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Sample records for da zeolita hzsm5

  1. In situ DRIFTS investigation for the oxidation of toluene by ozone over Mn/HZSM-5, Ag/HZSM-5 and Mn-Ag/HZSM-5 catalysts

    NASA Astrophysics Data System (ADS)

    Li, Jiao; Na, Hongbo; Zeng, Xiaolan; Zhu, Tianle; Liu, Zhiming

    2014-08-01

    The mechanism of toluene oxidation at room temperature over Mn/HZSM-5, Ag/HZSM-5 and Mn-Ag/HZSM-5 catalysts was investigated by in situ DRIFTS. The results show that only a little toluene can be partially oxidized into benzyl alcohol in the absence of O3, while it can be further oxidized into benzaldehyde, benzoic acid, maleic anhydride, and ultimately mineralized to CO2 in the presence of O3. The lattice oxygen is the oxygen species of oxidizing toluene into benzyl alcohol, and the active oxygen species generated from ozone decomposition on the oxygen vacancy over the catalysts are responsible for its complete oxidation. Compared with Mn/HZSM-5 and Ag/HZSM-5 catalysts, the Mn-Ag/HZSM-5 catalyst shows higher catalytic activity for toluene oxidation by ozone, which is attributed to more oxygen vacancy in this catalyst, based on the XPS characterization results.

  2. Furan production from glycoaldehyde over HZSM-5

    DOE PAGESBeta

    Kim, Seonah; Evans, Tabitha J.; Mukarakate, Calvin; Bu, Lintao; Beckham, Gregg T.; Nimlos, Mark R.; Paton, Robert S.; Robichaud, David J.

    2016-04-03

    Catalytic fast pyrolysis of biomass over zeolite catalysts results primarily in aromatic (e.g. benzene, toluene, xylene) and olefin products. However, furans are a higher value intermediate for their ability to be readily transformed into gasoline, diesel, and chemicals. Here we investigate possible mechanisms for the coupling of glycoaldehyde, a common product of cellulose pyrolysis, over HZSM-5 for the formation of furans. Experimental measurements of neat glycoaldehyde over a fixed bed of HZSM-5 confirm furans (e.g. furanone) are products of this reaction at temperatures below 300 degrees C with several aldol condensation products as co-products (e.g. benzoquinone). However, under typical catalyticmore » fast pyrolysis conditions (>400 degrees C), further reactions occur that lead to the usual aromatic product slate. ONIOM calculations were utilized to identify the pathway for glycoaldehyde coupling toward furanone and hydroxyfuranone products with dehydration reactions serving as the rate determining steps with typical intrinsic reaction barriers of 40 kcal mol-1. The reaction mechanisms for glycoaldehyde will likely be similar to that of other small oxygenates such as acetaldehyde, lactaldehyde, and hydroxyacetone and this study provides a generalizable mechanism of oxygenate coupling and furan formation over zeolite catalysts.« less

  3. Conversion of Ethanol to Hydrocarbons on Hierarchical HZSM-5 Zeolites

    SciTech Connect

    Ramasamy, Karthikeyan K.; Zhang, He; Sun, Junming; Wang, Yong

    2014-02-22

    This study reports synthesis, characterization, and catalytic activity of the nano-size hierarchical HZSM-5 zeolite with high mesoporosity produced via a solvent evaporation procedure. Further, this study compares hierarchical zeolites with conventional HZSM-5 zeolite with similar Si/Al ratios for the ethanol-to-hydrocarbon conversion process. The catalytic performance of the hierarchical and conventional zeolites was evaluated using a fixed-bed reactor at 360 °C, 300 psig, and a weight hourly space velocity of 7.9 h-1. For the low Si/Al ratio zeolite (~40), the catalytic life-time for the hierarchical HZSM-5 was approximately 2 times greater than the conventional HZSM-5 despite its coking amount deposited 1.6 times higher than conventional HZSM-5. For the high Si/Al ratio zeolite (~140), the catalytic life-time for the hierarchical zeolite was approximately 5 times greater than the conventional zeolite and the amount of coking deposited was 2.1 times higher. Correlation was observed between catalyst life time, porosity, and the crystal size of the zeolite. The nano-size hierarchical HZSM-5 zeolites containing mesoporosity demonstrated improved catalyst life-time compared to the conventional catalyst due to faster removal of products, shorter diffusion path length, and the migration of the coke deposits to the external surface from the pore structure.

  4. Biodiesel production by free fatty acid esterification using Lanthanum (La3+) and HZSM-5 based catalysts.

    PubMed

    Vieira, Sara S; Magriotis, Zuy M; Santos, Nadiene A V; Saczk, Adelir A; Hori, Carla E; Arroyo, Pedro A

    2013-04-01

    In this work the use of the heterogeneous catalysts pure (LO) and sulfated (SLO) lanthanum oxide, pure HZSM-5 and SLO/HZSM-5 (HZSM-5 impregnated with sulfated lanthanum oxide (SO4(2-)/La2O3)) was evaluated. The structural characterization of the materials (BET) showed that the sulfation process led to a reduction of the SLO and SLO/HZSM-5 surface area values. FTIR showed bands characteristic of the materials and, FTIR-pyridine indicated the presence of strong Brønsted sites on the sulfated material. In the catalytic tests the temperature was the parameter that most influenced the reactions. The best reaction conditions were: 10% catalyst, 100°C temperature and 1:5 m(OA)/m(meOH) for LO, SLO, SLO/HZSM-5 and 10% catalyst, 100°C temperature and 1:20 m(OA)/m(meOH) for HZSM-5. Under these conditions the conversions were: 67% and 96%, for LO and SLO, respectively and 80% and 100%, for HZSM-5 and SLO/HZSM-5, respectively. All catalysts deactivated after the first use, but the deactivation of SLO/HZSM-5 was smaller. PMID:23428822

  5. Hydrothermal liquefaction of Chlorella pyrenoidosa for bio-oil production over Ce/HZSM-5.

    PubMed

    Xu, Yufu; Zheng, Xiaojing; Yu, Huiqiang; Hu, Xianguo

    2014-03-01

    This paper investigated a novel hydrothermal liquefaction process of Chlorella pyrenoidosa catalyzed by Ce/HZSM-5. The chemical groups and components of the residues of C. pyrenoidosa were analyzed by Fourier transform infrared spectrometry and Gas Chromatograph-Mass Spectrometer. The crystal structure and micro surface topography of C. pyrenoidosa before and after catalytic liquefaction were characterized by X-ray diffraction and Scanning electron microscopy, respectively. The experimental results showed that the catalytic cracking effects of Ce/HZSM-5 were superior to that of HZSM-5 as a liquefaction catalyst of C. pyrenoidosa. Compared with HZSM-5, Ce/HZSM-5 has a significantly enhanced Lewis acid active center, smaller particle size, larger specific surface, and highly dispersed Ce4O7 with trivalent and tetravalent cerium in the zeolite skeleton channel that accelerate the catalytic liquefaction of C. pyrenoidosa. The rare earth modified zeolite Ce/HZSM-5 exhibits good potential and a beneficial nature for the preparation of bio-oil from microalgae with high efficiency. PMID:24472700

  6. Removal of gas phase low-concentration toluene over Mn, Ag and Ce modified HZSM-5 catalysts by periodical operation of adsorption and non-thermal plasma regeneration.

    PubMed

    Wang, Wenzheng; Wang, Honglei; Zhu, Tianle; Fan, Xing

    2015-07-15

    Ag/HZSM-5, Mn/HZSM-5, Ce/HZSM-5, Ag-Mn/HZSM-5 and Ce-Mn/HZSM-5 were prepared by impregnation method. Both their adsorption capacity and catalytic activity were investigated for the removal of gas phase low-concentration toluene by periodical operation of adsorption and non-thermal plasma regeneration. Results show that catalysts loaded with Ag (Ag/HZSM-5 and Ag-Mn/HZSM-5) had larger adsorption capacity for toluene than the other catalysts. And Ag-Mn/HZSM-5 displayed the best catalytic performance for both toluene oxidation by non-thermal plasma and byproducts suppression. On the other hand, the deactivated catalyst can be fully regenerated by calcining in air stream when its adsorption capacity and catalytic activity of the Ag-Mn/HZSM-5 catalyst was found to be decreased after 10 cycles of periodical adsorption and non-thermal regeneration. PMID:25795275

  7. Production of aromatic hydrocarbons via catalytic pyrolysis of biomass over fe-modified HZSM-5 zeolites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Iron modified HZSM-5 catalysts were prepared by partial ion exchange of NH4ZSM-5 with Fe (II) at three different loadings (1.4, 2.8 and 4.2 wt%), and their effectiveness for producing aromatic hydrocarbons from cellulose, cellobiose, lignin and switchgrass by catalytic pyrolysis were screened using ...

  8. Accumulation of inorganic impurities on HZSM-5 during catalytic fast pyrolysis of switchgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of inorganic species present in switchgrass during fluidized bed catalytic pyrolysis over HZSM-5 catalysts was studied with emphasis on their accumulation on the catalyst. Five catalytic pyrolysis experiments were performed in two series, reusing the catalyst after each sample. Catalysts w...

  9. Direct Conversion of Syngas-to-Hydrocarbons over Higher Alcohols Synthesis Catalysts Mixed with HZSM-5

    SciTech Connect

    Lebarbier Dagel, Vanessa M.; Dagle, Robert A.; Li, Jinjing; Deshmane, Chinmay A.; Taylor, Charles E.; Bao, Xinhe; Wang, Yong

    2014-09-10

    The synthesis of hydrocarbon fuels directly from synthesis gas (i.e. one step process) was investigated with a catalytic system comprised of HZSM-5 physically mixed with either a methanol synthesis catalyst or a higher alcohols synthesis (HAS) catalyst. The metal sites of the methanol or HAS synthesis catalyst enable the conversion of syngas to alcohols, whereas HZSM-5 provides acid sites required for methanol dehydration, and dimethyl ether-to-hydrocarbons reactions. Catalytic performance for HZSM-5 when mixed with either a 5 wt.% Pd/ZnO/Al2O3 methanol synthesis catalyst or a HAS catalyst was evaluated at 300°C, 70 bars, GHSV=700 h-1 and H2/CO=1 using a HZSM-5: alcohols synthesis catalyst weight ratio of 3:1. The major difference observed between the methanol synthesis and HAS catalyst mixtures was found in the production of durene which is an undesirable byproduct. While durene formation is negligible with any of the HAS catalysts mixed with the HZSM-5 evaluated in this study, it represents almost 50% of the C5+ fraction for the methanol synthesis catalyst (5 wt.% Pd/ZnO/Al2O3 ) mixed with HZSM-5. This presents an advantage for using HAS catalysts over the methanol synthesis catalyst to minimize the durene by-product. The yield toward the desired C5+ hydrocarbons is thus twice higher with selected HAS catalysts as compared to when HZSM-5 is mixed with 5 wt.% Pd/ZnO/Al2O3. Among all the HAS catalysts evaluated in this study, a catalyst with 0.5 wt.% Pd/FeCoCu catalyst was found the most promising due to higher production of C5+ hydrocarbons and low durene formation. The efficiency of the one-step process was thus further evaluated using the HZSM-5: 0.5 wt.% Pd/FeCoCu catalyst mixture under a number of process conditions to maximize liquid hydrocarbons product yield. At 300oC, 70 bars, GHSV = 700 h-1 and HZSM-5: 0.5 wt.% Pd/FeCoCu = 3:1 (wt.), the C5+ fraction represents 48.5% of the hydrocarbons. Unfortunately, it is more difficult to achieve higher selectivity

  10. Catalysis at the toulene/water interface: Octadecyl immobilized H-ZSM-5 catalyst promoted hydrolysis of water-insoluble esters

    SciTech Connect

    Ogawa, Haruo; Koh, Tensai ); Taya, Kazuo ); Chihara, Teiji , Wako )

    1994-08-01

    Octadecyltrichorosilane-treated H-ZSM-5, abbreviated as H-ZSM-5-C[sub 18] resulted in an effective catalyst for the hydrolysis of water-insoluble esters in toluene-water solvent system. These floated at the interface of the two liquids. The H-ZSM-5-C[sub 18] catalyst showed ca. 60 times the activity of H-ZSM-5 for the hydrolysis of dodecyl acetate. Acid strength of H-ZSM-5 in water (-5.6 < Ho [<=] -3.0) was maintained even after the treatment with octadecyltrichlorosilane. The treatment renders H-ZSM-5 lipophylicity and provides a quasi-lipid phase on the surface. The shape-selective properties of H-ZSM-5-C[sub 18] catalyst were observed for the hydrolysis of aliphatic esters with straight chains. 17 refs., 9 figs., 6 tabs.

  11. Titania-supported bimetallic catalysts combined with HZSM-5 for Fischer-Tropsch synthesis

    SciTech Connect

    Jothimurugesan, K.; Gangwal, S.K.

    1998-04-01

    The Fischer-Tropsch synthesis (FTS) can convert coal or natural gas derived synthesis gas (CO + H{sub 2}) to liquid fuels and high-value chemicals. Fischer-Tropsch synthesis was studied in a fixed-bed reactor over single-metal and bimetallic alloy catalysts, selected from Co, Ni, and Fe, supported on TiO{sub 2} at a total metal loading of 10 wt%. The catalysts, prepared by incipient wetness impregnation using nitrate precursors, were tested as is and in combination with a HZSM-5 zeolite. The test conditions were 1 MPa, 250 C, H{sub 2}/CO = 1, and weight hourly space velocity (WHSV) = 0.77 h{sup {minus}1}. Alloying of metals resulted in a significant enhancement in CO conversion without an increase in methane selectivity. A 50:50 weight ratio Co-Ni catalyst physically mixed with HZSM-5 (5% Co-5% Ni/TiO{sub 2} + HZSM-5) gave the highest CO conversion (45.2%) at the conditions tested. This compares to conversion of 8.9% and 10.5% with Co-only and Ni-only catalysts, respectively. Mixing the Co-Ni catalyst with HZSM-5 resulted in a significant reduction in methane selectivity and a significant increase in C{sub 4}{sup +} selectivity. The aromatic fraction increased from 1.5 to 8.1 wt%, the C{sub 2}{sup +} olefins were nearly eliminated, and i-C{sub 4}H{sub 10} increased from 2.3 to 58.5 wt % in the C{sub 4} fraction.

  12. Tailoring acidity of HZSM-5 nanoparticles for methyl bromide dehydrobromination by Al and Mg incorporation

    PubMed Central

    2014-01-01

    Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR or Py-FTIR). It was found that the intensity of Lewis acid sites with weak strength was enhanced by impregnating MgO or reducing Al concentration, and such an enhancement could be explained by the formation of Mg(OH)+ or charge unbalance of the MgO framework on the surface of HZSM-5 support. The effect of HZSM-5 nanoparticles' acidity on methyl bromide dehydrobromination as catalyst was evaluated. As the results, MgHZ-360 catalyst with the highest concentration of Lewis acid sites showed excellent stability, which maintained methyl bromide conversion of up 97% in a period of 400 h on stream. Coke characterization by BET measurements and TGA/DTA and GC/MS analysis revealed that polymethylated naphthalenes species were formed outside the channels of the catalyst with higher acid intensity and higher Brønsted acid concentration during the initial period of reaction, while graphitic carbon formed in the channels of catalyst with lower acid intensity and higher Lewis acid concentration during the stable stage. PMID:25328502

  13. Tailoring acidity of HZSM-5 nanoparticles for methyl bromide dehydrobromination by Al and Mg incorporation.

    PubMed

    Liu, Zhen; Zhang, Zhongdong; Xing, Wei; Komarneni, Sridhar; Yan, Zifeng; Gao, Xionghou; Zhou, Xiaoping

    2014-01-01

    Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR or Py-FTIR). It was found that the intensity of Lewis acid sites with weak strength was enhanced by impregnating MgO or reducing Al concentration, and such an enhancement could be explained by the formation of Mg(OH)(+) or charge unbalance of the MgO framework on the surface of HZSM-5 support. The effect of HZSM-5 nanoparticles' acidity on methyl bromide dehydrobromination as catalyst was evaluated. As the results, MgHZ-360 catalyst with the highest concentration of Lewis acid sites showed excellent stability, which maintained methyl bromide conversion of up 97% in a period of 400 h on stream. Coke characterization by BET measurements and TGA/DTA and GC/MS analysis revealed that polymethylated naphthalenes species were formed outside the channels of the catalyst with higher acid intensity and higher Brønsted acid concentration during the initial period of reaction, while graphitic carbon formed in the channels of catalyst with lower acid intensity and higher Lewis acid concentration during the stable stage. PMID:25328502

  14. n-Hexane hydro-isomerization over promoted Pd/HZSM-5 catalysts

    NASA Astrophysics Data System (ADS)

    Thoa Dao, Thi Kim; Loc Luu, Cam

    2015-09-01

    A series of Pd/HZSM-5 catalysts modified by various metallic species, including Co, Ni, Fe, Re, and Cu, was prepared by sequential impregnation. Contents of Pd and second metals in modified catalysts were 0.8 and 1.0 wt%, respectively. Physico-chemical characteristics of catalysts were investigated by nitrogen physi-sorption (BET), x-ray diffraction (XRD), transmission electron microscopy (TEM), ammonia temperature programmed desorption (NH3-TPD), temperature programmed reduction (TPR) and hydrogen pulse chemisorption (HPC). Coke formation was studied by the method of thermogravimetric analysis (TGA). The activities of catalysts in n-hexane isomerization were studied in a micro-flow reactor under atmospheric pressure at 250 °C, and molar ratio of H2: n-hexane of 5.92. It was found that Co, Ni, Fe, and Re additives exhibited geometric and electronic effects toward Pd/HZSM-5 catalyst, leading to an enhancement of its activity and stability. On the contrary, Cu additive caused Pd/HZSM-5 to become poorer in activity and stability.

  15. Defect sites in highly siliceous HZSM-5 zeolites: A study performed by alumination and IR spectroscopy

    SciTech Connect

    Yamagishi, Kouji; Namba, Seitaro; Yashima, Tatsuaki )

    1991-01-24

    The concentration of oxygen atoms on defect sites in a highly siliceous HZSM-5 type zeolite was estimated by the {sup 18}O-exchange reaction between C{sup 18}O{sub 2} and the zeolite. The concentration of oxygen atoms on defect sites could be controlled by means of changes of the gel composition and of the use of various silica sources in the hydrothermal synthesis. The relationship between the concentration of oxygen atoms on defect sites in a highly siliceous HZSM-5 and the concentration of aluminum introduced into the framework of the HZSM-5 by an alumination was examined. The concentration of the framework aluminum was the same as one-fourth that of the oxygen atoms on defect sites. These results suggest that the defect sites into which aluminum atoms are introduced tetrahedrally can be identified with hydroxyl nests that consist of four silanol groups. The existence of hydroxyl nests could be confirmed by IR spectroscopy. From the {sup 18}O-exchange reaction and IR measurements, the authors conclude that the sharp band at 3,740 cm{sup {minus}1} can be attributed to both isolated SiOH groups on the external surface and intracrystalline isolated SiOH groups and that the broad band at 3,505 cm{sup {minus}1} can be attributed to the SiOH groups in hydroxyl nests.

  16. Hydrogen Production by Low-temperature Steam Reforming of Bio-oil over Ni/HZSM-5 Catalyst

    NASA Astrophysics Data System (ADS)

    Qiu, Song-bai; Gong, Lu; Liu, Lu; Hong, Cheng-gui; Yuan, Li-xia; Li, Quan-xin

    2011-04-01

    We investigated high catalytic activity of Ni/HZSM-5 catalysts synthesized by the impregnation method, which was successfully applied for low-temperature steam reforming of bio-oil. The influences of the catalyst composition, reforming temperature and the molar ratio of steam to carbon fed on the stream reforming process of bio-oil over the Ni/HZSM-5 catalysts were investigated in the reforming reactor. The promoting effects of current passing through the catalyst on the bio-oil reforming were also studied using the electrochemical catalytic reforming approach. By comparing Ni/HZSM-5 with commonly used Ni/Al2O3 catalysts, the Ni20/ZSM catalyst with Ni-loading content of about 20% on the HZSM-5 support showed the highest catalytic activity. Even at 450 °C, the hydrogen yield of about 90% with a near complete conversion of bio-oil was obtained using the Ni20/ZSM catalyst. It was found that the performance of the bio-oil reforming was remarkably enhanced by the HZSM-5 supporter and the current through the catalyst. The features of the Ni/HZSM-5 catalysts were also investigated via X-ray diffraction, inductively coupled plasma and atomic emission spectroscopy, hydrogen temperature-programmed reduction, and Brunauer-Emmett-Teller methods.

  17. Ozone-assisted photocatalytic oxidation of gaseous acetaldehyde on TiO2/H-ZSM-5 catalysts.

    PubMed

    Huang, Xin; Yuan, Jian; Shi, Jianwei; Shangguan, Wenfeng

    2009-11-15

    TiO(2)/H-ZSM-5 catalysts were prepared by impregnation with different amount of TiO(2) loading and calcination at various temperatures. The catalysts were characterized by X-ray diffraction (XRD), ultraviolet and visible spectroscopy (UV-vis) and BET specific surface area. It was demonstrated that the anatase TiO(2) retained stable on H-ZSM-5 after heat treatment even at 700 degrees C. The activities of samples were investigated under the various conditions of UV, ozone and UV-ozone, respectively by the comparison of acetaldehyde degradation. It was found that the photocatalysis combined with ozonation promoted the acetaldehyde degradation. TiO(2)/H-ZSM-5 catalysts were superior to simple TiO(2) and H-ZSM-5 with respect to the ozone-assisted photocatalytic oxidation of gaseous acetaldehyde, and the activity of the catalyst TiO(2)/H-ZSM-5 (TiO(2):H-ZSM-5=2:10) is the highest one among all those prepared samples. The improvement was attributed to the synergetic effect among adsorption, ozonation and catalytic reaction. PMID:19604630

  18. Methanol and ethanol conversion into hydrocarbons over H-ZSM-5 catalyst

    NASA Astrophysics Data System (ADS)

    Hamieh, S.; Canaff, C.; Tayeb, K. Ben; Tarighi, M.; Maury, S.; Vezin, H.; Pouilloux, Y.; Pinard, L.

    2015-07-01

    Ethanol and methanol are converted using H-ZSM-5 zeolite at 623 K and 3.0 MPa into identical hydrocarbons (paraffins, olefins and aromatics) and moreover with identical selectivities. The distribution of olefins as paraffins follows the Flory distribution with a growth probability of 0.53. Regardless of the alcohol, the catalyst lifetime and selectivity into hydrocarbons C3+ are high in spite of an important coke content. The coke that poisons the Brønsted acid sites without blocking their access is composed in part of radical polyalkylaromatics. The addition of hydroquinone, an inhibitor of radicals, to the feed, provokes an immediate catalyst deactivation.

  19. Conversion of Biomass-Derived Small Oxygenates over HZSM-5 and its Deactivation Mechanism

    SciTech Connect

    Ramasamy, Karthikeyan K.; Gerber, Mark A.; Flake, Matthew D.; Zhang, He; Wang, Yong

    2014-02-28

    HZSM-5 catalyst deactivation was studied using aqueous feed mixtures containing ethanol, ethanol+ acetic acid, ethanol+ethyl acetate, or ethanol+acetaldehyde in a fixed bed reactor at 360°C and 300psig. Compared to ethanol alone experiment, addition of other oxygenates reduced catalyst life in the order of: ethyl acetateHZSM-5 catalyst.

  20. Influence of Alumina Binder Content on Catalytic Performance of Ni/HZSM-5 for Hydrodeoxygenation of Cyclohexanone

    PubMed Central

    Kong, Xiangjin; Liu, Junhai

    2014-01-01

    The influence of the amount of alumina binders on the catalytic performance of Ni/HZSM-5 for hydrodeoxygenation of cyclohexanone was investigated in a fixed-bed reactor. N2 sorption, X-ray diffraction, H2-chemisorption and temperature-programmed desorption of ammonia were used to characterize the catalysts. It can be observed that the Ni/HZSM-5 catalyst bound with 30 wt.% alumina binder exhibited the best catalytic performance. The high catalytic performance may be due to relatively good Ni metal dispersion, moderate mesoporosity, and proper acidity of the catalyst. PMID:25009974

  1. Influence of alumina binder content on catalytic performance of Ni/HZSM-5 for hydrodeoxygenation of cyclohexanone.

    PubMed

    Kong, Xiangjin; Liu, Junhai

    2014-01-01

    The influence of the amount of alumina binders on the catalytic performance of Ni/HZSM-5 for hydrodeoxygenation of cyclohexanone was investigated in a fixed-bed reactor. N2 sorption, X-ray diffraction, H2-chemisorption and temperature-programmed desorption of ammonia were used to characterize the catalysts. It can be observed that the Ni/HZSM-5 catalyst bound with 30 wt.% alumina binder exhibited the best catalytic performance. The high catalytic performance may be due to relatively good Ni metal dispersion, moderate mesoporosity, and proper acidity of the catalyst. PMID:25009974

  2. Comparison of Two Preparation Methods on Catalytic Activity and Selectivity of Ru-Mo/HZSM5 for Methane Dehydroaromatization

    DOE PAGESBeta

    Petkovic, Lucia M.; Ginosar, Daniel M.

    2014-01-01

    Catalytic performance of Mo/HZSM5 and Ru-Mo/HZSM5 catalysts prepared by vaporization-deposition of molybdenum trioxide and impregnation with ammonium heptamolybdate was analyzed in terms of catalyst activity and selectivity, nitrogen physisorption analyses, temperature-programmed oxidation of carbonaceous residues, and temperature-programmed reduction. Vaporization-deposition rendered the catalyst more selective to ethylene and coke than the catalyst prepared by impregnation. This result was assigned to lower interaction of molybdenum carbide with the zeolite acidic sites.

  3. Solid-state NMR investigation of acid sites in dealuminated HZSM-5 zeolite.

    PubMed

    Deng, F; Du, Y; Ye, C H

    1996-01-01

    The acid sites and the hydration behaviors of dealuminated HZSM-5 zeolites (calcined at 550, 600, 650, and 700 degrees C) were characterized by high-resolution 1H MAS, 1H{27A1} spin-echo double resonance in combination with 27A1 MAS NMR. Apart from the usually observed peaks for dealuminated zeolite HZSM-5, a narrow plus a broad peak simultaneously appears at ca. 6.9 ppm in the 1H spectra and they exhibit different decay behavior in the 1H [27A1] double-resonance experiments. The existence of the former signal indicates that Lewis acid sites may'be formed in the zeolites after calcination. By means of the spin echo double resonance technique, we observed for the first time a previously unexpected narrow signal at 5.2 ppm, which resonates on the downfield side of Bronsted acid signal (4.3 ppm) and cannot be resolved in the 1H MAS spectra. This new signal is probably due to another kind of Bronsted acid site, locating in the small cages bounded by four- and five-membered rings. Three narrow peaks at 50 ppm, 30 ppm, and 0 ppm are superimposed on a very broad signal in the 27A1 MAS NMR spectra of dried HZSM-5. The intensity of the line at 50 ppm is significantly reduced compared with that of the rehydrated sample. 27A1 MAS NMR suggests that most part of the four-coordinated framework A1 turns into a intermediate case between four- and three-coordinated A1 after the dehydration and this process is reversible upon dehydration/rehydration. While some framework A1 atoms are transformed into three-coordinated A1 species and Lewis acid sites are, thus, generated in the dealuminated zeolites. For the signal at 30 ppm, the hydration leads to a dispersion in the chemical shift or the quadrupole interaction, which broadens its linewidth in hydrated samples. PMID:8970117

  4. Thermodynamics and kinetics of adsorption of selected monoalkylbenzenes in H-ZSM-5

    SciTech Connect

    Schumacher, R.; Karge, H.G.

    1999-03-04

    In this study, the authors present the first systematic investigation of the adsorption of n-propylbenzene, isopropylbenzene, and n-butylbenzene in H-ZSM-5. Both the sorption isotherms and the rate of sorption uptake were investigated at temperatures between 315 and 425 K. The adsorption isotherms are of type 1 and are reasonably well described by the Langmuir-Freundlich model. It is shown that the heat of adsorption of the longer sorbate molecules depends significantly on the concentration, thus indicating an increased influence of sorbate-sorbate interaction. The uptake rates are determined by Fickian diffusion. The activation energies for the diffusion process are identical for all systems (32--36 kJ/mol). The diffusivities are also in the same order of magnitude decreasing noticeably for sorbates with longer or more complex substituents. A tentative explanation based on a simple jump-rate model for intracrystalline diffusion is given.

  5. Structural and electronic features of a Broensted acid site in H-ZSM-5

    SciTech Connect

    Cook, S.J.; Chakraborty, A.K.; Bell, A.T.; Theodorou, D.N. Univ. of California, Berkeley )

    1993-06-24

    The authors report the results of local density functional theory calculations on a Broensted acid site of the zeolite H-ZSM-5. They have investigated the structural and electronic properties of the site. Comparison is made between their results and existing experimental data. It is shown that structural relaxation around an acid site must be performed to obtain accurate energetics for substitution of aluminum into the zeolite framework. The effects of cluster termination are studied by comparing results obtained for both isolated clusters and clusters embedded in a Madelung field generated by the zeolite framework. The properties of the electron density distribution in the region around an acidic proton indicate that the acidic moiety may be characterized as a rather soft acid. 47 refs., 5 figs., 4 tabs.

  6. Magic-angle-spinning NMR studies of acid sites in zeolite H-ZSM-5

    SciTech Connect

    Brunner, E.; Ernst, H.; Freude, D.; Froehlich, T.; Hunger, M.; Pfeifer, H. )

    1991-01-01

    {sup 1}H, {sup 13}C, {sup 27}Al, and {sup 29}Si magic-angle-spinning (MAS) NMR was used to elucidate the nature of the catalytic activity of zeolite H-ZSM-5. {sup 1}H MAS NMR of sealed samples after mild hydrothermal dealumination shows that the enhanced activity for n-hexane cracking is not due to an enhanced Bronstead acidity. The concentrations of the various OH groups and aluminous species suggest that the reason for the enhanced catalytic activity is the interaction of the n-hexane molecule with a bridging hydroxyl group and with extra-framework aluminium species, which give rise to the enhanced activity, cannot be easily removed from their positions, and are therefore immobilized by the zeolitic framework.

  7. Selective dehydration of bio-ethanol to ethylene catalyzed by lanthanum-phosphorous-modified HZSM-5: influence of the fusel.

    PubMed

    Hu, Yaochi; Zhan, Nina; Dou, Chang; Huang, He; Han, Yuwang; Yu, Dinghua; Hu, Yi

    2010-11-01

    Bio-ethanol dehydration to ethylene is an attractive alternative to oil-based ethylene. The influence of fusel, main byproducts in the fermentation process of bio-ethanol production, on the bio-ethanol dehydration should not be ignored. We studied the catalytic dehydration of bio-ethanol to ethylene over parent and modified HZSM-5 at 250°C, with weight hourly space velocity (WHSV) equal to 2.0/h. The influences of a series of fusel, such as isopropanol, isobutanol and isopentanol, on the ethanol dehydration over the catalysts were investigated. The 0.5%La-2%PHZSM-5 catalyst exhibited higher ethanol conversion (100%), ethylene selectivity (99%), and especially enhanced stability (more than 70 h) than the parent and other modified HZSM-5. We demonstrated that the introduction of lanthanum and phosphorous to HZSM-5 could weaken the negative influence of fusel on the formation of ethylene. The physicochemical properties of the catalysts were characterized by ammonia temperature-programmed desorption (NH(3)-TPD), nitrogen adsorption and thermogravimetry (TG)/differential thermogravimetry (DTG)/differential thermal analysis (DTA) (TG/DTG/DTA) techniques. The results indicated that the introduction of lanthanum and phosphorous to HZSM-5 could inhibit the formation of coking during the ethanol dehydration to ethylene in the presence of fusel. The development of an efficient catalyst is one of the key technologies for the industrialization of bio-ethylene. PMID:21058319

  8. Decoupling HZSM-5 catalyst activity from deactivation during upgrading of pyrolysis oil vapors.

    PubMed

    Wan, Shaolong; Waters, Christopher; Stevens, Adam; Gumidyala, Abhishek; Jentoft, Rolf; Lobban, Lance; Resasco, Daniel; Mallinson, Richard; Crossley, Steven

    2015-02-01

    The independent evaluation of catalyst activity and stability during the catalytic pyrolysis of biomass is challenging because of the nature of the reaction system and rapid catalyst deactivation that force the use of excess catalyst. In this contribution we use a modified pyroprobe system in which pulses of pyrolysis vapors are converted over a series of HZSM-5 catalysts in a separate fixed-bed reactor controlled independently. Both the reactor-bed temperature and the Si/Al ratio of the zeolite are varied to evaluate catalyst activity and deactivation rates independently both on a constant surface area and constant acid site basis. Results show that there is an optimum catalyst-bed temperature for the production of aromatics, above which the production of light gases increases and that of aromatics decrease. Zeolites with lower Si/Al ratios give comparable initial rates for aromatics production, but far more rapid catalyst deactivation rates than those with higher Si/Al ratios. PMID:25504857

  9. Ethanol dehydration in HZSM-5 studied by density functional theory: evidence for a concerted process.

    PubMed

    Kim, Seonah; Robichaud, David J; Beckham, Gregg T; Paton, Robert S; Nimlos, Mark R

    2015-04-16

    Dehydration over acidic zeolites is an important reaction class for the upgrading of biomass pyrolysis vapors to hydrocarbon fuels or to precursors for myriad chemical products. Here, we examine the dehydration of ethanol at a Brønsted acid site, T12, found in HZSM-5 using density functional theory (DFT). The geometries of both cluster and mixed quantum mechanics/molecular mechanics (QM:MM) models are prepared from the ZSM-5 crystal structure. Comparisons between these models and different DFT methods are conducted to show similar results among the models and methods used. Inclusion of the full catalyst cavity through a QM:MM approach is found to be important, since activation barriers are computed on average as 7 kcal mol(-1) lower than those obtained with a smaller cluster model. Two different pathways, concerted and stepwise, have been considered when examining dehydration and deprotonation steps. The current study shows that a concerted dehydration process is possible with a lower (4-5 kcal mol(-1)) activation barrier while previous literature studies have focused on a stepwise mechanism. Overall, this work demonstrates that fairly high activation energies (∼50 kcal mol(-1)) are required for ethanol dehydration. A concerted mechanism is favored over a stepwise mechanism because charge separation in the transition state is minimized. QM:MM approaches appear to provide superior results to cluster calculations due to a more accurate representation of charges on framework oxygen atoms. PMID:25802969

  10. Hexane cracking over steamed phosphated zeolite H-ZSM-5: promotional effect on catalyst performance and stability.

    PubMed

    van der Bij, Hendrik E; Meirer, Florian; Kalirai, Sam; Wang, Jian; Weckhuysen, Bert M

    2014-12-15

    The nature behind the promotional effect of phosphorus on the catalytic performance and hydrothermal stability of zeolite H-ZSM-5 has been studied using a combination of (27) Al and (31) P MAS NMR spectroscopy, soft X-ray absorption tomography and n-hexane catalytic cracking, complemented with NH3 temperature-programmed desorption and N2 physisorption. Phosphated H-ZSM-5 retains more acid sites and catalytic cracking activity after steam treatment than its non-phosphated counterpart, while the selectivity towards propylene is improved. It was established that the stabilization effect is twofold. First, the local framework silico-aluminophosphate (SAPO) interfaces, which form after phosphatation, are not affected by steam and hold aluminum atoms fixed in the zeolite lattice, preserving the pore structure of zeolite H-ZSM-5. Second, the four-coordinate framework aluminum can be forced into a reversible sixfold coordination by phosphate. These species remain stationary in the framework under hydrothermal conditions as well. Removal of physically coordinated phosphate after steam-treatment leads to an increase in the number of strong acid sites and increased catalytic activity. We propose that the improved selectivity towards propylene during catalytic cracking can be attributed to local SAPO interfaces located at channel intersections, where they act as impediments in the formation of bulky carbenium ions and therefore suppress the bimolecular cracking mechanism. PMID:25370739

  11. Microstructured fiber@HZSM-5 core-shell catalysts with dramatic selectivity and stability improvement for the methanol-to-propylene process.

