher-rated interview which obtains client and/or family perspectives regarding frequency and valence of conversational and recreational engagement during care worker visits. Care workers (n = 84) completed the HoME-S and a measure of relationship bond with client. Researchers interviewed clients (n = 164) and/or their family (n = 117) and completed the HoME-CF, and measures of agitation, dysphoria, apathy and cognitive functioning. The HoME-S and HoME-CF demonstrated good test-retest and inter-rater reliability, and showed significant negative correlations with apathy, agitation and non-English-speaking background. Controlling for client and care service characteristics, a stronger care worker-client relationship bond and English-speaking background were independently associated with higher HoME-S scores, and apathy was independently associated with higher HoME-CF scores. In conclusion, the HoME-S and HoME-CF are psychometrically sound engagement measures for use in homecare. Clients who are apathetic or from non-English-speaking backgrounds may be less responsive to traditional care worker engagement strategies. Engagement may be augmented in clients who have stronger relationships with their care workers. © 2015 John Wiley & Sons Ltd.

Butylated Hydroxyanisole Stimulates Heme Oxygenase-1 Gene Expression and Inhibits Neointima Formation in Rat Arteries

PubMed Central

Liu, Xiao-ming; Azam, Mohammed A.; Peyton, Kelly J.; Ensenat, Diana; Keswani, Amit N.; Wang, Hong; Durante, William

2007-01-01

Objective Butylated hydroxyanisole (BHA) is a synthetic phenolic compound that is a potent inducer of phase II genes. Since heme oxygenase-1 (HO-1) is a vasoprotective protein that is upregulated by phase II inducers, the present study examined the effects of BHA on HO-1 gene expression and vascular smooth muscle cell proliferation. Methods The regulation of HO-1 gene expression and vascular cell growth by BHA was studied in cultured rat aortic smooth muscle cells and in balloon injured rat carotid arteries. Results Treatment of cultured smooth muscle cells with BHA stimulated the expression of HO-1 protein, mRNA and promoter activity in a time- and concentration-dependent manner. BHA-mediated HO-1 expression was dependent on the activation of NF-E2-related factor-2 by p38 mitogen-activated protein kinase. BHA also inhibited cell cycle progression and DNA synthesis in a HO-1-dependent manner. In addition, the local perivascular delivery of BHA immediately after arterial injury of rat carotid arteries induced HO-1 protein expression and markedly attenuated neointima formation. Conclusions These studies demonstrate that BHA stimulates HO-1 gene expression in vascular smooth muscle cells, and that the induction of HO-1 contributes to the antiproliferative actions of this phenolic antioxidant. BHA represents a potentially novel therapeutic agent in treating or preventing vasculoproliferative disease. PMID:17320844

Sensitizing effect of Ho3+ on the Er3+: 2.7 μm-emission in fluoride glass

NASA Astrophysics Data System (ADS)

Huang, Feifei; Li, Xia; Liu, Xueqiang; Zhang, Junjie; Hu, Lili; Chen, Danping

2014-03-01

The fluorescence properties of 2.7 μm emission and energy transfer mechanism of Ho3+/Er3+ co-doped fluoride glass (ZBYA) have been investigated in the present paper. Ho3+ strengthens the Er3+: 2.7 μm emission in the ZBYA glasses due to the energy transfer from Er3+ to Ho3+, while the 1.5 μm emission decreases dramatically. The optimized concentration ratio of Er3+ to Ho3+ is found to be 1:1 in our glass system. The absorption and emission spectra are tested and the sample possesses large emission cross section (16.5 × 10-21 cm2) around 2.7 μm along with larger radiative transition probability (25.11 S-1) on the basis of Judd-Ofelt and Fuchtbauer-Ladenburg theories. Additionally, the energy transfer microparameters are calculated using Förster-Dexter theory and the result shows the energy transfer coefficient of Er3+:4I13/2 → Ho3+:5I7 is 24 times larger than that of Er3+:4I11/2 → Ho3+:5I6. Our results show that Er3+: 2.7 μm emission can be sensitized by Ho3+ efficiently, and this Er3+/Ho3+-codoped fluoride glasses might have potential application in mid-infrared lasers.

Modulation of cGMP by human HO-1 retrovirus gene transfer in pulmonary microvessel endothelial cells.

PubMed

Abraham, Nader G; Quan, Shuo; Mieyal, Paul A; Yang, Liming; Burke-Wolin, Theresa; Mingone, Christopher J; Goodman, Alvin I; Nasjletti, Alberto; Wolin, Michael S

2002-11-01

Carbon monoxide (CO) stimulates guanylate cyclase (GC) and increases guanosine 3',5'-cyclic monophosphate (cGMP) levels. We transfected rat-lung pulmonary endothelial cells with a retrovirus-mediated human heme oxygenase (hHO)-1 gene. Pulmonary cells that expressed hHO-1 exhibited a fourfold increase in HO activity associated with decreases in the steady-state levels of heme and cGMP without changes in soluble GC (sGC) and endothelial nitric oxide synthase (NOS) proteins or basal nitrite production. Heme elicited significant increases in CO production and intracellular cGMP levels in both pulmonary endothelial and pulmonary hHO-1-expressing cells. N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, significantly decreased cGMP levels in heme-treated pulmonary endothelial cells but not heme-treated hHO-1-expressing cells. In the presence of exogenous heme, CO and cGMP levels in hHO-1-expressing cells exceeded the corresponding levels in pulmonary endothelial cells. Acute exposure of endothelial cells to SnCl2, which is an inducer of HO-1, increased cGMP levels, whereas chronic exposure decreased heme and cGMP levels. These results indicate that prolonged overexpression of HO-1 ultimately decreases sGC activity by limiting the availability of cellular heme. Heme activates sGC and enhances cGMP levels via a mechanism that is largely insensitive to NOS inhibition.

Effects of combined mesenchymal stem cells and heme oxygenase-1 therapy on cardiac performance.

PubMed

Zeng, Bin; Chen, Honglei; Zhu, Chengang; Ren, Xiaofeng; Lin, Guosheng; Cao, Feng

2008-10-01

Bone marrow mesenchymal stem cells (MSCs) have the potential to repair the infarcted myocardium and improve cardiac function. However, this approach is limited by its poor viability after transplantation, and controversy still exists over the mechanism by which MSCs contribute to the tissue repair. The human heme oxygenase-1 (hHO-1) was transfected into cultured MSCs using an adenoviral vector. 1 x 10(6) Ad-hHO-1-transfected MSCs (HO-1-MSCs) or Ad-Null-transfected MSCs (Null-MSCs) or PBS only (PBS group) were injected intramyocardially into rat hearts 1h after myocardial infarction. HO-1-MSCs survived in the infarcted myocardium, and expressed hHO-1 mRNA. The expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) was significantly enhanced in HO-1-MSCs-treated hearts. At the same time, there were significant reduction of TNF-alpha, IL-1-beta and IL-6 mRNA, and marked increase of IL-10 mRNA in HO-1-MSCs-treated hearts. Moreover, a further downregulation of proapoptotic protein, Bax, and a marked increase in microvessel density were observed in HO-1-MSCs-treated hearts. The infarct size and cardiac performance were also significantly improved in HO-1-MSCs-treated hearts. The combined approach improves MSCs survival and is superior to MSCs injection alone.

Interventions for the treatment of craniopharyngioma-related hypothalamic obesity: a systematic review.

PubMed

Ni, Weimin; Shi, Xiang'en

2018-06-23

Craniopharyngiomas (CPs) and their treatment are associated with hypothalamic damage that causes hypothalamic obesity (HO) in 30-70% of cases. Thus, there is ongoing research regarding tangible solutions for HO, as these patients have unrelenting resistance to basic weight-loss interventions. This review aims to summarize the interventions that are currently used to treat CP-related HO (CP-HO), including pharmacotherapy and bariatric surgery. The Cochrane Library, EMBASE, and PubMed databases were searched up to June 2017 for relevant reports. Two reviewers conducted independent evaluations of the identified studies. Eighteen publications were included in the systematic review, with three reports describing pharmacotherapy in randomized controlled trials and 15 reports describing bariatric surgery. Although several studies described effective interventions for treating CP-HO, the evidence base was limited by its low quality and our inability to perform a meta-analysis, which was related to a lack of adequate or integrated data. Octreotide appears to be a preferred treatment for CP-HO patients, based on currently limited data. Gastric bypass surgery may also be suitable for select CP-HO patients, based on a review of various procedures in this setting. Microsurgical preservation of the hypothalamic structures is mandatory to decrease CP-HO-related morbidity and mortality. Further studies with adequate analytical power and sufficient follow-up are needed to identify effective strategies for CP-HO treatment. Copyright © 2018 Elsevier Inc. All rights reserved.

An open-source framework for stress-testing non-invasive foetal ECG extraction algorithms.

PubMed

Andreotti, Fernando; Behar, Joachim; Zaunseder, Sebastian; Oster, Julien; Clifford, Gari D

2016-05-01

Over the past decades, many studies have been published on the extraction of non-invasive foetal electrocardiogram (NI-FECG) from abdominal recordings. Most of these contributions claim to obtain excellent results in detecting foetal QRS (FQRS) complexes in terms of location. A small subset of authors have investigated the extraction of morphological features from the NI-FECG. However, due to the shortage of available public databases, the large variety of performance measures employed and the lack of open-source reference algorithms, most contributions cannot be meaningfully assessed. This article attempts to address these issues by presenting a standardised methodology for stress testing NI-FECG algorithms, including absolute data, as well as extraction and evaluation routines. To that end, a large database of realistic artificial signals was created, totaling 145.8 h of multichannel data and over one million FQRS complexes. An important characteristic of this dataset is the inclusion of several non-stationary events (e.g. foetal movements, uterine contractions and heart rate fluctuations) that are critical for evaluating extraction routines. To demonstrate our testing methodology, three classes of NI-FECG extraction algorithms were evaluated: blind source separation (BSS), template subtraction (TS) and adaptive methods (AM). Experiments were conducted to benchmark the performance of eight NI-FECG extraction algorithms on the artificial database focusing on: FQRS detection and morphological analysis (foetal QT and T/QRS ratio). The overall median FQRS detection accuracies (i.e. considering all non-stationary events) for the best performing methods in each group were 99.9% for BSS, 97.9% for AM and 96.0% for TS. Both FQRS detections and morphological parameters were shown to heavily depend on the extraction techniques and signal-to-noise ratio. Particularly, it is shown that their evaluation in the source domain, obtained after using a BSS technique, should be avoided. Data, extraction algorithms and evaluation routines were released as part of the fecgsyn toolbox on Physionet under an GNU GPL open-source license. This contribution provides a standard framework for benchmarking and regulatory testing of NI-FECG extraction algorithms.

Evidence-based outcomes of holmium laser enucleation of the prostate.

PubMed

Large, Tim; Krambeck, Amy E

2018-05-01

Holmium laser enucleation of the prostate (HoLEP) has been a mainstay therapy for the treatment of lower urinary tract symptoms (LUTS) secondary to benign prostate hyperplasia (BPH) for nearly 20 years. We briefly review current and sentinel publications that provide outcomes data after HoLEP. Current literature continues to support HoLEP as a versatile and durable surgical option for men with LUTS secondary to BPH. Despite evidence supporting durable symptom relief beyond 10 years even in large prostate glands, HoLEP is still not widely available to all patients. Concerns surrounding the learning curve of the procedure, high rates of retrograde ejaculation, and transient urinary incontinence seem to persist and limit the adoption of HoLEP by established urologists and residency training programs. Recent publications continue to show excellent short-term and long-term outcomes after HoLEP, in the categories of voiding function and patient satisfaction. Continued attempts to demonstrate equivalent outcomes of alternate-BPH surgical techniques are being met with renewed efforts by those performing HoLEP to demonstrate equivalent outcomes and patient safety during the learning phase of HoLEP for both mentored and self-directed surgical training.

Beneficial effects of the heme oxygenase-1/carbon monoxide system in patients with severe sepsis/septic shock.

PubMed

Takaki, Shoji; Takeyama, Naoshi; Kajita, Yuka; Yabuki, Teru; Noguchi, Hiroki; Miki, Yasuo; Inoue, Yasusuke; Nakagawa, Takashi; Noguchi, Hiroshi

2010-01-01

We evaluated the relations among the arterial carbon monoxide (CO) concentration, heme oxygenase (HO)-1 expression by monocytes, oxidative stress, plasma levels of cytokines and bilirubin, and the outcome of patients with severe sepsis or septic shock. Thirty-six patients who fulfilled the criteria for severe sepsis or septic shock and 21 other patients without sepsis during their stay in the intensive care unit were studied. HO-1 protein expression by monocytes, arterial CO, oxidative stress, bilirubin, and cytokines were measured. Arterial blood CO, cytokine, and bilirubin levels, and monocyte HO-1 protein expression were higher in patients with severe sepsis/septic shock than in non-septic patients. Increased HO-1 expression was related to the arterial CO concentration and oxidative stress. There was a positive correlation between survival and increased HO-1 protein expression or a higher CO level. Arterial CO and monocyte HO-1 protein expression were increased in critically ill patients, particularly those with severe sepsis or septic shock, suggesting that oxidative stress is closely related to HO-1 expression. The HO-1/CO system may play an important role in sepsis.

Direct Mouse Trauma/Burn Model of Heterotopic Ossification

PubMed Central

Peterson, Jonathan R.; Agarwal, Shailesh; Brownley, R. Cameron; Loder, Shawn J.; Ranganathan, Kavitha; Cederna, Paul S.; Mishina, Yuji; Wang, Stewart C.; Levi, Benjamin

2015-01-01

Heterotopic ossification (HO) is the formation of bone outside of the skeleton which forms following major trauma, burn injuries, and orthopaedic surgical procedures. The majority of animal models used to study HO rely on the application of exogenous substances, such as bone morphogenetic protein (BMP), exogenous cell constructs, or genetic mutations in BMP signaling. While these models are useful they do not accurately reproduce the inflammatory states that cause the majority of cases of HO. Here we describe a burn/tenotomy model in mice that reliably produces focused HO. This protocol involves creating a 30% total body surface area partial thickness contact burn on the dorsal skin as well as division of the Achilles tendon at its midpoint. Relying solely on traumatic injury to induce HO at a predictable location allows for time-course study of endochondral heterotopic bone formation from intrinsic physiologic processes and environment only. This method could prove instrumental in understanding the inflammatory and osteogenic pathways involved in trauma-induced HO. Furthermore, because HO develops in a predictable location and time-course in this model, it allows for research to improve early imaging strategies and treatment modalities to prevent HO formation. PMID:26274052

Adiponectin-Mediated Heme Oxygenase-1 Induction Protects Against Iron-Induced Liver Injury via a PPARα-Dependent Mechanism

PubMed Central

Lin, Heng; Yu, Chun-Hsien; Jen, Chih-Yu; Cheng, Ching-Feng; Chou, Ying; Chang, Chih-Cheng; Juan, Shu-Hui

2010-01-01

Protective effects of adiponectin (APN; an adipocytokine) were shown against various oxidative challenges; however, its therapeutic implications and the mechanisms underlying hepatic iron overload remain unclear. Herein, we show that the deleterious effects of iron dextran on liver function and iron deposition were significantly reversed by adiponectin gene therapy, which was accompanied by AMP-activated protein kinase (AMPK) phosphorylation and heme oxygenase (HO)-1 induction. Furthermore, AMPK-mediated peroxisome proliferator-activated receptor-α (PPARα) activation by APN was ascribable to HO-1 induction. Additionally, we revealed direct transcriptional regulation of HO-1 by the binding of PPARα to a PPAR-responsive element (PPRE) by various experimental assessments. Interestingly, overexpression of HO-1 in hepatocytes mimicked the protective effect of APN in attenuating iron-mediated injury, whereas it was abolished by SnPP and small interfering HO-1. Furthermore, bilirubin, the end-product of the HO-1 reaction, but not CO, protected hepatocytes from iron dextran-mediated caspase activation. Herein, we demonstrate a novel functional PPRE in the promoter regions of HO-1, and APN-mediated HO-1 induction elicited an antiapoptotic effect and a decrease in iron deposition in hepatocytes subjected to iron challenge. PMID:20709802

Carbon monoxide derived from heme oxygenase-2 mediates reduction of methylmercury toxicity in SH-SY5Y cells

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

Toyama, Takashi; Research Fellow of the Japan Society for the Promotion of Science; Shinkai, Yasuhiro

2010-11-15

We examined the contribution of carbon monoxide (CO), an enzymatic product of heme oxygenase (HO), to methylmercury (MeHg) cytotoxicity in SH-SY5Y cells, because this gas molecule is reported to activate Nrf2, which plays a protective role against MeHg-mediated cell damage. Exposure of SH-SY5Y cells to CO gas resulted in protection against MeHg cytotoxicity, with activation of Nrf2. Interestingly, pretreatment with tin-protoporphyrin IX, a specific inhibitor of HO, caused a reduction in basal Nrf2 activity and thus enhanced sensitivity to MeHg. No induction of isoform 1 of HO (HO-1) was seen during MeHg exposure, but constitutive expression of isoform 2 (HO-2)more » occurred, suggesting that CO produced by HO-2 is the main participant in the protection against MeHg toxicity. Studies of small interfering RNA-mediated knockdown of HO-2 in the cells supported this possibility. Our results suggest that CO gas and its producing enzyme HO-2 are key molecules in cellular protection against MeHg, presumably through basal activation of Nrf2.« less

Cysteine-independent activation/inhibition of heme oxygenase-2

PubMed Central

Vukomanovic, Dragic; Rahman, Mona N.; Maines, Mahin D.; Ozolinš, Terence RS; Szarek, Walter A.; Jia, Zongchao; Nakatsu, Kanji

2016-01-01

Reactive thiols of cysteine (cys) residues in proteins play a key role in transforming chemical reactivity into a biological response. The heme oxygenase-2 (HO-2) isozyme contains two cys residues that have been implicated in binding of heme and also the regulation of its activity. In this paper, we address the question of a role for cys residues for the HO-2 inhibitors or activators designed in our laboratory. We tested the activity of full length recombinant human heme oxygenase-2 (FL-hHO-2) and its analog in which cys265 and cys282 were both replaced by alanine to determine the effect on activation by menadione (MD) and inhibition by QC-2350. Similar inhibition by QC-2350 and almost identical activation by MD was observed for both recombinant FL-hHO-2s. Our findings are interpreted to mean that thiols of FL-hHO-2s are not involved in HO-2 activation or inhibition by the compounds that have been designed and identified by us. Activation or inhibition of HO-2 by our compounds should be attributed to a mechanism other than altering binding affinity of HO-2 for heme through cys265 and cys282. PMID:27826418

Cysteine-independent activation/inhibition of heme oxygenase-2.

PubMed

Vukomanovic, Dragic; Rahman, Mona N; Maines, Mahin D; Ozolinš, Terence Rs; Szarek, Walter A; Jia, Zongchao; Nakatsu, Kanji

2016-03-01

Reactive thiols of cysteine (cys) residues in proteins play a key role in transforming chemical reactivity into a biological response. The heme oxygenase-2 (HO-2) isozyme contains two cys residues that have been implicated in binding of heme and also the regulation of its activity. In this paper, we address the question of a role for cys residues for the HO-2 inhibitors or activators designed in our laboratory. We tested the activity of full length recombinant human heme oxygenase-2 (FL-hHO-2) and its analog in which cys265 and cys282 were both replaced by alanine to determine the effect on activation by menadione (MD) and inhibition by QC-2350. Similar inhibition by QC-2350 and almost identical activation by MD was observed for both recombinant FL-hHO-2s. Our findings are interpreted to mean that thiols of FL-hHO-2s are not involved in HO-2 activation or inhibition by the compounds that have been designed and identified by us. Activation or inhibition of HO-2 by our compounds should be attributed to a mechanism other than altering binding affinity of HO-2 for heme through cys265 and cys282.

On the study of rotational effects in mass asymmetric colliding nuclei at intermediate energies

NASA Astrophysics Data System (ADS)

Kaur, Kamaldeep; Kumar, Suneel

2018-05-01

The rotational dynamics has been studied for different mass asymmetric systems 49122In + 50126Sn, 48114Cs + 54134In, 40100Mo + 64148Gd, 3686Kr + 67162Ho, 3171Ga + 71177Lu, 2860Ni + 76188Os and 2450Cr + 78198 Pt for incident energies between 40 MeV/nucleon and 400 MeV/nucleon for impact parameter range 0.25 < b ˆ < 0.45 using isospin-dependent quantum molecular dynamics (IQMD) model. Our calculations reveal that the time evolutions of rotational observables for participant and spectator nuclear matter are different in mass asymmetric heavy ion reactions. Theoretical data of BUU model's azimuthal distributions for free protons have been compared successfully with IQMD model calculations. The rotational flow of free protons with increasing incident energies and elliptic flow (calculated from the fits of azimuthal distributions of free protons) dependence with energy has also been investigated.

Reduced ternary molybdenum and tungsten sulfides and hydroprocessing catalysis therewith

DOEpatents

Hilsenbeck, S.J.; McCarley, R.E.; Schrader, G.L.; Xie, X.B.

1999-02-16

New amorphous molybdenum/tungsten sulfides with the general formula M{sup n+}{sub 2x/n}(L{sub 6}S{sub 8})S{sub x}, where L is molybdenum or tungsten and M is a ternary metal, has been developed. Characterization of these amorphous materials by chemical and spectroscopic methods (IR, Raman, PES) shows that the (M{sub 6}S{sub 8}){sup 0} cluster units are present. Vacuum thermolysis of the amorphous Na{sub 2x}(Mo{sub 6}S{sub 8})S{sub x}{hor_ellipsis}yMeOH first produces poorly crystalline NaMo{sub 6}S{sub 8} by disproportionation at 800 C and well-crystallized NaMo{sub 6}S{sub 8} at {>=} 900 C. Ion-exchange of the sodium material in methanol with soluble M{sup 2+} and M{sup 3+} salts (M=Sn, Co, Ni, Pb, La, Ho) produces the M{sup n+}{sub 2x/n}(Mo{sub 6}S{sub 8})S{sub x}{hor_ellipsis}yMeOH compounds. Additionally, the new reduced ternary molybdenum sulfides with the general formula M{sup n+}{sub 2x/n}Mo{sub 6}S{sub 8+x}(MeOH){sub y}[MMOS] (M=Sn, Co, Ni) is an effective hydrodesulfurization (HDS) catalyst both as-prepared and after a variety of pretreatment conditions. Under specified pretreatment conditions with flowing hydrogen gas, the SnMoS type catalyst can be stabilized, and while still amorphous, can be considered as ``Chevrel phase-like`` in that both contain Mo{sub 6}S{sub 8} cluster units. Furthermore, the small cation NiMoS and CoMoS type pretreated catalyst is shown to be very active HDS catalysts with rates that exceeded the model unpromoted and cobalt-promoted MoS{sub 2} catalysts. 9 figs.

Reduced ternary molybdenum and tungsten sulfides and hydroprocessing catalysis therewith

DOEpatents

Hilsenbeck, Shane J.; McCarley, Robert E.; Schrader, Glenn L.; Xie, Xiaobing

1999-02-16

New amorphous molybdenum/tungsten sulfides with the general formula M.sup.n+.sub.2x/n (L.sub.6 S.sub.8)S.sub.x, where L is molybdenum or tungsten and M is a ternary metal, has been developed. Characterization of these amorphous materials by chemical and spectroscopic methods (IR, Raman, PES) shows that the (M.sub.6 S.sub.8).sup.0 cluster units are present. Vacuum thermolysis of the amorphous Na.sub.2x (Mo.sub.6 S.sub.8)S.sub.x .multidot.yMeOH first produces poorly crystalline NaMo.sub.6 S.sub.8 by disproportionation at 800.degree. C. and well-crystallized NaMo.sub.6 S.sub.8 at .gtoreq. 900.degree. C. Ion-exchange of the sodium material in methanol with soluble M.sup.2+ and M.sup.3+ salts (M=Sn, Co, Ni, Pb, La, Ho) produces the M.sup.n+.sub.2x/n (Mo.sub.6 S.sub.8)S.sub.x .multidot.yMeOH compounds. Additionally, the new reduced ternary molybdenum sulfides with the general formula M.sup.n+.sub.2x/n Mo.sub.6 S.sub.8+x (MeOH).sub.y ›MMOS! (M=Sn, Co, Ni) is an effective hydrodesulfurization (HDS) catalyst both as-prepared and after a variety of pretreatment conditions. Under specified pretreatment conditions with flowing hydrogen gas, the SnMoS type catalyst can be stabilized, and while still amorphous, can be considered as "Chevrel phase-like" in that both contain Mo.sub.6 S.sub.8 cluster units. Furthermore, the small cation NiMoS and CoMoS type pretreated catalyst showed to be very active HDS catalysts with rates that exceeded the model unpromoted and cobalt-promoted MoS.sub.2 catalysts.

The effect of curcumin on insulin release in rat-isolated pancreatic islets.

PubMed

Abdel Aziz, Mohamed T; El-Asmar, Mohamed F; El Nadi, Essam G; Wassef, Mohamed A; Ahmed, Hanan H; Rashed, Laila A; Obaia, Eman M; Sabry, Dina; Hassouna, Amira A; Abdel Aziz, Ahmed T

2010-08-01

Curcumin exerts a hypoglycemic action and induces heme-oxygenase-1 (HO-1). We evaluated the effect of curcumin on isolated islets of Langerhans and studied whether its action on insulin secretion is mediated by inducible HO-1. Islets were isolated from rats and divided into control islets, islets incubated in different curcumin concentrations, islets incubated in hemin, islets incubated in curcumin and HO inhibitor, stannous mesoporphyrin (SnMP), islets incubated in hemin and SnMP, islets incubated in SnMP only, and islets incubated in 16.7 mmol/L glucose. Heme-oxygenase activity, HO-1 expression, and insulin estimation was assessed. Insulin secretion, HO-1 gene expression and HO activity were significantly increased in islets incubated in curcumin, hemin, and glucose compared with controls. This increase in insulin secretion was significantly decreased by incubation of islets in SnMP. The action of curcumin on insulin secretion from the isolated islets may be, in part, mediated through increased HO-1 gene expression.