    PubMed

    Wang, Xiangyu; Wen, Ming; Wang, Chunzheng; Ding, Jia; Sun, Ying; Liu, Ye; Lu, Yong

    2014-06-18

    We report a macroscopic stainless-steel-fiber@HZSM-5 core-shell catalyst by direct growth of 27 wt% HZSM-5 on a 3D microfibrous structure using 20 μm SS fibers, demonstrating dramatic selectivity and stability improvement in the MTP process. The unprecedented performance is due to the promotion of the olefin methylation/cracking cycle in methanol-to-hydrocarbon catalysis. PMID:24798420

  12. Liquid-phase processing of fast pyrolysis bio-oil using platinum/HZSM-5 catalyst

    NASA Astrophysics Data System (ADS)

    Santos, Bjorn Sanchez

    Recent developments in converting biomass to bio-chemicals and liquid fuels provide a promising sight to an emerging biofuels industry. Biomass can be converted to energy via thermochemical and biochemical pathways. Thermal degradation processes include liquefaction, gasification, and pyrolysis. Among these biomass technologies, pyrolysis (i.e. a thermochemical conversion process of any organic material in the absence of oxygen) has gained more attention because of its simplicity in design, construction and operation. This research study focuses on comparative assessment of two types of pyrolysis processes and catalytic upgrading of bio-oil for production of transportation fuel intermediates. Slow and fast pyrolysis processes were compared for their respective product yields and properties. Slow pyrolysis bio-oil displayed fossil fuel-like properties, although low yields limit the process making it uneconomically feasible. Fast pyrolysis, on the other hand, show high yields but produces relatively less quality bio-oil. Catalytic transformation of the high-boiling fraction (HBF) of the crude bio-oil from fast pyrolysis was therefore evaluated by performing liquid-phase reactions at moderate temperatures using Pt/HZSM-5 catalyst. High yields of upgraded bio-oils along with improved heating values and reduced oxygen contents were obtained at a reaction temperature of 200°C and ethanol/HBF ratio of 3:1. Better quality, however, was observed at 240 °C even though reaction temperature has no significant effect on coke deposition. The addition of ethanol in the feed has greatly attenuated coke deposition in the catalyst. Major reactions observed are esterification, catalytic cracking, and reforming. Overall mass and energy balances in the conversion of energy sorghum biomass to produce a liquid fuel intermediate obtained sixteen percent (16 wt.%) of the biomass ending up as liquid fuel intermediate, while containing 26% of its initial energy.

  13. Impact of solvent for individual steps of phenol hydrodeoxygenation with Pd/C and HZSM-5 as catalysts

    SciTech Connect

    He, Jiayue; Zhao, Chen; Lercher, Johannes A.

    2014-01-01

    Impacts of water, methanol, and hexadecane solvents on the individual steps of phenol hydrodeoxygenation are investigated over Pd/C and HZSM-5 catalyst components at 473 Kin presence of H-2. Hydrodeoxygenation of phenol to cyclohexane includes four individual steps of phenol hydrogenation to cyclohexanone on Pd/C, cyclohexanone hydrogenation to cyclohexanol on Pd/C, cyclohexanol dehydration to cyclohexene on HZSM-5, and cyclohexene hydrogenation to cyclohexane on Pd/C. Individual phenol and cyclohexanone hydrogenation rates are much lower in methanol and hexadecane than in water, while rates of cyclohexanol dehydration and cyclohexene hydrogenation are similar in three solvents. The slow rate in methanol is due to the strong solvation of reactants and the adsorption of methanol on Pd, as well as to the reaction between methanol and the cyclohexanone intermediate. The low solubility of phenol and strong interaction of hexadecane with Pd lead to the slow rate in hexadecane. The apparent activation energies for hydrogenation follow the order E-a phenol > E-a cyclonexanone > E-a cyclohexene, and the sequences of individual reaction rates are reverse in three solvents. The dehydration rates (1.1-1.8 x 10(3) mol mol(BAS)(-1) h(-1))and apparent activation energies (115-124 kJ mol(-1)) are comparable in three solvents. In situ liquid-phase IR spectroscopy shows the rates consistent with kinetics derived from chromatographic evidence in the aqueous phase and verifies that hydrogenation of phenol and cyclohexanone follows reaction orders of 1.0 and 0.55 over Pd/C, respectively. Conversion of cyclohexanol with HZSM-5 shows first-order dependence in approaching the dehydration-hydration equilibrium in the aqueous phase.

  14. Photocatalytic oxidation of NOx over TiO2/HZSM-5 catalysts in the presence of water vapor: Effect of hydrophobicity of zeolites.

    PubMed

    Guo, Gaofei; Hu, Yun; Jiang, Shumei; Wei, Chaohai

    2012-07-15

    TiO(2) hybridized with HZSM-5 zeolites photocatalysts were prepared by a simple solid state dispersion method. The physicochemical properties of the catalysts were characterized by X-ray diffraction, UV-vis diffuse reflectance and FT-IR spectroscopy. The photocatalytic oxidation of NO(x) over TiO(2)/HZSM-5 having different Si/Al ratios was carried out under various levels of humidity and different pre-adsorption times in dark. The TiO(2)/HZSM-5 composite catalysts exhibited higher NO conversion and lower NO(2) formation than pure TiO(2). Pre-adsorption with water vapor and the high humidity during the photoreaction were harmful to the reactivity of TiO(2) hybridized with hydrophilic HZSM-5 zeolite. However, the photocatalytic reactivity of TiO(2) hybridized with hydrophobic zeolite varied little with increase in humidity. The results indicated that the high photocatalytic reactivity of TiO(2)/HZSM-5 catalysts is largely depended on the hydrophobicity of the zeolites. PMID:22579762

  15. Production of light olefins by catalytic conversion of lignocellulosic biomass with HZSM-5 zeolite impregnated with 6wt.% lanthanum.

    PubMed

    Huang, Weiwei; Gong, Feiyan; Fan, Minghui; Zhai, Qi; Hong, Chenggui; Li, Quanxin

    2012-10-01

    Catalytic conversion of rice husk, sawdust, sugarcane bagasse, cellulose, hemicellulose and lignin into olefins was performed with HZSM-5 containing 6 wt.% lanthanum. The olefins yields for different feedstocks decreased in the order: cellulose>hemicellulose>sugarcane bagasse>rice husk>sawdust>lignin. Biomass containing higher content of cellulose or hemicellulose produced more olefins than feedstocks with higher content of lignin. Among the biomass types, sugarcane bagasse provided the highest olefin yield of 0.12 kg olefins/(kg dry biomass) and carbon yield of 21.2C-mol%. Temperature, residence time and the catalyst/feed ratio influenced olefin yield and selectivity. While the HZSM-5 zeolite was catalytically active, the incorporation of lanthanum at 2.9, and 6.0 wt.% increased the production of olefins from rice husk by 15.6% and 26.5%, respectively. The conversion of biomass to light olefins potentially provides an alternative and sustainable route for production of the key petrochemicals. PMID:22858493

  16. Adsorption and Diffusion of Fructose in Zeolite HZSM-5: Selection of Models and Methods for Computational Studies

    SciTech Connect

    Cheng, Lei; Curtiss, Larry A.; Assary, Rajeev S.; Greeley, Jeffrey P.; Kerber, Torsten; Sauer, Joachim

    2011-11-10

    The adsorption and protonation of fructose inHZSM-5 have been studied for the assessment of models for accurate reaction energy calculations and the evaluation of molecular diffusivity. The adsorption and protonation were calculated using 2T, 5T, and 46T clusters as well as a periodic model. The results indicate that the reaction thermodynamics cannot be predicted correctly using small cluster models, such as 2T or 5T, because these small cluster models fail to represent the electrostatic effect of a zeolite cage, which provides additional stabilization to the ion pair formed upon the protonation of fructose. Structural parameters optimized using the 46T cluster model agree well with those of the full periodic model; however, the calculated reaction energies are in significant error due to the poor account of dispersion effects by density functional theory. The dispersion effects contribute -30.5 kcal/mol to the binding energy of fructose in the zeolite pore based on periodic model calculations that include dispersion interactions. The protonation of the fructose ternary carbon hydroxyl group was calculated to be exothermic by 5.5 kcal/mol with a reaction barrier of 2.9 kcal/mol using the periodic model with dispersion effects. Our results suggest that the internal diffusion of fructose in HZSM-5 is very likely to be energetically limited and only occurs at high temperature due to the large size of the molecule.

  17. Adsorption and diffusion of fructose in zeolite HZSM-5: selection of models and methods for computational studies.

    SciTech Connect

    Cheng, L.; Curtiss, L. A.; Assary, R. S.; Greeley, J.; Kerber, T.; Sauer, J.

    2011-09-14

    The adsorption and protonation of fructose in HZSM-5 have been studied for the assessment of models for accurate reaction energy calculations and the evaluation of molecular diffusivity. The adsorption and protonation were calculated using 2T, 5T, and 46T clusters as well as a periodic model. The results indicate that the reaction thermodynamics cannot be predicted correctly using small cluster models, such as 2T or 5T, because these small cluster models fail to represent the electrostatic effect of a zeolite cage, which provides additional stabilization to the ion pair formed upon the protonation of fructose. Structural parameters optimized using the 46T cluster model agree well with those of the full periodic model; however, the calculated reaction energies are in significant error due to the poor account of dispersion effects by density functional theory. The dispersion effects contribute -30.5 kcal/mol to the binding energy of fructose in the zeolite pore based on periodic model calculations that include dispersion interactions. The protonation of the fructose ternary carbon hydroxyl group was calculated to be exothermic by 5.5 kcal/mol with a reaction barrier of 2.9 kcal/mol using the periodic model with dispersion effects. Our results suggest that the internal diffusion of fructose in HZSM-5 is very likely to be energetically limited and only occurs at high temperature due to the large size of the molecule.

  18. An experimental and density functional theory study of the interactions of CH4 with H-ZSM-5

    SciTech Connect

    Khaliullin, Rustam Z.; Bell, Alexis T.; Kazansky, Vladimir B.

    2001-08-25

    The interactions of methane with Bronsted acid sites in H-ZSM-5 were investigated both experimentally and theoretically. Diffuse reflectance infrared spectroscopy was used to acquire spectra for methane adsorbed on H-ZSM-5 at room temperature and at 77 K. Upon adsorption, the v1 and v3 vibrational bands of methane shift by -15 and -23 cm-1, respectively, and the vibrational band for OH groups associated with Bronsted acid sites shifts by -93 cm-1. Quantum chemical calculations conducted at the DFT level of theory with a 6-31g**++ basis set show that the observed shifts for methane are attributable to the effects of the electrostatic field created by the atoms of the zeolite. To represent the influence of the zeolite on the adsorbed methane correctly, it is essential to take into account the effects of the Madelung field, as well as the local effects of the acid center. The calculated shift in the vibrational frequency of the bridging OH group lies within the range observed experimentally. However, the quantitative agreement of the calculated and observed shift is not as good as that seen for the bands of CH4.

  19. Predicting adsorption enthalpies on silicalite and HZSM-5: A benchmark study on DFT strategies addressing dispersion interactions.

    PubMed

    Chiu, Cheng-chau; Vayssilov, Georgi N; Genest, Alexander; Borgna, Armando; Rösch, Notker

    2014-04-15

    We evaluated the accuracy of periodic density functional calculations for adsorption enthalpies of water, alkanes, and alcohols in silicalite and HZSM-5 zeolites using a gradient-corrected density functional with empirical dispersion corrections (PBE-D) as well as a nonlocal correlation functional (vdW-DF2). Results of both approaches agree in acceptable fashion with experimental adsorption energies of alcohols in silicalite, but the adsorption energies for n-alkanes in both zeolite models are overestimated, by 21-46 kJ mol(-1). For PBE-D calculations, the adsorption of alkanes is exclusively determined by the empirical dispersion term, while the generalized gradient approximation-DFT part is purely repulsive, preventing the molecule to come too close to the zeolite walls. The vdW-DF2 results are comparable to those of PBE-D calculations, but the latter values are slightly closer to the experiment in most cases. Thus, both computational approaches are unable to reproduce available experimental adsorption energies of alkanes in silicalite and HZSM-5 zeolite with chemical accuracy. PMID:24550154

  20. Alkane Activation Initiated by Hydride Transfer: Co-conversion of Propane and Methanol over H-ZSM-5 Zeolite.

    PubMed

    Yu, Si-Min; Wu, Jian-Feng; Liu, Chong; Liu, Wei; Bai, Shi; Huang, Jun; Wang, Wei

    2015-06-15

    Co-conversion of alkane with another reactant over zeolite catalysts has emerged as a new approach to the long-standing challenge of alkane transformation. With the aid of solid-state NMR spectroscopy and GC-MS analysis, it was found that the co-conversion of propane and methanol can be readily initiated by hydride transfer at temperatures of ≥449 K over the acidic zeolite H-ZSM-5. The formation of (13)C-labeled methane and singly (13)C-labeled n-butanes in selective labeling experiments provided the first evidence for the initial hydride transfer from propane to surface methoxy intermediates. The results not only provide new insight into carbocation chemistry of solid acids, but also shed light on the low-temperature transformation of alkanes for industrial applications. PMID:25959356

  1. Fast microwave-assisted catalytic co-pyrolysis of corn stover and scum for bio-oil production with CaO and HZSM-5 as the catalyst.

    PubMed

    Liu, Shiyu; Xie, Qinglong; Zhang, Bo; Cheng, Yanling; Liu, Yuhuan; Chen, Paul; Ruan, Roger

    2016-03-01

    This study investigated fast microwave-assisted catalytic co-pyrolysis of corn stover and scum for bio-oil production with CaO and HZSM-5 as the catalyst. Effects of reaction temperature, CaO/HZSM-5 ratio, and corn stover/scum ratio on co-pyrolysis product fractional yields and selectivity were investigated. Results showed that co-pyrolysis temperature was selected as 550°C, which provides the maximum bio-oil and aromatic yields. Mixed CaO and HZSM-5 catalyst with the weight ratio of 1:4 increased the aromatic yield to 35.77 wt.% of feedstock, which was 17% higher than that with HZSM-5 alone. Scum as the hydrogen donor, had a significant synergistic effect with corn stover to promote the production of bio-oil and aromatic hydrocarbons when the H/C(eff) value exceeded 1. The maximum yield of aromatic hydrocarbons (29.3 wt.%) were obtained when the optimal corn stover to scum ratio was 1:2. PMID:26773959

  2. Origin of carbon in aromatic and olefin products derived from HZSM-5 catalyzed co-pyrolysis of cellulose and plastics via isotopic labeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Catalytic pyrolysis over HZSM-5 is an effective method for the conversion of biomass to aromatic hydrocarbons, albeit with low yield and short catalyst lifetimes. Addition of co-reactants rich in carbon and hydrogen can enhance yield and possibly increase catalyst lifetimes by reducing coke formati...

  3. Combustion of chlorinated volatile organic compounds (VOCs) using bimetallic chromium-copper supported on modified H-ZSM-5 catalyst.

    PubMed

    Abdullah, Ahmad Zuhairi; Bakar, Mohamad Zailani Abu; Bhatia, Subhash

    2006-02-28

    The paper reports on the performance of chromium or/and copper supported on H-ZSM-5(Si/Al = 240) modified with silicon tetrachloride (Cr1.5/SiCl4-Z, Cu1.5/SiCl4-Z and Cr1.0Cu0.5/SiCl4-Z) as catalysts in the combustion of chlorinated VOCs (Cl-VOCs). A reactor operated at a gas hourly space velocity (GHSV) of 32,000 h(-1), a temperature between 100 and 500 degrees C with 2500 ppm of dichloromethane (DCM), trichloromethane (TCM) and trichloroethylene (TCE) is used for activity studies. The deactivation study is conducted at a GHSV of 3800 h(-1), at 400 degrees C for up to 12 h with a feed concentration of 35,000 ppm. Treatment with silicon tetrachloride improves the chemical resistance of H-ZSM-5 against hydrogen chloride. TCM is more reactive compared to DCM but it produces more by-products due to its high chlorine content. The stabilization of TCE is attributed to resonance effects. Water vapor increases the carbon dioxide yield through its role as hydrolysis agent forming reactive carbocations and acting as hydrogen-supplying agent to suppress chlorine-transfer reactions. The deactivation of Cr1.0Cu0.5/SiCl4-Z is mainly due to the chlorination of its metal species, especially with higher Cl/H feed. Coking is limited, particularly with DCM and TCM. In accordance with the Mars-van Krevelen model, the weakening of overall metal reducibility due to chlorination leads to a loss of catalytic activity. PMID:16310938

  4. Catalytic fast pyrolysis of mushroom waste to upgraded bio-oil products via pre-coked modified HZSM-5 catalyst.

    PubMed

    Wang, Jia; Zhong, Zhaoping; Ding, Kuan; Xue, Zeyu

    2016-07-01

    In this paper, HZSM-5 catalyst was modified by pre-coked to cover the strong external acid sites by methanol to olefins reaction, and the modified catalysts were then applied to conduct the catalyst fast pyrolysis of mushroom waste for upgraded bio-fuel production. Experiment results showed that the strong external acid sites and specific surface area decreased with pre-coked percentage increasing from 0% to 5.4%. Carbon yields of hydrocarbons increased at first and then decreased with a maximum value of 53.47%. While the obtained oxygenates presented an opposite variation tendency, and the minimum values could be reached when pre-coked percentage was 2.7%. Among the achieved hydrocarbons, toluene and p-xylene were found to be the main products, and the selectivity of p-xylene increased at first and then decreased with a maximum value of 34.22% when the pre-coked percentage was 1.3%, and the selectivity of toluene showed the opposite tendency with a minimum value of 25.47%. PMID:27065226

  5. Gasoline-range hydrocarbons produced from three types of synthesis gas using a Mo/HZSM-5 catalyst

    NASA Astrophysics Data System (ADS)

    Street, Jason Tyler

    Biomass-derived hydrocarbons that include gasoline, diesel, and jet fuel will help replace finite fossil fuel hydrocarbons of the same range. This study showed that temperature could be controlled in a scaled-up reactor system using three types of syngas. The CO conversion, selectivity and amount of product created from each type of syngas were examined. Clean syngas composed of 40% H2, 20% CO, 12% CO2, 2% CH4, and 26% N2 was used to test ideal stoichiometric molar values. Clean syngas composed of 19% H2, 20% CO, 12% CO2, 2% CH4, and 47% N2 was used to test an ideal contaminate-free synthesis gas situation to mimic our particular downdraft gasifier. Gasifier wood syngas composed of 19% H2, 20% CO, 12% CO2, 2% CH4, 46% N2, and 1% O2 was used in this study to determine the feasibility of using gasified biomass syngas to produce gasolinerange hydrocarbons. Key words: Mo/HZSM-5, syngas, synthesis gas, wood syngas, catalyst, gasoline hydrocarbons, gasification, zeolite, oligomerization.

  6. Ethanol Conversion to Hydrocarbons on HZSM-5: Effect of Reaction Conditions and Si/Al Ratio on the Product Distributions

    SciTech Connect

    Ramasamy, Karthikeyan K.; Wang, Yong

    2014-11-17

    The Conversion of ethanol to hydrocarbon over HZSM-5 zeolite with different Si/Al ratios was investigated under various reaction conditions. The catalyst with a higher Si/Al ratio (low acid density) deactivated faster and generated more unsaturated compounds at a similar time-on-stream. Temperature affects the catalytic activity with respect to liquid hydrocarbon generation and the hydrocarbon product composition. At lower temperatures (~300°C), the catalyst deactivated faster with respect to the liquid hydrocarbon formation. Higher temperatures (~400°C) reduced the formation of liquid range hydrocarbons and formed more gaseous fractions. Weight hourly space velocity was also found to affect product selectivity with higher weight hourly space velocity leading to a higher extent of ethylene formation. The experimental results were analyzed in terms of the product composition and the coke content with respect to catalyst time-on-stream and compared with the catalyst lifetime with respect to the variables tested on the conversion of ethanol to hydrocarbon.

  7. The role of propanal in the reaction of 2-propen-1-ol in H-ZSM-5

    SciTech Connect

    Biaglow, A.I.; Sepa, J.; Gorte, R.J.

    1995-07-01

    The adsorption of 2-propen-1-ol and propanal has been studied in H-ZSM-5 using simultaneous temperature programmed desorption (TPD) and thermogravimetric analysis (TGA) measurements and {sup 13}C NMR. For both adsorbates, the TPD-TGA results for both molecules form a large number of complex products. However, for low exposures, less than one molecule/Broensted site, the initial products can be observed. For 2-propene-1-ol, the initial reaction product, formed between 400 and 425 K, is propanal, formed through either a secondary cation or an epoxide intermediate. The intact desorption of propanal at low coverages was also observed in this temperature range. {sup 13}C NMR spectra of 2-propen-1-ol confirm the formation of propanal and condensation products of propanal. Finally, a potential energy model based on gas-phase proton affinities of the various conjugate bases along possible reaction coordinates for the reaction of 2-propen-1-ol explain the observed chemistry well. 21 refs., 7 figs., 1 tab.

  8. Quantitative 3D Fluorescence Imaging of Single Catalytic Turnovers Reveals Spatiotemporal Gradients in Reactivity of Zeolite H-ZSM-5 Crystals upon Steaming.

    PubMed

    Ristanović, Zoran; Hofmann, Jan P; De Cremer, Gert; Kubarev, Alexey V; Rohnke, Marcus; Meirer, Florian; Hofkens, Johan; Roeffaers, Maarten B J; Weckhuysen, Bert M

    2015-05-27

    Optimizing the number, distribution, and accessibility of Brønsted acid sites in zeolite-based catalysts is of a paramount importance to further improve their catalytic performance. However, it remains challenging to measure real-time changes in reactivity of single zeolite catalyst particles by ensemble-averaging characterization methods. In this work, a detailed 3D single molecule, single turnover sensitive fluorescence microscopy study is presented to quantify the reactivity of Brønsted acid sites in zeolite H-ZSM-5 crystals upon steaming. This approach, in combination with the oligomerization of furfuryl alcohol as a probe reaction, allowed the stochastic behavior of single catalytic turnovers and temporally resolved turnover frequencies of zeolite domains smaller than the diffraction limited resolution to be investigated with great precision. It was found that the single turnover kinetics of the parent zeolite crystal proceeds with significant spatial differences in turnover frequencies on the nanoscale and noncorrelated temporal fluctuations. Mild steaming of zeolite H-ZSM-5 crystals at 500 °C led to an enhanced surface reactivity, with up to 4 times higher local turnover rates than those of the parent H-ZSM-5 crystals, and revealed remarkable heterogeneities in surface reactivity. In strong contrast, severe steaming at 700 °C significantly dealuminated the zeolite H-ZSM-5 material, leading to a 460 times lower turnover rate. The differences in measured turnover activities are explained by changes in the 3D aluminum distribution due to migration of extraframework Al-species and their subsequent effect on pore accessibility, as corroborated by time-of-flight secondary ion mass spectrometry (TOF-SIMS) sputter depth profiling data. PMID:25867455

  9. Quantitative 3D Fluorescence Imaging of Single Catalytic Turnovers Reveals Spatiotemporal Gradients in Reactivity of Zeolite H-ZSM-5 Crystals upon Steaming

    PubMed Central

    2015-01-01

    Optimizing the number, distribution, and accessibility of Brønsted acid sites in zeolite-based catalysts is of a paramount importance to further improve their catalytic performance. However, it remains challenging to measure real-time changes in reactivity of single zeolite catalyst particles by ensemble-averaging characterization methods. In this work, a detailed 3D single molecule, single turnover sensitive fluorescence microscopy study is presented to quantify the reactivity of Brønsted acid sites in zeolite H-ZSM-5 crystals upon steaming. This approach, in combination with the oligomerization of furfuryl alcohol as a probe reaction, allowed the stochastic behavior of single catalytic turnovers and temporally resolved turnover frequencies of zeolite domains smaller than the diffraction limited resolution to be investigated with great precision. It was found that the single turnover kinetics of the parent zeolite crystal proceeds with significant spatial differences in turnover frequencies on the nanoscale and noncorrelated temporal fluctuations. Mild steaming of zeolite H-ZSM-5 crystals at 500 °C led to an enhanced surface reactivity, with up to 4 times higher local turnover rates than those of the parent H-ZSM-5 crystals, and revealed remarkable heterogeneities in surface reactivity. In strong contrast, severe steaming at 700 °C significantly dealuminated the zeolite H-ZSM-5 material, leading to a 460 times lower turnover rate. The differences in measured turnover activities are explained by changes in the 3D aluminum distribution due to migration of extraframework Al-species and their subsequent effect on pore accessibility, as corroborated by time-of-flight secondary ion mass spectrometry (TOF-SIMS) sputter depth profiling data. PMID:25867455

  10. Adsorption Device Based on a Langatate Crystal Microbalance for High Temperature High Pressure Gas Adsorption in Zeolite H-ZSM-5.

    PubMed

    Ding, Wenjin; Baracchini, Giulia; Klumpp, Michael; Schwieger, Wilhelm; Dittmeyer, Roland

    2016-01-01

    We present a high-temperature and high-pressure gas adsorption measurement device based on a high-frequency oscillating microbalance (5 MHz langatate crystal microbalance, LCM) and its use for gas adsorption measurements in zeolite H-ZSM-5. Prior to the adsorption measurements, zeolite H-ZSM-5 crystals were synthesized on the gold electrode in the center of the LCM, without covering the connection points of the gold electrodes to the oscillator, by the steam-assisted crystallization (SAC) method, so that the zeolite crystals remain attached to the oscillating microbalance while keeping good electroconductivity of the LCM during the adsorption measurements. Compared to a conventional quartz crystal microbalance (QCM) which is limited to temperatures below 80 °C, the LCM can realize the adsorption measurements in principle at temperatures as high as 200-300 °C (i.e., at or close to the reaction temperature of the target application of one-stage DME synthesis from the synthesis gas), owing to the absence of crystalline-phase transitions up to its melting point (1,470 °C). The system was applied to investigate the adsorption of CO2, H2O, methanol and dimethyl ether (DME), each in the gas phase, on zeolite H-ZSM-5 in the temperature and pressure range of 50-150 °C and 0-18 bar, respectively. The results showed that the adsorption isotherms of these gases in H-ZSM-5 can be well fitted by Langmuir-type adsorption isotherms. Furthermore, the determined adsorption parameters, i.e., adsorption capacities, adsorption enthalpies, and adsorption entropies, compare well to literature data. In this work, the results for CO2 are shown as an example. PMID:27585356

  11. Preparation of HZSM-5 membrane packed CuO-ZnO-Al2O3 nanoparticles for catalysing carbon dioxide hydrogenation to dimethyl ether

    NASA Astrophysics Data System (ADS)

    Liu, Rong; Tian, Haifeng; Yang, Aimei; Zha, Fei; Ding, Jian; Chang, Yue

    2015-08-01

    Spherical carbons were prepared successfully from aqueous glucose using hydrothermal method. After covered with aqueous Cu2+, Zn2+ and Al3+ ions during the co-precipitation treatment, carbons were removed via calcination to yield CuO-ZnO-Al2O3 nanoparticles. HZSM-5 membrane, which was synthesized using tetrapropylammonium hydroxide as templating agent, was packed onto CuO-ZnO-Al2O3 nanoparticles hydrothermally to form HZSM-5 packed CuO-ZnO-Al2O3 nanoparticles. It was characterized by the method of X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and nitrogen sorption measurement. HZSM-5 packed CuO-ZnO-Al2O3 nanoparticles were used as catalysts for the CO2 hydrogenation to dimethyl ether. The catalyst activity was investigated in a fixed-bed reactor. Under the reaction conditions of pressure at 3.0 MPa, space velocity (SV) of 1800 mL gcat-1 h-1, volume ratio of CO2/H2 to 1:3 and temperature at 270 °C, the conversion of CO2 could reach to 48.3%, with a dimethyl ether yield and selectivity of 23.4% and 48.5%, respectively.

  12. Multifaceted effects of HZSM-5 (Proton-exchanged Zeolite Socony Mobil-5) on catalytic cracking of pinewood pyrolysis vapor in a two-stage fixed bed reactor.

    PubMed

    Wang, Yimeng; Wang, Jie

    2016-08-01

    The pinewood was pyrolyzed in the first reactor at a heating rate of 10°Cmin(-1) from room temperature to 700°C, and the vapor was allowed to be cracked through the second reactor in a temperature range of 450-750°C without and with HZSM-5. Attempts were made to determine a wide spectrum of gaseous and liquid products, as well as the mass and element partitions to gas, water, bio-oil, coke and char. HZSM-5 showed a preferential deoxygenation effect via the facilitated decarbonylation and decarboxylation with the inhibited dehydration at 550-600°C. This catalyst also displayed a high selectivity for the formations of aromatic hydrocarbons and olefins by the promoted hydrogen transfer to these products at 550-600°C. The bio-oil produced with HZSM-5 at 500-600°C had the yields of 14.5-16.8%, the high heat values of 39.1-42.4MJkg(-1), and the energy recoveries of 33-35% (all dry biomass basis). PMID:27209452

  13. Microwave-assisted catalytic fast pyrolysis of biomass for bio-oil production using chemical vapor deposition modified HZSM-5 catalyst.

    PubMed

    Zhang, Bo; Zhong, Zhaoping; Chen, Paul; Ruan, Roger

    2015-12-01

    Chemical vapor deposition with tetra-ethyl-orthosilicate as the modifier was applied to deposit the external acid sites of HZSM-5, and the modified HZSM-5 samples were used for the microwave-assisted catalytic fast pyrolysis (MACFP) of biomass for bio-oil production. The experimental results showed that the external acid sites of HZSM-5 decreased significantly when SiO2 deposited amount increased from 0% to 5.9%. For product distribution, the coke yield decreased, the oil fraction yield decreased at first and then increased, and the yields of water and gas first increased and then decreased over the range of SiO2 deposited amount studied. For chemical compositions in oil fraction, the relative contents of aliphatic hydrocarbons, aromatic hydrocarbons and oxygen-containing aromatic compounds first increased to maximum values and then decreased, while the relative content of oxygen-containing aliphatic compounds first decreased and then increased with increasing SiO2 deposited amount. PMID:26318925

  14. Conversion of polyethylene into gasoline-range fuels by two-stage catalytic degradation using silica-alumina and HZSM-5 zeolite

    SciTech Connect

    Uemichi, Yoshio; Nakamura, Junko; Itoh, Toshihiro; Sugioka, Masatoshi; Garforth, A.A.; Dwyer, J.

    1999-02-01

    A two-stage catalytic degradation of polyethylene using amorphous silica-alumina and HZSM-5 zeolite catalysts in series has been developed for converting the polymer into high-quality gasoline-range fuels. Compared with the one-stage degradation over each catalyst, the two-stage method provides some advantages. They are an improved gasoline yield and a high octane number despite low aromatics content. Significant results were obtained when silica-alumina and HZSM-5 were used in a weight ratio of 9:1 as upper and lower catalysts, respectively, in a flow reactor. The reverse sequence of catalysts showed no advantage. It was suggested that large pores and moderate acidity of the silica-alumina loaded in the upper layer operated favorably to catalyze the degradation of polyethylene into liquid hydrocarbons. The resulting oils showed low quality, and they were transformed into high-quality gasoline on the strongly acidic sites of the HZSM-5 loaded in the lower layer at the expense of oil yield. Increases in concentration of isoparaffins and aromatics contributed to the upgrading.

  15. Large zeolite H-ZSM-5 crystals as models for the methanol-to-hydrocarbons process: bridging the gap between single-particle examination and bulk catalyst analysis.

    PubMed

    Hofmann, Jan P; Mores, Davide; Aramburo, Luis R; Teketel, Shewangizaw; Rohnke, Marcus; Janek, Jürgen; Olsbye, Unni; Weckhuysen, Bert M

    2013-06-24

    The catalytic, deactivation, and regeneration characteristics of large coffin-shaped H-ZSM-5 crystals were investigated during the methanol-to-hydrocarbons (MTH) reaction at 350 and 500 °C. Online gas-phase effluent analysis and examination of retained material thereof were used to explore the bulk properties of large coffin-shaped zeolite H-ZSM-5 crystals in a fixed-bed reactor to introduce them as model catalysts for the MTH reaction. These findings were related to observations made at the individual particle level by using polarization-dependent UV-visible microspectroscopy and mass spectrometric techniques after reaction in an in situ microspectroscopy reaction cell. Excellent agreement between the spectroscopic measurements and the analysis of hydrocarbon deposits by means of retained hydrocarbon analysis and time-of-flight secondary-ion mass spectrometry of spent catalyst materials was observed. The obtained data reveal a shift towards more condensed coke deposits on the outer zeolite surface at higher reaction temperatures. Zeolites in the fixed-bed reactor setup underwent more coke deposition than those reacted in the in situ microspectroscopy reaction cell. Regeneration studies of the large zeolite crystals were performed by oxidation in O2 /inert gas mixtures at 550 °C. UV-visible microspectroscopic measurements using the oligomerization of styrene derivatives as probe reaction indicated that the fraction of strong acid sites decreased during regeneration. This change was accompanied by a slight decrease in the initial conversion obtained after regeneration. H-ZSM-5 deactivated more rapidly at higher reaction temperature. PMID:23649944

  16. Quantum chemical modeling of benzene ethylation over H-ZSM-5 approaching chemical accuracy: a hybrid MP2:DFT study.

    PubMed

    Hansen, Niels; Kerber, Torsten; Sauer, Joachim; Bell, Alexis T; Keil, Frerich J

    2010-08-25

    The alkylation of benzene by ethene over H-ZSM-5 is analyzed by means of a hybrid MP2:DFT scheme. Density functional calculations applying periodic boundary conditions (PBE functional) are combined with MP2 energy calculations on a series of cluster models of increasing size which allows extrapolation to the periodic MP2 limit. Basis set truncation errors are estimated by extrapolation of the MP2 energy to the complete basis set limit. Contributions from higher-order correlation effects are accounted for by CCSD(T) coupled cluster calculations. The sum of all contributions provides the "final estimates" for adsorption energies and energy barriers. Dispersion contributes significantly to the potential energy surface. As a result, the MP2:DFT potential energy profile is shifted downward compared to the PBE profile. More importantly, this shift is not the same for reactants and transition structures due to different self-interaction correction errors. The final enthalpies for ethene, benzene, and ethylbenzene adsorption on the Brønsted acid site at 298 K are -46, -78, and -110 kJ/mol, respectively. The intrinsic enthalpy barriers at 653 K are 117 and 119/94 kJ/mol for the one- and two-step alkylation, respectively. Intrinsic rate coefficients calculated by means of transition state theory are converted to apparent Arrhenius parameters by means of the multicomponent adsorption equilibrium. The simulated apparent activation energy (66 kJ/mol) agrees with experimental data (58-76 kJ/mol) within the uncertainty limit of the calculations. Adsorption energies obtained by adding a damped dispersion term to the PBE energies (PBE+D), agree within +/-7 kJ/mol, with the "final estimates", except for physisorption (pi-complex formation) and chemisorption of ethene (ethoxide formation) for which the PBE+D energies are 12.4 and 26.0 kJ/mol, respectively larger than the "final estimates". For intrinsic energy barriers, the PBE+D approach does not improve pure PBE results. PMID:20677757

  17. Insight into the formation of the tert-butyl cation confined inside H-ZSM-5 zeolite from NMR spectroscopy and DFT calculations.

    PubMed

    Huang, Mengdi; Wang, Qiang; Yi, Xianfeng; Chu, Yueying; Dai, Weili; Li, Landong; Zheng, Anmin; Deng, Feng

    2016-08-23

    Solid-state NMR experiments and DFT calculations have been carried out to determine the complex structures of coadsorbed (13)C-labeled tert-butanol and NH3 in acidic H-ZSM-5 zeolite. It is found, besides the physically adsorbed tert-butanol/NH4(+) complex on Brønsted acid sites, the tert-butylamine cation is formed as well, confirming the presence of the tert-butyl cation confined in zeolite channels. Furthermore, (13)C-(27)Al double-resonance solid-state NMR spectroscopy is adopted to determine the host/guest interaction between the carbocation and the zeolite framework. PMID:27400892

  18. Two-step fast microwave-assisted pyrolysis of biomass for bio-oil production using microwave absorbent and HZSM-5 catalyst.

    PubMed

    Zhang, Bo; Zhong, Zhaoping; Xie, Qinglong; Liu, Shiyu; Ruan, Roger

    2016-07-01

    A novel technology of two-step fast microwave-assisted pyrolysis (fMAP) of corn stover for bio-oil production was investigated in the presence of microwave absorbent (SiC) and HZSM-5 catalyst. Effects of fMAP temperature and catalyst-to-biomass ratio on bio-oil yield and chemical components were examined. The results showed that this technology, employing microwave, microwave absorbent and HZSM-5 catalyst, was effective and promising for biomass fast pyrolysis. The fMAP temperature of 500°C was considered the optimum condition for maximum yield and best quality of bio-oil. Besides, the bio-oil yield decreased linearly and the chemical components in bio-oil were improved sequentially with the increase of catalyst-to-biomass ratio from 1:100 to 1:20. The elemental compositions of bio-char were also determined. Additionally, compared to one-step fMAP process, two-step fMAP could promote the bio-oil quality with a smaller catalyst-to-biomass ratio. PMID:27372139

  19. Theoretical study of the aluminum distribution effects on the double proton transfer mechanisms upon adsorption of 4,4'-bipyridine on H-ZSM-5.

    PubMed

    Akacem, Yamina; Castellà-Ventura, Martine; Kassab, Emile

    2012-02-01

    The aluminum distribution effects on the adsorption of 4,4'-bipyridine (44BPY) in the straight channel of H-ZSM-5 simulated by two ten-membered ring clusters (2-10T) have been investigated by DFT methods. The energetic and structural properties of the complexes formed upon interaction of 44BPY with the zeolite Brønsted acid sites for six different aluminum distributions were determined by B3LYP/6-31+G* calculations. Dispersion energies were estimated by performing single point calculations at the MP2 and M06-2X levels. Interaction energies were corrected for basis set superposition error (BSSE). The minimum energy pathways of the double proton transfer from H-ZSM-5 to 44BPY were characterized. Two mechanisms are proposed: a concerted mechanism in which both protons are simultaneously transferred giving the bidentate ion pair complex (44BPYH₂²⁺/2-10T²⁻) and a consecutive mechanism in which one proton is transferred directly leading to the monodentate ion pair complex (44BPYH⁺/2-10T⁻), whereas the second proton can be transferred according to Al distribution. The formation of monodentate or bidentate complexes strongly depends on the Al distribution. PMID:22220497

  20. Propane conversion on Ga-HZSM-5: Effect of aging on the dehydrogenating and acid functions using pyridine as an IR probe

    SciTech Connect

    Meriaudeau, P.; Naccache, C. ); Abdul Hamid, S.B. )

    1993-02-01

    Gallium-loaded zeolite (Ga-HZSM-5) catalysts have been extensively studied in the recent past, not only in respect of their interesting catalytic activity in the aromatization of C[sub 3]-C[sub 5] alkanes (Cyclar Process) but also in respect of theoretical considerations. There is clear evidence that in the reaction of alkanes these catalysts behave as bifunctional catalysts, the acid function being provided by the protons and the dehydrogenation function deriving from Ga[sub 2]O[sub 3] or Ga[sup n+] ions in ionic-exchange positions. Ga-HZSM-5 catalysts deactivate with time on-stream. The deactivation can result from poisoning of the acid centers and/or the dehydrogenating sites by coke deposition or from sintering or phase transformation of the dehydrogenating gallium species. The aim of the present study was to investigate the possible modifications of Ga centers and H[sup +] sites which may result from the propane reaction. The active centers were studied by infrared spectroscopy of adsorbed pyridine, pyridine adsorption being used to probe both H[sup +] and Al, Ga Lewis-acid centers. 11 refs., 2 figs., 1 tab.

  1. Catalytic Upgrading of Biomass-Derived Compounds via C-C Coupling Reactions. Computational and Experimental Studies of Acetaldehyde and Furan Reactions in HZSM-5

    SciTech Connect

    Liu, Cong; Evans, Tabitha J.; Cheng, Lei; Nimlos, Mark R.; Mukarakate, Calvin; Robichaud, David J.; Assary, Rajeev S.; Curtiss, Larry A.

    2015-10-02

    These catalytic C–C coupling and deoxygenation reactions are essential for upgrading of biomass-derived oxygenates to fuel-range hydrocarbons. Detailed understanding of mechanistic and energetic aspects of these reactions is crucial to enabling and improving the catalytic upgrading of small oxygenates to useful chemicals and fuels. Using periodic density functional theory (DFT) calculations, we have investigated the reactions of furan and acetaldehyde in an HZSM-5 zeolite catalyst, a representative system associated with the catalytic upgrading of pyrolysis vapors. Comprehensive energy profiles were computed for self-reactions (i.e., acetaldehyde coupling and furan coupling) and cross-reactions (i.e., acetaldehyde + furan) of this representative mixture. Major products proposed from the computations are further confirmed using temperature controlled mass spectra measurements. Moreover, the computational results show that furan interacts with acetaldehyde in HZSM-5 via an alkylation mechanism, which is more favorable than the self-reactions, indicating that mixing furans with aldehydes could be a promising approach to maximize effective C–C coupling and dehydration while reducing the catalyst deactivation (e.g., coke formation) from aldehyde condensation.

  2. Sandwich-like PdO/CeO2 nanosheet@HZSM-5 membrane hybrid composite for methane combustion: self-redispersion, sintering-resistance and oxygen, water-tolerance.

    PubMed

    Dai, Qiguang; Bai, Shuxing; Lou, Yang; Wang, Xingyi; Guo, Yun; Lu, Guanzhong

    2016-05-14

    PdO/CeO2 nanosheets encapsulated by a monolayer of a continuous and dense HZSM-5 zeolite membrane were prepared by a facile in situ hydrothermal growth process and used as a highly efficient and thermally stable catalyst for methane combustion. Uncoated PdO/CeO2 suffered severe sintering at high temperature or high oxygen concentration. However, the encapsulation of HZSM-5 significantly improved sintering resistance by the suppressing effects of the HZSM-5 coating for the agglomeration of PdOx nanoparticles, resulting in the outstanding thermal stability of PdO/CeO2. Furthermore, the synthesized hybrid materials also exhibited good oxygen- and water-tolerance for methane combustion due to the oxygen or water barrier. In addition, a reactivation behavior was observed due to the self-redispersion of PdOx on CeO2 nanosheets in the reaction atmosphere at high temperature. PMID:27101871

  3. Effects of Coke Deposits on the Catalytic Performance of Large Zeolite H-ZSM-5 Crystals during Alcohol-to-Hydrocarbon Reactions as Investigated by a Combination of Optical Spectroscopy and Microscopy.

    PubMed

    Nordvang, Emily C; Borodina, Elena; Ruiz-Martínez, Javier; Fehrmann, Rasmus; Weckhuysen, Bert M

    2015-11-23

    The catalytic activity of large zeolite H-ZSM-5 crystals in methanol (MTO) and ethanol-to-olefins (ETO) conversions was investigated and, using operando UV/Vis measurements, the catalytic activity and deactivation was correlated with the formation of coke. These findings were related to in situ single crystal UV/Vis and confocal fluorescence micro-spectroscopy, allowing the observation of the spatiotemporal formation of intermediates and coke species during the MTO and ETO conversions. It was observed that rapid deactivation at elevated temperatures was due to the fast formation of aromatics at the periphery of the H-ZSM-5 crystals, which are transformed into more poly-aromatic coke species at the external surface, preventing the diffusion of reactants and products into and out of the H-ZSM-5 crystal. Furthermore, we were able to correlate the operando UV/Vis spectroscopy results observed during catalytic testing with the single crystal in situ results. PMID:26463581

  4. Effects of Coke Deposits on the Catalytic Performance of Large Zeolite H-ZSM-5 Crystals during Alcohol-to-Hydrocarbon Reactions as Investigated by a Combination of Optical Spectroscopy and Microscopy

    PubMed Central

    Nordvang, Emily C; Borodina, Elena; Ruiz-Martínez, Javier; Fehrmann, Rasmus; Weckhuysen, Bert M

    2015-01-01

    The catalytic activity of large zeolite H-ZSM-5 crystals in methanol (MTO) and ethanol-to-olefins (ETO) conversions was investigated and, using operando UV/Vis measurements, the catalytic activity and deactivation was correlated with the formation of coke. These findings were related to in situ single crystal UV/Vis and confocal fluorescence micro-spectroscopy, allowing the observation of the spatiotemporal formation of intermediates and coke species during the MTO and ETO conversions. It was observed that rapid deactivation at elevated temperatures was due to the fast formation of aromatics at the periphery of the H-ZSM-5 crystals, which are transformed into more poly-aromatic coke species at the external surface, preventing the diffusion of reactants and products into and out of the H-ZSM-5 crystal. Furthermore, we were able to correlate the operando UV/Vis spectroscopy results observed during catalytic testing with the single crystal in situ results. PMID:26463581

  5. Sandwich-like PdO/CeO2 nanosheet@HZSM-5 membrane hybrid composite for methane combustion: self-redispersion, sintering-resistance and oxygen, water-tolerance

    NASA Astrophysics Data System (ADS)

    Dai, Qiguang; Bai, Shuxing; Lou, Yang; Wang, Xingyi; Guo, Yun; Lu, Guanzhong

    2016-05-01

    PdO/CeO2 nanosheets encapsulated by a monolayer of a continuous and dense HZSM-5 zeolite membrane were prepared by a facile in situ hydrothermal growth process and used as a highly efficient and thermally stable catalyst for methane combustion. Uncoated PdO/CeO2 suffered severe sintering at high temperature or high oxygen concentration. However, the encapsulation of HZSM-5 significantly improved sintering resistance by the suppressing effects of the HZSM-5 coating for the agglomeration of PdOx nanoparticles, resulting in the outstanding thermal stability of PdO/CeO2. Furthermore, the synthesized hybrid materials also exhibited good oxygen- and water-tolerance for methane combustion due to the oxygen or water barrier. In addition, a reactivation behavior was observed due to the self-redispersion of PdOx on CeO2 nanosheets in the reaction atmosphere at high temperature.PdO/CeO2 nanosheets encapsulated by a monolayer of a continuous and dense HZSM-5 zeolite membrane were prepared by a facile in situ hydrothermal growth process and used as a highly efficient and thermally stable catalyst for methane combustion. Uncoated PdO/CeO2 suffered severe sintering at high temperature or high oxygen concentration. However, the encapsulation of HZSM-5 significantly improved sintering resistance by the suppressing effects of the HZSM-5 coating for the agglomeration of PdOx nanoparticles, resulting in the outstanding thermal stability of PdO/CeO2. Furthermore, the synthesized hybrid materials also exhibited good oxygen- and water-tolerance for methane combustion due to the oxygen or water barrier. In addition, a reactivation behavior was observed due to the self-redispersion of PdOx on CeO2 nanosheets in the reaction atmosphere at high temperature. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01800a

  6. Towards a full understanding of the nature of Ni(II) species and hydroxyl groups over highly siliceous HZSM-5 zeolite supported nickel catalysts prepared by a deposition-precipitation method.

    PubMed

    Chen, Bao-Hui; Chao, Zi-Sheng; He, Hao; Huang, Chen; Liu, Ya-Juan; Yi, Wen-Jun; Wei, Xue-Ling; An, Jun-Fang

    2016-02-14

    Highly siliceous HZSM-5 zeolite supported nickel catalysts prepared by a deposition-precipitation (D-P) method were characterized by Fourier transform infrared (FT-IR), hydrogen temperature programmed reduction (H2-TPR), X-ray diffraction (XRD), N2-absorption/desorption, field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and (27)Al magic-angle nuclear magnetic resonance (MAS NMR) techniques. The results showed that the D-P of nickel species occurred predominantly on the internal surface of highly siliceous HZSM-5 zeolite, in which the internal silanol groups located on the hydroxylated mesopores or nanocavities played a key role. During the D-P process, nickel hydroxide was first deposited-precipitated via olation/polymerization of neutral hydroxoaqua nickel species over the HZSM-5 zeolite. With the progress of the D-P process, 1 : 1 nickel phyllosilicate was formed over the HZSM-5 via the hetero-condensation/polymerization between charged hydroxoaqua nickel species and monomer silicic species generated due to the partial dissolution of the HZSM-5 framework. The 1 : 1 nickel phyllosilicate could also be generated via the hydrolytic adsorption of hydroxoaqua nickel species and their subsequent olation condensation. After calcination, the deposited-precipitated nickel hydroxide was decomposed into nickel oxide, while the 1 : 1 nickel phyllosilicate was transformed into 2 : 1 nickel phyllosilicate. According to the above mechanism, Ni(ii) species were present both in the form of nickel oxide and 2 : 1 nickel phyllosilicate, which were mutually separated from each other, being highly dispersed over HZSM-5 zeolite. PMID:26745008

  7. Methanol conversion to hydrocarbons over zeolite H-ZSM-5: Investigation of the role of CO and ketene in the formation of the initial C-C bond

    SciTech Connect

    Hutchings, G.J.; Johnston, P. ); Hunter, R. ); Van Rensburg, L.J. )

    1993-08-01

    Mechanistic studies concerning the formation of the initial carbon-carbon bond in the methanol conversion reaction over zeolite H-ZSM-5 are described and discussed. In particular, the possible roles of CO as a reaction intermediate or as a catalyst, via the formation of ketene, are evaluated. Experiments using [sup 13]CH[sub 3]OH/[sup 12]CO reactant mixtures demonstrate that no CO is incorporated into ethene, the primary product of this reaction. In addition, CO is found to have no significant effect on the induction period for this reaction. Model experiments for the methylation of ketene by reaction with Me[sub 2]SO[sub 4] and Me[sub 3]O[sup +]SbCl[sub 6][sup [minus

  8. Preparation, characterization and application of nanosized CuO/HZSM-5 as an efficient and heterogeneous catalyst for the N-formylation of amines at room temperature.

    PubMed

    Tajbakhsh, Mahmood; Alinezhad, Heshmatollah; Nasrollahzadeh, Mahmoud; Kamali, Taghi A

    2016-06-01

    An efficient and new method for the synthesis of formamides using HZSM-5 zeolite supported copper oxide nanoparticles as an efficient and heterogeneous catalyst is reported. The catalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS), Brunauer-Emmett-Teller (BET), energy dispersive X-ray spectroscopy (EDS), temperature programmed desorption of ammonia (TPD-NH3) and Fourier transformed infrared spectroscopy (FT-IR). This method has the advantages of eliminating homogeneous catalysts and provides simple methodology with easy work up. Excellent yields of the corresponding formamides were obtained through this cost-effective protocol under solvent-free conditions with shorter reaction time. The catalyst was easily isolated from the reaction mixture by filtration and reused several times without significant loss in its catalytic. PMID:26971067

  9. The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites

    SciTech Connect

    Caro, J.; Buelow, M. ); Kaerger, J.; Pfeifer, H. )

    1988-11-01

    Heterogeneous catalysis is one of the most important applications of zeolites. Therefore, various methods have been developed to determine the strength and concentration of Bronsted acid sites in zeolites. Among them, in the last few years, {sup 1}H MAS NMR has become a powerful tool. In addition to the accessibility of the acid sites probed by chemisorption of N-bases, the steric environment of these catalytically active sites is of importance since it imposes constraints on the geometry of the transition state. However, only a few studies have been reported on this topic. Information was obtained from quantum chemical calculations, catalytic experiments, I.R. spectroscopy, and the arrangement of guest molecules. From these investigations it has been concluded that in H-ZSM-5 the channel intersections should be preferential location centers for the Bronsted acid sites. In adsorption technology, in the use of zeolites as shape-selective adsorbents, modification of the molecular sieve properties by chemisorption of nitrogen-containing bases (N-compounds) has become a common technique. The authors have applied the NMR pulsed field gradient technique to study the influence of chemisorbed N-compounds on transport properties of molecular sieves, considering the chemisorbed compounds as transport obstacles.

  10. Ultrasound assisted co-precipitation of nanostructured CuO-ZnO-Al2O3 over HZSM-5: effect of precursor and irradiation power on nanocatalyst properties and catalytic performance for direct syngas to DME.

    PubMed

    Allahyari, Somaiyeh; Haghighi, Mohammad; Ebadi, Amanollah; Hosseinzadeh, Shahin

    2014-03-01

    Nanostructured CuO-ZnO-Al2O3/HZSM-5 was synthesized from nitrate and acetate precursors using ultrasound assisted co-precipitation method under different irradiation powers. The CuO-ZnO-Al2O3/HZSM-5 nanocatalysts were characterized using XRD, FESEM, BET, FTIR and EDX Dot-mapping analyses. The results indicated precursor type and irradiation power have significant influences on phase structure, morphology, surface area and functional groups. It was observed that the acetate formulated CuO-ZnO-Al2O3/HZSM-5 nanocatalyst have smaller CuO crystals with better dispersion and stronger interaction between components in comparison to nitrate based nanocatalysts. Ultrasound assisted co-precipitation synthesis method resulted in nanocatalyst with more uniform morphology compared to conventional method and increasing irradiation power yields smaller particles with better dispersion and higher surface area. Additionally the crystallinity of CuO is lower at high irradiation powers leading to stronger interaction between metal oxides. The nanocatalysts performance were tested at 200-300 °C, 10-40 bar and space velocity of 18,000-36,000 cm(3)/g h with the inlet gas composition of H2/CO = 2/1 in a stainless steel autoclave reactor. The acetate based nanocatalysts irradiated with higher levels of power exhibited better reactivity in terms of CO conversion and DME yield. While there is an optimal temperature for CO conversion and DME yield in direct synthesis of DME, CO conversion and DME yield both increase with the pressure increase. Furthermore ultrasound assisted co-precipitation method yields more stable CuO-ZnO-Al2O3/HZSM-5 nanocatalyst while conventional precipitated nanocatalyst lost their activity ca. 18% and 58% in terms of CO conversion and DME yield respectively in 24 h time on stream test. PMID:24409466

  11. A {sup 13}C NMR study of the condensation chemistry of acetone and acetaldehyde adsorbed at the Bronsted acid sites in H-ZSM-5

    SciTech Connect

    Biaglow, A.I.; Sepa, J.; Gorte, R.J.

    1995-02-01

    Several bimolecular, acid-catalyzed condensation reactions of acetone and acetaldehyde have been examined in H-ZSM-5, along with the adsorption complexes formed by the products, using {sup 13}C NMR. For acetone, the hydrogen-bonded adsorption complex is stable at room temperature and coverages below one molecule per Broensted acid site. Reaction to mesityl oxide occurs only at higher coverages or temperatures, which are necessary to induce site exchange. The adsorption complex exhibits reaction chemistry analogous to that observed in solution phase, forming adsorption complexes of chloroacetone upon exposure to Cl{sub 2} and of imines upon exposure to NH{sub 3} or dimethylamine. The reactions of acetaldehyde to crotonaldehyde and imines are similar, although they occur at a faster rate due to the higher mobility of this molecule. The adsorption complexes formed by acetone, acetaldehyde, and their condensation products can all be described as rigid, hydrogen-bonded complexes at low coverages. Complexes formed from imines and enamines exhibit isotropic chemical shifts nearly identical to those observed in magic acids, indicating that proton transfer is nearly complete for these molecules. The extent of proton transfer for the remaining molecules varies with the proton affinity of the molecule, ranging from close to complete proton transfer for mesityl oxide and crotonaldehyde to almost complete absence of proton transfer for the chloroacetones. The differences and similarities between these reactions in the zeolite and in solution phase are discussed, along with the implications for understanding the primary processes responsible for these reactions in zeolites. 34 refs., 16 figs., 1 tab.

  12. Direct Detection of Supramolecular Reaction Centers in the Methanol-to-Olefins Conversion over Zeolite H-ZSM-5 by (13)C-(27)Al Solid-State NMR Spectroscopy.

    PubMed

    Wang, Chao; Wang, Qiang; Xu, Jun; Qi, Guodong; Gao, Pan; Wang, Weiyu; Zou, Yunyun; Feng, Ningdong; Liu, Xiaolong; Deng, Feng

    2016-02-12

    Hydrocarbon-pool chemistry is important in methanol to olefins (MTO) conversion on acidic zeolite catalysts. The hydrocarbon-pool (HP) species, such as methylbenzenes and cyclic carbocations, confined in zeolite channels during the reaction are essential in determining the reaction pathway. Herein, we experimentally demonstrate the formation of supramolecular reaction centers composed of organic hydrocarbon species and the inorganic zeolite framework in H-ZSM-5 zeolite by advanced (13)C-(27)Al double-resonance solid-state NMR spectroscopy. Methylbenzenes and cyclic carbocations located near Brønsted acid/base sites form the supramolecular reaction centers in the zeolite channel. The internuclear spatial interaction/proximity between the (13)C nuclei (associated with HP species) and the (27) Al nuclei (associated with Brønsted acid/base sites) determines the reactivity of the HP species. The closer the HP species are to the zeolite framework Al, the higher their reactivity in the MTO reaction. PMID:26732748

  13. Formation of carboxylic acids from alcohols and olefins in zeolite H-ZSM-5 under mild conditions via trapping of alkyl carbenium ions with carbon monoxide: An in situ {sup 13}C solid state NMR study

    SciTech Connect

    Stepanov, A.G.; Luzgin, M.V.; Romannikov, V.N.; Sidelnikov, V.N.; Zamaraev K.I.

    1996-12-01

    Using in situ {sup 13}C solid state MAS NMR (for some reagents in combination with ex situ GC-MS), it is shown that butyl alcohols and olefins (ethene, isobutene, octene-1) undergo carbonylation to form carboxylic acids (the Koch reaction) with high conversion on zeolite H-ZSM-5 at 296-373 K. The reactions proceed without application of pressurized conditions, just upon coadsorption of CO and alcohols or CO, H{sub 2}O, and olefins on zeolite. The observed Koch reaction under mild conditions provides strong evidence for the formation of alkyl carbenium ions from alcohols and olefins on the zeolites as crucial reaction intermediates. Of the family of carbenium ions, CO reacts selectively with tertiary cations to produce tertiary carboxylic acids, unless the carbonylated molecule is too large for more bulky tertiary moieties to be accommodated and carbonylated in the narrow pores of H-ZSM05. Thus, t-BuOH, i-BuOH, and isobutene produce trimethylacetic acid with high selectivity and conversion, while ethene transforms selectively into 2-methyl-2-ethyl butyric acid. Reaction of octene-1 molecules with CO and H{sub 2}O results in acids of the C{sub 8}H{sub 17}COOH and C{sub 16}H{sub 33}COOH families with predominantly linear hydrocarbon chains. The data obtained may open up new possibilities in using solid acids in organic synthesis as carbonylation catalysts under mild conditions i.e., low temperature and normal atmospheric pressure. 55 refs., 8 figs.

  14. Pentane conversion on dealuminated H-Y and HZSM-5

    SciTech Connect

    Hong, Y.; Gruver, V.; Fripiat, J.J.

    1996-07-01

    Kinetics of n-pentane conversion was studied in relation to the acidity of Y zeolites. Selectivity to isomerization vs. cracking depends mainly on the zeolite structure and the partial clogging of the pores. 34 refs., 5 figs., 7 tabs.

  15. Carbocation Stability in H-ZSM5 at High Temperature

    SciTech Connect

    Ferguson, Glen A.; Cheng, Lei; Bu, Lintao; Kim, Seonah; Robichaud, David J.; Nimlos, Mark R.; Curtiss, Larry A.; Beckham, Gregg T.

    2015-10-26

    Zeolites are common catalysts for multiple industrial applications, including alcohol dehydration to produce olefins, and given their commercial importance, reaction mechanisms in zeolites have long been proposed and studied. Some proposed reaction mechanisms for alcohol dehydration exhibit noncyclic carbocation intermediates or transition states that resemble carbocations, and several previous studies suggest that the tert-butyl cation is the only noncyclic cation more stable than the corresponding chemisorbed species with the hydrocarbon bound to the framework oxygen (i.e., an alkoxide). To determine if carbocations can exist at high temperatures in zeolites, where these catalysts are finding new applications for biomass vapor-phase upgrading (~500 °C), the stability of carbocations and the corresponding alkoxides were calculated with two ONIOM embedding methods (M06-2X/6-311G(d,p):M06-2X/3-21G) and (PBE-D3/6-311G(d,p):PBE-D3/3-21G) and plane-wave density functional theory (DFT) using the PBE functional corrected with entropic and Tkatchenko–Scheffler van der Waals corrections. Additionally, the embedding methods tested are unreliable at finding minima for primary carbocations, and only secondary or higher carbocations can be described with embedding methods consistent with the periodic DFT results. The relative energy between the carbocations and alkoxides differs significantly between the embedding and the periodic DFT methods. The difference is between ~0.23 and 14.30 kcal/mol depending on the molecule, the model, and the functional chosen for the embedding method. At high temperatures, the pw-DFT calculations predict that the allyl, isopropyl, and sec-butyl cations exhibit negligible populations while acetyl and tert-butyl cations exhibit significant populations (>10%). Furthermore, the periodic DFT results indicate that mechanisms including secondary and tertiary carbocations intermediates or carbocations stabilized by adjacent oxygen or double bonds are possible at high temperatures relevant to some industrial uses of zeolite catalysts, although as the minority species in most cases.

  16. Carbocation Stability in H-ZSM5 at High Temperature.

    PubMed

    Ferguson, Glen A; Cheng, Lei; Bu, Lintao; Kim, Seonah; Robichaud, David J; Nimlos, Mark R; Curtiss, Larry A; Beckham, Gregg T

    2015-11-19

    Zeolites are common catalysts for multiple industrial applications, including alcohol dehydration to produce olefins, and given their commercial importance, reaction mechanisms in zeolites have long been proposed and studied. Some proposed reaction mechanisms for alcohol dehydration exhibit noncyclic carbocation intermediates or transition states that resemble carbocations, and several previous studies suggest that the tert-butyl cation is the only noncyclic cation more stable than the corresponding chemisorbed species with the hydrocarbon bound to the framework oxygen (i.e., an alkoxide). To determine if carbocations can exist at high temperatures in zeolites, where these catalysts are finding new applications for biomass vapor-phase upgrading (∼500 °C), the stability of carbocations and the corresponding alkoxides were calculated with two ONIOM embedding methods (M06-2X/6-311G(d,p):M06-2X/3-21G) and (PBE-D3/6-311G(d,p):PBE-D3/3-21G) and plane-wave density functional theory (DFT) using the PBE functional corrected with entropic and Tkatchenko-Scheffler van der Waals corrections. The embedding methods tested are unreliable at finding minima for primary carbocations, and only secondary or higher carbocations can be described with embedding methods consistent with the periodic DFT results. The relative energy between the carbocations and alkoxides differs significantly between the embedding and the periodic DFT methods. The difference is between ∼0.23 and 14.30 kcal/mol depending on the molecule, the model, and the functional chosen for the embedding method. At high temperatures, the pw-DFT calculations predict that the allyl, isopropyl, and sec-butyl cations exhibit negligible populations while acetyl and tert-butyl cations exhibit significant populations (>10%). Moreover, the periodic DFT results indicate that mechanisms including secondary and tertiary carbocations intermediates or carbocations stabilized by adjacent oxygen or double bonds are possible at high temperatures relevant to some industrial uses of zeolite catalysts, although as the minority species in most cases. PMID:26501585

  17. The Catalytic Cracking of Hydrocarbons: Paraffins in the HZSM-5 Zeolite

    SciTech Connect

    Martinez-Magadan, Jose M.; Mercado, Sergio M.; Santamaria, Ruben

    2001-11-19

    An elementary reaction during cracking of a hydrocarbon in a nanoporous silicalite catalyst includes ejection of a hydrid ion as shown in the picture. The reaction was simulated by means of quantum molecular dynamics. The central goal of petroleum refineries consists in the transformation of crude oil into a variety of useful products, among which fuels play a crucial role.[1] Presently, important companies are using state-of-the-art technology to investigate new and more efficient refining processes, that may additionally lead to a cleaner environment. Unfortunately, this type of investigation demands costly investment and is highly empirical[2, 3] due to the number of variables, properties, and pathways that characterize the refining processes. On the other hand, the intense competition among catalyst manufacturers has challenged basic research.