Crystal Growth and Scintillation Properties of Ho-Doped Lu3Al5O12 Single Crystals

NASA Astrophysics Data System (ADS)

Sugiyama, Makoto; Yanagida, Takayuki; Fujimoto, Yutaka; Totsuka, Daisuke; Yokota, Yuui; Kurosawa, Shunsuke; Futami, Yoshisuke; Yoshikawa, Akira

2012-10-01

The crystals of 0.1, 0.5, 1, and 3% Ho doped Lu3Al5O12 (Ho:LuAG) grown by the micro-pulling-down method were examined for their scintillation properties. At wavelengths longer than 300 nm, Ho:LuAG crystals demonstrated around 60% transparency with many absorption peaks attributed to Ho3+ 4f10-4 f10 transitions. When excited by 241Am α-ray to obtain radio luminescence spectra, broad host emission and four sharp Ho3+ 4f10-4 f10 emission peaks were detected in the visible region. Light yields and decay time profiles of the samples irradiated by 137Cs γ-ray were measured using photomultiplier tubes R7600 (Hamamatsu). Ho 0.5%:LuAG showed the highest light yield of 3100 ±310 photons/MeV among the present samples. The decay time profiles were well reproduced by two components exponential approximation consisting of 0.5-1 μs and 3-6 μs.

Predicting lanthanide cluster properties: a comparison with the observed optical spectra of HO 2

NASA Astrophysics Data System (ADS)

Nemukhin, A. V.; Ermilov, A. Yu.; Petrukhina, M. A.; Klotzbücher, W. E.; Smets, J.

1997-10-01

Ab initio pseudopotential calculations for HO and HO 2 have been carried out in order to support an assignment of the bands observed in UV-visible spectra of matrix isolated holmium species. SCF, MCSCF and configuration interaction (CI) procedures have been used with quasirelativistic pseudopotentials to compute the ground and excited state energies of HO and HO 2, together with the dipole transition moments. For HO 2, using a Q = 11 pseudopotential (describing the holmium atom in the 4f 106s 25d 1 electronic state), two transitions from the ground state σg2σu2πu2 to the states with principal excitations σu → πg and π u → σ g∗ are predicted at 499 and 524 nm. These two lines, with predicted close intensities, correlate nicely with the observed features at 498/504 and 558/563nm in the spectrum of matrix-isolated HO 2.

TRACE-P OH and HO2 Measurements with the Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) on the DC-8

NASA Technical Reports Server (NTRS)

Brune, William H.; Martinez-Harder, Monica; Harder, Hartwig

2004-01-01

The Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) measures OH and HO2 from the NASA DC-8. This instrument detects OH by laser induced fluorescence (LIF) in detection chambers at low pressure and detects HO2 by chemical conversion with NO followed by LIF detection. The demonstrated detection limit (S/N=2, 5 min.) for OH is about 0.005 pptv (1x10(exp 6)/cu cm at 2 km altitude) and for HO2 is 0.05 pptv (1x10(exp 6)/cu cm at 2 km altitude). We will use ATHOS to measure OH, HO2, and HO2/OH during TRACE- P, analyze these results by comparing them against fundamental relationships and computer models, and publish the analyses. TRACE-P HO(x), measurements will help develop a clearer picture of the atmospheric oxidation and 0 3 production that occur as Asian pollution spreads across the Pacific Ocean.

VizieR Online Data Catalog: VLBI Ecliptic Plane Survey: VEPS-1 (Shu+, 2017)

NASA Astrophysics Data System (ADS)

Shu, F.; Petrov, L.; Jiang, W.; Xia, B.; Jiang, T.; Cui, Y.; Takefuji, K.; McCallum, J.; Lovell, J.; Yi, S.-O.; Hao, L.; Yang, W.; Zhang, H.; Chen, Z.; Li, J.

2017-08-01

We began observations in the search mode in 2015 February. The participating stations included the three core stations of the Chinese VLBI Network (CVN): seshan25, kunming, and urumqi. Depending on the participating stations, the longest baseline length in each session can be varied from 3200km to 9800km. Our observations were performed at a 2048Mbps data rate, with 16 Intermediate Frequency (IF) channels and 2-bit sampling. The first eight IFs of 32MHz bandwidth were distributed in the range of [8.188, 8.444]GHz, and the remaining eight IFs of 32MHz bandwidth were in the range of [8.700, 8.956]GHz. Table 1: Summary of the VLBI Ecliptic Plane Survey (VEPS) observations in search mode: --------------------------------------------------- Date Dur. Code Stations Number of (Y/M/D) (h) Targets --------------------------------------------------- 2015 Feb 13 24 VEPS01 ShKmUr 293 2015 Feb 14 24 VEPS02 ShKmUr 338 2015 Apr 23 24 VEPS03 UrKv 300 2015 Apr 24 24 VEPS04 ShKmUrKv 400 2015 Aug 10 25 VEPS05 ShKmKvHo 252 2015 Aug 19 25 VEPS06 ShKmKvHo 277 2016 Mar 02 24 VEPS07 ShKmUrKb 333 2016 Mar 11 24 VEPS08 ShKmUrKb 477 2016 May 13 24 VEPS09 ShUrHo 291 2016 May 14 22 VEPS10 ShUrKv 322 2016 Jul 06 24 VEPS11 ShUrKb 307 2016 Sep 02 23 VEPS12 ShUr 424 2016 Sep 03 23 VEPS13 ShKmUr 344 --------------------------------------------------- Sh=Seshan25; Km=Kunming; Ur=Urumqi; Kv=Sejong; Kb=Kashim34; Ho=Hobart26. --------------------------------------------------- We ran two absolute astrometry dual-band VLBA programs that targeted ecliptic plane compact radio sources: the dedicated survey of weak ecliptic plane calibrators with the VLBA BS250 program in 2016 March-May, and the VLBA Calibrator Survey 9 (VCS-9) in 2015 August-2016 September. The International VLBI Service for Geodesy and Astrometry (IVS) runs a number of VLBI observing programs. We made an attempt to improve the coordinates of some VEPS sources detected in the search mode and provide additional measurements of telescope position with the same experiments in two such 24hr sessions, AOV010 in July and AUA012 in 2016 August. (2 data files).

Diffusion in thoriated and nonthoriated nickel and nickel-chromium alloys at 1260 C

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.

1972-01-01

Various solid-solid diffusion couples were assembled from thoriated and nonthoriated nickel-base alloys, welded, and diffusion annealed at 1260 C. Concentration profiles indicated that a thoria dispersion does not affect diffusion in Cr(alloy):Ni and Ni-4.8Al:Ni types of couples unless a fine grain structure is retained by the thoria particles. Metallography revealed the presence of thoria-free bands in the thoriated-Ni side of the diffusion zone. The bands contained grain boundaries and, in some cases, non-Kirkendall porosity. A mechanism based on the operation of vacancy sources is proposed to explain the thoria-free bands. In addition, a particular DS-NiCr:Ni couple had negligible Kirkendall porosity. This behavior was related to the grain structure of the particular lot of DS-NiCr.

Measurements of HO2 chemical kinetics with a new detection method

NASA Technical Reports Server (NTRS)

Lee, L. C.; Suto, M.

1986-01-01

Research for the period from December 1, 1985 to May 31, 1986 is discussed, i.e., the reaction rate constant of HO2+O3 has been measured with a discharge-flow-tube apparatus. The HO2 radical was detected by the OH(A-X) photofragment emission produced from photodissociative excitation of HO2 at 147 nm. In the meantime, the optical emissions produced by the vacuum ultraviolet excitation of chemical species in the flow tube were investigated and used to examine the possibility for their interference with the HO2 detection. The research results are summarized below.

Mining the Mind Research Network: A Novel Framework for Exploring Large Scale, Heterogeneous Translational Neuroscience Research Data Sources

PubMed Central

Bockholt, Henry J.; Scully, Mark; Courtney, William; Rachakonda, Srinivas; Scott, Adam; Caprihan, Arvind; Fries, Jill; Kalyanam, Ravi; Segall, Judith M.; de la Garza, Raul; Lane, Susan; Calhoun, Vince D.

2009-01-01

A neuroinformatics (NI) system is critical to brain imaging research in order to shorten the time between study conception and results. Such a NI system is required to scale well when large numbers of subjects are studied. Further, when multiple sites participate in research projects organizational issues become increasingly difficult. Optimized NI applications mitigate these problems. Additionally, NI software enables coordination across multiple studies, leveraging advantages potentially leading to exponential research discoveries. The web-based, Mind Research Network (MRN), database system has been designed and improved through our experience with 200 research studies and 250 researchers from seven different institutions. The MRN tools permit the collection, management, reporting and efficient use of large scale, heterogeneous data sources, e.g., multiple institutions, multiple principal investigators, multiple research programs and studies, and multimodal acquisitions. We have collected and analyzed data sets on thousands of research participants and have set up a framework to automatically analyze the data, thereby making efficient, practical data mining of this vast resource possible. This paper presents a comprehensive framework for capturing and analyzing heterogeneous neuroscience research data sources that has been fully optimized for end-users to perform novel data mining. PMID:20461147

Health risks associated with heavy metals in the drinking water of Swat, northern Pakistan.

PubMed

Lu, Yonglong; Khan, Hizbullah; Zakir, Shahida; Ihsanullah; Khan, Sardar; Khan, Akbar Ali; Wei, Luo; Wang, Tieyu

2013-10-01

The concentrations of heavy metals such as Cd, Cr, Cu, Mn, Ni, Pb and Zn were investigated in drinking water sources (surface and groundwater) collected from Swat valley, Khyber Pakhtunkhwa, Pakistan. The potential health risks of heavy metals to the local population and their possible source apportionment were also studied. Heavy metal concentrations were analysed using atomic absorption spectrometer and compared with permissible limits set by Pakistan Environmental Protection Agency and World Health Organization. The concentrations of Cd, Cr, Ni and Pb were higher than their respective permissible limits, while Cu, Mn and Zn concentrations were observed within their respective limits. Health risk indicators such as chronic daily intake (CDI) and health risk index (HRI) were calculated for adults and children separately. CDIs and HRIs of heavy metals were found in the order of Cr > Mn > Ni > Zn > Cd > Cu > Pb and Cd > Ni > Mn > Cr > Cu > Pb > Zn, respectively. HRIs of selected heavy metals in the drinking water were less than 1, indicating no health risk to the local people. Multivariate and univariate statistical analyses showed that geologic and anthropogenic activities were the possible sources of water contamination with heavy metals in the study area.

pH modulation of currents that contribute to the medium and slow afterhyperpolarizations in rat CA1 pyramidal neurones

PubMed Central

Kelly, Tony; Church, John

2004-01-01

We examined the effects of changes in pHo and pHi on currents contributing to the medium and slow afterhyperpolarizations (mIAHP and sIAHP, respectively) in rat CA1 neurones. Reducing pHo from 7.4 to 6.7 inhibited mIAHP and sIAHP whereas increasing pHo to 7.7 augmented mIAHP and, to a greater extent, sIAHP. The ability of changes in pHo to modulate mIAHP reflected changes in the Ca2+-activated K+ current, IAHP, and a Co2+- and XE991-resistant component of mIAHP, but not the muscarine-sensitive current, IM. In the presence of 1 μm TTX and 5 mm TEA, low pHo-evoked reductions in sIAHP were associated with reductions in Ca2+-dependent depolarizing potentials; because neither effect was attenuated when internal H+ buffering power was raised by including 100 mm tricine in the patch pipette, the actions of reductions in pHo to inhibit sIAHP and, possibly, IAHP in large part appear to reflect a low pHo-dependent decrease in Ca2+ influx. In contrast, the effects of high pHo to augment mIAHP and sIAHP were associated with relatively small increases in Ca2+ potentials but were significantly attenuated by 100 mm internal tricine, indicating that a rise in pHi consequent upon the rise in pHo was largely responsible. The possibility that changes in pHi could act to modulate mIAHP and sIAHP, independently of changes in Ca2+ influx, was also suggested by experiments in which pHi was lowered at a constant pHo by the external application of propionate or by the withdrawal of HCO3− from the perfusing medium. Lowering pHi at a constant pHo had little effect on Ca2+ potentials but inhibited mIAHP and, to a greater extent, sIAHP, effects that were attenuated by 100 mm internal tricine. Together, the results indicate that changes in pHo and pHi modulate mIAHP and sIAHP in rat CA1 neurones and suggest that, depending on the direction of the pHo change, the sensitivities of the underlying currents to changes in Ca2+ influx and/or pHi may contribute to the effects of changes in pHo to modulate mIAHP and sIAHP. PMID:14608014

(⁹⁹m)Tc-MAA overestimates the absorbed dose to the lungs in radioembolization: a quantitative evaluation in patients treated with ¹⁶⁶Ho-microspheres.

PubMed

Elschot, Mattijs; Nijsen, Johannes F W; Lam, Marnix G E H; Smits, Maarten L J; Prince, Jip F; Viergever, Max A; van den Bosch, Maurice A A J; Zonnenberg, Bernard A; de Jong, Hugo W A M

2014-10-01

Radiation pneumonitis is a rare but serious complication of radioembolic therapy of liver tumours. Estimation of the mean absorbed dose to the lungs based on pretreatment diagnostic (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) imaging should prevent this, with administered activities adjusted accordingly. The accuracy of (99m)Tc-MAA-based lung absorbed dose estimates was evaluated and compared to absorbed dose estimates based on pretreatment diagnostic (166)Ho-microsphere imaging and to the actual lung absorbed doses after (166)Ho radioembolization. This prospective clinical study included 14 patients with chemorefractory, unresectable liver metastases treated with (166)Ho radioembolization. (99m)Tc-MAA-based and (166)Ho-microsphere-based estimation of lung absorbed doses was performed on pretreatment diagnostic planar scintigraphic and SPECT/CT images. The clinical analysis was preceded by an anthropomorphic torso phantom study with simulated lung shunt fractions of 0 to 30 % to determine the accuracy of the image-based lung absorbed dose estimates after (166)Ho radioembolization. In the phantom study, (166)Ho SPECT/CT-based lung absorbed dose estimates were more accurate (absolute error range 0.1 to -4.4 Gy) than (166)Ho planar scintigraphy-based lung absorbed dose estimates (absolute error range 9.5 to 12.1 Gy). Clinically, the actual median lung absorbed dose was 0.02 Gy (range 0.0 to 0.7 Gy) based on posttreatment (166)Ho-microsphere SPECT/CT imaging. Lung absorbed doses estimated on the basis of pretreatment diagnostic (166)Ho-microsphere SPECT/CT imaging (median 0.02 Gy, range 0.0 to 0.4 Gy) were significantly better predictors of the actual lung absorbed doses than doses estimated on the basis of (166)Ho-microsphere planar scintigraphy (median 10.4 Gy, range 4.0 to 17.3 Gy; p < 0.001), (99m)Tc-MAA SPECT/CT imaging (median 2.5 Gy, range 1.2 to 12.3 Gy; p < 0.001), and (99m)Tc-MAA planar scintigraphy (median 5.5 Gy, range 2.3 to 18.2 Gy; p < 0.001). In clinical practice, lung absorbed doses are significantly overestimated by pretreatment diagnostic (99m)Tc-MAA imaging. Pretreatment diagnostic (166)Ho-microsphere SPECT/CT imaging accurately predicts lung absorbed doses after (166)Ho radioembolization.

Gene transfer as a strategy to achieve permanent cardioprotection II: rAAV-mediated gene therapy with heme oxygenase-1 limits infarct size 1 year later without adverse functional consequences.

PubMed

Li, Qianhong; Guo, Yiru; Ou, Qinghui; Wu, Wen-Jian; Chen, Ning; Zhu, Xiaoping; Tan, Wei; Yuan, Fangping; Dawn, Buddhadeb; Luo, Li; Hunt, Gregory N; Bolli, Roberto

2011-11-01

Extensive evidence indicates that heme oxygenase-1 (HO-1) exerts potent cytoprotective effects in response to stress. Previous studies have shown that gene therapy with HO-1 protects against myocardial ischemia/reperfusion injury for up to 8 weeks after gene transfer. However, the long-term effects of HO-1 gene therapy on myocardial ischemic injury and function are unknown. To address this issue, we created a recombinant adeno-associated viral vector carrying the HO-1 gene (rAAV/HO-1) that enables long-lasting transgene expression. Mice received injections in the anterior LV wall of rAAV/LacZ (LacZ group) or rAAV/HO-1 (HO-1 group); 1 year later, they were subjected to a 30-min coronary occlusion (O) and 4 h of reperfusion (R). Cardiac HO-1 gene expression was confirmed at 1 month and 1 year after gene transfer by immunoblotting and immunohistochemistry analyses. In the HO-1 group, infarct size (% of risk region) was dramatically reduced at 1 year after gene transfer (11.2 ± 2.1%, n = 12, vs. 44.7 ± 3.6%, n = 8, in the LacZ group; P < 0.05). The infarct-sparing effects of HO-1 gene therapy at 1 year were as powerful as those observed 24 h after ischemic PC (six 4-min O/4-min R cycles) (15.0 ± 1.7%, n = 10). There were no appreciable changes in LV fractional shortening, LV ejection fraction, or LV end-diastolic or end-systolic diameter at 1 year after HO-1 gene transfer as compared to the age-matched controls or with the LacZ group. Histology showed no inflammation in the myocardium 1 year after rAAV/HO-1-mediated gene transfer. These results demonstrate, for the first time, that rAAV-mediated HO-1 gene transfer confers long-term (1 year), possibly permanent, cardioprotection without adverse functional consequences, providing proof of principle for the concept of achieving prophylactic cardioprotection (i.e., "immunization against infarction").

Experimental Investigation on the Topotaxy of Sulfide and Silicate Melts in Peridotite: Implications for the Origin of PGE-depleted Cu-Ni Sulfide Deposit

NASA Astrophysics Data System (ADS)

Wang, Z.; Zhang, J.; Jin, Z.

2016-12-01

Cu-Ni sulfide deposit is generally considered partial melt originated from the mantle which is usually PGE-enriched. However, the largest Cu-Ni sulfide deposits of China (the Jinchuan Cu-Ni deposit) is PGE-depleted. Comparing to silicate melt, the nature and topotaxy of sulfide melt have remained poorly understood. Here we report experimental investigation on the topotaxy of sulfide and silicate melts in peridotite using a piston-cylinder press and a 5GPa Griggs-type deformation apparatus. The starting material consists of polycrystalline olivine or pyrolite and 1 wt% Fe-Ni-Cu sulfide. Hydrostatic and deformation experiments were conducted at a pressure of 1.5 GPa and a temperature of 1250°. Under hydrostatic conditions, our results reveal that the apparent dihedral angle of sulfide melt in an olivine matrix( 96°) is much larger than that of silicate + sulfide melt in pyrolite(<60°) under hydrostatic conditions. The sulfide melt pockets appear mostly as blobs in triple junctions with an immiscible Ni-poor center surrounded by a Ni-rich layer. Under deformation conditions, olivine develops pronounced fabrics with the pole of the (010) forming high concentrations approximately normal to the foliation plane and the [100] axes forming a girdle in the foliation plane. EBSD phase mapping analyses reveal strong shape preferred orientations (SPO) of sulfide +silicate melt in the 45, 90, 135 degree directions for deformation experiments indicating complete wetting of grain boundaries and forming a favorable source for ore deposits. Deformation also causes mixing of the Ni-rich and the Ni-poor sulfide melts. As the platinum-group elements(PGE) prefer to concentrate in the Ni-rich sulfide melt at high temperatures, our results suggest that the metallogenetic source of the PGE-depleted Cu-Ni deposits may have formed under relatively intense deformation and low temperatures with a small fraction of mixed sulfide and silicate melts.

Kinetic and Thermodynamic Characterization of the Cobalt and Manganese Oxyhydroxide Cores Formed in Horse Spleen Ferritin

NASA Technical Reports Server (NTRS)

Zhang, Bo; Harb, John N.; Davis, Robert C.; Kim, Jae-Woo; Chu, Sang-Hyon; Choi, Sang; Miller, Tim; Watt, Gerald D.

2004-01-01

Horse spleen ferritin (HoSF) containing 800-1500 cobalt or 250-1200 manganese atoms as Co(O)OH and Mn(O)OH mineral cores within the HoSF interior (Co-HoSF and Mn-HoSF) was synthesized, and the chemical reactivity, kinetics of reduction, and the reduction potentials were measured. Microcoulometric and chemical reduction of HoSF containing the M(O)OH mineral core (M = Co or Mn) was rapid and quantitative with a reduction stoichiometry of 1.05+/-0.10 e/M forming a stable M(OH)2 mineral core. At pH 9.0, ascorbic acid (AH2), a two-electron reductant, effectively reduced the mineral cores; however, the reaction was incomplete and rapidly reached equilibrium. The addition of excess AH2 shifted the reaction to completion with a M(3+)/AH2 stoichiometry of 1.9-2.1, consistent with a single electron per metal atom reduction. The rate of reaction between M(0)OH and excess AH2 was measured by monitoring the decrease in mineral core absorbance with time. The reaction was first order in each reactant with second-order rate constants of 0.53 and 4.74/M/min, respectively, for Co- and Mn-HoSF at pH 9.0. From the variation of absorbance with increasing AH2 concentration, equilibrium constants at pH 9.0 of 5.0+/-1.9 for Co-HoSF and 2.9+/-0.9 for Mn-HoSF were calculated for 2M(O)OH + AH2 = 2M(OH)2 f D, where AH2 and D are ascorbic acid and dehydroascorbic acid, respectively. Consistent with these equilibrium constants, the standard potential for the reduction of Co(III)-HoSF is 42 mV more positive than that of the ascorbic acid reaction, while the standard potential of Mn(III)-HoSF is 27 mV positive relative to AH2. Fe(2+) in solution with Co- and Mn-HoSF under anaerobic conditions was oxidized to form Fe(O)OH within the HoSF interior, resulting in partial displacement of the Co or Mn by iron.

Increased Plasma Levels of Heme Oxygenase-1 in Human Brucellosis.

PubMed

Chen, Zhe; Zhang, Yu-Xue; Fu, Dong-Wei; Gao, Qing-Feng; Ge, Feng-Xia; Liu, Wei-Hua

2016-08-01

Brucellosis is associated with inflammation and the oxidative stress response. Heme oxygenase-1 (HO-1) is a cytoprotective stress-responsive enzyme that has anti-inflammatory and anti-oxidant effects. Nevertheless, the role of HO-1 in human brucellosis has not yet been studied. The aim of this study was to examine the plasma levels of HO-1 in patients with brucellosis and to evaluate the ability of plasma HO-1 levels as an auxiliary diagnosis, a severity predictor, and a monitor for brucellosis treatments. A total of 75 patients with brucellosis were divided into the acute, subacute, chronic active, and chronic stable groups. An additional 20 volunteers were included as the healthy control group. The plasma HO-1 levels and other laboratory parameters were measured in all groups. Furthermore, the plasma levels of HO-1 in the acute group were compared before and after treatment. The plasma HO-1 levels were considerably increased in the acute (4.97 ± 3.55), subacute (4.98 ± 3.23), and chronic active groups (4.43 ± 3.00) with brucellosis compared to the healthy control group (1.03 ± 0.63) (p < 0.01). In the acute group, the plasma HO-1 levels in the post-treatment group (2.33 ± 2.39) were significantly reduced compared to the pre-treatment group (4.97 ± 3.55) (p < 0.01). On the other hand, the plasma HO-1 levels were higher in the chronic active group (4.43 ± 3.00) than the chronic stable group (2.74 ± 2.23) (p < 0.05). However, the plasma HO-1 levels in the chronic stable group (2.74 ± 2.23) remained higher than the levels in the healthy control group (1.03 ± 0.63) (p < 0.05). The HO-1 levels were positively correlated with the C-reactive protein (CRP) levels in patients with brucellosis (r = 0.707, p < 0.01). The plasma HO-1 levels can reflect patients' brucellosis status and may be used as a supplementary plasma marker for diagnosing brucellosis and monitoring its treatment.

Nutlin-3 induces HO-1 expression by activating JNK in a transcription-independent manner of p53.

PubMed

Choe, Yun-Jeong; Lee, Sun-Young; Ko, Kyung Won; Shin, Seok Joon; Kim, Ho-Shik

2014-03-01

A recent study reported that p53 can induce HO-1 by directly binding to the putative p53 responsive element in the HO-1 promoter. In this study, we report that nutlin-3, a small molecule antagonist of HDM2, induces the transcription of HO-1 in a transcription-independent manner of p53. Nutlin-3 induced HO-1 expression at the level of transcription in human cancer cells such as U2OS and RKO cells. This induction of HO-1 did not occur in SAOS cells in which p53 was mutated and was prevented by knocking down the p53 protein using p53 siRNA transfection, but not by PFT-α, an inhibitor of the transcriptional activity of p53. Accompanying HO-1 expression, nutlin-3 stimulated the accumulation of ROS and the phosphorylation of MAPKs such as JNK, p38 MAPK and ERK1/2. Nutlin-3-induced HO-1 expression was suppressed by TEMPO, a ROS scavenger, and chemical inhibitors of JNK and p38 MAPK but not ERK1/2. In addition, nutlin‑3-induced phosphorylation of JNK but not p38 MAPK was inhibited by TEMPO. Notably, the levels of nutlin-3-induced ROS were correlated with the mitochondrial translocation of p53 and this induction was prevented by PFT-μ, an inhibitor of the mitochondrial translocation of p53. Consistent with the effect of the ROS scavenger and MAPK inhibitors, PFT-μ reduced HO-1 expression and the phosphorylation of JNK induced by nutlin-3. In the experiments of analyzing cell death, the knockdown of HO-1 augmented nutlin-3-induced apoptosis. Collectively, these results suggest that nutlin-3 induces HO-1 expression via the activation of both JNK which is dependent on ROS generated by p53 translocated to the mitochondria and p38 MAPK which appears to be stimulated by a ROS-independent mechanism, and this HO-1 induction may inhibit nutlin-3-induced apoptosis, constituting a negative feedback loop of p53-induced apoptosis.

Identify changes of brain regional homogeneity in early and later adult onset patients with first-episode depression using resting-state fMRI.

PubMed

Shen, Zonglin; Jiang, Linling; Yang, Shuran; Ye, Jing; Dai, Nan; Liu, Xiaoyan; Li, Na; Lu, Jin; Liu, Fang; Lu, Yi; Sun, Xuejin; Cheng, Yuqi; Xu, Xiufeng

2017-01-01

Previous work exhibited different brain grey matter volume (GMV) changes between patients with early adult onset depression (EOD, age 18-29) and later adult onset depression (LOD, age 30-44) by using 30-year-old as the cut-off age. To identify whether regional homogeneity (ReHo) changes are also different between EOD and LOD by using same cut-off age, we used resting-state functional magnetic resonance imaging (fMRI) to detect the abnormal ReHo between patients with EOD and LOD in the present study. Resting-state fMRI scans of 58 patients with EOD, 62 patients with LOD, 60 young healthy controls (HC), and 52 old HC were obtained. The ReHo approach was used to analyze the images. The ANOVA analysis revealed that the ReHo values in the frontoparietal, occipital, and cerebellar regions were significantly different among the four groups. Relative to patients with LOD, patients with EOD displayed significantly increased ReHo in the left precuneus, and decreased ReHo in the right fusiform. The ReHo values in the left precuneus and the right fusiform had no significant correlation with the score of the depression rating scale or illness duration in both patient subgroups. Compared to young HC, patients with EOD showed significantly increased ReHo in the right frontoparietal regions and the right calcarine. Furthermore, the increased ReHo in the right frontoparietal regions, right insula and left hippocampus, and decreased ReHo in the left inferior occipital gyrus, right middle occipital gyrus, left calcarine, and left supplementary motor area were observed in patients with LOD when compared to old HC. The ReHo of brain areas that were related to mood regulation was changed in the first-episode, drug-naive adult patients with MDD. Adult patients with EOD and LOD exhibited different ReHo abnormalities relative to each age-matched comparison group, suggesting that depressed adult patients with different age-onset might have different pathological mechanism.

Prompt HO2 formation following the reaction of OH with aromatic compounds under atmospheric conditions.

PubMed

Nehr, Sascha; Bohn, Birger; Wahner, Andreas

2012-06-21

The secondary formation of HO(2) radicals following OH + aromatic hydrocarbon reactions in synthetic air under normal pressure and temperature was investigated in the absence of NO after pulsed production of OH radicals. OH and HO(x) (=OH + HO(2)) decay curves were recorded using laser-induced fluorescence after gas-expansion. The prompt HO(2) yields (HO(2) formed without preceding NO reactions) were determined by comparison to results obtained with CO as a reference compound. This approach was recently introduced and applied to the OH + benzene reaction and was extended here for a number of monocyclic aromatic hydrocarbons. The measured HO(2) formation yields are as follows: toluene, 0.42 ± 0.11; ethylbenzene, 0.53 ± 0.10; o-xylene, 0.41 ± 0.08; m-xylene, 0.27 ± 0.06; p-xylene, 0.40 ± 0.09; 1,2,3-trimethylbenzene, 0.31 ± 0.06; 1,2,4-trimethylbenzene, 0.37 ± 0.09; 1,3,5-trimethylbenzene, 0.29 ± 0.08; hexamethylbenzene, 0.32 ± 0.08; phenol, 0.89 ± 0.29; o-cresol, 0.87 ± 0.29; 2,5-dimethylphenol, 0.72 ± 0.12; 2,4,6-trimethylphenol, 0.45 ± 0.13. For the alkylbenzenes HO(2) is the proposed coproduct of phenols, epoxides, and possibly oxepins formed in secondary reactions with O(2). In most product studies the only quantified coproducts were phenols whereas only a few studies reported yields of epoxides. Oxepins have not been observed so far. Together with the yields of phenols from other studies, the HO(2) yields determined in this work set an upper limit to the combined yields of epoxides and oxepins that was found to be significant (≤0.3) for all investigated alkylbenzenes except m-xylene. For the hydroxybenzenes the currently proposed HO(2) coproducts are dihydroxybenzenes. For phenol and o-cresol the determined HO(2) yields are matching the previously reported dihydroxybenzene yields, indicating that these are the only HO(2) forming reaction channels. For 2,5-dimethylphenol and 2,4,6-trimethylphenol no complementary product studies are available.

Quantifying VOC-Reaction Tracers, Ozone Production, and Continuing Aerosol Production Rates in Urban and Far-Downwind Atmospheres

NASA Technical Reports Server (NTRS)

Chatfield, Robert; Ren, X.; Brune, W.; Fried, A.; Schwab, J.

2008-01-01

We have found a surprisingly informative decomposition of the complex question of smoggy ozone production (basically, [HO2] in a more locally determined field of [NO]) in the process of linked investigations of modestly smoggy Eastern North America (by NASA aircraft, July 2004) and rather polluted Flushing, NYC (Queens College, July, 2001). In both rural and very polluted situations, we find that a simple contour graph parameterization of the local principal ozone production rate can be estimated using only the variables [NO] and j(sub rads) [HCHO]: Po(O3) = c (j(sub rads) [HCHO])(sup a) [HCHO](sup b). Here j(sub rads) is the photolysis of HCHO to radicals, presumably capturing many harder-UV photolytic processes and the principle ozone production is that due to HO2; mechanisms suggest that ozone production due to RO2 is closely correlated, often suggesting a limited range of different proportionality factors. The method immediately suggests a local interpretation for concepts of VOC limitation and NOx limitation. We believe that the product j(sub rads) [HCHO] guages the oxidation rate of observed VOC mixtures in a way that also provides [HO2] useful for the principle ozone production rate k [HO2] [NO], and indeed, all ozone chemical production. The success of the method suggests that dominant urban primary-HCHO sources may transition to secondary plume-HCHO sources in a convenient way. Are there other, simple, near-terminal oxidized VOC's which help guage ozone production and aerosol particle formation? Regarding particles, we report on, to the extent NASA Research resources allow, on appealing relationships between far-downwind (Atlantic PBL) HCHO and very fine aerosol (including sulfate. Since j(sub rads) [HCHO] provides a time-scale, we may understand distant-plume particle production in a more quantitative manner. Additionally we report on a statistical search in the nearer field for relationships between glyoxals (important near-terminal aromatic and isoprene reaction products) and aerosol production, looking for VOC's that might be most implicated. All three variables j(sub rads), [HCHO], and [NO] are relatively easily measured in widespread air pollution monitoring networks, and all are deducible form space-borne observations, though estimation of [NO] from [NO2] (the species observable from space) may require care. We report also on airborne and surface observations of HCHO, suggesting that concentrated (urban) and more diffuse (forest) sources may be distinguishable from space. The use of the 3.58 micron microwindow for HCHO remote sensing should allow much sharper resolution of HCHO than the UV. UV sensing requires large and expensive instruments, but even these seem justified since formaldehyde is so informative.

Oxidative capacity of the Mexico City atmosphere - Part 1: A radical source perspective

NASA Astrophysics Data System (ADS)

Volkamer, R.; Sheehy, P.; Molina, L. T.; Molina, M. J.

2010-07-01

A detailed analysis of OH, HO2 and RO2 radical sources is presented for the near field photochemical regime inside the Mexico City Metropolitan Area (MCMA). During spring of 2003 (MCMA-2003 field campaign) an extensive set of measurements was collected to quantify time-resolved ROx (sum of OH, HO2, RO2) radical production rates from day- and nighttime radical sources. The Master Chemical Mechanism (MCMv3.1) was constrained by measurements of (1) concentration time-profiles of photosensitive radical precursors, i.e., nitrous acid (HONO), formaldehyde (HCHO), ozone (O3), glyoxal (CHOCHO), and other oxygenated volatile organic compounds (OVOCs); (2) respective photolysis-frequencies (J-values); (3) concentration time-profiles of alkanes, alkenes, and aromatic VOCs (103 compound are treated) and oxidants, i.e., OH- and NO3 radicals, O3; and (4) NO, NO2, meteorological and other parameters. The ROx production rate was calculated directly from these observations; the MCM was used to estimate further ROx production from unconstrained sources, and express overall ROx production as OH-equivalents (i.e., taking into account the propagation efficiencies of RO2 and HO2 radicals into OH radicals). Daytime radical production is found to be about 10-25 times higher than at night; it does not track the abundance of sunlight. 12-h average daytime contributions of individual sources are: Oxygenated VOC other than HCHO about 33%; HCHO and O3 photolysis each about 20%; O3/alkene reactions and HONO photolysis each about 12%, other sources <3%. Nitryl chloride photolysis could potentially contribute ~15% additional radicals, while NO2* + water makes - if any - a very small contribution (~2%). The peak radical production of ~7.5 107 molec cm-3 s-1 is found already at 10:00 a.m., i.e., more than 2.5 h before solar noon. O3/alkene reactions are indirectly responsible for ~33% of these radicals. Our measurements and analysis comprise a database that enables testing of the representation of radical sources and radical chain reactions in photochemical models. Since the photochemical processing of pollutants in the MCMA is radical limited, our analysis identifies the drivers for ozone and SOA formation. We conclude that reductions in VOC emissions provide an efficient opportunity to reduce peak concentrations of these secondary pollutants, because (1) about 70% of radical production is linked to VOC precursors; (2) lowering the VOC/NOx ratio has the further benefit of reducing the radical re-cycling efficiency from radical chain reactions (chemical amplification of radical sources); (3) a positive feedback is identified: lowering the rate of radical production from organic precursors also reduces that from inorganic precursors, like ozone, as pollution export from the MCMA caps the amount of ozone that accumulates at a lower rate inside the MCMA. Continued VOC reductions will in the future result in decreasing peak concentrations of ozone and SOA in the MCMA.

Reuse of Fenton sludge as an iron source for NiFe2O4 synthesis and its application in the Fenton-based process.

PubMed

Zhang, Hui; Liu, Jianguo; Ou, Changjin; Faheem; Shen, Jinyou; Yu, Hongxia; Jiao, Zhenhuan; Han, Weiqing; Sun, Xiuyun; Li, Jiansheng; Wang, Lianjun

2017-03-01

The potentially hazardous iron-containing sludge from the Fenton process requires proper treatment and disposal, which often results in high treatment cost. In this study, a novel method for the reuse of Fenton sludge as an iron source for the synthesis of nickel ferrite particles (NiFe 2 O 4 ) is proposed. Through a co-precipitation method followed by sintering at 800°C, magnetic NiFe 2 O 4 particles were successfully synthesized, which was confirmed by powder X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The synthesized NiFe 2 O 4 could be used as an efficient catalyst in the heterogeneous Fenton process. In phenol degradation with H 2 O 2 or NiFe 2 O 4 alone, the phenol removal efficiencies within the reaction time of 330min were as low as 5.9%±0.1% and 13.5%±0.4%, respectively. However, in the presence of both NiFe 2 O 4 and H 2 O 2 , phenol removal efficiency as high as 95%±3.4% could be achieved, indicating the excellent catalytic performance of NiFe 2 O 4 in the heterogeneous Fenton process. Notably, a rapid electron exchange between Ni II and Fe III ions in the NiFe 2 O 4 structure could be beneficial for the Fenton reaction. In addition, the magnetic catalyst was relatively stable, highly active and recoverable, and has potential applications in the Fenton process for organic pollutant removal. Copyright © 2016. Published by Elsevier B.V.

Can preoperative detrusor underactivity influence surgical outcomes of 120 W HPS vaporization of the prostate (PVP) or holmium laser enucleation of the prostate (HoLEP)? A serial 3-year follow-up study.

PubMed

Cho, Min Chul; Park, Juhyun; Kim, Jung Kwon; Cho, Sung Yong; Jeong, Hyeon; Oh, Seung-June; Paick, Jae-Seung; Son, Hwancheol

2018-01-01

To determine the influence of preoperative detrusor underactivity (DU) on serial long-term outcomes of HPS/PVP or HoLEP for LUTS/BPH, and to compare the influence between the two surgeries. A total of 382 men, who underwent 120W-HPS/PVP or HoLEP for LUTS/BPH and for whom 36-month follow-up data were available, were classified into four groups: HPS with DU (n = 145), HPS without DU (n = 44), HoLEP with DU (n = 105), and HoLEP without DU (n = 88). DU was defined as bladder contractility index of <100. Surgical outcomes were assessed at postoperative 6, 12, 24, and 36 months using IPSS, uroflowmetry, and serum PSA. All four groups maintained improvements in voiding symptom score (VSS), storage symptom score, total-IPSS, QOL index, maximum flow rate (Qmax), post-void residual urine volume (PVR), and bladder voiding efficiency (BVE) compared with baseline up to 3 years postoperatively. There were no significant differences in improvements of postoperative IPSS parameters including QOL index between men with and without DU throughout the follow-up period after HPS or HoLEP. In men with DU, there were no significant differences in improvements of postoperative QOL index, Qmax, PVR, or BVE between HPS and HoLEP groups throughout the follow-up period, except for VSS and total IPSS. Serum PSA reductions after HoLEP were greater than after PVP. Improvements in LUTS, Qmax, and BVE can maintain up to 3 years after HPS or HoLEP for LUTS/BPH, irrespective of the presence or absence of preoperative DU. Although HoLEP may provide more durable improvement of VS in men with DU than HPS, there seems to be no difference in improvement of QOL or Qmax or BVE between HPS and HoLEP. © 2017 Wiley Periodicals, Inc.

Infiltration of myeloid cells in the pregnant uterus is affected by heme oxygenase-1.

PubMed

Zhao, Hui; Kalish, Flora; Wong, Ronald J; Stevenson, David K

2017-01-01

Infiltrating myeloid cells in pregnant uteri play critical roles in the establishment of the placenta and maintenance of normal pregnancies. Their recruitment and proliferation are primarily mediated by the interactions of cytokines and chemokines secreted locally with their corresponding receptors. Heme oxygenase-1 (HO-1) has various physiologic properties that contribute to placental vascular development, with deficiencies in HO-1 associated with pregnancy disorders. Here, we investigated the effect of HO-1 on myeloid cell infiltration into pregnant uteri using a partial HO-1-deficient (Het, HO-1 +/- ) mouse model. With the use of flow cytometry, HO-1 was found predominantly expressed in circulating and uterine myeloid cells, specifically neutrophils and monocytes/macrophages. In pregnant Het uteri, the numbers of neutrophils and monocytes/macrophages were significantly reduced compared with pregnant wild-type (WT; HO-1 +/+ ) uteri. With the use of BrdU in vivo assays, HO-1 deficiency did not affect cell proliferation or blood cell populations. With the use of PCR arrays, gene expression of cytokines (Csf1, Csf3), chemokines (Ccl1, Ccl2, Ccl6, Ccl8, Ccl11, Ccl12, Cxcl4, Cxcl9, Cxcl12), and their receptors (Ccr1, Ccr2, Ccr3, Ccr5) were also reduced significantly in Het compared with pregnant WT uteri. Moreover, with the use of flow cytometry, myeloid CSF1R and CCR2 expression in blood and uteri from both pregnant and nonpregnant mice was characterized, and a deficiency in HO-1 significantly reduced CCR2 expression in infiltrating uterine monocytes/macrophages and dendritic cells (DCs). These data reveal that HO-1 regulates not only cytokine/chemokine production in pregnant uteri but also myeloid cell receptor numbers, suggesting a role of HO-1 in the recruitment and maintenance of myeloid cells in pregnant uteri and subsequent effects on placental vascular formation. © Society for Leukocyte Biology.

The Impact of Body Mass Index on Heterotopic Ossification

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

Mourad, Waleed Fouad, E-mail: Waleed246@gmail.com; Department of Radiation Oncology, Beth Israel Medical Center, New York, NY; Department of Radiation Oncology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY

2012-04-01

Purpose: To analyze the impact of different body mass index (BMI) as a surrogate marker for heterotopic ossification (HO) in patients who underwent surgical repair (SR) for displaced acetabular fractures (DAF) followed by radiation therapy (RT). Methods and Materials: This is a single-institution retrospective study of 395 patients. All patients underwent SR for DAF followed by RT {+-} indomethacin. All patients received postoperative RT, 7 Gy, within 72 h. The patients were separated into four groups based on their BMI: <18.5, 18.5-24.9, 25-29.9, and >30. The end point of this study was to evaluate the efficacy of RT {+-} indomethacinmore » in preventing HO in patients with different BMI. Results: Analysis of BMI showed an increasing incidence of HO with increasing BMI: <18.5, (0%) 0/6 patients; 18.5-24.9 (6%), 6 of 105 patients developed HO; 25-29.9 (19%), 22 of 117; >30 (31%), 51 of 167. Chi-square and multivariate logistic regression analysis showed that the correlation between odds of HO and BMI is significant, p < 0.0001. As the BMI increased, the risk of HO and Brooker Classes 3, 4 HO increased. The risk of developing HO is 1.0 Multiplication-Sign (10%) more likely among those with higher BMI compared with those with lower BMI. For a one-unit increase in BMI the log odds of HO increases by 1.0, 95% CI (1.06-1.14). Chi-square test shows no significant difference among all other factors and HO (e.g., indomethacin, race, gender). Conclusions: Despite similar surgical treatment and prophylactic measures (RT {+-} indomethacin), the risk of HO appears to significantly increase in patients with higher BMI after DAF. Higher single-fraction doses or multiple fractions and/or combination therapy with nonsteroidal inflammatory drugs may be of greater benefit to these patients.« less

Compound C Stimulates Heme Oxygenase-1 Gene Expression via the Nrf2-ARE Pathway to Preserve Human Endothelial Cell Survival

PubMed Central

Liu, Xiao-ming; Peyton, Kelly J.; Shebib, Ahmad R.; Wang, Hong; Durante, William

2011-01-01

We recently identified adenosine monophosphate-activated protein kinase (AMPK) as a novel inducer of heme oxygenase-1 (HO-1) and surprisingly found that compound C (6-[4-(2-piperidin-1-yl-ethoxy)-phenyl]3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine), a cell-permeable inhibitor of AMPK, could also elevate HO-1 suggesting other AMPK-independent actions for this agent. In this study, we investigated the biochemical mechanism by which compound C stimulates HO-1 expression in human endothelial cells (ECs) and determined the biological significance of the induction of HO-1 by compound C in these cells. Compound C stimulated a concentration- and time-dependent increase in HO-1 expression and an increase in HO-1 promoter activity that was abrogated by mutating the antioxidant responsive elements (AREs) in the HO-1 promoter or by overexpressing a dominant negative mutant of NF-E2-related factor-2 (Nrf2). Compound C also stimulated Nrf2 expression and this was associated with an increase in the production of reactive oxygen species and with a decline in intracellular glutathione levels. Interestingly, the glutathione donor N-acetyl-L-cysteine or the NADPH oxidase inhibitor apocynin blocked the induction of HO-1 by compound C. Finally, compound C stimulated EC death and this was potentiated by silencing HO-1 expression and reversed by the administration of CO, biliverdin, or bilirubin. In conclusion, this study demonstrates that compound C stimulates HO-1 gene expression in human vascular endothelium via the activation of the Nrf2/ARE signaling pathway to counteract compound C-mediated cell death. The ability of compound C to induce HO-1 expression may contribute to the pleiotropic actions of this agent and suggest caution when using compound C to probe for AMPK functions. PMID:21635873

Heme oxygenase-1 gene expression modulates angiotensin II-induced increase in blood pressure.

PubMed

Yang, Liming; Quan, Shuo; Nasjletti, Alberto; Laniado-Schwartzman, Michal; Abraham, Nader G

2004-06-01

The heme-heme oxygenase (HO) system has been implicated in the regulation of vascular reactivity and blood pressure. This study examines the notion that overexpression of HO decreases pressor responsiveness to angiotensin II (Ang II). Five-day-old Sprague-Dawley rats received an intraleft ventricular injection of approximately 5x10(9) cfu/mL of retroviruses containing human HO-1 sense (LSN-HHO-1), rat HO-1 antisense (LSN-RHO-1-AS), or control retrovirus (LXSN). Three months later, rats were instrumented with femoral arterial and venous catheters for mean arterial pressure (MAP) determination and Ang II administration, respectively. Rats injected with LSN-HHO-1, but not with LXSN, expressed human HO-1 mRNA and protein in several tissues. BP increased with administration of Ang II in rats expressing and not expressing human HO-1. However, the Ang II-induced pressor response (mm Hg) in LSN-HHO-1 rats (16+/-3, 27+/-3, and 38+/-3 at 0.5, 2, and 10 ng) was surpassed (P<0.05) in LXSN rats (23+/-1, 37+/-2, and 52+/-2 at 0.5, 2, and 10 ng). Importantly, treating LSN-HHO-1 rats with the HO inhibitor tin mesoporphyrin (SnMP) enhanced (P<0.05) the Ang II-induced pressor response to a level not different from that observed in LXSN rats. Rats injected with LSN-RHO-1-AS showed a decrease in renal HO-1 protein expression and HO activity relative to control LXSN rats. Administration of Ang II (0.1 to 2 ng) caused small (4 to 5 mm Hg) but significant increases in MAP in rats injected with LSN-RHO-1-AS (P<0.05) compared with rats injected with LXSN. These data demonstrate that overexpression of HO-1 brings about a reduction in pressor responsiveness to Ang II, which is most likely due to increased generation of an HO-1 product, presumably CO, with the ability to inhibit vascular reactivity to constrictor stimuli.

Ammonia promotes endothelial cell survival via the heme oxygenase-1-mediated release of carbon monoxide.

PubMed

Liu, Xiao-Ming; Peyton, Kelly J; Durante, William

2017-01-01

Although endothelial cells produce substantial quantities of ammonia during cell metabolism, the physiologic role of this gas in these cells is not known. In this study, we investigated if ammonia regulates the expression of heme oxygenase-1 (HO-1), and if this enzyme influences the biological actions of ammonia on endothelial cells. Exogenously administered ammonia, given as ammonium chloride or ammonium hydroxide, or endogenously generated ammonia stimulated HO-1 protein expression in cultured human and murine endothelial cells. Dietary supplementation of ammonia also induced HO-1 protein expression in murine arteries. The increase in HO-1 protein by ammonia in endothelial cells was first detected 4h after ammonia exposure and was associated with the induction of HO-1 mRNA, enhanced production of reactive oxygen species (ROS), and increased expression and activity of NF-E2-related factor-2 (Nrf2). Ammonia also activated the HO-1 promoter and this was blocked by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. The induction of HO-1 expression by ammonia was dependent on ROS formation and prevented by N-acetylcysteine or rotenone. Finally, prior treatment of endothelial cells with ammonia inhibited tumor necrosis factor-α-stimulated cell death. However, silencing HO-1 expression abrogated the protective action of ammonia and this was reversed by the administration of carbon monoxide but not bilirubin or iron. In conclusion, this study demonstrates that ammonia stimulates the expression of HO-1 in endothelial cells via the ROS-Nrf2 pathway, and that the induction of HO-1 contributes to the cytoprotective action of ammonia by generating carbon monoxide. Moreover, it identifies ammonia as a potentially important signaling gas in the vasculature that promotes endothelial cell survival. Copyright © 2016 Elsevier Inc. All rights reserved.

Physiological cyclic strain promotes endothelial cell survival via the induction of heme oxygenase-1

PubMed Central

Liu, Xiao-ming; Peyton, Kelly J.

2013-01-01

Endothelial cells (ECs) are constantly subjected to cyclic strain that arises from periodic change in vessel wall diameter as a result of pulsatile blood flow. Application of physiological levels of cyclic strain inhibits EC apoptosis; however, the underlying mechanism is not known. Since heme oxygenase-1 (HO-1) is a potent inhibitor of apoptosis, the present study investigated whether HO-1 contributes to the antiapoptotic action of cyclic strain. Administration of physiological cyclic strain (6% at 1 Hz) to human aortic ECs stimulated an increase in HO-1 activity, protein, and mRNA expression. The induction of HO-1 was preceded by a rise in reactive oxygen species (ROS) and Nrf2 protein expression. Cyclic strain also stimulated an increase in HO-1 promoter activity that was prevented by mutating the antioxidant responsive element in the promoter or by overexpressing dominant-negative Nrf2. In addition, the strain-mediated induction of HO-1 and activation of Nrf2 was abolished by the antioxidant N-acetyl-l-cysteine. Finally, application of cyclic strain blocked inflammatory cytokine-mediated EC death and apoptosis. However, the protective action of cyclic strain was reversed by the HO inhibitor tin protoporphyrin-IX and was absent in ECs isolated from HO-1-deficient mice. In conclusion, the present study demonstrates that a hemodynamically relevant level of cyclic strain stimulates HO-1 gene expression in ECs via the ROS-Nrf2 signaling pathway to inhibit EC death. The ability of cyclic strain to induce HO-1 expression may provide an important mechanism by which hemodynamic forces promote EC survival and vascular homeostasis. PMID:23604711

The expression of heme oxygenase-1 and inducible nitric oxide synthase in aorta during the development of hypertension in spontaneously hypertensive rats.

PubMed

Cheng, Pao-Yun; Chen, Jin-Jer; Yen, Mao-Hsiung

2004-12-01

The aim of this study was to observe the time-course changes of heme oxygenase-1 (HO-1) and inducible nitric oxide synthase (iNOS) induction in aorta during the development of hypertension, as well as the relationship of HO-1/carbon monoxide (CO) system and iNOS/nitric oxide (NO) system in spontaneously hypertensive rats (SHR). The systolic blood pressure (SBP) was determined in conscious rats by the tail-cuff method. The tissue HO-1 and iNOS mRNA and protein levels were estimated with reverse transcription polymerase chain reaction and Western blot method. The expression of HO-1 and iNOS in aorta increased with the SBP elevation during the development of SHR and was attenuated when the hypertension was lowered with the vasodilator hydralazine. At 8 weeks, only HO-1 was induced, whereas at 12 and 16 weeks, both HO-1 and iNOS were observed. The level of plasma nitrite/nitrate was associated with the change in iNOS expression in SHR. In addition, the SBP of 8-week-old SHR was significantly increased after pretreatment with zinc protoporphyrin IX for 7 consecutive days. Chronic blockade of iNOS activity by aminoguanidine resulted in significant up-regulation of HO-1, but the pressor effect was blunt. These results suggest that the up-regulation of HO-1 and iNOS in aorta is a compensatory mechanism for the elevation of SBP during the development of hypertension in SHR. The expression of HO-1 is earlier than that of iNOS. Our data suggest that the HO-1/CO system takes over and acts as a major modulator for the regulation of SBP when the iNOS/NO system is suppressed.