  18. Dehydration pathways of 1-propanol on HZSM-5 in the presence and absence of water

    SciTech Connect

    Zhi, Yuchun; Shi, Hui; Mu, Linyu; Liu, Yue; Mei, Donghai; Camaioni, Donald M.; Lercher, Johannes A.

    2015-12-23

    The Brønsted acid-catalyzed gas-phase dehydration of 1-propanol (0.075-4 kPa) was studied on zeolite H-MFI (Si/Al = 26, containing minimal amounts of extraframework Al moieties) in the absence and presence of co-fed water (0-2.5 kPa) at 413-443 K. It is shown that propene can be formed from monomeric and dimeric adsorbed 1-propanol. The stronger adsorption of 1-propanol relative to water indicates that the reduced dehydration rates in the presence of water are not a consequence of the competitive adsorption between 1-propanol and water. Instead, the deleterious effect is related to the different extents of stabilization of adsorbed intermediates and the relevant elimination/substitution transition states by water. Water stabilizes the adsorbed 1-propanol monomer significantly more than the elimination transition state, leading to a higher activation barrier and a greater entropy gain for the rate-limiting step, which eventually leads to propene. In a similar manner, an excess of 1-propanol stabilizes the adsorbed state of 1-propanol more than the elimination transition state. In comparison with the monomer-mediated pathway, adsorbed dimer and the relevant transition states for propene and ether formation are similarly, while less effectively, stabilized by intrazeolite water molecules. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, and was performed in part using the Molecular Sciences Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located and the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for DOE.

  19. H-ZSM5 Catalyzed co-pyrolysis of biomass and plastics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study aims at addressing two important problems vital to agriculture, disposal of agricultural plastics and production of drop-in fuels from biomass via co-pyrolysis of both feedstocks. Mixtures of biomass (switchgrass, cellulose, xylan and lignin) and plastic (polyethylene terephthalate (PET),...

  20. Biological mineral range effects on biomass conversion to aromatic hydrocarbons via catalytic fast pyrolysis over HZSM-5

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A set of 20 biomass samples, comprising 10 genotypes of switchgrass, sorghum and miscanthus grown in two different soils with high and low poultry manure input conditions, and having a wide biological range of mineral content, were subjected to catalytic fast pyrolysis (CFP) over HZMS-5 using py-G...

  1. Selective transformation of syngas into gasoline-range hydrocarbons over mesoporous H-ZSM-5-supported cobalt nanoparticles.

    PubMed

    Cheng, Kang; Zhang, Lei; Kang, Jincan; Peng, Xiaobo; Zhang, Qinghong; Wang, Ye

    2015-01-26

    Bifunctional Fischer-Tropsch (FT) catalysts that couple uniform-sized Co nanoparticles for CO hydrogenation and mesoporous zeolites for hydrocracking/isomerization reactions were found to be promising for the direct production of gasoline-range (C5-11 ) hydrocarbons from syngas. The Brønsted acidity results in hydrocracking/isomerization of the heavier hydrocarbons formed on Co nanoparticles, while the mesoporosity contributes to suppressing the formation of lighter (C1-4 ) hydrocarbons. The selectivity for C5-11 hydrocarbons could reach about 70 % with a ratio of isoparaffins to n-paraffins of approximately 2.3 over this catalyst, and the former is markedly higher than the maximum value (ca. 45 %) expected from the Anderson-Schulz-Flory distribution. By using n-hexadecane as a model compound, it was clarified that both the acidity and mesoporosity play key roles in controlling the hydrocracking reactions and thus contribute to the improved product selectivity in FT synthesis. PMID:25424473

  2. Henrique da Rocha Lima.

    PubMed

    Bernardes Filho, Fred; Avelleira, João Carlos Regazzi

    2015-01-01

    Brazilian physician and researcher Henrique da Rocha Lima was born in 1879 in the city of Rio de Janeiro, where he studied medicine and obtained the degree of M.D. in 1901. He specialized in Clinical Medicine in Germany and was the ambassador in European countries of the scientific medicine that emerged from the Oswaldo Cruz Institute in the early twentieth century. Rocha Lima has discovered the causative agent of typhus and had a major contribution to the studies of yellow fever, Chagas disease, Carrión's disease and histoplasmosis. His genius, his research and his discoveries projected his name, and, with it, the image of Brazil in the international scientific scene. PMID:26131867

  3. Henrique da Rocha Lima*

    PubMed Central

    Bernardes Filho, Fred; Avelleira, João Carlos Regazzi

    2015-01-01

    Brazilian physician and researcher Henrique da Rocha Lima was born in 1879 in the city of Rio de Janeiro, where he studied medicine and obtained the degree of M.D. in 1901. He specialized in Clinical Medicine in Germany and was the ambassador in European countries of the scientific medicine that emerged from the Oswaldo Cruz Institute in the early twentieth century. Rocha Lima has discovered the causative agent of typhus and had a major contribution to the studies of yellow fever, Chagas disease, Carrión’s disease and histoplasmosis. His genius, his research and his discoveries projected his name, and, with it, the image of Brazil in the international scientific scene. PMID:26131867

  4. Leonardo da Vinci and the Downburst.

    NASA Astrophysics Data System (ADS)

    Gedzelman, Stanley David

    1990-05-01

    Evidence from the drawings, experiments, and writings of Leonardo da Vinci are presented to demonstrate that da Vinci recognized and, possibly, discovered the downburst and understood its associated airflow. Other early references to vortex flows resembling downbursts are mentioned.

  5. The major histocompatibility complex genes impact pain response in DA and DA.1U rats.

    PubMed

    Guo, Yuan; Yao, Fan-Rong; Cao, Dong-Yuan; Li, Li; Wang, Hui-Sheng; Xie, Wen; Zhao, Yan

    2015-08-01

    Our recent studies have shown that the difference in basal pain sensitivity to mechanical and thermal stimulation between Dark-Agouti (DA) rats and a novel congenic DA.1U rats is major histocompatibility complex (MHC) genes dependent. In the present study, we further used DA and DA.1U rats to investigate the role of MHC genes in formalin-induced pain model by behavioral, electrophysiological and immunohistochemical methods. Behavioral results showed biphasic nociceptive behaviors increased significantly following the intraplantar injection of formalin in the hindpaw of DA and DA.1U rats. The main nociceptive behaviors were lifting and licking, especially in DA rats (P<0.001 and P<0.01). The composite pain scores (CPS) in DA rats were significantly higher than those in DA.1U rats in both phases of the formalin test (P<0.01). Electrophysiological results also showed the biphasic increase in discharge rates of C and Aδ fibers of L5 dorsal root in the two strains, and the net change of the discharge rate of DA rats was significantly higher than that of DA.1U rats (P<0.05). The mechanical thresholds decreased after formalin injection in both strains (P<0.01), and the net change in the mechanical threshold in DA was greater than that in DA.1U rats (P<0.05). The expression of RT1-B, representation of MHC class II molecule, in laminae I-II of L4/5 spinal cord in DA rats was significantly higher than that in DA.1U rats in the respective experimental group (P<0.05). These results suggested that both DA and DA.1U rats exhibited nociceptive responses in formalin-induced pain model and DA rats were more sensitive to noxious chemical stimulus than DA.1U rats, indicating that MHC genes might contribute to the difference in pain sensitivity. PMID:25861730

  6. Fluorine substitution enhanced photovoltaic performance of a D-A(1)-D-A(2) copolymer.

    PubMed

    Dang, Dongfeng; Chen, Weichao; Yang, Renqiang; Zhu, Weiguo; Mammo, Wendimagegn; Wang, Ergang

    2013-10-18

    A new alternating donor-acceptor (D-A1-D-A2) copolymer containing two electron-deficient moieties, isoindigo and quinoxaline, was synthesized. The photovoltaic performance of this polymer could be improved by incorporating fluorine atoms into the quinoxaline units, resulting in an efficiency of 6.32%. This result highlights the attractive promise of D-A1-D-A2 copolymers for high-performance bulk heterojunction solar cells. PMID:24000353

  7. Autocorrelation descriptor improvements for QSAR: 2DA_Sign and 3DA_Sign.

    PubMed

    Sliwoski, Gregory; Mendenhall, Jeffrey; Meiler, Jens

    2016-03-01

    Quantitative structure-activity relationship (QSAR) is a branch of computer aided drug discovery that relates chemical structures to biological activity. Two well established and related QSAR descriptors are two- and three-dimensional autocorrelation (2DA and 3DA). These descriptors encode the relative position of atoms or atom properties by calculating the separation between atom pairs in terms of number of bonds (2DA) or Euclidean distance (3DA). The sums of all values computed for a given small molecule are collected in a histogram. Atom properties can be added with a coefficient that is the product of atom properties for each pair. This procedure can lead to information loss when signed atom properties are considered such as partial charge. For example, the product of two positive charges is indistinguishable from the product of two equivalent negative charges. In this paper, we present variations of 2DA and 3DA called 2DA_Sign and 3DA_Sign that avoid information loss by splitting unique sign pairs into individual histograms. We evaluate these variations with models trained on nine datasets spanning a range of drug target classes. Both 2DA_Sign and 3DA_Sign significantly increase model performance across all datasets when compared with traditional 2DA and 3DA. Lastly, we find that limiting 3DA_Sign to maximum atom pair distances of 6 Å instead of 12 Å further increases model performance, suggesting that conformational flexibility may hinder performance with longer 3DA descriptors. Consistent with this finding, limiting the number of bonds in 2DA_Sign from 11 to 5 fails to improve performance. PMID:26721261

  8. Virtual observatory publishing with DaCHS

    NASA Astrophysics Data System (ADS)

    Demleitner, M.; Neves, M. C.; Rothmaier, F.; Wambsganss, J.

    2014-11-01

    The Data Center Helper Suite DaCHS is an integrated publication package for building VO and Web services, supporting the entire workflow from ingestion to data mapping to service definition. It implements all major data discovery, data access, and registry protocols defined by the VO. DaCHS in this sense works as glue between data produced by the data providers and the standard protocols and formats defined by the VO. This paper discusses central elements of the design of the package and gives two case studies of how VO protocols are implemented using DaCHS' concepts.

  9. Origin of the DA and non-DA white dwarf stars

    NASA Technical Reports Server (NTRS)

    Shipman, Harry L.

    1989-01-01

    Various proposals for the bifurcation of the white dwarf cooling sequence are reviewed. 'Primordial' theories, in which the basic bifurcation of the white dwarf sequence is rooted in events predating the white dwarf stage of stellar evolution, are discussed, along with the competing 'mixing' theories in which processes occurring during the white dwarf stage are responsible for the existence of DA or non-DA stars. A new proposal is suggested, representing a two-channel scenario. In the DA channel, some process reduces the hydrogen layer mass to the value of less than 10 to the -7th. The non-DA channel is similar to that in the primordial scenario. These considerations suggest that some mechanism operates in both channels to reduce the thickness of the outermost layer of the white dwarf. It is also noted that accretion from the interstellar medium has little to do with whether a particular white dwarf becomes a DA or a non-DA star.

  10. Measurement of D->A Momentum Aperture and Test of D->A Field Qualities

    SciTech Connect

    Halling, Mike

    1992-02-27

    The data presented here were taken during two shifts dedicated to D->A studies. The goal during both of these study periods was a test of the field quality of the D->A channel devices, but for the first study period on 10/21/91 the TBT system was not operational so we simply measured the transfer efficiency as a function of momentum. The conclusion from these measurements is as follows: (1) The momentum aperture of the D->A channel is smaller than expected. (2) The restriction is in physical space is somewhere near A:IKIK. (3) The field quality of the injection channel devices is adequate.

  11. The local effect of octreotide on mechanical pain sensitivity is more sensitive in DA rats than DA.1U rats.

    PubMed

    Yao, Fan-Rong; Wang, Hui-Sheng; Guo, Yuan; Zhao, Yan

    2016-02-01

    A recent study by the authors indicated that major histocompatibility complex (MHC) genes are associated with the differences in basal pain sensitivity and in formalin model between Dark-Agouti (DA) and novel congenic DA.1U rats, which have the same genetic background as DA rats except for the u alleles of MHC. The objective of the present study is to investigate whether there is a difference in the pristane-induced arthritis (PIA) model and local analgesic effect of octreotide (OCT) between DA and DA.1U rats. The hindpaw mechanical withdrawal threshold (MWT) and heat withdrawal latency (HWL) were observed. The C unit firings of the tibial nerve evoked by non-noxious and noxious toe movements were recorded by electrophysiological methods in normal and PIA models in DA and DA.1U rats before and after local OCT administration. The expression of somatostatin receptor 2A (SSTR2A) was observed by immunohistochemistry. The results demonstrate that DA rats have a higher mechanical sensitivity than DA.1U rats after PIA. Local OCT administration significantly elevated MWT in DA rats under normal and PIA sate, but not in DA.1U rats. The electrophysiological experiments showed OCT significantly attenuated the firings of C units evoked by non-noxious and noxious stimulation in DA rats more than those in DA.1U rats both in normal and PIA states. In addition, the expression of SSTR2A in the dorsal horn of the spinal cord was significantly higher in DA than in DA.1U rats. All of the findings suggest a higher local analgesic effect of OCT in DA rats than DA.1U rats, which might be associated with the MHC genes. PMID:26606866

  12. Hidden sketches by Leonardo da Vinci revealed

    NASA Astrophysics Data System (ADS)

    Dumé, Belle

    2009-02-01

    Three drawings on the back of Leonardo da Vinci's The Virgin and Child with St Anne (circa 1508) have been discovered by researchers led by Michel Menu from the Centre de Recherche et de Restauration des Musées de France (C2RMF) and the Louvre Museum in Paris.

  13. Common colds on Tristan da Cunha

    PubMed Central

    Shibli, M.; Gooch, S.; Lewis, H. E.; Tyrrell, D. A. J.

    1971-01-01

    Eight epidemics of respiratory disease have been observed among islanders of Tristan da Cunha. They seem to be initiated by the arrival of ships and transmission seemed to occur as a result of close human contact but could not always be traced. Islanders suffered from less colds than those in less isolated communities. PMID:5282927

  14. The PAN-DA data acquisition system

    SciTech Connect

    Petravick, D.; Berg, D.; Berman, E.; Bernett, M.; Constanta-Fanourakis, P.; Dorries, T.; Haire, M.; Kaczar, K; MacKinnon, B.; Moore, C.; Nicinski, T.; Oleynik, G.; Pordes, R.; Sergey, G.; Votava, M.; White, V.

    1989-05-01

    The Online and Data Acquisition software groups at Fermi National Accelerator Laboratory have extended the VAXONLINE data acquisition package to include a VME based data path. The resulting environment, PAN-DA, provides a high throughput for logging, filtering, formatting and selecting events. 10 refs., 1 fig.

  15. How to Think Like Leonardo da Vinci

    ERIC Educational Resources Information Center

    Caouette, Ralph

    2008-01-01

    To be effective and relevant in twenty-first-century learning, art needs to be more inclusive. In this article, the author discusses how teachers can find a good example in Leonardo da Vinci for building an art program. His art, design, and curiosity are the perfect foundation for any art program, at any level. (Contains 3 resources and 3 online…

  16. 40 CFR 60.51Da - Reporting requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Generating Units § 60.51Da Reporting requirements. (a) For SO2, NOX, PM, and NOX plus CO emissions, the... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Reporting requirements. 60.51Da Section 60.51Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

  17. 40 CFR 60.47Da - Commercial demonstration permit.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Commercial demonstration permit. 60.47Da Section 60.47Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Steam Generating Units § 60.47Da Commercial demonstration permit. (a) An owner or operator of...

  18. 40 CFR 60.51Da - Reporting requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Generating Units § 60.51Da Reporting requirements. (a) For SO2, NOX, PM, and NOX plus CO emissions, the... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Reporting requirements. 60.51Da Section 60.51Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

  19. 40 CFR 60.47Da - Commercial demonstration permit.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Commercial demonstration permit. 60.47Da Section 60.47Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Steam Generating Units § 60.47Da Commercial demonstration permit. (a) An owner or operator of...

  20. 40 CFR 60.51Da - Reporting requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Generating Units § 60.51Da Reporting requirements. (a) For SO2, NOX, PM, and NOX plus CO emissions, the... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Reporting requirements. 60.51Da Section 60.51Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

  1. 40 CFR 60.47Da - Commercial demonstration permit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Commercial demonstration permit. 60.47Da Section 60.47Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Steam Generating Units § 60.47Da Commercial demonstration permit. (a) An owner or operator of...

  2. 32 CFR 516.25 - DA Form 4.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 3 2011-07-01 2009-07-01 true DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC RELATIONS LITIGATION Reporting Legal Proceedings to HQDA § 516.25 DA Form 4. (a) General. The DA Form 4 (See figure...

  3. A Day in the Life at DaVita Academy

    ERIC Educational Resources Information Center

    Weinstein, Margery

    2010-01-01

    When a company name means "giving life," the bar for learning and development programs is held high. In this article, the author describes what it takes to graduate from DaVita Academy, the soft skills training program dialysis services company DaVita offers all its employees. DaVita's chief executive officer, Kent Thiry, states that the Academy…

  4. 32 CFR 516.25 - DA Form 4.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC RELATIONS LITIGATION Reporting Legal Proceedings to HQDA § 516.25 DA Form 4. (a) General. The DA Form 4 (See figure...

  5. The DA{phi}NE-Light Facility

    SciTech Connect

    Burattini, Emilio; Cinque, Gianfelice; Dabagov, Sultan; Grilli, Antonio; Marcelli, Augusto; Pace, Elisabetta; Piccinini, Massimo; Raco, Agostino; Monti, Francesca

    2004-05-12

    The new Synchrotron Radiation facility at Frascati exploits the intense photon emission from DA{phi}NE, the 0,51 GeV storage ring circulating over 1 A of electrons. Among the three beamlines commissioned, the Synchrotron INfrared Beamline At Da{phi}ne (SINBAD) is fully operational by a brilliant SR beam spanning the entire IR. Recently, the soft X-ray beamline has been characterized and, once implemented the double-crystal monocromator, X-ray Absorption Spectroscopy is applied on material standards in the distinguishing energy region below 4 keV. An UltraViolet line, presently dedicated to photobiology dosimetry, has also given first results on cell irradiation in the UVB band.

  6. The Real Code of Leonardo da Vinci

    PubMed Central

    Ose, Leiv

    2008-01-01

    Leonardo da Vinci was born in Italy. Among the researchers and scientists, he is favourably known for his remarkable efforts in scientific work. His investigations of atherosclerosis judiciously combine three separate fields of research. In 1506, he finished his masterpiece, painting of Mona Lisa. A careful clinical examination of the famous painting reveals a yellow irregular leather-like spot at the inner end of the left upper eyelid and a soft bumpy well-defined swelling of the dorsum of the right hand beneath the index finger about 3 cm long. This is probably the first case of familial hypercholesterolemia (FH). The FH code of Leonardo da Vinci was given immense consideration by scientists like Carl Muller, who described the xanthomas tuberosum and angina pectoris. On the contrary, Akira Endo searched for microbial metabolites that would inhibit HMG-CoA reductase, the rate-limiting enzyme in the synthesis of cholesterol and finally, Michael Brown and Joseph Goldstein published a remarkable series of elegant and insightful papers in the 70s and 80s. They established that the cellular uptake of low-density lipoprotein (LDL) essentially requires the LDL receptor. In conclusion: this was the real Code of Leonardo da Vinci. PMID:19924278

  7. Asteroid 2012 DA14 To Whiz Past Earth Safely

    NASA Video Gallery

    The small near-Earth asteroid 2012 DA14 will pass very close to Earth on Feb. 15, 2013. Asteroid 2012 DA14 will be closest to Earth at about 11:24 a.m. PST (2:24 p.m. EST and 1924 UTC), on Feb. 15,...

  8. 40 CFR 60.52Da - Recordkeeping requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Recordkeeping requirements. 60.52Da Section 60.52Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Electric Utility Steam Generating Units for...

  9. The Case: Bunche-Da Vinci Learning Partnership Academy

    ERIC Educational Resources Information Center

    Eisenberg, Nicole; Winters, Lynn; Alkin, Marvin C.

    2005-01-01

    The Bunche-Da Vinci case described in this article presents a situation at Bunche Elementary School that four theorists were asked to address in their evaluation designs (see EJ791771, EJ719772, EJ791773, and EJ792694). The Bunche-Da Vinci Learning Partnership Academy, an elementary school located between an urban port city and a historically…

  10. Da Costa's syndrome or neurocirculatory asthenia.

    PubMed Central

    Paul, O

    1987-01-01

    The syndrome variously called Da Costa's syndrome, effort syndrome, neurocirculatory asthenia, etc has been studied for more than 100 years by many distinguished physicians. Originally identified in men in wartime, it has been widely recognised as a common chronic condition in both sexes in civilian life. Although the symptoms may seem to appear after infections and various physical and psychological stresses, neurocirculatory asthenia is most often encountered as a familial disorder that is unrelated to these factors, although they may aggravate an existing tendency. Respiratory complaints (including breathlessness, with and without effort, and smothering sensations) are almost universal, and palpitation, chest discomfort, dizziness and faintness, and fatigue are common. The physical examination is normal. The aetiology is obscure but patients usually have a normal life span. Reassurance and measures to improve physical fitness are helpful. PMID:3314950

  11. 75 FR 52292 - Airworthiness Directives; Diamond Aircraft Industries GmbH Models DA 40 and DA 40F Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-25

    ... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Diamond Aircraft... new airworthiness directive (AD) for all Diamond Aircraft Industries GmbH Models DA 40 and DA...

  12. 75 FR 75868 - Airworthiness Directives; Diamond Aircraft Industries GmbH Models DA 40 and DA 40F Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-07

    ... Register on August 25, 2010 (75 FR 52292). That NPRM proposed to require a retrofit of the rear passenger... 12866, (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034... Aircraft Industries GmbH Models DA 40 and DA 40F Airplanes AGENCY: Federal Aviation Administration,...

  13. Metal Lines in DA White Dwarfs

    NASA Astrophysics Data System (ADS)

    Zuckerman, B.; Koester, D.; Reid, I. N.; Hünsch, M.

    2003-10-01

    We report Keck telescope HIRES echelle observations of DA white dwarfs in a continuation of an extensive search for metals. These spectra are supplemented with new JHK magnitudes that are used to determine improved atmospheric parameters. Of the DA white dwarfs not in binary or common proper motion systems, about 25% show Ca II lines. For these, Ca abundances are determined from comparison with theoretical equivalent widths from model atmosphere calculations; in a few cases we also obtain Mg, Fe, Si, and Al abundances. If Ca is not observed, we generally determine very stringent upper limits. We compare the data to predictions of previously published models involving the accretion/diffusion of interstellar matter and of comets. The derived abundances are not obviously compatible with the predictions of either model, which up to now could only be tested with traces of metals in helium-rich white dwarfs. By modifying certain assumptions in the published interstellar accretion model we are able to match the distribution of the elements in the white dwarf atmospheres, but, even so, tests of other expectations from this scenario are less successful. Because comet accretion appears unlikely to be the primary cause of the DAZ phenomenon, the data suggest that no more than about 20% of F-type main-sequence stars are accompanied by Oort-like comet clouds. This represents the first observational estimate of this fraction. A plausible alternative to the accretion of cometary or interstellar matter is disruption and accretion of asteroidal material, a model first suggested in 1990 to explain excess near-infrared emission from the DAZ G29-38. An asteroidal debris model to account for the general DAZ phenomenon does not presently disagree with the HIRES data, but neither is there any compelling evidence in support of such a model. The HIRES data indicate that in close red dwarf/white dwarf binaries not known to be cataclysmic variables there is, nonetheless, significant mass

  14. Der Telemanipulator daVinci als mechanisches Trackingsystem

    NASA Astrophysics Data System (ADS)

    Käst, Johannes; Neuhaus, Jochen; Nickel, Felix; Kenngott, Hannes; Engel, Markus; Short, Elaine; Reiter, Michael; Meinzer, Hans-Peter; Maier-Hein, Lena

    Der Telemanipulator daVinci (Intuitive Surgical, Sunnyvale, Kalifornien) ist ein M aster-Slave System für roboterassistierte minimalinvasive Chirurgie. Da er über integrierte Gelenksensoren verfügt, kann er unter Verwendung der daVinci-API als mechanisches Trackingsystem verwendet werden. In dieser Arbeit evaluieren wir die Präzision und Genauigkeit eines daVinci mit Hilfe eines Genauigkeitsphantoms mit bekannten Maßen. Der ermittelte Positionierungsfehler liegt in der Größenordnung von 6 mm und ist somit für einen Großteil der medizinischen Fragestellungen zu hoch. Zur Reduktion des Fehlers schlagen wir daher eine Kalibrierung der Gelenksensoren vor.

  15. Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

    PubMed Central

    Minamino, Ryoko; Tateno, Masaki

    2014-01-01

    This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065

  16. 40 CFR 60.49Da - Emission monitoring.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... affected unit that qualifies as a gas-fired or oil-fired unit, as defined in 40 CFR 72.2, may use, as an... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Emission monitoring. 60.49Da Section 60... Generating Units § 60.49Da Emission monitoring. (a) An owner or operator of an affected facility subject...

  17. 40 CFR 60.49Da - Emission monitoring.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affected unit that qualifies as a gas-fired or oil-fired unit, as defined in 40 CFR 72.2, may use, as an... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Emission monitoring. 60.49Da Section 60... Generating Units for Which Construction is Commenced After September 18, 1978 § 60.49Da Emission...

  18. 40 CFR 60.49Da - Emission monitoring.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... affected unit that qualifies as a gas-fired or oil-fired unit, as defined in 40 CFR 72.2, may use, as an... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Emission monitoring. 60.49Da Section 60... Generating Units § 60.49Da Emission monitoring. (a) An owner or operator of an affected facility subject...

  19. Migration of ATLAS PanDA to CERN

    NASA Astrophysics Data System (ADS)

    Stewart, Graeme Andrew; Klimentov, Alexei; Koblitz, Birger; Lamanna, Massimo; Maeno, Tadashi; Nevski, Pavel; Nowak, Marcin; Emanuel De Castro Faria Salgado, Pedro; Wenaus, Torre

    2010-04-01

    The ATLAS Production and Distributed Analysis System (PanDA) is a key component of the ATLAS distributed computing infrastructure. All ATLAS production jobs, and a substantial amount of user and group analysis jobs, pass through the PanDA system, which manages their execution on the grid. PanDA also plays a key role in production task definition and the data set replication request system. PanDA has recently been migrated from Brookhaven National Laboratory (BNL) to the European Organization for Nuclear Research (CERN), a process we describe here. We discuss how the new infrastructure for PanDA, which relies heavily on services provided by CERN IT, was introduced in order to make the service as reliable as possible and to allow it to be scaled to ATLAS's increasing need for distributed computing. The migration involved changing the backend database for PanDA from MySQL to Oracle, which impacted upon the database schemas. The process by which the client code was optimised for the new database backend is discussed. We describe the procedure by which the new database infrastructure was tested and commissioned for production use. Operations during the migration had to be planned carefully to minimise disruption to ongoing ATLAS offline computing. All parts of the migration were fully tested before commissioning the new infrastructure and the gradual migration of computing resources to the new system allowed any problems of scaling to be addressed.

  20. PKC phosphorylates residues in the N-terminal of the DA transporter to regulate amphetamine-induced DA efflux.

    PubMed

    Wang, Qiang; Bubula, Nancy; Brown, Jason; Wang, Yunliang; Kondev, Veronika; Vezina, Paul

    2016-05-27

    The DA transporter (DAT), a phosphoprotein, controls extracellular dopamine (DA) levels in the central nervous system through transport or reverse transport (efflux). Multiple lines of evidence support the claim that PKC significantly contributes to amphetamine-induced DA efflux. Other signaling pathways, involving CaMKII and ERK, have also been shown to regulate DAT mediated efflux. Here we assessed the contribution of putative PKC residues (S4, S7, S13) in the N-terminal of the DAT to amphetamine-induced DA efflux by transfecting DATs containing different serine to alanine (S-A) point mutations into DA pre-loaded HEK-293 cells and incubating these cells in amphetamine (2μM). The effects of a S-A mutation at the non-PKC residue S12 and a threonine to alanine (T-A) mutation at the ERK T53 residue were also assessed for comparison. WT-DATs were used as controls. In an initial experiment, we confirmed that inhibiting PKC with Go6976 (130nM) significantly reduced amphetamine-induced DA efflux. In subsequent experiments, cells transfected with the S4A, S12A, S13A, T53A and S4,7,13A mutants showed a reduction in amphetamine-induced DA efflux similar to that observed with Go6976. Interestingly, cells transfected with the S7A mutant, identified by some as a PKC-PKA residue, showed unperturbed WT-DAT levels of amphetamine-induced DA efflux. These results indicate that phosphorylation by PKC of select residues in the DAT N-terminal can regulate amphetamine-induced efflux. PKC can act either independently or in concert with other kinases such as ERK to produce this effect. PMID:27113203

  1. Catalytic conversion of palm oil to hydrocarbons: Performance of various zeolite catalysts

    SciTech Connect

    Twaiq, F.A.; Zabidi, N.A.M.; Bhatia, S.

    1999-09-01

    The catalytic cracking of palm oil to fuels was studied in a fixed bed microreactor operated at atmospheric pressure, a reaction temperature of 350--450 C and weight hourly space velocities (WHSVs) of 1--4 h{sup {minus}1}. HZSM-5, zeolite {beta}, and ultrastable Y (USY) zeolites with different pore sizes were used to study the effects of reaction temperature and WHSV on the conversion of palm oil and yields of gasoline. The performances of HZSM-5-USY and HZSM-5-zeolite {beta} hybrid catalysts containing 10, 20, and 30 wt % HZSM-5 were investigated. Potassium-impregnated K-HZSM-5 catalysts with different potassium loadings were used to study the effect of acidity on the selectivity for gasoline formation. The major products obtained were organic liquid product (OLP), hydrocarbon gases, and water. HZSM-5 catalyst gave conversion of 99 wt % and a gasoline yield of 28 wt % at a reaction temperature of 350 C and WHSV of 1 h{sup {minus}1} and was the best among the three zeolites tested. The HZSM-5-USY hybrid catalyst performed better than USY catalyst as it resulted in a higher gasoline yield, whereas HZSM-5-zeolite {beta} hybrid catalyst gave lower conversion compared to that of zeolite {beta}. The selectivity for gasoline decreased from 45 to 10 wt % with an increase in potassium concentration from 0 to 1.5 wt %.

  2. A cosmologia no ensino da geografia

    NASA Astrophysics Data System (ADS)

    Santos, S. C.; Chiaradia, A. P. M.

    2003-08-01

    O principal objetivo deste trabalho é auxiliar o professor de Geografia em sala de aula no ensino de tópicos relacionados com a Cosmologia. A idéia deste trabalho surgiu quando foi constatado que o professor de Geografia tem dificuldades de ensinar este tópico. Esta constatação foi feita por uma das autoras ao lecionar este tópico no ensino fundamental e em discussões com outros professores de Geografia. Da mesma maneira que ocorria desde os tempos mais antigos, os alunos têm muito interesse em conhecer os fenômenos que ocorrem no Cosmo, porém os livros didáticos de Geografia utilizados em sala de aula não são ricos em informações sobre este assunto. Assim, o professor de Geografia tem poucas informações para discutir este assunto em sala de aula e não dá a devida importância para este tópico. Então, foi desenvolvido um material de apoio para professores de Geografia sobre a origem do Universo, sua evolução e seu possível futuro evolutivo segundo as mais recentes teorias, com base em perguntas feitas pelos alunos de ensino fundamental e as informações trazidas nos livros didáticos Não cabe a este material inovar e tão pouco trazer uma metodologia de ensino de Cosmologia. Neste material o professor de Geografia pode encontrará um banco de informações, que constitui no estabelecimento de conceitos, teorias e hipóteses, sobre a Cosmologia, em linguagem simples e de fácil entendimento. Para desenvolvê-lo, foram feitas pesquisas não exaustivas em livros e revistas científicas, compilação e discussão em forma cronológica das teorias aceitas sobre modelos cosmológicos. Portanto, este material será apresentado neste trabalho.

  3. Overview of ATLAS PanDA Workload Management

    NASA Astrophysics Data System (ADS)

    Maeno, T.; De, K.; Wenaus, T.; Nilsson, P.; Stewart, G. A.; Walker, R.; Stradling, A.; Caballero, J.; Potekhin, M.; Smith, D.; ATLAS Collaboration

    2011-12-01

    The Production and Distributed Analysis System (PanDA) plays a key role in the ATLAS distributed computing infrastructure. All ATLAS Monte-Carlo simulation and data reprocessing jobs pass through the PanDA system. We will describe how PanDA manages job execution on the grid using dynamic resource estimation and data replication together with intelligent brokerage in order to meet the scaling and automation requirements of ATLAS distributed computing. PanDA is also the primary ATLAS system for processing user and group analysis jobs, bringing further requirements for quick, flexible adaptation to the rapidly evolving analysis use cases of the early datataking phase, in addition to the high reliability, robustness and usability needed to provide efficient and transparent utilization of the grid for analysis users. We will describe how PanDA meets ATLAS requirements, the evolution of the system in light of operational experience, how the system has performed during the first LHC data-taking phase and plans for the future.