Measurement of interferences associated with the detection of the hydroperoxy radical in the atmosphere using laser-induced fluorescence

NASA Astrophysics Data System (ADS)

Lew, Michelle M.; Dusanter, Sebastien; Stevens, Philip S.

2018-01-01

One technique used to measure concentrations of the hydroperoxy radical (HO2) in the atmosphere involves chemically converting it to OH by addition of NO and subsequent detection of OH. However, some organic peroxy radicals (RO2) can also be rapidly converted to HO2 (and subsequently OH) in the presence of NO, interfering with measurements of ambient HO2 radical concentrations. This interference must be characterized for each instrument to determine to what extent various RO2 radicals interfere with measurements of HO2 and to assess the impact of this interference on past measurements. The efficiency of RO2-to-HO2 conversion for the Indiana University laser-induced fluorescence-fluorescence assay by gas expansion (IU-FAGE) instrument was measured for a variety of RO2 radicals. Known quantities of OH and HO2 radicals were produced from the photolysis of water vapor at 184.9 nm, and RO2 radicals were produced by the reaction of several volatile organic compounds (VOCs) with OH. The conversion efficiency of RO2 radicals to HO2 was measured when NO was added to the sampling cell for conditions employed during several previous field campaigns. For these conditions, approximately 80 % of alkene-derived RO2 radicals and 20 % of alkane-derived RO2 radicals were converted to HO2. Based on these measurements, interferences from various RO2 radicals contributed to approximately 35 % of the measured HO2 signal during the Mexico City Metropolitan Area (MCMA) 2006 campaign (MCMA-2006), where the measured VOCs consisted of a mixture of saturated and unsaturated species. However, this interference can contribute more significantly to the measured HO2 signal in forested environments dominated by unsaturated biogenic emissions such as isoprene.

Downregulation of Heme Oxygenase 1 (HO-1) Activity in Hematopoietic Cells Enhances Their Engraftment After Transplantation.

PubMed

Adamiak, Mateusz; Moore, Joseph B; Zhao, John; Abdelbaset-Ismail, Ahmed; Grubczak, Kamil; Rzeszotek, Sylwia; Wysoczynski, Marcin; Ratajczak, Mariusz Z

2016-01-01

Heme oxygenase 1 (HO-1) is an inducible stress-response enzyme that not only catalyzes the degradation of heme (e.g., released from erythrocytes) but also has an important function in various physiological and pathophysiological states associated with cellular stress, such as ischemic/reperfusion injury. HO-1 has a well-documented anti-inflammatory potential, and HO-1 has been reported to have a negative effect on adhesion and migration of neutrophils in acute inflammation in a model of peritonitis. This finding is supported by our recent observation that hematopoietic stem progenitor cells (HSPCs) from HO-1 KO mice are easy mobilizers, since they respond better to peripheral blood chemotactic gradients than wild-type littermates. Based on these findings, we hypothesized that transient inhibition of HO-1 by nontoxic small-molecule inhibitors would enhance migration of HSPCs in response to bone marrow chemoattractants and thereby facilitate their homing. To directly address this issue, we generated several human hematopoietic cell lines in which HO-1 was upregulated or downregulated. We also exposed murine and human BM-derived cells to small-molecule activators and inhibitors of HO-1. Our results indicate that HO-1 is an inhibitor of hematopoietic cell migration in response to crucial BM homing chemoattractants such as stromal-derived factor 1 (SDF-1) and sphingosine-1-phosphate (S1P). Most importantly, our in vitro and in vivo animal experiments demonstrate for the first time that transiently inhibiting HO-1 activity in HSPCs by small-molecule inhibitors improves HSPC engraftment. We propose that this simple and inexpensive strategy could be employed in the clinical setting to improve engraftment of HSPCs, particularly in those situations in which the number of HSPCs available for transplant is limited (e.g., when transplanting umbilical cord blood).

Heme oxygenase up-regulation under ultraviolet-B radiation is not epigenetically restricted and involves specific stress-related transcriptions factors.

PubMed

Santa-Cruz, Diego; Pacienza, Natalia; Zilli, Carla; Pagano, Eduardo; Balestrasse, Karina; Yannarelli, Gustavo

2017-08-01

Heme oxygenase-1 (HO-1) plays a protective role against oxidative stress in plants. The mechanisms regulating its expression, however, remain unclear. Here we studied the methylation state of a GC rich HO-1 promoter region and the expression of several stress-related transcription factors (TFs) in soybean plants subjected to ultraviolet-B (UV-B) radiation. Genomic DNA and total RNA were isolated from leaves of plants irradiated with 7.5 and 15kJm-2 UV-B. A 304bp HO-1 promoter region was amplified by PCR from sodium bisulfite-treated DNA, cloned into pGEMT plasmid vector and evaluated by DNA sequencing. Bisulfite sequencing analysis showed similar HO-1 promoter methylation levels in control and UV-B-treated plants (C: 3.4±1.3%; 7.5: 2.6±0.5%; 15: 3.1±1.1%). Interestingly, HO-1 promoter was strongly unmethylated in control plants. Quantitative RT-PCR analysis of TFs showed that GmMYB177, GmMYBJ6, GmWRKY21, GmNAC11, GmNAC20 and GmGT2A but not GmWRK13 and GmDREB were induced by UV-B radiation. The expression of several TFs was also enhanced by hemin, a potent and specific HO inducer, inferring that they may mediate HO-1 up-regulation. These results suggest that soybean HO-1 gene expression is not epigenetically regulated. Moreover, the low level of HO-1 promoter methylation suggests that this antioxidant enzyme can rapidly respond to environmental stress. Finally, this study has identified some stress-related TFs involved in HO-1 up-regulation under UV-B radiation. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Heme oxygenase-1-derived bilirubin counteracts HIV protease inhibitor-mediated endothelial cell dysfunction

PubMed Central

Liu, Xiao-Ming; Durante, Zane E.; Peyton, Kelly J.; Durante, William

2016-01-01

The use of HIV protease inhibitors (PIs) has extended the duration and quality of life for HIV-positive individuals. However there is increasing concern that this antiviral therapy may promote premature cardiovascular disease by impairing endothelial cell (EC) function. In the present study, we investigated the effect of HIV PIs on EC function and determined if the enzyme heme oxygenase (HO-1) influences the biological action of these drugs. We found that three distinct PIs, including ritonavir, atazanavir, and lopinavir, stimulated the expression of HO-1 protein and mRNA. The induction of HO-1 was associated with an increase in NF-E2-related factor-2 (Nrf2) activity and reactive oxygen species (ROS). PIs also stimulated HO-1 promoter activity and this was prevented by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. In addition, the PI-mediated induction of HO-1 was abolished by N-acetyl-L-cysteine and rotenone. Furthermore, PIs blocked EC proliferation and migration and stimulated the expression of intercellular adhesion molecule-1 and the adhesion of monocytes on ECs. Inhibition of HO-1 activity or expression potentiated the anti-proliferative and inflammatory actions of PIs which was reversed by bilirubin but not carbon monoxide. Alternatively, adenovirus-mediated overexpression of HO-1 attenuated the growth-inhibitory and inflammatory effect of PIs. In contrast, blocking HO-1 activity failed to modify the anti-migratory effect of the PIs. Thus, induction of HO-1 via the ROS–Nrf2 pathway in human ECs counteracts the anti-proliferative and inflammatory actions of PIs by generating bilirubin. Therapeutic approaches targeting HO-1 may provide a novel approach in preventing EC dysfunction and vascular disease in HIV-infected patients undergoing antiretroviral therapy. PMID:26968795

Hypochlorous acid-induced heme oxygenase-1 gene expression promotes human endothelial cell survival

PubMed Central

Wei, Yong; Liu, Xiao-ming; Peyton, Kelly J.; Wang, Hong; Johnson, Fruzsina K.; Johnson, Robert A.

2009-01-01

Hypochlorous acid (HOCl) is a unique oxidant generated by the enzyme myeloperoxidase that contributes to endothelial cell dysfunction and death in atherosclerosis. Since myeloperoxidase localizes with heme oxygenase-1 (HO-1) in and around endothelial cells of atherosclerotic lesions, the present study investigated whether there was an interaction between these two enzymes in vascular endothelium. Treatment of human endothelial cells with the myeloperoxidase product HOCl stimulated a concentration- and time-dependent increase in HO-1 protein that resulted in a significant rise in carbon monoxide (CO) production. The induction of HO-1 protein was preceded by a prominent increase in HO-1 mRNA and total and nuclear factor-erythroid 2-related factor 2 (Nrf2). In addition, HOCl induced a significant rise in HO-1 promoter activity that was blocked by mutating the antioxidant response element (ARE) in the promoter or by overexpressing a dominant-negative mutant of Nrf2. The HOCl-mediated induction of Nrf2 or HO-1 was blocked by the glutathione donor N-acetyl-l-cysteine but was unaffected by ascorbic or uric acid. Finally, treatment of endothelial cells with HOCl stimulated mitochondrial dysfunction, caspase-3 activation, and cell death that was potentiated by the HO inhibitor, tin protoporphyrin-IX, or by the knockdown of HO-1, and reversed by the exogenous administration of biliverdin, bilirubin, or CO. These results demonstrate that HOCl induces HO-1 gene transcription via the activation of the Nrf2/ARE pathway to counteract HOCl-mediated mitochondrial dysfunction and cell death. The ability of HOCl to activate HO-1 gene expression may represent a critical adaptive response to maintain endothelial cell viability at sites of vascular inflammation and atherosclerosis. PMID:19625608

Design of metal cofactors activated by a protein–protein electron transfer system

PubMed Central

Ueno, Takafumi; Yokoi, Norihiko; Unno, Masaki; Matsui, Toshitaka; Tokita, Yuichi; Yamada, Masako; Ikeda-Saito, Masao; Nakajima, Hiroshi; Watanabe, Yoshihito

2006-01-01

Protein-to-protein electron transfer (ET) is a critical process in biological chemistry for which fundamental understanding is expected to provide a wealth of applications in biotechnology. Investigations of protein–protein ET systems in reductive activation of artificial cofactors introduced into proteins remains particularly challenging because of the complexity of interactions between the cofactor and the system contributing to ET. In this work, we construct an artificial protein–protein ET system, using heme oxygenase (HO), which is known to catalyze the conversion of heme to biliverdin. HO uses electrons provided from NADPH/cytochrome P450 reductase (CPR) through protein–protein complex formation during the enzymatic reaction. We report that a FeIII(Schiff-base), in the place of the active-site heme prosthetic group of HO, can be reduced by NADPH/CPR. The crystal structure of the Fe(10-CH2CH2COOH-Schiff-base)·HO composite indicates the presence of a hydrogen bond between the propionic acid carboxyl group and Arg-177 of HO. Furthermore, the ET rate from NADPH/CPR to the composite is 3.5-fold faster than that of Fe(Schiff-base)·HO, although the redox potential of Fe(10-CH2CH2COOH-Schiff-base)·HO (−79 mV vs. NHE) is lower than that of Fe(Schiff-base)·HO (+15 mV vs. NHE), where NHE is normal hydrogen electrode. This work describes a synthetic metal complex activated by means of a protein–protein ET system, which has not previously been reported. Moreover, the result suggests the importance of the hydrogen bond for the ET reaction of HO. Our Fe(Schiff-base)·HO composite model system may provide insights with regard to design of ET biosystems for sensors, catalysts, and electronics devices. PMID:16769893

Small molecule activators of the Nrf2-HO-1 antioxidant axis modulate heme metabolism and inflammation in BV2 microglia cells.

PubMed

Foresti, Roberta; Bains, Sandip K; Pitchumony, Tamil Selvi; de Castro Brás, Lisandra E; Drago, Filippo; Dubois-Randé, Jean-Luc; Bucolo, Claudio; Motterlini, Roberto

2013-10-01

The nuclear factor erythroid derived 2-related factor 2 (Nrf2) and the antioxidant protein heme oxygenase-1 (HO-1) are crucial components of the cellular stress response. These two systems work together to combat oxidative stress and inflammation and are attractive drug targets for counteracting different pathologies, including neuroinflammation. We aimed to identify the most effective Nrf2/HO-1 activators that modulate the inflammatory response in microglia cells. In the present study, we searched the literature and selected 56 compounds reported to activate Nrf2 or HO-1 and analyzed them for HO-1 induction at 6 and 24h and cytotoxicity in BV2 microglial cells in vitro. Approximately 20 compounds up-regulated HO-1 at the concentrations tested (5-20 μM) with carnosol, supercurcumin, cobalt protoporphyrin-IX and dimethyl fumarate exhibiting the best induction/low cytotoxicity profile. Up-regulation of HO-1 by some compounds resulted in increased cellular bilirubin levels but did not augment the expression of proteins involved in heme synthesis (ALAS 1) or biliverdin reductase. Bilirubin production by HO-1 inducers correlated with their potency in inhibiting nitrite production after challenge with interferon-γ (INF-γ) or lipopolysaccharide (LPS). The compounds down-regulated the inflammatory response (TNF-α, PGE2 and nitrite) more strongly in cells challenged with INF-γ than LPS, and silencing HO-1 or Nrf2 with shRNA differentially affected the levels of inflammatory markers. These findings indicate that some small activators of Nrf2/HO-1 are effective modulators of microglia inflammation and highlight the chemical scaffolds that can serve for the synthesis of potent new derivatives to counteract neuroinflammation and neurodegeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reduced caveolin-1 promotes hyper-inflammation due to abnormal heme oxygenase-1 localizationin LPS challenged macrophages with dysfunctional CFTR

PubMed Central

Zhang, Ping-Xia; Murray, Thomas S.; Villella, Valeria Rachela; Ferrari, Eleonora; Esposito, Speranza; D'Souza, Anthony; Raia, Valeria; Maiuri, Luigi; Krause, Diane S.; Egan, Marie E.; Bruscia, Emanuela M.

2013-01-01

We have previously reported that TLR4 signaling is increased in lipopolysaccharide (LPS) -stimulated Cystic Fibrosis (CF) macrophages (MΦs), contributing to the robust production of pro-inflammatory cytokines. The heme oxygenase (HO-1)/carbon monoxide (CO) pathway modulates cellular redox status, inflammatory responses, and cell survival. The HO-1 enzyme, together with the scaffold protein caveolin 1 (CAV-1), also acts as a negative regulator of TLR4 signaling in MΦs. Here, we demonstrate that in LPS-challenged CF MΦs, HO-1 does not compartmentalize normally to the cell surface and instead accumulates intracellularly. The abnormal HO-1 localization in CF MΦs in response to LPS is due to decreased CAV-1 expression, which is controlled by the cellular oxidative state, and is required for HO-1 delivery to the cell surface. Overexpression of HO-1 or stimulating the pathway with CO-releasing molecules (CORM2)enhancesCAV-1 expression in CF MΦs, suggesting a positive-feed forward loop between HO-1/CO induction and CAV-1 expression. These manipulations reestablished HO-1 and CAV-1 cell surface localization in CF MΦ's. Consistent with restoration of HO-1/CAV-1 negative regulation of TLR4 signaling, genetic or pharmacological (CORM2)-induced enhancement of this pathway decreased the inflammatory response of CF MΦs and CF mice treated with LPS. In conclusion, our results demonstrate that the counter-regulatory HO-1/CO pathway, which is critical in balancing and limiting the inflammatory response, is defective in CF MΦs through a CAV-1-dependent mechanism, exacerbating the CF MΦ's response to LPS. This pathway could be a potential target for therapeutic intervention for CF lung disease. PMID:23606537

Facile preparation of Ni nanowire embedded nitrogen and sulfur dual-doped carbon nanofibers and its superior catalytic activity toward urea oxidation.

PubMed

Liu, Dong; Li, Wenjia; Li, Libo; Ling, Hao; You, Tianyan

2018-06-08

A novel hairy-shaped Ni nanowire embedded nitrogen and sulfur dual-doped carbon nanofibers (Ni/N,S-CNFs) with superior electrocatalytic properties for urea oxidation reaction (UOR) was reported. The Ni/N,S-CNFs was prepared by electrospinning and carbonization process, using melamine-trithiocyanuric acid (MTCA) aggregates as both the N and S element sources. Noteworthy, MTCA also favored the formation of Ni nanowire via vapor liquid-solid mechanism, while Ni nanoparticles loaded CNFs (Ni/CNFs) was obtained without MTCA. For UOR tests, a high peak current intensity of 37.0 mA mg -1 was obtained on Ni/N,S-CNFs at 0.42 V (vs. SCE), 2-times higher of that on Ni/CNFs. Besides, the catalytic stability of Ni/N,S-CNFs was also improved. The enhanced catalytic properties of Ni/N,S-CNFs for UOR were ascribed to its unique Ni nanowires structure as well as the N, S dual-doping. Our work reveals that the property improvement of metal-based catalysts could be achieved by the heteroatom doping to fine the metal nanostructure. Copyright © 2018. Published by Elsevier Inc.

Radical chemistry at a rural site (Wangdu) in the North China Plain: observation and model calculations of OH, HO2 and RO2 radicals

NASA Astrophysics Data System (ADS)

Tan, Zhaofeng; Fuchs, Hendrik; Lu, Keding; Hofzumahaus, Andreas; Bohn, Birger; Broch, Sebastian; Dong, Huabin; Gomm, Sebastian; Häseler, Rolf; He, Lingyan; Holland, Frank; Li, Xin; Liu, Ying; Lu, Sihua; Rohrer, Franz; Shao, Min; Wang, Baolin; Wang, Ming; Wu, Yusheng; Zeng, Limin; Zhang, Yinsong; Wahner, Andreas; Zhang, Yuanhang

2017-01-01

A comprehensive field campaign was carried out in summer 2014 in Wangdu, located in the North China Plain. A month of continuous OH, HO2 and RO2 measurements was achieved. Observations of radicals by the laser-induced fluorescence (LIF) technique revealed daily maximum concentrations between (5-15) × 106 cm-3, (3-14) × 108 cm-3 and (3-15) × 108 cm-3 for OH, HO2 and RO2, respectively. Measured OH reactivities (inverse OH lifetime) were 10 to 20 s-1 during daytime. The chemical box model RACM 2, including the Leuven isoprene mechanism (LIM), was used to interpret the observed radical concentrations. As in previous field campaigns in China, modeled and measured OH concentrations agree for NO mixing ratios higher than 1 ppbv, but systematic discrepancies are observed in the afternoon for NO mixing ratios of less than 300 pptv (the model-measurement ratio is between 1.4 and 2 in this case). If additional OH recycling equivalent to 100 pptv NO is assumed, the model is capable of reproducing the observed OH, HO2 and RO2 concentrations for conditions of high volatile organic compound (VOC) and low NOx concentrations. For HO2, good agreement is found between modeled and observed concentrations during day and night. In the case of RO2, the agreement between model calculations and measurements is good in the late afternoon when NO concentrations are below 0.3 ppbv. A significant model underprediction of RO2 by a factor of 3 to 5 is found in the morning at NO concentrations higher than 1 ppbv, which can be explained by a missing RO2 source of 2 ppbv h-1. As a consequence, the model underpredicts the photochemical net ozone production by 20 ppbv per day, which is a significant portion of the daily integrated ozone production (110 ppbv) derived from the measured HO2 and RO2. The additional RO2 production from the photolysis of ClNO2 and missing reactivity can explain about 10 % and 20 % of the discrepancy, respectively. The underprediction of the photochemical ozone production at high NOx found in this study is consistent with the results from other field campaigns in urban environments, which underlines the need for better understanding of the peroxy radical chemistry for high NOx conditions.

Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

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

Kim, S.; Kim, S. -Y.; Lee, M.

Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Guangzhou, and Beijing are surrounded by densely forested areas, and recent research has consistently demonstrated the importance of biogenic volatile organic compounds (VOCs) from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical, undermine our ability to assess regional photochemical air pollution problems. We present an observational data set of CO, NO x, SO 2,more » ozone, HONO, and VOCs (anthropogenic and biogenic) from Taehwa research forest (TRF) near the Seoul metropolitan area in early June 2012. The data show that TRF is influenced both by aged pollution and fresh biogenic volatile organic compound emissions. With the data set, we diagnose HO x (OH, HO 2, and RO 2) distributions calculated using the University of Washington chemical box model (UWCM v2.1) with near-explicit VOC oxidation mechanisms from MCM v3.2 (Master Chemical Mechanism). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that (1) different model simulation scenarios cause systematic differences in HO x distributions, especially OH levels (up to 2.5 times), and (2) radical destruction (HO 2 + HO 2 or HO 2 + RO 2) could be more efficient than radical recycling (RO 2 + NO), especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone–VOC–NO x sensitivity and VOC oxidation product formation rates. Overall, the NO x limited regime is assessed except for the morning hours (8 a.m. to 12 p.m. local standard time), but the degree of sensitivity can significantly vary depending on the model scenarios. The model results also suggest that RO 2 levels are positively correlated with oxygenated VOCs (OVOCs) production that is not routinely constrained by observations. These unconstrained OVOCs can cause higher-than-expected OH loss rates (missing OH reactivity) and secondary organic aerosol formation. The series of modeling experiments constrained by observations strongly urge observational constraint of the radical pool to enable precise understanding of regional photochemical pollution problems in the East Asian megacity region.« less

Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

DOE PAGES

Kim, S.; Kim, S. -Y.; Lee, M.; ...

2015-04-29

Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Guangzhou, and Beijing are surrounded by densely forested areas, and recent research has consistently demonstrated the importance of biogenic volatile organic compounds (VOCs) from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical, undermine our ability to assess regional photochemical air pollution problems. We present an observational data set of CO, NO x, SO 2,more » ozone, HONO, and VOCs (anthropogenic and biogenic) from Taehwa research forest (TRF) near the Seoul metropolitan area in early June 2012. The data show that TRF is influenced both by aged pollution and fresh biogenic volatile organic compound emissions. With the data set, we diagnose HO x (OH, HO 2, and RO 2) distributions calculated using the University of Washington chemical box model (UWCM v2.1) with near-explicit VOC oxidation mechanisms from MCM v3.2 (Master Chemical Mechanism). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that (1) different model simulation scenarios cause systematic differences in HO x distributions, especially OH levels (up to 2.5 times), and (2) radical destruction (HO 2 + HO 2 or HO 2 + RO 2) could be more efficient than radical recycling (RO 2 + NO), especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone–VOC–NO x sensitivity and VOC oxidation product formation rates. Overall, the NO x limited regime is assessed except for the morning hours (8 a.m. to 12 p.m. local standard time), but the degree of sensitivity can significantly vary depending on the model scenarios. The model results also suggest that RO 2 levels are positively correlated with oxygenated VOCs (OVOCs) production that is not routinely constrained by observations. These unconstrained OVOCs can cause higher-than-expected OH loss rates (missing OH reactivity) and secondary organic aerosol formation. The series of modeling experiments constrained by observations strongly urge observational constraint of the radical pool to enable precise understanding of regional photochemical pollution problems in the East Asian megacity region.« less

EGR-1 regulates Ho-1 expression induced by cigarette smoke

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

Chen, Huaqun, E-mail: chenhuaqun@njnu.edu.cn; Wang, Lijuan; Gong, Tao

2010-05-28

As an anti-oxidant molecule, heme oxygenase-1 (HO-1) has been implicated in the protection of lung injury by cigarette smoke (CS). The mechanisms regulating its expression have not been defined. In this report, the role of early growth response 1 (EGR-1) in the regulation of Ho-1 expression was investigated. In C57BL/6 mice with CS exposure, HO-1 was greatly increased in bronchial epithelial cells and alveolar inflammatory cells. In primary cultured mouse lung fibroblasts and RAW264.7 cells exposed to cigarette smoke water extract (CSE), an increase in HO-1 protein level was detected. In addition, CSE induced HO-1 expression was decreased in Egr-1more » deficient mouse embryo fibroblasts (Egr-1{sup -/-} MEFs). Nuclear localization of EGR-1 was examined in mouse lung fibroblasts after exposure to CSE. Luciferase reporter activity assays showed that the enhancer region of the Ho-1 gene containing a proposed EGR-1 binding site was responsible for the induction of HO-1. A higher increase of alveolar mean linear intercept (Lm) was observed in lung tissues, and a larger increase in the number of total cells and monocytes/macrophages from bronchial alveolar lavage fluid was found in CS-exposed mice by loss of function of EGR-1 treatment. In summary, the present data demonstrate that EGR-1 plays a critical role in HO-1 production induced by CS.« less

Management of oxidative stress by heme oxygenase-1 in cisplatin-induced toxicity in renal tubular cells.

PubMed

Schaaf, G J; Maas, R F M; de Groene, E M; Fink-Gremmels, J

2002-08-01

Induction of heme oxygenase-1 (HO-1) may serve as an immediate protective response during treatment with the cytostatic drug cisplatin (CDDP). Oxidative pathways participate in the characteristic nephrotoxicity of CDDP. In the present study, cultured tubular cells (LLC-PK1) were used to investigate whether induction of HO provided protection against CDDP by maintaining the cellular redox balance. The antioxidants, alpha-tocopherol (TOCO) and N-acetylcysteine (NAC), were used to demonstrate that elevation of ROS levels contribute to the development of CDDP-induced cytotoxicity. Chemical modulators of HO activity were used to investigate the role of HO herein. Hemin was used to specifically induce HO-1, while exposure of the cells to tin-protoporphyrin (SnPP) was shown to inhibit HO activity. Hemin treatment prior to CDDP-exposure significantly decreased the generation of ROS to control levels, while inhibition of HO increased the ROS levels beyond the levels measured in cells treated with CDDP alone. Furthermore, HO induction protected significantly against the cytotoxicity of CDDP, although this protection was limited. Similar results were obtained when the cells were preincubated with TOCO, suggesting that mechanisms other than impairment of the redox ratio are important in CDDP-induced loss of cell viability in vitro. In addition, SnPP treatment exacerbated the oxidative response and cytotoxicity of CDDP, especially at low CDDP concentrations. We therefore conclude that HO is able to directly limit the CDDP-induced oxidative stress response and thus serves as safeguard of the cellular redox balance.

Holmium laser lithotripsy (HoLL) of ureteral calculi

NASA Astrophysics Data System (ADS)

Kuntz, Rainer M.; Lehrich, Karin; Fayad, Amr

2001-05-01

The effectiveness and side effects of ureteroscopic HoLL of ureteral stones should be evaluated. In 63 patients (17 female, 46 males) a total of 75 stones of 3-20 mm diameter were treated with ureteroscopic HoLL. 18.7 percent of stones were located in the proximal third, 24.0 percent in the middle third and 57.3 percent in the distal third of the ureter. HoLL was performed with small diameter semirigid and flexible ureteroscopes, 220 or 365 nm flexible laser fibers and a holmium:YAG laser at a power of 5-15 W (0.5-1.0 J, 10- 15 Hz). 47 of 63 patients (74.6 percent) were immediately free of stones, and 8 others (12.6 percent) lost their residual fragments spontaneously within two weeks. Another 2 patients received additional chmolitholysis for uric acid stone fragments, i.e. 90.5 percent of patients were stone free by one sitting of ureterscopic HoLL. Of the remaining 6 patients (9.5 percent) who still had residual calculi 4 weeks after HoLL, 2 asymptomatic patients refused any additional treatment, 2 patients preferred treatment with ESWL, and 2 patients had a successful second HoLL, thereby raising the success rate of ureteroscopic HoLL to 93.7 percent. 2 patients showed contrast medium extravasation on retrograde ureterograms, due to guide wire perforation. No ureteral stricture occurred. In conclusion, transurethral ureteroscopic HoLL proved to be a safe and successful minimal invasive treatment of ureteral calculi.

Source discrimination of heavy metals in sediment and water of To Lich River in Hanoi City using multivariate statistical approaches.

PubMed

Thuong, Nguyen Thi; Yoneda, Minoru; Ikegami, Maiko; Takakura, Masato

2013-10-01

The concentrations of Mn, Fe, Ni, Cr, Cu, Pb, Zn, As, and Cd were determined to evaluate the level of contamination of To Lich River in Hanoi City. All metal concentrations in 0-10-cm water samples, except Mn, were lower than the maximum permitted concentration for irrigation water standard. Meanwhile, concentrations of As, Cd, and Zn in 0-30-cm sediments were likely to have adverse effects on agriculture and aquatic life. Sediment pollution assessment was undertaken using enrichment factor and geoaccumulation index (I geo). The I geo results indicated that the sediment was not polluted with Cr, Mn, Fe, and Ni, and the pollution level increased in the order of Cu < Pb < Zn < As < Cd. Meanwhile, significant enrichment was shown for Cd, As, Zn, and Pb. Cluster and principal component analyses suggest that As and Mn in sediment were derived from both lithogenic and anthropogenic sources, while Cu, Pb, Zn, Cr, Cd, and Ni originated from anthropogenic sources such as vehicular fumes for Pb and metallic discharge from industrial sources and fertilizer application for other metals.

Effect of oxygen plasma treatment on crystal growth mode at pentacene/Ni interface in organic thin-film transistors.

PubMed

Song, Bang Joo; Hong, Kihyon; Kim, Woong-Kwon; Kim, Kisoo; Kim, Sungjun; Lee, Jong-Lam

2010-11-25

We report how treatment of nickel (Ni) with O(2) plasma affects the polarity of Ni surface, crystallinity of pentacene film on the Ni, and electrical properties of pentacene organic thin-film transistors (OTFTs) that use Ni as source-drain electrodes. The polar component of surface energy in Ni surface increased from 8.1 to 43.3 mJ/m(2) after O(2)-plasma treatment for 10 s. From X-ray photoelectron spectra and secondary electron emission spectra, we found that NiO(x) was formed on the O(2)-plasma-treated Ni surface and the work function of O(2)-plasma-treated Ni was 0.85 eV higher than that of untreated Ni. X-ray diffraction and atomic force microscopy measurements showed that pentacene molecules are well aligned as a thin-film and grains grow much larger on O(2)-plasma-treated Ni than on untreated Ni. This change in the growth mode is attributed to the reduction of interaction energy between pentacene and Ni due to formation of oxide at the Ni/pentacene interface. Thus, O(2)-plasma treatment promoted the growth of well-ordered pentacene film and lowered both the hole injection barrier and the contact resistance between Ni and pentacene by forming NiO(x), enhancing the electrical property of bottom-contact OTFTs.

Hydroxylated and methyl sulfone PCB metabolites in adipose and whole blood of polar bear (Ursus maritimus) from East Greenland.

PubMed

Sandala, G M; Sonne-Hansen, C; Dietz, R; Muir, D C G; Valters, K; Bennett, E R; Born, E W; Letcher, R J

2004-09-20

Persistent methyl sulfone (MeSO2-) and hydroxylated (HO-) polychlorinated biphenyl (PCB) metabolites have emerged as important classes of environmental contaminants in vertebrate, aquatic biota and humans. In the present study, PCB, MeSO2-PCB and HO-PCB concentrations and congener patterns were determined in the whole blood and adipose tissue of male (n = 7) and female (n = 12) polar bears (Ursus maritimus) of random age (3-25 years of age), and collected in 1999-2001 from the Ittoqqortoormiit/Scoresby Sound area in central East Greenland. There was no significant difference (P < 0.05) between males and females with respect to PCB or PCB metabolite concentrations in either tissue. The mean sum (Sigma) PCB concentrations were 7020+/-3366 ng/g lipid weight (lw) (range 2708-18148 ng/g lw) and 46.1+/-44.6 ng/g wet weight (ww) (range 12.6-204.2 ng/g ww) in adipose and blood, respectively. The mean Sigma-HO-PCB concentration in whole blood was 182.3+/-72.1 ng/g ww (range 93.8-382.1 ng/g ww). The mean Sigma-HO-PCB to Sigma-PCB concentration ratios in whole blood were 4.59+/-3.58 (range 1.03-11.88) and 8.30+/-5.56 (range 2.16-19.47) in females and males, respectively, which are the highest ratios reported so far for polar bears from any population, or for any free-ranging animal. Sigma-HO-PCB concentrations were greater than all other major classes of organochlorines (i.e. Sigma-PCBs, Sigma-MeSO2-PCBs, Sigma-chlordanes (CHLs), Sigma-hexachlorocyclohexanes (HCHs) and Sigma-chlorobenzenes (CBzs). The mean Sigma-MeSO2-PCB concentrations were 699+/-836 ng/g lw (range 127-3920 ng/g lw) and 10.9+/-9.6 ng/g ww (range 4.3-52.1 ng/g ww) in the adipose and blood, respectively. Regardless of age and sex, in both adipose and whole blood the MeSO2-PCB congener pattern was dominated by 3'- and 4'-MeSO2-CB101 and -CB87, and 4-MeSO2-CB149 (approx. 70% of the Sigma-MeSO2-PCBs). Minor differences in the MeSO2-PCB congener pattern were observed between blood and adipose, which suggests the possible influence of metabolite structure on mobilization and/or deposition to the adipose tissue. Sixteen HO-PCB congeners and one di-HO-PCB congener were identified, and five HO-PCB isomers and one di-HO-PCB isomer were detected. However, congener patterns were dominated by 4'-OH-CB120, 4-HO-CB146/3-HO-CB153, 4-OH-CB187, 4'-HO-CB172, 4-HO-CB193 and 4,4'-di-HO-CB202 (> 10 ng/g ww). HO-PCB congener patterns in whole blood were not significantly different (P < 0.05) between males and females. Other chlorinated phenolic contaminants, pentachlorophenol (0.3+/-0.3 ng/g ww) and 4-HO-heptachlorostyrene (7.5+/-2.9 ng/g ww) were also detected in blood. To our knowledge, this is to first report comparing PCBs, MeSO2-PCBs and HO-PCBs in whole blood and adipose tissue in a free-ranging wildlife species. HO-PCBs and MeSO2-PCBs are both important circulating contaminants in polar bears from this eastern Greenland population. Given the known toxicities of PCB metabolites, this population of polar bear may be experiencing health risks due to exposure to a complex loading of organohalogen contaminants that include HO-PCB and MeSO2-PCB metabolites.

Effects of Remote Ischemic Preconditioning on Heme Oxygenase-1 Expression and Cutaneous Wound Repair

PubMed Central

Cremers, Niels A. J.; Wever, Kimberley E.; Wong, Ronald J.; van Rheden, René E. M.; Vermeij, Eline A.; van Dam, Gooitzen M.; Carels, Carine E.; Lundvig, Ditte M. S.; Wagener, Frank A. D. T. G.

2017-01-01

Skin wounds may lead to scar formation and impaired functionality. Remote ischemic preconditioning (RIPC) can induce the anti-inflammatory enzyme heme oxygenase-1 (HO-1) and protect against tissue injury. We aim to improve cutaneous wound repair by RIPC treatment via induction of HO-1. RIPC was applied to HO-1-luc transgenic mice and HO-1 promoter activity and mRNA expression in skin and several other organs were determined in real-time. In parallel, RIPC was applied directly or 24h prior to excisional wounding in mice to investigate the early and late protective effects of RIPC on cutaneous wound repair, respectively. HO-1 promoter activity was significantly induced on the dorsal side and locally in the kidneys following RIPC treatment. Next, we investigated the origin of this RIPC-induced HO-1 promoter activity and demonstrated increased mRNA in the ligated muscle, heart and kidneys, but not in the skin. RIPC did not change HO-1 mRNA and protein levels in the wound 7 days after cutaneous injury. Both early and late RIPC did not accelerate wound closure nor affect collagen deposition. RIPC induces HO-1 expression in several organs, but not the skin, and did not improve excisional wound repair, suggesting that the skin is insensitive to RIPC-mediated protection. PMID:28218659

Nervous system disruption and concomitant behavioral abnormality in early hatched pufferfish larvae exposed to heavy oil.

PubMed

Kawaguchi, Masahumi; Sugahara, Yuki; Watanabe, Tomoe; Irie, Kouta; Ishida, Minoru; Kurokawa, Daisuke; Kitamura, Shin-Ichi; Takata, Hiromi; Handoh, Itsuki C; Nakayama, Kei; Murakami, Yasunori

2011-08-01

Spills of heavy oil (HO) over the oceans have been proven to have an adverse effect on marine life. It has been hypothesized that exposure of early larvae of sinking eggs to HO leads largely to normal morphology, whereas abnormal organization of the developing neural scaffold is likely to be found. HO-induced disruption of the nervous system, which controls animal behavior, may in turn cause abnormalities in the swimming behavior of hatched larvae. To clarify the toxicological effects of HO, we performed exposure experiments and morphological and behavioral analyses in pufferfish (Takifugu rubripes) larvae. Fertilized eggs of pufferfish were exposed to 50 mg/L of HO for 8 days and transferred to fresh seawater before hatching. The hatched larvae were observed for their swimming behavior, morphological appearance, and construction of muscles and nervous system. In HO-exposed larvae, we did not detect any anomaly of body morphology. However, they showed an abnormal swimming pattern and disorganized midbrain, a higher center controlling movement. Our results suggest that HO-exposed fishes suffer developmental disorder of the brain that triggers an abnormal swimming behavior and that HO may be selectively toxic to the brain and cause physical disability throughout the life span of these fishes.

Heme oxygenase-1 regulates mitochondrial quality control in the heart

PubMed Central

Hull, Travis D.; Boddu, Ravindra; Guo, Lingling; Tisher, Cornelia C.; Traylor, Amie M.; Patel, Bindiya; Joseph, Reny; Prabhu, Sumanth D.; Suliman, Hagir B.; Piantadosi, Claude A.; George, James F.

2016-01-01

The cardioprotective inducible enzyme heme oxygenase-1 (HO-1) degrades prooxidant heme into equimolar quantities of carbon monoxide, biliverdin, and iron. We hypothesized that HO-1 mediates cardiac protection, at least in part, by regulating mitochondrial quality control. We treated WT and HO-1 transgenic mice with the known mitochondrial toxin, doxorubicin (DOX). Relative to WT mice, mice globally overexpressing human HO-1 were protected from DOX-induced dilated cardiomyopathy, cardiac cytoarchitectural derangement, and infiltration of CD11b+ mononuclear phagocytes. Cardiac-specific overexpression of HO-1 ameliorated DOX-mediated dilation of the sarcoplasmic reticulum as well as mitochondrial disorganization in the form of mitochondrial fragmentation and increased numbers of damaged mitochondria in autophagic vacuoles. HO-1 overexpression promotes mitochondrial biogenesis by upregulating protein expression of NRF1, PGC1α, and TFAM, which was inhibited in WT animals treated with DOX. Concomitantly, HO-1 overexpression inhibited the upregulation of the mitochondrial fission mediator Fis1 and resulted in increased expression of the fusion mediators, Mfn1 and Mfn2. It also prevented dynamic changes in the levels of key mediators of the mitophagy pathway, PINK1 and parkin. Therefore, these findings suggest that HO-1 has a novel role in protecting the heart from oxidative injury by regulating mitochondrial quality control. PMID:27110594

Low temperature specific heat of frustrated antiferromagnet HoInCu4

NASA Astrophysics Data System (ADS)

Weickert, Franziska; Fritsch, Veronika; Bambaugh, Ryan; Sarrao, John; Thompson, Joe D.; Movshovich, Roman

2014-03-01

We present low temperature specific heat measurements of single crystal HoInCu4, down to 35 mK and in magnetic field up to 12 Tesla. Ho atoms are arranged in an FCC lattice of the edge-sharing tetrahedra, and undergo an antiferromagnetic ordering at TN = 0.76 K, with the frustration parameter f = -ΘCW /TN of 14.3. Magnetic AF order is suppressed in field H0 ~ 4 T. The low temperature Schottky anomaly due to Ho evolves smoothly as a function of field through H0 and TN. The peak value of the anomaly remains roughly constant from 0 T to 12 T. The temperature of the anomaly's peak remains constant at TSch ~ 170 mK for H

Suspected hypertrophic osteopathy in an ancient canid: Differential diagnosis of possible etiologies.

PubMed

Lawler, Dennis F; Reetz, Jennifer A; Sackman, Jill E; Evans, Richard H; Widga, Christopher

2015-06-01

Hypertrophic osteopathy (HO) has been reported in numerous mammalian species, but no reports address the range of conditions that can lead to HO, or the implications of those conditions, for archaeological diagnosis. We describe suspected HO from skeletal remains of an ancient large domestic dog recovered in Iowa, USA, at the Cherokee Sewer site. Canid remains from this site date 7430-7020calBP. The site is believed to have been a temporary, low-intensity campsite where bison were procured. Over 100 specimens from two small dogs, two large dogs, and a coyote, are present in the archaeofaunal assemblage. We document five pathological metapodials; an affected left ulna, radius, tuber calcaneus, accessory carpal, radial carpal; and an affected right central, second, and third tarsal within in a proliferative mass. HO was suspected based on gross morphology, radiography, and computed tomography. HO is a paraneoplastic syndrome with undetermined underlying pathogenesis; neuroendocrine complication of a number of neoplastic and non-neoplastic diseases is suspected. We review known disease associations of HO to provide a balanced field for considering differential diagnosis of suspect archaeological specimens, and suggest that definitive diagnosis of HO, or suspected HO, may be impossible in many instances where only skeletal remains are available for study. Copyright © 2015 Elsevier Inc. All rights reserved.

Tuning into single-band red upconversion luminescence in Yb(3+)/Ho(3+) activated nano-glass-ceramics through Ce(3+) doping.

PubMed

Chen, Daqin; Zhou, Yang; Wan, Zhongyi; Ji, Zhenguo; Huang, Ping

2015-03-28

Yb(3+)/Ho(3+) activated glass ceramics containing β-YF3 nanocrystals were successfully fabricated. The green ((5)S2/(5)F4→(5)I8) upconversion emission is dominant in the glass ceramics and is about 160 times stronger than that of the precursor glass, resulting from the partition of lanthanide activators into a low-phonon-energy crystalline lattice and the subsequent low probability of multi-phonon nonradiative relaxation from the (5)S2/(5)F4 and (5)I6 states to the lower ones. Upon the introduction of Ce(3+) ions into nano-glass-ceramics, two efficient cross-relaxation processes between Ho(3+) and Ce(3+), i.e., Ho(3+):(5)S2/(5)F4 + Ce(3+):(2)F5/2→Ho(3+):(5)F5 + Ce(3+):(2)F7/2 and Ho(3+):(5)I6 + Ce(3+):(2)F5/2→Ho(3+):(5)I7 + Ce(3+):(2)F7/2, are demonstrated to greatly suppress the population of the green-emitting (5)S2/(5)F4 state and to enhance the population of the red-emitting (5)F5 one, leading to the intense single-band red UC radiation of Ho(3+).

Production of GMP-grade radioactive holmium loaded poly(L-lactic acid) microspheres for clinical application.

PubMed

Zielhuis, S W; Nijsen, J F W; de Roos, R; Krijger, G C; van Rijk, P P; Hennink, W E; van het Schip, A D

2006-03-27

Radioactive holmium-166 loaded poly(L-lactic acid) microspheres are promising systems for the treatment of liver malignancies. The microspheres are loaded with holmium acetylacetonate (HoAcAc) and prepared by a solvent evaporation method. After preparation, the microspheres (Ho-PLLA-MS) are activated by neutron irradiation in a nuclear reactor. In this paper, the aspects of the production of a (relatively) large-scale GMP batch (4 g, suitable for treatment of 5-10 patients) of Ho-PLLA-MS are described. The critical steps of the Ho-PLLA-MS production process (sieving procedure, temperature control during evaporation and raw materials) were considered and the pharmaceutical quality of the microspheres was evaluated. The pharmaceutical characteristics (residual solvents, possible bacterial contaminations and endotoxins) of the produced Ho-PLLA-MS batches were in compliance with the requirements of the European Pharmacopoeia. Moreover, neutron irradiated Ho-PLLA-MS retained their morphological integrity and the holmium remained stably associated with the microspheres; it was observed that after 270h (10 times the half-life of Ho-166) only 0.3+/-0.1% of the loading was released from the microspheres in an aqueous solution. In conclusion, Ho-PLLA-MS which are produced as described in this paper, can be clinically applied, with respect to their pharmaceutical quality.

Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted 163Ho ions

NASA Astrophysics Data System (ADS)

Gastaldo, L.; Ranitzsch, P. C.-O.; von Seggern, F.; Porst, J.-P.; Schäfer, S.; Pies, C.; Kempf, S.; Wolf, T.; Fleischmann, A.; Enss, C.; Herlert, A.; Johnston, K.

2013-05-01

For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of 163Ho using MMCs having the radioactive 163Ho ions implanted in the absorber. The isotope 163Ho decays through electron capture to 163Dy and features the smallest known QEC value. This peculiarity makes 163Ho a very interesting candidate to investigate the value of the electron neutrino mass by the analysis of the energy spectrum. The implantation of 163Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. Moreover the performance of the detector prototype having the 163Ho ions implanted in the absorber is already close to the requirements needed for an experiment with sub-eV sensitivity to the electron neutrino mass. Based on these results, an optimized detector design for future 163Ho experiments is presented.

Heme oxygenase/carbon monoxide signaling pathways: regulation and functional significance.

PubMed

Ryter, Stefan W; Otterbein, Leo E; Morse, Danielle; Choi, Augustine M K

2002-01-01

Carbon monoxide (CO), a gaseous second messenger, arises in biological systems during the oxidative catabolism of heme by the heme oxygenase (HO) enzymes. HO exists as constitutive (HO-2, HO-3) and inducible isoforms (HO-1), the latter which responds to regulation by multiple stress-stimuli. HO-1 confers protection in vitro and in vivo against oxidative cellular stress. Although the redox active compounds that are generated from HO activity (i.e. iron, biliverdin-IXalpha, and bilirubin-IXa) potentially modulate oxidative stress resistance, increasing evidence points to cytoprotective roles for CO. Though not reactive, CO regulates vascular processes such as vessel tone, smooth muscle proliferation, and platelet aggregation, and possibly functions as a neurotransmitter. The latter effects of CO depend on the activation of guanylate cyclase activity by direct binding to the heme moiety of the enzyme, stimulating the production of cyclic 3':5'-guanosine monophosphate. CO potentially interacts with other intracellular hemoprotein targets, though little is known about the functional significance of such interactions. Recent progress indicates that CO exerts novel anti-inflammatory and anti-apoptotic effects dependent on the modulation of the p38 mitogen activated protein kinase (MAPK)-signaling pathway. By virtue of these effects, CO confers protection in oxidative lung injury models, and likely plays a role in HO-1 mediated tissue protection.

Analysis of bone-cartilage-stromal progenitor populations in trauma induced and genetic models of heterotopic ossification

PubMed Central

Agarwal, Shailesh; Loder, Shawn; Li, Shuli; Shrestha, Swati; Li, Jon; Zhao, Bin; Mishina, Yuji; James, Aaron; Levi, Benjamin

2016-01-01

Heterotopic ossification (HO), the formation of extra-skeletal bone in soft tissues, is a pathologic process occurring after substantial burns or trauma, or in patients with type I bone morphogenetic protein (BMP) receptor hyperactivating mutations. Identifying the cells responsible for de novo bone formation during adulthood is of critical importance for therapeutic and regenerative purposes. Using a model of trauma-induced HO with hindlimb Achilles’ tenotomy and dorsal burn injury and a genetic non-trauma HO model (Nfatc1-Cre/caAcvr1fl/wt), we demonstrate enrichment of previously defined bone-cartilage-stromal progenitor cells (BCSP: AlphaV+/CD105+/Tie2-/CD45-/Thy1-/6C3-) at the site of HO formation when compared with marrow isolated from the ipsilateral hindlimb, or from tissue of the contralateral, uninjured hindlimb. Upon transplantation into tenotomy sites soon after injury, BCSPs isolated from neonatal mice or developing HO incorporate into the developing lesion in cartilage and bone and express chondrogenic and osteogenic transcription factors. Additionally, BCSPs isolated from developing HO similarly incorporate into new HO lesions upon transplantation. Finally, adventitial cells, but not pericytes, appear to play a supportive role in HO formation. Our findings indicate that BCSPs contribute to de novo bone formation during adulthood and may hold substantial regenerative potential. PMID:27068890

Towards a realistic 3D simulation of the extraction region in ITER NBI relevant ion source

NASA Astrophysics Data System (ADS)

Mochalskyy, S.; Wünderlich, D.; Fantz, U.; Franzen, P.; Minea, T.

2015-03-01

The development of negative ion (NI) sources for ITER is strongly accompanied by modelling activities. The ONIX code addresses the physics of formation and extraction of negative hydrogen ions at caesiated sources as well as the amount of co-extracted electrons. In order to be closer to the experimental conditions the code has been improved. It includes now the bias potential applied to first grid (plasma grid) of the extraction system, and the presence of Cs+ ions in the plasma. The simulation results show that such aspects play an important role for the formation of an ion-ion plasma in the boundary region by reducing the depth of the negative potential well in vicinity to the plasma grid that limits the extraction of the NIs produced at the Cs covered plasma grid surface. The influence of the initial temperature of the surface produced NI and its emission rate on the NI density in the bulk plasma that in turn affects the beam formation region was analysed. The formation of the plasma meniscus, the boundary between the plasma and the beam, was investigated for the extraction potentials of 5 and 10 kV. At the smaller extraction potential the meniscus moves closer to the plasma grid but as in the case of 10 kV the deepest meniscus bend point is still outside of the aperture. Finally, a plasma containing the same amount of NI and electrons (nH- =ne =1017 m-3) , representing good source conditioning, was simulated. It is shown that at such conditions the extracted NI current can reach values of ˜32 mA cm-2 using ITER-relevant extraction potential of 10 kV and ˜19 mA cm-2 at 5 kV. These results are in good agreement with experimental measurements performed at the small scale ITER prototype source at the test facility BATMAN.

Development of mid-infrared solid state lasers for spaceborne lidar

NASA Technical Reports Server (NTRS)

Whitney, Donald A.; Kim, Kyong H.

1989-01-01

Laser performance of Ho(3+):Tm(3+):Cr(3+):YAG crystals was investigated under both Cr:GSAG laser and flashlamp pumping. A flashlamp pumped Cr:GSAG laser was built to simulate high power quasi-CW laser diode pumping of a 2.1 micrometer holmium laser. The 2.1 micrometer output laser energy exceeded more than 14 mJ, the highest value reported to date under laser pumping near 785 nm. This was obtained in a pulse length of nearly 650 microsec from a 3 x 3 mm Ho:Tm:Cr:YAG rod by using the flashlamp-pumped Cr:CSAG laser as a pumping source at the diode laser wavelength, 785 micrometers. In addition, Ho:Tm:Cr:YAG crystals with various Tm(3+) concentrations were evaluated for flashlamp-pumped normal mode and Q-switched 2.1 micrometer laser operations under a wide variety of experimental conditions in order to understand internal dynamic processes among the ions and to determine an optimum lasing condition. An increase of the laser slope efficiency was observed with the increase of the Tm(3+) concentration from 2.5 to 4.5 atomic percent. The thermal dependence of the laser performance was also investigated. Q-switched laser output energies corresponding to nearly 100 percent of the normal-mode laser energies were obtained in a strong single spike of 200 ns pulse length by optimizing the opening time of a lithium niobate Q-switch.

Observation of galactic cosmic ray spallation events from the SoHO mission 20-yr operation of LASCO

NASA Astrophysics Data System (ADS)

Koutchmy, S.; Tavabi, E.; Urtado, O.

2018-07-01

A shower of secondary cosmic ray (CR) particles is produced at high altitudes in the Earth's atmosphere, so the primordial galactic cosmic rays (GCRs) are never directly measured outside the Earth magnetosphere and atmosphere. They approach the Earth and other planets in the complex pattern of rigidity's dependence, generally excluded by the magnetosphere. GCRs revealed by images of single nuclear reactions also called spallation events are described here. Such an event was seen on 2015 November 29 using a unique Large Angle and Spectrometric Coronagraphs C3 space coronagraph routine image taken during the Solar and Heliospheric Observatory (SoHO) mission observing uninterruptedly at the Lagrangian L1 point. The spallation signature of a GCR identified well outside the Earth's magnetosphere is obtained for the first time. The resulting image includes different diverging linear `tracks' of varying intensity, leading to a single pixel; this frame identifies the site on the silicon CCD chip of the coronagraph camera. There was no solar flare reported at that time, nor coronal mass ejection and no evidence of optical debris around the spacecraft. More examples of smaller CR events have been discovered through the 20 yr of continuous observations from SoHO. This is the first spallation event from a CR, recorded outside the Earth's magnetosphere. We evaluate the probable energy of these events suggesting a plausible galactic source.