  4. Overview of ATLAS PanDA Workload Management

    SciTech Connect

    Maeno T.; De K.; Wenaus T.; Nilsson P.; Stewart G. A.; Walker R.; Stradling A.; Caballero J.; Potekhin M.; Smith D.

    2011-01-01

    The Production and Distributed Analysis System (PanDA) plays a key role in the ATLAS distributed computing infrastructure. All ATLAS Monte-Carlo simulation and data reprocessing jobs pass through the PanDA system. We will describe how PanDA manages job execution on the grid using dynamic resource estimation and data replication together with intelligent brokerage in order to meet the scaling and automation requirements of ATLAS distributed computing. PanDA is also the primary ATLAS system for processing user and group analysis jobs, bringing further requirements for quick, flexible adaptation to the rapidly evolving analysis use cases of the early datataking phase, in addition to the high reliability, robustness and usability needed to provide efficient and transparent utilization of the grid for analysis users. We will describe how PanDA meets ATLAS requirements, the evolution of the system in light of operational experience, how the system has performed during the first LHC data-taking phase and plans for the future.

  5. The ATLAS PanDA Monitoring System and its Evolution

    NASA Astrophysics Data System (ADS)

    Klimentov, A.; Nevski, P.; Potekhin, M.; Wenaus, T.

    2011-12-01

    The PanDA (Production and Distributed Analysis) Workload Management System is used for ATLAS distributed production and analysis worldwide. The needs of ATLAS global computing imposed challenging requirements on the design of PanDA in areas such as scalability, robustness, automation, diagnostics, and usability for both production shifters and analysis users. Through a system-wide job database, the PanDA monitor provides a comprehensive and coherent view of the system and job execution, from high level summaries to detailed drill-down job diagnostics. It is (like the rest of PanDA) an Apache-based Python application backed by Oracle. The presentation layer is HTML code generated on the fly in the Python application which is also responsible for managing database queries. However, this approach is lacking in user interface flexibility, simplicity of communication with external systems, and ease of maintenance. A decision was therefore made to migrate the PanDA monitor server to Django Web Application Framework and apply JSON/AJAX technology in the browser front end. This allows us to greatly reduce the amount of application code, separate data preparation from presentation, leverage open source for tools such as authentication and authorization mechanisms, and provide a richer and more dynamic user experience. We describe our approach, design and initial experience with the migration process.

  6. Geomagnetic observations on tristan da cunha, south atlantic ocean

    USGS Publications Warehouse

    Matzka, J.; Olsen, N.; Maule, C.F.; Pedersen, L.W.; Berarducci, A.M.; Macmillan, S.

    2009-01-01

    Few geomagnetic ground observations exist of the Earth's strongest core field anomaly, the South Atlantic Anomaly (SAA). The geomagnetic repeat station on the island Tristan da Cunha, located half-way between South Africa and South America at 37?? 05' S, 12?? 18' W, is therefore of crucial importance. We have conducted several sets of repeat station measurements during magnetically quiet conditions (Kp 2o or less) in 2004. The procedures are described and the results are compared to those from earlier campaigns and to the predictions of various global field models. Features of the local crustal bias field and the solar quiet daily variation are discussed. We also evaluate the benefit of continuous magnetic field recordings from Tristan da Cunha, and argue that such a data set is a very valuable addition to geomagnetic satellite data. Recently, funds were set up to establish and operate a magnetometer station on Tristan da Cunha during the Swarm magnetic satellite mission (2011-2014).

  7. Recent Improvements in the ATLAS PanDA Pilot

    NASA Astrophysics Data System (ADS)

    Nilsson, P.; Caballero Bejar, J.; Compostella, G.; Contreras, C.; De, K.; Dos Santos, T.; Maeno, T.; Potekhin, M.; Wenaus, T.

    2012-12-01

    The Production and Distributed Analysis system (PanDA) in the ATLAS experiment uses pilots to execute submitted jobs on the worker nodes. The pilots are designed to deal with different runtime conditions and failure scenarios, and support many storage systems. This talk will give a brief overview of the PanDA pilot system and will present major features and recent improvements including CernVM File System integration, the job retry mechanism, advanced job monitoring including JEM technology, and validation of new pilot code using the HammerCloud stress-testing system. PanDA is used for all ATLAS distributed production and is the primary system for distributed analysis. It is currently used at over 130 sites worldwide. We analyze the performance of the pilot system in processing LHC data on the OSG, EGI and Nordugrid infrastructures used by ATLAS, and describe plans for its further evolution.

  8. The role of transparency in da Vinci stereopsis.

    PubMed

    Zannoli, Marina; Mamassian, Pascal

    2011-10-15

    The majority of natural scenes contains zones that are visible to one eye only. Past studies have shown that these monocular regions can be seen at a precise depth even though there are no binocular disparities that uniquely constrain their locations in depth. In the so-called da Vinci stereopsis configuration, the monocular region is a vertical line placed next to a binocular rectangular occluder. The opacity of the occluder has been mentioned to be a necessary condition to obtain da Vinci stereopsis. However, this opacity constraint has never been empirically tested. In the present study, we tested whether da Vinci stereopsis and perceptual transparency can interact using a classical da Vinci configuration in which the opacity of the occluder varied. We used two different monocular objects: a line and a disk. We found no effect of the opacity of the occluder on the perceived depth of the monocular object. A careful analysis of the distribution of perceived depth revealed that the monocular object was perceived at a depth that increased with the distance between the object and the occluder. The analysis of the skewness of the distributions was not consistent with a double fusion explanation, favoring an implication of occlusion geometry in da Vinci stereopsis. A simple model that includes the geometry of the scene could account for the results. In summary, the mechanism responsible to locate monocular regions in depth is not sensitive to the material properties of objects, suggesting that da Vinci stereopsis is solved at relatively early stages of disparity processing. PMID:21906614

  9. Situação da Mulher na Astronomia Brasileira

    NASA Astrophysics Data System (ADS)

    Silva, Adriana V. R.

    2007-07-01

    O conteúdo desse texto surgiu de uma apresentação de mesmo título que fiz na XXXI Reunião Anual da Sociedade Astronômica Brasileira (SAB) em 2005. Esse tema foi inspirado originalmente pela minha participação no "2nd UIPAP International Conference on Women in Physics" realizado entre 23 e 25 de maio de 2005 no Rio de Janeiro. Essa é uma conferência internacional que acontece de três em três anos, sendo que a primeira ocorreu em 2002 na cidade de Paris, França. Participei dessa conferência como membro da delegação da Sociedade Brasileira de Física e um dos trabalhos que apresentei versava sobre a situação das mulheres na Astronomia brasileira, cujos resultados principais discorro a seguir. A situação das astrônomas, baseada nos dados dos sócios da SAB coletados no final de 2004, é comparada com a das físicas brasileiras e também com as nossas colegas americanas. Os dados identificam ainda uma maior evasão da carreira por parte das mulheres do que os homens. Alguns dos possíveis motivos da evasão são discutidos, como o desejo de constituir família e/ou isolamento. Resultados um tanto preocupantes com relação à distribuição de bolsas de produtividade do CNPq também são apresentados. As principais discussões e estratégias recomendadas nesse congresso são mencionadas de forma resumida ao final.

  10. The future of PanDA in ATLAS distributed computing

    NASA Astrophysics Data System (ADS)

    De, K.; Klimentov, A.; Maeno, T.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Schovancova, J.; Vaniachine, A.; Wenaus, T.

    2015-12-01

    Experiments at the Large Hadron Collider (LHC) face unprecedented computing challenges. Heterogeneous resources are distributed worldwide at hundreds of sites, thousands of physicists analyse the data remotely, the volume of processed data is beyond the exabyte scale, while data processing requires more than a few billion hours of computing usage per year. The PanDA (Production and Distributed Analysis) system was developed to meet the scale and complexity of LHC distributed computing for the ATLAS experiment. In the process, the old batch job paradigm of locally managed computing in HEP was discarded in favour of a far more automated, flexible and scalable model. The success of PanDA in ATLAS is leading to widespread adoption and testing by other experiments. PanDA is the first exascale workload management system in HEP, already operating at more than a million computing jobs per day, and processing over an exabyte of data in 2013. There are many new challenges that PanDA will face in the near future, in addition to new challenges of scale, heterogeneity and increasing user base. PanDA will need to handle rapidly changing computing infrastructure, will require factorization of code for easier deployment, will need to incorporate additional information sources including network metrics in decision making, be able to control network circuits, handle dynamically sized workload processing, provide improved visualization, and face many other challenges. In this talk we will focus on the new features, planned or recently implemented, that are relevant to the next decade of distributed computing workload management using PanDA.

  11. Publishing Planetary Data to the VO using DaCHS

    NASA Astrophysics Data System (ADS)

    Demleitner, M.

    2014-04-01

    Publishing to the Virtual Observatory has many advantages, but between standards compliance, registration, data organisation, and server operation it is also requires a nontrivial effort if starting from scratch. The DaCHS software from the German Astrophysical Virtual Observatory offers a packaged solution letting publishers concentrate on working with their own data and metadata as much as possible. For the planetary community, publishing is further facilitated by built-in support for the EPN-TAP data model. This contribution will show a typical publishing workflow together with a brief overview of how DaCHS meshes in with the VO and Web-based data usage.

  12. Asteroid 1986 DA - Radar evidence for a metallic composition

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.; Rosema, K. D.; Campbell, D. B.; Chandler, J. F.; Hine, A. A.; Hudson, R. S.

    1991-01-01

    Echoes from the near-earth object 1986 DA show it to be significantly more reflective than other radar-detected asteroids. This result supports the hypothesis that 1986 DA is a piece of NiFe metal derived from the interior of a much larger object that melted, differentiated, cooled, and subsequently was disrupted in a catastrophic collision. This 2-kilometer asteroid, which appears smooth at centimeter to meter scales but extremely irregular at 10- to 100-meter scales, might be (or have been a part of) the parent body of some iron meteorites.

  13. Identification of domains on the extrinsic 23 kDa protein possibly involved in electrostatic interaction with the extrinsic 33 kDa protein in spinach photosystem II.

    PubMed

    Tohri, Akihiko; Dohmae, Naoshi; Suzuki, Takehiro; Ohta, Hisataka; Inoue, Yasunori; Enami, Isao

    2004-03-01

    To elucidate the domains on the extrinsic 23 kDa protein involved in electrostatic interaction with the extrinsic 33 kDa protein in spinach photosystem II, we modified amino or carboxyl groups of the 23 kDa protein to uncharged methyl ester groups with N-succinimidyl propionate or glycine methyl ester in the presence of a water-soluble carbodiimide, respectively. The N-succinimidyl propionate-modified 23 kDa protein did not bind to the 33 kDa protein associated with PSII membranes, whereas the glycine methyl ester-modified 23 kDa protein completely bound. This indicates that positive charges on the 23 kDa protein are important for electrostatic interaction with the 33 kDa protein associated with the PSII membranes. Mapping of the N-succinimidyl propionate-modified sites of the 23 kDa protein was performed using Staphylococcus V8 protease digestion of the modified protein followed by determination of the mass of the resultant peptide fragments with MALDI-TOF MS. The results showed that six domains (Lys11-Lys14, Lys27-Lys38, Lys40, Lys90-Lys96, Lys143-Lys152, Lys166-Lys174) were modified with N-succinimidyl propionate. In these domains, Lys11, Lys13, Lys33, Lys38, Lys143, Lys166, Lys170 and Lys174 were wholly conserved in the 23 kDa protein from 12 species of higher plants. These positively charged lysyl residues on the 23 kDa protein may be involved in electrostatic interactions with the negatively charged carboxyl groups on the 33 kDa protein, the latter has been suggested to be important for the 23 kDa binding [Bricker, T.M. & Frankel, L.K. (2003) Biochemistry42, 2056-2061]. PMID:15009208

  14. 40 CFR 60.45Da - Standard for mercury (Hg).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for mercury (Hg). 60.45Da... for mercury (Hg). (a) For each coal-fired electric utility steam generating unit other than an IGCC... gases that contain mercury (Hg) emissions in excess of each Hg emissions limit in paragraphs...

  15. Training and Health. Leonardo da Vinci Series: Good Practices.

    ERIC Educational Resources Information Center

    Commission of the European Communities, Brussels (Belgium). Directorate-General for Education and Culture.

    This document profiles programs in the fields of health and medicine that are offered through the European Commission's Leonardo da Vinci program. The following programs are profiled: (1) CYTOTRAIN (a transnational vocational training program in cervical cancer screening); (2) Apollo (a program of open and distance learning for paramedical…

  16. The DaVinci Project: Multimedia in Art and Chemistry.

    ERIC Educational Resources Information Center

    Simonson, Michael; Schlosser, Charles

    1998-01-01

    Provides an overview of the DaVinci Project, a collaboration of students, teachers, and researchers in chemistry and art to develop multimedia materials for grades 3-12 visualizing basic concepts in chemistry and visual art. Topics addressed include standards in art and science; the conceptual framework for the project; and project goals,…

  17. The Potential da Vinci in All of Us

    ERIC Educational Resources Information Center

    Petto, Sarah; Petto, Andrew

    2009-01-01

    The study of the human form is fundamental to both science and art curricula. For vertebrates, perhaps no feature is more important than the skeleton to determine observable form and function. As Leonard da Vinci's famous Proportions of the Human Figure (Virtruvian Man) illustrates, the size, shape, and proportions of the human body are defined by…

  18. DATA ASSESSMENT REPORTS FOR CEMS AT SUBPART DA FACILITIES

    EPA Science Inventory

    EPA promulgated minimum quality assurance (QA) requirements for Continuous Emission Monitoring Systems (CEMS) in 40 CFR Part 60 Appendix F. Appendix F requires Da source owners to develop site-specific QA plans and report the results of EPA specified QA activities each calendar q...

  19. Asteroid 1986 DA: Radar evidence for a metallic composition

    NASA Technical Reports Server (NTRS)

    Ostro, Steven J.; Campbell, D. B.; Chandler, J. F.; Hine, A. A.; Hudson, R. S.; Rosema, K. D.; Shapiro, Irwin I.

    1991-01-01

    Radar observations of the near-Earth asteroid 1986 DA were carried out at the Arecibo Observatory in April 1986, two months after its discovery. Radar results are consistent with the hypothesis that 1986 HA is a piece of NiFe metal derived from the interior of a much larger object that melted, differentiated, cooled and subsequently was disrupted in a catastrophic collision. This 2-km asteroid might be (or have been part of) the parent body of some iron meteorites. Or 1986 DA might share the parentage and/or part of the dynamical history of some meteorites without ever having contributed any of its own ejecta to our meteorite sample. Analysis of the samples returned from 1986 DA might ultimately involve economic considerations. Meteoritic metal is mostly iron with about 8 percent nickel, but also contains substantial concentrations of precious and strategic metals, including approx. 1 ppm of gold and approx. 10 ppm of platinum group elements. If these abundances apply to 1986 DA, it contains some 10(exp 16) g of iron, 10 (exp 15) g of nickel, 10(exp 11) g of platinum group metals, and 10(exp 10) g of gold.

  20. 40 CFR 60.47Da - Commercial demonstration permit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... potential combustion concentration (80 percent reduction) for each 24-hour period of steam generator... owner or operator of a fluidized bed combustion electric utility steam generator (atmospheric or... Steam Generating Units for Which Construction is Commenced After September 18, 1978 § 60.47Da...

  1. 40 CFR 60.47Da - Commercial demonstration permit.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... potential combustion concentration (80 percent reduction) for each 24-hour period of steam generator... owner or operator of a fluidized bed combustion electric utility steam generator (atmospheric or... Steam Generating Units for Which Construction is Commenced After September 18, 1978 § 60.47Da...

  2. Women and Technical Professions. Leonardo da Vinci Series: Good Practices.

    ERIC Educational Resources Information Center

    Commission of the European Communities, Brussels (Belgium). Directorate-General for Education and Culture.

    This document profiles programs for women in technical professions that are offered through the European Commission's Leonardo da Vinci program. The following programs are profiled: (1) Artemis and Diana (vocational guidance programs to help direct girls toward technology-related careers); (2) CEEWIT (an Internet-based information and…

  3. Studying and Working Abroad. Leonardo da Vinci Series: Good Practices.

    ERIC Educational Resources Information Center

    Commission of the European Communities, Brussels (Belgium). Directorate-General for Education and Culture.

    This document profiles recent successful examples of students studying and working abroad as part of the European Commission's Leonardo da Vinci program, which is designed to give students across the European Union the opportunity to experience vocational training in a foreign country. The following examples are presented: (1) 3 Finnish students…

  4. Modelagem do vento e da fotosfera de AG Carinae

    NASA Astrophysics Data System (ADS)

    Groh, J. H.; Damineli, A.

    2003-08-01

    A trajetória evolutiva das estrelas de alta massa depende fortemente de suas taxas de perda de massa. Apesar do rápido progresso no estudo destas estrelas, a taxa de perda de massa e outros parâmetros físicos básicos, como a temperatura superficial e a velocidade terminal do vento ainda não estão bem determinados. Isto ocorre devido à presença de ventos irregulares, rápidos e fortes ao redor destas estrelas, tornando a interpretação dos seus espectros uma tarefa difícil. Assim, a modelagem do vento e da fotosfera dessas estrelas está sendo cada vez mais usada para obter tais parâmetros a partir dos espectros. O aumento da taxa de perda de massa durante a fase LBV (Variáveis Luminosas Azuis), comparado com outros tipos de estrelas, tem sido atribuído a instabilidades do tipo S Doradus. Dispomos de uma base de dados espectroscópicos cobrindo 22 anos de observações de AG Carinae, incluindo um ciclo S Doradus completo, com espectros CCD em alta resolução na faixa óptica e infravermelha. Utilizamos o programa desenvolvido por Schmutz (1997) para uma análise preliminar desse ciclo, obtendo a taxa de perda de massa a partir da linha do Ha. Não existe uma correlação clara da taxa de perda de massa com mudanças da temperatura efetiva, do raio da estrela e do fluxo na banda V. A estrela atingiu seu mínimo fotométrico (raio mínimo) em 1990 e o máximo fotométrico (raio máximo) em 1995, enquanto que o fluxo máximo da linha do Ha ocorreu em 1996. Além disso a taxa de perda de massa não segue esse ciclo, contrariamente às idéias correntes. Para fazer um modelo mais realista estamos usando o programa CMFGEN (Hillier & Miller), que trata a fotosfera e o vento estelar de forma consistente, considerando a radiação fora do equilíbrio termodinâmico (NLTE) e com blanketting total de linhas. Simulamos o espectro de AG Carinae em duas épocas extremas do ciclo S Dor para testar os resultados obtidos com o modelo mais simplificado.

  5. 49 CFR 178.58 - Specification 4DA welded steel cylinders for aircraft use.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Specification 4DA welded steel cylinders for...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.58 Specification 4DA welded steel cylinders for aircraft use. (a) Type, size, and service pressure. A DOT 4DA is a welded steel sphere (two...

  6. 49 CFR 178.58 - Specification 4DA welded steel cylinders for aircraft use.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Specification 4DA welded steel cylinders for...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.58 Specification 4DA welded steel cylinders for aircraft use. (a) Type, size, and service pressure. A DOT 4DA is a welded steel sphere (two...

  7. In vivo breakdown products of the 32 kDa thylakoid herbicide binding protein. [Spirodela oligorrhiza

    SciTech Connect

    Greenberg, B.M.; Mattoo, A.K.; Gaba, V.; Edelman, M.

    1986-04-01

    The 32 kDa herbicide binding protein of PSII is degraded rapidly in the light. This phenomenon was investigated in Spirodela oligorrhiza. When fronds were radiolabeled in the presence of cycloheximide only the chloroplast-encoded proteins were labeled. Under these conditions, a breakdown product of 23.5 kDa was observed. This polypeptide was further degraded with kinetics similar to that of the 32 kDa protein. The 23.5 kDa polypeptide cross-reacted with an antibody specific to the 32 kDa protein. By protease digestion it was determined that the 23.5 kDa polypeptide is the intact N-terminal piece of the 32 kDa protein. Thus, this product corresponds to the membrane anchor of the 32 kDa protein. Using the same antibody, breakdown products of 16 kDa, 14 kDa and 12 kDa were observed. These products have also been observed in Zea mays and Solanum nigrum. Using DCMU during pulse-chase experiments at different light intensities, evidence was obtained that the 23.5 kDa breakdown product is generated in vivo.

  8. Roles and Delegation of Authority (R/DA) System

    SciTech Connect

    ABBOTT,JOHN P.; HUTCHINS,JAMES C.; SCHOCH,DAVID G.

    1999-11-01

    The processes of defining managerial roles and providing for delegation of authority are essential to any enterprise. At most large organizations, these processes are defined in policy manuals and through sets of standard operating procedures for many, if not all, business and administrative functions. Many of these staff-initiated, administrative functions require the routing of documents for approval to one or more levels of management. These employee-oriented, back office types of workflows tend to require more flexibility in determining to whom these documents should go to, while, at the same time, providing the responsible parties with the flexibility to delegate their approval authority or allow others to review their work. Although this practice is commonplace in manual, paper-based processes that exist in many organizations, it is difficult to provide the same flexibility in the more structured, electronic-based, workflow systems. The purpose of this report is to present a framework or architecture for creating a R/DA system and provide some insights associated with its design and utilization. To improve understanding and clarify subsequent discussion, the goals and requirements for the major R/DA system components, namely, the database and interface modules, are initially presented along with the identification of important concepts and the definition of critical terms. Next high-level functions relating the types of inputs to the outputs of the R/DA interface module are introduced and discussed. Then the relationships between the major R/DA modules and the primary components associated with its creation and maintenance are presented and analyzed. Finally, some conclusions are drawn relative to the advantages associated with developing a R/DA system for use in implementing an enterprise-wide, work-facilitating information system.

  9. JCoDA: a tool for detecting evolutionary selection

    PubMed Central

    2010-01-01

    Background The incorporation of annotated sequence information from multiple related species in commonly used databases (Ensembl, Flybase, Saccharomyces Genome Database, Wormbase, etc.) has increased dramatically over the last few years. This influx of information has provided a considerable amount of raw material for evaluation of evolutionary relationships. To aid in the process, we have developed JCoDA (Java Codon Delimited Alignment) as a simple-to-use visualization tool for the detection of site specific and regional positive/negative evolutionary selection amongst homologous coding sequences. Results JCoDA accepts user-inputted unaligned or pre-aligned coding sequences, performs a codon-delimited alignment using ClustalW, and determines the dN/dS calculations using PAML (Phylogenetic Analysis Using Maximum Likelihood, yn00 and codeml) in order to identify regions and sites under evolutionary selection. The JCoDA package includes a graphical interface for Phylip (Phylogeny Inference Package) to generate phylogenetic trees, manages formatting of all required file types, and streamlines passage of information between underlying programs. The raw data are output to user configurable graphs with sliding window options for straightforward visualization of pairwise or gene family comparisons. Additionally, codon-delimited alignments are output in a variety of common formats and all dN/dS calculations can be output in comma-separated value (CSV) format for downstream analysis. To illustrate the types of analyses that are facilitated by JCoDA, we have taken advantage of the well studied sex determination pathway in nematodes as well as the extensive sequence information available to identify genes under positive selection, examples of regional positive selection, and differences in selection based on the role of genes in the sex determination pathway. Conclusions JCoDA is a configurable, open source, user-friendly visualization tool for performing evolutionary

  10. [Lobectomy for lung cancer using the Da Vinci surgical system].

    PubMed

    Nakamura, Hiroshige

    2014-05-01

    Robot-assisted surgery using the da Vinci surgical system has attracted attention because of excellent operability without shaking by joint forceps under the clear vision of a three-dimensional high-definition camera in lung cancer surgery. Although this form of advanced medical care is not yet approved for insurance coverage, it is at the stage of clinical research and expected to be useful in hilar exposure, lymph node dissection, and suturing of the lung parenchyma or bronchus. Lung cancer surgery with the da Vinci system has the advantage of combining thoracotomy and minimally invasive surgery in video-assisted thoracic surgery. However, safety management, education, and significant cost are problems to be resolved. Several important issues such as sharing knowledge and technology of robotic surgery, education, training, development of new instruments, and acquisition of advanced medical insurance are discussed for the future development of robotic surgical systems. PMID:24946522

  11. DaVinci's Mona Lisa entering the next dimension.

    PubMed

    Carbon, Claus-Christian; Hesslinger, Vera M

    2013-01-01

    For several of Leonardo da Vinci's paintings, such as The Virgin and Child with St Anne or the Mona Lisa, there exist copies produced by his own studio. In case of the Mona Lisa, a quite exceptional, rediscovered studio copy was presented to the public in 2012 by the Prado Museum in Madrid. Not only does it mirror its famous counterpart superficially; it also features the very same corrections to the lower layers, which indicates that da Vinci and the 'copyist' must have elaborated their panels simultaneously. On the basis of subjective (thirty-two participants estimated painter-model constellations) as well as objective data (analysis of trajectories between landmarks of both paintings), we revealed that both versions differ slightly in perspective. We reconstructed the original studio setting and found evidence that the disparity between both paintings mimics human binocular disparity. This points to the possibility that the two Giocondas together might represent the first stereoscopic image in world history. PMID:24303752

  12. TA-DA: A TOOL FOR ASTROPHYSICAL DATA ANALYSIS

    SciTech Connect

    Da Rio, Nicola; Robberto, Massimo

    2012-12-01

    We present the Tool for Astrophysical Data Analysis (TA-DA), a new software aimed to greatly simplify and improve the analysis of stellar photometric data in comparison with theoretical models, and allow the derivation of stellar parameters from multi-band photometry. Its flexibility allows one to address a number of such problems: from the interpolation of stellar models, or sets of stellar physical parameters in general, to the computation of synthetic photometry in arbitrary filters or units; from the analysis of observed color-magnitude diagrams to a Bayesian derivation of stellar parameters (and extinction) based on multi-band data. TA-DA is available as a pre-compiled Interactive Data Language widget-based application; its graphical user interface makes it considerably user-friendly. In this paper, we describe the software and its functionalities.

  13. The Da Vinci code dynamically de-coded.

    PubMed

    Cohen, Mariam

    2005-01-01

    The novel The Da Vinci Code, by Dan Brown has been on best-seller lists for over two years. An examination of Brown's previous novels reveals a well-designed plot line shared by all four novels that not only makes them good "thrillers" but also creates a mythological structure to the novels that draws on common unconscious fantasies in the same way that fairy tales do. One aspect of this mythological structure is the use of evil conspiracies (and benign ones as well) for the protagonist to overcome. In addition, The Da Vinci Code presents a religious theme involving legends about Mary Magdalene. This theme touches on the role of a feminine aspect to divinity in allowing for an erotic connection with the divine. PMID:16448349

  14. The da Vinci robot in right adrenalectomy: considerations on technique.

    PubMed

    D'Annibale, Annibale; Fiscon, Valentino; Trevisan, Paolo; Pozzobon, Maurizia; Gianfreda, Valeria; Sovernigo, Gianna; Morpurgo, Emilio; Orsini, Camillo; Del Monte, Daniele

    2004-02-01

    The da Vinci Robotic System (Intuitive Surgical, Mountain View, CA) became available at the General Surgery Department of Camposampiero Hospital in May 2001. From May 2001 to October 2002, 139 robotic operations were performed, one of which was a right adrenalectomy for a right adrenal mass. The progressive growth of the mass was the indication for surgical excision. Surgical adrenalectomy was successfully completed with da Vinci Robotic System using 5 ports (3 for the robotic system, 2 as service trocars). The wrist-like movements of the instrument's tip easily enabled the detachment of the right hepatic lobe from the gland and vessel isolation, while the 3-dimensional vision facilitated dissection of the veins from the vena cava. PMID:15259586

  15. PanDaTox: a tool for accelerated metabolic engineering

    SciTech Connect

    Amitai, Gil; Sorek, Rotem

    2012-04-18

    Metabolic engineering is often facilitated by cloning of genes encoding enzymes from various heterologous organisms into E. coli. Such engineering efforts are frequently hampered by foreign genes that are toxic to the E. coli host. We have developed PanDaTox (www.weizmann.ac.il/pandatox), a web-based resource that provides experimental toxicity information for more than 1.5 million genes from hundreds of different microbial genomes. The toxicity predictions, which were extensively experimentally verified, are based on serial cloning of genes into E. coli as part of the Sanger whole genome shotgun sequencing process. PanDaTox can accelerate metabolic engineering projects by allowing researchers to exclude toxic genes from the engineering plan and verify the clonability of selected genes before the actual metabolic engineering experiments are conducted.

  16. Improving Security in the ATLAS PanDA System

    NASA Astrophysics Data System (ADS)

    Caballero, J.; Maeno, T.; Nilsson, P.; Stewart, G.; Potekhin, M.; Wenaus, T.

    2011-12-01

    The security challenges faced by users of the grid are considerably different to those faced in previous environments. The adoption of pilot jobs systems by LHC experiments has mitigated many of the problems associated with the inhomogeneities found on the grid and has greatly improved job reliability; however, pilot jobs systems themselves must then address many security issues, including the execution of multiple users' code under a common 'grid' identity. In this paper we describe the improvements and evolution of the security model in the ATLAS PanDA (Production and Distributed Analysis) system. We describe the security in the PanDA server which is in place to ensure that only authorized members of the VO are allowed to submit work into the system and that jobs are properly audited and monitored. We discuss the security in place between the pilot code itself and the PanDA server, ensuring that only properly authenticated workload is delivered to the pilot for execution. When the code to be executed is from a 'normal' ATLAS user, as opposed to the production system or other privileged actor, then the pilot may use an EGEE developed identity switching tool called gLExec. This changes the grid proxy available to the job and also switches the UNIX user identity to protect the privileges of the pilot code proxy. We describe the problems in using this system and how they are overcome. Finally, we discuss security drills which have been run using PanDA and show how these improved our operational security procedures.

  17. 40 CFR 60.49Da - Emission monitoring.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... defined in 40 CFR 72.2, may use, as an alternative to the requirements specified in either paragraph (l... § 60.58b(i)(3) of subpart Eb of this part. (ii) Each 1-hour CO emissions average is calculated using... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Emission monitoring. 60.49Da Section...

  18. 40 CFR 60.49Da - Emission monitoring.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... affected unit that qualifies as a gas-fired or oil-fired unit, as defined in 40 CFR 72.2, may use, as an... § 60.58b(i)(3) of subpart Eb of this part. (ii) Each 1-hour CO emissions average is calculated using... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Emission monitoring. 60.49Da Section...

  19. Surgical treatment of parietal defects with "da Vinci" surgical robot.

    PubMed

    Vasilescu, D; Paun, S

    2012-06-12

    The robotic surgery has come through the development of telemedicine and minimally invasive surgery concepts, being developed in the military medicine by NASA during the years 1970-1980. The purpose of this paper is to briefly present our experience in the new field of the robotic surgery, by analyzing the results obtained over a lot of 20 patients operated with the "da Vinci" robot within the last 5 years in the Clinical Emergency Hospital Bucharest for various abdominal defects. PMID:22802899

  20. Identification of an abundant 56 kDa protein implicated in food allergy as granule-bound starch synthase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice, the staple food of South and East Asian counties, is considered to be hypoallergenic. However, several clinical studies have documented rice-induced allergy in sensitive patients. Rice proteins with molecular weights of 14-16 kDa, 26 kDa, 33 kDa and 56 kDa have been identified as allergens. Re...

  1. The ATLAS PanDA Pilot in Operation

    NASA Astrophysics Data System (ADS)

    Nilsson, P.; Caballero, J.; De, K.; Maeno, T.; Stradling, A.; Wenaus, T.; ATLAS Collaboration

    2011-12-01

    The Production and Distributed Analysis system (PanDA) [1-2] was designed to meet ATLAS [3] requirements for a data-driven workload management system capable of operating at LHC data processing scale. Submitted jobs are executed on worker nodes by pilot jobs sent to the grid sites by pilot factories. This paper provides an overview of the PanDA pilot [4] system and presents major features added in light of recent operational experience, including multi-job processing, advanced job recovery for jobs with output storage failures, gLExec [5-6] based identity switching from the generic pilot to the actual user, and other security measures. The PanDA system serves all ATLAS distributed processing and is the primary system for distributed analysis; it is currently used at over 100 sites worldwide. We analyze the performance of the pilot system in processing real LHC data on the OSG [7], EGI [8] and Nordugrid [9-10] infrastructures used by ATLAS, and describe plans for its evolution.