Oligomerization reactions for precursors to secondary organic aerosol: Comparison between two formation mechanisms for the oligomeric hydroxyalkyl hydroperoxides

NASA Astrophysics Data System (ADS)

Zhao, Qiangli; Wang, Weina; Liu, Fengyi; Lü, Jian; Wang, Wenliang

2017-10-01

To better understand the formation mechanism of oligomeric hydroxyalkyl hydroperoxides HOROO(SCI)nH composed of stabilized Criegee intermediate (SCI) as a chain unit, the reactions of SCI with hydroxyalkyl hydroperoxides (HOROOH) and hydroxyalkylperoxy radical (HORO2) as well as HO2 radical were investigated. For the reactions of HORO2 + SCI, two preferred pathways involving a SCI insertion in HOROOH hydroperoxide bond can be found, and the formation of HOROO(SCI)H is the dominant pathway in the reaction of HOCH2(CH3)2COOH + (CH3)2COO. The structures of the HORO2, HOROOH as well as the SCIs play a crucial role in determining the reactivity of the oligomerization. Both the reactions of HORO2 + SCI + HO2 and HOROOH + SCI could be the source of the processors to the formation of secondary organic aerosol (SOA). But from the point of free energy barriers, the formation of HOROO(SCI)H prefers to follow the mechanism involving initiation by the reaction of a HORO2 and a SCI, sequential addition of SCIs, and termination by reaction with the HO2 radical. The rate coefficients show negative temperature dependence and vary in different systems depending on the reactants. The reaction process and constituents of the products can be regulated by temperature and reactants.

Observation of galactic cosmic ray spallation events from the SoHO mission 20-Year operation of LASCO

NASA Astrophysics Data System (ADS)

Koutchmy, S.; Tavabi, E.; Urtado, O.

2018-05-01

A shower of secondary Cosmic Ray (CR) particles is produced at high altitudes in the Earth's atmosphere, so the primordial Galactic Cosmic Rays (GCRs) are never directly measured outside the Earth magnetosphere and atmosphere. They approach the Earth and other planets in the complex pattern of rigidity's dependence, generally excluded by the magnetosphere. GCRs revealed by images of single nuclear reactions also called spallation events are described here. Such an event was seen on Nov. 29, 2015 using a unique LASCO C3 space coronagraph routine image taken during the Solar and Heliospheric Observatory (SoHO) mission observing uninterruptedly at the Lagrangian L1 point. The spallation signature of a GCR identified well outside the Earth's magnetosphere is obtained for the 1st time. The resulting image includes different diverging linear "tracks" of varying intensity, leading to a single pixel; this frame identifies the site on the silicon CCD chip of the coronagraph camera. There was no solar flare reported at that time, nor Coronal Mass Ejection (CME) and no evidence of optical debris around the spacecraft. More examples of smaller CR events have been discovered through the 20 years of continuous observations from SoHO. This is the first spallation event from a CR, recorded outside the Earth's magnetosphere. We evaluate the probable energy of these events suggesting a plausible galactic source.

Follow-up of serious offender patients in the community: multiple methods of tracing.

PubMed

Jamieson, Elizabeth; Taylor, Pamela J

2002-01-01

Longitudinal studies of people with mental disorder are important in understanding outcome and intervention effects but attrition rates can be high. This study aimed to evaluate use of multiple record sources to trace, over 12 years, a one-year discharge cohort of high-security hospital patients. Everyone leaving such a hospital in 1984 was traced until a census date of 31 December 1995. Data were collected from several national databases (Office for National Statistics (ONS), Home Office (HO) Offenders' Index, Police National Computer Records, the Electoral Roll) and by hand-searching responsible agency records (HO, National Health Service). Using all methods, only three of the 204 patients had no follow-up information. Home Office Mental Health Unit data were an excellent source, but only for people still under discharge restrictions (<50% after eight years). Sequential tracing of hospital placements for people never or no longer under such restrictions was laborious and also produced only group-specific yield. The best indicator of community residence was ONS information on general practitioner (GP/primary care) registration. The electoral roll was useful when other sources were exhausted. Follow-up of offenders/offender-patients has generally focused on event data, such as re-offending. People untraced by that method alone, however, are unlikely to be lost to follow-up on casting a wider records net. Using multiple records, attrition at the census was 38%, but, after certain assumptions, reduced further to 5%.

Quantifying sources of bias in National Healthcare Safety Network laboratory-identified Clostridium difficile infection rates.

PubMed

Haley, Valerie B; DiRienzo, A Gregory; Lutterloh, Emily C; Stricof, Rachel L

2014-01-01

To assess the effect of multiple sources of bias on state- and hospital-specific National Healthcare Safety Network (NHSN) laboratory-identified Clostridium difficile infection (CDI) rates. Sensitivity analysis. A total of 124 New York hospitals in 2010. New York NHSN CDI events from audited hospitals were matched to New York hospital discharge billing records to obtain additional information on patient age, length of stay, and previous hospital discharges. "Corrected" hospital-onset (HO) CDI rates were calculated after (1) correcting inaccurate case reporting found during audits, (2) incorporating knowledge of laboratory results from outside hospitals, (3) excluding days when patients were not at risk from the denominator of the rates, and (4) adjusting for patient age. Data sets were simulated with each of these sources of bias reintroduced individually and combined. The simulated rates were compared with the corrected rates. Performance (ie, better, worse, or average compared with the state average) was categorized, and misclassification compared with the corrected data set was measured. Counting days patients were not at risk in the denominator reduced the state HO rate by 45% and resulted in 8% misclassification. Age adjustment and reporting errors also shifted rates (7% and 6% misclassification, respectively). Changing the NHSN protocol to require reporting of age-stratified patient-days and adjusting for patient-days at risk would improve comparability of rates across hospitals. Further research is needed to validate the risk-adjustment model before these data should be used as hospital performance measures.

HO:LULF and HO:LULF Laser Materials

NASA Technical Reports Server (NTRS)

Barnes, Norman P. (Inventor); Morrison, Clyde A. (Inventor); Filer, Elizabeth D. (Inventor); Jani, Mahendra G. (Inventor); Murray, Keith E. (Inventor); Lockard, George E. (Inventor)

1998-01-01

A laser host material LULF (LuLiF4) is doped with holmium (Ho) and thulium (Tm) to produce a new laser material that is capable of laser light production in the vicinity of 2 microns. The material provides an advantage in efficiency over conventional Ho lasers because the LULF host material allows for decreased threshold and upconversion over such hosts as YAG and YLF. The addition of Tm allows for pumping by commonly available GaAlAs laser diodes. For use with flashlamp pumping, erbium (Er) may be added as an additional dopant. For further upconversion reduction, the Tm can be eliminated and the Ho can be directly pumped.

75 FR 52534 - Su Van Ho: Debarment Order

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-26

... Salmonella bacteria, with verification of such exportation or destruction by FDA. Mr. Ho concealed and... with Salmonella bacteria. As a result of his conviction, on June 10, 2010, FDA sent Mr. Ho a notice by...

Impacts of doping concentration on the saturable characteristics of Tm-Ho codoped fiber saturable absorber

NASA Astrophysics Data System (ADS)

Tao, Mengmeng; Feng, Guobin; Yu, Ting; Ye, Xisheng; Wang, Zhenbao; Shen, Yanlong; Zhao, Jun

2018-03-01

Impacts of Tm ion concentration and Ho ion concentration on the saturable behaviors of Tm-Ho codoped fiber saturable absorbers and the output characteristics of the passively Q-switched laser systems are investigated and analyzed both at the initial lasing state and the stable passive Q-switching state. Simulations show that, varying concentrations of Tm and Ho ions have different impacts on the temporal evolution processes but similar effects on the macroscopic characteristics of the laser system. The root for the impacts of dopant concentrations is the population of the 3H6 energy level and the cavity loss it induces. For Tm ions, the rise of the Tm concentration improves the population of the 3H6 energy level directly, while, for Ho ions, higher Ho concentration leads to larger recovery rate of the 3H6 energy level, thus increasing the population of the 3H6 energy level indirectly. As for limited total dopant concentration, the Tm:Ho concentration ratio can be optimized for different applications.

FAGE measurements of tropospheric HO with measurements and model of interferences

NASA Technical Reports Server (NTRS)

Hard, T. M.; Mehrabzadeh, A. A.; Chan, C. Y.; O'Brien, R. J.

1992-01-01

Ambient HO measurements by low-pressure laser-excited fluorescence with chemical modulation, and supporting ozone and water-vapor data, are presented for periods in May and August 1987. The observed peak daytime ambient HO concentrations are in the range (2.5 to 8) x 10 exp 6 molecules/cu cm and show small negative offsets due to photochemical interference. Direct measurements of the interference at fixed (O3) give the dependence on ambient (H2O) and on the modulating reagent (isobutane). At ambient (O3) = 30 ppb and 10 torr H2O, with excitation and detection at a total pressure of 4 torr, the net interference is equal to (HO) = -1.3 x 10 exp 6 molecules/cu cm. Production of HO by the reaction of isobutane with O(1D) accounts for the negative interference. Quenching of HO fluorescence by the modulating reagent contributes a smaller positive term to the interference; kinetic measurements of the quenching rate coefficient are reported. The experimental interference results are compared with a detailed kinetic model of HO production, excitation, relaxation, and detection; reasonable agreement is found.

Heterotopic ossification in civilians with lower limb amputations.

PubMed

Matsumoto, Mary E; Khan, Mohammed; Jayabalan, Prakash; Ziebarth, Jessica; Munin, Michael C

2014-09-01

To report the incidence of symptomatic heterotopic ossification (HO) in a defined civilian amputee population, describe its characteristics, and compare these findings to published data in military amputees. Retrospective chart analysis from July 1998 to July 2009. Ambulatory amputee clinic within a large university medical center. Adults with lower limb amputation (N=158). Not applicable. Patients with symptomatic HO confirmed by radiographs. A total of 261 patients were evaluated; 158 met inclusion criteria, with 59% having traumatic etiology, 18% vascular etiology, 22% infection, and 1% tumor. Symptomatic HO was diagnosed in 36 (22.8%) patients, and 94% patients had mild HO on radiographic scoring. Rate of HO in amputations related to trauma was not increased compared with those of other etiologies. Surgical resection of the ectopic bone was required in 4 (11%) patients. HO is seen commonly after civilian lower limb amputation regardless of etiology. The prevalence was less than that observed in previous reports from military populations. This is the first report estimating the prevalence of HO in adult civilian amputees. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A comprehensive analysis of heavy metals in urban road dust of Xi'an, China: Contamination, source apportionment and spatial distribution.

PubMed

Pan, Huiyun; Lu, Xinwei; Lei, Kai

2017-12-31

A detailed investigation was conducted to study heavy metal contamination in road dust from four regions of Xi'an, Northwest China. The concentrations of eight heavy metals Co, Cr, Cu, Mn, Ni, Pb, Zn and V were determined by X-Ray Fluorescence. The mean concentrations of these elements were: 30.9mgkg -1 Co, 145.0mgkg -1 Cr, 54.7mgkg -1 Cu, 510.5mgkg -1 Mn, 30.8mgkg -1 Ni, 124.5mgkg -1 Pb, 69.6mgkg -1 V and 268.6mgkg -1 Zn. There was significant enrichment of Pb, Zn, Co, Cu and Cr based on geo-accumulation index value. Multivariate statistical analysis showed that levels of Cu, Pb, Zn, Co and Cr were controlled by anthropogenic activities, while levels of Mn, Ni and V were associated with natural sources. Principle component analysis and multiple linear regression were applied to determine the source apportionment. The results showed that traffic was the main source with a percent contribution of 53.4%. Natural sources contributed 26.5%, and other anthropogenic pollution sources contributed 20.1%. Clear heavy metal pollution hotspots were identified by GIS mapping. The location of point pollution sources and prevailing wind direction were found to be important factors in the spatial distribution of heavy metals. Copyright © 2017 Elsevier B.V. All rights reserved.

High-grade iron ore at Windarling, Yilgarn Craton: a product of syn-orogenic deformation, hypogene hydrothermal alteration and supergene modification in an Archean BIF-basalt lithostratigraphy

NASA Astrophysics Data System (ADS)

Angerer, Thomas; Hagemann, Steffen G.; Danyushevsky, Leonid

2013-08-01

Banded iron formation (BIF)-hosted iron ore deposits in the Windarling Range are located in the lower greenstone succession of the Marda-Diemals greenstone belt, Southern Cross domain, Yilgarn Craton and constitute a total hematite-martite-goethite ore resource of minimum 52 Mt at 60 wt.% Fe (0.07 P). Banded iron formation is interlayered with high-Mg basalts at Windarling and precipitated during episodes of volcanic quiescence. Trace element content and the rare earth element (REE) ratios Y/Ho (42 to 45), Sm/Yb (1.5), together with positive La and Gd anomalies in `least-altered' hematite-magnetite-metachert-BIF indicate the precipitation from Archean seawater that was fertilised by hydrothermal vent fluids with a basaltic HREE-Y signature. Hypogene iron ore in sub-greenschist facies metamorphosed BIF formed during three distinct stages: ore stage 1 was a syn- to post-metamorphic, syn-D1, Fe-Ca-Mg-Ni-Co-P-REE metasomatism that produced local Ni-REE-rich Fe-dolomite-magnetite alteration in BIF. Hydrothermal alteration was induced by hot fluid flow controlled by brittle-ductile reactivation of BIF-basalt margins and crosscutting D1 faults. The Ni-Co-rich content of dolomite and a shift in REE ratios in carbonate-altered BIF towards Archean mafic rock signature (Y/Ho to 31 to 40, Sm/Yb to 1 to 2 and Gd/Gd* to 1.2 to 1.4) suggest that high-Mg basalts in the Windarling Range were the primary source of introduced metals. During ore stage 2, a syn-deformational and likely acidic and oxidised fluid flow along BIF-basalt margins and within D1 faults leached carbonate and precipitated lepidoblastic and anhedral/granoblastic hematite. High-grade magnetite-hematite ore is formed during this stage. Ore stage 3 hydrothermal specular hematite (spcH)-Fe-dolomite-quartz alteration was controlled by a late-orogenic, brittle, compressional/transpressional stage (D4; the regional-scale shear-zone-related D3 is not preserved in Windarling). This minor event remobilised iron oxides, carbonate and quartz to form veins and breccia but did not generate significant volumes of iron ore. Ore stage 4 involved Mesozoic(?) to recent supergene oxidation and hydration in a weathering environment reaching down to depths of ˜100 to maximum 200 m below surface. Supergene ore formation involved goethite replacement of dolomite and quartz as well as martitisation. Important `ground preparation' for supergene modification and upgrade were mainly the formation of steep D1 to D4 structures, steep BIF/basalt margins and particularly the syn-D1 to syn-D2 carbonate alteration of BIF that is most susceptible to supergene dissolution. The Windarling deposits are structurally controlled, supergene-modified hydrothermal iron ore systems that share comparable physical, chemical and ore-forming characteristics to other iron ore deposits in the Yilgarn Craton (e.g. Koolyanobbing, Beebyn in the Weld Range, Mt. Gibson). However, the remarkable variety in pre-, syn- and post-deformational ore textures (relative to D1 and D2) has not been described elsewhere in the Yilgarn and are similar to the ore deposits in high-strain zones, such as of Brazil (Quadrilátero Ferrífero or Iron Quadrangle) and Nigeria. The overall similarity of alteration stages, i.e. the sequence of hydrothermal carbonate introduction and hypogene leaching, with other greenstone belt-hosted iron ore deposits supports the interpretation that syn-orogenic BIF alteration and upgrade was crucial in the formation of hypogene-supergene iron ore deposits in the Yilgarn Craton and possibly in other Archean/Paleoproterozoic greenstone belt settings worldwide.

The ecological risk, source identification, and pollution assessment of heavy metals in road dust: a case study in Rafsanjan, SE Iran.

PubMed

Mirzaei Aminiyan, Milad; Baalousha, Mohammed; Mousavi, Rouhollah; Mirzaei Aminiyan, Farzad; Hosseini, Hamideh; Heydariyan, Amin

2018-05-01

Heavy metal (HM) contamination in road dust is a potential environmental and human health threat. The sources, concentrations, spatial distribution, and ecological risk of As, Cd, Cu, Cr, Ni, Pb, and Zn in road dust in Rafsanjan City, Iran, were investigated. Pollution was assessed using the enrichment factor (EF). The potentially harmful effects of HMs were evaluated by calculating the potential ecological risk factor of individual metals (E r ) and of multiple metals (RI) using the Hakanson method. Correlation and principal component analyses (PCA) were applied to identify HM pollution sources. The concentrations of HMs in road dust were higher (ca. 5-10 folds) than their natural background values. The EF and E r increased according to the following order Cu > Pb > As > Zn > Cd > Cr > Ni and Cu > Cd > Pb > As > Ni > Zn > Cr, respectively. Thus, Cu is regarded as the pollutant of highest concern. Based on potential ecological risk index (RI) spatial distribution, all parts of Rafsanjan are characterized by significantly high potential ecological risk. HM concentration heat maps, PCA, and correlation analysis suggest that Cu, Pb, As, Cd, and Zn may have originated from the same source and follow the same spatial distribution pattern. These metals originated mainly from anthropogenic sources like copper mining and smelting plants, industrial and chemical activities, inordinate application of chemical fertilizers and pesticides in farmlands, and heavy traffic. Ni and Cr are likely to origniate from the industrial activities and traffic load in Rafsanjan City.

Nitric oxide and iron modulate heme oxygenase activity as a long distance signaling response to salt stress in sunflower seedling cotyledons.

PubMed

Singh, Neha; Bhatla, Satish C

2016-02-29

Nitric oxide is a significant component of iron signaling in plants. Heme is one of the iron sensors in plants. Free heme is highly toxic and can cause cell damage as it catalyzes the formation of reactive oxygen species (ROS). Its catabolism is carried out by heme oxygenase (HOs; EC 1.14.99.3) which uses heme both as a prosthetic group and as a substrate. Two significant events, which accompany adaptation to salt stress in sunflower seedlings, are accumulation of ROS and enhanced production of nitric oxide (NO) in roots and cotyledons. Present investigations on the immunolocalization of heme oxygenase distribution in sunflower seedling cotyledons by confocal laser scanning microscopic (CLSM) imaging provide new information on the differential spatial distribution of the inducible form of HO (HO-1) as a long distance in response to NaCl stress. The enzyme is abundantly distributed in the specialized cells around the secretory canals (SCs) in seedling cotyledons. Abundance of tyrosine nitrated proteins has also been observed in the specialized cells around the secretory canals in cotyledons derived from salt stressed seedlings. The spatial distribution of tyrosine nitrated proteins and HO-1 expression further correlates with the abundance of mitochondria in these cells. Present findings, thus, highlight a link among distribution of HO-1 expression, abundance of tyrosine nitrated proteins and mitochondria in specialized cells around the secretory canal as a long distance mechanism of salt stress tolerance in sunflower seedlings. Enhanced spatial distribution of HO-1 in response to NaCl stress in seedling cotyledons is in congruence with the observed increase in specific activity of HO-1 in NaCl stressed conditions. The enzyme activity is further enhanced by hemin (HO-1 inducer) both in the absence or presence of NaCl stress and inhibited by zinc protoporphyrin. Western blot analysis of cotyledon homogenates using anti-HO-1 polyclonal antibody shows one major band (29 kDa) of HO-1. NaCl-modulated HO-1 activity correlates with endogenous NO content in the cotyledons. Increased NO accumulation by hemin treatment also correlates with enhanced activity of HO-1 in both control and NaCl stress conditions. Present work indicates that NO positively modulates HO-1 activity in sunflower seedling cotyledons. NaCl stress tends to antagonize NO action on HO-1 activity. NO (from sodium nitroprusside; SNP) is probably positively modulating HO-1 activity by way of its interaction/binding with heme group. Present work also shows enhanced NO accumulation in seedling cotyledons both in the absence or presence of iron in the growth medium, in response to NaCl stress. Thus, a probable link between endogenous NO, NaCl stress and iron-homeostasis by way of modulation of HO-1 activity at early stage of sunflower seedling growth has been proposed. Copyright © 2016 Elsevier Inc. All rights reserved.

One-Pot Solvothermal in Situ Growth of 1D Single-Crystalline NiSe on Ni Foil as Efficient and Stable Transparent Conductive Oxide Free Counter Electrodes for Dye-Sensitized Solar Cells.

PubMed

Bao, Chao; Li, Faxin; Wang, Jiali; Sun, Panpan; Huang, Niu; Sun, Yihua; Fang, Liang; Wang, Lei; Sun, Xiaohua

2016-12-07

One-dimensional single-crystal nanostructural nickel selenides were successfully in situ grown on metal nickel foils by two simple one-step solvothermal methods, which formed NiSe/Ni counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The nickel foil acted as the nickel source in the reaction process, a supporting substrate, and an electron transport "speedway". Electrochemical testing indicated that the top 1D single-crystal NiSe exhibited prominent electrocatalytic activity for I 3 - reduction. Due to the metallic conductivity of Ni substrate and the outstanding electrocatalytic activity of single-crystal NiSe, the DSSC based on a NiSe/Ni CE exhibited higher fill factor (FF) and larger short-circuit current density (J sc ) than the DSSC based on Pt/FTO CE. The corresponding power conversion efficiency (6.75%) outperformed that of the latter (6.18%). Moreover, the NiSe/Ni CEs also showed excellent electrochemical stability in the I - /I 3 - redox electrolyte. These findings indicated that single-crystal NiSe in situ grown on Ni substrate was a potential candidate to replace Pt/TCO as a cheap and highly efficient counter electrode of DSSC.

Employee Attitudes of the Organizational Culture: Assessment of a TQM implementation Process

DTIC Science & Technology

1990-09-01

68 Analysis of Hypotheses..............70 Null Hypotheses Hola -Holi .............. 71 T-test...............................71 Summary of...Analyses for Hola -Holi 72 Null Hypotheses Ho2a-Ho2i .............. 73 One-way Analysis of Variance ......... 73 Summary of Analyses for Ho2a-Ho2i .... 77...supervisory and non- supervisory organizational members with regard to their attitudes about the organization’s quality culture. Hola . There will be no

Ho-nanoparticle-doping for improved high-energy laser fibers

NASA Astrophysics Data System (ADS)

Friebele, E. Joseph; Baker, Colin C.; Burdett, Ashley A.; Rhonehouse, Daniel L.; Bowman, Steven R.; Kim, Woohong; Sanghera, Jasbinder S.; Kucera, Courtney; Vargas, Amber; Ballato, John; Hemming, Alexander; Simakov, Nikita; Haub, John

2017-02-01

A significant issue for holmium-doped fiber lasers (HoDFLs) operating near 2 μm is multiphonon quenching due to the high phonon energy 1100 cm-1 of the silica host, which complicates power scaling due to reduced lifetimes and increased heating. Nanoparticle (NP) doping is a new technique where the structure surrounding the Ho ions is developed chemically prior to doping into the silica core. We have incorporated Ho3+ ions into various NPs, such as LaF3, Al2O3 and Lu2O3, to shield them from the silica glass matrix. Results indicate slightly longer lifetimes with Ho:LaF3 NPs and the possibility of further improvement with oxide NPs. We report the first of lasing in a Ho:Lu2O3 NP-doped fiber pumped at 1.95 μm and operating at 2.09 μm with a record slope efficiency of 85.2%.

Improvement of heavy dopant doped Ni-silicide using ytterbium interlayer for nano-scale MOSFETS with an ultra shallow junction.

PubMed

Shin, Hong-Sik; Oh, Se-Kyung; Kang, Min-Ho; Li, Shi-Guang; Lee, Ga-Won; Lee, Hi-Deok

2011-07-01

In this paper, a novel Ni silicide with Yb interlayer (Yb/Ni/TiN) on a boron cluster (B18H22) implanted source/drain junction is proposed for the first time, and its thermal stability characteristics are analyzed in depth. The proposed Ni-silicide exhibits a wider RTP temperature window for uniform sheet resistance, surface roughness and better thermal stability than the conventional structure (Ni/TiN). In addition, the cross-sectional profile of the proposed Ni-silicide showed less agglomeration despite the high temperature post-silicidation annealing, and it can be said that the proposed structure was little dependence on the temperature post-silicidation annealing. The improvement of Ni silicide properties is analyzed and found to be due to the formation of the rare earth metal--NiSi (YbNi2Si2), whose peaks were confirmed by XRD. The junction leakage current of the p + -n junction with Yb/Ni/TiN and B18H22 implantation is smaller than that with Ni/TiN by almost one order of magnitude as well as improving the thermal stability of ultra shallow junction.

Intensity and Energy Level Analysis of the Vacuum Ultraviolet Spectrum of Four Times Ionize Nickel (Ni V)

NASA Astrophysics Data System (ADS)

Ward, Jacob Wolfgang; Nave, Gillian

2016-01-01

Recent measurements of four times ionized iron and nickel (Fe V & Ni V) wavelengths in the vacuum ultraviolet (VUV) have been taken using the National Institute for Standards and Technology (NIST) Normal Incidence Vacuum Spectrograph (NIVS) with a sliding spark light source with invar electrodes. The wavelengths observed in those measurements make use of high resolution photographic plates with the majority of observed lines having uncertainties of approximately 3mÅ. In addition to observations made with photographic plates, the same wavelength region was observed with phosphor image plates, which have been demonstrated to be accurate as a method of intensity calibration when used with a deuterium light source. This work will evaluate the use of phosphor image plates and deuterium lamps as an intensity calibration method for the Ni V spectrum in the 1200-1600Å region of the VUV. Additionally, by pairing the observed wavelengths of Ni V with accurate line intensities, it is possible to create an energy level optimization for Ni V providing high accuracy Ritz wavelengths. This process has previously been applied to Fe V and produced Ritz wavelengths that agreed with the above experimental observations.

Heme Oxygenase Inhibition Sensitizes Neuroblastoma Cells to Carfilzomib.

PubMed

Barbagallo, Ignazio; Giallongo, Cesarina; Volti, Giovanni Li; Distefano, Alfio; Camiolo, Giuseppina; Raffaele, Marco; Salerno, Loredana; Pittalà, Valeria; Sorrenti, Valeria; Avola, Roberto; Di Rosa, Michelino; Vanella, Luca; Di Raimondo, Francesco; Tibullo, Daniele

2018-06-10

Neuroblastoma (NB) is an embryonic malignancy affecting the physiological development of adrenal medulla and paravertebral sympathetic ganglia in early infancy. Proteasome inhibitors (PIs) (i.e., carfilzomib (CFZ)) may represent a possible pharmacological treatment for solid tumors including NB. In the present study, we tested the effect of a novel non-competitive inhibitor of heme oxygenase-1 (HO-1), LS1/71, as a possible adjuvant therapy for the efficacy of CFZ in neuroblastoma cells. Our results showed that CFZ increased both HO-1 gene expression (about 18-fold) and HO activity (about 8-fold), following activation of the ER stress pathway. The involvement of HO-1 in CFZ-mediated cytotoxicity was further confirmed by the protective effect of pharmacological induction of HO-1, significantly attenuating cytotoxicity. In addition, HO-1 selective inhibition by a specific siRNA increased the cytotoxic effect following CFZ treatment in NB whereas SnMP, a competitive pharmacological inhibitor of HO, showed no changes in cytotoxicity. Our data suggest that treatment with CFZ produces ER stress in NB without activation of CHOP-mediated apoptosis, whereas co-treatment with CFZ and LS1/71 led to apoptosis activation and CHOP expression induction. In conclusion, our study showed that treatment with the non-competitive inhibitor of HO-1, LS1 / 71, increased cytotoxicity mediated by CFZ, triggering apoptosis following ER stress activation. These results suggest that PIs may represent a possible pharmacological treatment for solid tumors and that HO-1 inhibition may represent a possible strategy to overcome chemoresistance and increase the efficacy of chemotherapic regimens.

High oleic ready-to-use therapeutic food maintains docosahexaenoic acid status in severe malnutrition: a randomized, blinded trial

PubMed Central

Hsieh, Ji-Cheng; Liu, Lei; Zeilani, Mamane; Ickes, Scott; Trehan, Indi; Maleta, Ken; Craig, Christina; Thakwalakwa, Chrissie; Singh, Lauren; Brenna, J. Thomas; Manary, Mark J.

2015-01-01

Objective Ready-to-use therapeutic food (RUTF) is the preferred treatment for uncomplicated severe acute malnutrition. RUTF contains large amounts of linoleic acid and very little α-linolenic acid, which may reduce the availability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to the recovering child. A novel high oleic RUTF (HO-RUTF) was developed with less linoleic acid to determine its effect on DHA and EPA status. Methods We conducted a prospective, randomized, double-blinded, clinical effectiveness trial treating rural Malawian children with severe acute malnutrition. Children were treated with either HO-RUTF or standard RUTF. Plasma phospholipid (PL) fatty acid status was measured upon enrollment and after 4 weeks and compared between the two intervention groups. Results Among the 141 children enrolled, 48/71 receiving HO-RUTF and 50/70 receiving RUTF recovered. Plasma PL samples were analyzed from 43 children consuming HO-RUTF and 35 children consuming RUTF. The change in DHA content during the first 4 weeks was +4% and −25% in the HO-RUTF and RUTF groups, respectively (P = 0.04). For EPA, the change in content was 63% and −24% in the HO-RUTF and RUTF groups (P < 0.001). For arachidonic acid, the change in content was −3% and 13% in the HO-RUTF and RUTF groups (P < 0.009). Conclusions The changes in DHA and EPA seen in the children treated with HO-RUTF warrant further investigation as they suggest HO-RUTF support improved PUFA status, necessary for neural development and recovery. PMID:25633498

Solution 1H NMR investigation of the active site molecular and electronic structures of substrate-bound, cyanide-inhibited HmuO, a bacterial heme oxygenase from Corynebacterium diphtheriae.

PubMed

Li, Yiming; Syvitski, Ray T; Chu, Grace C; Ikeda-Saito, Masao; Mar, Gerd N La

2003-02-28

The molecular structure and dynamic properties of the active site environment of HmuO, a heme oxygenase (HO) from the pathogenic bacterium Corynebacterium diphtheriae, have been investigated by (1)H NMR spectroscopy using the human HO (hHO) complex as a homology model. It is demonstrated that not only the spatial contacts among residues and between residues and heme, but the magnetic axes that can be related to the direction and magnitude of the steric tilt of the FeCN unit are strongly conserved in the two HO complexes. The results indicate that very similar contributions of steric blockage of several meso positions and steric tilt of the attacking ligand are operative. A distal H-bond network that involves numerous very strong H-bonds and immobilized water molecules is identified in HmuO that is analogous to that previously identified in hHO (Li, Y., Syvitski, R. T., Auclair, K., Wilks, A., Ortiz de Montellano, P. R., and La Mar, G. N. (2002) J. Biol. Chem. 277, 33018-33031). The NMR results are completely consistent with the very recent crystal structure of the HmuO.substrate complex. The H-bond network/ordered water molecules are proposed to orient the distal water molecule near the catalytically key Asp(136) (Asp(140) in hHO) that stabilizes the hydroperoxy intermediate. The dynamic stability of this H-bond network in HmuO is significantly greater than in hHO and may account for the slower catalytic rate in bacterial HO compared with mammalian HO.

Role of the heme oxygenases in abnormalities of the mesenteric circulation in cirrhotic rats.

PubMed

Sacerdoti, David; Abraham, Nader G; Oyekan, Adebayo O; Yang, Liming; Gatta, Angelo; McGiff, John C

2004-02-01

Carbon monoxide (CO), a product of heme metabolism by heme-oxygenase (HO), has biological actions similar to those of nitric oxide (NO). The role of CO in decreasing vascular responses to constrictor agents produced by experimental cirrhosis induced by carbon tetrachloride was evaluated before and after inhibition of HO with tin-mesoporphyrin (SnMP) in the perfused superior mesenteric vasculature (SMV) of cirrhotic and normal rats and in normal rats transfected with the human HO-1 (HHO-1) gene. Perfusion pressure and vasoconstrictor responses of the SMV to KCl, phenylephrine (PE), and endothelin-1 (ET-1) were decreased in cirrhotic rats. SnMP increased SMV perfusion pressure and restored the constrictor responses of the SMV to KCl, PE, and ET-1 in cirrhotic rats. The relative roles of NO and CO in producing hyporeactivity of the SMV to PE in cirrhotic rats were examined. Vasoconstrictor responses to PE were successively augmented by stepwise inhibition of CO and NO production, suggesting a complementary role for these gases in the regulation of reactivity of the SMV. Expression of constitutive but not of inducible HO (HO-1) was increased in the SMV of cirrhotic rats as was HO activity. Administration of adenovirus containing HHO-1 gene produced detection of HHO-1 RNA and increased HO activity in the SMV within 7 days. Rats transfected with HO-1 demonstrated reduction in both perfusion pressure and vasoconstrictor responses to PE in the SMV. We propose that HO is an essential component in mechanisms that modulate reactivity of the mesenteric circulation in experimental hepatic cirrhosis in rats.

Functional imaging: monitoring heme oxygenase-1 gene expression in vivo

NASA Astrophysics Data System (ADS)

Zhang, Weisheng; Reilly-Contag, Pamela; Stevenson, David K.; Contag, Christopher H.

1999-07-01

The regulation of genetic elements can be monitored in living animals using photoproteins as reporters. Heme oxygenase (HO) is the key catabolic enzyme in the heme degradation pathway. Here, HO expression serves as a model for in vivo functional imaging of transcriptional regulation of a clinically relevant gene. HO enzymatic activity is inhibited by heme analogs, metalloporphyrins, but many members of this family of compounds also activate transcription of the HO-1 promoter. The degree of transcriptional activation by twelve metalloporphyrins, differing at the central metal and porphyrin ring substituents, was evaluated in both NIH 3T3 stable lines and transgenic animals containing HO-1 promoter-luciferase gene fusions. In the correlative cell culture assays, the metalloporphyrins increased transcription form the full length HO promoter fusion to varying degrees, but none increased transcription from a truncated HO-1 promoter. These results suggested that one or both of the two distal enhancer elements located at -4 and -10 Kb upstream from transcriptional start are required for HO-1 induction by heme and its analogs. The full-length HO-1-luc fusion was then evaluated as a transgene in mice. It was possible to monitor the effects of the metalloporphyrins, SnMP and ZnPP, in living animals over time. This spatiotemporal analyses of gene expression in vivo implied that alterations in porphyrin ring substituents and the central metal may affect the extent of gene activation. These data further indicate that using photoprotein reporters, subtle differences in gene expression can be monitored in living animals.

Adverse effect on syngeneic islet transplantation by transgenic coexpression of decoy receptor 3 and heme oxygenase-1 in the islet of NOD mice.

PubMed

Huang, S-H; Lin, G-J; Chien, M-W; Chu, C-H; Yu, J-C; Chen, T-W; Hueng, D-Y; Liu, Y-L; Sytwu, H-K

2013-03-01

Decoy receptor 3 (DcR3) blocks both Fas ligand- and LIGHT-induced pancreatic β-cell damage in autoimmune diabetes. Heme oxygenase 1 (HO-1) possesses antiapoptotic, anti-inflammatory, and antioxidative effects that protect cells against various forms of attack by the immune system. Previously, we have demonstrated that transgenic islets overexpressing DcR3 or murine HO-1 (mHO-1) exhibit longer survival times than nontransgenic islets in syngeneic islet transplantation. In this study, we evaluated whether DcR3 and mHO-1 double-transgenic islets of NOD mice could provide better protective effects and achieve longer islet graft survival than DcR3 or mHO-1 single-transgenic islets after islet transplantation. We generated DcR3 and mHO-1 double-transgenic NOD mice that specifically overexpress DcR3 and HO-1 in islets. Seven hundred islets isolated from double-transgenic, single-transgenic, or nontransgenic NOD mice were syngeneically transplanted into the kidney capsules of newly diabetic female recipients. Unexpectedly, there was no significant difference in the survival time between double-transgenic or nontransgenic NOD islet grafts, and the survival times of double-transgenic NOD islet grafts were even shorter than those of DcR3 or mHO-1 single-transgenic islets. Our data indicate that transplantation of double-transgenic islets that coexpress HO-1 and DcR3 did not result in a better outcome. On the contrary, this strategy even caused an adverse effect in syngeneic islet transplantation. Copyright © 2013 Elsevier Inc. All rights reserved.

Galantamine and carbon monoxide protect brain microvascular endothelial cells by heme oxygenase-1 induction

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

Nakao, Atsunori; Thomas E Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213; Kaczorowski, David J.

2008-03-14

Galantamine, a reversible inhibitor of acetylcholine esterase (AChE), is a novel drug treatment for mild to moderate Alzheimer's disease and vascular dementia. Interestingly, it has been suggested that galantamine treatment is associated with more clinical benefit in patients with mild-to-moderate Alzheimer disease compared to other AChE inhibitors. We hypothesized that the protective effects of galantamine would involve induction of the protective gene, heme oxygenase-1 (HO-1), in addition to enhancement of the cholinergic system. Brain microvascular endothelial cells (mvECs) were isolated from spontaneous hypertensive rats. Galantamine significantly reduced H{sub 2}O{sub 2}-induced cell death of mvECs in association with HO-1 induction. Thesemore » protective effects were completely reversed by nuclear factor-{kappa}B (NF-{kappa}B) inhibition or HO inhibition. Furthermore, galantamine failed to induce HO-1 in mvECs which lack inducible nitric oxide synthase (iNOS), supplementation of a nitric oxide (NO) donor or iNOS gene transfection on iNOS-deficient mvECs resulted in HO-1 induction with galantamine. These data suggest that the protective effects of galantamine require NF-{kappa}B activation and iNOS expression, in addition to HO-1. Likewise, carbon monoxide (CO), one of the byproducts of HO, up-regulated HO-1 and protected mvECs from oxidative stress in a similar manner. Our data demonstrate that galantamine mediates cytoprotective effects on mvECs through induction HO-1. This pharmacological action of galantamine may, at least in part, account for the superior clinical efficacy of galantamine in vascular dementia and Alzheimer disease.« less

Norharmane rhenium(I) polypyridyl complexes: synthesis, structural and spectroscopic characterization.

PubMed

Maisuls, Iván; Wolcan, Ezequiel; Piro, Oscar E; Etcheverría, Gustavo A; Petroselli, Gabriela; Erra-Ballsels, Rosa; Cabrerizo, Franco M; Ruiz, Gustavo T

2015-10-21

Two novel Re(i) complexes with the general formula fac-[Re(CO)3(L)(nHo)]CF3SO3, where L = 2,2'-bipyridine (bpy) or 1,10 phenanthroline (phen) and nHo (9H-pyrido[3,4-b]indole; norharmane) have been synthesized. The Re(i)-nHo complexes were characterized by structural X-ray diffraction, (1)H and (13)C NMR, UV-vis absorption and FT-IR spectroscopy, and by a combination of two mass spectrometry techniques, namely ESI-MS and UV-MALDI-MS. All characterizations showed that nHo is coordinated to the metal atom by the pyridine nitrogen of the molecule. X-ray structural analysis revealed that the crystal lattices for both complexes are further stabilized by a strong >N-HO bond between the pyrrole NH group of the pyridoindole ligand and one oxygen atom of the trifluoromethanesulfonate counter-ion. Ground state geometry optimization by DFT calculations showed that in fluid solution the nHo ligand may rotate freely. The nature of the electronic transitions of Re(CO)3(bpy)(nHo)(+) were established by TD-DFT calculations. The set of the most important electronic transitions present in this complex are comprised of π→π* electronic transitions centered on bpy and nHo moieties, LLCTnHo→COs, MLLCTRe(CO)3→bpy and LLCTnHo→bpy transitions. Additionally, TD-DFT calculations predict the existence of another two intense MLLCTRe(CO)3→nHo electronic transitions. Calculated UV-vis absorption spectra are in good agreement with the corresponding experimental data for the bpy-containing complex.

Development of flashlamp-pumped Q-switched Ho:Tm:Cr:YAG lasers for mid-infrared LIDAR application

NASA Technical Reports Server (NTRS)

Choi, Young S.; Kim, Kyong H.; Whitney, Donald A.; Hess, Robert V.; Barnes, Norman P.; Bair, Clayton H.; Brockman, Philip

1989-01-01

A flashlamp-pumped 2.1 micron Ho:Tm:Cr:YAG laser was studied for both normal mode and Q-switched operations under a wide variety of experimental conditions in order to optimize performance. Laser output energy, slope efficiency, threshold and pulselength were determined as a function of operating temperature, output mirror reflectivity, input electrical energy and Q-switch opening time. The measured normal-mode laser thresholds of a Ho(3+) (0.45 atomic percent):Tm(3+) (2.5 atomic percent):Cr(3+) (0.8 atomic percent):YAG crystal ranged form 26 to 50 J between 120 and 200 K with slope efficiencies up to 0.36 percent with a 60 percent reflective output mirror. Under Q-switched operation the slope efficiency was 90 percent of the normal-mode result. Development of solid state lasers with Ho(3+), Tm(3+) and/or Er(3+) doped crystals has been pursued by NASA for eye-dafe mid-infrared LIDAR (light detection and ranging) application. As a part of the project, the authors have been working on evaluating Ho(3+):Tm(3+):Cr(3+):YAG crystals for normal-mode and Q-switched 2.1 micron laser operations in order to determine an optimum Tm(3+) concentration under flashlamp pumping conditions. Lasing properties of the Ho(3+) in the mid-infrared region have been studied by many research groups since the early 1960's. However, the technology of those lasers is still premature for lidar application. In order to overcome the inefficiency related to narrow absorption bands of the Ho(3+), Tm(3+) and Er(3+), the erbium has been replaced by chromium. The improvement in flashlamp-pumped Ho(3+) laser efficiency has been demonstrated recently by several research groups by utilizing the broad absorption spectrum of Cr(3+) which covers the flashlamp's emission spectrum. Efficient energy transfer to the Tm(3+) and then the Ho(3+) occurs subsequently. It is known that high Tm(3+) concentration and low Ho(3+) concentration are preferred to achieve a quantum efficiency approaching two and to avoid large reabsorption losses. However, determination of the optimum Tm(3+) concentration required to ensure efficient energy transfer from Cr(3+) to Tm(3+) and from Tm(3+) to Ho(3+) has not been made in the Ho:Tm:CR:YAG crystal. The results obtained so far are given.

Transgenic expression of human heme oxygenase-1 in pigs confers resistance against xenograft rejection during ex vivo perfusion of porcine kidneys.

PubMed

Petersen, Björn; Ramackers, Wolf; Lucas-Hahn, Andrea; Lemme, Erika; Hassel, Petra; Queisser, Anna-Lisa; Herrmann, Doris; Barg-Kues, Brigitte; Carnwath, Joseph W; Klose, Johannes; Tiede, Andreas; Friedrich, Lars; Baars, Wiebke; Schwinzer, Reinhard; Winkler, Michael; Niemann, Heiner

2011-01-01

The major immunological hurdle to successful porcine-to-human xenotransplantation is the acute vascular rejection (AVR), characterized by endothelial cell (EC) activation and perturbation of coagulation. Heme oxygenase-1 (HO-1) and its derivatives have anti-apoptotic, anti-inflammatory effects and protect against reactive oxygen species, rendering HO-1 a promising molecule to control AVR. Here, we report the production and characterization of pigs transgenic for human heme oxygenase-1 (hHO-1) and demonstrate significant protection in porcine kidneys against xenograft rejection in ex vivo perfusion with human blood and transgenic porcine aortic endothelial cells (PAEC) in a TNF-α-mediated apoptosis assay. Transgenic and non-transgenic PAEC were tested in a TNF-α-mediated apoptosis assay. Expression of adhesion molecules (ICAM-1, VCAM-1, and E-selectin) was measured by real-time PCR. hHO-1 transgenic porcine kidneys were perfused with pooled and diluted human AB blood in an ex vivo perfusion circuit. MHC class-II up-regulation after induction with IFN-γ was compared between wild-type and hHO-1 transgenic PAEC. Cloned hHO-1 transgenic pigs expressed hHO-1 in heart, kidney, liver, and in cultured ECs and fibroblasts. hHO-1 transgenic PAEC were protected against TNF-α-mediated apoptosis. Real-time PCR revealed reduced expression of adhesion molecules like ICAM-1, VCAM-1, and E-selectin. These effects could be abrogated by the incubation of transgenic PAECs with the specific HO-1 inhibitor zinc protoporphorine IX (Zn(II)PPIX, 20 μm). IFN-γ induced up-regulation of MHC class-II molecules was significantly reduced in PAECs from hHO-1 transgenic pigs. hHO-1 transgenic porcine kidneys could successfully be perfused with diluted human AB-pooled blood for a maximum of 240 min (with and without C1 inh), while in wild-type kidneys, blood flow ceased after ∼60 min. Elevated levels of d-Dimer and TAT were detected, but no significant consumption of fibrinogen and antithrombin was determined. Microthrombi could not be detected histologically. These results are encouraging and warrant further studies on the biological function of heme oxygenase-I expression in hHO-1 transgenic pigs in the context of xenotransplantation. © 2011 John Wiley & Sons A/S.

Heme oxygenase-1 system and gastrointestinal tumors

PubMed Central

Zhu, Xiao; Fan, Wen-Guo; Li, Dong-Pei; Lin, Marie CM; Kung, Hsiangfu

2010-01-01

Heme oxygenase-1 (HO-1) system catabolizes heme into three products: carbon monoxide, biliverdin/bilirubin and free iron. It is involved in many physiological and pathophysiological processes. A great deal of data has demonstrated the roles of HO-1 in the formation, growth and metastasis of tumors. The interest in this system by investigators involved in gastrointestinal tumors is fairly recent, and few papers on HO-1 have touched upon this subject. This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal tumors studied to date. The implications for possible therapeutic manipulation of HO-1 in gastrointestinal tumors are also discussed. PMID:20518085

Anisotropic magnetocaloric effect in HoAlGa polycrystalline compound

NASA Astrophysics Data System (ADS)

Yan, Zhang; Xinqi, Zheng; JieFu, Xiong; Shulan, Zuo; Qiaoyan, Dong; Tongyun, Zhao; Baogen, Shen

2018-05-01

In this work, a nonnegligible anisotropic magnetocaloric effect (MCE) in HoAlGa polycrystalline compounds has been observed. With temperature increasing, the HoAlGa compound undergoes two kinds of magnetic transitions at 19 K and 31 K, respectively, the later has been recognized as an ordinary antiferromagnetic to paramagnetic (AFM-PM) transition. The -ΔS peak of HoAGa reaches 5.4 J/kg K and 1.5 J/kg K at 35 K along parallel and perpendicular texture directions respectively, for a field change of 0-5 T. The result indicates that the HoAlGa polycrystalline compounds with excellent anisotropic MCE can be expected to have effective magnetic refrigeration applications in low temperature range.

Reliability and Validity of the HoNOS-LD and HoNOS in a Sample of Individuals with Mild to Borderline Intellectual Disability and Severe Emotional and Behavior Disorders

ERIC Educational Resources Information Center

Tenneij, Nienke; Didden, Robert; Veltkamp, Eline; Koot, Hans M.

2009-01-01

In this study, psychometric properties of the Health of the Nation Outcome scales (HoNOS) and Health of the Nation Outcome Scales for People with Learning Disabilities (HoNOS-LD) were investigated in a sample (n = 79) of (young) adults with mild to borderline intellectual disability (ID) and severe behavior and mental health problems who were…

Early Diagnosis and Intervention Strategies for Post-Traumatic Heterotopic Ossification in Severely Injured Extremities

DTIC Science & Technology

2013-10-01

study will recruit wounded warriors with severe extremity trauma, which places them at high risk for heterotopic ossification (HO); bone formation at...involved in HO; 2) to define accurate and practical methods to predict where HO will develop; and 3) to define potential therapies for prevention or...elicit HO. These tools also need to provide effective methods for early diagnosis or risk assessment (prediction) so that therapies for prevention or

High-power and highly efficient diode-cladding-pumped Ho3+-doped silica fiber lasers.

PubMed

Jackson, Stuart D; Bugge, Frank; Erbert, Götz

2007-11-15

We demonstrate high-power operation from a singly Ho3+-doped silica fiber laser that is cladding pumped directly with diode lasers operating at 1150 nm. Internal slope efficiencies approaching the Stokes limit were produced, and the maximum output power was 2.2W. This result was achieved using a low Ho3+-ion concentration and La3+-ion codoping, which together limit the transfer of energy between excited Ho3+ ions.

Heme oxygenase 1 defects lead to reduced chlorophyll in Brassica napus.

PubMed

Zhu, Lixia; Yang, Zonghui; Zeng, Xinhua; Gao, Jie; Liu, Jie; Yi, Bin; Ma, Chaozhi; Shen, Jinxiong; Tu, Jinxing; Fu, Tingdong; Wen, Jing

2017-04-01

We previously described a Brassica napus chlorophyll-deficient mutant (ygl) with yellow-green seedling leaves and mapped the related gene, BnaC.YGL, to a 0.35 cM region. However, the molecular mechanisms involved in this chlorophyll defect are still unknown. In this study, the BnaC07.HO1 gene (equivalent to BnaC.YGL) was isolated by the candidate gene approach, and its function was confirmed by genetic complementation. Comparative sequencing analysis suggested that BnaC07.HO1 was lost in the mutant, while a long noncoding-RNA was inserted into the promoter of the homologous gene BnaA07.HO1. This insert was widely present in B. napus cultivars and down-regulated BnaA07.HO1 expression. BnaC07.HO1 was highly expressed in the seedling leaves and encoded heme oxygenase 1, which was localized in the chloroplast. Biochemical analysis showed that BnaC07.HO1 can catalyze heme conversion to form biliverdin IXα. RNA-seq analysis revealed that the loss of BnaC07.HO1 impaired tetrapyrrole metabolism, especially chlorophyll biosynthesis. According, the levels of chlorophyll intermediates were reduced in the ygl mutant. In addition, gene expression in multiple pathways was affected in ygl. These findings provide molecular evidences for the basis of the yellow-green leaf phenotype and further insights into the crucial role of HO1 in B. napus.

Vasculoprotective effects of heme oxygenase-1 in a murine model of hyperoxia-induced bronchopulmonary dysplasia

PubMed Central

Fernandez-Gonzalez, Angeles; Alex Mitsialis, S.; Liu, Xianlan

2012-01-01

Bronchopulmonary dysplasia (BPD) is characterized by simplified alveolarization and arrested vascular development of the lung with associated evidence of endothelial dysfunction, inflammation, increased oxidative damage, and iron deposition. Heme oxygenase-1 (HO-1) has been reported to be protective in the pathogenesis of diseases of inflammatory and oxidative etiology. Because HO-1 is involved in the response to oxidative stress produced by hyperoxia and is critical for cellular heme and iron homeostasis, it could play a protective role in BPD. Therefore, we investigated the effect of HO-1 in hyperoxia-induced lung injury using a neonatal transgenic mouse model with constitutive lung-specific HO-1 overexpression. Hyperoxia triggered an increase in pulmonary inflammation, arterial remodeling, and right ventricular hypertrophy that was attenuated by HO-1 overexpression. In addition, hyperoxia led to pulmonary edema, hemosiderosis, and a decrease in blood vessel number, all of which were markedly improved in HO-1 overexpressing mice. The protective vascular response may be mediated at least in part by carbon monoxide, due to its anti-inflammatory, antiproliferative, and antiapoptotic properties. HO-1 overexpression, however, did not prevent alveolar simplification nor altered the levels of ferritin and lactoferrin, proteins involved in iron binding and transport. Thus the protective mechanisms elicited by HO-1 overexpression primarily preserve vascular growth and barrier function through iron-independent, antioxidant, and anti-inflammatory pathways. PMID:22287607

In vivo regulation of the heme oxygenase-1 gene in humanized transgenic mice

PubMed Central

Kim, Junghyun; Zarjou, Abolfazl; Traylor, Amie M.; Bolisetty, Subhashini; Jaimes, Edgar A.; Hull, Travis D.; George, James F.; Mikhail, Fady M.; Agarwal, Anupam

2012-01-01

Heme oxygenase-1 (HO-1) catalyzes the rate-limiting step in heme degradation producing equimolar amounts of carbon monoxide, iron, and biliverdin. Induction of HO-1 is a beneficial response to tissue injury in diverse animal models of diseases including acute kidney injury. In vitro analysis has shown that the human HO-1 gene is transcriptionally regulated by changes in chromatin conformation but whether such control occurs in vivo is not known. To enable such analysis, we generated transgenic mice, harboring an 87-kb bacterial artificial chromosome expressing human HO-1 mRNA and protein and bred these mice with HO-1 knockout mice to generate humanized BAC transgenic mice. This successfully rescued the phenotype of the knockout mice including reduced birth rates, tissue iron overload, splenomegaly, anemia, leukocytosis, dendritic cell abnormalities and survival after acute kidney injury induced by rhabdomyolysis or cisplatin nephrotoxicity. Transcription factors such as USF1/2, JunB, Sp1, and CTCF were found to associate with regulatory regions of the human HO-1 gene in the kidney following rhabdomyolysis. Chromosome Conformation Capture and ChIP-loop assays confirmed this in the formation of chromatin looping in vivo. Thus, these bacterial artificial chromosome humanized HO-1 mice are a valuable model to study the human HO-1 gene providing insight to the in vivo architecture of the gene in acute kidney injury and other diseases. PMID:22495295

High-pulse-energy 3.9-μm lasers in Ho:BYF

NASA Astrophysics Data System (ADS)

Stutz, Russell; Miller, Harold C.; Dinndorf, Kenneth M.; Cassanho, Arlete; Jenssen, Hans P.