  2. Common commercial cosmetic products induce arthritis in the DA rat.

    PubMed Central

    Sverdrup, B; Klareskog, L; Kleinau, S

    1998-01-01

    Many different agents, including mineral oil and silicone, have the capacity to act as immunological adjuvants, i.e., they can contribute to the activation of the immune system. Some adjuvants, including mineral oil, are known to induce arthritis in certain strains of rats after intradermal injection or percutaneous application. The aim of this study was to determine if common commercial cosmetic products containing mineral oil could induce arthritis in the highly susceptible DA (Dark Agouti) rat. Intradermal injection of five out of eight assayed cosmetic products without further additives resulted in arthritis with synovitis. One of the products induced a very aggressive arthritis, which had declined after 5-9 weeks. When this product was also assayed for arthritogenicity upon percutaneous administration, it induced a mild and transient arthritis in 5 out of 10 DA rats, whereas control animals showed no clinical signs of joint involvement. No arthritic reaction was seen in rats after peroral feeding with the most arthritogenic product or by intravaginal application of Freund's adjuvants. Silicone gel implants in DA rats did not cause arthritis. We conclude that mineral oils included in common commercially available products retain their adjuvant properties and are arthritogenic in the presently investigated arthritis-prone rat strain. There is yet no evidence that mineral oils present in cosmetics may contribute to arthritis in humans, but we suggest that this question should be subject to further investigation. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:9417771

  3. OpenDA-NEMO framework for ocean data assimilation

    NASA Astrophysics Data System (ADS)

    van Velzen, Nils; Altaf, Muhammad Umer; Verlaan, Martin

    2016-03-01

    Data assimilation methods provide a means to handle the modeling errors and uncertainties in sophisticated ocean models. In this study, we have created an OpenDA-NEMO framework unlocking the data assimilation tools available in OpenDA for use with NEMO models. This includes data assimilation methods, automatic parallelization, and a recently implemented automatic localization algorithm that removes spurious correlations in the model based on uncertainties in the computed Kalman gain matrix. We have set up a twin experiment where we assimilate sea surface height (SSH) satellite measurements. From the experiments, we can conclude that the OpenDA-NEMO framework performs as expected and that the automatic localization significantly improves the performance of the data assimilation algorithm by successfully removing spurious correlations. Based on these results, it looks promising to extend the framework with new kinds of observations and work on improving the computational speed of the automatic localization technique such that it becomes feasible to include large number of observations.

  4. Amelioration of Auditory Response by DA9801 in Diabetic Mouse

    PubMed Central

    Hong, Bin Na; Her, You Ri; Castañeda, Rodrigo; Moon, Hyo Won

    2015-01-01

    Diabetes mellitus (DM) is a metabolic disease that involves disorders such as diabetic retinopathy, diabetic neuropathy, and diabetic hearing loss. Recently, neurotrophin has become a treatment target that has shown to be an attractive alternative in recovering auditory function altered by DM. The aim of this study was to evaluate the effect of DA9801, a mixture of Dioscorea nipponica and Dioscorea japonica extracts, in the auditory function damage produced in a STZ-induced diabetic model and to provide evidence of the mechanisms involved in enhancing these protective effects. We found a potential application of DA9801 on hearing impairment in the STZ-induced diabetic model, demonstrated by reducing the deterioration produced by DM in ABR threshold in response to clicks and normalizing wave I–IV latencies and Pa latencies in AMLR. We also show evidence that these effects might be elicited by inducing NGF related through Nr3c1 and Akt. Therefore, this result suggests that the neuroprotective effects of DA9801 on the auditory damage produced by DM may be affected by NGF increase resulting from Nr3c1 via Akt transformation. PMID:25878713

  5. Amelioration of Auditory Response by DA9801 in Diabetic Mouse.

    PubMed

    Lee, Yeong Ro; Hong, Bin Na; Her, You Ri; Castañeda, Rodrigo; Moon, Hyo Won; Kang, Tong Ho

    2015-01-01

    Diabetes mellitus (DM) is a metabolic disease that involves disorders such as diabetic retinopathy, diabetic neuropathy, and diabetic hearing loss. Recently, neurotrophin has become a treatment target that has shown to be an attractive alternative in recovering auditory function altered by DM. The aim of this study was to evaluate the effect of DA9801, a mixture of Dioscorea nipponica and Dioscorea japonica extracts, in the auditory function damage produced in a STZ-induced diabetic model and to provide evidence of the mechanisms involved in enhancing these protective effects. We found a potential application of DA9801 on hearing impairment in the STZ-induced diabetic model, demonstrated by reducing the deterioration produced by DM in ABR threshold in response to clicks and normalizing wave I-IV latencies and Pa latencies in AMLR. We also show evidence that these effects might be elicited by inducing NGF related through Nr3c1 and Akt. Therefore, this result suggests that the neuroprotective effects of DA9801 on the auditory damage produced by DM may be affected by NGF increase resulting from Nr3c1 via Akt transformation. PMID:25878713

  6. OpenDA-NEMO framework for ocean data assimilation

    NASA Astrophysics Data System (ADS)

    van Velzen, Nils; Altaf, Muhammad Umer; Verlaan, Martin

    2016-05-01

    Data assimilation methods provide a means to handle the modeling errors and uncertainties in sophisticated ocean models. In this study, we have created an OpenDA-NEMO framework unlocking the data assimilation tools available in OpenDA for use with NEMO models. This includes data assimilation methods, automatic parallelization, and a recently implemented automatic localization algorithm that removes spurious correlations in the model based on uncertainties in the computed Kalman gain matrix. We have set up a twin experiment where we assimilate sea surface height (SSH) satellite measurements. From the experiments, we can conclude that the OpenDA-NEMO framework performs as expected and that the automatic localization significantly improves the performance of the data assimilation algorithm by successfully removing spurious correlations. Based on these results, it looks promising to extend the framework with new kinds of observations and work on improving the computational speed of the automatic localization technique such that it becomes feasible to include large number of observations.

  7. Basic principles of pharmaceutical science in Ayurvĕda.

    PubMed

    Subhose, Varanasi; Srinivas, Pitta; Narayana, Ala

    2005-01-01

    Pharmaceutical is one of the allied branches of science, which is closely associated with Medical science. Today pharmaceutical chemistry and pharmacognosy are playing important role in treatment for a disease and its prevention. Herbal medicines are being used by about 80% of the world population mostly in the developing countries in the primary health care. There has been an upsurge in demand for the Phyto-pharmaceutical products of Ayurvĕda in western nations, because of the fact that the synthetic drugs are considered to be unsafe. Due to this many national and multinational pharmaceutical companies are now concentrating on manufacturing of Ayurvĕdic Phyto-pharmaceutical products. Ayurvĕda is the Indian traditional system of medicine, which also deals about pharmaceutical science. The Ayurvĕdic knowledge of the pharmaceutical science is scattered in Ayurvĕdic classical texts. Săranghadhara Samhita, which is written by Săranghadhara, explain systematically about the information of the Ayurvĕdic pharmaceutical science and also updated it. Industrialized manufacturing of Ayurvĕdic dosage forms has brought in new challenges like deviation from basic concepts of medicine preparation. Săranghadhara Samrhită the devout text on pharmaceutics in Ayurvĕda comes handy to solve such problems, as the methods described are very lucid and easy to follow. PMID:17333665

  8. Seeking 'energy' vs. pain relief in spas in Brazil (Caldas da Imperatriz) and Portugal (Termas da Sulfurea).

    PubMed

    Quintela, Maria Manuel

    2011-04-01

    This paper is a comparative ethnography of the therapeutic practices at two different spa locations: Caldas da Imperatriz, SC, Brazil, and Termas da Sulfurea in Cabeco de Vide, Portugal. The comparison reveals the existence of contrasting 'explanatory models' held by the spa-goers as well as by the official medical systems. In the Portuguese context this model is highly medicalized; in the Brazilian case, spa treatments are viewed as 'alternative' or 'complementary' therapy and are also related to religious philosophies. Each model corresponds to a different idiom expressing certain experiences and world views, one focusing on 'pains' (dores) and the other on 'energy' (energia), the former leading to the rationale of 'curing', the latter to the notion of 'energizing'. In this paper the author intends to analyze and contrast the categories found in these models, which originate from different conceptions of health, illness and healing for Brazilian and Portuguese spa-goers. PMID:21563001

  9. [The Arabic influence in the "Colóquios dos simples e drogas da India" of Garcia da Orta].

    PubMed

    Ricordel, Joëlle

    2015-09-01

    The "Colóquios dos simples e drogas he cousas medicinais de Índia" (Conversations on the simples, drugs and medicinal substances of India) (1563) of Garcia da Orta is a botanical and pharmacognosy book. The author is a Portuguese physician who studied in the Spanish universities and practiced medicine mainly in India. He studies in short chapters presented in the form of dialogues about sixty simples. Sources to which he refers are indicative of a "classical" training, but also the mark of a curious and open mind to different cultures. The Arabic sources are numerous and mainly concern the identification of substances by abundant synonyms of their names in foreign languages and different medicinal uses that may have been done by the ancient physicians. However, Da Orta is critical with respect to these sources, seeking contradictions and differences of opinion among authors. He confronts them with the oral information collected thanks to a wide network of contacts. PMID:26529894

  10. The 29-kDa proteins phosphorylated ion thrombin-activated human platelets are forms of the estrogen receptor-related 27-kDa heat shock protein

    SciTech Connect

    Mendelsohn, M.E.; Yan Zhu; O'Neill, S. )

    1991-12-15

    Thrombin plays a critical role in platelet activation, hemostasis, and thrombosis. Cellular activation by thrombin leads to the phosphorylation of multiple proteins, most of which are unidentified. The authors have characterized several 29-kDa proteins that are rapidly phosphorylated following exposure of intact human platelets to thrombin. A murine monoclonal antibody raised to an unidentified estrogen receptor-related 29-kDa protein selectively recognized these proteins as well as a more basic, unphosphorylated 27-kDa protein. Cellular activation by thrombin led to a marked shift in the proportion of protein from the 27-kDa unphosphorylated form to the 29-kDa phosphoprotein species. Using this antibody, they isolated and sequenced a human cDNA clone encoding a protein that was identical to the mammalian 27-kDa heat shock protein (HSP27), a protein of uncertain function that is known to be phosphorylated to several forms and to be transcriptionally induced by estrogen. The 29-kDa proteins were confirmed to be phosphorylated forms of HSP27 by immunoprecipitation studies. Thus, the estrogen receptor-related protein is HSP27, and the three major 20-kDa proteins phosphorylated in thrombin-activated platelets are forms of HSP27. These data suggest a role for HSP27 in the signal transduction events of platelet activation.

  11. Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

    NASA Astrophysics Data System (ADS)

    Zhao, Na; Li, Siwen; Wang, Jinyi; Zhang, Ronglan; Gao, Ruimin; Zhao, Jianshe; Wang, Junlong

    2015-05-01

    M2(PcAN)2 (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M2(PcAN)2-W-HZSM-5) or the M2(PcTN)2 doping W-HZSM-5 (M2(PcTN)2/W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu2(PcAN)2-W-HZSM-5 and Cu2(PcTN)2/W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV-Vis and calcination temperature was obtained by TG-DSC for Cu2(PcTN)2/W-HZSM-5. Catalysts were characterized by EA, IR, XRD, SEM, TEM, ICP, and N2 adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed.

  12. Identification of sequence similarity between 60 kDa and 70 kDa molecular chaperones: evidence for a common evolutionary background?

    PubMed Central

    Flores, A I; Cuezva, J M

    1997-01-01

    Recent findings support the premise that chaperonins (60 kDa stress-proteins) and alpha-subunits of F-type ATPases (alpha-ATPase) are evolutionary related protein families. Two-dimensional gel patterns of synthesized proteins in unstressed and heat-shocked embryonic Drosophila melanogaster SL2 cells revealed that antibodies raised against the alpha-subunit of the F1-ATPase complex from rat liver recognize an inducible p71 member of the 70 kDa stress-responsive protein family. Molecular recognition of this stress-responsive 70 kDa protein by antibodies raised against the F1-ATPase alpha-subunit suggests the possibility of partial sequence similarity within these ATP-binding protein families. A multiple sequence alignment between alpha-ATPases and 60 kDa and 70 kDa molecular chaperones is presented. Statistical evaluation of sequence similarity reveals a significant degree of sequence conservation within the three protein families. The finding suggests a common evolutionary origin for the ATPases and molecular chaperone protein families of 60 kDa and 70 kDa, despite the lack of obvious structural resemblance between them. PMID:9065788

  13. Da Vinci's codex and the anatomy of healthcare.

    PubMed

    Stephens-Borg, Keith

    2012-08-01

    We usually display a laid-back approach to medical jargon throughout our theatre work. The word 'perioperative' is built from the Greek word 'peri' (around) and the Latin 'operari' (to work). Latin and Greek became the prefixed language of choice for Leonardo da Vinci, and his research was pivotal in determining the way in which surgical procedures are documented. Ancient manuscripts aided the unfolding of the secrets of anatomy, and Leonardo revealed that art was the key in expressive detailed explanation. PMID:23248927

  14. Stereoscopic augmented reality for da Vincii™ robotic biliary surgery

    PubMed Central

    Volonté, Francesco; Buchs, Nicolas C.; Pugin, François; Spaltenstein, Joël; Jung, Minoa; Ratib, Osman; Morel, Philippe

    2013-01-01

    INTRODUCTION New laparoscopic techniques put distance between the surgeon and his patient. PRESENTATION OF CASE 3D volume rendered images directly displayed in the da Vinci surgeon's console fill this gap by allowing the surgeon to fully immerse in its intervention. DISCUSSION During the robotic operation the surgeon has a greater control on the procedure because he can stay more focused not being obliged to turn is sight out of his operative field. Moreover, thanks to depth perception of the rendered images he had a precise view of important anatomical structures. CONCLUSION We describe our preliminary experience in the quest of computer-assisted robotic surgery. PMID:23466685

  15. Ultratight crystal packing of a 10 kDa protein

    SciTech Connect

    Trillo-Muyo, Sergio; Chruszcz, Maksymilian; Minor, Wladek; Kuisiene, Nomeda

    2013-03-01

    The crystal structure of the C-terminal domain of a putative U32 peptidase from G. thermoleovorans is reported; it is one of the most tightly packed protein structures reported to date. While small organic molecules generally crystallize forming tightly packed lattices with little solvent content, proteins form air-sensitive high-solvent-content crystals. Here, the crystallization and full structure analysis of a novel recombinant 10 kDa protein corresponding to the C-terminal domain of a putative U32 peptidase are reported. The orthorhombic crystal contained only 24.5% solvent and is therefore among the most tightly packed protein lattices ever reported.

  16. A quasi-passive CMOS pipeline D/A converter

    NASA Technical Reports Server (NTRS)

    Wang, Fong-Jim; Temes, Gabor C.; Law, Simon

    1989-01-01

    A novel pipeline digital-to-analog converter configuration, based on switched-capacitor techniques, is described. An n-bit D/A conversion can be implemented by cascading n + 1 unit cells. The device count of the circuit increases linearly, not exponentially, with the conversion accuracy. The new configuration can be pipelined. Hence, the conversion rate can be increased without requiring a higher clock rate. An experimental 10-bit DAC prototype has been fabricated using a 3-micron CMOS process. The results show that high-speed, high-accuracy, and low-power operation can be achieved without special process or postprocess trimming.

  17. Leonardo da Vinci and the origin of semen

    PubMed Central

    Noble, Denis; DiFrancesco, Dario; Zancani, Diego

    2014-01-01

    It is well known that Leonardo da Vinci made several drawings of the human male anatomy. The early drawings (before 1500) were incorrect in identifying the origin of semen, where he followed accepted teaching of his time. It is widely thought that he did not correct this mistake, a view that is reflected in several biographies. In fact, he made a later drawing (after 1500) in which the description of the anatomy is remarkably accurate and must have been based on careful dissection. In addition to highlighting this fact, acknowledged previously in only one other source, this article reviews the background to Leonardo's knowledge of the relevant anatomy. PMID:27494016

  18. Visual tracking of da Vinci instruments for laparoscopic surgery

    NASA Astrophysics Data System (ADS)

    Speidel, S.; Kuhn, E.; Bodenstedt, S.; Röhl, S.; Kenngott, H.; Müller-Stich, B.; Dillmann, R.

    2014-03-01

    Intraoperative tracking of laparoscopic instruments is a prerequisite to realize further assistance functions. Since endoscopic images are always available, this sensor input can be used to localize the instruments without special devices or robot kinematics. In this paper, we present an image-based markerless 3D tracking of different da Vinci instruments in near real-time without an explicit model. The method is based on different visual cues to segment the instrument tip, calculates a tip point and uses a multiple object particle filter for tracking. The accuracy and robustness is evaluated with in vivo data.

  19. Effects of DA-Phen, a dopamine-aminoacidic conjugate, on alcohol intake and forced abstinence.

    PubMed

    Sutera, Flavia Maria; De Caro, Viviana; Cannizzaro, Carla; Giannola, Libero Italo; Lavanco, Gianluca; Plescia, Fulvio

    2016-09-01

    The mesolimbic dopamine (DA) system plays a key role in drug reinforcement and is involved in the development of alcohol addiction. Manipulation of the DAergic system represents a promising strategy to control drug-seeking behavior. Previous studies on 2-amino-N-[2-(3,4-dihydroxy-phenyl)-ethyl]-3-phenyl-propionamide (DA-Phen) showed in vivo effects as a DA-ergic modulator. This study was aimed at investigate DA-Phen effects on operant behavior for alcohol seeking behavior, during reinstatement following subsequent periods of alcohol deprivation. For this purpose, male Wistar rats were tested in an operant paradigm of self-administration; behavioral reactivity and anxiety like-behavior during acute abstinence were evaluated. A characterization of DA-Phen CNS targeting by its quantification in the brain was also carried out. Our findings showed that DA-Phen administration was able to reduce relapse in alcohol drinking by 50% and reversed the alterations in behavioral reactivity and emotionality observed during acute abstinence. In conclusion, DA-Phen can reduce reinstatement of alcohol drinking in an operant-drinking paradigm following deprivation periods and reverse abstinence-induced behavioral phenotype. DA-Phen activity seems to be mediated by the modulation of the DAergic transmission. However further studies are needed to characterize DA-Phen pharmacodynamic and pharmacokinetic properties, and its potential therapeutic profile in alcohol addiction. PMID:27155501

  20. Evolution of the ATLAS PanDA workload management system for exascale computational science

    NASA Astrophysics Data System (ADS)

    Maeno, T.; De, K.; Klimentov, A.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Schovancova, J.; Vaniachine, A.; Wenaus, T.; Yu, D.; Atlas Collaboration

    2014-06-01

    An important foundation underlying the impressive success of data processing and analysis in the ATLAS experiment [1] at the LHC [2] is the Production and Distributed Analysis (PanDA) workload management system [3]. PanDA was designed specifically for ATLAS and proved to be highly successful in meeting all the distributed computing needs of the experiment. However, the core design of PanDA is not experiment specific. The PanDA workload management system is capable of meeting the needs of other data intensive scientific applications. Alpha-Magnetic Spectrometer [4], an astro-particle experiment on the International Space Station, and the Compact Muon Solenoid [5], an LHC experiment, have successfully evaluated PanDA and are pursuing its adoption. In this paper, a description of the new program of work to develop a generic version of PanDA will be given, as well as the progress in extending PanDA's capabilities to support supercomputers and clouds and to leverage intelligent networking. PanDA has demonstrated at a very large scale the value of automated dynamic brokering of diverse workloads across distributed computing resources. The next generation of PanDA will allow other data-intensive sciences and a wider exascale community employing a variety of computing platforms to benefit from ATLAS' experience and proven tools.

  1. [Textual Research on Chiding Disease and Matixiang Herb in Da he wai ke (External Medicine of Da He)].

    PubMed

    Pu, Xiao-Lan; Zhang, Yi; Yang, Wen-Yu; Wu, Ya-Mei

    2012-11-01

    Recorded in Da he wai ke (The External Medicine of Da He) in the Ming dynasty without a corresponding disease title in contemporary scholarly concepts of Traditional Chinese Medicine (TCM), Chiding disease was described as an acute symptomatic disease with inevitable serious conditions of convulsion-like or mania-like behavior, and as a refractory ailment. It was also considered as an alias of Hongsiding (namely the acute lymphangitis) in few ancient books. Matixiang, a Chinese herb for treatment of Chiding, was regarded as a nonsuch drug by Da he wai ke, and was considered as a take-then-cure drug by Chuang yang jing yan quan shu (Compendium for Experience in Sores Diseases). The present studies about Chiding and Matixiang show that: (1) the name of Chiding was first seen in Zhong zang jing (Master Hua's Classic of the Viscera) ; (2) Chiding was rarely mentioned in medical literature of the Song, Yuan and Qing Dynasty, but mostly seen in the Ming Dynasty; (3) Xinding and Huoyanding were found as synonyms of Chiding ; (4) the distinction between Chiding and Hongsiding (flaming sore) was revealed by comparison analysis of their etiology, affected part(s), symptoms, prognosis and syndromic pictures; (5) Chiding on the tongue is the same as "Tongue Ding" or "Sublingual Ding" in contemporary TCM and as "Sublingual Space Infection" in Western Medicine. Moreover, Chiding on the hands, feet or other skin parts could be classified as "Hands/Feet Ding" in contemporary TCM and as "Furuncle" (i.e., Acute Suppurative Folliculitis and Perifolliculitis or cellulites of the tongue) in Western Medicine; (6) Matixiang is probably deduced as Asarum forbesii Maxim., A. ichangense C. Y. Cheng et C. S. Yang, family Aristolochiaceae, or Valeriana jatamansi Jones., family Valerianaceae. PMID:23363849

  2. Chandra Confirmation of a Pulsar Wind Nebula in DA 495

    NASA Technical Reports Server (NTRS)

    Arzoumanian, Z.; Safi-Harb, S.; Landecker, T.L.; Kothes, R.; Camilo, F.

    2008-01-01

    As part of a multiwavelength study of the unusual radio supernova remnant DA 495, we present observations made with the Chandra X-ray Observatory. Imaging and spectroscopic analysis confirms the previously detected X-ray source at the heart of the annular radio nebula, establishing the radiative properties of two key emission components: a soft unresolved source with a blackbody temperature of 1 MK consistent with a neutron star, surrounded by a nontherma1 nebula 40" in diameter exhibiting a power-law spectrum with photon index Gamma = 1.63, typical of a pulsar wind nebula. Morphologically, the nebula appears to be slightly extended along a direction, in projection on the sky, previously demonstrated to be of significance in radio and ASCA observations; we argue that this represents the orientation of the pulsar spin axis. At smaller scales, a narrow X-ray feature is seen extending out 5" from the point source, but energetic arguments suggest that it is not the resolved termination shock of the pulsar wind against the ambient medium. Finally, we argue based on synchrotron lifetimes in the nebular magnetic field that DA 495 represents the first example of a pulsar wind nebula in which electromagnetic flux makes up a significant part, together with particle flux, of the neutron star's wind.

  3. The DA+dMe Binary WD 0334-6400

    NASA Astrophysics Data System (ADS)

    Barrett, P. E.; Schlegel, E. M.; Dupuis, J.; Heathcote, B.

    2005-12-01

    Multiwavelength observations of the star WD 0334-6400 (or Ret 1 in A Catalog and Altas of Cataclysmic Variables: Living Edition) show it to be a DA+dMe binary. Our analysis of the far-ultraviolet continuum and spectral lines reveal that Teff = 36500 K; log g = 7.7; and the photosphere contains C, N, O, Si, P, and S. C/H = 2 x 10-6, which is the highest abundance seen in a DA white dwarf at this temperature. The dMe star is seen as a flux excess in near-infrared photometry and appears to show occasional flaring of about one magnitude as seen in the Harvard plates. There is no evidence of periodic variability in the spectroscopic or photometric data. This paper is based on observations made with the NASA-CNES-CSA FUSE. This research is partially supported by NASA FUSE grants NAG5-12413 and NNG04GL18G.

  4. The 37kDa/67kDa Laminin Receptor acts as a receptor for Aβ42 internalization

    PubMed Central

    Da Costa Dias, Bianca; Jovanovic, Katarina; Gonsalves, Danielle; Moodley, Kiashanee; Reusch, Uwe; Knackmuss, Stefan; Weinberg, Marc S.; Little, Melvyn; Weiss, Stefan F. T.

    2014-01-01

    Neuronal loss is a major neuropathological hallmark of Alzheimer's disease (AD). The associations between soluble Aβ oligomers and cellular components cause this neurotoxicity. The 37 kDa/67 kDa laminin receptor (LRP/LR) has recently been implicated in Aβ pathogenesis. In this study the mechanism underlying the pathological role of LRP/LR was elucidated. Försters Resonance Energy Transfer (FRET) revealed that LRP/LR and Aβ form a biologically relevant interaction. The ability of LRP/LR to form stable associations with endogenously shed Aβ was confirmed by pull down assays and Aβ-ELISAs. Antibody blockade of this association significantly lowered Aβ42 induced apoptosis. Furthermore, antibody blockade and shRNA mediated downregulation of LRP/LR significantly hampered Aβ42 internalization. These results suggest that LRP/LR is a receptor for Aβ42 internalization, mediating its endocytosis and contributing to the cytotoxicity of the neuropeptide by facilitating intra-cellular Aβ42 accumulation. These findings recommend anti-LRP/LR specific antibodies and shRNAs as potential therapeutic tools for AD treatment. PMID:24990253

  5. 32 CFR Appendix F to Part 623 - Power of Attorney (DA Form 4881-4-R)

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 3 2011-07-01 2009-07-01 true Power of Attorney (DA Form 4881-4-R) F Appendix F to Part 623 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY SUPPLIES AND EQUIPMENT LOAN OF ARMY MATERIEL Pt. 623, App. F Appendix F to Part 623—Power of Attorney (DA Form...

  6. A Value-Engaged Approach for Evaluating the Bunche-Da Vinci Learning Academy

    ERIC Educational Resources Information Center

    Greene, Jennifer C.

    2005-01-01

    In 2001, the Bunche Academy was chosen by its district to join in partnership with the Da Vinci Learning Corporation to embark on an ambitious whole-school reform initiative, especially designed by the corporation for low-performing schools. In this chapter, the author describes how, as illustrated in the Bunche-Da Vinci Learning Academy context,…

  7. Processing and Visualizing Planetary Data Using DaVinci: Updates for Portability and Scriptable Execution

    NASA Astrophysics Data System (ADS)

    Edwards, C. S.; Anwar, S.; Hagee, W.; Doerres, D.; Dickensheid, S.; Christensen, P. R.

    2015-06-01

    We present updates to the DaVinci software toolkit that enable stand-alone reading of ISIS3 files, a link between DaVinci and JMARS, the ingestion and use of geospatial information, and a series of executable THEMIS processing scripts.

  8. The Indicative and Subjunctive "da"-complements in Serbian A Syntactic-Semantic Approach

    ERIC Educational Resources Information Center

    Todorovic, Natasa

    2012-01-01

    A syntactic-semantic investigation of subjunctive and indicative "da"-complements in Serbian is conducted in this project. After a careful comparison of Serbian sentence constructions with "da"-complements to the equivalent sentence structures in languages of the Balkans as well as other Slavic languages, it is clearly…

  9. Paśu Ayurvĕda (veterinary medicine) in Garudapurăņa.

    PubMed

    Varanasi, Subhose; Narayana, A

    2007-01-01

    The history of veterinary medicine is closely tied to the development of human medicine. Evidence of animal medicine has been found in ancient civilizations, such as those of the Hindu, Babylonians, Hebrews, Arabs, Greeks, and Romans. Ancient Indian literature in the form of the holy Vĕda, Purăna, Brăhmaņa, epics, etc. is flooded with information on animal care. The Purăņa are ancient scriptures discuss varied topics like devotion to God and his various aspects, traditional sciences like Ayurvĕda, Jyŏtişa (Astrology), cosmology, concepts like dharma, karma, reincarnation and many others. The treatment of animal diseases using Ayurvedic medicine has been mentioned in Garudapurăna, Agnipurăņa, Atri-samhită, Matsyapurăņa and many other texts. The Garudapurăņa is one of the important Săttvika purăna, the subject matter is divided into two parts, viz. Pŭrvakhaņda (first part) and an Uttarakhaņda (subsequent part). Gavăyurvĕda, Gajăyurvĕda narrated briefly and Aśvăyurvĕda described detailly in Pŭrvakhaņda. PMID:19580108

  10. 32 CFR Appendix F to Part 623 - Power of Attorney (DA Form 4881-4-R)

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Power of Attorney (DA Form 4881-4-R) F Appendix F to Part 623 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY SUPPLIES AND EQUIPMENT LOAN OF ARMY MATERIEL Pt. 623, App. F Appendix F to Part 623—Power of Attorney (DA Form...

  11. Topological studies of spinach 22 kDa protein of Photosystem II.

    PubMed

    Kim, S; Pichersky, E; Yocum, C F

    1994-12-30

    An intrinsic 22 kDa polypeptide is associated with the O2-evolving Photosystem II core complex in a variety of green plants, although it does not appear to be required for O2 evolution. Digestion of thylakoid membranes and isolated Photosystem II preparations with trypsin, followed by immunoblotting using spinach anti-22 kDa antibodies, leads to two observations: (1) the domain between the 2nd and 3rd transmembrane helices of the 22 kDa protein is stromally exposed, and (2) only in a reaction center complex preparation, lacking the chlorophyll a/b-light harvesting complex II, is there extensive proteolytic cleavage of the 22 kDa protein. We also found that after, but not prior to, selective extraction of the 22 and 10 kDa proteins from Photosystem II membranes, the chlorophyll a/b-light harvesting complex II can be separated from the Photosystem II reaction center core by precipitation with MgCl2. This result suggests that the 22 kDa polypeptide is located between the Photosystem II reaction center polypeptides and light-harvesting complex II; it is possible that the protein serves as a link between the two protein complexes. The presence of the 22 kDa protein in several species was also examined by immunoblotting with polyclonal spinach anti-22 kDa antibodies. PMID:7803450

  12. 32 CFR Appendix E to Part 623 - Surety Bond (DA Form 4881-3-R)

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Surety Bond (DA Form 4881-3-R) E Appendix E to Part 623 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY SUPPLIES AND EQUIPMENT LOAN OF ARMY MATERIEL Pt. 623, App. E Appendix E to Part 623—Surety Bond (DA Form...

  13. A Creative Approach to the Common Core Standards: The Da Vinci Curriculum

    ERIC Educational Resources Information Center

    Chaucer, Harry

    2012-01-01

    "A Creative Approach to the Common Core Standards: The Da Vinci Curriculum" challenges educators to design programs that boldly embrace the Common Core State Standards by imaginatively drawing from the genius of great men and women such as Leonardo da Vinci. A central figure in the High Renaissance, Leonardo made extraordinary contributions as a…

  14. Pharmacological action of DA-9701 on the motility of feline stomach circular smooth muscle.

    PubMed

    Nguyen, Thanh Thao; Song, Hyun Ju; Ko, Sung Kwon; Sohn, Uy Dong

    2015-03-01

    DA-9701, a new prokinetic agent for the treatment of functional dyspepsia, is formulated with Pharbitis semen and Corydalis tuber. This study wasconducted to determine the pharmacological action of DA-9701 and to identify the receptors involved in DA-9701 -induced contractile responsesin the feline gastric corporal, fundic and antral circular smooth muscle. Concentration-response curve to DA-9701 was established. The tissue trips were exposed to methylsergide, ketanserin, ondansetron, GR 113808, atropine and dopamine before administration of DA-9701. The contractile force was determined before and after administration of drugs by a polygraph.DA-9701 enhanced the spontaneous contractile amplitude of antrum, corpus and fundus. However, it did not change the spontaneous contractile frequency of antrum and corpus, but concentration-dependently reduced that of fundus. In the fundus, DA-9701 -induced tonic contractions were inhibited by dopamine, methylsergide, ketanserine, ondansetron or GR 113808 respectively, but not by atropine, indicating that the contractile responses are mediated by multiple receptors: 5-HT2, 5-HT3, 5-HT4, and dopamine receptors. In the corpus, DA-9701-induced contractions were blocked by atropine, dopamine or GR 113808, but not by methysergide, ketanserin or ondansetron, indicating that they are involved in receptors on both, smooth muscles and neurons: 5-HT4 and dopamine receptors. However, contractile responses to DA-9701 are mainly mediated by dopamine receptors in the antrum. These results suggest that DA-9701 has important roles in gastric accommodation by enhancing tonic activity of fundus, and in gastric emptying and gastrointestinal transit by phasic contractions of corpus and antrum mediated by multiple receptors. PMID:25980179

  15. The Effect of DA-9701 in Opioid-induced Bowel Dysfunction of Guinea Pig

    PubMed Central

    Hussain, Zahid; Rhee, Kwang Won; Lee, Young Ju; Park, Hyojin

    2016-01-01

    Background/Aims Opioid induced bowel dysfunction (OIBD) is associated with decreased gastrointestinal (GI) propulsive activity due to intake of opioid analgesics. DA-9701, a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber has promising effects on GI motor function. Therefore, we aim to evaluate the prokinetic effects of DA-9701 in an OIBD model of guinea pig. Methods The ileal and distal colon muscle contraction in presence of different doses of DA-9701, morphine, and combination (morphine + DA-9701) was measured by tissue bath study. The prokinetic effect of DA-9701 was assessed by charcoal transit and fecal pellet output assay in an OIBD model of guinea pig. Results DA-9701 significantly increased the amplitude and area under the curve of ileal muscle contraction, while there was insignificant effect on the distal colon compared to the control. The maximal amplitude of ileal muscle contraction was acquired at a concentration of 10 μg/mL of DA-9701. In contrast, morphine significantly decreased the amplitude of ileal and distal colon muscle contraction compared to the control. Morphine delayed both upper (P < 0.01) and lower (P < 0.05) GI transit, and delayed GI transit was restored by the administration of DA-9701. Morphine induced reduction of contractility was significantly ameliorated by addition of DA-9701 in both ileal and distal colon muscles. Conclusions DA-9701 significantly increased the amplitude of contraction of the ileal muscle, however the distal colon muscle contraction was insignificant. Additionally, it restored delayed upper and lower GI transit in an OIBD model of guinea pig, and it might prove to be a useful candidate drug in a clinical trial for OIBD. PMID:26932898

  16. [Regarding the Manuscript D " Dell' occhio " of Leonardo da Vinci].