2004-07-01

Experimental results describing pulsed lasers operating near 3.9 μm on the Ho3+ (5I5-5I6) transition in highly-doped (> 10 at. %) barium yttrium fluoride (BaY2F8 or BYF) will be presented. The 5I5 manifolds in Ho:BYF were pumped using a flashlamp excited, free-running Cr:LiSAF laser tuned to the Ho3+ absorption peak near 889nm. Ho3+ concentrations of 10%, 20%, 30% and 40% in BYF were lased in a simple end-pumped resonator. Some similar data was also obtained in 10% and 20% Ho:YLF. The highest 3.9 μm pulse energy obtained in the comparative study was 55 mJ (at ~10% optical-to-optical efficiency) using the 30% Ho:BYF crystal. A dual end-pumped laser in 30% Ho:BYF was also demonstrated, providing a pulse energy of 90 mJ in a near diffraction limited beam (M2 ~ 1.2). Emission decay data was taken to shed light on the observed dependence of laser efficiency on holmium concentration and excitation density. The lifetimes of both lasing levels (5I5 and 5I6) deviate rather significantly from their low-concentration values. Plausible energy transfer processes that may be responsible for the observed trends in the laser and emission data will also be discussed.

Mica Nanoparticle, STB-HO Eliminates the Human Breast Carcinoma Cells by Regulating the Interaction of Tumor with its Immune Microenvironment.

PubMed

Kang, Tae-Wook; Kim, Hyung-Sik; Lee, Byung-Chul; Shin, Tae-Hoon; Choi, Soon Won; Kim, Yoon-Jin; Lee, Hwa-Yong; Jung, Yeon-Kwon; Seo, Kwang-Won; Kang, Kyung-Sun

2015-12-03

Mica, an aluminosilicate mineral, has been proven to possess anti-tumor and immunostimulatory effects. However, its efficacy and mechanisms in treating various types of tumor are less verified and the mechanistic link between anti-tumor and immunostimulatory effects has not been elucidated. We sought to investigate the therapeutic effect of STB-HO (mica nanoparticles) against one of the most prevalent cancers, the breast cancer. STB-HO was orally administered into MCF-7 xenograft model or directly added to culture media and tumor growth was monitored. STB-HO administration exhibited significant suppressive effects on the growth of MCF-7 cells in vivo, whereas STB-HO did not affect the proliferation and apoptosis of MCF-7 cells in vitro. To address this discrepancy between in vivo and in vitro results, we investigated the effects of STB-HO treatment on the interaction of MCF-7 cells with macrophages, dendritic cells (DCs) and natural killer (NK) cells, which constitute the cellular composition of tumor microenvironment. Importantly, STB-HO not only increased the susceptibility of MCF-7 cells to immune cells, but also stimulated the immunocytes to eliminate cancer cells. In conclusion, our study highlights the possible role of STB-HO in the suppression of MCF-7 cell growth via the regulation of interactions between tumor cells and anti-tumor immune cells.

Mica Nanoparticle, STB-HO Eliminates the Human Breast Carcinoma Cells by Regulating the Interaction of Tumor with its Immune Microenvironment

PubMed Central

Kang, Tae-Wook; Kim, Hyung-Sik; Lee, Byung-Chul; Shin, Tae-Hoon; Choi, Soon Won; Kim, Yoon-Jin; Lee, Hwa-Yong; Jung, Yeon-Kwon; Seo, Kwang-Won; Kang, Kyung-Sun

2015-01-01

Mica, an aluminosilicate mineral, has been proven to possess anti-tumor and immunostimulatory effects. However, its efficacy and mechanisms in treating various types of tumor are less verified and the mechanistic link between anti-tumor and immunostimulatory effects has not been elucidated. We sought to investigate the therapeutic effect of STB-HO (mica nanoparticles) against one of the most prevalent cancers, the breast cancer. STB-HO was orally administered into MCF-7 xenograft model or directly added to culture media and tumor growth was monitored. STB-HO administration exhibited significant suppressive effects on the growth of MCF-7 cells in vivo, whereas STB-HO did not affect the proliferation and apoptosis of MCF-7 cells in vitro. To address this discrepancy between in vivo and in vitro results, we investigated the effects of STB-HO treatment on the interaction of MCF-7 cells with macrophages, dendritic cells (DCs) and natural killer (NK) cells, which constitute the cellular composition of tumor microenvironment. Importantly, STB-HO not only increased the susceptibility of MCF-7 cells to immune cells, but also stimulated the immunocytes to eliminate cancer cells. In conclusion, our study highlights the possible role of STB-HO in the suppression of MCF-7 cell growth via the regulation of interactions between tumor cells and anti-tumor immune cells. PMID:26631982

Hemeoxygenase-1 Mediates an Adaptive Response to Spermidine-Induced Cell Death in Human Endothelial Cells

PubMed Central

Yang, Hana; Lee, Seung Eun; Kim, Gun-Dong; Park, Hye Rim; Park, Yong Seek

2013-01-01

Spermidine (SPD) is a ubiquitous polycation that is commonly distributed in living organisms. Intracellular levels of SPD are tightly regulated, and SPD controls cell proliferation and death. However, SPD undergoes oxidation in the presence of serum, producing aldehydes, hydrogen peroxide, and ammonia, which exert cytotoxic effect on cells. Hemeoxygenase-1 (HO-1) is thought to have a protective effect against oxidative stress. Upregulation of HO-1 in endothelial cells is considered to be beneficial in the cardiovascular disease. In the present study, we demonstrate that the ubiquitous polyamine, SPD, induces HO-1 in human umbilical vein endothelial cells (HUVECs). SPD-induced HO-1 expression was examined by Western blot and reverse transcription-polymerase chain reaction (RT-PCR). Involvement of reactive oxygen species, serum amine oxidase, PI3K/Akt signaling pathway, and transcription factor Nrf2 in the induction of HO-1 by SPD was also investigated. Furthermore, small interfering RNA knockdown of Nrf2 or HO-1 and treatment with the specific HO-1 inhibitor ZnPP exhibited a noteworthy increase of death of SPD-stimulated HUVECs. In conclusion, these results suggest that SPD induces PI3K/Akt-Nrf2-mediated HO-1 expression in human endothelial cells, which may have a role in cytoprotection of the cells against oxidative stress-induced death. PMID:23983896

Vibrational non-equilibrium in the hydrogen-oxygen reaction. Comparison with experiment

NASA Astrophysics Data System (ADS)

Skrebkov, Oleg V.

2015-03-01

A theoretical model is proposed for the chemical and vibrational kinetics of hydrogen oxidation based on consistent accounting of the vibrational non-equilibrium of the HO2 radical that forms as a result of the bimolecular recombination H+O2 → HO2. In the proposed model, the chain branching H+O2 = O+OH and inhibiting H+O2+M = HO2+M formal reactions are treated (in the terms of elementary processes) as a single multi-channel process of forming, intramolecular energy redistribution between modes, relaxation, and unimolecular decay of the comparatively long-lived vibrationally excited HO2 radical, which is able to react and exchange energy with the other components of the mixture. The model takes into account the vibrational non-equilibrium of the starting (primary) H2 and O2 molecules, as well as the most important molecular intermediates HO2, OH, O2(1Δ), and the main reaction product H2O. It is shown that the hydrogen-oxygen reaction proceeds in the absence of vibrational equilibrium, and the vibrationally excited HO2(v) radical acts as a key intermediate in a fundamentally important chain branching process and in the generation of electronically excited species O2(1Δ), O(1D), and OH(2Σ+). The calculated results are compared with the shock tube experimental data for strongly diluted H2-O2 mixtures at 1000 < T < 2500 K, 0.5 < p < 4 atm. It is demonstrated that this approach is promising from the standpoint of reconciling the predictions of the theoretical model with experimental data obtained by different authors for various compositions and conditions using different methods. For T < 1500 K, the nature of the hydrogen-oxygen reaction is especially non-equilibrium, and the vibrational non-equilibrium of the HO2 radical is the essence of this process. The quantitative estimation of the vibrational relaxation characteristic time of the HO2 radical in its collisions with H2 molecules has been obtained as a result of the comparison of different experimental data on induction time measurements with the relevant calculations.

Expression and characterization of full-length human heme oxygenase-1: the presence of intact membrane-binding region leads to increased binding affinity for NADPH cytochrome P450 reductase.

PubMed

Huber, Warren J; Backes, Wayne L

2007-10-30

Heme oxygenase-1 (HO-1) is the chief regulatory enzyme in the oxidative degradation of heme to biliverdin. In the process of heme degradation, HO-1 receives the electrons necessary for catalysis from the flavoprotein NADPH cytochrome P450 reductase (CPR), releasing free iron and carbon monoxide. Much of the recent research involving heme oxygenase has been done using a 30 kDa soluble form of the enzyme, which lacks the membrane binding region (C-terminal 23 amino acids). The goal of this study was to express and purify a full-length human HO-1 (hHO-1) protein; however, due to the lability of the full-length form, a rapid purification procedure was required. This was accomplished by use of a glutathione-s-transferase (GST)-tagged hHO-1 construct. Although the procedure permitted the generation of a full-length HO-1, this form was contaminated with a 30 kDa degradation product that could not be eliminated. Therefore, attempts were made to remove a putative secondary thrombin cleavage site by a conservative mutation of amino acid 254, which replaces arginine with lysine. This mutation allowed the expression and purification of a full-length hHO-1 protein. Unlike wild type (WT) HO-1, the R254K mutant could be purified to a single 32 kDa protein capable of degrading heme at the same rate as the WT enzyme. The R254K full-length form had a specific activity of approximately 200-225 nmol of bilirubin h-1 nmol-1 HO-1 as compared to approximately 140-150 nmol of bilirubin h-1 nmol-1 for the WT form, which contains the 30 kDa contaminant. This is a 2-3-fold increase from the previously reported soluble 30 kDa HO-1, suggesting that the C-terminal 23 amino acids are essential for maximal catalytic activity. Because the membrane-spanning domain is present, the full-length hHO-1 has the potential to incorporate into phospholipid membranes, which can be reconstituted at known concentrations, in combination with other endoplasmic reticulum resident enzymes.

On the role of the termolecular reactions 2O2 + H2 → 2HO2 and 2O2 + H2 → H + HO2 + O2 in formation of the first radicals in hydrogen combustion: ab initio predictions of energy barriers.

PubMed

Monge-Palacios, M; Rafatijo, Homayoon

2017-01-18

We have investigated the role of termolecular reactions in the early chemistry of hydrogen combustion. We performed molecular chemical dynamics simulations using ReaxFF in LAMMPS to identify potential initial reactions for a 1 : 4 mixture of H 2  : O 2 in the NVT ensemble at density 276.3 kg m -3 and ∼3000 K (∼4000 atm) and ∼4000 K (∼5000 atm), and then characterized the saddle points for those reactions using ab initio methods: CCSD(T) = FC/cc-pVTZ//MP2/6-31G, CCSD(T) = FULL/aug-cc-pVTZ//CCSD = FC/cc-pVTZ and CASSCF MP2/6-31G//MP2/6-31G. The main initial reaction is H 2 + O 2 → H + HO 2 , frequently occurring in the presence of a second O 2 as a third body; that is, 2O 2 + H 2 → H + HO 2 + O 2 . The second most frequent reaction is 2O 2 + H 2 → 2HO 2 . We found three saddle points on the triplet PES of these termolecular reactions: one for 2O 2 + H 2 → H + HO 2 + O 2 and two for 2O 2 + H 2 → 2HO 2 . In the latter case, one has a symmetric structure consistent with simultaneous formation of two HO 2 and the other corresponds to a bimolecular reaction between O 2 and H 2 that is "interrupted" by a second O 2 before going to completion. The classical barrier height of the symmetric saddle point for 2O 2 + H 2 → 2HO 2 is 49.8 kcal mol -1 . The barrier to H 2 + O 2 → H + HO 2 is 58.9 kcal mol -1 . The termolecular reaction will be competitive with H 2 + O 2 → H + HO 2 only at sufficiently high pressures.

Beneficial use of serum ferritin and heme oxygenase-1 as biomarkers in adult-onset Still's disease: A multicenter retrospective study.

PubMed

Kirino, Yohei; Kawaguchi, Yasushi; Tada, Yoshifumi; Tsukamoto, Hiroshi; Ota, Toshiyuki; Iwamoto, Masahiro; Takahashi, Hiroki; Nagasawa, Kohei; Takei, Shuji; Horiuchi, Takahiko; Ichida, Hisae; Minota, Seiji; Ueda, Atsuhisa; Ohta, Akihide; Ishigatsubo, Yoshiaki

2018-01-11

Heme oxygenase (HO)-1 is a heme-degrading enzyme highly expressed in monocyte/macrophage, serum levels of which may be promising biomarker for adult-onset Still's disease (AOSD). We here report data on the use of serum ferritin and HO-1 levels in AOSD. Under the Hypercytokinemia Study Group collaboration, we collected sera from a total of 145 AOSD patients. Three independent experts judged whether the patients were definite AOSD depending on the clinical information. These 91 'definite AOSD' patients were further divided into active, remission, and relapse groups. Forty-six cases of systemic vasculitis, sepsis, etc. were included as disease controls. Serum ferritin and HO-1 levels were measured using ELISA. Associations between clinical symptoms, serum ferritin, and HO-1 were explored. Multivariate regression analysis was performed to identify independent variables associated with definite AOSD diagnosis. Serum ferritin and HO-1 levels were significantly higher in active and relapsed AOSD cases compared to disease controls, and were reduced by the treatment. Although a significant correlation was found between serum ferritin and HO-1 levels, a discrepancy was found in some cases such as iron-deficiency anemia. Receiver operating characteristic analysis identified optimal levels of serum ferritin (>819 ng/ml; sensitivity 76.1% and specificity 73.8%), and serum HO-1 (>30.2 ng/ml; sensitivity 84.8% and specificity 83.3%) that differentiated AOSD from controls. Interestingly, 88.9% of patients with AOSD who relapsed exceeded the cut-off value of serum HO-1 > 30.2 ng/ml, but only 50.0% exceeded serum ferritin >819 ng/ml (p = .013), suggesting that serum HO-1 levels may be a convenient indicator of AOSD disease status. Multivariate analysis identified neutrophilia, RF/ANA negativity, sore throat, and elevated serum HO-1 as independent variables associated with AOSD diagnosis. We confirmed that serum ferritin and HO-1 serve as highly specific and sensitive biomarkers for AOSD. A future prospective study with large sample size is necessary to determine whether these biomarkers could be included in Yamaguchi's Criteria.

Augmented-reality-based skills training for robot-assisted urethrovesical anastomosis: a multi-institutional randomised controlled trial.

PubMed

Chowriappa, Ashirwad; Raza, Syed Johar; Fazili, Anees; Field, Erinn; Malito, Chelsea; Samarasekera, Dinesh; Shi, Yi; Ahmed, Kamran; Wilding, Gregory; Kaouk, Jihad; Eun, Daniel D; Ghazi, Ahmed; Peabody, James O; Kesavadas, Thenkurussi; Mohler, James L; Guru, Khurshid A

2015-02-01

To validate robot-assisted surgery skills acquisition using an augmented reality (AR)-based module for urethrovesical anastomosis (UVA). Participants at three institutions were randomised to a Hands-on Surgical Training (HoST) technology group or a control group. The HoST group was given procedure-based training for UVA within the haptic-enabled AR-based HoST environment. The control group did not receive any training. After completing the task, the control group was offered to cross over to the HoST group (cross-over group). A questionnaire administered after HoST determined the feasibility and acceptability of the technology. Performance of UVA using an inanimate model on the daVinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) was assessed using a UVA evaluation score and a Global Evaluative Assessment of Robotic Skills (GEARS) score. Participants completed the National Aeronautics and Space Administration Task Load Index (NASA TLX) questionnaire for cognitive assessment, as outcome measures. A Wilcoxon rank-sum test was used to compare outcomes among the groups (HoST group vs control group and control group vs cross-over group). A total of 52 individuals participated in the study. UVA evaluation scores showed significant differences in needle driving (3.0 vs 2.3; P = 0.042), needle positioning (3.0 vs 2.4; P = 0.033) and suture placement (3.4 vs 2.6; P = 0.014) in the HoST vs the control group. The HoST group obtained significantly higher scores (14.4 vs 11.9; P 0.012) on the GEARS. The NASA TLX indicated lower temporal demand and effort in the HoST group (5.9 vs 9.3; P = 0.001 and 5.8 vs 11.9; P = 0.035, respectively). In all, 70% of participants found that HoST was similar to the real surgical procedure, and 75% believed that HoST could improve confidence for carrying out the real intervention. Training in UVA in an AR environment improves technical skill acquisition with minimal cognitive demand. © 2014 The Authors. BJU International © 2014 BJU International.

Synthesis of ferrite and nickel ferrite nanoparticles using radio-frequency thermal plasma torch

NASA Astrophysics Data System (ADS)

Son, S.; Taheri, M.; Carpenter, E.; Harris, V. G.; McHenry, M. E.

2002-05-01

Nanocrystalline (NC) ferrite powders have been synthesized using a 50 kW-3 MHz rf thermal plasma torch for high-frequency soft magnet applications. A mixed powder of Ni and Fe (Ni:Fe=1:2), a NiFe permalloy powder with additional Fe powder (Ni:Fe=1:2), and a NiFe permalloy powder (Ni:Fe=1:1) were used as precursors for synthesis. Airflow into the reactor chamber was the source of oxygen for oxide formation. XRD patterns clearly show that the precursor powders were transformed into NC ferrite particles with an average particle size of 20-30 nm. SEM and TEM studies indicated that NC ferrite particles had well-defined polygonal growth forms with some exhibiting (111) faceting and many with truncated octahedral and truncated cubic shapes. The Ni content in the ferrite particles was observed to increase in going from mixed Ni and Fe to mixed permalloy and iron and finally to only permalloy starting precursor. The plasma-torch synthesized ferrite materials using exclusively the NiFe permalloy precursor had 40%-48% Ni content in the Ni-ferrite particle, differing from the NiFe2O4 ideal stoichiometry. EXAFS was used to probe the cation coordination in low Ni magnetite species. The coercivity and Neel temperature of the high Ni content ferrite sample were 58 Oe and ˜590 °C, respectively.

[Sources and potential risk of heavy metals in roadside soils of Xi' an City].

PubMed

Chen, Jing-hui; Lu, Xin-wei; Zhai, Meng

2011-07-01

Based on the X-Ray fluorescence spectroscopic measurement of heavy metals concentration in roadside soil samples from Xi' an City, and by the methods of principal component analysis, cluster analysis, and correlation analysis, this paper approached the possible sources of heavy metals in the roadside soils of the City. In the meantime, potential ecological risk index was used to assess the ecological risk of the heavy metals. In the roadside soils, the mean concentrations of Co, Cr, Cu, Mn, Ni, Pb, and Zn were higher than those of the Shaanxi soil background values. The As, Mn and Ni in roadside soils mainly came from natural source and transportation source, the Cu, Pb, and Zn mainly came from transportation source, and the Co and Cr mainly came from industry source. These heavy metals in the roadside soils belonged to medium pollution, and had medium potential ecological risk.

Temperature effect on betavoltaic microbatteries based on Si and GaAs under 63Ni and 147Pm irradiation

NASA Astrophysics Data System (ADS)

Wang, Hao; Tang, Xiao-bin; Liu, Yun-Peng; Xu, Zhi-Heng; Liu, Min; Chen, Da

2015-09-01

The effect of temperature on the output performance of four different types of betavoltaic microbatteries was investigated experimental and theoretical. Si and GaAs were selected as the energy conversion devices in four types of betavoltaic microbatteries, and 63Ni and 147Pm were used as beta sources. Current density-voltage curves were determined at a temperature range of 213.15-333.15 K. A simplified method was used to calculate the theoretical parameters of the betavoltaic microbatteries considering the energy loss of beta particles for self-absorption of radioactive source, the electron backscatter effect of different types of semiconductor materials, and the absorption of dead layer. Both the experimental and theoretical results show that the short-circuit current density increases slightly and the open-circuit voltage (VOC) decreases evidently with the increase in temperature. Different combinations of energy conversion devices and beta sources cause different effects of temperature on the microbatteries. In the approximately linear range, the VOC sensitivities caused by temperature for 63Ni-Si, 63Ni-GaAs, 147Pm-Si, and 147Pm-GaAs betavoltaic microbatteries were -2.57, -5.30, -2.53, and -4.90 mV/K respectively. Both theoretical and experimental energy conversion efficiency decreased evidently with the increase in temperature.

Ge-on-insulator tunneling FET with abrupt source junction formed by utilizing snowplow effect of NiGe

NASA Astrophysics Data System (ADS)

Matsumura, Ryo; Katoh, Takumi; Takaguchi, Ryotaro; Takenaka, Mitsuru; Takagi, Shinichi

2018-04-01

Tunneling field-effect transistors (TFETs) attract much attention for use in realizing next-generation low-power processors. In particular, Ge-on-insulator (GOI) TFETs are expected to realize low power operation with a high on-current/off-current (I on/I off) ratio, owing to their narrow bandgap. Here, to improve the performance of GOI-TFETs, a source junction with a high doping concentration and an abrupt impurity profile is essential. In this study, a snowplow effect of NiGe combined with low-energy BF2 + implantation has been investigated to realize an abrupt p+/n Ge junction for GOI n-channel TFETs. By optimizing the Ni thickness to form NiGe (thickness: 4 nm), an abrupt junction with a B profile abruptness of ˜5 nm/dec has been realized with a high doping concentration of around 1021 cm-3. The operation of GOI n-TFETs with this source junction having the abrupt B profile has been demonstrated, and the improvement of TFET properties such as the I on/I off ratio from 311 to 743 and the subthreshold slope from 368 to 239 mV/dec has been observed. This junction formation technology is attractive for enhancing the TFET performance.

Electro-oxidation of methanol in alkaline conditions using Pd-Ni nanoparticles prepared from organometallic precursors and supported on carbon vulcan

NASA Astrophysics Data System (ADS)

Manzo-Robledo, A.; Costa, Natália J. S.; Philippot, K.; Rossi, Liane M.; Ramírez-Meneses, E.; Guerrero-Ortega, L. P. A.; Ezquerra-Quiroga, S.

2015-12-01

Oxidation of low-molecular weight alcohols as energy sources using metal nanoparticles has attracted considerable interest for use as a power source in portable electronic devices. In this work, a series of mono- and bimetallic nanoparticles based on palladium and nickel (Pd, Pd90Ni10, Pd50Ni50, Pd10Ni90, and Ni) have been synthesized from organometallic precursors, namely tris(dibenzylideneacetone) dipalladium(0), Pd2(dba)3, and bis(1,5-cyclooctadiene)nickel(0), Ni(cod)2. Well-defined metal particles in the nanometric scale from 4.2 to 6.3 nm were observed by transmission electron microscopy. The as-prepared nanoparticles were mixed with a carbon Vulcan matrix (10 % wt. of the catalyst in turn) for investigation as electrocatalysts in methanol oxidation reaction (MOR) in alkaline conditions. The i- E profiles from cyclic voltammetry for the monometallic systems indicated a redox process attributed only to palladium or nickel, as expected. With the bimetallic nanomaterials, the redox process and the i- E characteristics are functions of the amount of nickel associated to palladium. From a fundamental point of view, it has been established that the OH ions' interfacial interaction and the MOR kinetics are affected by the presence of nickel (decreasing the faradic current) as supported by the current versus potential profiles obtained as a function of methanol concentration and with temperature variation.

Heavy metals pollution and pb isotopic signatures in surface sediments collected from Bohai Bay, North China.

PubMed

Gao, Bo; Lu, Jin; Hao, Hong; Yin, Shuhua; Yu, Xiao; Wang, Qiwen; Sun, Ke

2014-01-01

To investigate the characteristics and potential sources of heavy metals pollution, surface sediments collected from Bohai Bay, North China, were analyzed for the selected metals (Cd, Cr, Cu, Ni, Pb, and Zn). The Geoaccumulation Index was used to assess the level of heavy metal pollution. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. The results showed that the average concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were 0.15, 79.73, 28.70, 36.56, 25.63, and 72.83 mg/kg, respectively. The mean concentrations of the studied metals were slightly higher than the background values. However, the heavy metals concentrations in surface sediments in Bohai Bay were below the other important bays or estuaries in China. The assessment by Geoaccumulation Index indicated that Cr, Zn, and Cd were classified as "the unpolluted" level, while Ni, Cu, and Pb were ranked as "unpolluted to moderately polluted" level. The order of pollution level of heavy metals was: Pb > Ni > Cu > Cr > Zn > Cd. The Pb isotopic ratios in surface sediments varied from 1.159 to 1.185 for (206)Pb/(207)Pb and from 2.456 to 2.482 for (208)Pb/(207)Pb. Compared with Pb isotopic radios in other sources, Pb contaminations in the surface sediments of Bohai Bay may be controlled by the mix process of coal combustion, aerosol particles deposition, and natural sources.