    PubMed

    Heitz, Robert F

    2009-01-01

    Leonardo da Vinci's Manuscript D consists of five double pages sheets, which, folded in two, comprise ten folios. This document, in the old Tuscan dialect and mirror writing, reveals the ideas of Leonardo on the anatomy of the eye in relation to the formation of images and visual perception. Leonardo explains in particular the behavior of the rays in the eye in terms of refraction and reflection, and is very mechanistic in his conception of the eye and of the visual process. The most significant innovations found in these folios are the concept of the eye as a camera obscura and the intersection of light rays in the interior of the eye. His texts nevertheless show hesitation, doubts and a troubled confusion, reflecting the ideas and uncertainties of his era. He did not share his results in his lifetime, despite both printing and etching being readily available to him. PMID:19852385

  17. A 92-kDa human immunostimulatory protein.

    PubMed Central

    Fontan, E; Briend, E; Saklani-Jusforgues, H; d'Alayer, J; Vandekerckhove, J; Fauve, R M

    1994-01-01

    We purified to apparent homogeneity a human urinary glycoprotein of 92 kDa (HGP.92) that, administered intravenously at 250 micrograms/kg, fully protected mice against a lethal inoculum of Listeria monocytogenes. Since HGP.92 protected scid mice, which lack B and T lymphocytes, this increased resistance to Listeria did not appear to be lymphocyte mediated. Furthermore, inflammatory macrophages incubated with 6 nM HGP.92 inhibited the growth of Lewis carcinoma cells in vitro. These two activities appeared to depend on an oligosaccharide moiety, as they were lost after N-Glycanase treatment of HGP.92. Thus, the biological activity of HGP.92 was in some way related to a glycan moiety. Images PMID:8078887

  18. DBS -- An rlogin multiplexer and output logger for DA systems

    SciTech Connect

    Oleynik, G.; Appleton, L.; Udumula, L.; Votava, M.

    1994-04-01

    DART Bootstrap Services (dbs) is the first component of run-control for the DART Data Acquisition system -- the DA for the 96` round of experiments at Fermilab -- though it has potential usefulness as a powerful tool in other distributed applications. dbs is an rlogin session multiplexer. It allows a user, running a single program, to start up any number of remote login sessions, feed shell commands to them, and collect their output into a single (or multiple) log files (a server keeps the sessions open and collects their output). From this program, any session can be attached to interactively so it appears just like an rlogin session -- dbs becomes transparent. When finished with this interactive mode, the user can escape back to dbs and attach to a different session if so desired. Among many other useful features, dbs supplies a mechanism for cleanup (deletion) of all processes created under a session, allowing a fresh start.

  19. VLBI Radar of the 2012 DA14 Asteroid

    NASA Astrophysics Data System (ADS)

    Nechaeva, M. B.; Dugin, N. A.; Antipenko, A. A.; Bezrukov, D. A.; Bezrukov, V. V.; Voytyuk, V. V.; Dement'ev, A. F.; Jekabsons, N.; Klapers, M.; Konovalenko, A. A.; Kulishenko, V. F.; Nabatov, A. S.; Nesteruk, V. N.; Putillo, D.; Reznichenko, A. M.; Salerno, E.; Snegirev, S. D.; Tikhomirov, Yu. V.; Khutornoy, R. V.; Skirmante, K.; Shmeld, I.; Chagunin, A. K.

    2015-03-01

    An experiment on VLBI radar of the 2012 DA14 asteroid was carried out on February 15-16, 2011 at the time of its closest approach to the Earth. The research teams of Kharkov (Institute of Radio Astronomy of the National Academy of Sciences of Ukraine), Evpatoria (National Space Facilities Control and Test Center), Nizhny Novgorod (Radiophysical Research Institute), Bologna (Istituto di Radioastronomia (INAF)), and Ventspils (Ventspils International Radioastronomy Center) took part in the experiment. The asteroid was irradiated by the RT-70 planetary radar (Evpatoria) at a frequency of 5 GHz. The reflected signal was received using two 32-m radio telescopes in Medicina (Italy) and Irbene (Latvia) in radiointerferometric mode. The Doppler frequency shifts in bi-static radar mode and interference frequency in VLBI mode were measured. Accuracy of the VLBI radar method for determining the radial and angular velocities of the asteroid were estimated.

  20. 70 DA WHITE DWARFS IDENTIFIED IN LAMOST PILOT SURVEY

    SciTech Connect

    Zhao, J. K.; Luo, A. L.; Zhao, G.; Oswalt, T. D. E-mail: gzhao@bao.ac.cn E-mail: toswalt@fit.edu

    2013-06-01

    We present a spectroscopically identified catalog of 70 DA white dwarfs (WDs) from the LAMOST pilot survey. Thirty-five are found to be new identifications after cross-correlation with the Eisenstein et al. and Villanova catalogs. The effective temperature and gravity of these WDs are estimated by Balmer lines fitting. Most of them are hot WDs. The cooling times and masses of these WDs are estimated by interpolation in theoretical evolution tracks. The peak of the mass distribution is found to be {approx}0.6 M {sub Sun }, which is consistent with prior work in the literature. The distances of these WDs are estimated using the method of synthetic spectral distances. All of these WDs are found to be in the Galactic disk from our analysis of space motions. Our sample supports the expectation that WDs with high mass are concentrated near the plane of the Galactic disk.

  1. DBS - an rlogin multiplexor and output logger for DA systems

    SciTech Connect

    Oleynik, G.; Appleton, L.; Udumula, L.; Votava, M.

    1994-12-31

    DART Bootstrap Services (dbs) is the first component of run-control for the DART Data Acquisition system - the DA for the 96{prime} round of experiments at Fermilab - though it has potential usefulness as a powerful tool in other distributed applications, dbs is an rlogin session multiplexer. It allows a user, running a single program, to start up any number of remote login sessions, feed shell commands to them, and collect their output into a single (or multiple) logfiles (a server keeps the sessions open and collects their output). From this program, any session can be attached to interactively so it appears just like an rlogin session - dbs becomes transparent. When finished with this interactive mode, the user can escape back to dbs and attach to a different session if so desired. Among many other useful features, dbs supplies a mechanism for cleanup (deletion) of all processes created under a session, allowing a fresh start.

  2. 40 CFR 60.45Da - Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... nitrogen oxides (NOX) and carbon monoxide (CO). 60.45Da Section 60.45Da Protection of Environment... SOURCES Standards of Performance for Electric Utility Steam Generating Units § 60.45Da Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO). (a) The owner or operator of...

  3. 40 CFR 60.45Da - Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... nitrogen oxides (NOX) and carbon monoxide (CO). 60.45Da Section 60.45Da Protection of Environment... SOURCES Standards of Performance for Electric Utility Steam Generating Units § 60.45Da Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO). (a) The owner or operator of...

  4. 40 CFR 60.45Da - Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... nitrogen oxides (NOX) and carbon monoxide (CO). 60.45Da Section 60.45Da Protection of Environment... SOURCES Standards of Performance for Electric Utility Steam Generating Units § 60.45Da Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO). (a) The owner or operator of...

  5. Production of aromatic hydrocarbons through catalytic pyrolysis of γ-valerolactone from biomass.

    PubMed

    Zhao, Yan; Fu, Yao; Guo, Qing-Xiang

    2012-06-01

    In the present study, γ-valerolactone (GVL) is firstly reported to be converted into aromatic hydrocarbons through catalytic pyrolysis. The catalysts and reaction conditions are both critical in maximizing the hydrocarbon selectivity. Four zeolites, i.e. MCM-41, β-zeolite, ZSM-5 and HZSM-5 were tested in this work, among which HZSM-5 (Si/Al=25) was found to be the most effective catalyst in both reactivity and selectivity. Under the reaction temperature of 500 °C, the highest carbon yield of 56.71% of aromatics was achieved from GVL with HZSM-5 (Si/Al=25) as catalyst. Moreover, the HZSM-5 catalyst was recycled for five times without significant decrease in product selectivity. PMID:22507905

  6. Antimicrobial Properties of an Immunomodulator - 15 kDa Human Granulysin

    PubMed Central

    Wei, Hung-Mu; Lin, Li-Chih; Wang, Chiu-Feng; Lee, Yi-Jang; Chen, Yuan-Tsong; Liao, You-Di

    2016-01-01

    Granulysin, a cationic protein expressed by human natural killer cells and cytotoxic T lymphocytes, is a mediator for drug-induced Stevens-Johnson syndrome and graft-versus-host disease. Some 15 kDa granulysin are processed into 9 kDa forms and sequestered in cytolytic granules, while others are constitutively secreted into body fluids. Both 9 and 15 kDa granulysin have been shown to be a serum marker for cell-mediated immunity. Furthermore, 15 kDa is able to activate monocyte differentiation. However, its antimicrobial properties have not been clearly addressed. Here, we report a novel method to prepare both the soluble 9 and 15 kDa granulysin and show that the 15 kDa form is more effective than the 9 kDa form in exerting specific antimicrobial activity against Pseudomonas aeruginosa within a range of few micromolars. We also show that the 15 kDa granulysin is able to hyperpolarize the membrane potential and increase membrane permeability of treated bacteria. Interestingly, the bactericidal activity and membrane permeability of the granulysins were markedly reduced at lower pH (pH 5.4) as a result of probable increase in hydrophobicity of the granulysins. Additionally, we’ve also shown the granulysin to inhibit biofilm formation by P. aeruginosa. These results suggest that the 15 kDa granulysin exhibits a novel mechanism in bacteria killing in a way that’s different from most antimicrobial peptides. Our novel granulysin preparation methodology will be useful for further study of action mechanisms of other antimicrobial, cytotoxic and immunomodulating properties in granulysin-mediated diseases. PMID:27276051

  7. Neospora caninum: identification of 19-, 38-, and 40-kDa surface antigens and a 33-kDa dense granule antigen using monoclonal antibodies.

    PubMed

    Schares, G; Dubremetz, J F; Dubey, J P; Bärwald, A; Loyens, A; Conraths, F J

    1999-06-01

    Neospora caninum, a coccidian parasite closely related to Toxoplasma gondii, can infect a broad host range and is regarded as an important cause of bovine abortion worldwide. In the present study, four antigens of N. caninum were partially characterized using monoclonal antibodies. Immunofluorescence of viable tachyzoites as well as the immunoprecipitation of antigens extracted from tachyzoites previously labeled by surface biotinylation revealed that three of these antigens with apparent molecular weights of 40, 38, and 19 kDa are located in the outer surface membrane of this parasite stage. Further evidence for the surface localization of the 38-kDa antigen was obtained by immunoelectron microscopy. In addition to the surface molecules, an antigen located in dense granules and in the tubular network of the parasitophorous vacuole was detected by another monoclonal antibody. When tachyzoite antigens separated under nonreducing conditions were probed on Western blots, this antibody reacted mainly with a 33-kDa antigen. Immunohistochemical analysis of infected tissue sections indicated that the 33-kDa dense granule antigen is present in both tachyzoites and bradyzoites, while the 38-kDa surface antigen from tachyzoites seems to be absent in bradyzoites. PMID:10366536

  8. Respostas religiosas à aids no Brasil: impressões de pesquisa acerca da Pastoral de DST/Aids da Igreja Católica1

    PubMed Central

    Seffner, Fernando; Silva, Cristiane Gonçalves Meireles da; Maksud, Ívia; Garcia, Jonathan; Rios, Luís Felipe; Natividade, Marcelo; Borges, Priscila Rodrigues; Parker, Richard; Terto, Veriano

    2009-01-01

    O texto encontra-se estruturado em quatro partes. Na primeira delas, apresentamos um conjunto de considerações e informações acerca da situação da aids no Brasil, das relações entre religião, sexualidade, aids e estado laico, bem como uma descrição mais clara do Projeto Respostas Religiosas ao HIV/Aids no Brasil, do qual este texto apresenta algumas impressões de pesquisa preliminares. A seguir, dedicamos um item a apresentação da Pastoral de DST/Aids, sua história, estrutura e objetivos. No item seguinte problematizamos diversas questões em particular no âmbito das relações Estado e Igreja, relações entre agentes de pastoral e hierarquia da Igreja, e questões ligadas mais diretamente à sexualidade e aids, todas referenciadas ao trabalho da Pastoral de DST/Aids. Ao final, apresentamos a bibliografia e fontes consultadas. PMID:20442806

  9. PD2P: PanDA Dynamic Data Placement for ATLAS

    NASA Astrophysics Data System (ADS)

    Maeno, T.; De, K.; Panitkin, S.

    2012-12-01

    The PanDA (Production and Distributed Analysis) system plays a key role in the ATLAS distributed computing infrastructure. PanDA is the ATLAS workload management system for processing all Monte-Carlo (MC) simulation and data reprocessing jobs in addition to user and group analysis jobs. The PanDA Dynamic Data Placement (PD2P) system has been developed to cope with difficulties of data placement for ATLAS. We will describe the design of the new system, its performance during the past year of data taking, dramatic improvements it has brought about in the efficient use of storage and processing resources, and plans for the future.

  10. Stability of new carbapenem DA-1131 to renal dipeptidase (dehydropeptidase I).

    PubMed

    Park, Sung Wook; We, Jeoung Soon; Kim, Gye Won; Choi, Seong Hak; Park, Haeng Soon

    2002-02-01

    The stability of DA-1131 to renal dipeptidase (RDPase) (EC 3.4.13.19) was compared with that of imipenem and meropenem by V(max)/K(m) ratios as an index of the enzyme's preference for substrates. Our results showed a decreasing order of imipenem (6.24), meropenem (2.41), and DA-1131 (1.39). The biochemical evaluation of DA-1131 as the least preferred substrate of RDPase suggests its potential use as a novel beta-lactam antibiotic which may be usable without coadministration of RDPase inhibitors once its clinical suitability is proven. PMID:11796382

  11. Arbitrary Amplitude DIA and DA Solitary Waves in Adiabatic Dusty Plasmas

    SciTech Connect

    Mamun, A. A.; Jahan, N.; Shukla, P. K.

    2008-10-15

    The dust-ion-acoustic (DIA) as well as the dust-acoustic (DA) solitary waves (SWs) in an adiabatic dusty plasma are investigated by the pseudo-potential approach which is valid for arbitrary amplitude SWs. The role of the adiabaticity of electrons and ions in modifying the basic features (polarity, speed, amplitude and width) of arbitrary amplitude DIA and DA SWs are explicitly examined. It is found that the effects of the adiabaticity of electrons and ions significantly modify the basic features (polarity, speed, amplitude and width) of the DIA and DA SWs. The implications of our results in space and laboratory dusty plasmas are briefly discussed.

  12. 2012 DA14 and Chelyabinsk: Same Day Coincidence?

    NASA Astrophysics Data System (ADS)

    Chapman, Clark R.

    2013-10-01

    A long anticipated near-miss by near-Earth asteroid (NEA) 2012 DA14 on 15 February 2013 was upstaged 16 hours earlier by the impact and atmospheric explosion of a ~20 m NEA over Chelyabinsk, Russia. DA14 was earlier estimated to be 45 m across and passage at a distance under geosynchronous satellites was considered to be a record close approach by an object of that size, a once-in-40-years event. Actual Earth impact by a 20 m NEA had been estimated to be a once-in-200-years event. A simplistic calculation gives a probability of these happening on the same day of 1-in-a-billion. Within hours of the Chelyabinsk impact, it was recognized and widely reported that the two asteroids were in very different orbits and could not, at least in any readily understandable way, be physically related to each other (e.g. fragments of the same precursor body). Also, some early reports suggested that the two asteroids had very different compositions, further undermining the possibility they were pieces of the same body. (It seems unlikely, though certainly conceivable, that the two NEAs could have different compositions yet have some kind of causal connection resulting in the same-day events.) Nevertheless, incredibly tiny probabilities beg for an explanation. Here, with the benefit of hindsight, I re-examine issues that affect the probabilities, such as size, albedo, probable composition, and numbers of NEAs of these sizes. I also consider difficult issues of framing the apparent coincidence, which dominate other uncertainties. Updated information about the physical nature of the two asteroids somewhat modifies the original estimates of probabilities. Moreover, more proper ways of framing elements of the coincidence considerably reduce the improbability of the same-day events, but not nearly to the level (e.g. 1-in-1000 or perhaps 1-in-10,000) where we could rationalize dismissing the events as “just a coincidence.” The events of 15 February 2013 deserve more sophisticated

  13. Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

    SciTech Connect

    Zhao, Na; Li, Siwen; Wang, Jinyi; Zhang, Ronglan; Gao, Ruimin; Zhao, Jianshe; Wang, Junlong

    2015-05-15

    M{sub 2}(PcAN){sub 2} (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M{sub 2}(PcAN){sub 2}–W-HZSM-5) or the M{sub 2}(PcTN){sub 2} doping W-HZSM-5 (M{sub 2}(PcTN){sub 2}/W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu{sub 2}(PcAN){sub 2}–W-HZSM-5 and Cu{sub 2}(PcTN){sub 2}/W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV–Vis and calcination temperature was obtained by TG-DSC for Cu{sub 2}(PcTN){sub 2}/W-HZSM-5. Catalysts were characterized by EA, IR, XRD, SEM, TEM, ICP, and N{sub 2} adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed. - Graphical abstract: The ODS reaction schematic shows the reaction mechanism of ultra-deep desulfurization. The sulfur compounds are oxidized to their corresponding sulfoxides or sulfones through the use of oxygen and catalysts. The reaction process of ultra-deep desulfurization. - Highlights: • A kind of novel catalyst for deep desulfurization was synthesized. • Cu{sub 2}(PcAN){sub 2}–W-HZSM-5 exhibits excellent catalytic performance for desulfurization. • The reaction conditions that affect desulfurization efficiency are investigated. • The reaction process of model sulfur compounds is proposed.

  14. D.A. Henderson: acting globally, thinking locally.

    PubMed

    Henderson, D A

    2003-08-01

    They had said that it couldn't be done-the worldwide eradication of smallpox. To hear D.A. Henderson tell it, the job of leading the World Health Organization's initiative to conquer the disease in the 1960s and 1970s rather fell into his lap. In fact, he describes each of the posts that he has held with great modesty, beginning with his military service at the Centers for Disease Control and Prevention all the way through his assignments as Dean of Public Health at Johns Hopkins, Associate Director of the Office of Science and Technology Policy in the Executive Office of the President, and more recently as Director of the Office of Public Health Preparedness under Secretary Thompson at the Department of Health and Human Services. Confronted with enormous challenges in terms of public health initiatives, Henderson describes each assignment as a matter of communicating with the people he works with and the people that he serves, and drawing on their insights to devise strategies for accomplishing the task at hand. With bioterrorism posing one of the major public health concerns to face the United States and the world, it's gratifying to know that someone with Henderson's track record and wide-ranging expertise is paying attention and making sure that medical and government officials are preparing to respond to the threat. Again and again, Henderson appears to have the knack for showing up in the right place at the right time with just the right idea. PMID:14993437

  15. Robotic Partial Nephrectomy with the Da Vinci Xi

    PubMed Central

    Kallingal, George J. S.; Swain, Sanjaya; Darwiche, Fadi; Punnen, Sanoj; Manoharan, Murugesan; Gonzalgo, Mark L.; Parekh, Dipen J.

    2016-01-01

    Purpose. The surgical expertise to perform robotic partial nephrectomy is heavily dependent on technology. The Da Vinci Xi (XI) is the latest robotic surgical platform with significant advancements compared to its predecessor. We describe our operative technique and experience with the XI system for robotic partial nephrectomy (RPN). Materials and Methods. Patients with clinical T1 renal masses were offered RPN with the XI. We used laser targeting, autopositioning, and a novel “in-line” port placement to perform RPN. Results. 15 patients underwent RPN with the XI. There were no intraoperative complications and no operative conversions. Mean console time was 101.3 minutes (range 44–176 minutes). Mean ischemia time was 17.5 minutes and estimated blood loss was 120 mLs. 12 of 15 patients had renal cell carcinoma. Two patients had oncocytoma and one had benign cystic disease. All patients had negative surgical margins and pathologic T1 disease. Two postoperative complications were encountered, including one patient who developed a pseudoaneurysm and one readmitted for presumed urinary tract infection. Conclusions. RPN with the XI system can be safely performed. Combining our surgical technique with the technological advancements on the XI offers patients acceptable pathologic and perioperative outcomes. PMID:26977144

  16. Audio annotation watermarking with robustness against DA/AD conversion

    NASA Astrophysics Data System (ADS)

    Qian, Kun; Kraetzer, Christian; Biermann, Michael; Dittmann, Jana

    2010-01-01

    In the paper we present a watermarking scheme developed to meet the specific requirements of audio annotation watermarking robust against DA/AD conversion (watermark detection after playback by loudspeaker and recording with a microphone). Additionally the described approach tries to achieve a comparably low detection complexity, so it could be embedded in the near future in low-end devices (e.g. mobile phones or other portable devices). We assume in the field of annotation watermarking that there is no specific motivation for attackers to the developed scheme. The basic idea for the watermark generation and embedding scheme is to combine traditional frequency domain spread spectrum watermarking with psychoacoustic modeling to guarantee transparency and alphabet substitution to improve the robustness. The synchronization and extraction scheme is designed to be much less computational complex than the embedder. The performance of the scheme is evaluated in the aspects of transparency, robustness, complexity and capacity. The tests reveals that 44% out of 375 tested audio files pass the simulation test for robustness, while the most appropriate category shows even 100% robustness. Additionally the introduced prototype shows an averge transparency of -1.69 in SDG, while at the same time having a capacity satisfactory to the chosen application scenario.

  17. Near-UV absorption in very cool DA white dwarfs

    SciTech Connect

    Saumon, D.; Holberg, J. B.; Kowalski, P. M. E-mail: holberg@argus.lpl.arizona.edu

    2014-07-20

    The atmospheres of very cool, hydrogen-rich white dwarfs (WDs) (T{sub eff} < 6000 K) are challenging to model because of the increased complexity of the equation of state, chemical equilibrium, and opacity sources in a low-temperature, weakly ionized dense gas. In particular, many models that assume relatively simple models for the broadening of atomic levels and mostly ideal gas physics overestimate the flux in the blue part of their spectra. A solution to this problem that has met with some success is that additional opacity at short wavelengths comes for the extreme broadening of the Lyman α line of atomic H by collisions primarily with H{sub 2}. For the purpose of validating this model more rigorously, we acquired Hubble Space Telescope STIS spectra of eight very cool WDs (five DA and three DC stars). Combined with their known parallaxes, BVRIJHK, and Spitzer IRAC photometry, we analyze their entire spectral energy distribution (from 0.24 to 9.3 μm) with a large grid of model atmospheres and synthetic spectra. We find that the red wing of the Lyman α line reproduces the rapidly decreasing near-UV flux of these very cool stars very well. We determine better constrained values of T{sub eff} and gravity as well as upper limits to the helium abundance in their atmospheres.

  18. Granite geomorphology and its geological controls, Serra da Estrela, Portugal

    NASA Astrophysics Data System (ADS)

    Migoń, Piotr; Vieira, Gonçalo

    2014-12-01

    Serra da Estrela is an elevated granite massif in central Portugal, characterized by extensive plateau surfaces incised by deep valleys affected by Quaternary glaciation, bounded by steep fault-generated escarpments. The presence of seven major textural variants of granite provides an opportunity to study the relationships between lithology and relief, whereas DEM analysis helped to show the relationships between lithology and topography objectively. The higher ground is associated with fine- to medium-grained granites and is typified by planar surfaces of low gradient, with occasional angular tors and rock pedestals. Block fields built by angular material are common in the parts that were not previously glaciated. Less elevated parts of the plateau are supported by medium- to coarse-grained granites and show more varied topography, with an abundance of tors, boulder piles, and depressions. Lithological boundaries locally coincide with slope breaks but this is not the rule. In the northern part of the massif a deep topographic basin has evolved in biotite granite, whereas deeply incised valleys follow major fault lines. Geological controls show a hierarchy, in that gross relief reflects the pattern of tectonic uplift and subsidence, whereas lithology and then fracture patterns become more and more important if one focuses on smaller and smaller landforms.

  19. DA WHITE DWARFS OBSERVED IN THE LAMOST PILOT SURVEY

    SciTech Connect

    Zhang Yueyang; Deng Licai; Liu Chao; Carrell, Kenneth; Yang Fan; Gao Shuang; Xu Yan; Li Jing; Zhang Haotong; Zhao Yongheng; Luo Ali; Bai Zhongrui; Yuan Hailong; Lepine, Sebastien; Newberg, Heidi Jo; Carlin, Jeffrey L.; Jin Ge

    2013-08-01

    A total of {approx}640, 000 objects from the LAMOST pilot survey have been publicly released. In this work, we present a catalog of DA white dwarfs (DAWDs) from the entire pilot survey. We outline a new algorithm for the selection of white dwarfs (WDs) by fitting Sersic profiles to the Balmer H{beta}, H{gamma}, and H{delta} lines of the spectra, and calculating the equivalent width of the Ca II K line. Two thousand nine hundred sixty-four candidates are selected by constraining the fitting parameters and the equivalent width of the Ca II K line. All the spectra of candidates are visually inspected. We identify 230 DAWDs (59 of which are already included in the Villanova and SDSS WD catalogs), 20 of which are DAWDs with non-degenerate companions. In addition, 128 candidates are classified as DAWDs/subdwarfs, which means the classifications are ambiguous. The result is consistent with the expected DAWD number estimated based on the LEGUE target selection algorithm.

  20. Adenovirus type 2 encoded early 11 kDa protein

    SciTech Connect

    Murthy, S.V.K.N.; Kapoor, Q.S.

    1986-05-01

    Several adenovirus type 2 (Ad2) encoded early proteins have been identified in viral infected human KB cells. These proteins are of great interest as they play key roles in cell transformation, viral DNA synthesis and gene expression. They have partially purified an AD2 encoded early polypeptide of an apparent molecular weight of 11 kilodaltons from the nuclei of viral infected cells labelled with /sup 35/S-methionine. After DNA removal from the nuclear extracts, the polypeptide was isolated using DEAE-Sephacel anion exchange and Biogel P-10 gel filtration columns. This simple two step procedure yielded several fold purification of the polypeptide. Antisera raised in mice against an Ad2 transformed rat cell line 8617 was found to immunoprecipitate the 11 kDa polypeptide from the nuclear extract of Ad2 infected KB cells. After relating this protein to an open reading frame of an Ad2 early gene block by matching the amino acid sequences to the nucleotide sequences of early genes, they plan to functionally characterize this protein by using monoclonal antibodies in in vivo and in vitro experiments.

  1. Biogeochemical Indicators of Paleoenvironmental Changes in a Humid Region of Amazonia (Lagoa da Pata, Sao Gabriel da Cachoeira)

    NASA Astrophysics Data System (ADS)

    Cordeiro, R. C.; Turcq, B.; Mendes, L. G.; Azeredo, J. B.; Moura, M. S.; de Oliveira, A. R.; Monteiro, F.; Santelli, R. E.

    2004-12-01

    Analysis of four sediment core collected in Lagoa da Pata lake show significant changes in the environmental history of Amazonia during the last 40,000 years. The Lagoa da Pata Lake (0°17'S, 66°40'W) is located on the top of the Morro dos Seis Lagos, an isolated hill in the extensive forested plane surface of high Rio Negro basin. The climate in the region presents mean annual precipitation around 3000 mm without dry season. Three distinct sections are clearly identified in the LPT III, LPT IV and LPT V cores. They consist of upper and lower organic-rich layers, separated by a clastic layer which represents a short period of rapid accumulation around 18 ka BP. Analysis of the organic matter composition by d13C and d15N, total Carbon and Nitrogen, sedimentary chlorophyll concentration and organic matter petrography show three different phases related to organic matter deposition. Between, at least 46,000 and 31,000 14C yr B.P., the lake presented a high water level attested by high accumulation rates of organic carbon. Values of d13C (around -32%) associated to high C/N ratio demonstrate a lignocellulosic material contribution in this phase; the second phase between the 31000 yr 14C B.P. and 18000 14C B.P. is characterised by a lower productivity attested by low sedimentary chlorophyll and total organic carbon values. The d13C values increase with medium values around -28% that may correspond to an input of organic matter rich in C4 plants (grasses). The sedimentation rate decreases significantly. High charcoal fluxes were observed in this period. At around 18000 14C yr BP, there appears to have been a sudden input of clastic material. This is represented by a sandy facies, which exhibits lower carbon contents. From 18000 14C yr B.P. to the present time occurred an increase in lacustrine productivity marked by an increase in carbon and chlorophyll derivate accumulation rates. The C/N values dropped indicting an algae organic matter contribution. It probably

  2. Temperature and Gravity Dependence of Trace Element Abundances in Hot DA White Dwarfs (94-EUVE-094)

    NASA Technical Reports Server (NTRS)

    Finley, David S.

    1998-01-01

    EUV spectroscopy has shown that DA white dwarfs hotter than about 45,000 K may contain trace heavy elements, while those hotter than about 50,000 K almost always have significant abundances of trace heavy elements. One of our continuing challenges is to identify and determine the abundances of these trace constituents, and then to relate the observed abundance patterns to the present conditions and previous evolutionary histories of the hot DA white dwarfs.

  3. Role of Brønsted acid in selective production of furfural in biomass pyrolysis.

    PubMed

    Zhang, Haiyan; Liu, Xuejun; Lu, Meizhen; Hu, Xinyue; Lu, Leigang; Tian, Xiaoning; Ji, Jianbing

    2014-10-01

    In this work, the role of Brønsted acid for furfural production in biomass pyrolysis on supported sulfates catalysts was investigated. The introduction of Brønsted acid was shown to improve the degradation of polysaccharides to intermediates for furfural, which did not work well when only Lewis acids were used in the process. Experimental results showed that CuSO4/HZSM-5 catalyst exhibited the best performance for furfural (28% yield), which was much higher than individual HZSM-5 (5%) and CuSO4 (6%). The optimum reaction conditions called for the mass ratio of CuSO4/HZSM-5 to be 0.4 and the catalyst/biomass mass ratio to be 0.5. The recycled catalyst exhibited low productivity (9%). Analysis of the catalysts by Py-IR revealed that the CuSO4/HZSM-5 owned a stronger Brønsted acid intensity than HZSM-5 or the recycled CuSO4/HZSM-5. Therefore, the existence of Brønsted acid is necessary to achieve a more productive degradation of biomass for furfural. PMID:25106779

  4. Optimizing anti-coking abilities of zeolites by ethylene diamine tetraacetie acid modification on catalytic fast pyrolysis of corn stalk

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Zhong, Zhaoping; Song, Zuwei; Ding, Kuan; Chen, Paul; Ruan, Roger

    2015-12-01

    In order to minimize coke yield during biomass catalytic fast pyrolysis (CFP) process, ethylene diamine tetraacetie acid (EDTA) chemical modification method is carried out to selectively remove the external framework aluminum of HZSM-5 catalyst. X-ray diffraction (XRD), nitrogen (N2)-adsorption and ammonia-temperature programmed desorption (NH3-TPD) techniques are employed to investigate the porosity and acidity characteristics of original and modified HZSM-5 samples. Py-GC/MS and thermo-gravimetric analyzer (TGA) experiments are further conducted to explore the catalytic effect of modified HZSM-5 samples on biomass CFP and to verify the positive effect on coke reduction. Results show that EDTA treatment does not damage the crystal structure of HZSM-5 zeolites, but leads to a slight increase of pore volume and pore size. Meanwhile, the elimination of the strong acid peak indicates the dealumination of outer surface of HZSM-5 zeolites. Treatment time of 2 h (labeled EDTA-2H) is optimal for acid removal and hydrocarbon formation. Among all modified catalysts, EDTA-2H performs the best for deacidification and can obviously increase the yields of positive chemical compositions in pyrolysis products. Besides, EDTA modification can improve the anti-coking properties of HZSM-5 zeolites, and EDTA-2H gives rise to the lowest coke yield.

  5. In vitro degradation of the 32kDa PS II reaction centre protein

    SciTech Connect

    Eckenswiller, L.C.; Greenberg, B.M. )

    1989-04-01

    The 32kDa thylakoid membrane protein is an integral component of the PS II reaction centre. The protein, although stable in the dark, undergoes light dependent turnover. Light from the UV, visible and far-red spectral regions induce 32kDa protein degradation. To better understand 32kDa protein metabolism, an in vitro degradation system is being developed. It consists of isolated thylakoid membranes than contain radiolabelled protein. The 32kDa protein is actively and specifically degraded when the thylakoid preparation is exposed to UV or visible radiation. The protein is stable in the dark. The herbicides (atrazine and DCMU) inhibit degradation in the in vitro system as they do in vivo. Additionally, several methods of isolating thylakoids are being compared to optimize the 32kDa protein degradation reaction. The preparations will be evaluated based on their ability to permit light dependent degradation of the 32kDa protein without affecting the other membrane components.

  6. The 32 kDa Enamelin Undergoes Conformational Transitions upon Calcium Binding

    PubMed Central

    Fan, Daming; Lakshminarayanan, Rajamani; Moradian-Oldak, Janet

    2008-01-01

    The 32 kDa hydrophilic and acidic enamelin, the most stable cleavage fragment of the enamel specific glycoprotein, is believed to play vital roles in controlling crystal nucleation or growth during enamel biomineralization. Circular dichroism and Fourier transform infrared spectra demonstrate that the secondary structure of the 32 kDa enamelin has a high content of α-helix (81.5%). Quantitative analysis on the circular dichroism data revealed that the 32 kDa enamelin undergoes conformational changes with a structural preference to β-sheet as a function of calcium ions. We suggest that the increase of β-sheet conformation upon presence of Ca2+ may allow preferable interaction of the 32 kDa enamelin with apatite crystal surfaces during enamel biomineralization. The calcium association constant of the 32 kDa enamelin calculated from the fitting curve of ellipticity at 222 nm is Ka = 1.55 (±0.13) × 103 M−1, indicating a relatively low affinity. Our current biophysical studies on the 32 kDa enamelin structure provide novel insights towards understanding the enamelin-mineral interaction and subsequently the functions of enamelin during enamel formation. PMID:18508280

  7. OpenDA: Open Source Generic Data Assimilation Environment and its Application in Geophysical Process Models

    NASA Astrophysics Data System (ADS)

    Weerts, A.; van Velzen, N.; Verlaan, M.; Sumihar, J.; Hummel, S.; El Serafy, G.; Dhondia, J.; Gerritsen, H.; Vermeer-Ooms, S.; Loots, E.; Markus, A.; Kockx, A.

    2011-12-01

    Data Assimilation techniques are essential elements in state-of-the-art development of models and their use in operational forecasting and real-time control in the fields of groundwater, surface water and soil systems. In meteorological and atmospheric sciences, steady improvements in numerical weather forecasting and climate prediction over the last couple of decades have been enabled to a large degree by the development of community-based models and data assimilation systems. The hydrologic community should learn from the experiences of the meteorological and atmospheric communities by accelerating the transition of hydrologic DA research into operations and developing community-supported, open-source modeling and forecasting systems and data assimilation tools. In 2010, a community based open source initiative named OpenDA was started. The openDA initiative bears similarities with the well-known openMI initiative. OpenDA makes use of a set of interfaces that describe the interaction between models, observations and data assimilation algorithms. It focuses on flexible applications in portable systems for modeling geophysical processes. It provides a generic interfacing protocol that allows combination of the implemented data assimilation techniques with, in principle, any time-stepping model describing a process (atmospheric processes, 3D circulation, 2D water flow, rainfall-runoff, unsaturated flow, groundwater flow, etc.). Presently, openDA features filtering techniques and calibration techniques. The presentation will give an overview of openDA and the results of some of its practical applications.

  8. [The behavior of superoxide dismutase (SOD) in serum of cows with abomasal displacement (DA)].

    PubMed

    Fürll, M; Dabbagh, M N; Fürll, B; Sattler, T

    2004-01-01

    After surgical reposition of displaced organs (abomasum, uterus, intestines) restoration of blood flow and oxygen supply generates oxygen radicals and other reactive oxygen species. SOD indicates radical stress of the organism. Subject of the study was the question if SOD can be detected in blood serum samples of cows and if there are differences in SOD activity between healthy cows and cows with Dislocatio abomasi (DA). We also wanted to investigate the influence of breed "Schwarzbunte" with DA (16 left/5 rights). The samples were drawn before and 1, 3 and 24 post op. Ten healthy cows of the same breed were also examined (2 weeks and 4-6 weeks after calving). There are no significant differences between the SOD activity of healthy cows and cows with DA, but the SOD activity of cows with left DA is significant lower than the activity of cows with right DA. Post op. SOD activity decreases; 24 h after surgery cows with left but not with right DA show an increase of SOD activity similar to values before surgery. There is a close positive correlation between SOD activity and protein concentration as well as negative correlation to concentration of free fatty acids after surgery. The behaviour of SOD activity shows that the surgical replacement of the displaced abomasum can generate a depression of the antioxidative capacity of the organism. PMID:14983749

  9. The sandfly fauna (Diptera: Psychodidae: Phlebotominae) of the Parque Estadual da Serra da Tiririca, Rio de Janeiro, Brazil

    PubMed Central

    Rodrigues, Andressa Alencastre Fuzari; Barbosa, Vanessa de Araújo; Andrade, José Dilermando; Brazil, Reginaldo Peçanha

    2013-01-01

    Cutaneous leishmaniasis (CL) in the state of Rio de Janeiro is sporadic and can be characterised as a peridomestic transmission that occurs in modified natural environments. The aim of this work was to study the fauna and ecological characteristics of sandflies in an environmentally protected area (the State Park of Serra da Tiririca) within the remnants of the Atlantic Forest in the municipalities of Niterói and Maricá and their possible relationship with leishmaniasis. Captures were performed using light traps during the night once a month for one year in both sylvatic environments and areas surrounding homes near the park. A total of 1,037 sandflies were captured, belonging to nine genera and 12 species: Evandromyia tupynambai (34.1%), Migonemyia migonei (20.6%), Brumptomyia cunhai (13.8%), Micropygomyia schreiberi (9.7%), Psathyromyia lanei (6.5%), Brumptomyia nitzulescui (5.7%), Evandromyia edwardsi (5.4%), Nyssomyia intermedia (2.8%), Evandromyia cortelezzii (0.6%), Pintomyia bianchigalatiae (0.5%), Lutzomyia longipalpis (0.2%) and Sciopemyia microps (0.1%). Both Mg. migonei and Ny. intermedia may be acting as vectors of CL in this area. PMID:24141956

  10. Negative regulation of human immunodeficiency virus type 1 expression in monocytes: role of the 65-kDa plus 50-kDa NF-kappa B dimer.

    PubMed

    Raziuddin; Mikovits, J A; Calvert, I; Ghosh, S; Kung, H F; Ruscetti, F W

    1991-11-01

    Although monocytic cells can provide a reservoir for viral production in vivo, their regulation of human immunodeficiency virus type 1 (HIV-1) transcription can be either latent, restricted, or productive. These differences in gene expression have not been molecularly defined. In THP-1 cells with restricted HIV expression, there is an absence of DNA-protein binding complex formation with the HIV-1 promoter-enhancer associated with markedly less viral RNA production. This absence of binding was localized to the NF-kappa B region of the HIV-1 enhancer; the 65-kDa plus 50-kDa NF-kappa B heterodimer was preferentially lost. Adding purified NF-kappa B protein to nuclear extracts from cells with restricted expression overcomes this lack of binding. In addition, treatment of these nuclear extracts with sodium deoxycholate restored their ability to form the heterodimer, suggesting the presence of an inhibitor of NF-kappa B activity. Furthermore, treatment of nuclear extracts from these cells that had restricted expression with lipopolysaccharide increased viral production and NF-kappa B activity. Antiserum specific for NF-kappa B binding proteins, but not c-rel-specific antiserum, disrupted heterodimer complex formation. Thus, both NF-kappa B-binding complexes are needed for optimal viral transcription. Binding of the 65-kDa plus 50-kDa heterodimer to the HIV-1 enhancer can be negatively regulated in monocytes, providing one mechanism restricting HIV-1 gene expression. PMID:1946356

  11. Myelin management by the 18.5–kDa and 21.5–kDa classic myelin basic protein isoforms

    PubMed Central

    Harauz, George; Boggs, Joan M.

    2013-01-01

    The classic myelin basic protein (MBP) splice isoforms range in nominal molecular mass from 14 to 21.5 kDa, and arise from the gene in the oligodendrocyte lineage (Golli) in maturing oligodendrocytes. The 18.5-kDa isoform that predominates in adult myelin adheres the cytosolic surfaces of oligodendrocyte membranes together, and forms a two-dimensional molecular sieve restricting protein diffusion into compact myelin. However, this protein has additional roles including cytoskeletal assembly and membrane extension, binding to SH3-domains, participation in Fyn-mediated signaling pathways, sequestration of phosphoinositides, and maintenance of calcium homeostasis. Of the diverse post-translational modifications of this isoform, phosphorylation is the most dynamic, and modulates 18.5-kDa MBP’s protein-membrane and protein-protein interactions, indicative of a rich repertoire of functions. In developing and mature myelin, phosphorylation can result in microdomain or even nuclear targeting of the protein, supporting the conclusion that 18.5-kDa MBP has significant roles beyond membrane adhesion. The full-length, early-developmental 21.5-kDa splice isoform is predominantly karyophilic due to a non-traditional P-Y nuclear localization signal, with effects such as promotion of oligodendrocyte proliferation. We discuss in vitro and recent in vivo evidence for multifunctionality of these classic basic proteins of myelin, and argue for a systematic evaluation of the temporal and spatial distributions of these protein isoforms, and their modified variants, during oligodendrocyte differentiation. PMID:23398367

  12. Characteristics of 26 kDa antigen of H. Pylori by Monoclonal Antibody.

    PubMed

    Ghahremani, Hossein; Farshad, Shohreh; Amini Najafabadi, Hossein; Kashanian, Susan; Momeni Moghaddam, Mohammad Amin; Moradi, Nariman; Paknejad, Maliheh

    2015-02-01

    Alkylhydroperoxide reductase (AhpC, the 26 kDa antigen) is one of the abundant antioxidant enzymes in Helicobacter pylori and seems to have a good potential for use in development of immunoassays to detect H. pylori infection in clinical specimens. This study aimed to investigate some properties of this antigen by the produced monoclonal antibodies. Five established hybridoma cell lines secreting monoclonal antibodies (MAbs) against 26 kDa antigen of H. pylori were cultivated and MAbs were purified by affinity chromatography. Subsequently, MAbs were conjugated with biotin, and different combinations of capture and tracer antibodies used in sandwich ELISA. Immunoblotting of bacterial extracts were performed to estimate aggregation status of the antigen. Release of antigen from the cultivated bacteria on solid media was examined by sandwich ELISA, and also, existence of interference in fecal extract was investigated by immunoblotting and sandwich ELISA. Our findings showed that the MAbs against 26 kDa antigen of H. pylori could recognize three bands of nearly 25 kDa, 50 kDa, and 75 kDa in immunoblotting. This study also indicated presence of more antigens in the culture medium around the bacteria than the bacterial extract itself. The results of sandwich ELISA and immunoblotting on fecal extracts suggest the presence of interfering agents that prevent detection of antigen by antibody in ELISA but not in immunoblotting. In this study the oligomerization of the 26 kDa antigen, presence of interfering agents in stool matrix, and release of antigen to outside of bacteria, were demonstrated. PMID:25530147

  13. Naloxone-induced jumping activity in morphine-dependent mice: a pharmacological study on the role of DA2 receptors.

    PubMed

    Cerbo, R; Boni, B; De Lena, C; Cesarino, F; Meco, G; Feliciani, M; Formisano, R; Casacchia, M

    1984-03-30

    The morphine withdrawal syndrome is strictly related to modifications on neurotransmittorial systems at central and peripheral levels. Dopamine seems to play an important role. Particularly in the experimental withdrawal syndrome the jumping activity seems to be related to a hypersensitivity of DA receptors. While the role of DA1 receptors has been extensively studied, using agonist and antagonist drugs, the role of DA2 receptors is still little known. In our study we evaluated the changes of the jumping response that was induced by substances active on DA2 receptors (lisuride, tiapride) in mice made acutely dependent on morphine, in which we induced a withdrawal syndrome with naloxone. Haloperidol (DA1-DA2 blocker) did not provoke significant changes. Either tiapride or lisuride determined a sharp increase of jumping. PMID:6712813

  14. 82-kDa choline acetyltransferase and SATB1 localize to β-amyloid induced matrix attachment regions.

    PubMed

    Winick-Ng, Warren; Caetano, Fabiana A; Winick-Ng, Jennifer; Morey, Trevor M; Heit, Bryan; Rylett, R Jane

    2016-01-01

    The M-transcript of human choline acetyltransferase (ChAT) produces an 82-kDa protein (82-kDa ChAT) that concentrates in nuclei of cholinergic neurons. We assessed the effects of acute exposure to oligomeric amyloid-β1-42 (Aβ1-42) on 82-kDa ChAT disposition in SH-SY5Y neural cells, finding that acute exposure to Aβ1-42 results in increased association of 82-kDa ChAT with chromatin and formation of 82-kDa ChAT aggregates in nuclei. When measured by chromatin immunoprecipitation with next-generation sequencing (ChIP-seq), we identified that Aβ1-42-exposure increases 82-kDa ChAT association with gene promoters and introns. The Aβ1-42-induced 82-kDa ChAT aggregates co-localize with special AT-rich binding protein 1 (SATB1), which anchors DNA to scaffolding/matrix attachment regions (S/MARs). SATB1 had a similar genomic association as 82-kDa ChAT, with both proteins associating with synapse and cell stress genes. After Aβ1-42 -exposure, both SATB1 and 82-kDa ChAT are enriched at the same S/MAR on the APP gene, with 82-kDa ChAT expression attenuating an increase in an isoform-specific APP mRNA transcript. Finally, 82-kDa ChAT and SATB1 have patterned genomic association at regions enriched with S/MAR binding motifs. These results demonstrate that 82-kDa ChAT and SATB1 play critical roles in the response of neural cells to acute Aβ-exposure. PMID:27052102

  15. An Introduction to the DA-T Gibbs Sampler for the Two-Parameter Logistic (2PL) Model and beyond

    ERIC Educational Resources Information Center

    Maris, Gunter; Bechger, Timo M.

    2005-01-01

    The DA-T Gibbs sampler is proposed by Maris and Maris (2002) as a Bayesian estimation method for a wide variety of "Item Response Theory (IRT) models". The present paper provides an expository account of the DA-T Gibbs sampler for the 2PL model. However, the scope is not limited to the 2PL model. It is demonstrated how the DA-T Gibbs sampler for…

  16. 11 CFR 111.11 - Written questions under order (2 U.S.C. 437d(a)(1)).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 11 Federal Elections 1 2011-01-01 2011-01-01 false Written questions under order (2 U.S.C. 437d(a... PROCEDURE (2 U.S.C. 437g, 437d(a)) Enforcement § 111.11 Written questions under order (2 U.S.C. 437d(a)(1... submit sworn written answers to written questions and may specify a date by which such answers must...

  17. 11 CFR 111.11 - Written questions under order (2 U.S.C. 437d(a)(1)).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Written questions under order (2 U.S.C. 437d(a... PROCEDURE (2 U.S.C. 437g, 437d(a)) Enforcement § 111.11 Written questions under order (2 U.S.C. 437d(a)(1... submit sworn written answers to written questions and may specify a date by which such answers must...

  18. 82-kDa choline acetyltransferase and SATB1 localize to β-amyloid induced matrix attachment regions

    PubMed Central

    Winick-Ng, Warren; Caetano, Fabiana A.; Winick-Ng, Jennifer; Morey, Trevor M.; Heit, Bryan; Rylett, R. Jane

    2016-01-01

    The M-transcript of human choline acetyltransferase (ChAT) produces an 82-kDa protein (82-kDa ChAT) that concentrates in nuclei of cholinergic neurons. We assessed the effects of acute exposure to oligomeric amyloid-β1–42 (Aβ1–42) on 82-kDa ChAT disposition in SH-SY5Y neural cells, finding that acute exposure to Aβ1–42 results in increased association of 82-kDa ChAT with chromatin and formation of 82-kDa ChAT aggregates in nuclei. When measured by chromatin immunoprecipitation with next-generation sequencing (ChIP-seq), we identified that Aβ1–42 -exposure increases 82-kDa ChAT association with gene promoters and introns. The Aβ1–42 -induced 82-kDa ChAT aggregates co-localize with special AT-rich binding protein 1 (SATB1), which anchors DNA to scaffolding/matrix attachment regions (S/MARs). SATB1 had a similar genomic association as 82-kDa ChAT, with both proteins associating with synapse and cell stress genes. After Aβ1–42 -exposure, both SATB1 and 82-kDa ChAT are enriched at the same S/MAR on the APP gene, with 82-kDa ChAT expression attenuating an increase in an isoform-specific APP mRNA transcript. Finally, 82-kDa ChAT and SATB1 have patterned genomic association at regions enriched with S/MAR binding motifs. These results demonstrate that 82-kDa ChAT and SATB1 play critical roles in the response of neural cells to acute Aβ -exposure. PMID:27052102

  19. Characterization of the 105-kDa molecular chaperone. Identification, biochemical properties, and localization.

    PubMed

    Matsumori, Mika; Itoh, Hideaki; Toyoshima, Itaru; Komatsuda, Atsushi; Sawada, Ken-Ichi; Fukuda, Jun; Tanaka, Toshinobu; Okubo, Atsuya; Kinouchi, Hiroyuki; Mizoi, Kazuo; Hama, Tokiko; Suzuki, Akira; Hamada, Fumio; Otaka, Michiro; Shoji, Yutaka; Takada, Goro

    2002-11-01

    We have characterized the biochemical properties of the testis and brain-specific 105-kDa protein which is cross-reacted with an anti-bovine HSP90 antibody. The protein was induced in germ cells by heat stress, resulting in a protein which is one of the heat shock proteins [Kumagai, J., Fukuda, J., Kodama, H., Murata, M., Kawamura, K., Itoh, H. & Tanaka, T. (2000) Eur. J. Biochem.267, 3073-3078]. In the present study, we characterized the biochemical properties of the protein. The 105-kDa protein inhibited the aggregation of citrate synthase as a molecular chaperone in vitro. ATP/MgCl2 has a slight influence of the suppression of the citrate synthase aggregation by the 105-kDa protein. The protein possessed chaperone activity. The protein was able to bind to ATP-Sepharose like the other molecular chaperone HSP70. A partial amino-acid sequence (24 amino-acid residues) of the protein was determined and coincided with those of the mouse testis- and brain-specific APG-1 and osmotic stress protein 94 (OSP94). The 105-kDa protein was detected only in the medulla of the rat kidney sections similar to OSP94 upon immunoblotting. The purified 105-kDa protein was cross-reacted with an antibody against APG-1. These results suggested that APG-1 and OSP94 are both identical to the 105-kDa protein. There were highly homologous regions between the 105-kDa protein/APG-1/OSP94 and HSP90. The region of HSP90 was also an immunoreactive site. An anti-bovine HSP90 antibody may cross-react with the 105-kDa protein similar to HSP90 in the rat testis and brain. We have investigated the localization and developmental induction of the protein in the rat brain. In the immunohistochemical analysis, the protein was mainly detected in the cytoplasm of the nerve and glial cells of the rat brain. Although the 105-kDa protein was localized in all rat brain segments, the expression pattern was fast in the cerebral cortex and hippocampus and slow in the cerebellum. PMID:12423363

  20. High resolution structure of cleaved Serpin 42 Da from Drosophila melanogaster

    PubMed Central

    2014-01-01

    Background The Drosophila melanogaster Serpin 42 Da gene (previously Serpin 4) encodes a serine protease inhibitor that is capable of remarkable functional diversity through the alternative splicing of four different reactive centre loop exons. Eight protein isoforms of Serpin 42 Da have been identified to date, targeting the protease inhibitor to both different proteases and cellular locations. Biochemical and genetic studies suggest that Serpin 42 Da inhibits target proteases through the classical serpin ‘suicide’ inhibition mechanism, however the crystal structure of a representative Serpin 42 Da isoform remains to be determined. Results We report two high-resolution crystal structures of Serpin 42 Da representing the A/B isoforms in the cleaved conformation, belonging to two different space-groups and diffracting to 1.7 Å and 1.8 Å. Structural analysis reveals the archetypal serpin fold, with the major elements of secondary structure displaying significant homology to the vertebrate serpin, neuroserpin. Key residues known to have central roles in the serpin inhibitory mechanism are conserved in both the hinge and shutter regions of Serpin 42 Da. Furthermore, these structures identify important conserved interactions that appear to be of crucial importance in allowing the Serpin 42 Da fold to act as a versatile template for multiple reactive centre loops that have different sequences and protease specificities. Conclusions In combination with previous biochemical and genetic studies, these structures confirm for the first time that the Serpin 42 Da isoforms are typical inhibitory serpin family members with the conserved serpin fold and inhibitory mechanism. Additionally, these data reveal the remarkable structural plasticity of serpins, whereby the basic fold is harnessed as a template for inhibition of a large spectrum of proteases by reactive centre loop exon ‘switching’. This is the first structure of a Drosophila serpin reported to date

  1. The rare DAT coding variant Val559 perturbs DA neuron function, changes behavior, and alters in vivo responses to psychostimulants

    PubMed Central

    Mergy, Marc A.; Gowrishankar, Raajaram; Gresch, Paul J.; Gantz, Stephanie C.; Williams, John; Davis, Gwynne L.; Wheeler, C. Austin; Stanwood, Gregg D.; Hahn, Maureen K.; Blakely, Randy D.

    2014-01-01

    Despite the critical role of the presynaptic dopamine (DA) transporter (DAT, SLC6A3) in DA clearance and psychostimulant responses, evidence that DAT dysfunction supports risk for mental illness is indirect. Recently, we identified a rare, nonsynonymous Slc6a3 variant that produces the DAT substitution Ala559Val in two male siblings who share a diagnosis of attention-deficit hyperactivity disorder (ADHD), with other studies identifying the variant in subjects with bipolar disorder (BPD) and autism spectrum disorder (ASD). Previously, using transfected cell studies, we observed that although DAT Val559 displays normal total and surface DAT protein levels, and normal DA recognition and uptake, the variant transporter exhibits anomalous DA efflux (ADE) and lacks capacity for amphetamine (AMPH)-stimulated DA release. To pursue the significance of these findings in vivo, we engineered DAT Val559 knock-in mice, and here we demonstrate in this model the presence of elevated extracellular DA levels, altered somatodendritic and presynaptic D2 DA receptor (D2R) function, a blunted ability of DA terminals to support depolarization and AMPH-evoked DA release, and disruptions in basal and psychostimulant-evoked locomotor behavior. Together, our studies demonstrate an in vivo functional impact of the DAT Val559 variant, providing support for the ability of DAT dysfunction to impact risk for mental illness. PMID:25331903

  2. The rare DAT coding variant Val559 perturbs DA neuron function, changes behavior, and alters in vivo responses to psychostimulants.

    PubMed

    Mergy, Marc A; Gowrishankar, Raajaram; Gresch, Paul J; Gantz, Stephanie C; Williams, John; Davis, Gwynne L; Wheeler, C Austin; Stanwood, Gregg D; Hahn, Maureen K; Blakely, Randy D

    2014-11-01

    Despite the critical role of the presynaptic dopamine (DA) transporter (DAT, SLC6A3) in DA clearance and psychostimulant responses, evidence that DAT dysfunction supports risk for mental illness is indirect. Recently, we identified a rare, nonsynonymous Slc6a3 variant that produces the DAT substitution Ala559Val in two male siblings who share a diagnosis of attention-deficit hyperactivity disorder (ADHD), with other studies identifying the variant in subjects with bipolar disorder (BPD) and autism spectrum disorder (ASD). Previously, using transfected cell studies, we observed that although DAT Val559 displays normal total and surface DAT protein levels, and normal DA recognition and uptake, the variant transporter exhibits anomalous DA efflux (ADE) and lacks capacity for amphetamine (AMPH)-stimulated DA release. To pursue the significance of these findings in vivo, we engineered DAT Val559 knock-in mice, and here we demonstrate in this model the presence of elevated extracellular DA levels, altered somatodendritic and presynaptic D2 DA receptor (D2R) function, a blunted ability of DA terminals to support depolarization and AMPH-evoked DA release, and disruptions in basal and psychostimulant-evoked locomotor behavior. Together, our studies demonstrate an in vivo functional impact of the DAT Val559 variant, providing support for the ability of DAT dysfunction to impact risk for mental illness. PMID:25331903

  3. A Influência da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos

    NASA Astrophysics Data System (ADS)

    da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

    2006-08-01

    O universo em que vivemos possui segredos jamais imaginados pelo homem, fruto da pequena proporção que ocupamos diante de um cosmos infinito. A astronomia funciona como um instrumento que sacia a sede humana em desvendar esses segredos, estudando as galáxias, quasares, pulsares além da existência de todos os elementos que preenchem o espaço cósmico, o vácuo, não mais vazio como se pensou em outros tempos. A mídia explora esse campo de forma mística e também científica. A difusão adequada e dentro dos padrões educacionais vigentes, de conceitos astronômicos, se faz necessária, devido sua presença nos conteúdos escolares, centros de ciência e na mídia, de modo geral. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros introduziu conceitos astronômicos desde a pré-escola até o Ensino Médio. Num estudo realizado com 1.032 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um questionário que abordava conheciment os básicos em astronomia, como estes foram adquiridos e qual era a infra-estrutura oferecida pela escola: para 66,2% dos entrevistados o professor já fez alguma apresentação a respeito de astronomia. O presente estudo revelou também que 44,5% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 28,1% através da televisão e 27,4% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio na forma em que os alunos obtiveram seus conhecimentos astronômicos, a mídia ainda explora e muitas vezes desperta o interesse pela astronomia com assuntos que não fazem parte de nosso cotidiano como, por exemplo, o homem na Lua, os projetos espaciais e a primeira viagem de um astronauta brasileiro no espaço. Porém, em certos casos, a mídia pode promover conhecimentos incompletos ou mesmo equivocados sobre os conceitos que envolvam

  4. Essential 170-kDa subunit for degradation of crystalline cellulose by Clostridium cellulovorans cellulase

    SciTech Connect

    Shoseyov, O.; Doi, R.H. )

    1990-03-01

    The cellulase complex from Clostridium cellulovorans has been purified and its subunit composition determined. The complex exhibits cellulase activity against crystalline cellulose as well as carboxymethylcellulase (CMCase) and cellobiohydrolase activities. Three major subunits are present with molecular masses of 170, 100, and 70 kDa. The 100-kDa subunit is the major CMCase, although at least four other, minor subunits show CMCase activity. The 170-kDa subunit has the highest affinity for cellulose, does not have detectable enzymatic activity, but is necessary for cellulase activity. Immunological studies indicate that the 170-kDa subunit is not required for binding of the catalytic subunits to cellulose and therefore does not function solely as an anchor protein. Thus this core subunit must have multiple functions. The authors propose a working hypothesis that the binding of the 170-kDa subunit converts the crystalline cellulose to a form that is capable of being hydrolyzed in a cooperative fashion by the associated catalytic subunits.

  5. Influence of 120 kDa Pyruvate:Ferredoxin Oxidoreductase on Pathogenicity of Trichomonas vaginalis

    PubMed Central

    Song, Hyun-Ouk

    2016-01-01

    Trichomonas vaginalis is a flagellate protozoan parasite and commonly infected the lower genital tract in women and men. Iron is a known nutrient for growth of various pathogens, and also reported to be involved in establishment of trichomoniasis. However, the exact mechanism was not clarified. In this study, the author investigated whether the 120 kDa protein of T. vaginalis may be involved in pathogenicity of trichomonads. Antibodies against 120 kDa protein of T. vaginalis, which was identified as pyruvate:ferredoxin oxidoreductase (PFOR) by peptide analysis of MALDI-TOF-MS, were prepared in rabbits. Pretreatment of T. vaginalis with anti-120 kDa Ab decreased the proliferation and adherence to vaginal epithelial cells (MS74) of T. vaginalis. Subcutaneous tissue abscess in anti-120 kDa Ab-treated T. vaginalis-injected mice was smaller in size than that of untreated T. vaginalis-infected mice. Collectively, the 120 kDa protein expressed by iron may be involved in proliferation, adhesion to host cells, and abscess formation, thereby may influence on the pathogenicity of T. vaginalis. PMID:26951982

  6. Experience with ATLAS MySQL PanDA database service

    NASA Astrophysics Data System (ADS)

    Smirnov, Y.; Wlodek, T.; De, K.; Hover, J.; Ozturk, N.; Smith, J.; Wenaus, T.; Yu, D.

    2010-04-01

    The PanDA distributed production and analysis system has been in production use for ATLAS data processing and analysis since late 2005 in the US, and globally throughout ATLAS since early 2008. Its core architecture is based on a set of stateless web services served by Apache and backed by a suite of MySQL databases that are the repository for all PanDA information: active and archival job queues, dataset and file catalogs, site configuration information, monitoring information, system control parameters, and so on. This database system is one of the most critical components of PanDA, and has successfully delivered the functional and scaling performance required by PanDA, currently operating at a scale of half a million jobs per week, with much growth still to come. In this paper we describe the design and implementation of the PanDA database system, its architecture of MySQL servers deployed at BNL and CERN, backup strategy and monitoring tools. The system has been developed, thoroughly tested, and brought to production to provide highly reliable, scalable, flexible and available database services for ATLAS Monte Carlo production, reconstruction and physics analysis.

  7. Synergistic effects of melatonin and deprenyl against MPTP-induced mitochondrial damage and DA depletion.

    PubMed

    Khaldy, Hoda; Escames, Germaine; León, Josefa; Bikjdaouene, Leila; Acuña-Castroviejo, Darío

    2003-01-01

    Previous studies showed a synergistic effect of melatonin and deprenyl against dopamine (DA) autoxidation in vitro. Since oxidative stress is implicated in Parkinson's disease (PD), we explored the effects of melatonin plus deprenyl administration in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD in C57/Bl6 mice. Melatonin, but not deprenyl prevents the inhibition of mitochondrial complex I and the oxidative damage in nigrostriatal neurons induced by MPTP. With the dose used deprenyl recovers 50% DA levels and tyrosine hydroxylase activity depressed by the neurotoxin, normalizing locomotor activity of mice. Melatonin, which was unable to counteract MPTP-induced DA depletion and inhibition of tyrosine hydroxylase activity, potentiates the effect of deprenyl on catecholamine turnover and mice ambulatory activity. These results suggest a dissociation of complex I inhibition from DA depletion in this model of Parkinson's disease. The data also support that a combination of melatonin, which improves mitochondrial electron transport chain and reduces oxidative damage, and deprenyl, which promotes the specific function of the rescued neurons, i.e. DA turnover, may be a promising strategy for the treatment of PD. PMID:12600724

  8. In vitro study on the interaction between the 32 kDa enamelin and amelogenin

    PubMed Central

    Fan, Daming; Du, Chang; Sun, Zhi; Lakshminarayanan, Rajamani; Moradian-Oldak, Janet

    2015-01-01

    Enamel extracelluar matrix components play vital roles in controlling crystal nucleation and growth during enamel formation. We investigated the interaction between the 32 kDa enamelin fragment and amelogenin using immunochemical and biophysical methods. Immunoprecipitation studies revealed that the 32 kDa enamelin and amelogenin eluted together from a Protein A column. Dynamic light scattering results showed that the 32 kDa enamelin had a profound effect on amelogenin assembly at pH 8.0, causing partial dissociation of the nanospheres, in a dose-dependent manner. The appearance of an isodichroic point and the shifting and intensity decrease of the ellipticity minima in the circular dichroism spectra of amelogenin following the addition of the 32 kDa enamelin were indicative of conformational changes in amelogenin and of a direct interaction between the two macromolecules. Our results collectively demonstrate that the 32 kDa enamelin has a direct interaction with amelogenin in vitro. Our current studies provide novel insights into understanding possible cooperation between enamelin and amelogenin in macromolecular self-assembly and in controlling enamel mineral formation. PMID:19263522

  9. Morphogenetic Studies of the Drosophila DA1 Ventral Olfactory Projection Neuron.

    PubMed

    Shen, Hung-Chang; Wei, Jia-Yi; Chu, Sao-Yu; Chung, Pei-Chi; Hsu, Tsai-Chi; Yu, Hung-Hsiang

    2016-01-01

    In the Drosophila olfactory system, odorant information is sensed by olfactory sensory neurons and relayed from the primary olfactory center, the antennal lobe (AL), to higher olfactory centers via olfactory projection neurons (PNs). A major portion of the AL is constituted with dendrites of four groups of PNs, anterodorsal PNs (adPNs), lateral PNs (lPNs), lateroventral PNs (lvPNs) and ventral PNs (vPNs). Previous studies have been focused on the development and function of adPNs and lPNs, while the investigation on those of lvPNs and vPNs received less attention. Here, we study the molecular and cellular mechanisms underlying the morphogenesis of a putative male-pheromone responding vPN, the DA1 vPN. Using an intersection strategy to remove background neurons labeled within a DA1 vPN-containing GAL4 line, we depicted morphological changes of the DA1 vPN that occurs at the pupal stage. We then conducted a pilot screen using RNA interference knock-down approach to identify cell surface molecules, including Down syndrome cell adhesion molecule 1 and Semaphorin-1a, that might play essential roles for the DA1 vPN morphogenesis. Taken together, by revealing molecular and cellular basis of the DA1 vPN morphogenesis, we should provide insights into future comprehension of how vPNs are assembled into the olfactory neural circuitry. PMID:27163287

  10. Morphogenetic Studies of the Drosophila DA1 Ventral Olfactory Projection Neuron

    PubMed Central

    Yu, Hung-Hsiang

    2016-01-01

    In the Drosophila olfactory system, odorant information is sensed by olfactory sensory neurons and relayed from the primary olfactory center, the antennal lobe (AL), to higher olfactory centers via olfactory projection neurons (PNs). A major portion of the AL is constituted with dendrites of four groups of PNs, anterodorsal PNs (adPNs), lateral PNs (lPNs), lateroventral PNs (lvPNs) and ventral PNs (vPNs). Previous studies have been focused on the development and function of adPNs and lPNs, while the investigation on those of lvPNs and vPNs received less attention. Here, we study the molecular and cellular mechanisms underlying the morphogenesis of a putative male-pheromone responding vPN, the DA1 vPN. Using an intersection strategy to remove background neurons labeled within a DA1 vPN-containing GAL4 line, we depicted morphological changes of the DA1 vPN that occurs at the pupal stage. We then conducted a pilot screen using RNA interference knock-down approach to identify cell surface molecules, including Down syndrome cell adhesion molecule 1 and Semaphorin-1a, that might play essential roles for the DA1 vPN morphogenesis. Taken together, by revealing molecular and cellular basis of the DA1 vPN morphogenesis, we should provide insights into future comprehension of how vPNs are assembled into the olfactory neural circuitry. PMID:27163287